PETITIONERS:
     Julian M. Whitaker, MD; Durk Pearson and Sandy Shaw; American
     Preventive Medical Association; and Pure Encapsulations, Inc.

ADDRESS:
     c/o Emord & Associates, P.C.
     1050 Seventeenth Street, NW, Suite 600
     Washington, DC 20036
     

SUBJECT:
     Petition for Health Claim: Folic Acid, Vitamin B6,
     and Vitamin B12 and Vascular Disease

Food and Drug Administration

Office of Food Labeling (HFS-150)

200 C Street, SW

Washington, DC 20204

1. Introduction and Statement of Purpose

The undersigned, Julian M. Whitaker, M.D., Durk Pearson and Sandy Shaw; the American Preventive Medical Association, and Pure Encapsulations, Inc. (Petitioners), pursuant to Section 403 (r)(5)(D) of the Federal Food, Drug & Cosmetic Act (FDCA) (21 USC § 343(r)(5)(D)), submit this petition for a health claim concerning the relationship between the consumption of folic acid, vitamin B6, and vitamin B12 (hereinafter "the 3B-vitamins") and vascular disease risk. Attached hereto, and constituting a part of this petition, are all of the items specified in 21 CFR § 101.70 (f). The text of the proposed model claim is set forth in section III of this petition.

Petitioners believe this petition represents a logical and valid evaluation of the scientific studies and clinical trials concerning the relationship between the 3B-vitamins and vascular disease risk. Those studies demonstrate that: (1) blood homocysteine levels are directly related to cardiovascular disease risk, (2) increased consumption of the 3B-vitamins lowers blood homocysteine levels, and (3) increased consumption of the 3B-vitamins lowers vascular disease risk. The scientific evidence justifies permitting a health claim that links consumption of the 3B-vitamins with a reduction in vascular disease risk (See, McCully Report, Attachment 2). Such a health claim directly responds to a major public health concern in the United States: cardiovascular disease accounts for more deaths per year than any other disease or group of diseases. 21 CFR § 101.75(b) (1999).

Moreover, the 3B-vitamins offer a safe, inexpensive, readily accessible means for reducing vascular disease risks population wide. See, Hornberger, 1998. Conventional vascular disease risk factors include age, gender, heredity, inactivity, smoking, high cholesterol, hypertension, and diabetes. See, Folsom, 1998. While some risk factors can be reduced with simple changes in diet and lifestyle, other risk factors, such as age, gender, and heredity, are currently incapable of reduction. Additional factors, such as high cholesterol, hypertension, and diabetes, can require costly and hazardous therapies to reduce risk. By contrast, supplementing the diet with the 3B-vitamins is less costly and burdensome. It offers a meaningful reduction of vascular disease risk without a reduction in quality of life. See, Hornberger, 1998. The proposed health claim asserts a feasible means of reducing vascular disease risk and serves U.S. Department of Health and Human Services (DHHS) policy by addressing a significant health problem in the U.S. population. See, 61 Fed. Reg. 296, 297 (Jan. 4, 1996).

A diet supplemented with the 3B-vitamins offers health benefits with the potential to reduce the occurrence of vascular disease. See, McCully Report, pp. 3-4, Attachment 2. Recent studies indicate that a significant number of lives are saved from vascular disease as a result of increased consumption of the 3B-vitamins. See, e.g., Boushey (1995); Pietrzik, 1997. Considering efficacy, cost effectiveness, and the potential lives saved, greater use of the 3B-vitamins resulting from awareness of the proposed health claim will serve the national interest and DHHS policy.

Additional studies demonstrate that many persons currently suffer health effects that could be alleviated by increasing 3B-vitamin intake. See, e.g., Boushey (1995); Pietrzik, 1997. While many foods contribute the 3B-vitamins to the diet either naturally or by fortification, scientific studies demonstrate that common processing and cooking methods significantly reduce the bioavailability of the 3B-vitamins. See, McNulty, 1994. Only a source of free folic acid, vitamin B6, and vitamin B12 (such as dietary supplements), not exposed to processing or cooking, can ensure that efficacious quantities of the 3B-vitamins are ingested daily. (See, McCully Report, p.2, Attachment 2). The limited bioavailability of the 3B-vitamins in the average diet, and the fact that less than one third of American adults consume the recommended number of servings of foods containing the 3B vitamins, makes 3B vitamin supplementation an essential alternative to achieve population wide vascular disease risk reduction. See, USDA and DHHS, Third Report on Nutrition Monitoring in the United States--Executive Summary, 1995; McCully Report, p.2, Attachment 2). Furthermore, USDA researchers found that based on a cross sectional study of more than 30,00 individuals, 80 per cent of the U.S. population consumes less than the RDI of vitamin B6. ***The scientific studies described in this petition directly address this important public health issue and further national and DHHS policy by reducing vascular disease risk.

The underlying scientific data demonstrate that daily consumption of the 3B-vitamins will reduce vascular disease risk. More than fifty-nine human studies between 1976 and 1999, when taken as a whole, justify approval of the petitioned claim. The 3B-vitamins have always been natural components of the American diet, and specifically included in fortified foods for years. See, McCully Report, Attachment 2. The scientific data provide substantial evidence of the vascular benefits resulting from daily consumption of the 3B-vitamins.

Petitioners believe that the truthful and succinct health information conveyed by their proposed health claim will enable consumers to make prudent and effective choices about their health care and lifestyles. Labeling dietary supplements with the proposed 3B-vitamins health claim would augment previously published statements by DHHS concerning the prevention and treatment of vascular disease. The petitioned claim will accurately impart the scientific understanding about the relationship between the 3B-vitamins and the risks of vascular disease, enabling consumers to make informed choices in the marketplace.

Consistent with the decision in Pearson v. Shalala, 164 F.3d 650, (D.C. Cir. 1999), reh’g denied en banc, No. 98-5043, 1999 U.S. App. LEXIS 5954 (Apr. 2, 1999), Petitioners respectfully request that in its action on this petition the agency define "significant scientific agreement" in 21 CFR § 101.14 by explaining precisely what principles the agency has employed to determine what degree, quality, and nature of evidence it expects to satisfy its "significant scientific agreement" standard. In addition, and consistent with Pearson, if the agency finds the proposed claim not to satisfy "significant scientific agreement," the Petitioners request that the agency authorize it nevertheless, with such disclaimer or disclaimers as it reasonably deems necessary to avoid a potentially misleading connotation.

This petition seeks FDA approval of the proposed claim for use on dietary supplements of folic acid, vitamin B6, and vitamin B12 manufactured in accordance with U.S. Pharmacopeia (USP) specifications. The 3B-vitamins meet the definition of a "substance" provided by 21 CFR § 101.14(a). Substance is defined as a food or a component of food regardless of whether the food is in conventional or dietary supplement form. The 3B-vitamins are a component of foods found naturally in conventional foods such as green leafy vegetables, orange juice, and beans.

The proposed health claim conforms to the relevant requirements of 21 CFR § 101.14(b). Section 101.14(b) provides:

Conformance with each requirement of 21 CFR § 101.14(b) is discussed below.

In satisfaction of section 101.14(b)(1), the proposed health claim associates the 3B-vitamins with vascular disease. Vascular disease includes diseases of the heart and circulatory system. Coronary heart disease is the most common and serious form of vascular disease primarily affecting the heart muscle and supporting blood vessels. 21 CFR § 101.75(a) (1999). Coronary heart disease is a major public health concern in the United States, primarily because it accounts for more deaths than any other disease or group of diseases. 21 CFR § 101.75(b) (1999). Stroke, a closely related vascular disease, is the third leading cause of death in the U.S. See, CDC, www.cdc.gov/nchs/fastat, 1998. The petitioner meets the requirements of 21 CFR § 101.14(b)(1) by associating the 3B-vitamins with a disease for which the general U.S. population is at risk. FDA has determined that the adult population is at risk for coronary heart disease and cardiovascular disease.

Section 101.14(b)(2) regards health claims for substances to be consumed at decreased dietary levels. The proposed health claim does not promote consumption at decreased dietary levels. Therefore, section 101.14(b)(2) does not apply to the proposed health claim.

In conformity with section 101.14(b)(3)(i), the 3B-vitamins contribute nutritive value and retain their nutritive attribute when consumed at or above the current Reference Daily Intake (RDI) values. Those RDI values are 400 μg/day for folic acid, 2 mg/day for vitamin B6, and 6 μg/day for vitamin B12. The nutritive contribution of the 3B-vitamins is widely recognized. The substance is asubstances are naturally occurring nutritive component in a wide variety of foods such as green leafy vegetables, orange juice, and beans. The nutritive value is recognized by FDA through its nutritional labeling regulation, 21 CFR § 101.9. Section 101.9(c)(8)(iv) states that folic acid (folate), vitamin B6, and vitamin B12 are essential in human nutrition. The RDI values provided in § 101.9(c)(8)(iv) establish the minimum intake of the 3B-vitamins necessary for maintaining adequate nutrition. The proposed health claim promotes intake quantities equal to or greater than the RDI values. Since the proposed health claim meets or exceeds the RDI levels for the 3B-vitamins, the nutritive value of the substance is retained at the levels necessary to justify the proposed health claim. Therefore, the proposed health claim meets the requirements of 21 CFR § 101.14(b)(3)(i).

In conformity with section 101.14(b)(3)(ii), the 3B-vitamins are both foods and food ingredients and are safe and lawful at the levels necessary to justify the proposed health claim. As mentioned above, the 3B-vitamins are natural ingredients of common foods such as green leafy vegetables, orange juice, and beans. They are also added as food ingredients to processed foods such as fortified cereals per 21 CFR § 104.20. The 3B-vitamins are also available as foods or food ingredients when commonly sold as dietary supplements. The FDCA deems dietary supplements a food under 21 U.S.C. §321(ff). Accordingly, the 3B-vitamins are both foods and food ingredients according to 21 CFR § 101.14(b)(3)(ii).

The 3B-vitamins are generally recognized as safe and lawful at the levels necessary to justify the proposed health claim. Vitamin B6 is generally recognized as safe with no pre-determined daily intake limitation under 21 CFR § 184.1676. Vitamin B12 is generally recognized as safe with no pre-determined daily intake limitation under 21 CFR § 184.1945. Folic acid (folacin) is listed as a food additive under 21 CFR § 172.345. Food additive status is sufficient to demonstrate safety according to 21 CFR § 101.7(f).

The maximum (safe) daily intake of vitamins B6 and B12 is generally limited to the amount reasonably required to accomplish an intended nutritive effect. 21 CFR § 172.5 (1999). Accordingly, vitamins B6 and B12 are generally recognized as safe at any daily intake level justified for a particular nutritive effect, i.e., the inverse relationship effect presented in the proposed health claim. Similarly, the safe upper limit for folic acid has not been established but has generally been set at 400the CDC recommends periconceptual consumption at 800 μg/day. 58 FR 53254 at 53257 (October 14, 1993). However, the addition of folic acid to special dietary foods is only limited to the amount necessary to meet the special dietary needs for which the food is formulated. 21 CFR § 172.345(g) (1999). Consequently, foods formulated for the realization of the proposed health claim are only limited to the maximum daily intake level necessary to justify the proposed health claim, i.e., to achieve results similar to those presented in scientific studies. The safe upper folic acid daily limit for the proposed health claim, therefore, is only limited by the nutritive purpose of the dietary supplementation. Accordingly, the 3B-vitamins are generally recognized as safe and lawful at the daily intake levels necessary to justify the proposed health claim. Therefore, the proposed health claims complies with the safety and lawfulness requirements of 21 CFR § 101.14(b)(3)(ii).

The National Institutes of Health (NIH), after a deliberative review of the scientific evidence, has established the upper safe intake limit of the 3B-vitamins. See, National Institutes of Health, Institute of Medicine, Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, National Academy Press, 1999, http://odp.od.nih.gov.ods. NIH has identified the Tolerable Upper Intake Level (UL) for adults at 1,000 μg/day for folic acid (exclusive of food folate) and 100 mg/day for vitamin B6. Id. For children, the folic acid UL was established at 300-800 μg/day and the vitamin B6 UL was established at 30-80 mg/day. Id. NIH could not derive a UL for vitamin B12 but found no risks associated with intakes as high as 3,700 μg/day for the general population, i.e., adults and children. Id.; see also, Butterworth, 1989; Chasen-Taber, 1996. The proposed health claim promotes dietary intakes that are well below the safety limits established by NIH.

Furthermore, safety concerns with overconsumption of 3B-vitamins are mitigated when comparing the proposed claim to the current RDI values and the NIH ULs. The proposed claim matches the RDI value for folate and vitamin B12 and, therefore, does not raise safety concerns beyond those already existing with the RDI value. For vitamin B6, however, the proposed claim promotes an intake of 3 mg/day that exceeds the RDI value of 2 mg/day. That higher value remains safe when considering that it is well below the most conservative UL value of 30 mg/day (for children).

The safety of the proposed health claim can also be shown when examining the dietary habits of the general U.S. population. NIH has determined that 95% of the general U.S. population has an intake of less than 900 μg/day for folate (and less than 1,700 μg/day for pregnant women), less than 6 to 10 mg/day for vitamin B6, and less than 27 μg/day for vitamin B12. Id. If the 95th percentile of the population were to supplement their diet with the maximum recommendation of the proposed health claim, daily intake for those persons would be 1,300 μg/day for folate (2,100 μg/day for pregnant women), 13 mg/day for vitamin B6, and 32 μg/day for vitamin B12. Each of those maximum intakes are well below the ULs established by NIH. Since the proposed claim promotes an intake level well within the upper safety limit, even when considering the possibility of increased consumption, any safety concerns of overconsumption are mitigated.

In summary, since the 3B-vitamins meet the requirements set forth in 21 CFR § 101.14(b), the preliminary requirements of 21 CFR § 101.70 are fully satisfied.

There exists significant agreement among experts who study the field of vascular disease concerning the association between 3B-vitamins, homocysteine, and vascular disease risk factors. See, McCully Report, Attachment 2. Summaries of those meta-analyses and literature surveys discussing the inverse relationship between the 3B-vitamins and vascular disease risk are presented below:

• Boushey et al. (1995): Meta-analysis of prospective, cross-sectional, and case-control studies of coronary artery disease, cerebrovascular disease, and peripheral arterial vascular disease to determine whether folic acid reduced the risk of coronary artery disease. No studies directly studying the relationship between folic acid and vascular disease were found, but the association was inferred from the demonstrated folic acid-homocysteine relationship. "Higher folic acid intake by reducing homocysteine levels promises to prevent arteriosclerotic vascular disease." 13,500 to 50,000 coronary artery disease deaths annually could be avoided with increased folic acid intake.
• Durand et al. (1998): Survey article reviewing studies evaluating folate deficiency and disease risk. Folate deficiency is a major cause of hyperhomocysteinemia which is fully recognized as an independent risk factor for atherothrombosis. Epidemiological and recent experimental studies have demonstrated that folate deficiency might increase the risk of cardiovascular disease by increasing circulating homocysteine levels.
• Herzlich (1996): Editorial reviewing articles studying the relationship between homocysteine and occlusive atherosclerosis suggest that folic acid consumption among the general population may be too low.
• Hornberger (1998): Article estimating the cost-benefit analysis of a study to determine the disease-preventative effects of folate. The analysis found that the screening costs and annual cost and inconvenience of taking folate is small compared with the consequences of stroke, ischemic heart disease, or death.
• Omenn et al. (1998): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12. Found that current evidence links folic acid and cardiovascular disease risk. No conclusion is provided for an association between vitamins B6 and B12 and disease risk.
• Swain et al. (1997): Survey article reviewing the association between folate and vascular disease risk concludes that there is some biologic plausibility, but not currently direct proof, for the assumption that folate supplementation may prevent heart disease, stroke, and peripheral arterial disease.

Summaries of those meta-analyses and literature surveys discussing the direct relationship between homocysteine and vascular disease risk are summarized below:

• Boushey et al. (1995): Meta-analysis of prospective, cross-sectional, and case-control studies of coronary artery disease, cerebrovascular disease, and peripheral arterial vascular disease to determine whether homocysteine was a risk factor for arteriosclerotic vascular disease. Homocysteine was found to be an independent risk factor for vascular disease equivalent to the risk from cholesterol.
• Drown (1995): Survey article reviewing studies by Selhub, Pancharuniti, Stampfer, Stamler, Tsai, and Kang on the relation between homocysteine and disease risk. Substantial data and the weight of evidence suggest that elevated homocysteine level is a clinically important risk factor for coronary artery disease.
• Futterman et al. (1997): Survey article reviewing the association between homocysteine and vascular disease. Homocystinuria said to have a number of adverse effects, including early development of severe coronary, peripheral, and cerebral atherosclerosis and thromboembolic venous disease. If untreated, most patients with homocystinuria die of vascular disease before age 30.
• Kang et al. (1992): Survey article reviewing the association between homocysteine and vascular disease stated that many retrospective studies have substantiated the positive correlation between moderate hyperhomocysteinemia and occlusive arterial diseases. The article also found it reasonable to assume that the accumulations of excessive homocysteine causes damage to endothelial and smooth muscle cells and alters the activity of coagulation factors.
• Klor et al. (1997): Survey article reviewing the association between homocysteine and vascular disease states that (1) to date, 38 studies were conducted investigating the connection between elevated homocysteine levels and atherosclerotic risk, and 34 of those 38 studies were able to confirm a connection, (2) that homocysteine must be seen as an independent risk factor for the development of atherosclerotic changes, and (3) that an increase in homocysteine concentration can cause atherosclerosis even in absence of classical risk factors such as smoking, gender, age, hypertension, and lipid metabolism disorders.
• Malinow (1990): Editorial reviewing articles studying the relationship between homocysteine and occlusive atherosclerosis concludes that multiple studies have demonstrated that an elevated homocysteine level is associated with coronary, cerebrovascular, and peripheral arterial diseases, and that the association is frequent and independent of most other risk factors for atherosclerosis.
• McNulty (1995): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12 states that elevated homocysteine concentration is now considered to be an independent risk factor for coronary heart disease. The prevalence of hyperhomocysteinemia is between 28% and 42% in different populations with coronary heart disease, and the risk of premature occlusive vascular disease is reported to be about 30 times greater for people with hyperhomocysteinemia relative to normal controls.
• Pietrzik et al. (1997): Survey article reviewing the association between atherosclerosis and folic acid, vitamin B6, and vitamin B12 found a striking agreement between numerous studies; 34 of 38 studies found an association between elevated homocysteine levels and the risk for atherosclerotic disease.
• Refsum et al. (1998): Survey article reviewing the association between homocysteine and cardiovascular disease states that epidemiologic studies have unequivocally established that an elevated plasma homocysteine level both predicts and precedes the occurrence of cardiovascular disease. The relation between the homocysteine level and cardiovascular disease is graded without an apparent threshold and remains strong after adjustment for potential confounders.
• Ueland et al. (1989): Survey articles reviewing the association between homocysteine and vascular disease concluded that a moderate increase in homocysteine level is statistically associated with premature arteriosclerosis in coronary, cerebral, and peripheral arteries. Intermediate homocysteinemia seems to be an arteriosclerotic risk factor independent of conventional risk factors like plasma cholesterol, hypertension, smoking, and diabetes.

Summaries of those meta-analyses and literature surveys discussing the inverse relationship between the 3B-vitamins and homocysteine are summarized below:

• Bailey (1995): Textbook reviewing O’Keefe study where a 70 day study of 17 women with various folate intakes demonstrated that homocysteine levels were higher for the cohort with the lowest folate intake.
• Boushey et al. (1995): Meta-analysis of prospective, cross-sectional, and case-control studies of coronary artery disease, cerebrovascular disease, and peripheral arterial vascular disease to estimate the reduction of homocysteine by folic acid. Higher levels of folic acid were shown to reduce homocysteine levels.
• Futterman et al. (1997): Survey article reviewing the association between folate, vitamin B6, and vitamin B12 and homocysteine states that elevated blood concentrations of homocysteine may be reduced successfully with folate, vitamin B6, and vitamin B12.
• Kang et al. (1992): Survey article reviewing the association between homocysteine and vascular disease stated that, irrespective of etiology, moderate and intermediate hyperhomocysteinemia is readily correctable by supplementation with folate and/or betaine.
• Klor et al. (1997): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12 finds that a negative correlation between homocysteine levels and supply of the folate, vitamin B6, and vitamin B12 has been shown by numerous studies.
• McNulty (1995): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12 states that there is a strong inverse relationship between homocysteine and folate, and, to a lesser extent, vitamin B6 and vitamin B12. While treatment with vitamins B6 or B12 has not always produced an effect on plasma homocysteine levels, studies on humans have consistently shown a homocysteine-lowering effect of folic acid at high doses (typically 5 mg/day) in both healthy and hyperhomocysteinemic subjects, even in the absence of overt folate deficiency.
• Omenn et al. (1998): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12 finds that current evidence links folic acid and homocysteine. No opinion is provided for vitamin B6 because no definitive evidence was available demonstrating an inverse association with homocysteine levels. No conclusion is provided for vitamin B12.
• Pietrzik et al. (1997): Survey article reviewing the association between atherosclerosis and folic acid, vitamin B6, and vitamin B12 found an inverse relationship between folic acid, vitamin B6, and vitamin B12 and homocysteine blood concentration. Supplementation with those vitamins resulted in a significant reduction in homocysteine levels.
• Pietrzik et al. (1998): Survey article reviewing the association between homocysteine and folic acid, vitamin B6, and vitamin B12 found an inverse relationship between folic acid and homocysteine. The vitamins B6 and B12 were not associated with homocysteine. Conclusions on vitamins B6 and B12 were not based on a critical survey of articles or meta-analyses, or even data from other studies; the author bases his conclusions on his own study, which was not described in the article.
• Swain et al. (1997): Survey article reviewing the association between folate and vascular disease risk finds that homocysteine levels are reduced by folic acid administration.
• Ueland et al. (1989): Survey articles reviewing the association between homocysteine and vascular disease concluded that plasma homocysteine level is decreased by high doses of folic acid.

Thirty years ago Dr. Kilmer McCully led the research into the discovery of homocysteine as an independent risk factor for coronary heart disease. Later studies have built on Dr. McCully’s work by confirming and characterizing the nature of the homocysteine risk factor. Further investigation has also revealed a relationship between the 3B-vitamins and blood homocysteine levels. The 3B-vitamins have been found to influence homocysteine levels and thereby reduce the homocysteine risk factor for vascular disease. Those studies providing detailed human clinical data are summarized in Tables 1, 2, and 3.

There is significant scientific agreement among qualified experts that there is an inverse relationship between the consumption of the 3B-vitamins and vascular disease risk. At least nineteen published scientific articles reporting results of human clinical trials have examined the 3B-vitamin-vascular disease risk relationship. Fifteen articles conclude that there is a relationship while only four articles (Dalrey, 1995; Giles, 1998; Pancharuniti, 1994; and Siri, 1998) found no relationship. All of those studies are briefly described below.

• Aronow et al. (1997): In a case-control study, 281 controls were compared to 219 cases with coronary artery disease. Low folate and vitamin B12 levels were associated with higher prevalence of coronary artery disease.
• Chasen-Taber et al. (1996): A case-control study prospectively comparing folate, vitamin B6, and homocysteine levels and the risk of myocardial infarction and coronary disease fatality in 333 men matched to an equal number of equivalent controls. Low folate and vitamin B6 levels were found to contribute to the risk of myocardial infarction; however, these data were not statistically significant.
• Dalrey et al. (1995): A case-control study evaluated the folic acid, vitamin B6, and vitamin B12 levels of 584 healthy subjects and 150 subjects with premature coronary artery disease. Although there were no significant differences between the two groups for folic acid, vitamin B6, and vitamin B12, substantially lower pyridoxal phosphate levels (a metabolite of vitamin B6) were observed. The conclusions, however, were limited to the main trait of the study population: all were of French Canadian descent.
• Ellis et al. (1995): A study compared the incidence of acute cardiac chest pain or myocardial infarction of patients treated with vitamin B6 therapy with the incidence rates for the local population. Patients receiving vitamin B6 were found to have a lesser incidence rate than those receiving conventional therapy.
• Folsom et al. (1998): A case-control study evaluated coronary heart disease risk factors in 527 control subjects compared to a mixed population of 232 test subjects. Vitamin B6 was found to reduce risk and possibly provide independent protection from coronary heart disease.
• Ford et al. (1998): An analysis examined the relationship between serum folate and risk for cardiovascular-related mortality or disease. The underlying data were obtained from 2657 subjects of the National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. A weak association between low folate levels and cardiovascular disease mortality was found; however, the analysis did not examine particular disease-specific endpoints.
• Giles et al. (1998): An analysis examined the relationship between serum folate and coronary heart disease. The underlying data were obtained from 1,921 subjects of the National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. An inverse relationship was evidenced for serum folate and coronary heart disease risk for adults under age 55. However, in adults over the age of 55, higher folate levels were associated with increased disease risk. Findings could be secondary to unmeasured factors confounding the association between folate and heart disease.
• Giles et al. (1995): An analysis evaluated whether serum folate concentrations of ≤ 9.2 nmol/L were associated with ischemic stroke. The underlying data were obtained from 2,006 subjects of the National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Low folate concentrations were found to increase risk for ischemic stroke, especially in blacks.
• Lewis (1992): A case-control study compared homocysteine and folate levels in 108 control subjects and 101 patients with coronary artery disease. Patients with coronary artery disease were found to have lower folate levels than controls.
• Morrison et al. (1996): A 15 year retrospective cohort study of 5,056 men evaluated folate levels and the risk of fatal coronary heart disease. A statistically significant association between folate levels and the risk of fatal coronary heart disease was found.
• Morrison (1998): A letter to the editor discussed a 1993 follow-up on a subgroup from the Morrison 1996 study. Folate consumption was inversely related to fatal coronary heart disease risk.
• Pancharuniti et al. (1994): A case-control study compared homocysteine, vitamin B12, and folate levels in 108 male controls and 101 males with coronary artery disease. Low folate was associated with increased risk for coronary artery disease. No significant univariate association between vitamin B12 and coronary artery disease was observed. Several rationales were provided to explain how, after adjustment for homocysteine and standard coronary artery disease risk factors, vitamin B12 concentrations were found to be directly associated with risk for coronary artery disease.
• Peterson et al. (1998): A retrospective study of 38 patients evaluated the effect of therapy with folic acid, vitamin B6, and vitamin B12 on atherosclerosis. Patients with homocysteine levels greater than 14 μmol/L were treated with 2.5 mg/d of folic acid, 25 mg/d of vitamin B6, and 250 μg/d of vitamin B12. Prior to treatment, ultrasound measurements confirmed that plaque area increased at a rate of 0.31 cm²/year. After treatment, plaque area decreased by 0.05 cm²/year.***what area
• Rath et al. (1996): Fifty-five patients with coronary artery disease were monitored for effects of nutritional supplement therapy including folic acid, vitamin B6, and vitamin B12. Prior to therapy the progression of coronary artery calcification averaged 44% per year. After one year of therapy, progression of coronary calcification decreased 15%.
• Rimm et al. (1998): A prospective study examining the relationship between folic acid and vitamin B6 to the incidence of nonfatal myocardial infarction and fatal coronary heart disease. The study followed dietary intake of 80,082 women for 14 years. A substantially lesser risk of disease was found with subjects that had the greatest intake of folic acid or vitamin B6. Further reduction of disease risk was found with subjects who had the greatest intake of both folic acid and vitamin B6. Patients using mulitvitamins, the most prevalent source of folic acid and vitamin B6, demonstrate a reduced disease risk as well.
• Robinson (1998): A case-control study compared disease risk with homocysteine, folate, vitamin B6, and vitamin B12 levels in 800 controls and 750 patients with vascular disease. Low folate and vitamin B6 levels were associated with increased atherosclerotic disease risk independent of other disease risk factors. Vitamin B12 was not associated with vascular disease.
• Selhub et al. (1995): A study of 1041 elderly subjects evaluated the relation between carotid-artery stenosis and homocysteine, folic acid, vitamin B6, and vitamin B12 levels. Low folate and vitamin B6 levels were associated with increased risk of extracranial carotid-artery stenosis in the elderly. Vitamin B12 levels were weakly associated with stenosis.
• Siri (1998): A case-control study compared 88 controls with 131 subjects to evaluate the relationship between homocysteine, folic acid, vitamin B6, and vitamin B12 with the risk of coronary atherosclerosis. Subjects with the lowest vitamin B12 levels had greatest risk of atherosclerosis, partly independently of homocysteine. Folic acid and vitamin B6 were not associated with coronary atherosclerosis disease risk, possibly because of the effect of patient dietary changes or unknown mechanisms on the study.
• Verhoef (1997): A case-control study compared the folic acid, vitamin B6, vitamin B12, and homocysteine levels of 189 controls and 131 subjects with coronary atherosclerosis. Unexpectedly, folic acid, vitamin B6, and vitamin B12 levels were found to be greater with the cases. Possible explanations rested on the limited sample size and other potential determinants like genetics.

There is significant scientific agreement among qualified experts that there is a direct relationship between homocysteine and vascular disease risk. At least thirty-five published scientific articles reporting results of human clinical trials have examined the homocysteine-vascular disease risk relationship. Thirty-two articles conclude that there is a relationship with only three articles (Alfthan, 1994; Evans, 1997; and Folson, 1998) finding no relationship. All of those studies are briefly described below.

• Alfthan et al. (1997): Blood samples from 20 randomly chosen men from several countries were evaluated for homocysteine levels. Homocysteine was found to be significantly associated with cardiovascular disease.
• Alfthan et al. (1994): In a 9-year case-control study, 265 controls were compared to 265 cases with either myocardial infarction or stroke. No significant association was seen between homocysteine and atherosclerotic disease, myocardial infarction, or stroke. The lack of association may have been due to an exceptionally low predisposition to homocysteinemia in the Finnish study population.
• Arnesen et al. (1995): In a 4-year case-control study, 478 controls were compared to 122 cases with coronary heart disease. Homocysteine was found to be an independent risk factor for coronary heart disease. There was no threshold level abovebelow which homocysteine was not associated with coronary heart disease.
• Aronow et al. (1997): In a case-control study, 281 controls were compared to 219 cases with coronary artery disease. High homocysteine levels were associated with higher prevalence of coronary artery disease.
• Boers et al. (1985): In a prospective study, the homocysteine levels were evaluated in 75 subjects with arterial disease, cerebrovascular disease, or myocardial infarction. Persons with homocystinuria were found susceptible to the development of premature occlusive arterial disease, intermittent claudication, renovascular hypertension, and ischemic cerebrovascular disease.
• Chasen-Taber et al. (1996): A case-control study prospectively compared folate, vitamin B6, and homocysteine levels and the risk of myocardial infarction and coronary disease fatality in 333 men matched to an equal number of equivalent controls. Men with the top 5% of homocysteine levels had an almost three-fold increase risk in myocardial infarction.
• Clarke et al. (1991): A case-control study compared homocysteine levels in 27 control subjects and 123 patients with vascular disease. Hyperhomocysteinemia was found to be an independent risk factor for vascular disease, including coronary heart disease.
• Coull et al. (1990): A case-control study compared homocysteine levels in 31 control subjects and 99 patients with acute stroke, transient ischemic attacks, and other risk factors of cerebrovascular disease. The data suggested that elevated homocysteine may be an independent risk factor for cerebrovascular disease.
• den Heijer et al. (1996): A case-control study compared homocysteine levels in 269 controls and 269 patients with deep-vein thrombosis. High homocysteine levels were found to be a risk factor for deep-vein thrombosis.
• Dierkes et al. (1998): A case-control study compared classic risk factors and homocysteine levels in 231 control subjects and 191 patients with coronary artery disease. Hyperhomocysteinemia was found to be at least as important as conventional coronary artery disease risk factors.
• Evans et al. (1997): A nested case-control study evaluated risk factors in 712 men. No association of homocysteine concentration and heart disease was detected. Results were possibly influenced by the extended storage of blood samples of up to 11 years.
• Folsom et al. (1998): A case-control study evaluated coronary heart disease risk factors in 527 control subjects compared to a mixed population of 232 test subjects. Results suggest that homocysteine is not independently associated with coronary heart disease. Data is contrasted with other studies and a prior study of the same population where a non-significant positive association was found between homocysteine and carotid intima-media thickness. The study population was previously found to have a positive association between homocysteine and carotid intima-media thickness (see Malinow (1993)).
• Genest et al. (1990): A case-control study compared homocysteine levels in 255 control subjects and 170 men with premature coronary artery disease. Elevated homocysteine was found to be an independent risk factor for the development of premature coronary atherosclerosis in men.
• Graham et al. (1997): A case-control study compared homocysteine levels in 800 control subjects and 750 patients with atherosclerotic vascular disease. Increased homocysteine level was found to be an independent risk factor for vascular disease similar to the risk associated with smoking and hypertension.
• Hopkins et al. (1995): A case-control study compared homocysteine levels in 155 control subjects and 162 patients with early coronary artery disease. The data suggested that a high homocysteine level is an independent risk factor for early familial coronary artery disease.
• Kang et al. (1986): A case-control study compared homocysteine levels in 202 control subjects and 241 patients with coronary artery disease. Subjects with coronary artery disease had statistically significantly greater homocysteine levels than controls.
• Malinow et al. (1990): A case-control study compared homocysteine and folic acid levels in 259 controls and 99 subjects with coronary heart disease. Male and female patients with coronary heart disease had higher levels of homocysteine than did control subjects.
• Malinow et al. (1993): A case-control study evaluated homocysteine and carotid intimal-medial wall thickness in 287 controls and 287 subjects. Higher homocysteine levels were observed with subjects having thicker carotid intimal-medial wall thickness.
• Molgaard et al. (1992): A case-control study compared homocysteine levels in 98 controls and 78 subjects with intermittent claudication. Homocysteine was found to be a risk factor for intermittent claudication independent of other risk factors for peripheral atherosclerotic disease, such as smoking, hypertension, diabetes mellitus, hypercholesterolaemia, hypertriglyceridaemia, low levels of high-density-lipoprotein (HDL) cholesterol, and age.
• Murphy-Chutorian et al. (1985): A case-control study evaluated homocysteine levels of 39 controls and 99 men with coronary artery disease. Subjects with coronary artery disease evidenced elevated homocysteine levels.
• Nygard et al. (1997): A prospective study of 587 patients with coronary artery disease evaluated homocysteine levels and disease risk factors. A strong association was found between homocysteine levels and overall mortality, myocardial infarction history, and death due to cardiovascular disease. A weak association was observed between homocysteine and coronary artery disease.
• Nygard et al. (1995): A prospective study of 16,176 men and women were evaluated for homocysteine level and established cardiovascular risk factors. Elevated plasma homocysteine level was associated with major components of the cardiovascular risk profile, i.e., male sex, old age, smoking, high blood pressure, elevated cholesterol level, and lack of exercise.
• Pancharuniti et al. (1994): A case-control study compared homocysteine, vitamin B12, and folate levels in 108 male controls and 101 males with coronary artery disease. Homocysteine was found to be an independent risk factor for coronary artery disease.
• Olszewski et al. (1991): A case-control study compared homocysteine levels in 7 normolipemic men and 9 hypercholesterolemic men. The homocysteine levels in lipoprotein fractions were found to be higher in hypercholesterolemic men.
• Ridker et al. (1999): A case-control study compared disease risk with homocysteine in 244 controls and 122 patients with myocardial infarction, stroke, percutaneous transluminal coronary angioplasty, or coronary artery bypass graft. Elevated homocysteine levels were associated with increased cardiovascular disease risk.
• Robinson (1998): A case-control study compared disease risk with homocysteine, folate, and vitamin B6 levels in 800 controls and 750 patients with vascular disease. Elevated homocysteine levels were associated with increased disease risk independent of traditional disease risk factors.
• Selhub et al. (1995): A study of 1041 elderly subjects evaluated the relation between carotid-artery stenosis and homocysteine, folic acid, vitamin B6, and vitamin B12 levels. Elevated homocysteine levels were associated with increased risk of extracranial carotid-artery stenosis in the elderly.
• Stampfer et al. (1992): 14,916 male physicians, in which 271 subsequently developed myocardial infarction, were analyzed for homocysteine levels together with matched controls in a nested case-control study. Moderately high homocysteine levels were associated with risk of myocardial infarction independent of other factors.
• Ubbink et al. (1991): A case-control study compared homocysteine levels of 195 controls with 163 patients with typical angina. Homocysteine levels were significantly elevated in patients with occluded coronary arteries.
• Verhoef (1997): A case-control study compared the folic acid, vitamin B6, vitamin B12, and homocysteine levels of 189 controls and 131 subjects with coronary atherosclerosis. The study revealed a significant linear trend of increasing fasting homocysteine with increasing number of occluded arteries, correcting for sex, age, and other potential confounders. Data showed a positive correlation between plasma homocysteine and risk of severe coronary atherosclerosis over a wide range of homocysteine levels, without a clear cutoff point below which there is no increased level of risk.
• von Eckardstein et al. (1994): A case-control study evaluated homocysteine as a cardiovascular risk factor in 156 controls and 199 male coronary heart disease patients. Homocysteine level was found to be an independent coronary risk factor.
• Voutilainen et al. (1998): A study compared homocysteine levels and common carotid artery intima-media wall thickness in 513 patients before and during participation in the Antioxidant Supplementation in Atherosclerosis Prevention study. Elevated plasma homocysteine levels were associated with early atherosclerosis, as manifested by increased common carotid artery intima-media wall thickness, in middle-aged eastern Finnish men.
• Wald et al. (1998): In a prospective study of 21,520 men homocysteine levels were obtained from 229 men suffering fatal ischemic heart disease and 1,126 matched controls. Risk of ischemic heart disease was greater in men with greater homocysteine levels, with a demonstrated continuous dose-response relationship.
• Wilcken et al. (1976): A case-control study compared homocysteine levels of 22 controls and 25 subjects with coronary artery disease. Patients with premature coronary artery disease were shown to have a reduced ability to metabolize homocysteine.
• Wu et al. (1994): A case-control study evaluated homocysteine as a coronary artery disease risk factor in 168 controls and 266 patients with early coronary artery disease. Early coronary artery disease was associated with high concentrations of homocysteine.

There is significant scientific agreement among qualified experts that there is an inverse relationship between the 3B-vitamins and homocysteine. At least eighteen published scientific articles reporting results of human clinical trials have examined the 3B-vitamin-homocysteine relationship. All eighteen articles conclude that there is a relationship, with only one article (Lassier-Cacan, 1996) finding no relationship for only vitamin B6. All of those studies are briefly described below.

• Dierkes et al. (1998): A case-control study compared classic risk factors and homocysteine levels in 231 control subjects and 191 patients with coronary artery disease. Homocysteine level was found to be weakly related to folate and vitamin B12.
• Dudman et al. (1993): A case-control study compared homocysteine levels in 31 control subjects and 131 patients with premature circulatory disease who were treated with folic acid and other nutrients. Results indicate that mild homocysteinemia in premature vascular disease may be caused by a folate deficiency.
• Hopkins et al. (1995): A case-control study compared homocysteine levels in 155 control subjects and 162 patients with early coronary artery disease. Subjects with early familial coronary artery disease and low folate levels had exaggerated elevations of homocysteine.
• Hultberg et al. (1997): A case-control study compared homocysteine levels in 20 control subjects and 49 stroke patients. Patients with decreased folate levels exhibited increased homocysteine levels.
• Jacob et al. (1994): A switch-back type study evaluated homocysteine levels of 10 men denied folate intake. For most subjects, decreased folate intake resulted in increased homocysteine levels.
• Jacob et al. (1998): A study evaluated homocysteine levels of 8 women with limited folate intake. Marginal folate deficiency resulted in significantly elevated homocysteine levels.
• Jacques et al. (1999): An evaluation of the homocysteine levels in the fifth and sixth follow-up of 756 controls and 350 subjects from the Framingham Offspring Study. Subjects receiving folate fortification in their diets exhibited lower homocysteine levels.
• Jacques et al. (1996): Homocysteine levels of 365 subjects with a methylenetetrahydrofolate reductase genetic defect were evaluated. Individuals with thermolabile methylenetetrahydrofolate reductase were found to have a greater folate requirement to regulate homocysteine levels.
• Lewis (1992): A case-control study compared homocysteine and folate levels in 108 control subjects and 101 patients with coronary artery disease. Folate levels were found to have an inverse relationship to homocysteine.
• Lussier-Cacan et al. (1996): A study of 380 men and 204 women compared homocysteine and vitamin levels. Subjects with the lowest vitamin B12 and folate values had significantly higher homocysteine concentrations. No correlation was noticed for vitamin B6.
• Malinow et al. (1997): A case-control study compared homocysteine and folic acid levels in 102 controls and 140 subjects with acute myocardial infarction or angina pectoris. Folic acid supplementation was found to lower homocysteine levels.
• O’Keefe et al. (1995): A 70-day study evaluated 17 women with various folate intakes. Homocysteine levels were higher for the cohort with the lowest folate intake.
• Olszewski et al. (1989) and Olszewski (1991 correction of calculation error): A prospective controlled study evaluated 12 male survivors of acute myocardial infarction and 10 control subjects for changes in homocysteine levels after 21 days of therapy with pyridoxine, folate, cobalamin, choline, riboflavin, and troxerutin. After 21 days, homocysteine levels in test subjects receiving therapy decreased 68% while control subjects increased slightly.
• Pancharuniti et al. (1994): A case-control study compared homocysteine, vitamin B12, and folate levels in 108 male controls and 101 males with coronary artery disease. Folate and vitamin B12 concentrations were inversely associated with homocysteine concentrations.
• Selhub et al. (1993): A study of 1160 subjects evaluated the relation between homocysteine, folic acid, vitamin B6, and vitamin B12 levels. Homocysteine levels exhibited a strong inverse association with folate levels, with weaker inverse association between homocysteine levels and vitamin B6 and B12 levels.
• Siri (1998): A case-control study compared 88 controls with 131 subjects to evaluate the relationship between homocysteine, folic acid, vitamin B6, and vitamin B12 with the risk of coronary atherosclerosis. Subjects with the greatest folate and vitamin B12 levels showed statistically significantly lower homocysteine concentrations. Subjects with the greatest vitamin B6 levels showed significantly lower homocysteine concentrations.
• Tucker et al. (1996): A study of 885 elderly subjects examined the relationship between folate and homocysteine levels. Folate intake was found to reduce homocysteine levels. A clear dose-response relationship between folate and homocysteine was observed.
• Ubbink et al. (1993): A case-control study compared homocysteine, folic acid, vitamin B6, and vitamin B12 levels of 274 controls with 44 men with moderate hyperhomocysteinemia. Hyperhomocysteinemic men had significantly lower levels of folic acid, vitamin B6, and vitamin B12 as compared to controls. In a placebo-controlled follow-up study, therapy with a dietary supplement, homocysteine levels were normalized in hyperhomocysteinemic men within 6 weeks.

In summary, an overwhelming majority of the aforementioned scientific articles support the proposed health claim. The conclusions of the authors of those articles demonstrate that there is significant scientific agreement among qualified experts. Those experts repeatedly conclude that there is (1) an inverse relationship between 3B-vitamins and vascular disease risk, (2) a direct relationship between homocysteine and vascular disease risk, and (3) an inverse relationship between the 3B-vitamins and homocysteine. Accordingly, FDA should respect the well-considered conclusions of scientific experts on the vascular benefits of folic acid, vitamin B6, and vitamin B12 and approve the proposed claim.

Petitioners propose the following Model Claim for folic acid, vitamin B6, and vitamin B12 and vascular disease risk:

Attached are copies of the scientific studies and other information referenced in, and constituting the basis for, this Petition. To the best of the Petitioners' knowledge, all non-clinical studies relied upon were conducted in compliance with the good laboratory practices regulations set forth at 21 CFR Part 58, and all clinical or other human investigations relied upon were either conducted in accordance with the requirements for institutional review set forth at 21 CFR Part 56 or were not subject to such requirements in accordance with 21 CFR §§ 56.104 or 56.105, and were conducted in conformance with the requirements for informed consent set forth in 21 CFR § 50 et seq. See generally, 21 CFR § 101.70 (c)-(d).

The requested health claim approval contained in this petition is categorically excluded under 21 C.F.R. § 25.24.

For the foregoing reasons, the Petitioners request that the FDA approve the proposed health claim. The Petitioners look forward to working with the FDA in promulgating a regulation authorizing the use of a dietary supplement health claim concerning the association between folic acid, vitamin B6, and vitamin B12 and reduction in the risk of vascular disease.

Any questions concerning this Petition may be directed to Jonathan W. Emord, Esq., Emord & Associates, P.C., 1050 Seventeenth Street, NW, Suite 600, Washington DC 20036, (202) 466-6937.

The undersigned certify on behalf of the Petitioners that to the best of their knowledge and belief, the Petition includes all information and views on which the Petitioners rely and is a representative and balanced submission that includes unfavorable information as well as favorable information, known by the Petitioners to be pertinent to evaluation of the proposed health claim.

Jonathan W. Emord

Eleanor A. Kolton

Steven W. Allis

1050 Seventeenth Street, N.W.

Suite 600

Washington, D.C. 20036

P: (202) 466-6937

F: (202) 466-6938

e-mail: Emordal1@erols.com

Date: May 25, 1999

1. Alfthan G, et al., "Plasma homocysteine and cardiovascular disease mortality," Lancet, 349:397 (1997).
2. Alfthan G, et al., "Relation of serum homocysteine and lipoprotein(a) concentrations to atherosclerotic disease in a prospective Finnish population based study," Atherosclerosis, 106:9-19 (1994).
3. Arnesen E, et al., "Serum total homocysteine and coronary heart disease," Int'l J Epidemiol, 24:704-9, 1995.
4. Arnold B, "Folate intake and status of elderly patients in hospital," Med J Aust, 2:378, 1968.
5. Aronow WS and Ahn C, "Association between plasma homocysteine and coronary artery disease in older persons," Am J Cardiol, 80:1216-8, 1997.
6. Bailey LB, "Folate requirements and dietary recommendations," Folate in Health and Disease, 123-51, 1995.
7. Bates CJ, et al., "The discrepancy between normal folate and the folate RDA," Human Nutr: Appl Nutr, 36A:422-29, 1982.
8. Boers GHJ, et al., "Heterozygosity for homocystinuria in premature peripheral vascular and cerebral occlusive arterial disease," N Eng J Med, 313:709-15, 1985.
9. Boushey CJ, et al., "A quantitative assessment of plasma homocysteine as a risk factor for vascular disease: probable benefits of increasing folic acid intakes," JAMA, 274:1049-57, 1995.
10. Braun RD, "Serum folate and risk of fatal coronary heart disease," JAMA, 276:1222, 1996.
11. Butterworth CE, et al., "Folic acid safety and toxicity: a brief review," Am J Clin Nutr, 50:353-58, 1989.
12. "B-vitamins may cut heart disease risk," Harv Health Lett, 23:8, 1998.
13. Chasen-Taber L, et al., A prospective study of folate and vitamin B6 and risk of myocardial infarction in US physicians," J Am Coll Nutr, 15:135-43, 1996.
14. Clarke R, et al., "Hyperhomocysteinemia: An independent risk factor for vascular disease," N Eng J Med, 324:1149-55, 1991.
15. Cohen M and Bendich A, "Safety of pyrodoxine—a review of human and animal studies," Toxicol Lett, 34:129-39, 1986.
16. Colman N, et al., "Bioavailability of folate," Am J Clin Nutr, 29:235-6, 1976.
17. Coull BM, et al., "Elevated plasma homocyst(e)ine concentration as a possible independent risk factor for stroke," Stroke, 21:572-76, 1990.
18. Dalrey K, et al., "Homocysteine and coronary artery disease in French Canadian subjects: relation with vitamins B12, B6, pyridoxal phosphate, and folate," Am J Cardiol, 75:1107-11, 1995.
19. den Heijer M, et al., "Hyperhomocysteinemia as a risk factor for deep-vein thrombosis," N Engl J Med, 334:759-62, 1996.
20. Dierkes J, et al., "The diagnostic value of serum homocysteine concentration as a risk factor for coronary artery disease," Clin Chem Lab Med, 36:453-7, 1998.
21. Drown DJ, et al., "Homocysteine: an independent risk factor associated with coronary disease and other arterial occlusive diseases in adults," Prog Cardiovasc Nurs, 10(4):37-8, 1995.
22. Dudman NPB, et al., "Disordered methionine/homocysteine metabolism in premature vascular disease," Arterioscler Thromb, 13:1253-60, 1993.
23. Durand P, et al., " Folate deficiencies and cardiovascular pathologies," Clin Chem Lab Med, 36:419-429, 1998. Review
24. Ellis JM, et al., "Prevention of myocardial infarction by vitamin B6," Res Commun Mol Pathol Pharmacol, 89(2):208-20, 1995.
25. Evans RW, et al., "Homocyst(e)ine and risk of cardiovascular disease in multiple risk factor intervention trial," Arterioscler Thromb Vasc Biol, 17:1947-53, 1997.
26. Farhadi D, "Plasma homocysteine levels and mortality in patients with coronary artery disease," N Engl J Med, 337(22):1632, 1997.
27. Folsom AR, et al., "Prospective study of coronary heart disease incidence in relation to fasting total homocysteine, related genetic polymorphisms, and B vitamins: the Atherosclerosis Risk in Communities (ARIC) study," Circulation, 98:204-10, 1998.
28. Ford ES, et al., "Serum folate and chronic disease risk: findings from a cohort of United States adults," Int'l J Epidemiol, 27:592-8, 1998.
29. Futterman LG, et al., " Homocysteine and coronary artery disease," Am J Crit Care, 6:72-7, 1997.
30. Genest JJ, et al., "Plasma homocyst(e)ine levels in men with premature coronary artery disease," J Am Coll Cardiol, 16:1114-9, 1990.
31. Giles WH, et al., "Serum folate and chronic disease risk: findings from a cohort of United States adults," Ann Epidemiol, 8:490-6, 1998.
32. Giles WH, et al., "Serum folate and risk for ischemic stroke: First National Health and Nutrition Examination Survey epidemiologic follow-up study," Stroke, 26:1166-70, 1995.
33. Graham IM, et al., "Plasma homocysteine as a risk factor for vascular disease," JAMA, 277:1775-1781, 1997.
34. Graham IM, et al., Homocysteine metabolism: from basic science to clinical medicine, Kluwer Academic Publishers, 1997.
35. Herzlich BC, "Plasma Homocyst(e)ine, folate, vitamin B6 and coronary artery disease risk," J Am Coll Nutr, 15:109-10, 1996.
36. Hopkins PN, et al., "Higher plasma homocyst(e)ine and increased susceptibility to adverse effects of low folate in early familial coronary artery disease," Aeterioscler Thromb Vasc Biol, 15:1314-1320, 1995.
37. Hornberger J, "A cost benefit analysis of a cardiovascular disease prevention trial, using folate supplementation as an example," Am J Pub Health, 88:61-67, 1998.
38. Hultberg B, et al., "Marginal folate deficiency as a possible cause of hyperhomocysteinaemia in stroke patients," Eur J Clin Chem Biochem, 35:25-28, 1997.
39. Jacob RA, et al., "Homocysteine increases as folate decreases in plasma of healthy men during short-term dietary folate and methyl group restriction," J Nutr, 124:1072-80, 1994.
40. Jacob RA, et al., "Moderate folate depletion increases plasma homocysteine and decreases lymphocyte DNA methylation in postmenopausal women," J Nutr 128:1204-12, 1998.
41. Jacques PF, et al., "The effect of folic acid fortification on plasma folate and total homocysteine concentrations," N Engl J Med, 340:1449-54, 1999.
42. Jacques PF, et al., "Relation between folate status, a common mutation in methylenetetrahdrofolate reducatse, and plasma homocysteine concentrations," Circulation, 93:7-9, 1996.
43. Kang SS, et al., "Hyperhomocyst(e)inemia as a risk factor for occlusive vascular disease," Ann Rev Nutr, 12:279-98, 1992.
44. Kang SS, et al., "Protein-bound homocyst(e)ine: a possible risk factor for coronary artery disease," J Clin Invest, 77:1482-86, 1986.
45. Klör HU, et al., "Nutrition and cardiovascular disease," Eur J Med Res, 2:243-57, 1997.
46. Levin A, "Folate and heart disease: theoretical link needs study," Ann Intern Med, 126: I59-60, 1997.
47. Lewis CA, et al., "Plasma folate adequacy as determined by homocysteine level," Ann NY Acad Sci, 669:360-2, 1992.
48. Lussier-Cacan S, et al., "Plasma total homocysteine in healthy subjects: sex specific relation with biological traits," A, J Clin Nutr, 64:587-93, 1996.
49. Malinow MR, et al., "The effects of folic acid supplementation on plasma total homocysteine are modulated by multivitamin use and methylenetetrahydrofolate reductase genotypes," Arterioscler Thromb Vasc Biol, 17:1157-62, 1997.
50. Malinow MR, et al., "Homocyst(e)inemia in daily practice: levels in coronary artery disease," Corona Art Dis, 1:215-20, 1990.
51. Malinow MR, "Hyperhomocyst(e)inemia: A common and easily reversible risk factor for occlusive atherosclerosis," Circulation, 81:2004-6, 1990.
52. Malinow MR, "Carotid artery intimal-medial wall thickening and plasma homocyst(e)ine in asymptomatic adults," Circulation, 87:1107-18, 1993.
53. McCully KS, et al., The Heart Revolution, Harper Collins Publishers, 1999.
54. McCully KS, The Homocysteine Revolution, Keats Publishing, Inc., p.160, 1997.
55. McCully KS, "Atherosclerosis, serum cholesterol and the homocysteine theory: a study of 194 consecutive autopsies," Am J Med Sci, 299(4):217-21, 1990.
56. McCully KS, "Chemical pathology of homocysteine. I. Atherogenesis," Ann Clin Lab Sci 23(6):477-93, 1993.
57. McCully KS, "Chemical pathology of homocysteine. III. Cellular function and aging," Ann Clin Lab Sci, 24(2):134-52, 1994.
58. McCully KS, "Homocysteine and vascular disease," Nat Med, 2(4):386-9, 1996.
59. McCully KS, "Homocysteine metabolism in scurvy, growth and arteriosclerosis," Nature, 231(5302):391-2, 1971.
60. McCully KS, "Homocysteine, folate, vitamin B6, and cardiovascular disease," JAMA, 279(5):392-3, 1998.
61. McCully KS, "Homocysteinemia and arteriosclerosis," Am Heart J, 83(4):571-3, 1972.
62. McCully KS, "Homocysteinemia and arteriosclerosis: failure to isolate homocysteine thiolactone from plasma and lipoproteins," Res Commun Chem Pathol Pharmacol, 63(2):301-4, 1989.
63. McCully KS, "Homocystine, atherosclerosis and thrombosis: implications for oral contraceptive users," Am J Clin Nutr, 28(5):542-9, 1975.
64. McCully KS, "Homocystinuria, arteriosclerosis, methylmalonic aciduria, and methyltransferase deficiency: a key case revisited," Nutr Rev, 50(1):7-12, 1992.
65. McCully KS, "Importance of homocysteine-induced abnormalities of proteoglycan structure in arteriosclerosis," Am J Pathol, 59(1):181-94, 1970.
66. McCully KS, "Macromolecular basis for homocystein-induced changes in proteoglycan structure in growth and arteriosclerosis," Am J Pathol, 66(1):83-96, 1972.
67. McCully KS, "Vascular pathology of homocysteinemia: implications for the pathogenesis of arteriosclerosis," Am J Pathol, 56(1):111-28, 1969.
68. McCully KS, et al., "Chemopreventive and antineoplastic activity of N-homocysteine thiolactonyl retinamide," Carcinogenesis, 8(10):1559-62, 1987.
69. McCully KS, et al., "Homocysteine and lipid metabolism in atherogenesis: effect of the homocysteine thiolactonyl derivatives, thioretinaco and thioretinamide," Atherosclerosis, 83(2-3):197-206, 1990.
70. McCully KS, et al., "Homocysteine theory of arteriosclerosis," Atherosclerosis, 22(2):215-27, 1975.
71. McCully KS, et al., "Homocysteine thiolactone, N-homocysteine thiolactonyl retinamide, and platelet aggregation," Res Commun Chem Pathol Pharmacol, 56(3):349-60, 1987.
72. McCully KS, et al., "Production of arteriosclerosis by homocysteinemia," Am J Pathol, 61(1):1-11, 1970.
73. McNulty H, "Folate requirements for health in different population groups," Br J Biomed Sci 52:110-9, 1995. Review
74. McNulty H, "Folate requirements for health in women," Proc Nutr Soc, 56:291-303, 1997. Review
75. Mölgaard J, "Hyperhomocyst(e)inaemia: an independent risk factor for intermittent claudication, " J Int Med, 231:273-9, 1992.
76. Morrison HI, et al, "Relationship of dietary folate and vitamin B6 with coronary heart disease in women," JAMA, 280:417-9, 1998.
77. Morrison HI, "Serum folate and risk of fatal coronary heart disease," JAMA, 275:1893-6, 1996.
78. Murphy-Chutorian DR, et al., "Methionine Intolerance: A possible risk factor for coronary artery disease," J Am Coll Cardiol, 6:725-30, 1985.
79. Nygård O, et al., "Plasma homocysteine levels and mortality in patients with coronary artery disease," N Eng J Med, 337:230-6, 1997.
80. Nygård O, et al., "Total plasma homocysteine and cardiovascular risk profile. The Hordaland Homocysteine Study," JAMA, 274:1526-33, 1995.
81. O'Keefe CA, et al., "Controlled dietary folate affects folate status in nonpregant women," J Nutr, 125:2717-25, 1995.
82. Olszewski AJ, et al., "Fish oil decreases serum homocysteine in hyperlipemic men," Coron Artery Dis, 4(1):53-60, 1993.
83. Olszewski AJ, et al., "Homocysteine content of lipoproteins in hypercholesterolemia," Atherosclerosis, 88(1):61-8, 1991.
84. Olszewski AJ, et al., "Homocysteine metabolism and the oxidative modification of proteins and lipids," Free Radic Biol Med, 14(6):683-93, 1993.
85. Olszewski AJ, et al., "Plasma glucosamine and galactosamine in ischemic heart disease," Atherosclerosis, 82(1-2):75-83, 1990.
86. Olszewski AJ, et al., "Reduction of plasma lipid and homocysteine levels by pyridoxine, folate, cobalamin, choline, riboflavin, and troxerutin in atherosclerosis," Atherosclerosis, 75(1):1-6, 1989. See attached correction: Olszewski AJ, et al., "Homocysteine content of plasma in ischemic heart disease, the reducing effect of pyridoxine, folate, cobalamin, choline, riboflavin and troxerutin. Correction of a calculation error," Atherosclerosis, 88(1):97-8, 1991.
87. Omenn GS, et al., "Preventing coronary heart disease: B vitamins and homocysteine," Circulation, 97:421-4, 1998. Review
88. Pancharuniti N, et al., "Plasma homocyst(e)ine, folate, and vitamin B-12 concentration s and risk for early-onset coronary artery disease," Am J Clin Nutr, 59:940-8, 1994.
89. Peterson J and Spence J, "Vitamins and progression of atherosclerosis in hyper-homocyst(e)inaemia," Lancet, 351:263 (1998).
90. Pietrzik K and Brönstrup A, "The role of homocysteine, folate and other B-vitamins in the development of atherosclerosis," Arch Latinoam Nutr, 47:9-12, 1997. Review.
91. Pietrzik K and Brönstrup A, "Vitamins B12, B6 and folate as determinants of homocysteine concentration in the healthy population," Eur J Pediatr, 157 Suppl 2:S135-S138, 1998.
92. "Please More Folate," Public Health Report, 113:293, 1998.
93. Rath M and Niedzwiecki A, "Nutritional supplement program halts progression of early coronary atherosclerosis documented by Ultrafast computer tomography," Jour of Appl Nutr, 48:67-78 (1996).
94. Refsum H, et al., "Homocysteine and cardiovascular disease," Annu Rev Medicine, 49:31-62, 1998.
95. Ridker PM, et al., "Homocysteine and risk of cardiovascular disease among postmenopausal women," JAMA, 281:1817-1821, 1999.
96. Rimm EB, et al., "Folate and vitamin B6 from diet supplements in relation to risk of coronary heart disease among women," JAMA, 279:359-64, 1998.
97. Rinehart JF, et al., "Vitamin B6 deficiency in the Rhesus monkey," Am J Clin Nutrition, 4:318-28, 1956.
98. Robinson K, et al., "Low circulating folate and vitamin B6 concentrations: risk factors for stroke, peripheral vascular disease and coronary artery disease," Ciculation, 97:437-43, 1998.
99. Roe DA, "Drug-folate interrelationships: historical aspects and current concerns," Folic Acid Metabolism in Health and Disease, 277-287,1990.
100. Selhub J, et al., "Association between plasma homocysteine concentrations and extracranial carotid-artery stenosis," N Engl J Med, 332:286-91, 1995.
101. Selhub J, et al., "Vitamin status and intake as primary determinants of homocysteinemia in an elderly population," JAMA, 270:2693-2698, 1993.
102. Senti FR and Pilch SM, " Analysis of folate data from the Second National Health and Nutrition Examination Survey (NHANES II)," J Nutr, 115:1398-02, 1985.
103. Siri PW, et al., "Vitamins B6, B12, and folate: association with plasma total homocysteine and risk of atherosclerosis," J Am Coll Nutr, 17(5):435-41, 1998.
104. Stamler JS, et al., "Adverse vascular effects of homocysteine are modulated by endothelium-derived relaxing factor and related oxides of nitrogen," J Clin Invest, 91:308-318, 1993.
105. Stampfer MJ, et al., "A prospective study of plasma homocyst(e)ine and risk of myocardial infarction in US physicians," JAMA, 268:1992.
106. Swain RA and St. Clair L, "The role of folic acid in deficiency states and prevention of disease," J Fam Prac, 44:138-144, 1997.
107. Truswell AS and Kounnavong S, "Quantitative responses of serum folate to increasing intakes of folic acid in healthy women," Er J Clin Nutr, 51:839-45, 1997.
108. Tsai JC, "Promotion of vascular smooth muscle cell growth by homocysteine: A link to athersclerosis," Proc Nat'l Acad Sci, 91:6369-73, 1994.
109. Tucker KL, et al., "Dietary intake pattern relates to plasma folate and homocysteine concentrations in the Framingham Heart Study," J Nutr, 126:3025-3031, 1996.
110. Tzanakakis GN, et al., "Histopathological lesions produced by P. aeruginosa lipopolysaccharide in rats," J Exp Pathol, 4(4):199-211, 1989.
111. Tzanakakis GN, et al., "Primary extranodal non-Hodgkin's lymphoma of the extrahepatic biliary tract," R I Med J, 73(10):483-6, 1990.
112. Ubbink JB, et al., "The prevalence of homocysteinemia and hypercholesterolemia in angiographically defined coronary heart disease," Klin Wochen Schr, 69:527-534, 1991.
113. Ubbink JB, et al., "Vitamin B-12, vitamin B-6, and folate nutritional status in men with hyperhomocysteinemia," Am J Clin Nutr, 57:47-53, 1993.
114. Ueland PM and Refsum H, "Plasma homocysteine, a risk factor for vascular disease: Plasma levels in health, disease, and drug therapy," J Lab Clin Med, 114:473-501, 1989.
115. Verhoef P, et al., "Plasma total homocysteine, B vitamins, and risk of coronary atherosclerosis," Arterioscler Thromb Vasc Biol, 17:989-995, 1997.
116. von Eckardstein A, et al., "Effects of age, lipoproteins, and hemostatic parameters on the role of homocyst(e)inemia as a cardiovascular risk factor in men," Arterioscle Thromb, 14:460-64, 1994.
117. Voultilainen S, et al., "Association between elevated plasma total homocysteine and increased common carotid artery wall thickness," Ann Med, 30:3, 300-306, 1998.
118. Wakerlin GE, "Reducing the risk factors of coronary heart disease," J Rehabil, 32:21-2, 1966.
119. Wald NJ, et al., "Homocysteine and ischemic heart disease," Arch Int Med, 158:862-867, 1998.
120. Wilcken DEL and Wilcken B, "The pathogenesis of coronary artery disease," J Clin Invest, 57:1079-1082, 1976.
121. Wilcken DEL, Reddy SG and Gupta VJ, "Homocysteinenia, ischemic heart disease, and the carrier state for homocystinuria," Metabol, 32:363-70, 1983.
122. Wu LL, et al., "Plasma homocyst(e)ine as a risk factor for early familial coronary artery disease," Clin Chem, 404:552-61, 1994.