Dr. Kilmer McCully Was Right!

Vitamins May Help
Prevent Heart Disease in Women

By Dr. Gail Valentine

ead all about it in the February 4, 1998 issue of the Journal of the American Medical Association (JAMA).Vitamin B6 and folate may prevent coronary heart disease.1 For readers of Life Enhancement, the benefits of these B vitamin dietary supplements as well as other vitamins, hormones, antioxidants, amino acids, and so on - in amounts which you can't get from food - are known and have been known for years. And in some instances, for decades. Pioneer researcher Kilmer McCully, M.D. [see Heart Disease is a Vitamin Deficiency - February 1998] did his original research on the artery damaging (atherosclerotic) amino acid homocysteine nearly 30 years ago! Yet as per JAMA's leading comment on the latest study of this subject . . .

    Although the separate pieces of the pathway that connect folate and vitamin B6, to coronary artery disease via homocysteine metabolism have been well studied in both laboratory and epidemiologic investigations, this article is the first to examine the entire pathway in an epidemiologic study. [Bold added by writer.]

Men Too!

Another study on vitamin B6 and folate examined the levels of homocysteine in two groups of European men and women: 750 with blockages in blood vessels of their heart, brain, and legs and 800 healthy controls.1 What they found was that "normal" RDA levels of vitamin B6 and folic acid play a role in preventing heart disease and strokes.

Those who had the lowest levels of the two B vitamins had nearly twice the risk of heart disease and stroke. Curiously, the levels of homocysteine, linked in previous studies to heart disease and strokes, were independent of whether blockage was present suggesting that vitamin B6 and folate may have additional mechanisms that prevent atherosclerosis.

Dr. Killian Robinson, a cardiologist at the Cleveland Clinic and the leader of the study said, "There's something else going on that vitamin B6 is doing."

  1. Robinson, K., et al. 1998. Low circulating folate and vitamin B6 concentrations: Risk factors for stroke, peripheral vascular disease, and coronary artery disease. Journal of the American Heart Association (Feb. 10):1.

Technically speaking, JAMA may be "first" in this regard, but why weren't they first 30, 20 or even 10 years ago, when the earlier work was done? Yet, as the editorial note goes on, the findings of this latest study need further research because there are limitations to epidemiologic studies. Sure, more studies are important, but let's not wait until we're all dead. At least they're not saying, "don't take supplementary vitamins until we give you the go ahead," a typical posture of other leading scientific journals. The authors of the JAMA study have published similar sentiments before in some of these same journals. It is noteworthy that these publications often have been as quick to deny the benefits of a nutrient as they have been eager to support the breakthrough of a new drug.

The study, conducted by seasoned Harvard researchers (some of whom publicly admit to their own use of supplementary vitamins2), analyzed the results of a detailed food frequency questionnaire completed by 80,082 women from the Nurse's Health Study taken in 1980. None of the women had a prior history of cardiovascular disease, cancer, hypercholesterolemia, or diabetes. At the conclusion of the study, 14 years after it began, 658 of the women had heart attacks and 281 had died from heart disease. 

Data gathered included the women's eating habits allowing the researchers to analyze the kind of B vitamins in their diets, both for those unaffected by heart disease and those who experienced heart attacks or suffered death.

In their conclusions, the scientists found a direct correlation between the levels of folate consumed and heart disease and with the levels of vitamin B6 consumed and heart disease. Summarily, for every 200 mcg of folate consumed on a daily basis, heart disease risk dropped by 11 percent while for every 2 mg increase in vitamin B6 consumed on a daily basis, heart disease risk fell by 17 percent.

Leader of the study, Eric B. Rimm, ScD, says that in order to cut heart disease, "daily vitamin intake of folate and vitamin B6 ought to be higher than the current recommended daily allowance (RDA)." The RDA has been a matter of controversy in recent years  especially among scientists that receive funding from the Federal trough and some RDAs, including that of folate has been lowered! Nevertheless, the RDAs for women are 180 mcg for folate and 1.6 mg for B6. The national averages for consumption of folate and B6 are 225 mcg/d and 1.5 mg/d respectively. In the study the median amounts consumed by the highest quintile (there were five divisions) were 696 mcg/d for folate and 4.6 mg for B6. The benefits of each of these two B vitamins, considered separately and together, was linear up to and including the amounts of the highest quintile. This study means that the higher the intake of folate and B6, the greater the cardiovascular benefit.

Folate and Vitamin B6
Where to Get Them

Some nutritional supplements contain abundant amounts of folate and vitamin B6. In the best of these formulations, the quantities of these nutrients are determined by a number of scientific factors including a detailed knowledge of the intermediate metabolic pathways of the body, thoughtful long-term studies of all the principal scientific literature concerning safety, bioavailabilty, relationships and other pertinent material. More of a particular ingredient is not necessarily better. To the contrary, there are optimal levels and limits or ranges for everything contained in these quality multivitamin, multimineral, antioxidant formulations. They contain in the daily recommended serving size 700–800 mcg of folate and 36–75 mg of B6.

Given the eating habits of most Americans, these levels, stated above, are not frequently obtained. For the subjects of the study (nurses), by far the largest contributor to the totals for both folate and B6 was multivitamin supplements. It is difficult to obtain adequate levels of vitamins from foods. Of the total folate in the average diet 26% came from supplements and just 8% from the next highest contributing foods, cold cereal. For B6, the breakdown of sources was not mentioned. However, among those women not taking supplements the largest source of B6 was beef.

When the consumption of folate for the nurses in the highest quintile (fifth) was compared to that of those in the lowest quintile, there was a reduced risk of heart disease by 47%. The comparable reduced risk for the nurses taking the highest amount (compared to the lowest amount) of vitamin B6 was 51%. For those whose intake of folate and B6 was about double the RDA, notes researcher Rimm, "risk for heart disease was almost cut in half."

Kilmer McCully, M.D., was the real hero behind the heart disease/homocysteine theory so it is a credit to JAMA that they chose to publish an editorial by Dr. McCully in the same issue of their journal along with the folate and B6 study.3 Dr. McCully writes that, "the study by Rimm and previous studies support the validity of the homocysteine theory of atherosclerosis." If, in his opinion, the findings of the current study are embraced and if intervention through taking supplements and fortification (adding more of these nutrients to foods) is encouraged, "the decline in US cardiovascular mortality and morbidity will continue."

References

  1. Rimm EB, Willett WC, Hu FB, Sampson L, Colditz GA, Manson JE, Hennekens C, Stampfer MJ. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA. 1998;279:359-364.
  2. "So if you ask Eric Rimm, the lead investigator on the Harvard study of male health professionals, whether the government should advise the public to take Vitamin E, he will say no. But if you ask him if he takes it himself, you will get a different answer. 'My grandfather had a heart attack when he was very young,' Rimm said, "and I take Vitamin E in addition to having a healthy diet and not smoking." Stolberg S. The Rags to Riches Story of E. LA Times June 16, 1993:1.
  3. McCully KS. Homocysteine, folate, vitamin B6, and cardiovascular disease. JAMA. 1998;279:392-393.

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