Folic Acid, Vitamin B-12 and Heart Disease

Dateline: 12/27/98

As discussed in last week's article, Homocysteine (Hcy)is degraded by enzymes that depend on Vitamins for their action. Vitamin B-6, Folic Acid and Vitamin B-12 have all been found essential in removing Hcy from the blood, and so are protective factors for heart disease.

The role of Folic Acid and Vitamin B-12

To achieve a safe level of Homocysteine (below 9 micro-mol/L), dietary modification alone is not enough. Supplementation of 400 micrograms of Folic Acid produces an average lowering of Hcy by 5 micro-mol/L.

Dr.William Castle, who discovered Vitamin B-12, had in his initial lectures declared "Never give folic acid without giving Vitamin B-12 first". The reason is that, in people with low levels of Vitamin B-12, the addition of folic acid could exacerbate nerve injury, which might be potentially irreversible. Although such a happening is rare, it is recommended that 200 to 1000 micrograms of Vitamin B-12 be included with every 400 micrograms of Folic Acid supplements.

Some critics might well ask : Is the evidence conclusive ?

The answer is NO. It is important to remember that "associations are not effects". In a memorable study conducted to assess the role of beta carotene in reducing heart disease and lung cancer, the CARET study surprisingly found that beta carotene actually INCREASED the incidence of lung cancer.

There are still some questions that remain:

• the relation between Folic Acid, Vitamin B-12 and B-6 to Hcy levels
• the relation between Hcy levels and cardiovascular risk
• the best way to demonstrate and record risk reduction for individuals and populations

To resolve these queries, specially designed prospective trials are underway, including the VISP (Vitamins in Stroke Prevention) trial and a large study of 30,000 patients seen by general practitioners in Norway.

So what should a clinician do today ?

Dr.Gilbert Omenn, one of the pioneers in Homocysteine research, says

"On balance, we believe that the reduction of Hcy levels of above 15 micro-mol/L to below 10, is similar to the impact expected from a reduction in total cholesterol levels from 275 to 189 mg/dl"

Considering this, and the relationship between folic acid, homocysteine and cardiovascular risk, there is strong evidence for the potential benefits of increasing folic acid intake on a population wide basis.

* Everyone should consume atleast 400 micrograms of folic acid daily.

* Screening for homocysteine levels in the blood would

1. help assess individual risk profiles
2. target efforts to adhere to therapy
3. allow recommendation of increased dosages of folic acid in select cases

* No recommendation is possible, based on evidence available, on Vitamin B-6.

* Supplementation of 200 to 1000 micrograms of Vitamin B-12 in folic acid capsules is also recommended. This dose is enough to ensure adequate absorption, and might protect older patients with various degrees of Vitamin B-12 deficiency.

The Future

Already companies have begun to fortify cereal with folic acid and Vitamin B-12 supplements. Many more functional foods are in the offing. Life science refers to a swirl of diverse biomedical advances that are beginning to jell. Biotech will speed the jelling. Research might even allow bio-engineers to slice out genes that make chemicals that prevent heart disease, and then splice them into wheat, corn and other grains to create a cornucopia of heart healthy foods.

And then we can all eat to our heart's content.

But until then, don't forget to take your daily Vitamin pill !

And have a very Happy New Year - 1999