Moses M Suzman MD, a respected internist and neurologist in South Africa, suspected that a pandemic deficiency of B6 was the prime cause of heart attacks. So beginning in 1950, his mostly white patients took two 50 mg tablets of B6 a day with meals.

Lifestyle made no difference, he found. Except for adding a daily B-complex after 1972, he urged no other change in their diet, supplements or lifestyle. They ate sensibly, exercised or smoked if they felt like it.

Over a stretch of 45 years, his tens of thousands of current and former pre-cardiac patients had far fewer heart problems than would have been expected.

Heart patients who had had a heart attack or chest pain, or refused bypass surgery, took 200 mg of B6 every day, plus folic acid, magnesium and vitamin E. Later Dr Suzman added vitamin C, selenium and other nutrients. The heart patients were also instructed to eat a semi-vegetarian diet.

After a few weeks, they were able to be weaned off heart medicines, and eventually their arterial clogging regressed. Many of his hundreds and hundreds of former heart patients enjoyed "youthful" health for decades. Moreover, Dr Suzman knew of no coronary artery spasm, cardiac arrest or stroke among any of his patients even among stressed hypertensives.

In 1962, clinician/researcher John Marion Ellis began to use B6 to treat carpal tunnel syndrome (CTS) (Ann NY Acad Sci 1990; 85: 302-20). Among Dr Ellis's patients taking B6-again, eating Western processed diets few had heart attacks or underwent bypass surgery. And those few had symptoms of advanced vitamin B6 deficiency: CTS, diabetes, tingling and edema in fingers and hands, and more.

No doubt, some of Dr Ellis's patients took other supplements as well and improved their diets, exercised or quit smoking. But regardless, those who took 50 to 200 mg of vitamin B6 a day for decades had 73 per cent fewer chest pains and heart attacks than others (Ann NY Acad Sci, 1990; 85: 302-20).

None of Suzman's or Ellis's tens of thousands of patients complained of any side effects.

But how does vitamin B6 prevent heart attacks? In 1969, research pathologist Kilmer S McCully proposed the homocysteine theory of arteriosclerosis (Amer J Path, 1969; 56:111-128). The toxic, sulphur containing amino acid homocysteine (HC) results from normal metabolism of the amino acid methionine which is abundant in red meat, milk and milk products. About one person in seven inherits a tendency to high HC.

It's been proposed that even slight elevation puts one at risk of a heart attack without high cholesterol, blood pressure, smoking and other conventional risk factors (J Clin Pathol, 1964; 17: 427-37). HC promotes the tiny clots that initiate arterial damage (Ann Clin & Lab Sci, 1991; 19: 225-37), and the catastrophic ones that precipitate most heart attacks and strokes (Lancet June 13, 1981).

Twenty five years later, evidence supporting McCully's prescient theory has been flooding in. One study showed that men with three clogged coronary arteries have higher HC than men with one clogged artery (Klin Woch, 1991; 69: 527-534). It has also been shown that doctors with high HC have three times more heart attacks, far more strokes, and much more arterial disease in the legs than doctors with low HC (Canad J Cardiol, 1989; 17: X-XI). We also know that fish oil prevents arterial damage and thrombosis, largely by lowering HC (Coronary Artery Dis, 1993; 4: 53-60).

B6 makes possible the conversion of HC into useful, generally non-toxic cystathionine, and on into cysteine, which is critically important in normal brain function and in the detoxification of the hundreds of chemicals you are exposed to every day.

B6 in adequate amounts also prevents the tiny clots that start arterial damage, and can prevent catastrophic clotting (Lancet 1981; June 12: 1299-1300).

Provoked by erratic stress, mast cells on the surfaces of blood vessels emit histamine, a potent stimulator of cell division. Histamine leads to plaque formation and inflammation (Exp Cell Res, 1992; 199: 279-91).

Treatment of human diabetics with either antihistamines (Invest Ophthalm Visual Sci , 1991; 32: 1289) or vitamin B6 (Biochem Biophys Res Comm, 1991; 179: 615-19) has been shown to lessen vascular leakage and stem retinal degeneration, suggesting that B6 also functions as an antihistamine.

B6 deserves a prominent place in our personalized heart prediction, health building program. But it shouldn't be seen as a magic bullet. It best shields the heart and performs its many other functions as one element of a sensible diet and supplements program, in consultation with a qualified practitioner.

!AJoseph Hattersley

Joseph Hattersley is co-author of a forthcoming book on preventing heart attacks.