Vitamin B6 and coronary artery disease. Epidemiological observations and case studies

The finding of low plasma pyridoxal-5'-phosphate levels in patients suffering from myocardial infarction has been construed as possible evidence for the pathogenetic role that vitamin B6 deficiency may play in causing premature ischaemic heart disease. However, the presence of normal plasma pyridoxal-5'-phosphate levels in patients with angiographic evidence of coronary artery narrowing but with no previous infarctions prompted the investigation of possible short-term alterations in plasma pyridoxal-5'-phosphate levels during the acute phase of myocardial infarction. In the follow-up of 30 patients with acute myocardial infarction, all of them showed a continuous decrease of approximately 45% in plasma pyridoxal-5'-phosphate levels during the acute phase. These levels subsequently returned back to normal before discharge from hospital. A large number of volunteers from an ethnic group known to have a very low incidence of ischaemic heart disease were found to have both significantly lower total cholesterol and plasma pyridoxal-5'-phosphate levels than a Caucasian group in the same geographic area which is known to have a high incidence of ischaemic heart disease. These findings therefore do not support the contention that vitamin B6 deficiency may be a risk index for ischaemic heart disease.