Relationship of Dietary Folate and Vitamin B6With Coronary Heart Disease in Women

To the Editor.—The otherwise excellent article by Dr Rimm et al¹ on the epidemiology of CHD among women left out a major confounding variable—decreased food vitamin B₁₂absorption with increasing age^2- 5 —and thereby drew the erroneous conclusion that intake of folate and vitamin B₆above the current recommended dietary allowance may be important in the primary prevention of CHD among women. Coronary heart disease among women is primarily a postmenopausal event. Much more important is intake of a daily supplement of vitamin B₁₂without added vitamin C and iron (which destroy much of the vitamin B₁₂when the 3 dissolve together in the stomach).^2- 3 Extra folic acid suppresses the appearance of megaloblastic anemia, allowing neuropsychiatric damage from vitamin B₁₂deficiency to progress to irreversibility,^2,5 and hyperhomocysteinemia from vitamin B₁₂deficiency to eventually override the added folate.⁵ Incidentally, low serum folate levels in vitamin B₁₂deficiency are due to enterocyte megaloblastosis,⁵ and low red blood cell folate levels in vitamin B₁₂deficiency occur because vitamin B₁₂is necessary for folate transport into, and retention by, erythrocytes.