COFFEE CAUSE HEART ATTACKS?
Report #7001; 1/18/97
Why do some studies show that coffee causes heart attacks, while others show that it does not? A recent study in the American Journal of Clinical Nutrition shows us why (1).
Drinking filtered, decaffeinated coffee does not increase your chances of suffering a heart attacks, while drinking large amounts of unfiltered coffee do (2). Most of the studies from Europe show an association between drinking coffee and heart attacks, while most in the United States show no association (3). Americans filter their coffee which removes a factor that raise cholesterol. Caffeine raises blood pressure, which increases a person's chances of suffering a heart attack (4). In the most recent study, Norwegian scientists showed that drinking large amounts of coffee that contains caffeine raises blood levels of homocysteine, which causes heart attacks (1). Normally your body makes protein from amino acids that you eat and your body forms. One amino acid called cysteine is manufactured by your body by a series of chemicals reactions. If you lack the vitamins B12, folic acid or pyridoxine, your body cannot make adequate amounts of cysteine and accumulates large amounts of homocysteine in its place (5,6). Homocysteine causes heart attacks by punching holes in arteries, starting plaque formation and then causing clots to form in the plaques (7,8,9). Lack of folic acid is more likely than B12 or pyridoxine to be the cause of heart attacks (7). Fruits, leafy green vegetables and beans are rich sources of the vitamin, folic acid. So, if you must drink coffee, drink fewer than 6 cups a day, drink it filtered and decaffeinated and eat lots of fruits, vegetables, whole grains and beans or take vitamin pills.
By Gabe Mirkin, M.D., for CBS Radio News
1) American Journal of Clinical Nutrition. January, 1997.
2) Katan M. American Journal of Clinical Nutrition, January, 1995.
3) Coffee consumption: Relationship to blood lipids in middle-aged women. International Journal of Epidemiology. 1994 (June); 23(3): 523-527.
4) BH Sung, TL Whitsett, WR Lovallo, M Alabsi, GA Pincomb, MF Wilson. Prolonged increase in blood pressure by a single oral dose of caffeine in mildly hypertensive men. American Journal of Hypertension 1994 (Aug); 7(8): 755-758.
5) JAMA October 4, 1995 (More than 10% of heart attacks are caused by lack of folic acid.) You need at least 400 micrograms of folic acid a day to prevent homocysteine from accumulating in your bloodstream.
6) 6-week period of vitamin supplementation (1.0 mg folic acid, 10 mg pyridoxine, 0.05 mg cyanocobalamin. JB Ubbink, A Vandermerwe, WJH Vermaak, R Delport. Clinical Investigator 1993 (Dec); 71(12): 993-998.
7) P Verhoef, MJ Stampfer, JE Buring, JM Gaziano, RH Allen, SP Stabler, RD Reynolds, FJ Kok, CH Hennekens, WC Willett. Homocysteine metabolism and risk of myocardial infarction: Relation with vitamins B-6, B-12, and folate. American Journal of Epidemiology 143: 9 (MAY 1 1996): 845-859.
8) Selhub J et al. Association between plasma homocysteine concentrations and extracranial carotid-artery stenosis. NEJM 1995 (Feb).
9) J Blacher, G Montalescot, A Ankri, B Chadefauxvekemans, R Benzidia, Y Grosgogeat, P Kamoun, D Thomas. Hyperhomocysteinaemia in coronary artery disease: Results of a study of 102 patients. Archives Des Maladies du Coeur et Des Vaisseaux 89: 10 (OCT 1996): 1241-1246.