Multivitamin and mineral supplement did not alter the antioxidant capacityin plasma of healthy young men and women

Diets high in fruit and vegetable have been associated with a reduced risk of several cancers and cardiovascular disease. Antioxidant vitamins have be en suggested to be responsible. The objective of the study was to determine whether there is an association between plasma antioxidant capacity and pl asma antioxidant concentrations and whether a 3 week vitamin/ mineral suppl ement will enhance the plasma antioxidant capacity in 57 healthy UCLA medic al students. The plasma antioxidant capacity was determined before and afte r 3 weeks of a daily vitamin/ mineral supplement which provided 440 TCT of alpha-tocopherol (alpha-T), 22,500 IU of beta-carotene (beta-C) and 620 mg of ascorbic acid. The anti-oxidant capacity was determined by HPLC measurem ent of thiobarbituric acid reacting substances (TBARS) after exposing the p lasma to oxidative stress generated by 2,2-azobis(2-amidinopropane) hydroch loride (AAPH) for 4 hours at 37 degrees C. Plasma alpha-T and beta-C were m easured by HPLC. There was no association between plasma antioxidant capaci ty before supplementation and plasma alpha-T or beta-C concentrations. Mult ivitamin/ multimineral supplementation did not enhance the antioxidant capa city. More specific markers of oxidative stress may be needed and future st udies with longer supplementation periods are warranted. (C) 2000 Elsevier Science Inc.