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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #57187
Title: B-CAROTENE SUPPLEMENTATION INCREASES ANTIOXIDANT CAPACITY OF PLASMA IN OLDER WOMEN

Author
item MEYDANI MOHSEN - TUFTS-HNRCA
item MARTIN ANTONIO - TUFTS-HNRCA
item RIBAYA-MERCADO J - TUFTS-HNRCA
item GONG JUXIAN - TUFTS-HNRCA
item BLUMBERG JEFFREY - TUFTS-HNRCA
item RUSSELL ROBERT M - TUFTS-HNRCA

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: It has been suggested that above average intakes of carotenoids, which are forms of vitamin A, are associated with a lower risk of coronary heart disease. In this study, twelve healthy elderly women supplemented their usual diet with either 90 mg beta-carotene (the most active of the carotenoid variety of vitamin A) or a placebo capsule daily for a three-week period. This beta-carotene supplementation, which is not achievable through diet alone, significantly increased the amount of beta-carotene in the blood without affecting vitamin E or other antioxidant levels which help to prevent damage to other nutrients by oxygen. This data suggests that beta-carotene may play an important role in the overall antioxidant defense system of blood. When blood samples from the subjects were exposed in a test tube to a chemical that effects the same damage as oxygen, blood from beta-carotene-supplemented subjects was more resistant to oxygen damage than subjects who took the placebo. Therefore, the beneficial effect of carotenoid supplementation on decreasing the risk of coronary heart disease may be due in part by increasing body antioxidant capacity and by acting in combination with other antioxidants.

Technical Abstract: The antioxidant effect of dietary beta-carotene supplementation on the peroxidation potential of plasma was investigated in a random- ized double-blind, placebo-controlled study. Twelve healthy women (62-80 yrs) supplemented their usual daily diet with 90 mg beta- carotene (n=6) or placebo (n=6) capsules for 3 wk. Plasma levels of beta-carotene, alpha- and gamma-tocopherol, ascorbate, urate, bili- rubin and in vitro production of phosphatidylcholine hydroperoxides (PC-OOH) and utilization of plasma antioxidants in the presence of 50 mmol/L 2,2YU-azobis (2-aminopropane) hydrochloride (AAPH), a free radical generator, at 37Y!C were measured before and after dietary treatment. Plasma beta-carotene increased from 0.76+/-0.16 to 6.45+/-1.16 Y5mol/L (p<0.05) in supplemented but not placebo treated subjects. The plasma level of other antioxidants did not change significantly in either group. Beta-carotene supplement- ation did not affect basal levels of plasma PC-OOH as measured by HPLC postcolumn chemiluminescence, but did affect AAPH-induced production of PC-OOH. Before supplementation, the induction period of plasma PC-OOH production was 2.4+/-0.4 hrs with levels reaching 5.39+/-1.50 micromol/L after 6 hrs incubation. After supplement- ation, the induction period increased significantly to 4.2+/-0.4 hrs with a with a lower PC-OOH production of 2.16+/-0.90 micromol/L after 6 hrs. In this system, plasma ascorbate concentrations were depleted first, followed by loss of bilirubin and alpha-tocopherol and then by the sequential loss of gamma-tocopherol, urate, and B-carotene. These results indicate that B- carotene supplementation increases plasma antioxidant capacity of women.