Serum urate determines antioxidant capacity in middle-aged men - a controlled, randomized diet and exercise intervention study

Abstract

Objectives: To study whether advice on diet and/or exercise, given in order to reduce cardiovascular risk factors in middle-aged men, affects the intake of antioxidants, urate concentration and the total antioxidant capacity in serum.

Design: A 6-month randomized controlled intervention study.

Setting: Primary Health Care in Sollentuna, Stockholm, and the Department of Medicine, Karolinska Hospital, Stockholm, Sweden.

Subjects: One hundred and fifty-eight healthy men (46.2 +/- 5.0 years) with moderately raised cardiovascular risk factors.

Interventions: Advice on diet (D, n = 40), exercise (E, n = 39), diet and exercise (DE, n = 39) and a control group (C, n = 39).

Main outcome measures: Dietary intake, exercise habits, S-urate and the antioxidant capacity in serum (TAOC).

Results: After 6 months, changes in dietary and exercise habits were seen in all three intervention groups and favourable effects were seen on BMI, waist circumference, blood pressure, S-cholesterol and fasting insulin. The intake of alpha-tocopherol was decreased in groups D and E (P < 0.01) and beta-carotene was increased in groups D and DE (P < 0.01). In group DE, the intake of vitamin C was increased (P < 0.05). S-urate was reduced in group D from 345 to 325 micromol L-1 (P < 0.05). No significant changes in TAOC were seen in any group. S-urate and TAOC were correlated (r = 0. 58, P < 0.001) and S-urate was correlated to several parameters in the metabolic syndrome.

Conclusion: Favourable changes in diet and exercise reduced several cardiovascular risk factors but did not affect the total antioxidant capacity in serum. S-urate was a strong determinant of the antioxidant capacity.