The effect of an increased intake of vegetables and fruit on weight loss, blood pressure and antioxidant defense in subjects with sleep related breathing disorders

Abstract

Objective: To assess the effect of an increased consumption of vegetables and fruit on body weight, risk factors for cardiovascular disease (CVD) and antioxidant defense in obese patients with sleep-related breathing disorders (SRBD). Design: Randomized, controlled trial of an intervention to increase the intake of vegetables to 400g/day and fruit to 300g/day. Dietary intake was calculated from a food frequency questionnaire. Antioxidant status was assessed with the ferric-reducing/antioxidant power (FRAP) assay. Plasma carotenoids were biomarkers for the intake of vegetables and fruit. Setting: A hospital clinic preventing risk factors for CVD. Subjects: Subjects were 103 men and 35 women with a body mass index of 36.7 ± 5.8 kg/m2 of which 57 (86%) in the control and 68 (94%) in the intervention group completed the study. Intervention: Group-based behavioral program during 3 months. Results: The mean between group differences in body weight was -2.0% (95% CI -3.6, -0.5), P < 0.0001. The mean between group difference in systolic and diastolic blood pressure (BP) was -7.1 mm Hg (95% CI: -11.6, -2.6), P = 0.0022 and -3.9mm Hg (95% CI: -7.0, 0.9), P = 0.0120, respectively. The mean change in daily intake of vegetables and fruit was 12g (95% CI: -33, 57) and -4g (95% CI: -79, 71) versus 245g (95% CI: -194, 296) and 248g (95% CI: -176, 320) in the control and intervention groups, respectively. This was reflected in higher concentrations of α-carotene and β-carotene. No change in FRAP was seen. In a multiple regression analysis the change in intake of vegetables was a significant contributor (Radj2 = 0.073 (95% CI: 0.019, 0.214)) to the change in weight. Conclusion: Targeted dietary advice to increase the intake of vegetables and fruit among subjects with SRBD contributed to weight reduction and reduced systolic and diastolic BP, but had no effect on antioxidant defense measured with FRAP.