A combination of soy isoflavone supplementation and exercise
improves lipid profiles and protects antioxidant defense-systems against
exercise-induced oxidative stress in ovariectomized rats
Affiliations: Department of Food and Nutrition, Brain Korea 21
Project, Yonsei University College of Human Ecology, Seoul, Republic of
Korea | Department of Sport Science, Sungkyunkwan University,
Suwon, Republic of Korea
Note: [] Address for correspondence: Prof. Sun Yoon, Department of Food
and Nutrition, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, Korea
120-749. Tel.: +82 2 2123 3119; Fax: +82 2 2123 3115; E-mail: snkim@yonsei.ac.kr
Abstract: Menopause is often accompanied with weight gain, metabolic lipid
abnormalities, and oxidative stress. In this study, we investigated the
combined effects of exercise and soy isoflavone supplemention on the lipid
profiles and antioxidant capacities of ovariectomized rats. Twenty-five female
Sprague-Dawley rats were divided into 5 groups: sham-operated, ovariectomized
(OVX), OVX with exercise (OVX+EX), OVX with soy isoflavone
supplementation (OVX+ISO), and OVX with both soy
isoflavones and exercise (OVX+ISO+EX). After 12 weeks of intervention, antioxidant status was evaluated in
collected blood samples by the ferric reducing ability of plasma (FRAP),
glutathione (GSH) content, and sodium oxide dismutase (SOD) activity. DNA
damage in the lymphocytes was determined using alkaline single-cell gel
electrophoresis (the Comet assay). Although there were no significant
differences in weight gain and food intake, weight gain was lower in
OVX+EX, OVX+ISO, and OVX+ISO+EX than in OVX.
OVX+EX, OVX+ISO, and OVX+ ISO+EX showed a significant
decrease in total cholesterol, triglycerides, and LDL-cholesterol compared to
OVX. The soy isoflavone supplemented group had significantly increased FRAP
values and GSH contents in contrast to no changes in the exercised group,
whereas exercise markedly increased SOD activity and
H_{2}O_{2}-induced DNA tail length and
tail moment. Exercise with soy isoflavone supplementation significantly
increased FRAP values and had no difference on SOD activity, including DNA
damage. These results demonstrate that a combined treatment of moderate
exercise and soy isoflavone supplementation could exert a beneficial effect on
weight control and lipid profiles, and offer protection from exercise-induced
oxidative stress in postmenopausal women.
