Exercise and Phytoestrogens: Effect on Factors Predisposing to Cardiovascular Disease(CVD) in Postmenopausal Women

Summary

Menopause is characterized by a decrease of estrogen and progesterone levels and is associated with various changes in body composition, including an accumulation of total fat mass, a relocation of adiposity to the abdomen, deterioration of plasma lipid profile, increased risk of type 2 diabetes, and increased oxidative stress. Taken together, these changes increase the risk of developing cardiovascular disease (CVD).

Physical activity and hormone-replacement therapy (HRT) have been shown to act in synergy to improve total fat mass in postmenopausal (PM) women. Because the progesterone component of HRT has been associated with an increased CVD risk in older women with a family history of CVD, the use of HRT has become controversial. As a result, a large decrease of the use of HRT in the community has been observed and postmenopausal women (PM) have developed interest in alternative therapies. Among the possibilities, phytoestrogens have shown beneficial effects on menopausal symptoms and plasma lipids. Phytoestrogens are structurally and functionally similar to estradiol (the major estrogen in humans) but found only in plants such as soybean isoflavones. They do not exert any effect on breast cancer or/and endometrial tissue.

AIMS To examine the effects of phytoestrogens, exercise and the combination of both on lean body mass, total fat mass, visceral fat, blood lipid profile, oxidative stress markers, antioxidant system, glucose metabolism, and sex-hormone levels in obese PM women.

HYPOTHESES Women undergoing a combination of phytoestrogen treatment and an exercise program will display a greater increase in lean body mass, decrease in total and visceral fat mass, improvements in blood lipid profile, decrease in oxidative stress markers, increase in antioxidant system, improvement in glucose metabolism, and increase in sex-hormone levels than those submitted to any or one of the treatments.

A total of 120 women will be recruited. There will be 4 groups (30 women/group) undergoing exercise or not and supplemented with phytoestrogens or a placebo. The intervention is planned to last 12 mo. Key variables will be measured at baseline, and after 6 and 12 mo of intervention.

Three weekly 1h-sessions of exercise will be held on 3 non-consecutive days. The phytoestrogen supplements will consist of 70 mg/d of soy isoflavones taken as 4 caps/day.

Conditions

• Overweight

Interventions

BEHAVIORAL

Placebo + exercise

Placebo: Non-active capsules of the same size and appearance than phytoestrogens capsules will be used as a placebo (same posology, i.e. 4 caps/day) Exercise intervention: Three weekly 1h-sessions will be held on 3 non-consecutive days. Each session comprises a total of 60 min of aerobic exercise (on an ergometer device) and resistance exercise (with elastic bands, free weights, exercise ball, etc.), and a 5-min cool down. Cues regarding exercise intensity will be offered to maintain intensity in a range of 60 to 80% of maximal heart rate (with the use of a target pulse, etc.). The exercise sessions will be led by a physical activity specialist.

DIETARY_SUPPLEMENT

Phytoestrogens without exercise

Phytoestrogens: The phytoestrogen supplements will consist of 70 mg/day of soy isoflavones taken as 4 caps/day. More specifically, the daily dose of isoflavones contains 44 mg of diadzein, 16 mg of glycitein and 10 mg of genestein extracted from natural soy. Without exercise: participants will be asked to do only their usual activities without being involved in any kind of structured exercise sessions.

OTHER

Phytoestrogens + exercise

Phytoestrogens: The phytoestrogen supplements will consist of 70 mg/day of soy isoflavones taken as 4 caps/day. More specifically, the daily dose of isoflavones contains 44 mg of diadzein, 16 mg of glycitein and 10 mg of genestein extracted from natural soy. Exercise intervention: Three weekly 1h-sessions will be held on 3 non-consecutive days. Each session comprises a total of 60 min of aerobic exercise (on an ergometer device) and resistance exercise (with elastic bands, free weights, exercise ball, etc.), and a 5-min cool down. Cues regarding exercise intensity will be offered to maintain intensity in a range of 60 to 80% of maximal heart rate (with the use of a target pulse, etc.). The exercise sessions will be led by a physical activity specialist.

Sponsors & Collaborators

• Canadian Institutes of Health Research (CIHR)

  collaborator OTHER_GOV

• Université de Sherbrooke

  lead OTHER

Principal Investigators

• Isabelle J Dionne, Ph.D. · Université de Sherbrooke

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

FACTORIAL

Eligibility

Min Age

50 Years

Max Age

70 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2009-01-31

Primary Completion

2012-11-30

Completion

2012-11-30

Countries

• Canada

Study Locations