Soy isoflavone supplementation and fasting serum glucose... : Menopause (original) (raw)
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Soy isoflavone supplementation and fasting serum glucose and lipid profile among postmenopausal Chinese women
A double-blind, randomized, placebo-controlled trial
Ho, Suzanne C. PhD1,2; Chen, Yu-ming PhD1,5; Ho, Susan S.S. PhD3; Woo, Jean L.F. MD4
From the 1Department of Community and Family Medicine, The Chinese University of Hong Kong, Hong Kong SAR; 2Centre of Research and Promotion of Women's Health, School of Public Health, The Chinese University of Hong Kong, Hong Kong SAR; 3School of Pharmacy, The Chinese University of Hong Kong, Hong Kong SAR; 4Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR; and 5Department of Medical Statistical and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, PR China.
Received August 18, 2006; revised and accepted November 2, 2006.
Funding/support: The study was supported by the Epidemiology Development Fund of the Department of Community and Family Medicine of the Chinese University of Hong Kong.
Financial disclosure: None reported.
Address correspondence to: Suzanne C. Ho, PhD, Department of Community and Family Medicine, The Chinese University of Hong Kong, 4/F School of Public Health, Prince of Wales Hospital, Shatin, N.T., Hong Kong. E-mail: [email protected].
Objective:
Long-term effects of soy-derived isoflavones on lipids remain uncertain, and few data are available on their effects on glycemic control. We examined the effects of isolated soy germ isoflavones on the changes in fasting glucose (FG) and lipids.
Design:
A double-blind, randomized, placebo-controlled trial was conducted in 203 postmenopausal Chinese women aged 48 to 62 years. They were randomly assigned to receive daily doses of 500 mg calcium, and 0 mg isoflavones (placebo, n = 67), 40 mg isoflavones (n = 68), and 80 mg isoflavones (n = 68). Serum FG, triglycerides, high-density lipoprotein, low-density lipoprotein, total cholesterol, and lipoprotein cholesterol were measured at baseline and 1 year after treatment. The primary data analysis was performed on the 203 randomized women according to the intent-to-treat principle. The last value carried forward was used for any missing data at follow-up.
Results:
We observed moderate but significant favorable effects of soy isoflavones on the changes (P = 0.012) and percentage of changes (P = 0.031) in FG (analysis of variance). The 1-year mean (SD) differences of FG changes were −5.2 (−9.4 to −1.0) mg/dL (P = 0.010) and −3.3 (−7.5 to 0.9) mg/dL (P = 0.18) in the 40- and 80-mg isoflavone groups compared with the placebo group. We also noted a significant interaction between the treatment and baseline FG on the changes in FG (P = 0.004). The isoflavone effects were much more significant in women with baseline FG 100 mg/dL or more than in those with FG less than 90 mg/dL. We observed little effect of soy isoflavones on changes in serum lipids among the treatment groups.
Conclusions:
One-year of soy isoflavone supplementation might have a favorable effect on FG in women, but has no significant effect on serum lipids.
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