The Effects of Soy Isoflavones to Improve the Metabolism of Glucose and Lipids

The Study of the Effects of Soy Isoflavones on the Metabolism of Glucose and Lipids in Postmenopausal Chinese Women With Impaired Glucose Regulation

Chinese Nutrition Society, Danone Institute International, Department of Health of Guangdong Province

Many studies showed that soy foods or soy isoflavones can lower the risk of cardiovascular disease (CVD), osteoporosis and some cancers, but few human studies assessed effects of purified isoflavone components (genistein and daidzein) on glucose metabolism. This double-blinded, randomized, placebo-controlled trial will examine the effects of purified genistein and daidzein on glucose metabolism in prediabetic or diabetic women. One hundred and eighty eligible women age 30-70 years(without any treatment of diabetic drugs) will be recruited and randomly allocated into the following three arms: Placebo (10g isolated soy protein, ISP); Genistein (10g ISP + 50mg genistein); Daidzein (10g ISP + 50mg daidzein) per day for 6 mo. Fasting glucose, lipids, insulin, inflammation marks and post-load for glucose and insulin will be determined at 0, 3th, and 6th month. Changes in these indices will be compared among the three groups.

Subjects were Chinese adult women, age 30-70 year, with an FG concentration ranging from 5.6 to 7.0 mmol/L or 2-h PG concentration ranging from 7.8-11.0 mmol/L or with newly diagnosed diabetes not requiring medication treatment according to a doctor's suggestion or participants did not willing to take medication themselves, and managed their diabetes just with a stable diet and exercise. Women were excluded if they had a history of coronary heart disease, stoke, thyroid disease, severe liver, lung, or gastrointestinal tract diseases; were currently or in the past 8 weeks used hypoglycemic or lipid-lowering or weight-reduction agents; were occurrence of diabetic complications; use of hormone replacement therapy; allergy to soy;were long-term antibiotics users.

genistein, daidzein, impaired glucose regulation, glucose metabolism, lipids metabolism, inflammation, women

values were from 75g glucose oral glucose tolerance test and caculated as (6th month value-baseline value)/baseline value*100%

HOMA-IR was calculated with the homeostasis model assessment for insulin resistance,and it is caculated as the following equation: HOMA-IR=FIns×FG/22.5, where FIns represents fasting insulin in microunits per milliliter, and FG is in millimoles per liter. The percentage change was caculated as (6th month value-baseline value)/baseline value*100%

QUICKI is the abbreviation of Quantitative Insulin Sensitivity Check Index,and it is a marker to evaluate insulin sensitivity in HOMA model.It is calculated by using the following equation: 1/(logFIns +logFG),where FIns represents fasting insulin in microunits per milliliter, and FG is in millimoles per liter. The percentage change was caculated as (6th month value-baseline value)/baseline value*100%

Inclusion Criteria: Chinese women aged 30-70 y Fasting glucose >=5.6 mmol/l; post-load glucose >=7.8 mmol/l Exclusion Criteria: Diabetes renal diseases Confirmed CVD, chronic liver,kidney diseases,Thyroid disease Medications affecting glucose or lipid metabolism