phytoestrogens and Hyperglycemia

Isoflavones found in soy products have a chemical structure similar to estrogen, leading to concerns of an adverse estrogenic effect in men, particularly in those with type 2 diabetes mellitus (T2DM) who have low testosterone levels due to hypogonadism.. The primary outcome was change in total testosterone levels. The secondary outcomes were the changes in glycemia and cardiovascular risk markers.. This was a randomized double-blind parallel study.. This study occurred in a secondary care setting in United Kingdom.. Two hundred men with T2DM and a total testosterone level ≤12 nmol/L were included.. Fifteen grams of soy protein with 66 mg of isoflavones (SPI) or 15 g soy protein alone without isoflavones (SP) daily as snack bars for 3 months were administered.. There was no change in either total testosterone or in absolute free testosterone levels with either SPI or SP. There was an increase in thyrotropin (TSH) and reduction in free thyroxine (fT4; P < 0.01) after SPI supplementation. Glycemic control improved with a significant reduction in hemoglobin A1c (-4.19 [7.29] mmol/mol, P < 0.01) and homeostasis model of assessment - insulin resistance after SPI. Cardiovascular risk improved with a reduction in triglycerides, C-reactive protein, and diastolic blood pressure (DBP; P < 0.05) with SPI vs SP supplementation. There was a 6% improvement in 10-year coronary heart disease risk after 3 months of SPI supplementation. Endothelial function improved with both SPI and SP supplementation (P < 0.01), with an increased reactive hyperemia index that was greater for the SPI group (P < 0.05).. Testosterone levels were unchanged and there was a substantial improvement in glycaemia and cardiovascular risk markers with SPI compared with SP alone over 3 months. There was also a substantial increase in TSH and a reduction in fT4.

Topics: Aged; Anthropometry; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Dietary Proteins; Double-Blind Method; Humans; Hyperglycemia; Hypogonadism; Isoflavones; Male; Middle Aged; Phytoestrogens; Soybean Proteins; Testosterone

Topics: Animals; Blood Glucose; Diabetes Mellitus, Type 1; Feces; Female; Gastrointestinal Microbiome; Gastrointestinal Tract; Genistein; Glucose Intolerance; Homeostasis; Hyperglycemia; Insulin; Male; Mice; Mice, Inbred NOD; Phytoestrogens; Sequence Analysis, DNA

While peripheral insulin resistance is common during obesity and aging in mice and people, the progression to type 2 diabetes (T2D) is largely due to loss of β-cell mass and function through apoptosis. We recently reported that genistein, a soy derived isoflavone, can improve glycemic control and β-cell function in insulin-deficient diabetic mice. However, whether it can prevent β-cell loss and diabetes in T2D mice is unknown. Our current study aimed to investigate the effect of dietary supplemented genistein in a nongenetic T2D mouse model. Nongenetic, middle-aged obese diabetic mice were generated by high fat diet and a low dose of streptozotocin injection. The effect of dietary supplementation of genistein on glycemic control and β-cell mass and function was determined. Dietary intake of genistein (250 mg·kg(-1) diet) improved hyperglycemia, glucose tolerance, and blood insulin level in obese diabetic mice, whereas it did not affect body weight gain, food intake, fat deposit, plasma lipid profile, and peripheral insulin sensitivity. Genistein increased the number of insulin-positive β-cell in islets, promoted islet β-cell survival, and preserved islet mass. In conclusion, dietary intake of genistein could prevent T2D via a direct protective action on β-cells without alteration of periphery insulin sensitivity.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Dietary Supplements; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Genistein; Glucose Tolerance Test; Hyperglycemia; Insulin; Insulin-Secreting Cells; Lipids; Male; Mice; Mice, Inbred C57BL; Phytoestrogens