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Soy protein supplementation improved testosterone levels in men with diabetes, low testosterone
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CHICAGO — Men with type 2 diabetes and low testosterone levels who were given supplementation with soy protein and phytoestrogens showed significantly improved testosterone levels compared with those given soy protein alone.
According to data presented in a press conference and a poster at the joint meeting of the International Congress of Endocrinology and the Endocrine Society by Thozhukat Sathyapalan, MD, an endocrinologist researcher at Hull York Medical School, there was also a significant improvement in glycemic control, triglyceride and C-reactive protein levels in a group given the soy protein/phytoestrogen combination.
Thozhukat Sathyapalan
“With the use of estrogen and soy, glucose parameters, levels of inflammation, blood pressure improved and there was a beneficial effect on diabetes control,” Sathyapalan said.
As part of a randomized, double-blind, parallel study, 210 men with type 2 diabetes and low testosterone were given cereal bars containing 7.5 mg soy protein and 33 mg phytoestrogens (n=100) or bars containing 7.5 mg soy protein and no phytoestrogens (n=100). Participants were between the ages of 55 and 70 years, had obesity (average BMI=32 kg/m2), had diabetes and showed borderline low-testosterone levels of ≤12 nmol/L. Participants consumed the bars twice daily for approximately 90 days, and were asked not to eat any additional foods that contained soy so as not to influence study results, according to a press release. Primary outcome for the study was an adjustment in testosterone levels; secondary outcome was a modification in cardiovascular risk factors.
According to abstract data, there was a significant increase in serum total testosterone in those who received soy and phytoestrogens (9.83±0.21 vs. 11.34±0.36 nmol/L; P<.01) and in those who just received soy (9.22±0.23 vs. 10.33±0.3 nmol/L; P<.01).
Improvements in diabetes, cardiometabolic risk
There was a significant reduction in HbA1c (52.71±1.19 vs. 50.16±1.26 mmol/mol; P=.01), fasting glucose levels (7.93±0.21 vs. 6.45±0.15 mmol/L; P<.01), and fasting insulin rates (19.78±1.72 vs. 8.98±0.63 µIU/mL; P<.01) in the soy and phytoestrogen group that was not seen in those on soy alone. Modifications in weight were not seen in either group.
Changes to cardiovascular risk factors were also noted. The soy/phytoestrogen combination group showed significantly reduced triglycerides (1.67±0.09 vs. 0.87±0.04 mmol/L; P<.01) and C-reactive protein (3.13±0.46 vs. 0.69±0.11; P<.01), a marker that indicates risk for cardiac events. Diastolic blood pressure was reduced significantly for both groups (soy/phytoestrogen: 80.86±0.99 vs. 78.22 mmHg; P=.03; soy alone: 80.01 vs. 78.06 mmHg; P=.05). There were no changes in systolic blood pressure for either group.
For More Information: Sathyapalan T. Poster SAT-0367. Presented at: The joint meeting of the International Congress of Endocrinology and the Endocrine Society; June 21-23, 2014; Chicago.
Disclosures: Sathyapalan reports no relevant financial disclosures. The study received funding from the Food Standards Agency, which is responsible for food safety in the United Kingdom.