Soy protein improves cardiovascular risk in subclinical hypothyroidism : a randomized double-blinded crossover study

Sathyapalan, Thozhukat; Javed, Zeeshan; Rigby, Alan S.; Kilpatrick, Eric S.; Atkin, Stephen L.

Abstract

© 2017 Endocrine Society. Background: Soy protein with isoflavones appears to have an adverse effect on thyroid function, but it is not known whether it is the protein or isoflavone component that is deleterious. The effect of isoflavone-free soy on thyroid function was determined in patients with subclinical hypothyroidism, with a secondary aim of assessing its effect on cardiovascular risk indices. Methods: This was a randomized, double-blind, crossover study involving 80 patients with subclinical (compensated) hypothyroidism. Patients were randomly assigned to either isolated soy (isoflavone-free) protein (SP) or casein protein (CP) supplementation for 8 weeks, washed out for 8 weeks, and then crossed over for a further 8-week period. Results: Thyroid function was unaffected by either a SP or CP. There were significant decreases in fasting glucose (4.760.6 vs 5.561.4, P < 0.01), insulin resistance (3.3±3.0 vs 3.8±3.4, P = 0.05), total cholesterol (4.4 ± 0.9 vs 5.3 ± 1.2, P < 0.01), triglycerides (0.9 ± 0.5 vs 1.7 ± 0.9, P < 0.1), and highly sensitive C-reactive protein (hsCRP; 0.8 ± 0.7 vs 2.6 ± 2.8, P < 0.01) in the SP group compared with the CP group. Blood pressure, low-density lipoprotein, and high-density lipoprotein remained unchanged in both groups. Conclusion: SP alone had no effect on thyroid function in patients with subclinical hypothyroidism and resulted in a significant reduction in fasting glucose, insulin resistance, total cholesterol, triglycerides, and hsCRP compared with CP.

Citation

Sathyapalan, T., Javed, Z., Rigby, A. S., Kilpatrick, E. S., & Atkin, S. L. (2017). Soy protein improves cardiovascular risk in subclinical hypothyroidism : a randomized double-blinded crossover study. Journal of the Endocrine Society, 1(5), 423-430. https://doi.org/10.1210/js.2016-1068

• Journal Article Type: Article
• Acceptance Date: Mar 27, 2017
• Online Publication Date: Apr 3, 2017
• Publication Date: May 1, 2017
• Deposit Date: Sep 28, 2017
• Publicly Available Date: Sep 28, 2017
• Journal: Journal of the Endocrine Society
• Electronic ISSN: 2472-1972
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 1
• Issue: 5
• Pages: 423-430
• DOI: https://doi.org/10.1210/js.2016-1068
• Keywords: Cardiovascular risk; Soy protein; Isoflavone; Subclinical hypothyroidism
• Public URL: https://hull-repository.worktribe.com/output/455295
• Publisher URL: https://academic.oup.com/jes/article-lookup/doi/10.1210/js.2016-1068
• Additional Information: Copy of article: Thozhukat Sathyapalan, Zeeshan Javed, Alan S. Rigby, Eric S. Kilpatrick, Stephen L. Atkin; Soy Protein Improves Cardiovascular Risk in Subclinical Hypothyroidism: A Randomized Double-Blinded Crossover Study, Journal of the Endocrine Society, Volume 1, Issue 5, 1 May 2017, Pages 423–430, https://doi.org/10.1210/js.2016-1068