Many women with PCOS also suffer from low thyroid function, compounding their problems with excess weight. Several ladies have emailed me regarding the use of soy lecithin to obtain DCI from dietary sources with concerns over whether it will exacerbate hypothyroid conditions.
Soy products are widely consumed in our society in modern times, especially as food additives to increase protein content or to emulsify other ingredients.
A large body of research into the effects of soy protein has found that it interferes with thyroid hormone production and function and can even cause goitres in healthy children and adults when consumed on a regular basis.
Soy lecithin is an oil component of soybeans – it has no protein in it. The oil based components of soy should not pose any problems for thyroid function, as the soy isoflavones genistein and daidzein which inhibit thyroid peroxidase-catalyzed reactions essential to thyroid hormone synthesis are only found in the protein part of soy.
More Information:
Divi RL, Chang HC, Doerge DR, Anti-thyroid isoflavones from soybean: isolation, characterization, mechanisms of action. Biochem Pharmacol 1997 Nov 15;54(10):1087-96 www.ncbi.nlm.nih.gov/pubmed/9464451
Sathyapalan T et al, The Effect of Soy Phytoestrogen Supplementation on Thyroid Status and Cardiovascular Risk Markers in Patients with Subclinical Hypothyroidism: A Randomized, Double-Blind, Crossover Study, J Clin Endocrinol Metab, 2011 Feb 16; May 1, 2011 vol. 96 no. 5 1442-1449
http://jcem.endojournals.org/content/96/5/1442.abstract
Gilchrist JM et al, Ultrasonographic patterns of reproductive organs in infants fed soy formula: comparisons to infants fed breast milk and milk formula. J Pediatr. 2010 Feb;156(2):215-20. Brain Lang. 2012 Jan;120(1):27-41. Epub 2011 Sep 1.
Pivik RT et al, Effects of diet on early stage cortical perception and discrimination of syllables differing in voice-onset time: A longitudinal ERP study in 3 and 6month old infants. Brain Lang. 2012 Jan;120(1):27-41
Dinsdale EC et al, Early life exposure to isoflavones adversely affects reproductive health in first but not second generation female CD-1 mice. J Nutr. 2011 Nov;141(11):1996-2002.
Bar-El DS et al, Soy as an endocrine disruptor: cause for caution? Isr Med Assoc J. 2010 Nov;12(11):684-6.