Isoflavone supplementation

PATISAUL H B, DiNDO M, WHITTEN p L, YOUNG L J (2001) Soy isoflavone Supplements antagonize reproductive behavior and oestrogen receptor alpha- and beta-dependent gene expression in the brain. Endocrinol. 142 2946-52. 

HSU 0 s, SHEN w w, HSUEH, Y M and YEH s L (2001) Soy isoflavone supplementation in postmenopausal women. Effects on plasma lipids, antioxidant enzye activities and bone density. JReprod Med 46, 221-6. 

SETCHELL K D R, BROWN N M, DESAI P, ZIMMER-NECHEMIAS L, WOLFE B E, BRASHEAR W T, KIRSCHNER A s, CASSIDY A and HEUBI J E (2001) BioavailabUity of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements. JNutr 131, 1362S-75S. 

Since 1999, when the Food and Drug Administration allowed the first health claim for soy-fortified foods in the USA, there has been a large increase in the sales of food products claiming to contain soy isoflavones. At the same time, over-the-counter supplements have become widely available. However, concerns have been raised about the real health benefits of such supplements in the absence of adequate information about bioavailability, pharmacokinetics and safety. To fill this gap, an extensive study on pure isoflavones and commercial soy isoflavone supplements has recently been carried out (Setchell et al, 2001). A selection of 31 commercially available supplements showed a wide variation in isoflavone composition and in the amount provided by one tablet. Furthermore, a lower isoflavone content, with respect to the claimed levels, has been observed in almost 50% of the analysed products. In one case, no isoflavones at all could be detected (Setchell et al, 2001). 

One study directly evaluated semen and testicular endpoints in men consuming soy phytoestrogens. Mitchell et al. (2001) reported a study of 14 young men (18 to 35 years old) who consumed 40 mg per day of soy isoflavones (in a tablet form) for two months. The subjects were followed for two months before and three months after taking the supplement. The isoflavone supplement did not change testicular or ejaculate volume, or sperm concentration, count, or motility. 

Baber, R. J., Templeman, C., Morton, T., Kelly, G.E. and West, L. (1999). Randomised placebo-controlled trial of an isoflavone supplement and menopausal symptom in women, Climacteric, 2, 85-92. 

Isoflavonoids Soybeans, tofu, isoflavone supplements Linear (+) THAP, DHB 318... 

Setchell, K.D., Brown, N.M., Desai, P., Zimmer-Nechemias, L., Wolfe, B.E., Brashear, W.T., Kirschner, A.S., Cassidy, A., and Heubi, J.E., Bioavailability of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements, J. Nutr., 131, 1362S, 2001. 

Consumption of soy foods (providing 60mg/day isoflavones) for 12 weeks by postmenopausal women has been found to significantly decrease clinical risk factors for osteoporosis (short-term markers of bone turnover) including decreased urinary M-telopeptide excretion (bone resorption marker) and increased serum osteocalcin (bone formation marker). Furthermore, consumption of a soy isoflavone supplement containing 61.8 mg of isoflavones for 4 weeks by postmenopausal Japanese women significantly decreased excretion of bone resorption markers. ... 

Consumption of soy foods for 10 weeks (100 mg/day isoflavones) has been reported to improve human memory in young healthy adults and consumption of a soy isoflavone supplement for 12 weeks (60 mg/day isoflavones) to improve cognitive function in postmenopausal women. By contrast, consumption of soy protein (99mg isoflavones/day) for 12... 

Although toxicity from isoflavones may arise from their action as alternative substrates for the enzyme thyroid peroxidase and people in southeast Asia would be protected by the dietary inclusion of iodine-rich seaweed products, a recent study has shown that isoflavone supplements do not affect thyroid function in iodine-replete postmenopausal women. Considerations of the safety of soy isoflavones is an area of great interest in relation to their potential benefits to human health and has recently been comprehensively reviewed. ... 

Djuric Z, Chen G, Doerge DR, Heilbrun LK, Kucuk O. Effect of soy isoflavone supplementation on markers of oxidative stress in men and women. Cancer Lett. 172, 1-6, 2001. 

Uesugi T, Fukui Y, Yamori Y. Beneficial effects of soybean isoflavone supplementation on bone metabolism and serum lipids in postmenopausal Japanese women a four-week study. J. Am. Coll Nutr. 21, 97-102, 2002. 

Bruce B, Messina M, Spiller GA. Isoflavone supplements do not affect thyroid function in iodine replete postmenopausal women. J. Med. Food 6, 309-316, 2003. 

Gardner C, Chatterjee L, Morris J, Franke AA. 2008. Effects of isoflavone supplements versus soy foods on blood concentrations of genistein and daidzein. J Nutr Biochem. 

Davis, J. N., Kucuk, O., Djuric, Z., Sarkar, F. H. (2001). Soy isoflavone supplementation in healthy men prevents NF-kappa B activation by TNF-alpha in blood lymphocytes. Free Rad. Biol. Med., 30, 1293-1302. 

Messina, M. C.L. Hughes. The efficacy of soyfoods and soybean isoflavone supplements for alleviating menopausal symptoms is positively related to initial hot flash frequency, J. Medicinal Foods 2003, 6, 1-11. 

Hale, G. M. Paul-Labrador J.H. Dwyer C.N. Merz. Isoflavone supplementation and endothelial function in menopausal women. Clin. Endocrinol (Orf) 2002, 56, 693—701. 

Ho, S.C. Y.M. Chen S.S. Ho J.L. Woo. Soy isoflavone supplementation and fasting serum glucose and lipid profile among postmenopausal Chinese women A double-blind, randomized, placebo-controlled trial. Menopause 1Wf7, 14, 905—912. 

Williamson-Hughes, RS. B.D. Flickinger M.J. Messina M.W Empie. Isoflavone supplements containing predominantly genistein reduce hot flash symptoms A critical review of published studies. Menopause 2QQ(>, 13, 831-839. 

So far, reported trials concerned the effect of soy food or soy isoflavone supplements on thyroid hormone levels. 

Isoflavones may be found in small amounts in soy-based infant formulas [10]. Isoflavones are found in whole soybeans and products including tofu, tempeh, and soy milk. Isoflavones are classified as both phytoestrogens (plant estrogens) and selective estrogen receptor modnlators. The phytoestrogenic effects of isoflavones have led to the use of soy foods and isoflavone supplements as alternatives to conventional hormone therapy. However, studies have found no long-term complications associated with isoflavones in infants fed soy-based formulas [10,17]. 

From an epidemiological study, the intake of soy isoflavone supplements also could decrease the risk of the breast eaneer [10,11]. 

NCT01028001 Phase II trial of preoperative soy isoflavone supplementation and molecular markers in the prevention of head and neck squamous carcinoma... 

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