Soy, or soya bean, is a type of leguminous plant that primary grows in eastern parts of Asia. Soy is marketed as a protein source for men and women alike. The growing popularity of this industrial product stems from the fact that it’s cheap to produce. Food manufacturers use this as a protein “filler” to top up protein counts in food products. Numerous studies have shown that soy is an inferior source of protein and can have negative effects on men.
According to Ahn-Jarvis et al. (2015), soy protein alters the physiological responses in men and disrupts estrogen levels. The active ingredient in soy, isoflavones, behaves like estrogen. Estrogen, erroneously connotated as a female-exclusive hormone, plays an important role is the male body’s hormone equilibrium (Thrane, Paulsen, Orcutt and Krieger 2016). However, elevated levels of estrogen stunts muscle development, lowers testosterone, increases cortisol levels, causes gynecomastia, decreases libido, and even reduces sperm production.
A study in 2007 provided male test subjects over the age of 18 two scoops (56g) of soy protein powder a day for 28 days. The subjects’ testosterone levels decreased 19% during their use of soy protein powder and induced estrogen activity. Their testosterone levels increased 2 weeks after discontinuing soy consumption. In 2014, a study done by Neacsu, Fyfe, Horgan and Johnstone found that excessive soy consumption led to infertility and erectile dysfunction. 99 male test subjects being treated for infertility were found to have been on a continuous soy diet for three months. Their consumption of soy protein on daily basis were exposing them to unanticipated and highly adverse effects of high levels of estrogen in their body. Similarly, Asian men, such as those from China, India, Japan and Indonesia, consume higher amounts of soy compared to American men. It was found in a 2014 study (Horgervorst 2014) that as a result, these Asian men are 10% more likely to experience erectile dysfunction.
In addition to hormonal effects, serious long-term health conditions and illnesses can be attributed to high soy consumption. This includes thyroid irregularity, bladder cancer, prostate cancer and dementia, particularly those over 65. Men in Indonesia and China with tofu in their diets were found to have lower memory functions and an increased risk of dementia (Horgervorst 2014).
As a protein source, soy has a slower protein synthesis than whey, casein and pea proteins and contain “anti-nutrients” like lectin and protein inhibitors that block the digestion and absorption of nutrients. Not all protein sources are equal and some forms of protein are better than others. For those who take fitness seriously, using soy proteins could hinder or reverse progress made at the gym. Consumption of high-quality proteins like meat and whey in favour of lower-quality proteins like soy can lead to a reduction of muscle mass or even atrophy.
Soy has been marketed as a “superfood” but there is controversy over this product. While there can be some health benefits for women when it comes to soy, males should take more caution. The prevalence of soy as an ingredient in everyday foods will lead to excessive consumption. Manufacturers are routinely hiding soy in foods such as bread, meat products with filler (hamburgers) protein bars (Cliff bars), infant formula and other common foods. To avoid soy and its detrimental effects start checking labels as an important step in maintaining male virility and health.
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Ahn-Jarvis, J., Clinton, S. K., Grainger, E. M., Riedl, K., Schwartz, S. J., Lee, M. L. T., … & Vodovotz, Y. (2015). Isoflavone pharmacokinetics and metabolism after consumption of a standardized soy and soy-almond bread in men with asymptomatic prostate cancer. Cancer Prevention Research, canprevres-0465.
Dwyer, J. T., Goldin, B. R., Saul, N., Gualtieri, L., Barakat, S., & Adlercreutz, H. (1994). Tofu and soy drinks contain phytoestrogens. Journal of the American Dietetic Association, 94(7), 739-743
Elbardisi, H., Majzoub, A., Al Said, S., Al Rumaihi, K., El Ansari, W., Alattar, A., & Arafa, M. (2018). Geographical differences in semen characteristics of 13 892 infertile
Gotoh, N., Graham, A., Nikl, E., & Darley-Usmar, V. M. (1993). Inhibition of glutathione synthesis increases the toxicity of oxidized low-density lipoprotein to human monocytes and macrophages. Biochemical Journal, 296(1), 151-154.
Goodin, S., Shen, F., Shih, W. J., Dave, N., Kane, M. P., Medina, P., Lambert, G.H., Aisner, J. & Dipaola, R. S. (2007). Clinical and Biological Activity of Soy Protein Powder Supplementation in Healthy Male Volunteers. Cancer Epidemiology Biomarkers & Prevention, 16(4), 829-833. doi:10.1158/1055-9965.epi-06-0882men. Arab Journal of Urology, 16(1), 3-9
Hajos, G., Gelencsér, E., Grant, G., Bardocz, S., Sakhri, M., Duguid, T. J., Newman, A.M.,Pusztai, A. (1996). Effect of proteolytic modification and methionine enrichment on the nutritional value of soya albumins for rats. The Journal of Nutritional Biochemistry,7(9), 481-487. doi:10.1016/0955-2863(96)00093-9
Hogervorst, E. (2014). Different types of soy products and their possible benefit and risk associated with dementia in China and Indonesia. Lecture presented at OMICS International Conference on Alzheimer’s Disease and Dementia, Valencia, Spain.
Huang, Y., Pan, L., Xia, X., Feng, Y., Jiang, C., & Cui, Y. (2008). Long-Term Effects of Phytoestrogen Daidzein on Penile Cavernosal Structures in Adult Rats. Urology,72(1), 220-224. doi:10.1016/j.urology.2007.11.06
Kraemer, W. J., Solomon-Hill, G., Volk, B. M., Kupchak, B. R., Looney, D. P., Dunn-Lewis, C., … & Maresh, C. M. (2013). The effects of soy and whey protein supplementation on acute hormonal responses to resistance exercise in men. Journal of the American College of Nutrition, 32(1), 66-74
Lao, M., Harnisch, B. A., & Honig, S. C. (2018). Environmental Issues in Maintaining Reproductive Health. In Bioenvironmental Issues Affecting Men’s Reproductive and Sexual Health, 175-189
Lesinski, G. B., Reville, P. K., Mace, T. A., Young, G. S., Ahn-Jarvis, J., Thomas-Ahner, J., … & Schwartz, S. J. (2015). Consumption of soy isoflavone enriched bread in men with prostate cancer is associated with reduced pro-inflammatory cytokines and immunosuppressive cells. Cancer Prevention Research, 1-29
Moundras, C., Remesy, C., Levrat, M. A., & Demigne, C. (1995). Methionine deficiency in rats fed soy protein induces hypercholesterolemia and potentiates lipoprotein susceptibility to peroxidation. Metabolism, 44(9), 1146-1152
Neacsu, M., Fyfe, C., Horgan, G., & Johnstone, A. M. (2014). Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial–. The American journal of clinical nutrition, 100(2), 548-558
Sutton, M., Hunn, C., Summers-Colquitt, R. B., Chen, S. H., Kavoussi, S. K., Kavoussi, K. M., & Kavoussi, P. K. (2018). Promescent Has a Cytotoxic Impact on Fresh Human Sperm In Vitro. Urology, 114, 95-98
Thrane, M., Paulsen, P. V., Orcutt, M. W., & Krieger, T. M. (2016). Soy protein: Impacts, production, and applications. Sustainable protein sources,23-45
van Die, M. D., Bone, K. M., Williams, S. G., & Pirotta, M. V. (2014). Soy and soy isoflavones in prostate cancer: a systematic review and meta‐analysis of randomized controlled trials. BJU international, 113(5b), E119-E130