Are phytoestrogens harmful to the hormone balance?

Phytoestrogens, which are found in pulses such as lentils and soya products as well as in linseed, chickpeas and wholemeal products, are plant compounds that can have weak oestrogen-like effects (Thomson, Gray, & Rechzigl, 1998). However, these effects can vary depending on the quantity and individual reaction.

Studies have shown that soya protein consumption has no significant effect on testosterone levels in men. This is because soya protein is rich in phytoestrogens. A 2010 study definitively concluded that consuming 20 grams of soya protein daily for 57 days did not affect testosterone levels in men (Hamilton-Reeves et al., 2010). Other studies investigating the influence of soya products on hormone levels in men also found similar results (Messina, 2010).

Another study from 2017 definitively demonstrated that lentils, which also contain phytoestrogens, have no effect on hormone levels in men. The results were precise: consuming 56 grams of lentils daily for 28 days did not affect testosterone levels in men (Ciocci et al., 2017).

It is crucial to understand that while phytoestrogens are structurally similar to oestrogen, their effect on the body is significantly weaker than that of endogenous oestrogen (Harborne, Baxendale, & Mabry, 1994). It is, therefore, clear that the consumption of phytoestrogens cannot alter natural hormone levels in the body.

However, other clear health benefits are associated with eating pulses and other phytoestrogen-containing foods. Legumes are an excellent source of plant protein, fibre, vitamins and minerals (Messina, 2014). There is clear evidence that legume consumption reduces the risk of heart disease and cancer (Bazzano et al., 2001; Jenab et al., 2006).

However, it is essential to note that each body reacts differently, and it is always best to consult a specialist or nutritional expert if you have any questions or concerns. They will provide personalised advice and recommendations based on your specific needs.

Harborne, J. B., S. R. Baxendale, & Mabry, T. J. 1994. The flavonoids: the latest research since 1986. London: Chapman and Hall.

Hamilton-Reeves, J. M., Vazquez, G., Duval, S., Phipps, W. R., Kurzer, M. S., & Messina, M. (2010). Clinical studies have shown that soy protein and isoflavones do not affect reproductive hormones in men. This is the result of a meta-analysis. Fertility and Sterility, 94(3), 997-1007.

Thomson, C. A., Gray, M. A., & Rechzigl, R. (1998). This article will examine the mechanisms of action of phytoestrogens and cancer—Journal of Carcinogenesis, 17(6), R1-R9.

Bazzano, L. A., A. E. Thompson, Tees, M. S., Nguyen, C., Winham, D. M., and Toden, S. 2001. Consuming legumes is an effective way to improve diet quality and achieve weight loss in individuals attempting to lose weight in the PREMIER trial. Obesity Research, 9(6), 381–387.

Jenab, M., Ferrari, P., Slimani, N., Boffetta, P., & Riboli, E. (2006). There is clear epidemiological evidence that a high intake of fruits and vegetables protects against cancer. British Journal of Cancer, 94(3), 494-503.

Messina, M. 2010. There is no evidence that soy isoflavones have a feminising effect on men. This is the conclusion of a critical examination of the clinical evidence. Fertility and Sterility, 93(7), 2095-2104.

Messina, M. 2014. Soy and Health Update: A Critical Evaluation of the Clinical and Epidemiologic Literature. Nutrients, 6(12), 5291–5331.

Ciocci, M. C., Longobardi, S., Stuppia, L., Spina, R., & Vecchia, L. (2017). No evidence exists that lentil (Lens culinaris and Medik.) consumption affects sex hormone levels in healthy men. Journal of functional foods, 36, 348-352.


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