Elsevier

Nutrition

Volume 27, Issues 7–8, July–August 2011, Pages 859-862
Nutrition

International ward rounds
Hypogonadism and erectile dysfunction associated with soy product consumption

https://doi.org/10.1016/j.nut.2010.10.018Get rights and content

Abstract

Previous research has focused on the beneficial effects of soy and its active ingredients, isoflavones. For instance, soy consumption has been associated with lower cardiovascular and breast cancer risks. However, the number of reports demonstrating adverse effects of isoflavones due to their estrogenlike properties has increased. We present the case of a 19-y-old type 1 diabetic but otherwise healthy man with sudden onset of loss of libido and erectile dysfunction after the ingestion of large quantities of soy-based products in a vegan-style diet. Blood levels of free and total testosterone and dehydroepiandrosterone (DHEA) were taken at the initial presentation for examination and continuously monitored up to 2 y after discontinuation of the vegan diet. Blood concentrations of free and total testosterone were initially decreased, whereas DHEA was increased. These parameters normalized within 1 y after cessation of the vegan diet. Normalization of testosterone and DHEA levels was paralleled by a constant improvement of symptoms; full sexual function was regained 1 y after cessation of the vegan diet. This case indicates that soy product consumption is related to hypogonadism and erectile dysfunction. To the best of our knowledge, this is the first report of a combination of decreased free testosterone and increased DHEA blood concentrations after consuming a soy-rich diet. Hence, this case emphasizes the impact of isoflavones in the regulation of sex hormones and associated physical alterations.

Introduction

During the past two decades, accumulating evidence has linked soy consumption to beneficial health effects. Most of these health effects are related to the presence of isoflavones in soybeans [1]. The isoflavones genistein and daidzein are structurally and functionally similar to 17-β-estradiol, but with weaker bioactivity than estradiol [2]. Genistein and daidzein bind to the estrogen receptor-α and are therefore also known as phytoestrogens [3], [4]. Animal studies have shown that these isoflavones possess mixed estrogen receptor agonist/antagonist properties [5]. Isoflavones have been reported to lower cholesterol blood concentration in men [6], [7]. Furthermore, isoflavones are assumed to inhibit bone loss and to alleviate vasomotor symptoms, also referred to as hot flashes, in postmenopausal women [7], [8]. Some clinical evidence has linked isoflavones to a decreased risk of coronary heart disease [1], [9]. Furthermore, there are epidemiologic studies showing that isoflavone intake can lower the risk of breast cancer [10], [11]. However, some studies on the positive health effects of soy bean consumption are equivocal and reports of adverse effects of isoflavones related to their estrogenlike properties have been published [1], [12], [13]. Furthermore, the recent finding of reproductive toxicity of isoflavones in rats has amplified the discussion of estrogenic effects of isoflavones [14]. There are only infrequent reports of symptoms of feminizing such as gynecomastia related to soy product consumption [15]. Some investigators have concluded that isoflavones do not exert feminizing effects on men even at high intake levels [16]. The objective of this study is to document a case of hypogonadism and erectile dysfunction related to soy product ingestion and to review the current literature.

Section snippets

Case report

A 19-y-old male pre-med student with a history of type 1 diabetes mellitus presented to our clinic with complete loss of libido and erectile dysfunction that had begun suddenly 12 mo previously. Previously, he had been in good health. He stated a heterosexual preference and he had been sexually active and had sufficient libido. The patient denied any testicular trauma, history of orchitis, or undescended testicles. He had no history of androgen abuse or any hormonal medication. He denied any

Discussion

The symptoms of hypogonadism and erectile dysfunction and the hormonal findings of decreased free and percentage of free testosterone and increased DHEA levels in the present patient are related to the intake of 360 mg of isoflavones per day over 1 y. In comparison, the average dietary isoflavone intake in Western countries is as low as 2 mg/d [18]. The constellation of decreased free testosterone and increased DHEA indicates that isoflavones may cause an insufficient production of

References (20)

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