Urinary phytoestrogen levels related to idiopathic male infertility in Chinese men

Abstract

Phytoestrogens (PEs) are naturally occurring chemical constituents of certain plants. The internal PE exposures, mainly from diet, vary among different populations and in different regions due to various eating habits. To investigate the potential relationship between urinary PE levels and idiopathic male infertility and semen quality in Chinese adult males, 608 idiopathic infertile men and 469 fertile controls were recruited by eligibility screening procedures. Individual exposure to PEs was measured using UPLC-MS/MS as spot urinary concentrations of 6 PEs (daidzein, DAI; equol, EQU; genistein, GEN; naringenin, NAR; coumestrol, COU; and secoisolariciresinol, SEC), which were adjusted with urinary creatinine (CR). Semen quality was assessed by sperm concentration, number per ejaculum and motility. We found that exposures to DAI, GEN and SEC were significantly associated with idiopathic male infertility (P-value for trend=0.036; 0.002; and 0.0001, respectively), while these exposures had stronger association with infertile subjects with at least one abnormal semen parameter than those with all normal semen parameters. Exposures to DAI, GEN and SEC were also related to idiopathic male infertility with abnormal sperm concentration, number per ejaculum and motility (P-value for trend<0.05), while these exposures had stronger association with the infertile men with abnormal sperm number per ejaculum. These findings provide the evidence that PE exposures are related to male reproductive function and raise a public health concern because that exposure to PEs is ubiquitous in China.

Higher Urinary Lignan Concentrations in Women but Not Men Are Positively Associated with Shorter Time to Pregnancy

“…The lack of association we observed between urinary concentrations of phytoestrogens from male partners and TTP in this study may be due to the low in vitro affinity of individual phytoestrogens, which may make it more unlikely to exert a significant estrogenic activity among men. Moreover, effects of phytoestrogens on semen quality have been inconsistent, with studies typically only demonstrating effects on specific semenquality variables, if at all (10)(11)(12)(13).…”

“…Vegetable protein intake has also been shown to be associated with reduced ovulatory infertility (9), although phytoestrogen intake was not directly measured in this study. Studies in men have been conflicting, with some reports of effects on specific semen quality variables (10) or idiopathic male infertility (11), and others reporting no associations (12,13). However, to our knowledge, no previous studies have evaluated effects on couple fecundity as measured by time to pregnancy (TTP) 9 .…”

Nutrition in Human Fertility

“…On the other hand, Chavarro and colleagues examined the relation between intake of soy and semen parameters among 99 male partners of couples seeking fertility treatment and found that higher intake of soy foods was associated with lower sperm concentration [ 197 ]. In agreement with these fi ndings, a 2013 study of 609 idiopathic infertile men and 469 fertile controls in China by Xia and colleagues reported that urinary levels of isofl avones were related to lower sperm concentration, total count and motility, and higher odds of idiopathic male infertility [ 198 ]. This later study is important not only because it is larger than all the previous studies combined, but also because it addresses one of the major arguments offered against a potentially deleterious role of soy on fertility: that Asian diets include high amounts of phytoestrogens from soy foods without any apparent deleterious effect on fertility.…”

Overview of enterolactone biological properties and total synthesis

“…Estrogen is known to play a role in the process of spermatogenesis, and studies have shown that uncontrolled exposure to external estrogen or estrogen-like substances could have a negative impact on male fertility. [27][28][29] A correlation has been reported between high levels of phytoestrogen and a reduced sperm count. A study conducted by Chavarro et al at the Massachusetts General Hospital Fertility Center revealed that men who consume a diet rich in phytoestrogen, especially soy foods, have 35 million less sperm/mL compared to men who had little phytoestrogen in their diet.…”

“…28 Xia et al conducted a study which suggested that Chinese men, typically on a high phytoestrogen diet, have a median sperm count of 48.9 million lower than those with a lower phytoestrogen intake. 29 In light of these studies, it can be concluded that the quantity of lignan consumed can negatively affect male fertility.…”