Soy isoflavone intake and the likelihood of ever becoming a mother: the Adventist Health Study-2

Abstract

ObjectivesAs little is known about the possible relationship between the intake of phytoestrogens and female fertility, we investigated the relationship between soy isoflavone intake and the risk of nulliparity and nulligravidity.MethodsA cross-sectional study of 11,688 North American Adventist women aged 30–50 years old with data regarding childbearing. These women were, as a group, characterized by a high proportion (54%) of vegetarians and a healthy lifestyle with a very low prevalence of smoking and alcohol use.ResultsThe mean isoflavone intake (17.9 mg per day) was very high compared to other Western populations. Only 6% of the women indicated no intake of isoflavones. We found, after adjustment for age, marital status, and educational level, an inverse relationship (P=0.05) between isoflavone intake and the likelihood of ever having become a mother. In women with high (≥40 mg/day) isoflavone intake (12% of this group of women), the adjusted lifetime probability of giving birth to a live child was reduced by approximately 3% (95% CI: 0, 7) compared to women with low (<10 mg/day) intake. No relationships were found between the isoflavone intake and parity or age at first delivery in parous women. A similar inverse relationship (P=0.03) was found between the isoflavone intake and the risk of nulligravidity with a 13% (95% CI: 2, 26) higher risk of never have been pregnant in women with high (≥40 mg/day) isoflavone intake. These relationships were found mainly in women who reported problems becoming pregnant.ConclusionThe findings suggest that a high dietary isoflavone intake may have significant impact on fertility.

Diet and female fertility: doctor, what should I eat?

“…From the available data, no such association between soy isoflavones and age at menopause has been observed (148)(149)(150)(151). Regarding fecundity of populations with no history of infertility, women with the highest isoflavone intake participating in the retrospective Adventist Health Study were more likely to be childless, whereas no relation between soy intake and fecundity was noted in a prospective cohort of couples attempting pregnancy (152,153). In women seeking fertility treatments, however, soy isoflavone supplements were associated with improvement in reproductive outcomes: increased live births after clomiphene administration (154) or higher endometrial thickness and ongoing pregnancy rates after intrauterine insemination (155) and in vitro fertilization (156).…”

The Effects and Mechanisms of Cyanidin-3-Glucoside and Its Phenolic Metabolites in Maintaining Intestinal Integrity

“…C3G&C3G-Ms potentially ameliorate micro-ecological dysbiosis by inhibiting gram-negative bacteria. But it is worth noting that a few studies have demonstrated that the over-consumption of polyphenols had significant negative effects on reproduction and pregnancy [72][73][74]. Although it is inexplicit whether there is a correlation with the changes of gut microbiota composition, the negative effects of polyphenols-mediated modulation of gut microbiota should be focused on.…”

Placebo in the guise of evidence-based medications

“…It was reported on abnormal uterine bleedings in women consuming soy products 14 , subtle gender-related behavior changes in girls 41 and gynecomastia in a man 42 . A cross-sectional study of 11,688 women showed that high intake of isoflavones was related to an increased risk of never becoming pregnant and remaining childless 43 . Hormonal effects of PE may lead to fertility problems possibly due to the influence on menstrual cycle, oocyte quality and endometrial receptivity 39 .…”