Eating Soy When Trying to ConceiveKatlyn Joy | 6, October 2014
Perhaps no other food item has been as controversial as soy in the last decade or two. It's been linked to benefits such as boosting female fertility, protecting from breast and prostate cancer, hampering cardiac disease and relieving menopausal symptoms and preventing osteoporosis. On the negative side, it's been connected to reproductive issues in females, fertility problems in males and affecting the thyroid gland and function.
The consumption of soy has been on a significant climb since the 1990s. In 1992, sales were at the 0 million level; by 2008 the number was at billion. Many school lunch programs add soy to their hamburgers to boost health effects and the Food and Drug Administration promotes it as a healthy way to fight reduce heart disease risks.
What are the Concerns over Soy?
In 2008, a study published in the journal Human Reproduction, concluded that higher intake of soy and soy isoflavones resulted in lower sperm concentration. The results were more pronounced in overweight and obese men.
However, in 2011, a University of Guelph, Ontario, Canada, study found the opposite to hold true in their research. Their findings were subsequently published in the journal Fertility and Sterility.
Alison Duncan, the study author and a professor of human health and nutritional sciences takes issue with the popularly held concept that soy increases estrogen and therefore interferes with male fertility.
"But we found that consuming soy on a regular basis had no effect on semen quality, which is a direct measure of fertility."
A 2014 study published in the journal Alternative Therapies in Health and Medicine, did a review of literature concerning soy, and the authors stated, "The evidence on male fertility and reproductive hormones was conflicting; some studies demonstrated a deleterious impact caused by soy consumption and others showed no effect."
Regarding female fertility, a study published in 2012 in Biology of Reproduction, dealt with the issues of soy exposure in the womb or via baby formula affecting a woman's later fertility. The study only researched the effects within mice, and found that exposure caused infertility in the rodents.
In an abstract of the article, it was stated, "The authors present the view that limiting such exposures, including minimizing use of soy-based baby formula, is a step toward maintaining female reproductive health."
Retha Newbold, a developmental biologist at the National Institute of Environmental Health Sciences, says that more definitive answers are needed from human studies, but, "We know that too much genistein is not a good thing for a developing mouse; it may not be a good thing for a developing child."
Genistein is a main isoflavone in soy and disrupts hormones.
For those who say the rat results are a far cry from human ones, developmental biologist Heather Patisaul says, "Our reproductive system and the rat reproductive system aren't that different. The same hormones are involved."
Patisaul is employed by the North Carolina State University, and said further, "Brain development, which begins in the womb and continues through puberty, also may be altered by estrogen in soy."
While only one human study looking at soy's long lasting results have been conducted, it's results revealed women who were fed soy formula as babies had slightly longer periods and more cramping as adults.
A study out of Taiwan published this year found that mice fed genistein had reduced fertility and abnormal embryo development in females.
While the negative fertility effects in adults are likely reversed when a diet high in soy is changed, the effects on the reproductive tracts of infants could be permanent.
The Final Word
In 2008, the American Association of Pediatrics reviewed literature and determined there was no credible evidence that soy harms infant development, reproduction or endocrine functions.
However, other scientists are warning that until enough research has been completed and a conclusive answer is found, limiting soy may be the most sensible plan of action.
Perhaps, a diet moderate in soy consumption for adults, and the avoidance of soy formula unless medically indicated would be a reasonable suggestion.
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