In July, redOrbit published an article on some of the lesser-known causes of low sperm count. One entry on the list was vegetarianism, based on a study by Linda Loma University Medical Center, which linked low sperm count with vegetarian and vegan diets.
The study was reported by major media outlets in October, 2014 – but having become aware of the unreliability of definitive conclusions, we decided to investigate further. We began by going straight to the source: the Linda Loma obstetrician, Dr. Eliza Orzylowska, who worked on the original research.
“Our study was an observational study which showed a difference in sperm concentration and total motility between lacto-ovo vegetarians and non-vegetarians with a more negative association seen in vegetarians regarding these two semen quality parameters,” Orzylowska told us.
“However, the values for lacto-ovo vegetarians were not to the infertile range according to World Health Organization semen analysis parameters. We noted an association, but the most important limitation remains that this was an observational study which does not clearly determine causality or clinical significance of the findings.”
She continued: “It is important to note that couples struggling with infertility are often willing to do more to enhance their fertility potential. Evidence-based lifestyle adjustments which positively influence their abilities to conceive are excellent tools for patients, but recommendations for diet modification require further studies and confirmation of current findings.”
No meaningful clinical recommendations
Dr. Orzylowska also added that: “Dr. Chavarro from Harvard University and the Massachusetts General Hospital Fertility Center has found similar semen analysis differences associated with soy food and isoflavone intake. There are more current ongoing studies searching for the underlying reasons for these semen quality differences. We do think there could be a causal relationship between diet and sperm quality, but cannot make meaningful clinical recommendations at this time.”
RedOrbit also spoke to Dr. Marcin Stankiewicz, Medical Director at the City Fertility clinic in Adelaide, Australia, who said that:
“There is no scientific evidence linking a vegetarian diet to a low sperm count. Some studies have suggested that substituting soy for meat may impact on human fertility. Soy is a dietary source of isoflavones, an important class of phyto-estrogens, a chemical that might impact on the reproductive system.”
“However,” he concluded, “further research is needed before any firm link can be drawn between consumption of soy and/or a vegetarian diet and low sperm count. A balanced healthy diet is an important factor when trying to conceive, and this applies to all couples, whether they follow a vegetarian or non-vegetarian diet.”
On balance, then, while discussion on the subject is not without merit, there appears to be little reason for people on vegetarian and vegan diets to assume a risk of related infertility.
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