Soy Linked to Low Sperm Count

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<http://www.livescience.com/health/617728.html>

> (HealthDay News) -- Eating half a serving of soy food a day lowers

> sperm concentrations and may play a role in male infertility,

> particularly in obese men, Harvard University researchers report.

>

> The reason for this relationship between soy and sperm count isn't

> clear. However, researchers speculate that soy increases estrogen

> activity, which may have a negative affect on sperm production and

> also interfere with other hormonal signals.

>

> " There have been a lot of interest in estrogen and isoflavones in

> particular and a potential relationship to fertility and other

> reproductive disorders, " said lead researcher Dr. Chavarro, a

> research fellow in the department of nutrition at the Harvard School

> of Public Health.

>

> Research in animals has shown that isoflavones and estrogen can have

> a potentially negative affect on reproduction, including decreased

> fertility, Chavarro said. However, there is very little evidence of

> how these findings apply to humans, he said.

>

> The new research, he added, lends support to how results of animal

> studies apply to humans. But Chavarro considers the findings

> preliminary and inconclusive. " It's way too early to say stop eating

> soy foods, " he said. " It's not time to worry about whether you're

> eating too much soy. There's not enough information to conclusively

> say that. "

>

> His report was published in the July 24 online edition of the

> journal Human Reproduction.

>

> For the study, Chavarro and colleagues collected data on 99 men who

> attended a fertility clinic for evaluation. The men were asked about

> how much of 15 soy-based foods they ate in the past three months.

>

> The foods men were asked about included tofu, tempeh, tofu or soy

> sausages, bacon, burgers, soy milk, cheese, yogurt, ice cream and

> other soy products like roasted nuts and energy bars.

>

> Because different foods have different levels of isoflavones, half a

> serving of soy is equal to about one cup of soy milk or one serving

> of tofu or soy burgers every other day, Chavarro noted.

>

> Chavarro's team found that men who ate the most soy had 41 million

> fewer sperm per milliliter of semen compared with men who did not

> eat soy foods. Normal sperm counts range between 80 million and 120

> million per milliliter, according to a press release from the

> journal, a monthly publication of the European Society for Human

> Reproduction and Embryology.

>

> ...

Of course it's " not time to worry about whether you're eating too much

soy. " Naturally.