A recent study examined the popular view about men who are vegans and vegetarians, and came to the conclusion that the general public views meat eaters as “more masculine”. Many men also report feeling more manly when eating meat. When it comes to actual evidence, many studies (here, here, here, and here) have also shown that men who switch from meat-based to plant-based diets/foods do indeed see a drop in their serum T-levels. And several other studies have associated vegan men with having lower testosterone levels than meat-eaters have. The general consensus of the research, suggests that plant-based diets lead to lower testosterone levels and higher SHBG relative to omnivores.
The general belief is that vegetarians are usually healthier. However, studies conducted in the U.S. are showing some detrimental side-effects to the sperm of male vegetarians.
In an experiment done by researchers at Loma Linda University, 443 meat-eaters and 31 vegetarians and vegans were monitored between 2009 and 2013. They initially assumed vegetarians’ sperm would be healthy, but here’s what they found, according to lead study author Eliza Orzylowska:
“We found that diet does significantly affect sperm quality. Vegetarian and vegan diets were associated with much lower sperm counts than omnivorous diets. Although these people are not infertile, it is likely to play a factor in conception, particularly for couples who are trying to conceive naturally, the old-fashioned way.”
They also found that vegetarians had 30 percent lower concentrations of sperm (50 million per milliliter versus 70 million) and that their sperm was also weaker in terms of movement. For vegetarians, only 30 percent of their sperm were active, as compared to 60 percent of their meat-eating counterparts.
One of the theories they came up with blamed vegetarians’ high consumption of soy. In a study done three years ago, soy was discovered to shrink sperm count due to its high content of phyto-estrogen, which is similar to a female hormone that blocks sperm production.
“For children who have grown up with those kind of diets, it may have impacted on sperm quality from puberty,” said Orzylowska.
“It’s hard to tell people not to be vegetarians if they are trying to conceive, but I would caution against using soy, at least for 74 days beforehand, which is the time it takes for sperm to be replaced.“
Another explanation was the shortage of vitamin B12 in a vegetarian/vegan diet. B12 helps break down estrogen, which helps maintain a high sperm count. This vitamin is found mainly in beef and fish.
Lastly, in an independent study done at Harvard and published by the American Society for Reproductive medicine, they found that pesticides could be a factor in decreased fertility for men.
In this study, scientists studied the sperm of 155 men at the Massachusetts General Hospital between 2007 and 2012 and measured how much fruit they consumed. They found that men who consumed mostly fruit and vegetables with high pesticide residue had a 70 percent smaller active sperm count and 64 percent smaller count of normally-shaped sperm compared to men who ate fruits and vegetables least tainted with pesticides. SOURCE