Monday, October 20, 2014
Vegetarians and vegans may be harming their chance of having children after a study found that men who do not eat meat have significantly reduced sperm counts
Although a diet that is rich in fruit and vegetables can protect against many illnesses and can prolong life, it appears that it may also harm fertility. Researchers at Loma Linda University Medical School, in southern California, embarked on a four-year project to find out how diets affect sperm. The region has a high population of Seventh-Day Adventist Christians who believe that meat is impure and so are strict vegetarians. Seventh-day Adventists live an average of 10 years longer than the American life expectancy of about 79 years and the researchers wanted to find out if their astonishing longevity might be linked to sperm quality. However they found the opposite. Vegetarians and vegans had significantly lower sperm counts compared with meat eaters, 50 million sperm per ml compared with 70 million per ml. They also had lower average sperm motility – the number of sperm which are active. Only one third of sperm were active for vegetarians and vegans compared with nearly 60% for meat eaters. The team believes that vitamin deficiencies may be to blame but also believe that replacing meat with soy could be responsible. “We found that diet does significantly affect sperm quality. Vegetarian and vegan diets were associated with much lower sperm counts than omnivorous diets,” said Dr Eliza Orzylowska an obstetrician at Loma Linda University Medical Centre in California. “Although these people are not infertile, in is likely to play a factor in conception, particularly for couples who are trying to conceive naturally. The old fashioned way.” One factor could be diets rich in soy, the researchers hypothesis. Soy contains phyto-estrogens which have similar properties to the female hormone estrogen. “The theory that we have come up with is that vegetarians are replacing meat with soy, which contains phytoestrogens and could be affecting fertility,” added Dr Orzylowska. “For children who have grown up with those kind of diets, it may have impacted on sperm quality from puberty. 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.” The researchers also think that vegetarians and vegans may be deficient in vitamin b12. The study compared 443 meat eaters with 26 vegetarians and five vegans. Separate research from Harvard University also found that a diet high in fruit and vegetables may impact fertility because men are consuming high quantities of pesticides.