High dietary intake of saturated fat is associated with reduced semen quality.
A study shows the connection exists.
A significant percentage of the saturated fat intake was derived from dairy products.
Residues of industrial chemicals may bioaccumulate up the food chain into cow fat.
Some of these lipophilic (fat-loving) chemicals has hormone-disrupting abilities.
The EPA performed a national survey of persistent, bioaccumulative,
and toxic pollutants in the U.S. milk supply.
Milk fat is likely to be among the highest dietary sources of exposure to this pollution, They tested milk from all over the country and found a witches brew of chemicals. They estimate that dairy products alone contribute about 30% to 50% of our dioxin exposure. And like dioxin, other toxic pollutant tend to be widely dispersed in the environment, bioaccumulated through the food chain and ultimately result in low-level contamination in most animal fats.
This may explain higher pollutant concentrations in fish eaters. Xenoestrogens like PCBs are associated with the fats of fish or animal flesh and cannot be fully removed by washing or cooking, so can accumulate in our fat too.
Xenoestrogens are chemicals with demasculinizing or feminizing effects. In a non-polluted world animal fats have actual estrogen, not xenoestrogen, but estrogen-estrogens, which are unavoidable constituents in non-vegetarian nutrition.
All foodstuff of animal origin contains oestradiol, which is at least 10,000-fold more potent than most xenoestrogens.
Also natural sex steroids have dietary exposure from meat, dairy products, and eggs. These hormones in these animals are identical to humans. Cow estrogen works just like human estrogen. Estrogens are also contained in meat and eggs, but the major sources are milk and dairy products. By drinking a glass of milk, a child's intake of estradiol is 4000 times the intake of xenoestrogens, in terms of hormone activity.
Modern genetically improved dairy cows can lactate throughout their pregnancy. This causes estrogen levels to jump as much as 30-fold.
Cheese intake has been associated with lower sperm concentration. Dairy food intake has also been associated with abnormal sperm shape and movement. Thus dairy intake implicates direct testicular damage besides the suppression of sperm production due to the estrogen.
While milk products supply most of our ingested female sex steroids, eggs are a considerable source as well, contributing as much as meat or fish, approximately. This is expected as eggs are produced directly in the hens’ ovaries.
Meat comes hormone enriched. In the U.S. anabolic sex steroids may be administered to animals for growth promotion, a practice banned in Europe 25 years ago. This study in New York found a progressively lower sperm count associated with processed meat consumption, but similar studies in Europe after the ban found the same thing. So it may not be the implanted hormones, but rather a consequence of other things in meat such as the saturated fat, perhaps through cholesterol. We’ve known for decades that men with high cholesterol levels show abnormalities in their spermiograms, decreased sperm concentration, about a third of the normal sperm movement, and half the normal sperm shape. 25 years later we’re finding the same thing. Cholesterol is bad for sperm. In the largest study to date, higher levels of cholesterol in our blood is associated with significantly lower percentage of normal sperm. Cholesterol was also associated with reductions in semen volume and live sperm count. These results highlight the role of fats in the blood in male fertility, given the rising prevalence of obesity and cholesterol problems.
The statin drugs did not seem to help. A healthier diet associates with healthier sperm counts and cholesterol levels.