A lot of fertility research has focused on female factors. However, sperm quality also has an important role in conception. Danish researchers have conducted two studies on testicular function and dietary intake.
Diet Rich in Fish Linked to Improved Sperm Quality:
In one study, the scientists analyzed dietary patterns among 2,935 young men (JAMA Network Open, Feb. 21, 2020). Separately, they also assessed the men’s hormone levels, testicular health and semen quality.
They identified four different eating patterns overall: Western, prudent, open-sandwich and vegetarian-like. The Western pattern featured more pizza, French fries, red meat, processed meats, snacks, refined grains, sweets and sugar-sweetened beverages. The prudent pattern had more fish and chicken in place of meat, more vegetables and fruits rather than snacks and refined grains, and water rather than sugar-sweetened beverages. Men following the typical Danish open-sandwich pattern consumed more cold processed meats, cold fish, mayonnaise, whole grains (such as rye bread) and dairy products. In the vegetarian-like eating pattern, the men avoided meat and chicken and ate more eggs and vegetables. They drank soy milk rather than cows’ milk.
The young men reporting prudent dietary habits also exercised more. Their diets were richer in omega-3 fatty acids, presumably because of the fish they ate. In addition, their sperm counts and overall sperm quality were significantly higher than those favoring the Western-style diet. Men who followed a vegetarian-like dietary pattern also had significantly higher sperm counts than the pizza-lovers. (We don’t know why one of the dietary patterns is classified as vegetarian-like rather than simply vegetarian.)
The scientists concluded:
“Our findings support the evidence that adhering to generally healthy diet patterns is associated with better semen quality and more favorable markers of testicular function.”
Fish Oil and Higher Sperm Count:
In another study, different investigators recruited young Danish men undergoing their examinations for military service (JAMA Network Open, Jan. 17, 2020). They asked the 1,679 guys who agreed to participate in the study about supplement use. The scientists also assessed testicular health, hormone levels, semen volume and sperm quality. They found that men reporting fish oil use had better testicular health than those who did not take fish oil. No other supplements were associated with higher sperm counts and higher free testosterone. Regular fish oil users had an average sperm count of 184 million compared to 147 million for the young men (19 years old) who did not smoke, were not exposed to smoking in utero and reported themselves to be in good health but took no fish oil.
The researchers concluded (unfortunately in medicalese):
“In this large cross-sectional study, we found positive associations of self-reported use of fish oil supplements with testicular function as measured by higher semen volume, total sperm count, and testis size, lower FSH and LH levels, and a higher free testosterone to LH ratio. As we found no clear associations of intake of other supplements with measures of semen quality, we believe that confounding by indication is not likely to explain our findings.”
They recommend further research, particularly randomized controlled trials, to confirm this association.