Taking fish oil supplements may improve sperm quality in healthy young men, a replacement analysis suggests.

Studying1,679 men taking physical examinations for compulsory military service. Their average age was 19, and 98 of them reportedly took fish oil supplements before the test. Men who took fish oil supplements for at least 60 days during the last three months had higher sperm count, a greater proportion of normal sperm cells, higher average semen volume and bigger average testicular size. They also had significantly lower FSH levels and lower LH levels, both indicators of higher testicular function.

There was also a dose-response effect for fish oil: those that took supplements on quite 60 days had a better testicular function that those that took them less often. The scientists found no effect among men who took supplements aside from fish oil, like vitamin C, vitamin D or multivitamins.

Dr. Tina Kold Jensen of the Copenhagen University Hospital found that young healthy men who took supplements had a far better sperm count.