Eating walnuts may boost sperm quality

Healthy young men with a Western-style diet may be able to boost their sperm quality by eating a small packet of walnuts a day.

These are the findings of a new study that shows healthy American men in their 20s and 30s who ate a 75g (2.5 ozs) packet of walnuts a day were able to increase the vitality, motility and structure of their sperm compared to counterparts who did not eat walnuts.

A report on the study appeared online on 15 August in the Biology of Reproduction journal's papers-in-press section.

75 g is about 2.5 ozs, equivalent to one of those small snack-style packs you can get in the supermarket.cWalnuts are rich in polyunsaturated fatty acids (PUFAs), which play an important role in maturing sperm and preserving the integrity of the membrane around the cell which in turn affects its ability to fertilize an egg.

In the Western-style diet, PUFAs are usually found in fish, fish oil supplements, flax seed and walnuts. Walnuts also offer an important source of linolenic acid (ALA), a natural plant source of omega-3.

For their study, which was partially funded by the California Walnut Commission, they enrolled 117 healthy men aged 21 to 35 who followed a Western-style diet. The participants were randomly assigned to one of two groups: 58 were asked to avoid eating tree nuts, and 59 were asked to eat 75 g of walnuts a day.

The researchers assessed semen quality using the traditional measures of male fertility. These include sperm concentration, vitality (living versus dead sperm), motility (how well they travel towards an egg), morphology (shape and structure), and chromosome abnormalities.

The results found at the end of the 12 weeks, neither group showed significant changes in body weight, body mass, or physical activity levels (these factors can also affect sperm quality).

However, the men in the walnut group had higher levels of omega-6 and omega-3 (ALA) fatty acids in their blood at the end of the study period than they did at the start.

The men in the walnut group also experienced improvements in sperm quality over the 12 weeks of eating walnuts, there were significant increases in measures of vitality, motility, and morphology. Their sperm also showed fewer chromosome abnormalities at the end of the 12 weeks than it did at the start of the study.

The control group, however, showed no such changes.

For more information on natural ways to improve sperm quality, see our Lifestyle & Fertility pages.