Meta-analysis confirms benefits of nuts for male fertility
Nutritionists and doctors advise men to eat nuts to improve fertility. The benefits of the product for men's health are also supported by scientific evidence. A systematic review and analysis of research on the topic, conducted in Australia, confirmed the beneficial effect of nuts on the reproductive abilities of the stronger half of mankind.
In the work, which experts from Monash University called the first of its kind, scientists reviewed previous studies involving a total of 646 men. Two of them were observational, that is, based on observational data, and the other two were randomized controlled trials. The researchers did not combine their results in the meta-analysis because of differences in the design of the observational studies.
The two randomized trials included 223 healthy men aged 18-35 years who followed a typical Western style of eating.
In one study, men ate 75 grams of peeled walnuts daily for 12 weeks. In the other, the experimental group was given 60 grams (about two handfuls) of a mixture of 30 grams of walnuts, 15 grams of almonds, and 15 grams of hazelnuts for 14 weeks. In the control groups in both studies, people continued to eat as usual without adding nuts to their diet.
The results of the experiments showed that eating at least 60 grams of nuts daily increased sperm motility, viability and morphology compared to the control group participants. However, the researchers found no effect on sperm concentration. In both cases, the statistical analysis was adjusted for various factors, including the physical activity of the participants.
Commenting on the data, Dr. Barbara Cardoso (Barbara Cardoso), a specialist in nutrition and dietetics from Monash University, drew attention to the fact that the subjects continued to eat in their usual style, which may not always have been healthy.
Thus, adding nuts to the diet can provide benefits even without other dietary changes. These conclusions are presented in the journal Advances in Nutrition.
Experts attribute the beneficial effect of nuts on male reproductive health to the high content of omega-3-polyunsaturated fats, dietary fiber, vitamins, minerals and polyphenols in these products.
Study co-author Nicole Kellow also dispelled a common concern about the risk of gaining weight from nuts.
"Many people think nuts make you fat, but studies show that people who eat one or two handfuls of nuts every day are actually more likely to be slimmer than those who don't include them in their diet," she said.
However, the researchers cautioned that raw or roasted nuts are good for your health. Salted and sweetened nuts should be avoided, as they can contribute to hypertension and insulin resistance.
In the future, scientists plan to continue the work and within its framework to consider the effect of nuts not only on male, but also on female fertility, since there have been no randomized clinical trials on this subject.
Note that in two observational studies, no correlation between nut consumption and male sperm quality could be found. However, in such scientific papers, the consumption of certain foods is often recorded from the words of their participants, without controlled measurements of weight, as in the other two studies on which the authors of the meta-analysis based their conclusion. In this sense, their decision to focus on randomized controlled experiments may be justified.