In 2017, scientists announced that the sperm of the Western world are struggling. Sperm counts have sharply declined in the past 40 years, and those that remain are swimming slower and sometimes have abnormal shapes. We still don’t know exactly what’s causing that dip in sperm quality, but the international nut industry is arguing that 60 grams of nuts per day will solve a myriad of sexual woes.
In June, a team of scientists from Spain published a paper in Nutrients showing that men who ate 60 grams of nuts each day reported increases in sexual desire and orgasmic function but no differences in overall sexual satisfaction. The paper is part of a bigger study on nuts and orgasms funded by the International Nut and Dried Fruit Council (INC), an industry group that includes 800 dried fruit and nut companies in 70 countries.
INC appears to have a keen interest in fertility research. In 2015, it launched a clinical trial aptly named FERTINUTS, which yielded the current study and one earlier paper proclaiming that eating nuts was key to better sperm quality.
The most recent study looks into the effect of nuts on sexual function specifically.
Nuts and Orgasms
Albert Salas-Huetos, Ph.D., is a co-author of the recent trial on nuts and sexual function who now works at the University of Utah. He believes that there’s good evidence suggesting that nuts have some holistic effect on sexual function. While he reports no individual grants from INC, one of his co-authors received grants from Pistachio Growers and another is an unpaid member of INC’s scientific advisory board.
According to Salas-Huetos, hazelnuts, almonds and walnuts contain high levels of vegetable proteins and unsaturated fatty acids as well as antioxidants and vitamins like folic acid, tocopherols, and vitamin B6. There’s some research to show that some of these elements, especially fatty acids, are linked to fertility: For instance, a mouse study published in Andrology in 2017 showed that fatty acids can positively affect sperm quality.
“Nowadays accumulating data from observational and a few randomized clinical trials suggest that this association is really clear,” he tells Inverse via email.
In the new study, Salas-Huetos and his team evaluated the effects of nuts on the sexual experiences of 83 men who were enrolled in the FERTINUTS trial. Forty-three of those men ate 60 grams of nuts per day for 14 weeks, and at the end of the trial, they reported more sexual desire and better orgasms.
But when it comes to explaining why this association exists, there are many lingering questions.
The team was particularly interested in the role of the nonessential amino acid arginine, which was present in “relatively high” amounts in the FERTINUTS nut samplers. Arginine is converted to nitric oxide (NO) once it’s in the body, which is known to dilate blood vessels, including smooth muscle around the penis. Their hope was that nuts that contain arginine (like pistachios) would set off a chain reaction leading to higher circulating levels of NO, and therefore an erection when the time comes.
But when the team investigated whether eating nuts would help raise levels of NO, they found no statistical differences between the nut group and the control group.
So, this study doesn’t really show us whether there is an biological connection between eating a package of nuts labeled “FERTINUTS” and improving sexual function, and neither have any of the earlier studies that analyzed the FERTINUTS data. But the men who participated in the trial reported improvements anyway.
Why Is the Nut Industry So Into Sperm?
Inverse reached out to the International Fruit and Dried Nut Council to clarify why they’ve set their sights on fertility but has not received comment. The idea that diet can influence fertility, however, isn’t one that only the nut industry is taking advantage of.
One of the many circulating explanations for sperm decline is that unhealthy, Western-style diets are to blame. Research presented at the 2019 Annual Meeting of the European Society of Human Reproduction and Embryology, for example, found that men who adhered to one such diet consisting of foods like pizza, chips, and red meat had average sperm counts 25.6 million lower than those who ate a “prudent diet” of vegetables or fish.
Since diet may affect sperm quality in the negative sense, there is also interest in exploring its benefits. Independent teams of researchers have set out investigate how healthy eating impacts male fertility, as has the International Nut Council. The online registration for the FERTINUTS trial refers to global sperm declines and argues that nuts can improve semen quality “because nuts have a considerable amount of several nutrients that are involved in male fertility.”
The general idea that diet may affect sperm quality — and by extension fertility — isn’t too far fetched. But whether that happens through healthy eating patterns, or can be achieved by adding a pack of nuts to the diet still remains to be seen.
INC, for its part, appears extremely eager to find out. This year, it’s offering up a 300,000-euro grant for scientific projects regarding nuts just like the FERTINUTS study, though only projects involving at least three nuts and/or dried fruits are being accepted. Their number one listed priority for 2020? Fertility.
Abstract: Lifestyle risk factors for erectile and sexual function include smoking, excessive alcohol consumption, lack of physical activity, psychological stress, and adherence to unhealthy diets. In the present study, we evaluated the effects of mixed nuts supplementation on erectile and sexual function. Eighty-three healthy male aged 18–35 with erectile function assessment were included in this FERTINUTS study sub-analysis; a 14-week randomized, controlled, parallel feeding trial. Participants were allocated to (1) the usual Western-style diet enriched with 60 g/day of a mixture of nuts (nut group; n = 43), or (2) the usual Western-style diet avoiding nuts (control group; n = 40). At baseline and the end of the intervention, participants answered 15 questions contained in the validated International Index of Erectile Function (IIEF), and peripheral levels of nitric oxide (NO) and E-selectin were measured, as surrogated markers of erectile endothelial function. Anthropometrical characteristics, and seminogram and blood biochemical parameters did not differ between intervention groups at baseline. Compared to the control group, a significant increase in the orgasmic function (p-value = 0.037) and sexual desire (p-value = 0.040) was observed during the nut intervention. No significant differences in changes between groups were shown in peripheral concentrations of NO and E-selectin. Including nuts in a regular diet significantly improved auto-reported orgasmic function and sexual desire.