Tuesday 31 July 2018

Consumption of nuts helps male fertility

A recent study has revealed that nut consumption improves sperm quality. This finding is consistent with the results from past studies, that examined the diet of men in relation to their fertility.


Infertility is a global problem and affects 15% of all couples of child-bearing age. In a quarter of these cases, the male is responsible for the infertility, often due to reduced sperm quality. 

A study performed at the Spanish Rovia i Virgili University [1] has revealed that the consumption of nuts can significantly improve sperm quality. The researchers do emphasise that the participants in this study were healthy, fertile males. They said that the potential benefits of eating nuts must still be investigated in men who struggle with their fertility. The results of the study were recently presented at a conference of the European Society of Human Reproduction and Embryology in Barcelona.


60 grams of nuts a day

For the study, 119 men aged between 18 and 35 years were recruited, who were then divided into two groups: one group ate 60 grams of almonds, hazelnuts or walnuts a day for fourteen weeks, in addition to their normal western diet, whilst the second group ate no nuts. 
After fourteen weeks, a significant improvement in sperm quality was evident in the first group (who ate nuts): the number of sperm cells increased, as did the vitality, the speed of movement and the shape of the sperm cells. And these are all parameters that are associated with male fertility. Furthermore, there was also a significant reduction in the level of DNA fragmentation, a benchmark that is also associated with male fertility.


Healthy diet helps conception

Does this mean that men who wish to father a child should add nuts to their diet? The researchers are cautious,  but at the same time point out that in literature more and more evidence can be found that a healthy diet, which includes eating nuts, can help conception. [2] 
They also base this on a systematic review that they themselves performed in 2017 along with the Pere i Virgili Health Research Institute. During this review they analysed in detail all observational studies into sperm quality and male fertility in relation to diet, nutrition and the consumption of nutrients. [3]
This review revealed that low sperm quality is often associated with an excess of saturated fatty acids and trans fatty acids and a lack of omega-3 fatty acids, vitamin C, E, beta carotene, selenium, zinc, cryptoxanthin and lycopene. Or: diets high in red and processed meat, soya, potatoes, full-fat dairy, cheese, alcohol, high-sugar soft drinks and sweets lead to reduced sperm quality. Whilst a diet with a lot of fish, crustaceans, shellfish, vitamin D and folic acid, grains, nuts, fruit and vegetables are beneficial in this respect. It should be noted that we recommend not eating too many grains.


Other studies with walnuts

Another study performed in 2017 involving mice shows that a walnut-enriched diet can improve sperm quality by reducing lipid peroxidation, a process that can damage the cell membranes of sperm cells. [4] These membranes are mainly made from polyunsaturated fats (PUFAs), and walnuts are richest in PUFAs (30 grams of walnuts contain around 13 grams of PUFAs of the total fat content of 18 grams). 
These findings in mice are also again supported by past studies that show that walnuts may be a key nutrient for sperm function. For example, a randomised controlled trial (RCT) involving 117 men revealed that there was a clear improvement in sperm quality in half of this group of men, who ate 75 grams of walnuts a day. [5] 



The results of these different studies show that eating a healthy diet, an important part of which is a daily portion of nuts or walnuts, can significantly improve sperm quality in men. 



[1] Abstract O-238, Wednesday 4 July 2018: Effect of nut consumption on semen quality and functionality in healthy males: a randomized controlled trial 
[3] Albert Salas-Huetos et al, Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies, Human Reproduction Update (2017). DOI: 10.1093/humupd/dmx006 [4] Lauren S. Coffua et al, Effectiveness of a walnut-enriched diet on murine sperm: involvement of reduced peroxidative damage, Heliyon (2017). DOI: 10.1016/j.heliyon.2017.e00250
[5] Robbins WA, Xun L, FitzGerald LZ, et al. Walnuts improve semen quality in men consuming a Western-style diet: randomized control dietary intervention trial. Biol Reprod. 2012;87(4):101