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Effect of whey protein supplementation on sperm quality and fertility in male mice

https://doi.org/10.1016/j.fct.2020.111366Get rights and content

Highlights

  • Protein supplements are an increasing billion-dollar industry.

  • The effect of protein supplementation on male reproduction is poorly investigated.

  • Whey-protein supplementation did not impair sperm quality and fertility in mice.

  • DNA damage and oxidative stress in epidydimal murine sperm were not affected.

  • Testis morphology and serum testosterone were also similar between groups.

Abstract

Protein supplements are a billion-dollar industry and the intake of these supplements is increasing, especially among young men. However, little is known about whether consumption of these products affects the reproductive health. The aim of this study was to assess the effect of whey protein supplementation on the sperm quality and reproductive health of male mice. A total of 48 male NMRI mice were fed with either plain tap water or a high dose of whey protein (Whey100, BodyLab) supplemented in the drinking water for 3 months. Mice was individually housed with two female mice for five days and reproductive parameters were assessed. DNA fragmentation index (DFI) was assessed at 0 h and 4 h of in vitro incubation using a sperm DNA integrity test (SDI®-test). No significant differences were detected between the groups in the epididymal sperm count, sperm motility, DFI, oxidation-reduction potential (ORP), serum testosterone, body and seminal vesicles weights, relative testis and epididymal weights, testicular morphology, number of impregnated females, or litter size. No correlation was found between ORP and DFI. These results suggest that the highest recommended human dose of whey protein supplementation do not significantly impair the sperm quality and fertility in male mice.

Introduction

Lifestyle factors such as diet, exercise, smoking habits, and alcohol intake have been proven to affect the male reproductive health (Afeiche et al., 2014; Karmon et al., 2017). In 2018, the global protein supplement market was valued at USD 14.0 billion, and the whey-based products accounted for a 56.7% share of the overall revenue (GrandViewResearch, 2019). Despite the increasing intake of whey protein supplements on a daily basis, not only by athletes and body builders, but also by young men and recreation and lifestyle users (Vargo et al., 2014), only a few studies, have investigated the effect of protein supplementation, mainly the soy protein, on reproductive health. However, a recently published pilot study reported a potentially negative effect of protein supplements on the sperm quality in a group of 20 sub-fertile Danish men (Ketheeswaran et al., 2018). The aim of the current study was to assess the sperm quality and fertility of male mice fed with a high dose of whey protein supplement for three months.

Section snippets

Animals and experimental design

Forty-eight male and 84 female Naval Medical Research Institute (NMRI) mice aged 6–7 weeks were purchased from Taconic Biosciences Inc. (Ejby, Denmark). The male mice were housed in groups of six and randomly divided into two groups receiving either plain tap water or whey protein supplementation daily for 5 days a week, for three consecutive months. ‘Whey100’ is currently the most popular protein powder in Denmark and was consumed by the majority of sub-fertile Danish men included in the study

Weights of accessory sex organs

Body weight, seminal vesicle weight, testicular weight, and relative testicular and epididymal weights in relation to the body weight, were found to be statistically insignificant among the whey protein-supplemented group and the control group, while only the epididymal weight was significantly higher in the whey protein-supplemented group compared to that in the control group (p < 0.05).

Sperm quality, testicular morphology, and serum testosterone

No statically significant differences were found in the epididymal sperm count, percentage of sperm cells

Discussion

In this animal study investigating the effect of whey protein supplementation on the sperm quality and reproductive outcomes in male mice, no statistically significant differences were found between mice fed with whey protein supplement and the control group regarding the sperm parameters and relative weights of the accessory sex organs. Furthermore, the male fertility and the litter size were not affected by a whey protein supplementation.

The findings of the present study may be considered as

Funding

We thank the Frimodt Heineke Foundation and the A.P. Møller Foundation (grant number: 18-L-0347) for sponsoring the study.

Author contribution statement

Shathmigha Ketheeswaran (SK), Stine Gry Kristensen (SGK), Susanne Elisabeth Pors (SEP), and Peter Humaidan (PH) planned and designed the study. SK, SGK, SEP, Camilla Engel Lemser (CEL), and Lenin Arturo Zuniga Jara (LAZJ) executed the study and collected the data regarding reproductive parameters and serum samples. Jane Alrø Bøtkjær (JAB) and SK performed the testosterone assays. Preben Christensen (PC) performed the SDI®-tests. Terese Kimmie Høj (TKH) performed the histological processing and

CRediT authorship contribution statement

Shathmigha Ketheeswaran: Methodology, Formal analysis, Investigation, Writing - original draft. Susanne Elisabeth Pors: Investigation, Writing - review & editing. Lenin Arturo Zuniga Jara: Investigation, Writing - review & editing. Camilla Engel Lemser: Investigation, Writing - review & editing. Terese Kimmie Høj: Investigation, Writing - review & editing. Jane Alrø Bøtkjær: Investigation, Writing - review & editing. Preben Christensen: Investigation, Writing - review & editing. Peter Humaidan:

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors thank Ida Marie Boisen, from the Department of Growth and Reproduction, the University Hospital of Copenhagen, Denmark, for her help with the sperm retrieval protocols.

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