Impact of the vegan diet on sperm quality and sperm oxidative stress values: A preliminary study

Abstract

Background: Insufficient nutrition and inappropriate diet have been related to many diseases. Although the literature confirms the hypothesis that particular nutritional factors can influence the quality of semen, until today, there are no specific dietary recommendations created for infertile males. Since the male contribution to the fertility of a couple is crucial, it is of high importance to determine the dietary factors that can affect male fertility. Aim: The aim of the present study was to evaluate differences in sperm quality parameters, sperm oxidative stress values and sperm acrosome reaction between vegan diet consumers and non-vegans. Setting and Design: Prospective study in a University Medical School. Materials and Methods: The present study was undertaken to evaluate the sperm quality parameters of vegan diet consumers (10 males who had a strictly vegetable diet with no animal products) and compare them with non-vegans (10 males with no diet restrictions). Semen quality was assessed following the World Health Organization (2010) criteria. Acrosome and DNA integrity has been evaluated using the immunofluorescence technique. Statistical Analysis: All variables were analysed by IBM SPSS version 24. Mean differences among groups were compared by Mann–Whitney U-test. Results: Obtained results showed that total sperm count (224.7 [117–369] vs. 119.7 [64.8–442.8]; P = 0.011) and the percentage of rapid progressively motile sperm were significantly higher in the vegan group compared with the non-vegan group (1 [0–7] vs. 17.5 [15–30]; P < 0.0001). Furthermore, the oxidation-reduction potential (0.4 [0.3–0.9] vs. 1.5 [0.6–2.8]; P < 0.0001) and the proportion of spermatozoon with DNA damage (14.7 [7–33.5] vs. 8.2 [3–19.5]; P = 0.05) were significantly higher in the non-vegan group in comparison to the vegan group. Conclusions: Results obtained in this study provide additional evidence about the favourable effect of a plant-based diet on sperm parameters. To confirm our preliminary findings, further studies including larger cohorts are warranted.

The impact of vegetarian diet on sperm quality, sex hormone levels and fertility: a systematic review and meta‐analysis

“…Overall, 73 articles were selected for full-text screening. Finally, 20 eligible articles 14,28,31,33,34,[37][38][39][43][44][45][46][47][48][49][50][51][52][53][54] were included for qualitative synthesis, of which 16 were appropriate for quantitative synthesis. 28,31,33,34,[37][38][39]44,45,[47][48][49][51][52][53][54] The detailed selection process is shown in Figure 1.…”

“…Studies were published between 1982 and 2021 and were conducted mainly in the United States (n = 8), 28,39,[47][48][49][51][52][53] followed by the United Kingdom (n = 5) 33,34,43,44,54 and Canada (n = 2). 14,37 Also, one study was reported from each one of the following countries (Chile, 46 Italy, 45 India, 50 Belgium 38 and Germany 31 ). Eighteen studies were designed as crosssectional and two studies as case-control.…”

“…Our systematic review comprised 3843 participants, of whom 900 adhered to a vegetarian/vegan diet and had no food restrictions. Eleven studies recruited males, of which six assessed semen/sperm quality 28,31,[43][44][45][46] (Table 2) and five studies reported sex hormonal levels 34,[37][38][39]47 (Table 3). Nine studies recruited women, of which eight reported sex hormones 14,33,48,49,[51][52][53][54] and just one article reported infertility rate differences between vegetarians and nonvegetarians 50 (Table 3).…”

“…Five studies included individuals with strict vegan diets, 31,34,[44][45][46] whereas others were conducted on vegetarian, lacto-ovo-vegetarian or both vegan and lactoovo-vegetarian diets. The types of diets were determined based on the Food Frequency Questionnaire in most of the included studies.…”

“…[28][29][30] On the contrary, some studies believed that adhering to a vegetarian diet could improve semen quality and fertility; they justified that vegetarians consume more vegetables, fruits and antioxidants, resulting in lower sperm oxidative stress and DNA damage. 31,32 Moreover, a few studies have investigated the association between vegetarianism and sex hormone levels, which revealed that adherence to a vegetarian diet could increase the level of sex-hormone-binding globulin (SHBG) and decrease the urinary levels of oestrogen in postmenopausal women, but they reported dissimilar results on the effect of a vegetarian diet on sex hormones in premenopausal population; furthermore, the possible impact of a vegetarian diet on fertility regarding sex hormones was not well established in these articles. 14,[33][34][35][36] Also, previous studies on the association between a vegetarian diet and male sex hormone profile reported discordant results; whereas some studies reported higher testosterone and SHBG levels in vegetarians, 34,37 others did not find an association.…”