The relationship between plant and animal based protein with semen parameters: A cross-sectional study in infertile...

Infertility is a global challenge, affecting 15% of non-contracepting couples that have intercourse. Recent studies have shown that diet can directly affect sperm quality. Protein is one of the most important components of an adequate diet that can regulate metabolic profile and send signals to the reproductive axis. This study aimed to determine the relationship between plant and animal protein intake and infertility in Iranian men.

In this cross-sectional study, 270 infertile men aged 18-55 years were selected from Isfahan Infertility clinic in 2018. Semen assessment was performed according to the fifth edition of the WHO laboratory manual and a 168-item questionnaire was used to determine the amount of dietary intakes of participants. Statistical analyses were carried out using SPSS for Windows software (version 20.0), SPSS Inc, and Chicago IL. P-value < 0.05 was considered statistically significant.

There was significant association between concentration and plant protein tertiles in the crude model (OR = 0.38; 95% CI: 0.19, 0.75; P = 0.004), which became significant in the both adjusted model and participants in highest tertile had a lower risk (OR = 0.36; 95% CI: 0.18, 0.72; P = 0.003 and OR = 0.31; 95% CI: 0.14, 0.65; P = 0.002). Also, there was a significant association between sperm concentration and animal protein in the crude model, and participants in the highest tertile had a higher risk (OR = 2.32; 95% CI: 1.13, 4.76; P = 0.02). Participants in highest animal protein tertile had a higher risk (OR = 2.38; 95% CI: 1.16, 4.91; P = 0.02 and OR = 2.42; 95% CI: 1.13, 5.19; P = 0.02) in adjusted model. Furthermore, there was a significant association between morphology and animal protein in the crude model, and participants in the highest tertile had a higher risk (OR = 3.68; 95% CI: 0.97, 13.91; P = 0.04).

In this cross-sectional study, the relationship between plant and animal protein with semen parameters was evaluated. Although this study demonstrated the relationship between plant and animal based protein with semen parameters, more researches need to be done in this area.