the high protein diet does it affect fertility? According to one study published in the journal Nutrition and Health on March 7, adopting a high-protein diet could reduce the chances of having children for men. English researchers have shown that men who consumed more than 35% protein had lower testosterone levels and higher stress hormone (cortisol) levels that would
harmful to fertility.
High protein diet: less testosterone
Many men choose this type of diet in order to increase their muscle mass or lose weight. Researchers at the University of Worcester therefore examined a total of 309 patients, all healthy men aged around 27, whose diets contained varying amounts of protein. Some had a diet high in protein and low in carbohydrates while others ate more carbohydrates and less protein.
The University of Worcester has called a “moderate carbohydrate” diet a diet where carbohydrates make up less than 35% of an individual’s total energy intake and estimated thata “high carbohydrate” diet was one where carbohydrates accounted for more than 35% of total energy intake. The researchers also demanded a 20% difference between the overall carbohydrate composition of the two diets. The diets also had different durations ranging from two days to eight weeks to assess fertility risks depending on the length of the dietary restriction.
Watch out for adverse endocrine effects
As a result, the researchers found that study participants who ate a low-protein, low-carb diet had no long-term changes in their testosterone levels. high-protein, low-carb diets “strongly decreased resting total testosterone levels and after exercise”, suggesting that “people on such diets should do watch out for adverse endocrine effects“. Indeed, a large decrease in testosterone levels was observed in men who consumed more than 35% protein. The average decrease in testosterone levels in people on a high protein, low carbohydrate diet was approximately 37%.
A maximum protein consumption of 25%
“The low-carb diets may have endocrine effects, although individual studies are conflicting. This is why this work was carried out on the effects of high protein diets on testosterone and cortisol (stress hormone) in men”, specifies the study. According to Joseph Whittaker, lead author of the study, “people on a high protein diet should limit their protein intake to no more than 25%“.
Researchers therefore warn of the dangers of diets that are too high in protein on the decline in male fertility, but point out that this does not concern most people with a balanced diet. “Most people eat about 17% protein, and the high protein diets that caused a drop in testosterone were all above 35%, which is very high,” said the study’s lead author.