Young, fit men whose diets are made up of pizza, burgers, chips and other processed staples have drastically lower sperm counts than those who eat fresher foods, a study suggests.
The groundbreaking investigation has established that teenagers who favour high-fat and processed foods like pizzas, chips and snacks are killing off sperm-producing cells that can never be replaced. It showed that a diet dominated by fish, chicken, vegetables and fruit is best is for protecting those cells and ensuring healthy levels of sperm.
Despite being at their reproductive peak in some cases, some of the men already had clinically low sperm counts, below the 39 million sperm level, which means they might struggle to conceive naturally.
Author Dr Jorge Chavarro, of Harvard University, said: “You would be surprised to see how sensitive young men are to things that might affect sperm count, a perceived measure of masculinity.”
The study used sperm samples from around 3,000 men, with an average age of 19, undergoing a routine medical exam before joining the Danish armed forces for national service.
Men’s diets have worsened over the past few decades, coinciding with a fall in the average sperm count of almost 60 per cent, which some experts have warned could lead to the extinction of the human race.
The study is the largest of its kind to examine the impacts of diet in a group of young men who wouldn’t otherwise have any cause to check their fertility. While it hasn’t yet been published in a peer-reviewed journal, Professor Pacey said the early implications were “powerful”.
“Most men think they’re invincible until their first big health event occurs, which is often … infertility,” said ESHRE president Roy Farquharson, from Liverpool Women’s Hospital.
Sperm have a lifespan of around three months and changing diets could allow sperm production to recover.
However the study also found that men on the Western diet had lower levels of a chemical called inhibin-B which could indicate damage to sperm-producing sertoli cells, which could indicate the effects of a Western diet might be more permanent.