Teenagers gorging on fast food are not only putting their long-term health at risk but also limiting their chances of having children, doctors have said.
The significant damage done to sperm quality through regular consumption of junk food has been outlined in a study by scientists at Harvard University.
Fertility doctors in the UAE backed the findings, and said pizzas, burgers and other highly processed fatty food can have a devastating impact on sperm producing Sertoli cells.
While switching to a healthier diet can increase sperm count within three months, experts warn the damage done to these life producing cells can be permanent.
“The study strongly suggests the after-effects of an unhealthy lifestyle during our younger years,” said Dr Laura Melado, at the IVI Fertility Abu Dhabi clinic.
“This time, it correlates unhealthy eating with male fertility.
“While fertility is not something that our teenagers think about just yet, the findings should nonetheless raise an alarm.”
The study found young men who mostly ate processed junk food had 25.6 million sperm per ejaculation - when a low sperm count is classified as being less than 39 million by the World Health Organisation - compared to those who reported more balanced and plant-based diets.
The report noted an increase in sperm count within three months through diet change, but found the damage to Sertoli cells - which help in the production of sperm - was irreparable.
The medical data of nearly 3,000 men with an average age of 19 were collected for the study.
Teenage participants answered a questionnaire categorising them into four diets.
Categories were mainly junk food, a prudent diet of mostly chicken, fish, vegetables and fruit, a Scandinavian diet of processed meats, whole grains, cold fish and dairy and a traditional vegetarian diet.
Sperm concentration, volume, and motility of those with largely junk food diet were considered the worst compared to other diets.
Results of hormonal tests revealed their depleted Sertoli cells.
Male infertility is determined by semen analysis to establish the number of sperm, their motility and shape.
Several other factors can lead to male infertility, such as unhealthy lifestyles, drug use or hormonal and genetic disorders.
Men over 40 are also more likely to find difficulty in conceiving.
Dr Melado said almost 40 per cent of all infertility cases are due to male-related issues, with low sperm count the number one reason for male infertility.
“We hope the results of this latest study will bring a mindset change and lead to concrete actions and wider understanding,” she said.
“For our overall health and well-being, we cannot stress enough the importance of consuming a healthy diet and engaging in active lifestyle.
“In the Middle East, several government-led programmes in this regard have already been launched, and we fully support these initiatives.”
One of the programmes is to make the calorie content of food in restaurants more available.
However, a Dubai Municipality initiative for diners to make more informed choices in restaurants has been shelved for two years. The industry has been given more time to fall in line with a new mandatory rule announced earlier this year.
In May, the environment, health and safety control sector at Dubai Municipality announced businesses with more than five outlets must comply by the ruling before December.
That deadline has been extended to 2021.
“It is not just junk food that can cause a problem, rather the total calories consumed,” said Dr Pankaj Shrivastav, director of Conceive Gynaecology and Fertility Hospital in Dubai and Sharjah.
“The obesity epidemic is causing hormonal issues in young boys and girls.”
Health authorities estimate as many as 40 per cent of young people could be either overweight or obese in the UAE, which has implications for reproduction as well as their own wellbeing.
“When boys become grossly obese they have huge numbers of fat cells that work to turn the male hormone testosterone into oestrogen,” said Dr Shrivastav.
“They will find waning libido and impact on sperm quality.
“Girls who put on weight can suffer latent polycystic ovarian syndrome where more of the male hormone androgen is produced, so it is an issue for both sexes."
Eating fast food regularly does not merely hamper the fertility of men, research has found.
A survey of 5,598 women, from Australia, New Zealand, the UK and Ireland, carried out last year, found those who ate fast food four or more times a week took nearly a month longer to get pregnant than those who never or rarely ate it.
Experts said it suggested a good diet boosted the chances of conceiving.