Ultra-processed foods linked to decline in male fertility, metabolic health

A three-week trial revealed that eating ultra-processed foods changes hormone levels and reduces sperm motility, affecting both reproductive and metabolic health in men

A new study has found that regularly eating ultra-processed foods (UPFs) such as packaged snacks, ready-to-eat meals, soft drinks, and processed meats can disrupt sex hormones, reduce sperm motility, and harm overall metabolic health.

 

Published in the journal Cell Metabolism, the study titled 'Effect of ultra-processed food consumption on male reproductive and metabolic health' provides strong evidence that it’s not just the calories but the highly processed nature of these foods that makes them damaging to human health.

 

Study overview

 

Researchers from the University of Copenhagen and international collaborators conducted a randomised controlled trial with 43 healthy men aged 20-35. Participants followed two diets:

 

• Diet with 77 per cent of calories from ultra-processed foods
• Diet with 66 per cent calories from unprocessed, fresh food

 

Each diet lasted for three weeks and was calorie-matched to rule out excess calorie intake as the only cause of health changes.

 

Key findings

 

The results revealed worrying impacts of ultra-processed diets:

 

• Hormonal disruption: Levels of follicle-stimulating hormone (FSH), vital for sperm production, dropped in participants consuming UPFs, with testosterone also showing a downward trend.
• Decline in sperm quality: Sperm motility, a marker of fertility, decreased after the processed diet.
• Weight and fat gain: Participants gained up to 1.4 kg, mainly in fat mass, despite controlled calorie intake.
• Cholesterol and blood pressure changes: Low-density lipoprotein (LDL) or bad cholesterol rose, and diastolic blood pressure increased in some cases.

 

Moreover, it was noted that eating more ultra-processed food lowered levels of lithium (Li) in blood and semen. As lithium is important for mood regulation, this drop could potentially affect mental health.

 

Processed food and fertility decline

 

Sperm counts worldwide have already fallen by around 60 per cent since the 1970s, and scientists suggest the rise of processed food could be a contributing factor. The study highlights that even when calorie intake was the same, ultra-processed diets harmed reproductive and metabolic health, showing that the way food is made matters as much as the elements in it.

 

Health experts’ advice

 

Experts recommend limiting intake of UPFs and instead focusing on whole, nutrient-dense foods such as:

 

• Fresh fruits and vegetables
• Whole grains
• Nuts and seeds
• Home-cooked meals with minimal additives

 

“Moving dietary patterns away from UPF and toward less-processed alternatives may promote cardiometabolic and mental health, along with amelioration of male reproductive fitness,” the study concluded.

 

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