A randomized crossover nutrition trial found that consumption of ultra-processed food increased weight, altered lipid measures, and affected reproductive and metabolic hormones in healthy men, regardless of calorie intake.
The study enrolled 43 men (aged 20 to 35 years) who completed two 3-week diet periods separated by a 12-week washout. Diets were designed using the NOVA classification: the ultra-processed food (UPF) diet provided 77% of calories from highly processed foods, while the unprocessed diet delivered 66% from minimally processed foods.
Men consuming the UPF diet gained approximately 1.3 to 1.4 kg and nearly 1 kg of fat mass across both calorie groups, while lean mass remained unchanged. Total cholesterol and the LDL to HDL ratio increased in the adequate-calorie group, whereas diastolic blood pressure rose in the excess-calorie group. C-peptide levels also increased under adequate-calorie UPF intake.
Hormonal changes included lower follicle-stimulating hormone in the excess-calorie group and a downward trend in testosterone in the adequate-calorie group. Growth differentiation factor-15 a metabolic regulator, also decreased with excess-calorie UPF consumption. Sperm motility trended lower after UPF intake, though concentration was unchanged.
Environmental markers shifted with diet. The UPF regimen was associated with higher serum levels of a phthalate metabolite (cxMINP) and lower levels of PFOS and PFHpA. Lithium and mercury concentrations were reduced compared with the unprocessed diet. Interleukin-4 increased following the unprocessed diet in the adequate-calorie group, while C-reactive protein and oxidative stress markers remained unchanged.
“Despite the simultaneous increase in UPF consumption and decline in global semen quality, it is not clear whether UPF consumption plays a direct role in the deterioration of broader fertility trends," said Jessica M. Preston, PhD, lead author of the study and researcher at the University of Copenhagen, and colleagues.
The study had several limitations. The primary endpoint, sperm DNA methylation, was not reported in this analysis. The outcomes described were exploratory secondary measures, and although statistical corrections were applied, the findings should be interpreted with caution. The study population consisted of healthy young men, limiting generalizability to other populations. The intervention periods were short and may not reflect long-term outcomes.
Full disclosures can be found in the study.
Source: Cell Metabolism
