Growing evidence suggests a strong link between diet and reproductive health, and a new study published in Human Reproduction adds a concerning piece to that puzzle. Researchers have found that high consumption of ultra-processed foods – those typically high in sugar, fat, and additives – is associated with reduced fertility in men and slower early embryo development in both men and women. The findings underscore the importance of dietary choices not just for overall health, but specifically for those planning a family.
The study, led by Dr. Romy Gaillard, a paediatrician and associate professor of developmental epidemiology at Erasmus University Medical Center in Rotterdam, Netherlands, analyzed data from 831 women and 651 male partners participating in the Generation R Study Next Programme, a long-term study following families from before conception into their children’s lives. This research represents one of the first comprehensive investigations into the combined impact of both parents’ diets on fertility and early embryonic development. Understanding these connections is increasingly vital, as ultra-processed foods now constitute a significant portion – up to 50-60% – of the daily diet in many high-income countries.
How Ultra-Processed Foods May Impact Fertility
Defining “ultra-processed foods” can be tricky, but generally, they are industrial formulations made mostly from substances extracted from foods – oils, fats, sugars, starch, and proteins – with little to no whole foods. They often include additives like preservatives, emulsifiers, and artificial flavors. Common examples include sugary drinks, packaged snacks, processed meats, and ready-to-eat meals. The researchers assessed participants’ diets using questionnaires administered during early pregnancy, categorizing food intake as either ultra-processed or non-ultra-processed.
The study revealed distinct patterns. In men, higher consumption of ultra-processed foods was linked to a greater risk of subfertility – defined as taking 12 months or more to conceive, or requiring assisted reproductive technology – and a longer time to achieve pregnancy. Although the exact mechanisms aren’t yet fully understood, researchers believe the impact on sperm quality may be a key factor. Sperm are particularly sensitive to dietary composition, and the nutritional deficiencies inherent in ultra-processed diets could negatively affect their development and function.
For women, the connection was more nuanced. While ultra-processed food intake wasn’t consistently linked to the time it took to turn into pregnant, it *was* associated with slightly smaller embryonic growth and reduced yolk sac size by the seventh week of pregnancy. The yolk sac is crucial for providing early nourishment to the developing embryo, and its size is an indicator of overall health. “These differences in early human development were small, but are key from a research perspective and at population level,” explained Celine Lin, the study’s first author and a PhD student at Erasmus University Medical Center. “We showed for the first time that UPF consumption is not only important for the health of the mother, but may also be related to development of the offspring.”
Early Development and Long-Term Health
The implications of these findings extend beyond immediate fertility concerns. Previous research has established a link between slower embryonic growth in the first trimester and an increased risk of adverse birth outcomes, including premature birth, low birth weight, and an elevated risk of cardiovascular problems later in life. Studies have also shown that impaired yolk sac development can increase the risk of miscarriage and premature birth.
Dr. Gaillard emphasized the need for a broader perspective on fertility and early pregnancy. “Our research shows that we should move away from the idea that only the health and lifestyle of mothers-to-be is important for pregnancy and offspring outcomes, and recognize that the health and lifestyle of both the mother- and father-to-be play an important role,” she said. “Our results highlight the need to pay more attention to male health in the preconception period, which has traditionally been overlooked.”
Limitations and Future Research
It’s important to note that this study is observational, meaning it can demonstrate associations but cannot definitively prove cause and effect. The researchers acknowledge this limitation, stating that further research is needed to confirm their findings in diverse populations and to unravel the underlying biological mechanisms. Questions remain about whether the effects are driven by the lack of nutrients in ultra-processed foods, exposure to additives, or even the presence of microplastics – a growing concern in food safety.
Future studies will also investigate whether these early developmental differences have lasting consequences for the growth and development of children. Researchers are also keen to explore the potential benefits of dietary interventions aimed at reducing ultra-processed food consumption before and during pregnancy.
For now, the message is clear: prioritizing a diet rich in whole, unprocessed foods – fruits, vegetables, lean proteins, and whole grains – appears to be beneficial for both prospective parents and the health of their future children. This isn’t about restrictive dieting, but rather about making informed choices to support reproductive health and lay the foundation for a healthy start to life.
Disclaimer: This article provides information for general knowledge and informational purposes only, and does not constitute medical advice. We see essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
The European Society of Human Reproduction and Embryology (ESHRE) continues to support research into the factors influencing reproductive health. Updates on this and related research will be available on their website: www.eshre.eu. We encourage readers to share their thoughts and experiences in the comments below.
