Ultra-processed foods link

Ultra-processed foods are industrial products like packaged snacks, sugary drinks and ready meals, and a new March 24 study linked higher intake to lower male fertility and slower early embryo growth. (academic.oup.com) The study, published in *Human Reproduction*, followed 831 women and 651 male partners in the Netherlands through the Generation R Study Next Programme between 2017 and 2021. Researchers measured diet with a food-frequency questionnaire around 12 weeks into pregnancy and classified foods with the NOVA processing system. (academic.oup.com) To track fertility, the team used time to pregnancy, meaning how long it took a couple to conceive, and counted subfertility as 12 months or more or the use of assisted reproductive technology. To track very early development, they measured crown-rump length, a standard embryo size marker, and yolk sac volume on transvaginal ultrasounds at 7, 9 and 11 weeks. (academic.oup.com) The clearest fertility signal showed up in men. For each standard-deviation increase in paternal ultra-processed food intake, fecundability fell, with a fecundability ratio of 0.90, and the odds of subfertility rose, with an odds ratio of 1.36 after adjustment for other factors. (academic.oup.com) The clearest embryo signal showed up in women. Higher maternal ultra-processed food intake was tied to smaller embryos at 7 weeks, with crown-rump length lower by 0.13 standard deviation score, and smaller yolk sacs, lower by 0.14 standard deviation score; those links weakened by 9 and 11 weeks. (academic.oup.com) The yolk sac is the embryo’s first nutrient supply, like a temporary pantry before the placenta takes over. The authors said smaller yolk sacs and slower early growth could point to changes during a narrow window when organs and the placenta are just starting to form. (focusonreproduction.eu) The study did not find the same pattern for every outcome in both parents. Maternal ultra-processed food intake was not associated with fertility outcomes, and paternal intake was not associated with first-trimester embryo development after adjustment. (academic.oup.com) Ultra-processed foods are defined in the NOVA system by the extent and purpose of industrial processing, not just by calories or fat. The category includes products made mostly from extracted ingredients and additives and is widely used in nutrition research, though some scientists argue the definition can be inconsistent at the edges. (www.congress.gov) (nature.com) That debate matters because this was an observational study, not a randomized trial. The paper adjusted for socio-demographic and lifestyle factors, but it relied on self-reported diet and cannot prove that ultra-processed foods directly caused the fertility or embryo changes. (academic.oup.com) The paper adds reproduction to a longer list of health questions around ultra-processed diets. A 2024 *BMJ* umbrella review found diets higher in ultra-processed foods were associated with multiple adverse health outcomes, while the United States Food and Drug Administration said in 2025 it was partnering with the National Institutes of Health to study how these foods may affect health. (bmj.com) (fda.gov) For couples trying to conceive, the new paper shifts some attention to the months before pregnancy and to both parents’ diets, not only the mother’s. The authors said the results support cutting back on ultra-processed foods around conception while larger studies test whether the link holds up. (focusonreproduction.eu)