New Delhi, March 24 A new study suggests that consuming large amounts of ultra-processed foods may be linked to reduced fertility in men, slower growth in early embryos, and smaller yolk sacs – which are essential for early embryonic development.
"Even though ultra-processed foods (UPFs) are so common in our diets, very little is known about their potential relationship with fertility outcomes and early human development," said lead researcher Dr. Romy Gaillard, a pediatrician and associate professor of developmental epidemiology at Erasmus University Medical Center, Rotterdam, The Netherlands.
Researchers said that until now, no study has investigated the combined impact of both parents' ultra-processed food (UPF) consumption on the length of time it takes to conceive and early embryonic development.
The study, published in the journal Human Reproduction, looked at 831 women and 651 male partners enrolled in a population-based, prospective study that has been following parents from before conception and into their offspring's childhood – the Generation R Study Next Programme.
The couples were included in the study during the pre-conception period or during pregnancy between 2017 and 2021. Information on the parents' diet and time to pregnancy were measured using questionnaires.
Fecundability – the chances of conceiving within a month – and subfertility, which is the time to pregnancy of 12 months or more or the use of assisted reproductive technology, were also measured.
The distance between the embryo's head and its buttocks – an indication of its size and development – and the volume of the yolk sac were measured by transvaginal ultrasound at seven, nine, and 11 weeks of gestation.
Typically, consumption of UPFs made up 22 per cent and 25 per cent of the women's and men's total food intake, respectively, the study found.
"We observed that UPF consumption in women was not consistently related to the risk of subfertility and time to pregnancy, but was associated with slightly smaller embryonic growth and yolk sac size by the seventh week of pregnancy," said first author Celine Lin, a PhD student at Erasmus University Medical Center.
Lin added that the differences in early human development were small, but important from a research perspective and at a population level, as the team showed for the first time that UPF consumption is not only important for the mother's health, but may also be related to the development of the offspring.
"In men, we observed that (a) higher UPF consumption was related to a higher risk of subfertility and a longer duration until pregnancy was achieved, but not with early embryo development," the first author said.
"This association may be explained by the sensitivity of sperm to dietary composition, whereas maternal UPF consumption may directly influence the environment in the womb in which the embryo develops from the start of life onwards," Lin said.
Gaillard suggested that a diet low in UPFs would be best for both partners, not only for their own health, but also for their chances of pregnancy and the healthy development of the unborn child.