New research published in the Journal of Clinical Investigation Insight finds that a typical Western-style diet high in fats is associated with decreased fertility.
The longitudinal study, led by scientists in the Oregon National Primate Research Center at Oregon Health & Science University, assessed the in vitro, via test tube, fertilization outcomes of female rhesus macaques while on a low-fat diet, and then again after transitioning to a Western-style diet consisting of a higher proportion of fat and refined sugar.
The collaborative research team, including Shawn Chavez, Ph.D., and Jon Hennebold, Ph.D., of the Division of Reproductive and Developmental Sciences, and Paul Kievit, Ph.D., of the Division of Cardiometabolic Health at OHSU, found that in the majority of the macaques observed, the transition to the Western-style diet increased weight gain and body fat as soon as 4-month post-intake.
“Interestingly, we did not observe a noticeable change in insulin levels,” says Hennebold, who is also an adjunct professor of obstetrics and gynecology, physiology and pharmacology in the OHSU School of Medicine. “However, we did identify a reduction of the anti-inflammatory protein IL1RA and the steroid cortisol in the ovary, which suggests that a maternal diet high in fats and carbohydrates can increase inflammation that is known to affect female fertility.”
After the transition to a Western-style diet, the ability of the animals to generate blastocysts, or embryos that would be capable of implantation, was significantly reduced. RNA-sequencing of blastocysts that did form, revealed that the Western-style diet caused significant changes in the expression of a variety of genes, including those involved in protein binding and cell adhesion processes necessary for successful embryo development.
Together, these results indicate that even short-term exposure to a Western-style diet can have a major negative effect on fertility and lower the likelihood of successfully undergoing infertility treatments. Additional assessment of the biological processes and signaling pathways of embryos exposed to a Western-style diet is necessary to help improve pregnancy outcomes in overweight individuals.
This research is supported by the National Institutes of Health Office of the Director (Grant P51 O5011092), and National Centers for Translational Research in Reproduction and Infertility (Grants R01HD020869 and P50 HD071836; Project II).