Ultra-Processed Foods May Impact Fertility

While many fertility experts already counsel their patients to eat a healthy diet, advice has largely centered around the woman’s food choices.

“Our findings suggest, for the first time, that ultra-processed food consumption in future parents” — meaning women and men — “is associated with the chances of becoming pregnant and early development of offspring,” says study coauthor Romy Gaillard, MD, PhD, a pediatrician and associate professor of developmental epidemiology at Erasmus University Medical Center in Rotterdam, the Netherlands.

Here’s what may be causing this link, plus what reproductive endocrinologists want you to keep in mind about diet while trying to conceive.

The Study Uncovered More Than One Fertility Issue Stemming From Ultra-Processed Foods

Published in the journal Human Reproduction, the study analyzed data from about 800 women and 650 male partners who were enrolled in a population-based study that followed parents from conception, through pregnancy, and into their children’s early years.

The researchers collected data on the parents’ diets through questionnaires answered during early pregnancy (around 12 weeks).

Researchers calculated that ultra-processed foods, as a percentage of participants’ total daily food intake, accounted for 22 percent for women and 25 percent for men on average.

The questionnaires also gave the researchers information on how long it took the participants to conceive, how likely they were to conceive within a month, and subfertility, which is trouble conceiving within 12 months or the use of assisted reproductive technology.

The researchers had access to ultrasound data gathered at 7, 9, and 11 weeks of gestation. This allowed the researchers to analyze information about the fetus, including the distance between the embryo’s head and its buttocks (which suggests size and development) and the volume of the yolk sac.

The researchers discovered that, for women, eating more ultra-processed food wasn’t linked to trouble conceiving, but it was linked with a slightly smaller growth of the embryo and yolk sac size by seven weeks of pregnancy. (This can be associated with a higher risk of negative outcomes, including premature birth, low birth weight, and an increased risk of miscarriage.)

For men, eating more ultra-processed food was linked to greater odds of subfertility.

“These differences were small, but are important from a research perspective and on a population level, as the consumption of ultra-processed foods has rapidly increased worldwide,” Dr. Gaillard says.

“Our findings highlight the importance of involving both the mother-to-be and father-to-be in preconception counseling, as health and lifestyle of women and men play an important role in reproductive outcomes,” Gaillard says. “It is likely easier to make sustainable lifestyle changes as a couple.”

It’s important to note that the participants were relatively healthy, making it hard to generalize the findings to high-risk groups. The study was also observational, making it difficult to say that eating ultra-processed foods directly caused these outcomes. Instead, the findings only show a link.

The New Research Supports Earlier Findings

Fertility is a complicated process, making it hard to say that diet alone will increase or decrease a person’s ability to conceive, says Josette C. Dawkins, MD, a reproductive endocrinologist at Boston IVF in Springfield, Massachusetts. However, the latest findings echo earlier studies linking ultra-processed foods to the ability to get pregnant, she says.

How Diet May Impact Conception for Men and Women

Dietary choices can influence fertility in a few ways. “Diet plays an important role in influencing hormone production, egg and sperm quality, and overall reproductive health,” says Dr. Dawkins, who wasn’t involved in the study.

“For men, zinc, antioxidants, and healthy fats improve sperm quality,” she says. “For women, nutrients like folate, vitamin D, and omega-3s support egg quality and hormone balance, and protect the eggs from oxidative stress.”

Eating more ultra-processed foods means people are eating less whole foods that can provide these important nutrients. “These processed foods are not only pro-inflammatory, but also lack key antioxidants such as omega-3 which are important in reducing oxidative stress,” Dawkins says. That can interfere with sperm DNA and egg quality, she adds.

Eating too many refined sugars, a common feature of many ultra-processed foods, can lead to insulin resistance and hormonal imbalances, according to Sara Mucowski, MD, a reproductive endocrinologist and ob-gyn at Dallas IVF, an Ivy Fertility Center in Texas.

“Furthermore, chronic inflammation that may be a result of continued exposure to ultra-processed foods may impair development of sperm and/or eggs, as well as making the uterine environment less hospitable,” says Dr. Mucowski, who wasn’t involved in the study. Ultra-processed foods also tend to be low in fiber, which can interfere with gut health and fuel inflammation, causing more issues with fertility, she adds.

Finally, ultra-processed foods can contribute to overweight and obesity “which accelerates all of the above,” says Alex Robles, MD, reproductive endocrinologist at Columbia University Fertility Center in New York City.

More research is needed to determine exactly why ultra-processed foods may impact fertility, Gaillard says.

Why Fertility Specialists Emphasize Optimal Nutrition

“Because we are what we eat, it is important that we provide our bodies with the nutrition it needs to function optimally,” says Mucowski. “I recommend that my patients who are trying to conceive focus on whole foods and lean proteins, especially those with omega-3 fatty acids, antioxidants, and high-fiber carbohydrates.”

It’s important that both partners consider their diets, Dr. Robles says. “While this study shows associations rather than causation, it reinforces the importance of a balanced, nutrient-rich diet when trying to conceive,” he says. “Reducing intake of ultra-processed foods and focusing on whole, minimally processed options is a practical step couples can take to support their fertility and early pregnancy health.”

Mucowski says that patients don’t need to completely eliminate ultra-processed foods from their diet. Instead, she suggests that patients try to get at least 80 percent of their food intake from minimally processed foods.

“Please pay attention to nutrients, such as folate, vitamin D, antioxidants, and omega-3s,” Dawkins says. “Limit refined sugars, unhealthy fat, and excessive alcohol.”

But fertility specialists stress that dietary changes will only do so much for conception. “In everything, consult a fertility specialist, as a healthy diet alone will not overcome a medical cause for infertility,” Dawkins says.