Can the Western Diet During Pregnancy Increase ADHD, Autism Risks?

New research has found significant links between Western dietary patterns during pregnancy and ADHD and autism. While a whole foods diet is a better option, experts say one specific nutrient may be equally critical for healthy prenatal brain development.

Estimates indicate that in 2022, 7 million children in the United States aged 3 to 17 years had attention deficit hyperactivity disorder (ADHD) — one million more than in 2016. Moreover, the latest Centers for Disease Control and Prevention (CDC) data shows that one in 36 children has autism spectrum disorder, up from one in 44 in 2018.

The rapid increases in ADHD and autism rates have sparked a sense of urgency among scientists and health officials to identify the cause of both neurodevelopmental conditions.

While genetics and environmental factors may play a role, the reasons behind the rise in ADHD and autism among children are likely a combination of factors, making it challenging for scientists to pin down the exact cause.

Recently, researchers revealed evidence that consuming the Western diet, AKA the Standard American Diet, during pregnancy may contribute to children developing ADHD and autism. This common dietary pattern typically includes ultra-processed foods, refined grains, processed meat, high-sugar drinks, candy, sweets, and fried foods. The scientists found that even small shifts towards this eating pattern were linked to a significantly higher risk of these conditions.

While more research is needed, WellnessPulse spoke with experts who said that moving away from the Western diet and consuming whole foods during pregnancy is beneficial for both mother and baby. However, both dietary patterns can lack choline — a nutrient that experts say may help reduce the risk of neurodevelopmental conditions like ADHD and autism.

Links between the Western diet, ADHD, and autism

In the clinical study published on March 3 in Nature Metabolism, scientists from Denmark analyzed self-reported maternal dietary patterns at 24 weeks of pregnancy, then looked at whether the resulting children had a neurodevelopmental disorder diagnosis at 10 years of age. The research included more than 60,000 mother-child pairs.

The results showed that children born to mothers who followed a Western dietary pattern, even moderately, had a 66% increased risk of ADHD and a 122% higher risk of autism. Moreover, the link between maternal Western diet consumption and the risk of ADHD and autism persisted even after the researchers accounted for factors associated with these conditions, including genetics.

"The greater a woman's adherence to a Western diet in pregnancy — high in fat, sugar, and refined products while low in fish, vegetables, and fruit — the greater the risk appears to be for her child developing ADHD or autism," said lead study author, David Horner, MD, PhD, in a University of Copenhagen news release.

The team also analyzed the mother's blood samples and found 43 specific metabolites associated with the Western diet that could help explain the link between diet and neurodevelopmental disorders.

Metabolites in question include those in deep-fried foods, processed meats, and margarine.

The research team found that 15 of these 43 metabolites, which play a role in inflammation and oxidative stress regulation, were specifically linked to a higher risk of ADHD.

While the study does not prove the Western diet causes ADHD or autism, it does raise questions about whether dietary choices during pregnancy can either positively or negatively influence brain development in an unborn child.

Can dietary choices during pregnancy lower the risk of ADHD and autism?

U.S. dietary guidelines encourage pregnant or breastfeeding women to follow a healthy diet that includes vegetables, fruits, whole grains, and protein sources such as eggs, meat, or fish that have low mercury levels, such as cod.

Pregnant or lactating women may also need vitamin supplements to meet increased nutritional demands. Experts advise limiting added sugars, saturated fat, and sodium.

However, dietary guideline data shows that 70–88% of pregnant women in the U.S. exceed the recommended limits for sugar, saturated fat, or sodium intake.

According to Julia McQueen, MPH, RD, LDN, a Registered Dietitian at Julia McQueen Nutrition, LLC, most information about optimal diets during pregnancy comes from observational studies. While there may be a link between a specific dietary pattern and neurodevelopmental conditions, it may not be a direct cause and effect.

There are a lot of other factors to consider that are difficult to control for, including maternal stress, low income, food insecurity, lack of support, [and the] nature of dietary recalls. ADHD and autism have a strong genetic component as well, which even this study discusses.

Julia McQueen, MPH, RD, LDN

Still, she suggests that the best diet for a pregnant woman is a well-balanced eating pattern that does not restrict any key food groups.

"A diet that emphasizes plenty of fruits, vegetables, whole grains, healthy fats, beans and legumes, and lean proteins is ideal," McQueen explains. "Limiting added sugars, heavily processed foods (think frozen dinners, not necessarily the pre-mixed salad kit), and alcohol protects a baby's brain development."

However, McQueen urges caution when consuming fish, as some species are high in mercury, which can harm fetal brain development. High-mercury fish tend to be larger and older fish higher up the food chain, such as king mackerel, swordfish, and bigeye tuna.

Choline may be key for a baby's brain development

While incorporating whole, nutrient-dense foods into the diet during pregnancy is essential, McQueen says that choline, a nutrient present in some foods and available as a dietary supplement, is also critical.

"Less talked about but vitally important is choline, an essential [nutrient] for healthy fetal brain development," McQueen notes. "Research is still being done on the exact level of supplementation needed, but there is evidence that most mother's intake is inadequate. In addition, due to its "bulky" nature, most prenatal vitamins contain only small amounts of choline, if at all."

Robert Freedman, MD, Professor of Psychiatry and Pharmacology at the University of Colorado School of Medicine and a member of the National Academy of Medicine, tells WellnessPulse that choline is one of the primary dietary ingredients that may help prevent mental or neurodevelopmental problems in childhood.

Choline is commonly deficient only in women and only during pregnancy, especially in the second trimester when the baby and placenta are starting to grow more noticeably. Large amounts of choline form the outer wall of each new fetal cell, and choline also activates key steps in fetal brain development that have [a] lifelong impact on the child's mental well-being.

Robert Freedman, MD

Freedman explains that although the placenta actively delivers choline to the fetus to help meet the demand, many women don't consume enough to meet the Adequate Intake (AI) levels recommended by health experts.

Freedman says that most women would need to consume six to eight servings of eggs (yolks) and red meat daily to reach optimal levels for fetal development.

"Women with higher choline levels, including from prenatal choline supplements in our randomized clinical trials, have fewer underweight and preterm babies, support better fetal brain development, and decrease their child's risk for attention deficit and social withdrawal problems that are early signs of attention deficit disorder, autism spectrum disorder, bipolar disorder, and schizophrenia," Freedman concludes.

Final thoughts

During pregnancy, many women worry they are not doing enough to ensure their baby is born as healthy as possible. And new studies that suggest certain dietary choices may negatively impact prenatal development may only amplify their concerns.

"It's important to remember that there's a lot of pressure on moms to get everything perfectly, including nutrition," McQueen says. "As a dietitian specializing in the perinatal space, I certainly don't think pregnant [women] need to eat perfectly in order to be the best parent or to have a healthy outcome for their baby."

She suggests that other factors can influence a baby's neurodevelopment.

"Nutrition is an important factor to baby's brain development," McQueen says. "But even more important is adequate prenatal care, access to healthy foods, addressing food insecurity by connecting eligible families to WIC (Women, Infants, and Nutrition program), and public health policies that support families through preconception, pregnancy, lactation if applicable, and the critical first three years of a child's life for brain development."