A new study points to a link between a healthy prenatal diet and how likely the child is to have autism — here’s everything you need to know.

It’s no secret that a healthy diet is best during pregnancy, it’s recommended by the NHS and midwives will recommend expectant mothers take prenatal vitamins.

However, new research shows it might be more important than we once thought and may actually influence how likely a child is to have autism.

Researchers looked at the data from two studies, making up over 96,000 mothers, and found those who followed a healthy diet reduced the risk of autism by 22%.

The healthy diet in those observed was made up of vegetables, fruits, nuts, fish, and whole grains, while high-fat foods, processed meats, soft drinks and refined carbohydrates were avoided.

Not only this, but the children were found to be less likely (by 24%) to develop ‘autism-associated traits’ such as social and communication difficulties (recorded at ages three and eight years), with the results more likely in girls. However, this wasn’t demonstrated in other autism-associated traits such as restrictive and repetitive behaviours.

How concerned should expectant mums be about their diet?

First and foremost, the researchers stressed: “At present, we remain uncertain as to whether the associations observed are causal,” and added that their findings were inconsistent with other research.

Fertility nutritionist Sophie Brockway (MSc, BSc, NTdip) says: “While these findings are promising, it’s important to continue monitoring emerging research. The link between diet and autism is complex, and ongoing studies will help refine dietary recommendations and clarify the mechanisms involved.

“Diet during pregnancy may influence the risk of autism, but it’s one of many factors that contribute to the condition — genetics also play a significant role in autism risk.”

Should pregnant women avoid ‘unhealthy’ foods at all costs?

While the study aligns with pre-existing advice to follow a healthy, balanced diet during pregnancy, Sophie notes: “Focusing on overall health and wellbeing during pregnancy, rather than specific nutrients or foods, is likely more beneficial.”

She also notes that the current research is inconsistent, as other studies have found no significant association.

Lesley Kumar, a registered dietician and certified nutrition specialist, adds that it’s about moderation: “You can indulge occasionally, but moderation is the key — you must balance it with healthy food choices.”

Where possible, she advises pregnant women limit their intake of processed foods, sugary drinks, food high in unhealthy fats and caffeine — the latter should be limited to no more than 200mg a day, according to the NHS.

The best prenatal diet including key vitamins and minerals

“Prioritise foods that provide essential nutrients for foetal development. These foods include lean proteins, leafy greens, whole grains and healthy fats,” says Lesley.

Many know that folic acid is important during pregnancy, as it’s crucial for neural tube development. What’s less commonly known is that, where possible, it’s best to begin supplementing folic acid prior to pregnancy to ensure levels are high.

“Some studies suggest adequate folic acid intake before conception and during early pregnancy may reduce the risk of autism,” says Sophie, who advises to find it in leafy greens, legumes and fortified foods.

“Low maternal vitamin D levels have been associated with an increased risk of autism,” she adds. A vitamin that plays a role in brain development and immune function, you can increase levels with sun exposure as well as eating fatty fish and fortified foods (fish consumption should be limited to just twice a week).

The third must-eat from Sophie is omega-3: “Deficiencies during pregnancy may be linked to an increased risk of neurodevelopmental disorders, including autism,” she explains. Find it in fatty fish (particularly salmon and mackerel), flaxseeds and chia seeds.

Along with these, Lesley also advises to focus on iron levels for blood volume and preventing anaemia (iron is found in lean meats, spinach, beans and supplements) and calcium, as it’s crucial for foetal bone development (found in dairy products, leafy greens and fortified plant milks), as well as increasing hydration.

While all these vitamins and minerals will be in prenatal supplements, eating them through diet is also essential.