Researchers looked at 28 studies to understand how a mother’s diet during pregnancy might affect whether her child develops allergies. They found that eating a variety of healthy foods during pregnancy may help protect babies from food allergies. They also discovered that diets high in inflammatory foods (foods that cause swelling in the body) might increase the risk of asthma and wheezing in young children. While these findings are promising, the researchers say we need more studies to fully understand how important diet really is for preventing childhood allergies.

The Quick Take

  • What they studied: Whether what pregnant women eat affects their children’s chances of developing allergies, asthma, eczema, and other allergy-related conditions
  • Who participated: This review combined information from 28 different research studies that looked at thousands of pregnant women and their children across multiple countries
  • Key finding: Eating a variety of different healthy foods during pregnancy showed a small but real protective effect against food allergies in children. Additionally, diets that cause inflammation in the body were linked to higher rates of asthma and wheezing in young children.
  • What it means for you: Pregnant women may want to focus on eating a diverse, balanced diet with many different healthy foods. However, this research shows only modest effects, so diet is likely just one of many factors that influence whether a child develops allergies. Talk to your doctor about your specific diet during pregnancy.

The Research Details

Researchers searched four major medical databases for all studies published through November 2024 that looked at how pregnant women’s eating patterns affected their children’s allergies. They included 28 papers that examined different types of diets—some healthy, some unhealthy—and tracked whether children developed allergies, asthma, eczema, or food sensitivities.

The researchers used a special tool called ROBINS-I to check the quality and reliability of each study. When multiple studies looked at the same diet pattern and allergy outcome, they combined the results using statistical methods called meta-analysis. This approach allowed them to see patterns across many studies rather than relying on just one.

The review focused on overall eating patterns rather than single foods or nutrients, which is important because how foods work together in a diet may matter more than individual items.

Looking at overall diet patterns is more realistic than studying single nutrients because people don’t eat foods in isolation—they eat meals made of many ingredients. This approach helps researchers understand what actually happens in real life. By combining results from multiple studies, researchers can spot patterns that might not be obvious in a single study, making the findings more reliable and trustworthy.

This is a systematic review, which is considered high-quality research because it carefully examines all available studies on a topic. The researchers used standard tools to check each study’s quality and used proper statistical methods to combine results. However, the individual studies they reviewed had varying quality levels, and some results showed high heterogeneity (meaning studies disagreed with each other), which suggests we should be cautious about the strength of some findings.

What the Results Show

The most important finding was that eating a variety of different foods during pregnancy showed a small protective effect against food allergies in children. For every additional type of food a pregnant woman ate, the odds of her child developing a food allergy decreased slightly (by about 5%).

The second major finding involved inflammatory diets—diets high in processed foods, sugar, and unhealthy fats that cause swelling in the body. Children whose mothers ate these types of diets during pregnancy had higher rates of asthma and wheezing before age 5. Specifically, children exposed to pro-inflammatory diets had about 17-18% higher risk of developing asthma or wheezing.

Interestingly, while researchers looked at many other diet patterns (like Mediterranean diets, Western diets, and overall healthy eating patterns), most of these showed no clear connection to allergies. Only one diet index called the Maternal Diet Index showed connections to multiple allergy outcomes, but this needs to be studied more.

The review examined connections between maternal diet and several allergy-related conditions including eczema, allergic rhinitis (hay fever), and general allergic sensitization (when the body becomes sensitive to allergens). However, most diet patterns showed no clear protective or harmful effects on these conditions. This suggests that diet may be more important for preventing food allergies and asthma specifically, rather than other types of allergies.

This review builds on earlier research suggesting that diet during pregnancy matters for child health. Previous studies hinted that specific nutrients and foods might help prevent allergies, but this review shows that the overall pattern of eating—especially eating variety and avoiding inflammatory foods—may be what really counts. The findings align with growing evidence that inflammation plays a role in childhood asthma development.

The researchers found several important limitations. Many studies had different designs and measured things differently, making it hard to compare results directly. Some studies had small numbers of participants or didn’t carefully control for other factors that might affect allergies (like genetics or air pollution). The protective effect of diet diversity was modest, meaning diet is probably just one piece of the puzzle. Most studies came from wealthy countries, so we don’t know if these findings apply everywhere. Finally, the researchers couldn’t prove that diet causes these allergy differences—only that they’re connected.

The Bottom Line

Pregnant women should aim to eat a diverse diet with many different types of healthy foods including fruits, vegetables, whole grains, and lean proteins (moderate confidence). Women should try to limit processed foods, added sugars, and unhealthy fats, which may reduce inflammation and potentially lower their child’s asthma risk (modest confidence). These recommendations are based on current evidence but should be combined with other healthy pregnancy practices and discussed with healthcare providers.

Pregnant women and those planning pregnancy should pay attention to these findings, especially if they have a family history of allergies or asthma. Women with existing inflammatory conditions may find this particularly relevant. However, these findings don’t mean diet is the only factor—genetics, environment, and other factors also play important roles. People without family history of allergies shouldn’t feel pressured to make major diet changes based solely on this research.

If a pregnant woman changes her diet to be more diverse and less inflammatory, any protective effects would likely develop during pregnancy and become apparent in the child’s first few years of life. Most allergy and asthma symptoms appear before age 5, so this is the critical window. However, diet changes take time to show effects, and some children may still develop allergies regardless of maternal diet.

Want to Apply This Research?

  • Track the number of different food groups eaten each day during pregnancy (aim for at least 5-7 different types: fruits, vegetables, whole grains, proteins, dairy, nuts/seeds, and healthy oils). Log weekly to monitor dietary diversity trends.
  • Use the app to plan weekly meals that include foods from different categories. Set reminders to try one new healthy food each week. Create a shopping list feature that ensures variety across food groups rather than repetitive meals.
  • Track dietary diversity scores weekly throughout pregnancy. Create a dashboard showing progress toward variety goals. After birth, correlate dietary patterns with child’s allergy symptoms (eczema, food reactions, wheezing) to see personal patterns. Share data with healthcare provider at prenatal visits.

This research suggests associations between maternal diet and childhood allergies but does not prove that diet alone causes or prevents allergies. Pregnancy nutrition is complex and individual needs vary. Pregnant women should consult with their healthcare provider or registered dietitian before making significant dietary changes. This information is for educational purposes and should not replace professional medical advice. Allergy development is influenced by many factors including genetics, environment, and infections—diet is just one piece of the puzzle.