Food allergy management warrants varied diet, expert says

Key takeaways:

• Children should follow diverse diets.
• Oral immunotherapy may impact nutritional intake.
• More research is needed to determine what diet is optimal for immune health.

BOSTON — Managing food allergies should involve more than just allergen avoidance, according to a presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.

“When we manage food allergy in the food allergy clinic, we sometimes need to think outside of the box and about what else is important other than just avoiding the allergens,” Carina Venter, PhD, RD, associate professor of pediatrics at the University of Colorado Denver School of Medicine, Children’s Hospital Colorado, said during her presentation.

When defining immunonutrition, Venter explained that it comes down to looking at food, food patterns, micro/macro nutrients and how they affect a person’s microbiome, epithelial barrier, metabolism and immune system.

Macronutrients

However, it is not certain what kind of nutrition is better for immune function, Venter noted. She showed the important functions of each macronutrient — protein, carbohydrates (including fiber) and fats — while emphasizing the limited research available for how they impact the immune system and allergy.

Carina Venter

A systematic review on fiber by Venter and colleagues found that different sources of fiber in randomized control trials were associated with better outcomes in allergic disease management. Venter commented that none of these trials included microbial analysis.

Fat was another nutrient on which Venter and colleagues conducted a systematic review.

“Fat is important for the epithelial barrier, the gut microbiome and the immune system,” Venter said. “With fat we have the conundrum where we know that high fat diets lead to reduced microbial diversity in the gut. But then we have omega 3 fatty acids, which is important for anti-inflammatory reactions.”

“So once again, we’re not really sure how much fat should we eat and which fats are most important,” she continued.

The review, which was done through the European Academy of Allergy, showed dietary fat or fatty acids may influence the development of inflammatory and genetic immune responses.

“Because of all the variations in the studies conducted and particularly the lack of pre-serum fatty acid levels prior to intervention, we weren’t able to make any conclusions,” Venter said.

She then highlighted the results of the LEAP study, where the active group consumed higher plant protein and had a higher fat and carbohydrate intake compared with the placebo group.

“The kids in the active group are eating peanut protein, and that’s probably why we saw such an effect in reduction in allergy outcomes,” Venter said. “But the active group also had a much healthier diet.”

The children in the active group also had higher plant-based fat intake, Venter said, and their carbohydrates came from healthy sources.

“So perhaps we just need to think about that as well,” she said.

Micronutrients

In terms of micronutrients, Venter cited a paper she recently published along with Franziska Roth-Walter, PhD, where she highlighted that in “apparently healthy individuals, deficiencies in iron, B6, vitamin A, vitamin E and vitamin D are associated with increased [C-reactive protein (CRP)] levels.”

“CRP is often how people measure inflammatory processes in the body, and it is fascinating to think that actually having these nutritional deficiencies can lead to increases in CRP levels and also other immune cells, which features acute phase response,” Venter said.

Inflammation

When food allergies occur, it can cause a pro-inflammatory state due to nutritional deficiencies, Venter said, citing a study by Roth-Walter and colleagues. At that point, a mucosal block takes place.

“Once you have these inflammatory processes, the body actually blocks absorption of nutrients via the normal digestive system,” she said. “To a great extent during inflammation, the best way to absorb micronutrients would be via the lymph system. And therefore, we need sufficient fat intake in the diet.”

Based on this study, Venter posed a question concerning children with chronic inflammation.

“Should we be thinking about higher fat, higher protein diets, lower carbohydrate diets and should we really be focusing on higher vitamin A and C and other antioxidants?” she asked.

Diet diversity

When discussing the effects of plant-based diets on immunity, Venter cited the American gut study by McDonald and colleagues, which showed that plant consumption was associated with a reduction in certain antibiotic resistance genes. They compared participants who consumed more than 30 types of plant-based foods a week with those who consumed 10 or fewer.

“Thirty plant-based foods are the ultimate combination of foods for a more diverse gut microbiome and better immune outcomes,” Venter said.

She explained that when trying to promote a diverse diet in infancy, many people believe that this diversification will result in obesity. Venter cited a paper she wrote with her colleagues that explored the question of whether a diverse diet does in fact lead to growth concerns.

“There was no evidence that an increased diverse diet in the first year of life is associated with obesity or overweight later in childhood,” she said.

Venter then noted that cooking also has a significant effect on immunity due to the advanced glycation end products (AGEs) produced by different cooking methods. She gave an example of how broiled chicken has 5,240 AGEs kU, whereas poached chicken has only 990 AGEs kU. Several observational studies showed that children who consume higher AGE-containing foods have more allergy outcomes, asthma, atopic dermatitis and eczema.

Peanut oral immunotherapy

Nutritional intake is affected by peanut oral immunotherapy, according to Venter.

“When we look at peanut OIT, when we feed children different forms of peanut, especially when we get to the higher dosages of 2 g twice a week or 3 g twice a week, it can affect their nutritional intake,” she said.

She presented a table that showed the different nutritional components of foods that included peanuts and pointed out that chocolate has the most sugar and salt along with U.S. cereals.

“We know from two small studies that children post-OIT may prefer more ultra-processed food,” Venter said. “In the study from Brazil, post-milk OIT children gained excessive weight.”

She cautioned against mixing OIT products with high sugar or high fat foods such as ice cream or protein mix with chocolate syrup.

However, when presenting data she published along with her colleagues, she showed that children undergoing OIT in the U.S. mostly mix their OIT dose with a sweet food.

“If we want to look at what the sweet foods are, it is chocolate, applesauce, yogurt, puddings, mousses and ice cream,” Venter said. “So, we really need to think about these OIT vehicles.”

Venter concluded that with allergen management, it is more than just allergen avoidance.

“Children should follow the varied diet,” she said. “Nutritional considerations should be taken into account when we use food ladders and OIT.”

References:

• McDonald D, et al. mSystems. 2018;doi:10.1128/mSystems.00031-18.
• Roth-Walter F, et al. Allergy. 2024;doi:10.1111/all.15972.
• Trevisonno J, et al. J Allergy Clin Immunol. 2024;doi:10.1016/j.jaip.2024.03.014.
• Venter C, et al. Allergy. 2021;doi:10.1111/all.14781.
• Venter C, at al. Allergy. 2021;doi:10.1111/all.14949.
• Venter C, at al. Allergy. 2022;doi:10.1111/all.15430.
• Venter C, at al. J Allergy Clin Immunol. 2016;doi:10.1016/j.jaci.2016.08.001.
• Venter C, et al. Pediatr Allergy Immunol. 2024;doi:10.1111/pai.14100.

For more information:

Carina Venter, PhD, RD, can be reached at carina.venter@childrenscolorado.org.