Infants with a diverse diet at age 9 months were less likely to develop food allergy by age 18 months, especially if they had a history of eczema, according to a study published by Pediatric Allergy and Immunology. Infants with no family history of food allergy also saw further reduced risks for food allergy with a diverse diet at 9 months, Stina Bodén, PhD, postdoctoral researcher, department of clinical sciences, pediatrics, Umeå University, and colleagues wrote.
“There are reports that timing, dosage, interval, and regularity of allergen ingestion can all influence the development of oral tolerance,” Bodén told Healio.“However, no study has previously studied consumption frequency of diverse diet in infancy, which is why our study was the first to incorporate the meaning of frequency of intake within a diverse diet for food allergy prevention,” she continued. The research used data from 2,060 infants in the NorthPop Birth Cohort Study. When these infants were approximately age 9 months, their parents answered a questionnaire about how frequently they consumed 55 food items and about when they were introduced to 41 food items.
At age 18 months, 100 (4.9%) of the infants had a food allergy diagnosis as reported by their parents. Allergies included cow’s milk (n = 69), egg (n = 35), wheat (n = 7), peanut (n = 7), soy (n = 4), tree nut (n = 3) and fish (n = 1). Also, 30 infants had more than one food allergy, and 98 of them had ingested the allergen before they were diagnosed. Nearly all the infants who did not have a parental reported food allergy diagnosis (98.9%) had been introduced to four to six allergens before age 18 months.
Weighted diet diversity scores were based on how frequently the infants consumed 14 foods at age 9 months, using present Swedish guidelines for feeding infants, as well as on whether 14 foods and six allergenic foods had been introduced at ages 6 and 9 months. Generally, higher weighted diet diversity scores at age 9 months were associated with lower odds for food allergy at age 18 months, the researchers said, although they did not categorize these associations as statistically significant. But specifically, the odds for food allergy at 18 months were 61% lower for infants with the highest diet diversity scores (24-31 points) compared with infants with the lowest diet diversity scores (0-10 points), after full adjustment, which the researchers said was statistically significant (P = .023).
Diet diversity scores and food allergy were not associated at age 9 months, but results remained significant although limited by power for weighted diet diversity scores in a sensitivity analysis for risk for food allergy at age 18 months that excluded 48 infants who had a food allergy diagnosis at age 9 months (OR = 0.24; 95% CI, 0.07-0.83). The unadjusted odds ratio for diversity of foods introduced at age 6 months exceeded 1, indicating no association with a reduced subsequent risk for food allergy. The odds ratio in a fully adjusted multivariable model for 13 or 14 introduced foods was 0.99 (95% CI, 0.51-1.91) compared with seven or fewer introduced foods.
The introduction of 13 or 14 foods at age 9 months was associated with a 45% decrease in odds for food allergy (OR = 0.55; 95% CI, 0.31-0.98) compared with the introduction of 10 or fewer foods in the fully adjusted multivariable model as well. The researchers did not report any association between food allergy at age 9 months and diversity of introduced foods at age 6 months or at age 9 months. When the researchers excluded from the analysis 33 infants with food allergy at age 18 months who only experienced gastrointestinal symptoms to reduce risks for diagnostic misclassification, results for the highest diet diversity at age 9 months remained significant.
Higher risks for food allergy also were statistically significantly associated with breastmilk and formula diets (OR = 1.77; 95% CI, 1.03-3.05) and exclusive formula diets (OR = 1.89; 95% CI, 1.12-3.18) compared with exclusive breastmilk diets, all at age 4 months, in fully adjusted models based on the applied directed acrylic graph model. Infants with the highest weighted diet diversity scores at age 9 months and no food allergy in their family history had a potential reduction in risk for food allergy (OR = 0.29; 95% CI, 0.08-0.99).
The researchers further found significant associations between weighted diet diversity scores and food allergy at age 18 months (OR per 1 unit increase = 0.93; 95% CI, 0.87-1) among children with a history of eczema in the multivariable model, which was “interesting,” Bodén said. “This finding strengthens the dual allergen exposure hypothesis with regard to early oral multiple food exposure,” Bodén said. “Hence, children with eczema may benefit the most from eating a diverse diet in infancy.”
Based on these findings, the researchers concluded that children with a high weighted diet diversity score at 9 months were at less risk for food allergy at 18 months, especially if they had a history of eczema or no family history of food allergy. Doctors should encourage caregivers to introduce a variety of foods to their children early in life to train their preferences for taste and texture, providing infants with small tastes of what caregivers are eating but avoiding sugary products, Bodén said. “Wait 3 to 5 days between each new food. Really slow down the process of diversifying the infant’s diet. Expand the type and number of vegetables and pulses in your daily cooking, and finally and importantly, make weekly meal plans,” Bodén said. “By doing this, the probability to achieve a diverse diet for the whole family increases.”
