Food diversity in first year of life leads to fewer allergies in second year

Infants who ate a more diverse diet during their first year had lower risk for allergic diseases during their second year, according to a study published in Pediatric Allergy and Immunology.

Chunrong Zhong, PhD, of Tongji Medical College at Huazhong University of Science and Technology in Wuhan, China, and colleagues surveyed 2,251 women who gave birth to singleton live infants at 1, 3, 6, 12 and 24 months after birth.

The women were asked about breastfeeding, use of formula, complementary foods introduced and history of food allergies among their infants. The researchers then assessed food diversity by the number of food groups introduced to each infant.

For the 6-month interview, the researchers categorized complementary foods into cereal, vegetable, fruit, meat, fish and egg groups. They found that 44% of the infants had been introduced to three to six of these groups. Cereals represented the most introduced food group, followed by fruits, egg yolk and vegetables.

Children who had not been introduced to any complementary foods by age 6 months had an increased risk for allergic diseases (adjusted OR = 2.19; 95% CI, 1.06-4.54), particularly allergic diseases involving skin (adjusted OR = 3.22; 95% CI, 1.25-8.27), during their second year of life, compared with children who had been introduced to three to six food groups by age 6 months.

For the 12-month interview, researchers expanded the food groups to include cereals, vegetables, fruits, meats, fish and seafoods, eggs, beans, peanuts, other nuts, milk and milk products, and sweets. Zhong and colleagues found that 48.1% of the infants had been introduced to eight to 11 of these groups. Also, almost all the infants had been introduced to cereals, vegetables, fruits, eggs and meats, although peanuts and other nuts were introduced less often.

In models adjusted for food allergy history of infants and other potential confounders, the researchers found significant inverse dose-response relationships with food diversity by 12 months of age and later allergic diseases (1-5 food groups vs. 8-11, adjusted OR = 1.87; 95% CI, 1.01-3.48; 6-7 food groups vs. 8-11, adjusted OR = 1.64; 95% CI, 1.12-2.4), especially when those diseases involved the respiratory tract (1-5 food groups vs. 8-11, adjusted OR = 2.35; 95% CI, 1.03-5.32; 6-7 food groups vs. 8-11, adjusted OR 1.98; 95% CI, 1.16-3.37). Infants only exposed to one to five food groups by 12 months of age also had an increased odds of food allergy during 1 to 2 years of age (adjusted OR = 2.1; 95% CI, 1.29-3.42).

In fact, the researchers wrote, each additional food group introduced by age 6 months reduced the risk for allergic diseases during the second year by 15% (OR = 0.85; 95% CI, 0.73-1.00). Each additional food group introduced by age 12 months reduced the risk for later allergic diseases by 15% (OR = 0.85; 95% CI, 0.75-0.95) and the risk for later food allergy by 12% (OR = 0.88; 95% CI, 0.79-0.98).

Overall, infants with lower diversity of foods in any period had a greater risk for later allergic diseases, including allergic diseases involving the respiratory tract and allergic diseases involving skin, than those infants with higher diversity of foods in both periods.