Foods rich in essential nutrients for growth and development often contain the most common allergens. Children with dietary restrictions, particularly children with cow's milk allergy (CMA) or multiple food allergies (FAs), are at risk for vitamin D and other nutrient deficiencies.

Study Highlights

• This study at an academic pediatric allergy practice compared markers of vitamin D and iron status of youths aged 0.5 to 17 years with CMA (n = 77), other FAs (n = 70), and atopy without FAs (n = 87).
• The impact of CMA and other FAs on vitamin D levels and iron markers was analyzed using multiple linear regression.
• Vitamin D insufficiency occurred in 32% of children with CMA, 39% of children with other FAs, and 37% of children without FAs.
• Vitamin D deficiency occurred in 23%, 23%, and 13%, respectively.
• Vitamin D levels were associated with vitamin D supplementation (P < .001) and intake of breast milk, CM, infant formula, or plant-based milk beverage but not with CMA or other FAs.
• The highest risk for vitamin D insufficiency (83%) was in older children (age > 10 years) with any FA who did not consume any CM or alternative milk beverage.
• Children with CMA had a higher rate of IDA (8%) than children with other FAs (1%) or children without FAs (5%, P < .001).
• Mean transferrin saturation and iron levels were significantly lower in children with other FAs (22.7% and 66.6 μg/dL, respectively) than in children without FAs (28%, P = .004; 79.7 μg/dL, P = .026, respectively).
• Prevalence of iron deficiency without associated anaemia (low levels of transferrin saturation) was higher in children with CMA (32%) and other FAs (37%) than in children without FAs (17%, P = .013).
• The investigators concluded that vitamin D deficiency and insufficiency are common in children with atopy, regardless of FA, but that children with CMA are at higher risk for IDA, and children with other FAs had lower iron and transferrin saturation levels.
• FAs may result in nutrient deficiencies through dietary restriction, and vitamin D deficiency may also contribute to the development of allergies, but the impact of vitamin D on the risk for food allergen sensitization is unclear, given contradictory evidence in the reported literature.
• FAs may also increase the risk for zinc and vitamin B6 deficiencies.
• Older children on elimination diets for longer periods, in whom CM alternative is often considered nonessential, had the highest rate of vitamin D insufficiency.
• Even though these children may have “outgrown” their CMA, they may have not incorporated CM back into their diet because of preference.
• Possible increased risk for IDA in children with CMA is interesting, as CM is not a good source of iron.
• To optimize nutritional status in children avoiding CM, the investigators recommend intensive nutritional counselling of patients and families with FAs, using a registered dietician if needed, and nutrient intake monitoring, specifically for vitamin D and iron.
• Clinicians and dietitians should help reduce pediatric nutrient deficiencies by encouraging a varied diet and early introduction of diverse foods in the first year of life and should guide families on how to substitute foods eliminated from the diet with safe alternatives having equivalent nutritional content.

Clinical Implications

• Children with CMA are at higher risk for IDA, and children with other FAs had lower iron and transferrin saturation levels.
• Patients and families with FAs should receive intensive nutritional counselling and nutrient intake monitoring.
• Implications for the Healthcare Team: Members of the healthcare team should guide families on how to substitute foods eliminated from the diet with safe alternatives having equivalent nutritional content.