Nutrient Supplementation and Atopic Dermatitis

Abstract

Source: Foolad N, Brezinski EA, Chase EP, et al. Effect of nutrient supplementation on atopic dermatitis in children. JAMA Dermatol. 2013; 149(3): 350-355; doi: 10.1001/jamadermatol.2013.1495Investigators from the University of California at Davis performed a systematic literature review to determine the impact of nutrient supplementation on the prevention or reduction in severity of atopic dermatitis (AD) in children. The investigators searched the Cochrane Central Register of Controlled Trials, MEDLINE, and the Latin American and Caribbean Health Science Literature databases for clinical trials and cohort studies published between 1946 and 2012. For inclusion, studies needed to involve children <3 years old with or at risk for AD, and report the prevalence, incidence, or AD severity. Studies that met selection criteria were independently reviewed by 2 investigators. Data abstracted from each study included type of nutrient and primary outcome measures. The risk of bias for all included studies was also assessed.There were 21 studies that met selection criteria, 20 of which were randomized controlled trials. The studies included 6,859 participants, infants or mothers who were pregnant or breastfeeding, who received nutrient supplementation; there were 4,134 controls. Selected studies examined the effect of 4 different nutrient supplementations: probiotics, prebiotics, formula, and fatty acids. There was a low risk of bias among the selected studies.Of the 21 selected studies, nutrient supplementation was found to prevent the development of AD in 11 of 17 studies and decrease the severity of AD in 5 of 6 studies. Specifically, 6 of 10 studies on the effect of probiotics found that they reduced the incidence of AD. The results of other included studies suggested that partially hydrolyzed whey and extensively hydrolyzed casein formulas were effective in preventing the development of AD, especially among infants without a family history. Certain fatty acids, such as γ-linolenic acid, reduced AD severity but not its development, while prebiotics reduced AD incidence but not severity.The investigators conclude that certain nutrient supplements appear to decrease AD incidence and severity, but further research is needed to validate these findings and determine their mechanism of action.Dr Wright has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.The incidence of AD in infants has increased and reached an estimated 20% over the past 30 years.1 Multiple studies have attempted to examine the effects of dietary nutrient supplementation on the development and severity of AD. To date, this topic has been somewhat controversial and study designs and conclusions have varied. This review summarizes the results of 20 randomized controlled trials addressing this question. Although not all included studies found nutrient supplementation to be helpful in decreasing the incidence and/or severity of AD, many did. Interventions with the most compelling supporting evidence used supplementation with certain probiotics.Although these conclusions are certainly intriguing, no studies to date have adequately addressed the question of mechanism of action for nutritional supplementation. Also, no studies have established a causal link between ingestion of certain nutrients, concomitant changes in the intestinal flora, and positive effects on the frequency and severity of AD. Further studies are needed to investigate these questions, as well as to establish whether nutrient supplementation has any lasting preventive effects. In addition, if the benefits of nutrient supplementation are further confirmed, recommended guidelines for nutrient supplementation will need to be established.