Increased food diversity in the first year of life is inversely associated with allergic diseases

Timing and diversity of complementary food introduction for prevention of allergic diseases. How early and how much?

“…Gene expression analysis was performed in relation to food diversity as a novel approach to increase our understanding of the mechanisms inducing tolerance. Increased food diversity was associated with an increased expression of forkhead box protein 3 and a decreased expression of Ce germline transcript [8]. However, significant differences were found only in a very small subgroup of 22 children, 15 of which had an allergic parent and who were exposed to no more than three food items by 1 year of age.…”

“…When (even insufficient) adjustment for reverse causation was considered, the presumably protective effects were attenuated. Furthermore, the results were no longer statistically significant when the extreme group of infants which were given less than four food items until the age of 12 months (<5 % of the study population) were excluded ( Table 2 in [8]). Gene expression analysis was performed in relation to food diversity as a novel approach to increase our understanding of the mechanisms inducing tolerance.…”

“…This controversy was recently stimulated by two published papers using data from two cohort studies, the PASTURE/EFRAIM study [8,9] and the DIPP study [10,11]. The results of these publications have been interpreted as evidence that the introduction of complementary feeds prior to age 4 months has allergy-preventive effects.…”

“…In their first paper on atopic dermatitis, the authors stratified the analysis by skin symptoms early in life to reduce the likelihood of reverse causation [9]. However, in their most recent paper examining the impact of solid feeding during infancy on respiratory allergies until age 6 years, the authors only excluded children whose respective end points had occurred before solid food introduction [8]. This analytic strategy may be insufficient to exclude reverse causality as eczema during the first 6 months of life is closely associated with later asthma and allergic rhinitis.…”

“…However, even some of these more recent studies did not consider possible reverse causation [12] and hence must be interpreted with caution. Some authors considered an adjustment for medical history of allergic diseases to be sufficient [8,10], while more cautiously performed analyses excluded children with early skin symptoms [5,6,9,14]. Most of the presumed protective effects relating to the timing of solid food introduction were no longer statistically significant if subjects with early skin symptoms were excluded [5,6,8,14].…”