• There has been a significant increase in childhood prevalence of peanut or tree nut (P/TN) allergies. In this prospective cohort study (part of the ongoing Nurses’ Health Study II and Growing Up Today Study 2), the offspring of mothers who documented their peripregnancy dietary intake were assessed for P/TN allergies. Of 8205 children, 140 cases of P/TN allergies were documented. Offspring of nonallergic mothers who consumed more P/TN during the peripregnancy period were statistically less likely to develop P/TN allergies than children of mothers who consumed less (P = .004).

• This study indicates that early allergen exposure (even during the peripregnancy period) can lower the risk of childhood food all

Commentary By:  David Rakel MD, FAAFP

The Earlier the Better

There has been controversy in the literature about the timing of maternal nut intake and associated allergy in their offspring. This study did not look at when these foods were given to the child but when the mother consumed them. It appears that those mothers who ate the most peanuts and tree nuts around the time of pregnancy had offspring with the least amount of allergy to these foods. This suggests that early allergen exposure increases the likelihood of tolerance, reducing the child’s risk. It should be noted that those mothers who ate more peanuts and tree nuts also ate a more nutritious diet overall, with more vegetables and fruit. This may suggest that eating a healthier diet may also be playing a factor in the child’s allergy risk.

The power of maternal nutrition is seen in epigenetic research of agouti mice. These animals are bread to be genetically susceptible to developing diabetes and become overweight with a yellow color to their coat. But when the mothers of these agouti mice are fed foods (beets, onions, garlic) that influence methylation, their offspring remain thin, have a brown coat, and don’t develop diabetes (agouti mice)The mother’s diet keeps the diabetes gene from being phenotypically expressed!

ABSTRACT

IMPORTANCE

The etiology of the increasing childhood prevalence of peanut or tree nut (P/TN) allergy is unknown.

OBJECTIVE

To examine the association between peripregnancy consumption of P/TN by mothers and the risk of P/TN allergy in their offspring.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study. The 10 907 participants in the Growing Up Today Study 2, born between January 1, 1990, and December 31, 1994, are the offspring of women who previously reported their diet during, or shortly before or after, their pregnancy with this child as part of the ongoing Nurses’ Health Study II. In 2006, the offspring reported physician-diagnosed food allergy. Mothers were asked to confirm the diagnosis and to provide available medical records and allergy test results. Two board-certified pediatricians, including a board-certified allergist/immunologist, independently reviewed each potential case and assigned a confirmation code (eg, likely food allergy) to each case. Unadjusted and multivariable logistic regression analyses were used to evaluate associations between peripregnancy consumption of P/TN by mothers and incident P/TN allergy in their offspring.

EXPOSURE

Peripregnancy consumption of P/TN.

MAIN OUTCOMES AND MEASURES

Physician-diagnosed P/TN allergy in offspring.

RESULTS

Among 8205 children, we identified 308 cases of food allergy (any food), including 140 cases of P/TN allergy. The incidence of P/TN allergy in the offspring was significantly lower among children of the 8059 nonallergic mothers who consumed more P/TN in their peripregnancy diet (≥5 times vs <1 time per month: odds ratio = 0.31; 95% CI, 0.13-0.75; Ptrend = .004). By contrast, a nonsignificant positive association was observed between maternal peripregnancy P/TN consumption and risk of P/TN allergy in the offspring of 146 P/TN-allergic mothers (Ptrend = .12). The interaction between maternal peripregnancy P/TN consumption and maternal P/TN allergy status was statistically significant (Pinteraction = .004).

CONCLUSIONS AND RELEVANCE

Among mothers without P/TN allergy, higher peripregnancy consumption of P/TN was associated with lower risk of P/TN allergy in their offspring. Our study supports the hypothesis that early allergen exposure increases tolerance and lowers risk of childhood food allergy.

JAMA Pediatrics
Prospective Study of Peripregnancy Consumption of Peanuts or Tree Nuts by Mothers and the Risk of Peanut or Tree Nut Allergy in Their Offspring

JAMA Pediatr 2014 Feb 01;168(2)156-162, AL Frazier, CA Camargo, S Malspeis, WC Willett, MC Young

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