Omega-3 supplementation during pregnancy reduces infant risks for food allergy

Key takeaways:

• Maternal omega-3 supplementation had significant effects on egg and peanut sensitization among infants.
• Supplementation among infants did not have a significant effect on their food allergy status.

Maternal omega-3 supplementation contributed to decreases in risks for food allergy among infants, including egg and peanut sensitization, according to a review published in The Journal of Allergy and Clinical Immunology: In Practice.

However, omega-3 supplementation during infancy did not decrease these risks, Linh Ba Phuong Huynh, MD, MSc, School of Nutrition and Health Sciences, Taipei Medical University, Taiwan, and colleagues wrote.

The meta-analysis examined 12 randomized controlled trials published between 2003 and 2018 involving 3,274 mother-infant pairs, with mean doses of omega-3 polyunsaturated fatty acid (PUFA) ranging from 492 mg to 3,700 mg per day for mothers and 184 mg to 390 mg per day for infants.

Maternal omega-3 PUFA consumption while they were pregnant and lactating had significant effects on risks for egg sensitization (RR = 0.58; 95% CI, 0.47-0.73) and peanut sensitization (RR = 0.62; 95% CI, 0.47-0.8), the researchers found, but infant consumption did not have any protective effect on food allergy.

Specifically, the researchers said, the effects that maternal omega-3 supplementation had on the first 3 years of their child’s life (the “early period”) and afterward (the “late period”) were remarkably different.

There was a significant association between maternal omega-3 supplementation during pregnancy and lactation and food allergy (RR = 0.53; 95% CI, 0.33-0.85) during the early period but not during the late period, the researchers said.

Also, the researchers said, the protective effect that maternal omega-3 PUFA intake had on egg sensitization was inconsistent between the two periods, but it was consistent for peanut sensitization. Whereas maternal omega-3 supplementation reduced risks for egg sensitization only for the early period (RR = 0.55; 95% CI, 0.44-0.71), it reduced risks for peanut sensitization for the early (RR = 0.61; 95% CI, 0.4-0.94) and the late period (RR = 0.62; 95% CI, 0.44-0.87).

The five studies (n = 1,072) analyzing cow’s milk only found sensitization with omega-3 supplementation during pregnancy and lactation during the early period, with no differences in the numbers of infants reporting any event between the omega-3 PUFA and comparison groups.

Three studies (n = 1,412) found reductions in risk for cashew nut sensitization (RR = 0.45; 95% CI, 0.26-0.77; I² = 0%) during the late period with maternal omega-3 supplementation.

Additionally, three studies (n = 1,412) found no significant effect on food allergy status (RR = 0.93; 95% CI, 0.63-1.37; I² = 0%), egg sensitization (RR = 0.9; 95% CI, 0.65-1.27; I² = 0%) or peanut sensitization (RR = 0.95; 95% CI, 0.58-1.56; I² = 0%) with omega-3 PUFA supplementation in infants.

Further analysis found a log-linear dose-response relationship between the daily dose of omega-3 supplementation during pregnancy and incidence of infant egg sensitization during the early period (estimate = –0.0003; standard error = 0.0001; P < .001) with no heterogeneity across the studies (I² = 0%; Q = 3.34).

With an association between higher doses and lower incidence rates, the researchers said, there was a 3.2% decrease in risk for egg sensitization with every 100 mg per day of standard supplementation during the early period.

Based on these findings, the researchers said that maternal omega-3 supplementation contributes to decreases in risks for infant food allergy, but supplementation directly to infants does not.

The researchers called for additional studies investigating doses and durations of maternal omega-3 PUFA interventions as well as randomized controlled trials exploring the effects of infant supplementation, in addition to studies of how allergic skin inflammation, the gut microbiome and the timing of other food introductions may influence these results.