Giving a baby fish oil supplements may do little to prevent allergies, according to a new study.

Researchers found fish oil supplements had little impact on the risk of allergies by age 1 in babies who took them for the first six months of their lives.

Omega-3 fatty acids are necessary for health, but the body can´t make them. They must be gotten from foods or supplements.

Fish oil is a rich source of omega-3 fatty acids. Declining omega-3 fatty acid levels has been associated with a rise in allergies.

Other studies have suggested taking fish oil supplements during pregnancy can reduce the risk of allergies in infants.

This is the first study to look at the potential allergy-fighting benefits of fish oil supplementation in babies from birth to 6 months of age.

Another study in infants 6 months and older also found no effect.

“Our results, together with previous findings, will likely help define a ‘window of opportunity’ for allergy intervention using fish oil supplements,” write researcher Susan Prescott, PhD, MD, a professor at the University of Western Australia, and colleagues in the journal Pediatrics.

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The researchers looked at the effects of fish oil supplementation combining two kinds of omega-3s, DHA and EPA, vs. a placebo (olive oil) in 323 infants at high risk for allergies from birth to 6 months.

The results showed that at 6 months, DHA and EPA levels in the infants who took fish oil supplements were the higher than in the placebo group.

But overall, there was no effect on eczema, asthma, or food allergy risk by age 1.

"Fish oil supplementation during very early infancy was not effective in preventing allergic disease, which is consistent with the lack of significant effects of fish oil supplementation previously observed in late infancy,” write the researchers.

Researchers say these results suggest that the benefits of fish oil supplementation in preventing allergies are likely to occur earlier in infant development, as demonstrated by previous pregnancy fish oil supplementation studies.