Fish oil supplementation in the first six months of life helps reduce the production of allergy-related mediators and increase levels of omega 3 fatty acids in infants, recent research suggests.
A team of UWA researchers collected blood samples from 120 six-month-old infants who had been given either fish oil or control oil from birth and assessed fatty acid levels and immune cell responses to egg, milk and house dust mite allergens.
Compared to the control oil group, the fish oil group showed significantly higher levels of the two main beneficial omega-3 fatty acids present in fish oil, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and lower levels of the potentially inflammatory omega-6 fatty acid arachidonic acid (AA).
These subjects with higher levels of DHA also showed significantly lower interleukin 13 (IL-13, a mediator of allergic inflammation) responses to house dust mite allergens and lower interleukin 5 (IL-5, another allergic cytokine) responses to milk allergens.
UWA School of Paediatrics and Child Health researcher Nina D’Vaz says the reduction in IL-13 and IL-5 in the fish oil group, accompanied by higher levels of two cytokines that are not generally associated with allergies (tumor necrosis factor, TNF-α and interferon-gamma, IFN-γ) may indicate a favourable shift in immunity.
“Although modest, the reduction in the ‘bad’ allergic mediators IL-5 and IL-13 indicates that giving fish oil or elevating omega-3 fatty acid levels may influence the immune system in a way potentially favourable in terms of allergy development,” she says.
However, although omega-3 fatty acids are generally considered anti-inflammatory and omega-6 fatty acids considered pro-inflammatory, a good balance between the two fatty acids is important, Dr D’Vaz says.
“It is not as clear cut as saying, ‘Omega-3 is good and omega-6 is bad’; they are both essential fatty acids,” she says.
“With recent changes to Western diets there is now a balance heavily in favour of omega-6s from vegetable oils and highly processed foods which may be of importance in the ongoing rise in allergy prevalence.
“The theory behind fish oil supplementation is finding a good balance between the fatty acids."
Dr D’Vaz says the UWA team’s follow-up study, due for publication in coming months, will clarify whether the immunomodulatory effects of fish oil and omega-3 fatty acids observed in this study translate to an effect on actual allergies.