COPENHAGEN, DENMARK. Infants are born with an immature immune system. Important characteristics of the immature immune system are an inadequate ability to produce certain cytokines (hormones that activate the immune system), notably gamma-interferon and interleukin-2 (IL-2) and a preponderance of Th2 helper T-cells over Th1 helper cells. Th1 helper T-cells enhance the ability of the immune system to respond to virus, bacteria, fungi and parasites, while Th2 helper T-cells are involved in allergic reactions and, if overactive, can cause inflammation such as seen in rheumatoid arthritis. Th2 cells release interleukin-6 (IL-6), excessive amounts of which are associated with allergic reactions and autoimmune disorders such as wheezing and asthma.
Healthy maturation of the infant’s immune system would thus involve increased production of gamma-interferon and/or IL-2 and an increase in Th1 cells to improve the ratio of Th1 to Th2 cells. Researchers at Copenhagen University report that supplementation with fish oil at age 9 months helps accelerate maturation.
Their study involved 64 healthy Danish infants who were fed either formula or cows’ milk for a 3-month period following cessation of breast-feeding. Half the children were also given a teaspoon (5 mL) of fish oil daily providing 571 mg/day of eicosapentaenoic acid (EPA) and 381 mg/day of docosahexaenoic acid (DHA). The infants had blood samples drawn at the beginning and end of the trial. Analyses of red blood cells showed a 450% increase in EPA and a 40% increase in DHA among infants who had supplemented with fish oil; these increases were accompanied by decreases in linoleic acid and arachidonic acid of 15%.
Whole blood samples were cultured and stimulated with various agents to provoke an immune response. The researchers noted a substantial increase in the production of gamma-interferon and a reduced production of interleukin-10 (IL-10) in the infants supplemented with fish oils. A reduced IL-10 production would indicate a dampened Th2 response to immune system provocation. Fish oil supplementation did not affect other markers of innate immunity or general inflammation (C-reactive protein and immunoglobulin E). The researchers conclude that daily fish oil supplementation between the ages of 9 and 12 months accelerates the maturation of infants’ immune systems and may be helpful in avoiding the development of allergic disorders.
Damsgaard, CT, et al. Fish oil supplementation modulates immune function in healthy infants. Journal of Nutrition, Vol. 137, April 2007, pp. 1031-36