New Risk Factor for Allergies in Children Discovered: Unsaturated Fatty Acids

"In the same way that maturation of the immune system is hampered if we live too purely, it can probably be impaired if the immune system is hampered by a high blood concentration of unsaturated fat," says Agnes Wold, who is an immunologist at Sahlgrenska Academy at the University of Gothenburg. She is one of the researchers behind the study.

"We already know that unsaturated fatty acids hamper activation of the immune system. This is probably beneficial for an elderly person suffering from inflammation. The immune system of an infant, however, needs a kick start for the system to mature properly," she says.

Researchers examined the composition of fat in the umbilical cord blood from 129 newborns. The children were selected from a cohort of 794 children born in Östersund 1996-1997. Their cord blood was frozen, and the children were monitored with regular allergy check-ups until the age of 13.

Of the selected children, 48 showed no signs of allergies during their childhood, while 44 had respiratory allergies (asthma and/or hay fever) and 37 had atopic eczema at age 13.

When the fatty acid pattern was examined in the three groups, it was discovered that the children who suffered from allergies at age 13 had a higher blood concentration of polyunsaturated fat at birth than the children who had not developed any allergies did. Both a high percentage of omega 3 fatty acids and a high percentage of omega 6 fatty acids were shown to be risk factors for developing allergies. The newborns who remained free of allergies during their childhood thus had a higher percentage of monounsaturated fat in their cord blood. The results remained valid even if the presence or non-presence of allergies in the children's mothers was taken into account.

The results are controversial since women are currently encouraged to eat less saturated fat, and food for infants is often enriched with omega 3 fatty acids. One conclusion that has been drawn, primarily from studies on cardiovascular disease in middle-aged individuals, is that unsaturated fat is beneficial.

Several studies have also shown that children develop fewer allergies if they eat fish from an early age. This has been interpreted as support for the idea that unsaturated fatty acids are good for infants since fish is rich in unsaturated omega 3 fatty acids.

"Fish contains so much more than just omega 3 fatty acids. You cannot draw the conclusion from our study that pregnant women and small children should not eat fish," says Ann-Sofie Sandberg, nutrition researcher and professor of food science at Chalmers. She is one of the researchers behind the study. Just the opposite is true since we know that small children develop fewer allergies if they eat fish from an early age," she says.

Senior Physician Anna Sandin, paediatrician and allergy researcher, personally monitored all of the children born during the course of one year (1996-1997) at Östersund Hospital in Jämtland until the age of 13:

"It is fantastic that all of the blood specimens I saved were of use during this collaboration initiative. Now I am planning to start a new cohort – this time it will consist of all of the children born at Sunderby Hospital in Norrbotten during the course of one year," she says. "I can monitor them until I retire; there is still so much we don't know in terms of why allergies develop so frequently today." -- Chalmers