Could Eating Certain Foods Reduce Your Risk of Asthma?
By LIDA TUNESI
Researchers have never completely understood what causes asthma, the disease that narrows airways and can impede breathing. Recently, Professor Mary Schooling of The Graduate School of Public Health & Health Policy found a connection between asthma and linoleic acid, giving new insight into this respiratory condition.
The paper, also authored by a colleague from The University of Hong Kong, appears in The American Journal of Clinical Nutrition.
These days, many researchers think of asthma as an autoimmune disease, meaning the symptoms arise when a person’s immune system overreacts to certain triggers such as pollen or cold air. Linoleic acid, a polyunsaturated fatty acid found in vegetable oils, is thought to lower immune responses, so the researchers wondered if there might be a connection between the two.
Along with vegetable oils, major sources of linoleic acid include nuts, eggs, meats and seeds, according to the U.S. National Library of Medicine.
Using genetic analysis methods, the researchers predicted people’s dietary intake of linoleic acid and looked for a relationship to asthma—mostly in people of white, European descent. They found that higher predicted levels of linoleic acid corresponded to a lower risk of asthma. The researchers also discovered that higher linoleic acid levels corresponded to lower counts of certain types of white blood cells, which play a part in our immune systems.
This supports the theory that the fatty acid may affect immune responses via these cells.
Scientists should examine the exact mechanism of this effect before recommending dietary changes, the authors caution. However, the results make sense from an evolutionary biology perspective. Evolutionary biologists think that the more energy an individual puts into reproduction, the less they can put into supporting their immunity. Linoleic acid is associated with fertility, the authors say, which would explain why it can lower immune responses and result in a lower risk of asthma.
Schooling explored a similar evolutionary idea in another study, using similar genetic methods to study the connection between reproduction and longevity in terms of cardiovascular health.