Researchers from Johns Hopkins Children’s Center report for the first time in humans a link between blood levels of folate, with the findings published online ahead of print in the Journal of Allergy & Clinical Immunology.
“Our findings are a clear indication that folic acid may indeed help regulate immune response to allergens, and may reduce allergy and asthma symptoms,” said lead researcher Elizabeth Matsui.
“But we still need to figure out the exact mechanism behind it, and to do so we need studies that follow people receiving treatment with folic acid, before we even consider supplementation with folic acid to treat or prevent allergies and asthma,” she added.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn.
Matsui and her co-workers reviewed the medical records of over 8,000 people aged between 2 and 85. Data was collected on blood levels of folate and respiratory and allergic symptoms, as well as on levels of immunoglobulin E (IgE), the predominant antibody associated with an allergic response.
Folate is found in foods such as green leafy vegetables, chick peas and lentils. Folic acid - the synthetic, bioavailable form of folate – is obtained from grain products in the US and Canada following introduction of mandatory fortification in 1998.
According to the findings of the study, higher folate levels were associated with lower levels of IgE antibodies, as well as fewer reported allergies, less wheezing and lower likelihood of asthma.
Specifically, the lowest average folate levels, defined as less than 8 nanograms per millilitre (ng/mL) were associated with a 40 per cent increase in the risk of wheezing, compared to the highest folate levels, defined as more than 18 ng/ml.
Moreover, the lowest folate levels were linked to a 30 per cent higher risk of elevated IgE antibody levels, compared to the highest folate levels.
The researchers also report that people with the lowest folate levels had a 31 per cent higher risk of allergic symptoms, and a 16 per cent higher risk of having asthma, compared to those with the highest folate levels.
The area of study is ongoing, confirmed the researchers, with the plan to conduct a placebo-controlled trial of folic acid placebo in people with allergies and asthma.
The research was funded by the National Institutes of Health.
Folic acid and NTDs
Currently, supplementation with folate and folic acid is recommended to all women of child-bearing age since most neural tube defects (NTDs), including spina bifida and anencephaly, occur within the first 22 to 28 days of pregnancy, when the mother-to-be is not aware she is even pregnant.
Folic acid supplements after this time are too late to prevent neural tube defects and therefore fail to benefit women with unplanned pregnancies - more than half of all pregnancies in the US.
Preliminary evidence indicates that the 1998 introduction of public health measures in the US and Canada to mandatory fortify grain products has reduced the incidence of NTDs by 15 to 50 per cent.