Folic acid, or vitamin B9, essential for red blood cell health and long known to reduce the risk of spinal birth defects, may also suppress allergic reactions and lessen the severity of allergy and asthma symptoms, according to new research from the Johns Hopkins Children’s Center.
In what is believed to be the first study in humans examining the link between blood levels of folate – the naturally occurring form of folic acid — and allergies, the Hopkins scientists say results add to mounting evidence that folate can help regulate inflammation.
Recent studies, including research from Hopkins, have found a link between folate levels and inflammation-mediated diseases, including heart disease. A report on the Hopkins Children’s findings appears online ahead of print in the Journal of Allergy & Clinical Immunology.
Cautioning that it’s far too soon to recommend folic acid supplements to prevent or treat people with asthma and allergies, the researchers emphasize that more research needs to be done to confirm their results, and to establish safe doses and risks.
Reviewing the medical records of more than 8,000 people ages 2 to 85 the investigators tracked the effect of folate levels on respiratory and allergic symptoms and on levels of IgE antibodies, immune system markers that rise in response to an allergen. People with higher blood levels of folate had fewer IgE antibodies, fewer reported allergies, less wheezing and lower likelihood of asthma, researchers report.
“Our findings are a clear indication that folic acid may indeed help regulate immune response to allergens, and may reduce allergy and asthma symptoms,” says lead investigator Elizabeth Matsui, M.D. M.H.S., pediatric allergist at Hopkins Children’s. “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.”
The current recommendation for daily dietary intake of folic acid is 400 micrograms for healthy men and non-pregnant women. Many cereals and grain products are already fortified with folate, and folate is found naturally in green, leafy vegetables, beans and nuts.
Other findings of the study:
Blacks and Hispanics had lower blood folate levels — 12 and 12.5 nanograms per milliliter, respectively — than whites (15 ng/ml), but the differences were not due to income and socio-economic status.
The Hopkins team is planning a study comparing the effects of folic acid and placebo in people with allergies and asthma.
Asthma affects more than 7 percent of adults and children in the United States, and is the most common chronic condition among children, according to the Centers for Disease Control and Prevention. Environmental allergies are estimated to affect 25 million Americans, according to the CDC.
The research was funded by the National Institutes of Health.
BACKGROUND: Folic acid is known to be associated with inflammatory diseases, but the relationship between folic acid and allergic diseases is unclear. OBJECTIVES: The purpose of the study was to examine the relationship between serum folate levels and markers of atopy, wheeze, and asthma. METHODS: Data were obtained from the 2005-2006 National Health and Nutrition Examination Survey in which serum folate and total IgE levels were measured in 8083 subjects 2 years of age and older. A high total IgE level was defined as greater than 100 kU/L. Allergen-specific IgE levels were measured for a panel of 5 common aeroallergens. Atopy was defined as at least 1 positive allergen-specific IgE level. Doctor-diagnosed asthma and wheeze in the previous 12 months were assessed by means of questionnaire. RESULTS: Serum folate levels were inversely associated with total IgE levels (P < .001). The odds of a high total IgE level, atopy, and wheeze decreased across quintiles of serum folate levels, indicating a dose-response relationship between serum folate levels and these outcomes. Each of these associations remained statistically significant after adjusting for age, sex, race/ethnicity, and poverty index ratio. Adjusted odds ratios associated with the fifth quintile of folate relative to the first quintile were as follows: high IgE level, 0.70 (95% CI, 0.53-0.92); atopy, 0.69 (95% CI, 0.57-0.85); and wheeze, 0.60 (95% CI, 0.44-0.82). Higher folate levels were also associated with a lower risk of doctor-diagnosed asthma, but this finding was not statistically significant (odds ratio for fifth quintile vs first quintile, 0.84 [95% CI, 0.70-1.02]). CONCLUSIONS: Serum folate levels are inversely associated with high total IgE levels, atopy, and wheeze.
Matsui EC, Matsui W. Higher serum folate levels are associated with a lower risk of atopy and wheeze. J Allergy Clin Immunol. 2009 Apr 29. [Epub ahead of print]
Source: Johns Hopkins Medicine Released: Mon 27-Apr-2009,