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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:
- People with the lowest folate levels (below 8 nanograms
per milliliter) had 40 percent higher risk of wheezing than people with
the highest folate levels (above 18 ng/ml).
- People with
the lowest folate levels had a 30 percent higher risk than those with
the highest folate levels of having elevated IgE antibodies, markers of
allergy predisposition.
- Those with the lowest folate
levels had 31 percent higher risk of atopy (allergic symptoms) than
people with the highest folate levels.
- Those with lowest folate levels had 16 percent higher risk of having asthma than people with the highest folate levels.
- 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.
Co-investigator on the study: William Matsui, M.D, of the Johns Hopkins Kimmel Cancer Center.
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