THE DETAILS: Researchers looked at the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey data for just over 8,000 people ages 2 to 85 who’d had their blood levels of folate and immunoglobulin E (IgE, antibodies that fight allergic reactions) measured. They focused specifically on allergies to dogs, cats, cockroaches, dust mites, and a type of mold associated with severe asthma, as well as any diagnoses of wheezing or asthma. Regardless of age, people whose folate levels fell on the higher end of normal had significantly lower IgE levels, and for every 1-unit increase in folate levels, the researchers saw a 50 percent decrease in a person’s chances of having allergic reactions to those allergens. They found some reduction in the odds of having asthma and wheezing among people with high folate levels, but the association wasn’t as strong as with day-to-day allergies.
They also found that African Americans had lower levels of serum folate levels, and that’s a group with high rates of asthma. “There’s always been a marked disparity among asthma in inner-city minority kids, particularly African Americans,” says lead author Elizabeth Matsui, MD, MHS, associate professor of pediatrics at Johns Hopkins Children’s Center. “Lower serum folate levels could be contributing to more severe cases of the disease,” she notes.
WHAT IT MEANS: Keep your folate levels healthy. But don’t go popping folic acid supplements just yet, Dr. Matsui says. “A majority of people in U.S.—upwards of 98 percent—are not folate deficient, and there’s some controversy about whether or not high serum folate levels can actually make allergies and asthma worse,” she says. She points to another study on mice, which found that mouse mothers who were given folate while pregnant had babies that developed allergic lung diseases. “The timing of the folic acid exposure may impact what the relationship is between folate and the risk of allergies and asthma,” she says, cautioning that pregnant mothers should continue to take folic acid because of its proven protection against neural tube defects.
What this study does show is that people whose folate levels fall within the high range of normal are less likely to have allergies, wheezing, and asthma, says Dr. Matsui. Based on the findings, she says, folate also may protect against allergens beyond the ones they tested, including pollen, ragweed, and other seasonal allergy triggers that make us miserable.
Your best protection: Eat a healthy diet of folate-rich foods to keep your levels high without overdoing it.
According to the USDA’s Nutrient Database, some of the most folate-rich foods include:
• Long-grain white rice
• White or all-purpose wheat flour
• Lentils, black-eyed peas (also called “cowpeas”), pinto beans, and chickpeas
• Orange juice
Check the Rodale Recipe Finder for suggestions on preparing these foods. Orange juice and fortified breakfast cereals are also good sources.