Reports of food allergies have nearly doubled among black children during the past two decades, a new study reveals, and health professionals aren't sure why. Childhood food allergies are rising across races, but the spike among black children is alarming, according to researchers from Johns Hopkins University in Baltimore. It's unclear if the increase is because of better detection, environmental triggers or some other cause.
Reports of food allergies have nearly doubled among black children during the past two decades, a new study reveals, and health professionals aren’t sure why.
Childhood food allergies are rising across races, but the spike among black children is alarming, according to researchers from Johns Hopkins University in Baltimore. It’s unclear if the increase is because of better detection, environmental triggers or some other cause.
“It definitely leaves us with a number of questions,” said Corinne Keet, lead study author and an assistant professor of pediatrics at Johns Hopkins.
The researchers found that, between 1988 and 2011, food allergies among black children increased 2.1 percent every 10 years. Food allergies increased 1.2 percent among Latino children during the same period and 1 percent among white children. The analysis involved more than 395,000 children.
Black children generally have higher levels of IgE, an antibody the immune system creates more of when someone has an allergy, Keet said. But only recently have they reported food allergies more frequently than white children.
The allergies were self-reported by parents. The children did not receive a diagnosis from an allergist, which leaves significant room for error, Keet said.
“Food intolerance can often be mistaken for allergy because not all symptoms associated with foods are caused by food allergy,” she said.
An allergic reaction is a response by the immune system, while intolerance is a problem during digestion. Food intolerance might be uncomfortable, but it doesn’t have the potential to be life-threatening, as a food allergy does.
Keet is planning a follow-up study using blood samples. But a Columbus allergist said self-reported data, though far from perfect, are probably more-accurate than blood testing.
“If you ask someone, ‘What happens when you eat the food?’ and they say, ‘I have a reaction,’ that is more accurate to me than if I did a lab test,” said Dr. Irene Mikhail, an allergist at Nationwide Children’s Hospital.
Mikhail said a lot of people test positive for food allergies but never experience symptoms.
The best way to diagnose an allergy is through a clinical “food challenge,” she said. That’s when an allergist exposes a patient to different foods and watches what happens.
But conducting a sizable study using food challenges would be, well, challenging.
“There are some ethical concerns with doing that, and you’re going to be subjecting some kids to a bad reaction,” Mikhail said. “So let’s go based on the next best thing, and that is asking people.”
A 2012 study found similar racial trends for food allergies. It also found that socioeconomic factors might play a par, regardless of race. Greater rates of peanut allergies, for example, were found in families with higher economic status, which supports the “hygiene hypothesis” of many allergists.
The theory says a lack of early-childhood exposure to germs increases the likelihood of allergic diseases, said Dr. Nabeel Farooqui, an allergist at Ohio State University’s Wexner Medical Center. Over-sanitization might suppress the immune system’s development.
Another theory is that people are being exposed to antibiotics too often, which is altering the immune system, he said.
Farooqui, who sees patients of all ages and races, said he hasn’t noticed any racial trends when diagnosing food allergies. He did say, however, that food allergies are growing more prevalent among all groups.
“The question that really needs to be answered is: Are we recognizing it more in this group of people,” Mikhail said, “or is it that there really is truly a more-rapid increase in this group of people?”