A new study from Northwestern University Medicine shows at least 4.5 million adults suffer from peanut allergies with one in six developing a serious allergy after turning 18.; "This was actually really surprising for us that adults are developing more food allergies," said Dr. Ruchi Gupta/Professor of Pediatrics, Northwestern University Feinberg School of Medicine. Study author Dr. Gupta says it could have to do with microorganisms that make up the microbiome of the gut as well as infections that alter the immune system and hormonal changes. "The why is the biggest question that all of us researchers across the world are asking. And we do not have a clear answer. How do we better understand this? How do we help adults with a food allergy?" Dr. Gupta said.