To eliminate lingering doubts that pellagra might be an infectious disease, Dr. Davis says, still another study was launched involving convicts. The prisoners, and the experimenters themselves, were injected with blood from people with pellagra or were exposed to their nasal or throat excretions. When the subjects didn't come down with the disease, researchers realized that pellagra could not possibly be infectious. Although researchers soon figured that poor diet was causing pellagra, it wasn't until 1937 that researchers pinpointed the exact source of the problem. Corn not only contains a form of niacin , a B vitamin, that the body cannot easily use but also can create an amino acid imbalance, says Dr. Davis.
Amino acids are the building blocks of protein , the stuff of which the body is made.
Eating corn as part of a well-balanced diet is not a problem, but a diet that consists almost exclusively of corn and corn products is devastating. As a result, pellagra is now rare. A few people still get pellagra, however, for reasons that have nothing to do with eating corn. Alcoholics and individuals with severe gastrointestinal problems often have difficulty getting enough niacin . Even then, diagnosing pellagra is not easy.