By Peter Galvin, MD

Pellagra, a nutritional disease caused by vitamin B3 (niacin) deficiency, was one of the most pressing public health issues of the early 20th century in the U.S., especially in southern agricultural areas that were plagued by poverty and racism. It was also common in incarcerated and medically institutionalized people. Black people in the U.S. were disproportionally affected. It can still be seen among patients with limited diets (those with severe alcohol use disorder) or those with malabsorption. Pellagra manifests clinically as dermatitis (skin rash) – dermal plaques with hyperpigmentation, erythema (redness), and a shellac-like desquamation (skin loss) known as “Casal necklace” (affects the face and lower neck) – along with diarrhea and, in severe cases, dementia and death (the “4 D’s”).

Niacin, also known as nicotinic acid, is derived from the amino acid tryptophan. Humans and other mammals cannot synthesize tryptophan and so must obtain it from dietary sources. Tryptophan is necessary for the biosynthesis of some proteins and is the precursor of the neurotransmitter serotonin, melatonin, and, of course, vitamin B3. Niacin is added to fortified packaged foods like flour and can be found naturally in meat, poultry, and red fish (tuna and salmon). It is also found, albeit in lesser amounts, in nuts, seeds, and legumes. For those of you who share my passion for astronomy, a tryptophan emission spectrum was found last year in the interstellar gas cloud of the star cluster IC 348.

In the late nineteenth and early twentieth centuries pellagra was thought to be an infectious disease. Dr. Joseph Goldberger (1874-1929), a U.S. Public Health Service officer, spent much of his later career investigating the origins and treatment of pellagra. He conducted clinical investigations at Rankin Prison Farm in Mississippi, where he oversaw the feeding of a restricted diet to nutritionally intact prisoners to observe the effects of the prison diet on the emergence of signs of pellagra. He did similar work at Central State Hospital in Georgia and Spartanburg Pellagra Hospital in South Carolina where he oversaw the feeding of a balanced diet to patients to investigate foods that contained the “pellagra preventative factor,” later identified as niacin by Dr. Conrad Elvehjem at the University of Wisconsin. Goldberger ultimately demonstrated that pellagra was a nutritional rather than an infectious illness, and he implicated poverty in the Southern U.S. as a cause.

Goldberger believed that physicians needed additional training to recognize the subtle rash and other signs of pellagra, so he first tried photographing patients with the illness. But unfortunately, he found black and white photos provided “less than satisfactory results,” so in 1919 he commissioned the portrait artist John Wesley Carroll (1892-1959) to paint color portraits of the patients. Carroll was well known to the government as he had been commissioned to paint pictures of WWI battle injuries. Carroll painted 41 portraits which were lost until being found at the National Institute of Health (NIH) in the 1950s. While Carroll’s WWI work was lost, his portraits survive. He should be commended for spending hundreds of hours with these patients who were suffering from a disease that, at the time, was thought to be contagious.

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