Pellagra

Pellagra, generally caused by vitamin niacin (Vitamin B3) deficiency, is next in my series of nutritional deficiency diseases, and is one with an interesting history. It is quite rare today except in areas of famine where corn is the primary source of calories.  The name pellagra is felt to have come from Northern Italy where it the disease was prevalent in areas where maise was a dominant food crop.  It was known there at pelle (skin)  agra (sour).   Pellagra was unknown in the Native American population despite a diet very dependent on maize.  It turns out that they soaked their corn in lime, an alkali as their standard method of preparation, and this made niacin that was bound in the corn nutritionally available.  (1) As maize was exported to other cultures this method of preparation was not followed, and niacin deficiency became prevalent.

In the early 1900’s in the US south pellagra was epidemic.  The Yale Journal of Biology and Medicine has a very interesting article on the history of pellagra in the US, and comments on some of the lessons we could learn from today in political and social bias that led to erroneous conclusions about the cause.  Pellagra was occurring in poor southern sharecroppers, and was felt likely to be due to poor hygiene or other socioeconomic factors.  The cause came to be understood by some classic experiments after in 1914 the U.S. Public Health Service set up the Spartanburg Pellagra Hospital in Spartanburg, South Carolina.   There a primary researcher Joseph Goldberger performed several experiments on prisoners that documented that pellagra was some sort of nutritional deficiency, although he made no further progress in identifying the missing nutrient.  In one experiment he took prisoners who were healthy eating a balanced diet, fed them corn only, and within a week they began to have became ill, and within 3 weeks 7 of the 11 developed pellagra.  This resolved with feeding them fruit and vegetables. He later also found that brewer’s yeast prevented pellagra.

By the mid to late 1930’s after initially finding niacin cured pellagra (black tongue) in dogs, it was discovered that niacin deficiency was the cause of pellagra in humans.  Pellagra is produced in the body by using the amino acid tryptophan as a building block, so a diet deficient in tryptophan can also lead to pellagra.  In the early 1940’s vitamin fortification of the food supply became widespread in the U.S. and since then pellagra has essentially disappeared as a nutritional deficiency.

Pellagra was known as the 4-D’s disorder, with clinical manifestations of dermatitis, dementia, diarrhea and death.  The skin manifestations were the most obvious to the observer.  In the 1700’s in Austria it was known as Asturian Leprosy because the skin manifestations are so dramatic.