Ways to Die: Pellagra
Pellagra (formerly “Asturian leprosy”) is one of the five pandemic deficiency diseases that have occurred in humans, and is caused by a lack of available niacin (vitamin B3) in the diet. Since niacin is a precursor to the NAD+/NADH molecules, which provide cellular energy throughout the body, many systems become disordered. Primary symptoms include weakness, insomnia, diarrhea, constant headache, sensitivity to sunlight (causing photo-dermatitis when exposed, as shown here on the face and hands), aggression, and eventually dementia. Death often follows within 4-5 years, if untreated.
One of the historical causes of pellagra was the widespread cultivation of corn, and the eventual usage of corn as a staple food, especially among the poor. While the corn plant does have niacin, it’s chemically bound and indigestible. The traditional Mesoamerican preparation of corn (now known as nixtamalization) by soaking it in limewater exposes the compound to a high pH (11+), which unbinds the niacin, and the human body is then able to absorb it. This practice is known to go back thousands of years, and is the reason that despite a maize-based diet, Native American peoples did not regularly suffer from pellagra.
Unfortunately, Europeans never really understood why the limewater was needed - indeed, we didn’t even understand what pellagra actually was until the 1930s. Up to that point, pellagra was known to be endemic to areas that were highly dependent upon corn, but it was believed to be either a germ or a maize-based toxin. It wasn’t until 1937 that Conrad Elvehjem identified the molecule in fresh meat and yeast called niacin, and its direct link to the condition was established.
Today, pellagra is very rare in the majority of the developed world, surfacing primarily in patients with chronic alcoholism or eating disorders. We now know that nuts, leafy greens, and whole-grain products also provide sufficient amounts of niacin, and the human body does not necessarily require meat or yeast as a source. However, in displaced populations requiring food aid, availability of niacin-providing nutriment is extremely limited, as many countries that provide aid still provide only oil and a basic cornmeal substance for food. Because of several outbreaks of pellagra and other deficiency diseases in refugee camps in the 1970s and 1980s, the United States and Western European food aid programmes now prepare their cornmeal with vitamin and mineral sprays to provide the necessary nutrients.
Want to know more? Read on:
The Mastery of Pellagra (1916 account of the ongoing pellagra epidemic)
How Vitamin B3 Works
Conrad Elvehjem: Further Studies on the Concentration of the Antipellagra Factor
Politics and Pellagra: The epidemic of pellagra in the U.S. in the early 20th century.
[Image Source: Tropical Diseases. Sir Patrick Manson, 1914]