During the first few decades of the twentieth century, a deficiency disease called pellagra, which is caused by lack of niacin (vitamin B3), sickened nearly 5 million Americans and caused perhaps 150,000 needless deaths. This disease had occurred sporadically wherever poor people depended too heavily on corn (maize) as a staple food—except in Mexico, for reasons I’ll explain below.
The Great Pellagra Epidemic in the United States broke out in earnest after the invention of the Beall degerminator in 1906. The epidemic worsened in 1921 because of the postwar collapse of cotton prices and peaked in the wake of catastrophic flooding in the Mississippi Valley in 1927, which forced nearly a million people from their homes. The epidemic persisted through the Dust Bowl of the early 1930s and then started to decline, partly because the decline in cotton prices encouraged farmers to grow more food instead of just cotton. The epidemic finally ended at the onset of World War II, partly because of rising incomes and partly because of the vitamin enrichment of processed grain products.
Corn has been grown in what is now Mexico for thousands of years. As the great Mexican poet Ramón López Velarde wrote, Patria: tu superficie es el maíz (my country, your surface is corn). The Mexican people have depended heavily on corn since the dawn of Mesoamerican civilization, yet pellagra is virtually unknown there. That’s because in Mexico, corn is traditionally treated by a process called nixtamalization. The corn kernels are soaked in an alkaline solution, made from calcium oxide or wood ashes. The alkaline solution helps to soften the corn kernels, making them easier to grind. It also helps make the corn more digestible and less susceptible to attack by molds and fungi. Plus, it makes the corn taste better.
Fortunately, you don’t have to go to all this trouble yourself. The masa harina that I use to make corn tortillas has already undergone nixtamalization. All I have to do is add water and plop a ball of dough on my electric tortilla press. Unfortunately, when the Spanish introduced corn to other parts of the world, they didn’t introduce the nixtamalization process with it. As a result, Europeans and others who started depending too heavily on corn as a staple food were prone to a disease called pellagra, which means “rough skin” in Italian.
The rough skin, or dermatitis, was only one of the “four D’s” of pellagra. The others were diarrhea, dementia, and death. At first, pellagra was mistakenly thought to be infectious. Then, when people noticed that it tended to occur in poor families and in prisoners and mental patients, it was mistakenly thought to be genetic. In the heyday of the eugenics movement during the 1920s, some eminent scientists denied the increasingly compelling evidence that pellagra was due to a nutrient deficiency, claiming instead that feeding poor people would only lead to an increase in pellagra, because it would enable “pellagrins” to have more children.
In the United States, pellagra occurred mainly in the South, among the desperately poor and among people confined to prisons or mental institutions. The disease resulted from a diet that consisted of little other than cornmeal flavored with a tiny bit of salt pork (not enough to provide enough niacin) and black molasses. This was the inspiration for the traditional blues song “Cornmeal, Meat, and Black Molasses.” People who could afford to include virtually anything else in their diet simply didn’t get pellagra. It’s interesting that the song is often sung as “Cornmeal, peas, and black molasses.” Peas are a good, cheap source of niacin and would have prevented pellagra.
Although cases of pellagra had been occurring in the United States for many years, the epidemic exploded after 1906, with the introduction of the Beall degerminator. This equipment for processing corn removed the oily “germ” or embryo from the rest of the corn kernel. The corn germ could then be used for making corn oil, and the remaining cornmeal was better able to resist spoilage. Unfortunately, this defatted cornmeal was also much lower in niacin than regular cornmeal. This removal of a source of niacin from an already deficient diet was a public health disaster.
The cure for pellagra was discovered by a courageous employee of the U.S. Public Health Service, Dr. Joseph Goldberger. To prove that pellagra was not contagious, he inoculated himself, his wife, and some volunteers from the Public Health Service with material from the skin lesions and nasal secretions of people with pellagra. They even went so far as to eat feces from people with pellagra. Yet nobody got pellagra as a result. Goldberger then recruited volunteers at a prison in Mississippi. In 1923, he reported that feeding the men nothing but cornmeal, fatback, and molasses caused pellagra, which was then cured by feeding the men other foods, such as peas, beans, collard greens, and wheat bread. By 1926, Goldberger proposed that yeast extract be used to prevent and treat pellagra. The precise nutrient that was responsible for curing pellagra was eventually identified in 1937.
Goldberger’s experiments provided compelling scientific evidence that pellagra was caused by a nutritional deficiency and could be cured by a healthy diet or by nutrient supplements. Yet many prominent members of the American scientific community refused to accept Goldberger’s conclusions. Unfortunately, the only way to end the pellagra epidemic was to increase the incomes of the poorest people in the United States—especially the sharecroppers and millworkers of the South—so that they could afford to eat a healthy diet. People who could afford to eat anything besides cornmeal flavored with molasses and a little bit of fatback generally did so, and thus avoided pellagra. Unfortunately, increasing the incomes of sharecroppers and millworkers meant lower profits for their employers.
During the catastrophic flooding of the Mississippi River in 1927, Goldberger advised the Red Cross to add yeast extract to the food rations that it was distributing to people who had been devastated by the flood. The yeast extract rapidly cured pellagra and prevented new cases. Unfortunately, it wasn’t available to everyone. Black men who went to a Red Cross camp for relief ran a serious risk of being taken from their families and forced to do unpaid labor at gunpoint.
After 1923, it was obvious to anyone not completely blinded by a racist, right-wing political agenda that pellagra was a result of vitamin deficiency, and that it could be prevented and cured by any reasonable diet. The development of yeast extracts as a multivitamin supplement made it possible to “enrich” grains (i.e., to add back the vitamins that had been stripped out of the grains by processing). After chemists isolated the individual vitamins and figured out how to make large quantities of them cheaply, enrichment of processed grain products became even cheaper and easier.
Although food enrichment proposals were fiercely resisted at first, the U.S. government started requiring enrichment of any food products that it was buying for military use. Thus, enrichment of grain products became just part of the price of admission for getting valuable contracts with Uncle Sam. As a result, enrichment of grain products became routine in the United States, and pellagra was virtually wiped out.
Today, pellagra is extremely rare in the United States. The rare cases that occur today are mainly in alcoholics, in people who have eating disorders or are following “fad” diets, and in people who can’t absorb enough vitamins from their food or who have trouble converting tryptophan to niacin. Pellagra is common in people with anorexia, and it may make the anorexia worse. The lack of niacin can end up triggering the release of hunger-suppressing hormones that make it easier for people to starve themselves.
Both pellagra and beriberi are B vitamin deficiency syndromes that result from people depending too heavily on a single, improperly processed grain as a staple food. Originally, both of these diseases were mistakenly believed to be the result of protein deficiency, because people who could afford to buy and eat animal-based foods didn’t get either disease. Yet it’s easy to get thiamine and niacin from plant sources. That’s because the plants themselves need those vitamins for their own metabolism, and they make their own supply. Plants also contain all of the essential amino acids. It’s virtually impossible to get a protein deficiency on any reasonable diet of whole plant foods.