Pellagra: Niacin Deficiency, Its History, Causes and Treatment

What pellagra looks like

MedlinePlus lists these symptoms: delusions or mental confusion, diarrhea, weakness, loss of appetite, abdominal pain, inflamed mucous membranes, and scaly skin sores, especially in sun-exposed areas. [1]

You may see the "three Ds" (dermatitis, diarrhea, dementia). A 2012 case series and review notes that pellagra seldom shows all three, and that it can appear as delirium alone. [2] Many conditions cause these symptoms, so symptoms alone cannot show that someone has pellagra. See Vitamin deficiency symptoms: what they can and cannot tell you.

History: corn, poverty and a missing vitamin

A historical review in a neurology handbook reports that pellagra was unknown in Europe before maize arrived from the New World. It was linked in the 18th century with poverty and diets based on corn. [3] The same review says it became epidemic among poor Southerners in the United States in the early 20th century, partly because of monotonous diets and new milling methods that removed vitamins from grain. [3]

The review credits Joseph Goldberger, between 1914 and 1929, with studies that supported a dietary explanation over the then-popular toxic and infectious theories. Niacin was identified as the preventive factor in 1937, and the review says vitamin fortification of foods during World War II ultimately eradicated endemic pellagra in the United States. [3]

Why corn? MedlinePlus explains that corn is a poor source of tryptophan and that its niacin is tightly bound to other grain components. Soaking corn in limewater releases the niacin, a method used to cook tortillas in Central America where pellagra is rare. [1] A scoping review of South Africa from 1897 to 2019 also tied pellagra to poverty and over-dependence on maize as a staple food. [4]

Modern causes

Today, pellagra in high-income countries is usually linked to health or social circumstances rather than to corn. MedlinePlus lists gastrointestinal diseases, weight loss (bariatric) surgery, anorexia, excessive alcohol use, carcinoid syndrome and certain medicines among the causes. [1] A case series describes pellagra in people with chronic alcohol use, homelessness or AIDS, and notes it can be mistaken for alcohol withdrawal delirium. [2]

Diagnosis and treatment are for clinicians

MedlinePlus says a provider will do a physical exam and ask about your diet; urine tests to check niacin and blood tests may be done. [1] Treatment uses prescribed niacin supplements, sometimes other supplements, and treatment of the underlying condition. MedlinePlus says to follow the provider's instructions exactly on how much and how often. [1] People often do well after treatment. [1] This page gives no amounts.

Prevention, according to MedlinePlus, is a well-balanced diet and treatment of health problems that cause pellagra. [1] The NHS notes niacin cannot be stored in the body, so it is needed in the diet every day. [5] See Niacin (vitamin B3) for food sources and official intake levels.