What Was the Mortality Rate of Pellagra?

December 28, 2025 •

3 min read

During epidemics in the early 20th century, especially in the American South, the mortality rate of pellagra was high, with approximately 100,000 deaths recorded between 1906 and 1940. This niacin deficiency disease proved fatal for many, largely impacting vulnerable populations.

Quick Summary

Historically, untreated pellagra, a severe niacin deficiency, had a very high mortality rate, often resulting in death within five years, particularly during epidemics in the early 20th century.

Key Points

Devastating Historical Mortality: During its peak epidemic in the early 20th century, pellagra was responsible for approximately 100,000 deaths in the American South.
Fatal Without Intervention: Untreated pellagra often progressed to death within about five years, a grim reality during the major epidemics.
Cause Discovery was Key: Mortality rates plummeted after the discovery that pellagra was a niacin deficiency, enabling simple and effective treatment.
Food Fortification Eradicated Epidemics: The widespread practice of enriching staple foods with niacin effectively eliminated large-scale pellagra outbreaks in developed nations.
A Rare, Treatable Condition Today: In the modern era, due to improved nutrition, pellagra is rare and highly treatable, making death from the disease very uncommon.
Vulnerable Populations Remain at Risk: Despite its decline, pellagra still affects certain high-risk groups, such as chronic alcoholics, where mortality could still occur if untreated.

The Deadly History of Pellagra

Pellagra, a disease caused by a severe deficiency of niacin (vitamin B3), became a public health crisis in the United States during the early 20th century. It was especially rampant in the American South, affecting millions of people who relied on diets dominated by cornmeal, a grain low in absorbable niacin. The disease was characterized by the 'four Ds': dermatitis, diarrhea, dementia, and, if left untreated, death. For decades, its cause remained a medical mystery, and its devastating effects were misunderstood, often misattributed to poor hygiene or infectious agents.

Peak Mortality During the American Epidemic

The mortality rate of pellagra was notoriously high during the peak of its American epidemic, from around 1906 to 1940. During this period, an estimated 3 million people were afflicted, and over 100,000 died as a direct result of the disease. The disease particularly struck impoverished communities and people in institutions like orphanages and mental asylums, where monotonous and restricted diets were common.

Annual Fatalities: At the epidemic's peak around 1928, pellagra was reportedly killing about 7,000 people annually in the southern U.S..
Leading Cause of Death: In some areas of the South, pellagra became one of the leading causes of death, underscoring its public health significance before its cause was known.
Geographic Concentration: Due to dietary habits and poverty, the disease was overwhelmingly concentrated in the southern states.

The Link to Diet and Its Discovery

The high mortality rate was directly linked to the widespread lack of understanding regarding the disease's nutritional origin. Public health officials and the medical community were stumped until Dr. Joseph Goldberger of the U.S. Public Health Service demonstrated in the 1910s that pellagra was not contagious but rather a dietary deficiency. His groundbreaking work involved carefully controlled human studies, including feeding nutrient-poor diets to volunteers, and ultimately linking the disease to a lack of niacin.

Goldberger’s discovery, though initially met with skepticism, was the turning point. The eventual recognition of the disease's cause allowed for effective preventive measures and treatment to be developed. With simple niacin supplementation and improvements in diet, the disease could be cured, preventing the progression to the fatal fourth 'D'.

The Decline of Pellagra Mortality

The implementation of dietary improvements and food fortification marked the end of the large-scale pellagra epidemics. Starting in the late 1930s and continuing into the 1940s, the mandatory enrichment of flour and other staple food items with niacin was a critical public health intervention.

Historical Pellagra vs. Modern Pellagra


Feature	Historical Pellagra (Pre-1940s)	Modern Pellagra (Post-1950s)
Mortality Rate	High, especially if untreated; death often occurred within 5 years.	Extremely low; death is rare with proper diagnosis and treatment.
Prevalence	Epidemic proportions, particularly in the American South.	Rare in developed countries; primarily found in high-risk groups.
Primary Cause	Severe dietary deficiency, linked to maize-heavy diets and poverty.	Secondary causes like chronic alcoholism, certain drugs, or malabsorption issues.
Treatment	Unknown; often resulted in death without specific intervention.	Easily treated with oral or intravenous niacin/nicotinamide supplementation.
Public Perception	Feared, contagious disease of poverty.	Known nutritional deficiency disease; not contagious.

Modern Risk Factors and Outlook

Today, full-blown pellagra with all four classic Ds is uncommon in regions with fortified food supplies. However, it can still affect vulnerable populations, including chronic alcoholics, individuals with certain gastrointestinal conditions, or those living in extreme poverty in parts of the world where corn is a staple and food fortification is not standard practice. For these at-risk groups, the potential for a high mortality rate still exists if the condition is not recognized and treated in time. However, with modern diagnostic tools and effective treatments, the prognosis for those diagnosed is excellent.

Conclusion

The mortality rate of pellagra was historically high and devastating, claiming thousands of lives during epidemics of the early 20th century. This tragic period of medical history was not ended by a breakthrough in understanding a microbe, but by a simple yet profound discovery about nutrition. The transition from a misunderstood, fatal epidemic to a preventable and treatable condition is a powerful testament to the impact of nutritional science on public health. While pellagra's deadliest days are behind us in most parts of the world, maintaining awareness of its causes remains crucial for protecting the health of all populations, especially those at risk due to diet or socioeconomic factors. For more information on the discovery of the pellagra cause, see the CDC's historical overview.

Frequently Asked Questions

Pellagra is a nutritional disorder caused by a severe deficiency of niacin (vitamin B3), or a deficiency of the amino acid tryptophan, from which niacin can be synthesized.

Pellagra is characterized by the 'four Ds': dermatitis (skin inflammation), diarrhea, dementia, and if left untreated, death.

No, pellagra is not a contagious disease. It is a dietary deficiency disease, though this was not initially understood and was a source of great confusion during the epidemics.

Historically, untreated pellagra had a very high mortality rate. In the American South, approximately 100,000 people died from the disease between 1906 and 1940.

Pellagra was brought under control by the discovery that it was caused by niacin deficiency, followed by widespread dietary improvements and the mandatory fortification of staple food products with niacin.

While rare in developed countries with fortified food supplies, pellagra can still occur in vulnerable populations, including chronic alcoholics and those with severe malnutrition.

Modern pellagra is treated with niacin or nicotinamide supplementation, often leading to a full recovery within days or weeks, depending on the severity.