Who is most likely to get pellagra?

October 15, 2025 •

2 min read

According to the World Health Organization, pellagra remains an endemic issue in certain regions, primarily affecting populations with limited access to diverse food sources. Who is most likely to get pellagra depends heavily on lifestyle factors, dietary habits, and underlying health conditions that interfere with niacin (vitamin B3) or tryptophan absorption.

Quick Summary

Chronic alcoholism, restrictive diets, and malabsorptive conditions are the primary risk factors for pellagra, a systemic disease caused by niacin deficiency. Vulnerable populations in less developed regions relying on unfortified corn or sorghum are also at high risk.

Key Points

Chronic Alcoholism: Heavy alcohol use is the most common cause of secondary pellagra in developed countries due to poor diet and nutrient malabsorption.
Food-Insecure Populations: People living in poverty or relying on a staple diet of untreated corn or sorghum, particularly in developing countries, are at highest risk of primary pellagra.
Malabsorptive Conditions: Gastrointestinal diseases like Crohn's, bariatric surgery, and chronic diarrhea can severely impair niacin absorption, leading to secondary pellagra.
Certain Medications: Long-term use of specific drugs, including some anti-tuberculosis and chemotherapy agents, can interfere with niacin metabolism.
Eating Disorders: Individuals with anorexia nervosa or other severe eating disorders are highly susceptible to pellagra due to severe nutritional deficiencies.
Genetic Disorders: Rare hereditary conditions like Hartnup disease impair the body's ability to transport amino acids, including tryptophan, a niacin precursor.
Systemic Impact: Pellagra presents with the "4 Ds": dermatitis, diarrhea, dementia, and if left untreated, death, affecting multiple bodily systems.

Primary vs. Secondary Causes: Understanding the Risk

Understanding who is most likely to get pellagra requires differentiating between primary and secondary deficiencies. Primary pellagra results from a diet low in niacin and tryptophan, often seen in regions where untreated corn or sorghum is a staple. Secondary pellagra, more common in developed countries, occurs when underlying conditions hinder the absorption or use of niacin despite adequate dietary intake.

Key Risk Factors for Pellagra

Several groups are at increased risk of developing pellagra:

Chronic Alcoholism

Chronic alcohol use is a significant cause of secondary pellagra in developed nations. It contributes to poor dietary intake of niacin, impairs its absorption, and disrupts the conversion of tryptophan to niacin.

Malnutrition and Limited Diets

Primary pellagra is a concern in food-insecure populations and regions relying on untreated corn or sorghum, such as parts of sub-Saharan Africa and Asia. Displaced populations and individuals with restrictive eating disorders like anorexia nervosa are also at high risk due to limited food intake.

Medical Conditions Affecting Absorption or Metabolism

Certain medical conditions and procedures can lead to secondary pellagra by interfering with nutrient absorption or metabolism. These include gastrointestinal diseases like Crohn's and ulcerative colitis, bariatric surgery, genetic disorders like Hartnup disease, carcinoid syndrome, and liver cirrhosis.

Drug-Induced Pellagra

Some medications can interfere with niacin metabolism. Anti-tuberculosis drugs such as isoniazid and ethionamide, as well as certain chemotherapy and immunosuppressant drugs, can increase the risk of niacin deficiency.

Comparison of Primary vs. Secondary Pellagra Risk Factors


Risk Factor Type	Primary Pellagra	Secondary Pellagra
Dietary Intake	Caused by direct lack of niacin and tryptophan in the diet.	Adequate dietary intake, but the body cannot absorb or use it properly.
Associated Population	Impoverished communities, displaced people, those relying on single staple crops (e.g., untreated corn).	Chronic alcoholics, individuals with eating disorders, and patients with specific medical conditions.
Underlying Mechanism	Insufficient intake or inability to access bioavailable niacin from food.	Malabsorption, impaired metabolism, or drug interactions preventing niacin utilization.
Typical Setting	Historically, endemic in parts of the world where unfortified corn was a staple; today, seen in developing regions.	More common in developed countries where dietary niacin is generally sufficient but secondary health issues exist.

Conclusion

While primary pellagra is less common in industrialized nations due to fortified foods, it remains a concern in developing regions. In developed countries, individuals with chronic alcoholism, eating disorders, malabsorptive conditions, or those on certain medications are most likely to get pellagra. Early diagnosis and treatment, which includes niacin supplementation and addressing the underlying cause, are essential for reversing symptoms and preventing severe complications.

For more information on nutritional disorders, including causes and treatments, consult authoritative health resources like the Cleveland Clinic's pellagra article.

Frequently Asked Questions

The primary cause of pellagra is a diet deficient in niacin (vitamin B3) and its precursor, the amino acid tryptophan.

Niacin in untreated corn is in a 'bound' form that is not bioavailable for human absorption. Traditional alkaline processing methods, like nixtamalization, are needed to release the niacin.

Chronic alcoholism can cause pellagra by leading to poor nutrition, impairing the absorption of niacin in the gut, and disrupting the metabolic conversion of tryptophan into niacin.

Yes, some medications, including anti-tuberculosis drugs like isoniazid and ethionamide, can disrupt niacin metabolism and cause deficiency.

Medical conditions that cause malabsorption, such as Crohn's disease, chronic diarrhea, and bariatric surgery, can increase the risk of secondary pellagra.

While rare in developed countries with fortified foods, primary pellagra persists in impoverished regions, and secondary pellagra occurs sporadically in developed nations among high-risk groups.

The classic symptoms are often referred to as the '4 Ds': dermatitis (skin rash), diarrhea, dementia, and, if untreated, death.