How a Corn-Based Diet Led to Mental Illness

In his encyclopedic tome Anatomy of Melancholy (1621), the Oxford don Robert Burton (1577-1640) wrote a great deal about how diet could have an impact on mental health. A sufferer of melancholia himself, Burton explained that some foods could exacerbate his symptoms most gravely. Dietary changes could make a great difference.

Burton's frame of reference was humoral medicine. While we might chuckle a little at some of his suggestions today, the relationship between food and mental health is topical once again, with the gut-brain axis at the heart of recent research. Scientists are concerned that the overconsumption of ultra-processed food might be negatively affecting our gut microbiome, with poor implications for mental (as well as physical) health.

A girl suffering from pellagra

Source: Wellcome Images/Wikimedia Commons, CC BY 4.0 DEED

Overconsumption of another food also caused considerable mental disturbance in the past: corn. In northern Italy and the American South, the mass planting of corn as a cash crop had a detrimental effect on the health of impoverished local populations. When corn replaced other grains in the diets of such people, they fell victim to niacin deficiency.

The end result was pellagra, which in its final stages, resulted in madness. Many people languishing in asylums in these two regions were simply suffering from vitamin deficiency. But this wasn't known just yet.

Pellagra is a cautionary tale in many ways. Chiefly, it demonstrates how insufficient diets can be catastrophic for the brain, especially for people who are unable to diversify their diet.

But it is also a tale about science. In both Italy and the American South, it took far longer to come to grips with pellagra than it should have. This is because science never operates in a vacuum: It is also affected by political, economic, and cultural factors.

In the case of Italy, a number of hypotheses were presented to explain what caused pellagra, which means "rough skin." It is worth noting that these ideas were developed in the nineteenth century before the "discovery" of the vitamin by Casimir Funk (1884-1967) and the subsequent identification of vitamin deficiency diseases in the 1910s. Even though a deficiency theory of pellagra had been identified by Filippo Lussana (1820-1897), the theory of Cesare Lombroso (1835-1909) that pellagra was caused by spoiled corn overshadowed it. The reason for this was primarily down to Lombroso's fame and scientific celebrity.

Joseph Goldberger

Source: Centers for Disease Control and Prevention/Wikimedia Commons, Public domain

In the U.S., pellagra was endemic in the South. In 1915, Joseph Goldberger (1874-1929) was tasked by the Surgeon General to research the disease. Goldberger's experiments determined that pellagra was caused by corn-based diets, which were, in turn, the product of poverty.

Unfortunately for Goldberger (and especially poor Southerners), Southern authorities were loath to listen to a Jewish Northerner's views on the insufficiency of the Southern diet. As Mary Katherine Crabb has explained, pellagra was an "epidemic of pride" in the South. It took another 15 years for pellagra to finally be eradicated.

Today, few people suffer from pellagra in northern Italy or the American South. The disease still afflicts people in some parts of the world where diets are insufficient, such as sub-Saharan Africa.

The story of pellagra, however, remains highly relevant today. It reminds us that diet and mental health are linked, often in complex, mysterious ways. It represents yet another way that poverty can lead to poor mental health.

Pellagra also reminds us that science can be influenced by trends, politics, big personalities, and even prejudice. This remains the case today. Critical thinking, therefore, is a key part of the scientific process.