One example is pellagra.  Pellagra (sometimes called pelegra) is a disease characterized externally by diarrhea, dementia, hair loss, and skin lesions. The blood of a patient suffering from pellagra appears slightly anemic.  In the early 1900’s several outbreaks of pellagra occurred in the United States.  One was at the Mount Vernon Hospital for the Colored Insane in Alabama, where 88 cases were reported in 1906.  Of these, well over half died within a few years from the ailment.  None of the hospital’s staff were afflicted.  Between 1907 and 1912 about 25,000 cases of pellagra had been diagnosed in the United States, and about 40% died.

The cause of pellagra was a mystery.  The disease was associated with corn, it seemed to occur in people who ate a lot of corn.   One popular hypothesis was that spoiled corn harbored some type of pathogen that caused the disease.

Joseph Goldberger, a physician with the US Public Health Service began a study of Pellagra in 1914.  He started strictly with

Dr Joseph Goldberger was an epidemiologist in the US (1874 – 1929). From the CDC Public Health Image Library. Image credit: CDC (PHIL #8164).
Dr Joseph Goldberger (1874-1929)  was an epidemiologist in the US. From the CDC Public Health Image Library (PHIL #8164).

observations.  He noted the association with corn, the presence of “outbreaks” in confined population, along with the absence of the disease in the staff members at these confined populations.  He posited that pellagra was caused by a poor diet.  He reasoned that the major difference between the staff and the patients at Mount Vernon Hospital was their diet.

Goldberger first tested his hypothesis at two orphanages in Mississippi where pellagra was frequently diagnosed.  He added fresh meat and vegetables to the diet for these children and within six months saw the virtual elimination of the disease in those populations.  Some were still not convinced.

Goldberger went one step further.  He wanted to introduce pellagra in healthy people.   He recruited 12 prisoners from the Mississippi State Penitentiary to partake in his experiment.  In return for a pardon from the Governor of Mississippi, the prisoners agreed to go for six months on a monotonous diet of cornmeal only.  They would only eat corn.  After six months, six of the eleven had pellagra.  One quit the study before it finished.

By 1915, the conclusions were clear.  Pellagra was caused by a dietary insufficiency.  It would take another 25 years before Conrad Elvehjem isolated the key factor, niacin.  The absence of niacin from a person’s diet leads to pellagra.  Corn has some niacin, but as agriculture was industrialized, new factors were introduced.  On reason for the early 20th century outbreaks of pellagra may have been the new industrialization.  In the early part of the 20th century the Beall Company invented a machine for the process

A 1915 article from The Manning Times (South Carolina) describes Joseph Golderger's findings.
A 1915 article from The Manning Times (South Carolina) describes Joseph Golderger’s findings.

ing of corn, the Beall degerminator.  This machine gave birth to a new way to process corn, called the Tempering-Degerming Milling Process.  This new process separated corn into different products: grits, meals, flour, and germ. These components have substantially longer shelf life than non-degermed corn, which allowed corn to be incorporated into new foods easily and cheaply.  These new foods sometimes became the staple diet for impoverished and institutionalized people.  It eventually became apparent that people who relied on this form of corn were missing an essential component of their diet.  The degerming machine inadvertently reduced the niacin from the corn, resulting in pellagra in those who relied chiefly on corn for their diet.