Elmer McCollum

Elmer Verner McCollum was a prominent American biochemist who revolutionized our understanding of nutrition.

He focused his career on how specific components in a diet influence the health and growth of living things. During his era, the concept of vitamins was almost entirely unknown to the scientific community. McCollum sought to answer fundamental questions about how many dietary essentials exist and what their specific identities are. His research helped transform nutrition from a series of guesses into a precise science. Because of his massive impact, he was often referred to by the nickname "Dr. Vitamin."

McCollum's path to discovery began with the observations made during the single-grain experiment in Wisconsin.

This study was led by Stephen Babcock and later Edwin B. Hart at the University of Wisconsin Dairy Barn. At the time, many chemists believed that any food containing specific amounts of protein, carbohydrates, fats, and salts was sufficient for animals. Babcock challenged this idea, suggesting that something more complex was required for health. To test this, researchers divided sixteen calves into four distinct groups. One group ate only wheat, one ate only oats, and one ate only corn. A fourth group received a mixture of all three grains.

The results of the single-grain experiment were startling and provided a critical clue for future research.

While the corn-fed group thrived, the wheat and oat groups became weak, and their offspring often died. The mixed-grain group performed better than the single-grain groups but was not as successful as the corn group. When the weak cows were switched to a corn diet, they recovered and produced healthy calves. Despite these clear results, the researchers in 1911 stated they had no immediate solution for these observations. McCollum concluded that a fundamental, undiscovered element must be missing from certain diets.

To find this missing element, McCollum turned to animal models that could provide quick results. He decided to establish a colony of rats for his nutrition research. He chose rats because they are omnivorous, inexpensive to feed, and mature very rapidly.

In January 1908, he started the first rat colony in the United States dedicated to nutrition studies. He began by purchasing twelve domesticated albino rats from a Chicago pet store for six dollars. This work was a significant departure from his earlier studies of cow feed and milk. He worked closely with Marguerite Davis, a student who helped him develop the biological method for food analysis.

In 1913, McCollum and Davis achieved a breakthrough by identifying a specific growth factor. They fed rats diets consisting of pure casein, carbohydrates, and salts, but lacked certain fats. They observed that while the rats appeared healthy, they eventually stopped growing. Most importantly, the female rats could not produce enough milk to nourish their young. However, when they added small amounts of egg or butter extract to the diet, the rats resumed normal growth.

They originally called this substance "factor A," which was later identified as vitamin A. This discovery was part of a larger effort that also helped identify vitamin B and vitamin D.

McCollum's scientific influence extended far beyond the laboratory and into the daily lives of the public. He was a strong advocate for consuming milk, calling it "the greatest of all protective foods." This advocacy had a measurable impact, as milk consumption in the United States doubled between 1918 and 1928. He also promoted the importance of eating leafy green vegetables to ensure a balanced diet. McCollum even suggested that a properly planned lacto-vegetarian diet could be a highly satisfactory way to nourish humans. His work helped bridge the gap between complex biochemistry and practical dietary habits.

Throughout his career, McCollum moved from being an instructor to a full professor at the University of Wisconsin. His academic journey included earning a bachelor's degree from the University of Kansas and a Ph.D. from Yale University. He spent time as a postdoctoral researcher studying plant protein before settling into agricultural chemistry. His life's work connects the study of trace elements and chemical compounds to the fundamental biological need for growth. By identifying the specific roles of vitamins, McCollum provided the tools necessary to prevent deficiency diseases and optimize human health.