While there has always been an understanding of a connection between food and human health, it took a long time for science to catch up. Isolating the exact compounds in food, that provide a particular form of nutrition, didn't occur in earnest until the early 1900s. The resulting hard work of scientists in the first half of the 20th century initiated the beginning of our modern-day understanding of vitamins—named after letters of the alphabet, with some including numbers, too.
Curious? Click on to learn about when vitamins were discovered, why they are named after letters, and what scientists found out about their function.
Polish-born biochemist Casimir Funk coined the word "vitamine" in 1911, what we understand today as vitamin. By isolating a chemical amine in chicken food, he discovered the resulting deficiency that occurred.
But long before Funk, Gerardus Johannes Mulder, a Dutch chemist, proposed that protein played a principal role in health, in 1838.
Over the following decades, new knowledge about nutrition was learned as it was observed that fruit, vegetables, and dairy helped to cure scurvy and rickets. However, protein was still thought to be the "true nutrient" of health.
Sailors on long voyages also suffered with beriberi, a condition where they lost sensation in the legs and feet and suffered heart failure. It was observed poorer sailors fared worse, and it was presumed a lack of protein was the reason.
Professor Christian Eijkman, a Dutch army doctor, observed what happened to the health of chickens who ate white rice in comparison to those who were fed brown, unprocessed rice, with the bran still intact.
He found the chickens fed white rice suffered beriberi, and later noted they had this in common with human prison populations who were fed white rice. This paved the way for Casimir Funk's findings about amines, and the vitamin discoveries that were to follow.
The first vitamin discoveries are so-called due to it being referenced as such in a master's thesis by Cornelia Kennedy. She was the mentee of Elmer McCollum, the person credited with discovering vitamin A. She used the "A" and "B" denominations to differentiate between the two types of vitamins being discussed in her thesis. The names stuck, and continued to be used by McCollum and others, leading to new vitamins being named the same way as they were discovered.
Japanese researcher Umetaro Suzuki was the first person to discover vitamin B1 by isolating aberic acid in rice. After taking away the water-soluble thiamine compound from rice bran, beriberi was observed in those who consumed it.
Casimir Funk went on to isolate the thiamine from rice bran in 1911, but it wasn't until 1926 that chemists Barend Coenraad Petrus Jansen and Willem Frederik Donath isolated the active agent. In 1934, Robert Runnels Williams determined the structure of what we know to be B1/thiamine today.
Vitamin A was discovered as a fat-soluble fraction of foods, that was found necessary for the growth and survival of young rats during experimentation.
At the time of discovery, the vitamin hypothesis of Casper Funk had become popular. McCollum’s discovery of vitamin A was the first isolated food compound shown to prevent deficiency disease.
Albert Szent-Györgyi discovered the chemical ascorbic acid—also known as vitamin C—that enables the body to efficiently use carbohydrates, fats, and protein.
Vitamin C was the very first vitamin to be industrially produced for supplementation. Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine in 1937 for his discovery.
Initially, what we now understand to be vitamin D had been part of the earliest scientist's understanding of vitamin A. Only after experimentation with cod liver oil were the two factors separated.
The factor in cod liver oil that was found effective against rickets was recategorized and labeled vitamin D. Within a decade, the fortification of foods with vitamin D was underway in the US.
Vitamin B2 (riboflavin) was discovered in 1922 by Richard Kuhn in Germany and Theodor Wagner-Jauregg in Austria, although its essential nature was not fully understood until later.
The B2 compound was later isolated from the rest of the other B vitamins in 1933 in Germany, by Kuhn and colleague Paul György.
In 1922, vitamin E was discovered by Herbert McLean Evans and Katharine Scott Bishop. It originally was used to described the compounds of antioxidant activity of α-tocopherol.
In 1935 at the University of California, Berkeley, vitamin E was isolated in a pure form for the first time by Evans and Gladys Anderson Emerson.
Vitamin K was found by Carl Peter Henrik Dam during his research at the Biochemical Institute of the University of Copenhagen between 1928 and 1930.
The finding advanced the understanding of blood coagulation and produced a new lifesaving therapy for bleeding diseases. The "K" was chosen to represent the Danish "koagulation," hence why it's not called vitamin F.
Dr. R. J. Williams discovered B5/pantothenic acid in 1933. The name is derived from the Greek word pantos, which means "from all quarters."
Pantothenic acid was later identified as a component part of the fatty acid synthesis complex. Its functional forms were recognized as coenzyme A (CoASH) and 4′-phophopantotheine, a component of acyl carrier protein (ACP).
Vitamin B6/pyridoxine was discovered in 1934 by Paul György (who had isolated vitamin B2 a year prior) and his colleagues.
The active compound was first isolated a few years later, in 1938, by Samuel Lepovsky of the University of California, Berkeley.
Originally called vitamin H when the compound was first found by Paul György in 1931, what we know today as B7/biotin was first isolated in its pure form in 1935.
German-Dutch biochemist Fritz Kögl and his graduate student Benno Tönnis, at Utrecht University, isolated a crystalline substance they believed to be part of the 'bios' factor and named it biotin. Later, it was found to be identical to vitamin H.
American biochemist Conrad Arnold Elvehjem discovered the structure of nicotinic acid, later shortened to "niacin," a combination of nicotonic and vitamin.
In 1941, folate/B9 was first isolated from spinach. The scientists who purified this new vitamin decided to name it folic acid, from the Latin word for leaf, folium.
Vitamin B12 was first isolated in 1948 by American chemist Karl Folkers and British chemist Baron Alexander Todd. A year after its discovery, this new compound was tested on a patient who suffered from pernicious anemia, curing her.
Cobalamins/B12 was later found to be a key growth factor in animals, leading farmers to fortify livestock diets with the vitamin.
Sources: (National Geographic) (Britannica) (American Chemical Society) (ScienceDirect) (Netmeds) (Medicine LibreTexts) (National Library of Medicine) (Oxford Academic)
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While there has always been an understanding of a connection between food and human health, it took a long time for science to catch up. Isolating the exact compounds in food, that provide a particular form of nutrition, didn't occur in earnest until the early 1900s. The resulting hard work of scientists in the first half of the 20th century initiated the beginning of our modern-day understanding of vitamins—named after letters of the alphabet, with some including numbers, too.
Curious? Click on to learn about when vitamins were discovered, why they are named after letters, and what scientists found out about their function.