The fundamental components of the human diet —the so-called macronutrients: water, carbohydrates, fats, and proteins— were identified almost two hundred years ago by an Englishman named William Prout, a curious fellow who combined chemistry with theology. Even back then, it was clear that some other elements were needed to produce a fully healthy diet. For a long time, no one knew exactly which elements those were, but it was evident that if they were missing from the diet, people were likely to suffer from deficiency diseases like beriberi or scurvy.
Initially, they were called "complementary factors of foods." We now call them vitamins. Vitamins are simply organic chemical substances that, because we cannot produce them ourselves, we need to obtain from our food.
At the dawn of the 20th century, British biochemist Frederick Gowland Hopkins, a man with a curious resemblance to the 8th Marquis of the Guadalquivir Marshes, was busy feeding his laboratory rats. He treated them well with a diet of proteins, fats, carbohydrates, and minerals. Although it was known that these substances were the main components of food, they were not sufficient to maintain health. Something was missing: the rats were succumbing to malnutrition.
In 1906, after discovering that supplementing the diet with some milk caused his rats to grow wonderfully, Hopkins coined the term "auxiliary food factor," something previously unknown but necessary for normal development.
Hopkins was not the first to make such an observation. Between 1878 and 1883, Kanehiro Takaki, a Japanese military doctor, had studied the high incidence of a terrible disease among sailors, characterized by muscle degeneration, heart irregularities, and emaciation, known as "beriberi," a name derived from a native Sri Lankan expression meaning "I can't, I can't," referring to the progressive loss of mobility experienced by those affected.
Takaki discovered that among the 276 men of a ship’s crew whose diet mainly consisted of polished rice (a type of rice ground to remove the bran, germ, and fiber, leaving a starch-rich grain), 169 cases of beriberi developed, with twenty-five deaths within nine months. On another ship, no deaths occurred, and only fourteen cases of the disease were reported. The difference was that the crew of this second ship was given more meat, milk, and vegetables. Takaki concluded that this had something to do with the protein content of the diet, but he was mistaken.
Fifteen years later, Christiaan Eijkman, a Dutch doctor working in Java, observed that chickens fed polished rice also contracted beriberi but recovered when fed brown rice. He thought the starch in polished rice was toxic to the nerves and that the bran contained an antidote. His conclusion, like Takaki's, was wrong.
Casimir Funk, a Polish biochemist who had emigrated to the United States, read an article by Eijkman describing that people who ate brown rice were less susceptible to beriberi than those who ate only completely milled rice. Funk attempted to isolate the responsible substance, and in 1912 he finally succeeded. The compound turned out to belong to a family of molecules called amines, and Funk, convinced they were vital for life, coined the term "vitamin."
Funk suggested that diseases like rickets, pellagra, and scurvy were also caused by vitamin deficiencies, an idea also proposed by Dutch researcher Gerrit Grijns, who continued Eijkman’s work. Both were correct, but their work was not recognized.
In 1929, Hopkins and Eijkman shared the Nobel Prize in Physiology or Medicine for their work on vitamins, but Grijns and Funk were ignored. Funk rightly protested because the Nobel committee awarded the prize to Hopkins for "his discovery of vitamins that stimulate growth," even though Hopkins himself never claimed to be the discoverer of vitamins. It was true: there was no single discoverer; many scientists contributed to the knowledge we now have about vitamins.
In 1913, Elmer McCollum and Marguerite Davis, biochemists at the University of Wisconsin, discovered that rats fed lard as their only fat source did not grow and developed eye problems. When butterfat or an egg yolk extract was added to their diet, growth resumed, and the eye condition was corrected.
McCollum suggested that whatever was present in the ether extract should be called fat-soluble factor "A," and the aqueous extract that Funk had used to prevent beriberi should be called water-soluble factor "B." When it was discovered that the water-soluble extract was a mixture of compounds, its components were designated with numerical subscripts. The specific factor against beriberi was eventually named vitamin B1 or thiamine.
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| Effects of scurvy in the Diary of Henry Walsh Mahon aboard the convict ship Barrosa. |
Vitamin B3, or niacin, was added to the vitamin family in 1914, when American doctor Joseph Goldberger solved the mystery of pellagra, an epidemic in the southern states, particularly in cotton-growing areas. Described as the disease of the four Ds: diarrhea, dermatitis, dementia, and death, it was thought that pellagra was related to cotton, either as a germ or a toxin contained in the plant.
Goldberger, a public health doctor, demonstrated that the disease was actually caused by a diet consisting mostly of corn and could be cured by adding fresh vegetables, milk, and eggs. Twenty years later, in 1937, Norwegian-born American biochemist Conrad Elvejhem identified niacin as the nutrient lacking in corn that was necessary to prevent pellagra.
Although it is known that the Spanish, at least since the early 17th century, regularly used citrus fruits as a method to prevent scurvy, vitamin C, the most famous of all vitamins, was identified in 1932 by Hungarian-American physiologist Albert Szent Gyorgyi, who was awarded the Nobel Prize in Physiology or Medicine in 1937. He extracted the compound from paprika and suggested it be named ascorbic acid, from the Latin "scorbuticus" (scurvy). A year later, British chemist Walter Haworth determined its molecular structure.
Long before the identification of ascorbic acid, in his Treatise on Scurvy, published in 1753, Scottish doctor James Lind described experiments demonstrating that scurvy could be prevented by consuming citrus fruits. This led to British sailors being supplied with lime juice. The Anglo-French Napoleonic Wars are a good example: the British Admiralty provided about six million liters of lemon juice to sailors during the years of that conflict. Sicily actually became a lemonade factory.
Subsequently, other vitamins were identified and given the designations D and E, following the order of their discovery. Vitamin K was named as such because its discoverer, Danish biochemist Henrik Dam, proposed the term "Koagulations Vitamin" due to its promotion of blood coagulation.
Are there still unknown vitamins? It is unlikely. Many hospitalized patients have survived for many years using intravenous nutrition that incorporates the known vitamins. However, the current trend aims to investigate whether, in addition to preventing diseases caused by nutritional deficiency, vitamins may have some supplementary benefit.
It has been suggested that vitamin C may prevent the common cold, vitamin E may reduce the risk of cardiovascular diseases, and vitamin D is a sort of cure-all. None of these claims are backed by convincing scientific evidence, but that hasn’t stopped vitamin supplements from flourishing into a multimillion-dollar industry.
The main debate around vitamins was sparked by American chemist Linus Pauling, who had won not one, but two Nobel Prizes (the Chemistry Prize in 1954 for his work describing chemical bonds, and the Peace Prize eight years later for his defense of human rights). In a striking example of a cobbler not sticking to his trade, Pauling believed that taking massive doses of vitamin C was effective in fighting colds, flu, and even certain types of cancer.
Pauling himself took up to 40,000 milligrams of vitamin C daily (the recommended daily dose is 60), and claimed that this enormous intake had kept his prostate cancer at bay for twenty years. He had no evidence for any of his claims, and all of them have been largely discredited by subsequent studies. But thanks to Pauling, many people still believe that taking a lot of vitamin C helps them avoid colds. But it doesn’t.
