To take or not to take, that is the question often asked about vitamin supplements. Some experts suggest that a balanced diet provides all the vitamins we need, while others claim that a daily multivitamin pill provides nutritional insurance. Then there are those who allege that vitamins can both prevent or cure a variety of diseases while others point to studies that imply vitamins are linked with greater morbidity. Too much confusion to clear up in one short lesson. But the confusion about the term 鈥渧itamin鈥� can be addressed. Indeed, it is a misnomer. Vitamins are 鈥渧ital,鈥� but they are not necessarily amines.
鈥淰itamin鈥� derives from the Latin 鈥渧ita鈥� for life and 鈥渁mine,鈥� the name for a family of nitrogen containing organic compounds. But as it turns out, not all vitamins are amines. The very first one, isolated from rice hulls by biochemist Casimir Funk in 1912 was indeed an amine and was given the name 鈥渢hiamine.鈥� Funk thought that there likely were other amines essential to life that had to be supplied by the diet and suggested the term 鈥渧itamine鈥� be used to describe them. He was right about the existence of other 鈥渧itamines,鈥� but when it turned out that they were not all amines, the 鈥渆鈥� was dropped from the name.
Funk鈥檚 discovery takes us back to the late nineteenth century when the mechanized rice mill was introduced in Asia . It produced attractive white rice, but it also produced a new disease that came to be called 鈥渂eriberi鈥�. In the native language of Sri Lanka, beriberi means 鈥渨eakness鈥�, and describes a condition of progressive muscular degeneration, heart irregularities and emaciation. Kanehiro Takaki, a Japanese medical officer, studied the high incidence of the disease among sailors in the Japanese navy from 1878-1883 and discovered that on a ship where the diet was mostly polished rice, among 276 men, 169 cases of beriberi developed and 25 men died during a nine-month period.聽 On another ship, there were no deaths and only 14 cases of the disease.聽 The difference was that the men on the second ship were given more meat, milk and vegetables.聽 Takaki thought this had something to do with the protein content of the diet, but he was wrong.
About 15 years later a Dutch physician in the East Indies , Christiaan Eijkman, noted that chickens fed mostly polished rice also contracted beriberi but recovered when fed rice polishings.聽 He thought that the starch in the polished rice was toxic to the nerves, but he was wrong.聽 And that鈥檚 when Casimir Funk entered the picture. The Polish-born biochemist determined that it wasn鈥檛 something that was present in white rice that was the problem, it was something that was absent, namely the outer coating, the rice 鈥渉ulls.鈥� Funk managed to show that an extract of rice hulls prevented beriberi and introduced the term 鈥渧itamine鈥� for substances in food that could prevent specific diseases.
A short time later, E.V. McCollum and Marguerite Davis at the University of Wisconsin discovered that rats given lard as their only source of fat failed to grow and developed eye problems. When butterfat or an ether extract of egg yolk was added to the diet, growth resumed and the eye condition was corrected. McCollum suggested that whatever was present in the ether extract be called fat soluble 鈥淎,鈥� and that the water extract Funk had used to prevent beriberi, be called water-soluble factor 鈥淏.鈥� When the water-soluble extract was found to be a mixture of compounds, its components were given designations with numerical subscripts. The specific anti-beriberi factor was eventually called vitamin B1, or thiamine. These 鈥渧itamins鈥� had a common function. They formed part of the various enzyme systems needed to metabolize proteins, carbohydrates and fats. Some of the compounds in Funk鈥檚 water extract eventually turned out to offer no protection against any specific disease and their names had to be removed from the list of vitamins. As other water soluble substances which were required by the body were discovered, they were added to the B vitamin list.
Other vitamins were subsequently identified and given the designations C, D and E in order of their discovery.聽 Vitamin K was so called because its discoverer, the Danish biochemist Henrik Dam, proposed the term 鈥淜oagulations Vitamin鈥� because it promoted blood coagulation.聽 Are there still unrecognized vitamins?聽 Not likely.聽 Patients have now been successfully kept alive for many years through total parenteral nutrition ( TPN ) which involves using an intravenous formula that incorporates the known vitamins.
And what then about those daily vitamins that are so heavily advertised? They don鈥檛 kill and they don鈥檛 cure. But they may fill in some nutritional gaps in a less than ideal diet. And nobody really knows what an ideal diet is.
