We include products we think are useful for our readers. If you buy through links on this page, we may earn a small commission. Vitamins are organic compounds that people need in small quantities.
Most vitamins need to come from food because the body either does not produce them or produces very little. Each organism has different vitamin requirements. For example, humans need to get vitamin C from their diets — while dogs can produce all the vitamin C that they need.
For humans, vitamin D is not available in large enough quantities in food. The human body synthesizes the vitamin when exposed to sunlight, and this is the best source of vitamin D. Different vitamins play different roles in the body, and a person requires a different amount of each vitamin to stay healthy. This article explains what vitamins are, what they do, and which foods are good sources.
What Are Vitamins?
Having too little of any particular vitamin may increase the risk of developing certain health issues. A vitamin is an organic compound, which means that it contains carbon. There are currently 13 recognized vitamins.
Fat-Soluble And Water-Soluble Vitamins
Vitamins are either soluble, or dissolvable, in fat or water. The body stores fat-soluble vitamins in fatty tissue and the liver, and reserves of these vitamins can stay in the body for days and sometimes months. Dietary fats help the body absorb fat-soluble vitamins through the intestinal tract.
Water-soluble vitamins Water-soluble vitamins do not stay in the body for long and cannot be stored. Because of this, people need a more regular supply of water-soluble vitamins than fat-soluble ones. Vitamin C and all the B vitamins are water-soluble .
Vitamin supplements Many people in the United States take multivitamins and other supplements, though these may not be necessary or helpful, according to research . The Department of Health and Human Services provide up-to-date guidelines detailing the best ways to get enough nutrients from the diet. Fortified foods and supplements may be appropriate in some cases, however, such as during pregnancy, for people with restricted diets, and for people with specific health issues.
Anyone taking supplements should be careful not to exceed the maximum dose, as research shows that taking too much of any vitamin can lead to health problems. Various supplements are available for purchase online.
Biological Significance Of Vitamins
In 1906–07 British biochemist Sir Frederick Gowland Hopkins observed that animals cannot synthesize certain amino acids and concluded that macronutrients and salts could not by themselves support growth.
Funk believed that some human diseases, particularly beriberi, scurvy, and pellagra, also were caused by deficiencies of factors of the same chemical type. Because each of these factors had a nitrogen-containing component known as an amine, he called the compounds “vital amines,” a term that he later shortened to “vitamines.” The final e was dropped later when it was discovered that not all of the vitamins contain nitrogen and, therefore, not all are amines.
Discovery And Original Designation
Some of the first evidence for the existence of vitamins emerged in the late 19th century with the work of Dutch physician and pathologist Christiaan Eijkman.
In 1890 a nerve disease (polyneuritis) broke out among his laboratory chickens. He noticed that the disease was similar to the polyneuritis associated with the nutritional disorder beriberi. In 1912—the same year that Hopkins published his findings about the missing nutrients, which he described as “accessory” factors or substances—a Polish scientist, Casimir Funk, demonstrated that polyneuritis produced in pigeons fed on polished rice could be cured by supplementing the birds’ diet with a concentrate made from rice bran, a component of the outer husk that was removed from rice during polishing.
Funk believed that some human diseases, particularly beriberi, scurvy, and pellagra, also were caused by deficiencies of factors of the same chemical type. Because each of these factors had a nitrogen-containing component known as an amine, he called the compounds “vital amines,” a term that he later shortened to “vitamines.” The final e was dropped later when it was discovered that not all of the vitamins contain nitrogen and, therefore, not all are amines.