Vitamins: What Are They And What Do They Do?

Vitamins are organic compounds that are needed in small quantities to sustain life. Most vitamins need to come from food.

This is because the human body either does not produce enough of them, or it does not produce any at all.

Each organism has different vitamin requirements. For example, humans need to consume vitamin C, or ascorbic acid, but dogs do not. Dogs can produce, or synthesize, enough vitamin C for their own needs, but humans cannot.

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People need to get most of their vitamin D from exposure to sunlight, because it is not available in large enough quantities in food. However, the human body can synthesize it when exposed to sunlight.

Different vitamins have different roles, and they are needed in different quantities.

This article explains what vitamins are, what they do, and which foods provide each type. Follow the links for more information about each type of vitamin.

Fast facts on vitamins

Here are some key points about vitamins. More detail and supporting information is in the main article.

There are 13 known vitamins.

Vitamins are either water-soluble or fat-soluble.

Fat-soluble vitamins are easier for the body to store than water-soluble.

Vitamins always contain carbon, so they are described as "organic."

Food is the best source of vitamins, but some people may be advised by a physician to use supplements.

What are vitamins?

A vitamin is one of a group of organic substances that is present in minute amounts in natural foodstuffs. Vitamins are essential to normal metabolism. If we do not take enough of any kind of vitamin, certain medical conditions can result.

A vitamin is both:

- an organic compound, which means it contains carbon

- an essential nutrient that body cannot produce enough of and which it needs to get from food

There are currently 13 recognized vitamins.