A vitamin is an organic molecule (or related set of molecules) which is an essential micronutrient—that is, a substance which an organism needs in small quantities for the proper functioning of its metabolism but cannot synthesize, either at all or in sufficient quantities, and therefore must obtain through its diet.
If you are like most people, you’ve probably heard at least one of these sayings: ‘Don’t forget to take your vitamins!’ or ‘Eat your veggies — they are packed with vitamins!’ or maybe ‘Need more energy? Take your vitamins!’ But what exactly are vitamins?
Vitamins are nutrients your body needs to function and fight off disease. Your body cannot produce vitamins itself, so you must get them through food you eat or in some cases supplements. There are 13 vitamins that are essential to your body working well. Knowledge of the different types and understanding the purpose of these vitamins are important for good health.
Types and Examples of Foods
There are two types of vitamins: fat-soluble and water-soluble. Fat-soluble vitamins are stored in your fat cells, consequently requiring fat in order to be absorbed. Water-soluble vitamins are not stored in your body; therefore, they need to be replenished daily. Your body takes what it needs from the food you eat and then excretes what is not needed as waste. Here is a list of some vitamin types and common food sources:
- Vitamin A – comes from orange colored fruits and vegetables; dark leafy greens, like kale
- Vitamin D – can be found in fortified milk and dairy products; cereals; (and of course, sunshine!)
- Vitamin E – is found in fortified cereals; leafy green vegetables; seeds; nuts
- Vitamin K – can be found in dark green leafy vegetables; turnip/beet greens.
Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene).Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system and good vision.Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision. Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells.
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism. Though these vitamins share similar names, they are chemically distinct compounds which often coexist in the same foods. In general, dietary supplements containing all eight are referred to as a vitamin B complex. Individual B vitamin supplements are referred to by the specific number or name of each vitamin: B1 = thiamine, B2 = riboflavin, B3 = niacin, etc. Some are better known by name than number: niacin, pantothenic acid, biotin and folate.
Vitamin C, also known as ascorbic acid and L-ascorbic acid, is a vitamin found in food and used as a dietary supplement.The disease scurvy is prevented and treated with vitamin C-containing foods or dietary supplements. Evidence does not support use in the general population for the prevention of the common cold. There is, however, some evidence that regular use may shorten the length of colds.It is unclear if supplementation affects the risk of cancer, cardiovascular disease, or dementia. It may be taken by mouth or by injection.