What Is This Thing You Call A Vitamin?
Vitamins are chemicals that your body needs in order to survive. They perform (or aid in performing) certain vital tasks inside the cell. Unfortunately, your body either cannot make these chemicals at all or cannot produce enough of them to get by on its own. This is why we have to ingest these chemicals (vitamins) in the food we eat.
Some History On Vitamin(e)s
People have had a general understanding for several hundred years that the consumption of certain foods prevents certain diseases. They did not know how exactly the food prevented the disease, they merely knew that it did. Two examples: In the 1700s people found out that scurvy could be prevented by the consumption of citrus fruits, most famously limes. During the 1800s people discovered that beriberi could be prevented by eating unpolished rice instead of polished rice (more on the rice bit later). The reasons why these foods (among others) prevented certain diseases remained unknown until 1906. Enter British biochemist Frederick Hopkins. He proved that food contains things he referred to as "accessory factors" in addition to the already known carbohydrates, minerals, proteins, fats and water. The specific "factors" which Hopkins discovered aid in the complete digestion of food into usable chemical forms. Five years later, Casimir Funk, a Polish chemist, discovered that the "accessory factor" in unpolished rice that prevented beriberi was an amine (a certain kind of nitrogen-containing compound). Since the amine seemed essential to proper body function, Funk referred to it as a vitamine (vital amine). Further vitamines were discovered, and they were assigned alphabetic names. However, not all of these vitamines were actually amines. By the time this was known, the name vitamine had become too popular to change, so the "e" was dropped to make it the vitamin we know today.
Divisions Of Vitamins
Fat-soluble vitamins are easily stored by the body. Vitamin E is held in reproductive organs and fat, while the liver holds large amounts of vitamins A and D.
Water-soluble vitamins cannot easily be stored, since they are, by definition, water-soluble. They easily pass through the body in urine, so you must eat them everyday.
Vitamin A (retinol)-sources include green vegetables, carrots, dairy products and animal fat; needed for good vision, proper organ function and immune system health.
Vitamin B complex (B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6, biotin, folacin, and B12 (cobalamin))-sources include cereals, meats, dairy products and green vegetables; needed for intracellular (inside the cell) activities and healthy skin.
Vitamin C (ascorbic acid)-sources include vegetables and fruit, especially tomatoes and citrus fruits; needed for wound-healing, tendon and tissue growth, and healthy gums, teeth and blood.
Vitamin D-sources include skin exposed to sunlight, eggs, fish, and butter; needed for calcium and phosphorous absorption control (necessary in controlling bone formation).
Vitamin E-sources include wheat germ, margarine, rice, and green, leafy vegetables; needed for...(vitamin E is still something of a mystery, but guesses on why we need it include reproductive organ health and neuromuscular functions).
Vitamin K-sources include beneficial organisms that live in the human intestines, also egg yolks, fish liver, leafy green vegetables, and yogurt; needed for proper creation of blood-clotting proteins
Recommended Daily Allowances (RDAs)
- Vitamin A: Men 1 mg; Women .7 mg
- B1 (Thiamine): Men 1.2 mg; Women 1.1 mg
- B2 (Riboflavin): Men 1.3 mg; Women 1.1 mg
- B3 (niacin): Men 16 mg; Women 14 mg
- B5 (pantothenic acid): Men 5 mg; Women 5 mg
- B6: Men 1.7 mg; Women 1.5 mg
- Biotin: Men .1 mg; Women .1 mg
- Folacin: Men .4 mg; Women .4 mg
- B12 (cobalamin): Men .003 mg; Women .003 mg
- Vitamin C: Men 90 mg; Women 75 mg
- Vitamin D:1
- Vitamin E: Men 30 IU;2 Women 30 IU
Vitamin K: Since it is primarily produced inside the body, vitamin K has no established RDA.
These amounts may be somewhat incomprehensible, seeing as how small some of them are, so it is somewhat difficult to put all of this in perspective. Most people get by well with eating a good variety of food and perhaps taking a multi-vitamin. Obviously, a doctor may prescibe more or less of a certain vitamin for different people.
Vitamin Deterioration and Enhancement
When subjected to cooking or heavy refining, some vitamins tend to be destroyed. Vitamin C, along with other heat-susceptible vitamins, often has a markedly reduced presence in cooked foods. On the other hand, some nutrients flourish when cooked. Carotenoids3 (e.g. lycopene, lutein) are often released in greater numbers in cooked foods, making more available for absorption. Heavy refining or milling of grain also reduces the vitamin and mineral content.
significantly different requirements depending on how
old you are. Here are the RDAs for Vitamin D.
200 IU for adults (both sexes) for ages 20-50
400 IU for adults (both sexes) for ages 50-70
800 IU for adults (both sexes) for ages >70
2The IU (International Unit) is an arbitrary measure. One should find the amount of IUs a certain vitamin has on its labeling.3Carotenoids are pigments in foods. They are generally involved in the human body as antioxidants, protecting cells from the harmful effects of free radicals and singlet oxygen. Some carotenoids also form building blocks for body-manufactured vitamins.