Vitamins are organic (carbon containing) compounds required in minute amounts to sustain normal metabolism. They can not be synthesized in the body, and must be ingested as part of the diet. Vitamins are known by letter names, and are either fat-soluble (vitamins A, D, E, and K) or water-soluble (the vitamin B complex and vitamin C). The recommended dietary allowance of most vitamins ranges from a few micrograms to a few milligrams.
- Vitamin A, which is found in fish-liver oils, is needed for night vision.
- Vitamin K promotes blood clotting, and can be obtained from leafy green vegetables.
Like vitamins, dietary minerals are essential nutrients needed in small quantities for physiological processes, but minerals are simple inorganic chemical elements, not complex organic molecules. Some minerals, such as calcium, sodium, chlorine, and potassium, have RDAs up to several grams. Carbon, hydrogen, nitrogen, and oxygen aren’t considered minerals because they are required in large quantities, not trace amounts, and because they are the constituents of organic molecules.
- Magnesium is involved in processing adenosine triphosphate. Nuts, soy beans, and chocolate are good sources of magnesium.
- Iron deficiency can result in anemia. Iron is found in red meat, eggs, and oysters.