What Are The Major Vitamins?

There are 13 essential vitamins, all necessary for human health. According to the Harvard School of Public Health, a varied, healthy diet, a good multivitamin with minerals and an additional vitamin D supplement can ensure that you get the vitamins your body requires. Consult a qualified health care practitioner about the use of vitamin supplements.

Vitamin A

Vitamin A is best known for its role in promoting good eyesight, but it has many other functions in the body. The textbook "Nutrition: Concepts and Controversies" explains that this vitamin is necessary for gene transcription, immune defenses, normal cell development and reproduction. Vitamin A occurs in foods of animal origin, including fish oil, liver and milk products, and in vegetables such as carrots, sweet potatoes and spinach.

B Vitamins

The B vitamins include eight vitamins, each with its own special function. They all help the body use fats, proteins and carbohydrates for energy. Deficiencies in B vitamins can cause forgetfulness, depression, irritability and damage to the digestive tract. B vitamins are present in many healthy, whole and non-processed foods; thus, a diet lacking in B vitamins is likely to be deficient in other nutrients as well. Good vitamin B sources include meats, unrefined grains, beans, potatoes and molasses.

Vitamin C

Vitamin C is a potent antioxidant, a substance that helps protect the body from the effects of free radicals, which are unstable molecules that latch onto cells and damage them. According to the Harvard School of Public Health, vitamin C is also necessary for the synthesis of collagen, a key building block of tendons, ligaments and skin. Bruising, frequent infections and problems with wound healing can result from a deficiency in vitamin C. Citrus fruit, berries, red peppers and tomatoes are all good sources of this vitamin.

Vitamin D

Vitamin D is important for bone health and immune system functioning. It may also play a role in preventing cancer and heart disease, according to the Harvard School of Public Health. Vitamin D is unlike other vitamins in that it is synthesized in your body during exposure to sunlight. Many people do not get enough sun exposure for adequate vitamin D synthesis. Dietary sources include fatty fish, eggs, fortified milk and fortified orange juice.

Vitamin E

Vitamin E has many physiological functions. A potent antioxidant, this vitamin is necessary for normal brain functioning, wound repair and blood vessel health. Overt vitamin E deficiencies are virtually unheard of in otherwise healthy people who do not get much vitamin E in their diets. Good dietary sources include wheat germ, almonds, sunflower oil, safflower oil and peanut butter.

Vitamin K

The principal role of vitamin K is to assist with normal blood clotting. The vitamin plays such a central role in clotting that surgeons often administer it during surgery to reduce excess bleeding. Your intestines can synthesize vitamin K; you can also obtain it from food sources such as spinach, lettuce, broccoli and other green vegetables. Vitamin K deficiencies are rare, but they can occur in newborns and people who have problems with bile production and in conditions in which antibiotics have killed off the healthy bacteria in your digestive tract.