Vitamins

Definition

Contrary to minerals, vitamins are organic compounds, which can be found in plants and animal foods. Thirteen different vitamins are known to be necessary to human beings in order for them to stay healthy. Most of these (except vitamin D and K) are not made in the human body, and must therefore be obtained from either food or supplements.

Purpose

Each of these 13 vitamins have specific functions and have roles in almost every process in the human body. They aid blood clotting, vision, reproduction and conversion of food to energy among other functions.

Description

Water-soluble vitamins

People require 9 water-soluble vitamins. They are called that because they dissolve in water and are thus not stored for long periods of time. Here is a list of these vitamins:

1. Vitamin B₁ (thiamin): required for the conversion of carbohydrates to energy

1. Vitamin B₂ (riboflavin): aids in breaking down fats, carbohydrates and proteins and increases the bioavailability of other vitamins and minerals
2. Vitamin B₃ (niacin): helps process fats and proteins
3. Vitamin B₅ (pantothenic acid): aids in chemical reactions that produce energy
4. Vitamin B₆ (pyridoxine): associated with the transmission of nerve impulses, formation and functioning of red blood cells, and creation of new cells
5. Vitamin B₁₂ (cobalamin): required for maintenance of red blood cells, creation of new DNA, and maintenance of nerve cells
6. Vitamin C (ascorbic acid): aids in the formation of cartilage and connective tissue, protects cells from free radical damage
7. Vitamin H (biotin): joins with enzymes that regulate the breakdown of foods and their use in the body
8. Folic acid (folate): helps make new cells; important in development of the fetal nervous system

Fat-soluble vitamins

People require 4 fat-soluble vitamins, which, unlike those that dissolve in water, can be stored in the body. High doses of these cause health problems. Here is a list:

1. Vitamin A (retinol, retinal, carotenoids): helps vision, reproduction, and works as a growth factor for epithelial and other cells
2. Vitamin D (ergocalciferol, cholecalciferol): helps immune system, controls mineralization
3. Vitamin E (tocopherols, tocotrienols): protects cells from free radical damage, aids nerve conduction
4. Vitamin K (phylloquinone, menaquinones): aids blood clotting

Vitamin supplements

Vitamin supplements come in many forms, including tablets, capsules, and liquid form. They may contain a single vitamin, a group of related vitamins, a mixture of vitamins and minerals, or they may be multivitamins, containing a little of everything. According to research, only around half the multivitamins brands contain what they claim to contain, so consumers are advised to read the label carefully, avoid large doses, and stick with well-known brands.

Vitamin requirements

Generally, people who eat a lot of fruit, vegetables, and  whole-grain get the vitamins they require without having to take multivitamins. Many, however, choose to take multivitamins as a precaution. This is not really recommended, except to some groups of people, who have an increased need:

• the elderly
• vegans
• breastfed babies of vegan mothers
• people who do not eat dairy products
• alcoholics
• people who have had part of their stomachs or intestines surgically removed
• pregnant women or pregnant-to-be women
• people with diseases that interfere with vitamin metabolism
• people taking drugs that interfere with vitamin metabolism