Vitamin and mineral requirements in human nutrition, 2nd ed. World Health Organization, Vitamins and minerals.
Vitaminsand minerals are micronutrients that the body needs to perform a number of normal functions. However, these micronutrients are not produced in our body and must be derived from the food we eat.
Most people should be able to get all the nutrients they need with a varied and balanced diet. If you decide to take vitamin and mineral supplements, seek advice when appropriate. The Institute of Medicine has determined the upper limits for 24 nutrients. This table is for adults over 19 years old.
It does not apply to women who are pregnant or breastfeeding, because they have different nutritional needs. Vegans (vegetarians who don't eat any animal products, including dairy products) may need to take vitamin B12 supplements. Soon after, researchers determined the specific amounts of vitamins needed to prevent diseases caused by deficiency.
Water-soluble vitamins(vitamin C and B vitamins, such as vitamin B6, vitamin B12, and folate) must be dissolved in water before they can be absorbed by the body and therefore cannot be stored.
Vitamin D helps regulate the amount of calcium and phosphate in the body, which is important for healthy bones, teeth and muscles. Some population groups (with little or no exposure to sunlight) don't get enough vitamin D from sunlight and are at greater risk of vitamin D deficiency. If you're vegan, you should consider taking a vitamin B supplement to reduce your risk of developing vitamin B12 deficiency anemia. With lots of vitamins and minerals, you can safely take a much higher dose than the RDA or DV without going anywhere near the UL.
That number is the amount of a vitamin or nutrient you must get for good health on a 2,000-calorie-a-day diet. The RDA (recommended daily amount) and the IA (adequate intake) are the amounts of a vitamin or mineral that are needed to stay healthy and well nourished. If you don't eat meat, you can get vitamin B12 from eggs, milk and other dairy products, and from fortified breakfast cereals.
Fat-soluble vitamins(vitamin A, vitamin D, vitamin E, and vitamin K) dissolve in fat and tend to accumulate in the body.
Multivitamins can play an important role when nutritional needs are not met by diet alone.