Vitamins and minerals are nothing short of essential. They help produce energy, fight disease and repair injured tissue. One of their most vital functions is to activate enzymes that initiate and control chemical reactions in the body.
Although vitamin and mineral deficiencies are rare in the United States, less-than-optimal intakes of certain nutrients are common among Americans. If you don’t get what you need you raise your risk of chronic illnesses, including cardiovascular disease, colon cancer, and bone fractures.
Two groups of vitamins
There are 13 essential vitamins. They are divided into two major groups: water soluble (vitamin C and the B vitamins, which dissolve in water and are eliminated in the urine) and fat soluble (vitamins A, D, E and K, which are absorbed by the body with the help of fat or bile and stored in fat and liver cells). With the exception of vitamin B12, water-soluble vitamins cannot be stored in the body for long periods of time and need to be replaced frequently. Fat-soluble vitamins have more staying power and require less frequent replacement.
Two groups of minerals
Minerals can also be divided into two groups—macrominerals and microminerals. Macrominerals include calcium, phosphorus, chloride, sodium, magnesium and potassium, which are present in the body in large amounts. Microminerals include chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium and zinc, present in smaller amounts but no less important).
Most people are able to meet their nutritional needs by eating a variety of nutrient-packed foods. Although a 2013 study in JAMA suggested that a daily multivitamin may modestly reduce cancer risk in men, there is little evidence that the average person benefits from daily use.
On the other hand, if your food intake is limited—perhaps because you’re on a low-calorie diet or your appetite isn’t what it used to be—discuss with your doctor whether you should take a multivitamin-mineral supplement to help to fill nutritional gaps. Keep in mind that a supplement is not a substitute for eating a balanced diet rich in unprocessed whole foods that are naturally full of thousands of potentially health promoting substances.
If you do decide to take a multivitamin supplement, never take more than one a day unless recommended by your doctor. Taking more than needed may actually increase your risk of health problems.
Most multivitamin-mineral supplements contain the recommended dietary allowance (RDA) of all the essential vitamins and a number of key minerals. Most men and postmenopausal women should select a multivitamin-mineral supplement that contains little or no iron because they do not need extra iron. Products formulated especially for older adults typically contain less iron and vitamin A and more calcium, vitamin B12 and vitamin B6 than those for younger adults.
While the amounts of vitamins and minerals in multivitamins are generally safe, high doses of some nutrients (particularly fat-soluble vitamins) are dangerous. A notable example is the toxic effect of excessive amounts of vitamin A. To avoid this problem, choose a supplement that contains no more than 3,000 international units (IU) of vitamin A with at least 20 percent of the vitamin A in the form of beta-carotene. Also avoid certain vitamin A supplements such as cod liver oil.
Our advice: Take multivitamin-mineral supplements with food because the nutrients in the supplements are best absorbed with other nutrients. To avoid the expense of name-brand vitamins, buy generic-brand multivitamins sold at pharmacies, grocery stores or discount shops.