Health Encyclopedia

Vitamin Supplement Advice

When do you need a vitamin supplement? According to researchers at the Harvard School of Public Health, a daily multivitamin may be a good idea for most adults.

That's not to say you should abandon good nutrition in your daily diet. If you eat a varied diet with lots of fruits and vegetables, you're likely to get all the vitamins and minerals that you need.

If you take a dietary supplement that focuses just on one or two nutrients, you may end up with too much of those nutrients, interfering with the absorption of other vitamins.

What are vitamins and minerals?

Vitamins are complex organic micronutrients, which is a fancy way of saying that they work at the microscopic level to help your body carry out complex chemical processes. They have no calories themselves, and with a few exceptions, they're not manufactured inside your body. Some vitamins help in biochemical transformations, such as the absorption of oxygen in the lungs. Others act as antioxidants, protecting tissues from disease-causing damage and premature aging.

Minerals are naturally occurring inorganic elements your body needs to function. Minerals allow the body to build certain structures and help trigger some bodily reactions. Iron, for example, is a key to the production of hemoglobin, an important protein in the red blood cells. Calcium is used to build bone and tissues. Zinc is essential for nerve transmission. Compared with vitamins, minerals have a very simple molecular structure. And unlike some vitamins, cooking does not destroy their essential nutrients.

Vitamin details

Here's a look at some of the important vitamins:

  • Vitamin A. This vitamin is important for vision and helps you see in the dark. Harvard researchers say it helps with the production of white blood cells, is important in bone health, and regulates cell growth. The current recommended intake of vitamin A is 900 micrograms (mcg) for men and 700 mcg for women. Fortified breakfast cereals, juices, and dairy products, as well as many fruits and vegetables, contain vitamin A.

  • B vitamins. Folic acid plays a key role in preventing birth defects. Folic acid and other B vitamins may play a role in preventing heart disease and stroke. The recommended daily intake of folic acid is 400 mcg; folic acid is found in dark green leafy vegetables, fortified breakfast cereals and grains, and beans. Vitamin B6: 1.3 to 1.7 mg daily. Vitamin B12: 2.4 to 2.8 mcg daily. While research continues to look at the effect of B vitamins on lowering heart disease risk, so far no studies have concluded that B vitamins are effective in this manner. In addition, the American Heart Association does not recommend using folic acid or vitamin B supplements to prevent heart disease or stroke.

  • Vitamin C. Vitamin C helps control infections, and is also necessary for bone, teeth, gums, and blood vessel health. The current recommended daily intake is 90 mg for men and 75 mg for women. Vitamin C is found in citrus fruits and juices, berries, bell peppers, tomatoes, broccoli, potatoes, and spinach.

  • Vitamin D. This vitamin is important for bone health, but many Americans don't get enough vitamin D. Spending some time in the sun each day helps your body manufacture vitamin D. The requirement for this vitamin is 10 to 15 mcg up to age 50, 15 mcg from age 51 to age 70, and 20 mcg after age 70. Good sources of vitamin D are fortified dairy products and breakfast cereals, and salmon, tuna, and other fatty fish.

People in need

While most vitamins and minerals can be obtained through a well-balanced diet, some people can benefit from taking a supplement in addition to a healthy diet, however. According to the American Dietetic Association, a vitamin supplement may be helpful if you fit any of the following profiles:

  • You frequently skip meals or don't eat enough fruits, vegetables, grain, and dairy products.

  • You're on a low-calorie diet.

  • You're a strict vegetarian.

  • You can't drink milk or eat yogurt.

  • You're a woman of childbearing age and don't eat fruits and vegetables.

  • You are pregnant.

If you believe you should take vitamin supplements, talk with your doctor or dietitian to make sure you are taking the correct amount and that the supplements are not causing an interaction with other medications you take or any conditions you may have.



Medical Reviewers:

  • McClintock, Heidi, RD, LD