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What are vitamins?

Vitamins are chemicals your body needs in tiny amounts to keep you healthy. For example, you have probably heard of vitamins A, B, C, D, E, and K. You get vitamins from food, and some are made by the body.

Some diseases are caused by a lack of vitamins. Fruit and vegetables provide vitamins and can help prevent these diseases. Scurvy is an example of one of these diseases. More than 200 years ago, it was found that scurvy could be prevented on long sea voyages by giving sailors citrus fruit each day. Citrus fruit is a source of vitamin C.

A healthy diet is the best way to get the nutrition you need. However, you may improve your health and lower some risks by taking a vitamin or mineral supplement if:

  • You have a health condition that keeps your body from absorbing nutrients.
  • You have a health condition that requires a special diet.
  • You don’t have a healthy diet because you don’t eat enough food. Or you don’t eat enough different types of foods.
  • You are a woman of child-bearing age. If you become pregnant, it may be hard for you to get enough of some of the nutrients your baby needs.
  • You are 65 or older.
  • You are a woman who has been through menopause and you want some protection against osteoporosis.
  • You are taking certain medicines or abusing alcohol or narcotics.

Taking a daily multivitamin-and-mineral supplement may be a sensible precaution to help avoid nutrient deficiencies in older adults. It should be noted, however, that as a person ages, it takes the liver longer to get rid of drugs and vitamins in the body. This may increase their effects. Dosage levels that might be harmless in a younger adult could be poisonous for an older adult.

Follow these basic guidelines if you take supplements:

  • Avoid a dosage that is too high. Choose a multivitamin supplement that gives about 100% of the daily value for your age.
  • Be sure the product is a well-known, trusted brand. Check for a label that shows approval by the US Pharmacopeia (USP),, or NSF.
  • Store all vitamins in a cool, dry place.
  • Check with your healthcare provider, pharmacist, or dietitian before you start taking supplements. This is especially important if you take prescription medicine or are being treated for a health problem.

Why is vitamin A important?

Vitamin A is needed for growth and for strong bones and teeth. As you grow older, it helps keep your skin and eyes healthy. Vitamin A is in liver, fish liver oils, dairy products, dark green and yellow-orange vegetables, and in fruits.

Too much vitamin A can be poisonous. It may cause symptoms that include headache, itchy skin, and hair loss. It is rare to get too much vitamin A from foods, but taking supplements with dosages that are higher than recommended can cause long-term health problems.

What does vitamin B do for me?

Several vitamins are in the B group. They play a part in many of the processes that make our bodies work properly. They are especially needed for changing our food to energy and keeping our blood healthy. Vitamins in the B group are in meats, dairy products, nuts, grains, leafy vegetables, and some fruits.

If you are 50 or older, eat foods fortified with vitamin B12 or take a dietary supplement that contains vitamin B12.

No poisonous effects have been found for most B vitamins. However, too much vitamin B6 can irritate the nerves.

Why do I need vitamin C?

Vitamin C helps build healthy tissues. It also helps your body heal and may help boost the immune system. It is also an antioxidant, which means it protects against damaging chemical processes in the body. Vitamin C is found in fruit (especially citrus fruit and cantaloupes) and vegetables, such as tomatoes, potatoes, and green peppers.

Taking high doses of Vitamin C supplements can cause diarrhea. It can also thin blood too much, especially if you are taking a blood thinning medicine. It can increase the risk for kidney stones.

What about vitamin D?

Vitamin D builds strong bones and teeth and helps prevent osteoporosis as you grow older. Vitamin D is in fortified dairy products (mainly milk), oily fish, liver, and egg yolk. Sunlight is another source of vitamin D.

Too much vitamin D can cause digestive upsets, depression, and calcium deposits in the kidneys and blood vessels.

Why should I take vitamin E?

Vitamin E is an antioxidant vitamin that helps the cells in your body stay healthy. It also helps your body make new red blood cells. It is in nuts, seeds, plant oils, avocados, grains, and egg yolk.

Too much vitamin E can upset your stomach and cause bleeding, especially if you are taking a blood thinning medicine.

Why is vitamin K important?

Vitamin K is needed to help your blood clot after an injury. You also need it to keep your bones healthy and to help you heal if you have a broken bone. It is found in leafy green vegetables, broccoli, vegetable oils (especially canola and soybean), egg yolk, pork, and liver. Vitamin K is also made by bacteria that live in your gut.

Large doses of vitamin K can cause allergic reactions in some people, such as itching and rash. If you are taking blood-thinning medicine, your healthcare provider will tell you how much vitamin K you can have.

Why is folic acid important?

Women of child-bearing age should take a daily folic acid supplement of 400 to 800 micrograms (mcg, or ug). Taking folic acid supplements at least 1 month before you get pregnant and then during pregnancy helps protect the baby against problems with the spinal cord. Because not all pregnancies are planned, this daily supplement is recommended for all women of child-bearing age.

Developed by Ann Carter, MD, for RelayHealth.
Published by RelayHealth.
Last modified: 2011-04-20
Last reviewed: 2011-04-18
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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