Who takes vitamins?

It is estimated that about half of American adults take some type of vitamin or mineral supplement. These supplements are widely available, with each reported to have certain health benefits. Choosing which type to take can be a challenge.

Everyone’s vitamin needs are different, so it is good to talk to your doctor or registered dietitian before starting to take supplements. Your doctor can help you decide which products to take, or if you need to take any at all. Your doctor and pharmacist can also tell you if a supplement would interact badly with any medications you are taking, which may cause health problems.

This basic guide will help you understand the benefits and the recommended daily amounts for vitamins, as well as for the important minerals iron, calcium, and zinc.

The recommended daily allowance (RDA) for vitamins and minerals is the average daily intake a person needs to avoid vitamin deficiencies and stay healthy. Men and women often have different vitamin and mineral recommendations.

There are different ways to measure the RDA. Vitamins and minerals that are needed in larger doses are measured in milligrams (mg) and those that the body needs less of are measured in micrograms (mcg). There are 1,000 mcg in 1 mg. Each vitamin and mineral has a specific RDA.

Vitamin A

Vitamin A is fat-soluble vitamin also known as retinol. The RDA of vitamin A is 700 mcg for women and 900 mcg for men. Vitamin A can be found in many dairy products and yellow- or orange-colored fruits and vegetables.

Vitamin A benefits:

  • Helps fight infection
  • Maintains healthy vision
  • Plays a key role in heart, lung, and kidney health
  • Keeps skin healthy by fighting off toxins (also called free radicals)
  • Strengthens bones and teeth

Vitamin B

There are eight B vitamins, known as the B-vitamin complexes, with varying RDAs. According to the United States Department of Agriculture (USDA), most Americans do not get their RDA of B vitamins in their daily nutrition. In the U.S., many cereals, flour, breads, and pasta are routinely fortified with B vitamins to minimize risk of deficiency. B vitamins can be found in leafy green vegetables, animal proteins, and whole grains.

Vitamin B benefits:

  • Maintains normal brain function and memory
  • Needed for normal metabolism of carbohydrate, protein, and fats
  • Improves cholesterol by lowering LDL (bad cholesterol) and increasing HDL (good cholesterol)
  • Reduces risk of heart disease
  • Reduces risk of stroke
  • Necessary for normal blood cell production and nervous system function

Vitamin C

Vitamin C is a water-soluble vitamin containing antioxidants that promote healthy tissue growth. The RDA for men is 90 mg and 75 mg for women. Vitamin C can be found in many fruits and vegetables.

Vitamin C benefits:

  • May reduce risk of getting the common cold
  • Maintains skin and tissue health
  • Strengthens bones and teeth

Vitamin D

Vitamin D is an essential fat-soluble vitamin that is activated by ultraviolet (UV) light. Vitamin D can also be found in cod liver oil, fatty fish, fortified juices, milk, and cereals. These can be a healthy alternative when a person does not get enough UV light. For children and adults the RDA is 15 mcg (600 IU). For ages 70 and older it is 20 mcg (800 IU).

Vitamin D benefits:

  • Influences immune cell function
  • Maintains nervous system functions
  • Needed for bone health
  • Regulates blood levels of calcium and phosphorus

Vitamin E

Vitamin E is an important vitamin for organ function. Fifteen (15) mg should be consumed daily. Sources of vitamin E include vegetable oils, avocados, spinach, seeds and nuts, and whole grains.

Vitamin E benefits:

  • Protects cells from damage from toxins
  • Maintains muscle function
  • Reduces risk of cancer
  • Reduces risk of heart disease
  • Reduces risk of Alzheimer’s

Vitamin K

Vitamin K is essential for blood clotting. The RDA of vitamin K is 120 mcg for men and 90 mcg for women. This protein-rich vitamin is mainly found in leafy green vegetables.

Vitamin K benefits:

  • Helps in rapid wound healing
  • Creates strong bones
  • Helps protect against heart disease


Calcium is a mineral needed for healthy bone growth. The RDA of calcium is 1,000 mg for men and women ages 19 to 51; for women 51 and older and for men older than 70 it increases to 1200 mg per day. Most dairy products, such as milk, cheese, and yogurt, are good sources of calcium. Tofu, spinach, soy, and rhubarb are also high in calcium.

Benefits of calcium:

  • Improves muscle function
  • Helps to achieve healthy blood pressure
  • Aids in hormone secretion
  • Helps maintain strong bones
  • Helps maintain strong teeth
  • Decreases risk of osteoporosis


Iron helps transport oxygen in blood. Not enough iron may result in a weak immune system and fatigue. Men and women should consume between 8 and 18 mg of iron daily. Iron is found in red meats, leafy green vegetables, and legumes.

Benefits of iron:

  • Improves immune function
  • Provides energy
  • Improves brain function
  • Improves ability to concentrate
  • Carries oxygen in blood


Zinc is only needed in small amounts. RDA for men is 11 mg and 8 mg for women. Red meat and poultry are good sources of zinc.

Benefits of zinc:

  • Reduces risk of cancer
  • Improves immune system
  • Improves memory
  • Reduces common cold symptoms

Last reviewed by a Cleveland Clinic medical professional on 07/27/2015.


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