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Are Dietary Supplements Necessary for Good Health?


Updated July 08, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

dietary supplements in palm of hand

There are so many dietary supplements available and you don't need all of them.

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Weight Loss Supplement

Be safe. Follow dietary supplement label directions.

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broccoli or vitamins

Don't choose between foods or supplements. Following a healthy diet is the top priority.


Eating a healthy, well-balanced diet should provide you with all of the individual nutrients you need, but if your diet isn't so good, some of those nutrients might be deficient. For example, a person who hates fruits and vegetables might not get enough vitamin C and someone who refuses to eat dairy products may need extra calcium.

Taking a daily multivitamin is an inexpensive and easy way to be sure you are getting the vitamins and minerals you need. A few individual dietary supplements have been shown to have positive benefits for your health too. Adding these extra supplements may be beneficial:

Calcium: Many people don't eat enough calcium-containing foods. This can add to a person's risk of developing osteoporosis, or weakened bones. The recommended amount of calcium for most adults is about 1,200 milligrams per day.

Vitamin D: Some of the vitamin D you need comes from the food you eat, but most of it's made by your body after exposure to sunlight. Vitamin D is important for calcium absorption and the two nutrients are often combined into one supplement. An average adult needs about 400 International Units of vitamin D. Supplements may help, but you'll probably need to do more than take supplements to prevent bone fractures

Fish Oil: Omega-3 fatty acids will help prevent cardiovascular disease. Fatty fish is the best dietary source of omega-3 fatty acids, though plants such as flax contain omega-3 fatty acids. Studies suggest that 0.5 to 1.8 grams of fish oil per day is an effective amount.

Folic Acid: Folate is a natural B vitamin, and folic acid is the synthetic form. Folate is found in green leafy vegetables, citrus fruit and legumes. Folic acid supplements are recommended for any woman who may become pregnant and may also help reduce homocysteine levels, which might help reduce the risk of heart disease. The recommended amount for adults is 400 micrograms per day.

Chondroitin and Glucosamine: Researchers from the Glucosamine/Chondroitin Arthritis Intervention Trial found that participants with moderate-to-severe osteoarthritis pain found statistically significant amounts of pain relief with 1,500 milligrams glucosamine combined with 1,200 milligrams chondroitin sulfate supplements.

Antioxidants and Zinc: The Age-Related Eye Disease Study results showed that a combination of antioxidants and zinc taken as a dietary supplement reduced the risk of advanced age-related macular degeneration. The formula used in the study was:

  • 500 milligrams vitamin C
  • 400 International Units vitamin E
  • 15 milligrams beta-carotene
  • 80 milligrams zinc as zinc oxide
  • 2.0 milligrams copper as cupric oxide
Zinc is an important dietary mineral, but taking too much supplemental zinc might lead to zinc toxicity.

Probiotics: Foods like yogurt and fermented foods naturally contain bacteria called probiotics. These bacteria are similar to the friendly bacteria normally found in your digestive system. Probiotics are also available as dietary supplements and may be beneficial for people with irritable bowel syndrome and diarrhea.

Dietary Supplement Safety: In general, dietary supplements are safe. However keep these points in mind when you take them:

  • Eat a healthy diet. Multivitamins and other dietary supplements will not replace an unhealthy diet. Focus on eating sufficient amounts of fruits and vegetables, low-fat dairy products, whole grains, lean meats, fish, poultry, nuts, seeds and legumes.
  • Don't overdose your supplements. Some vitamins such as vitamin D, vitamin A and vitamin B-6 can be bad for your health when taken in extremely large amounts for extended periods of time.
  • Follow the dosage instruction on the label. 
  • Know which supplements should be taken on an empty stomach.
  • Tell your doctor. Some dietary supplements can interact with medications, so tell your doctor about the dietary supplements you take.
  • Understand the label. Dietary supplement labels can make claims about how the dietary supplement may affect the structure or the function of the body, but not claims to treat or cure a disease.
  • Know how dietary supplements are regulated and if they are standardized
  • Supplements have both potential risks and possible benefits
  • Supplements taken in large amounts may cause uncomfortable side effects. Large doses of iron may cause constipation and large amounts of niacin might cause a niacin flush.

More About Labels and Health Claims

The labels on dietary supplements can be very confusing. Supplement manufacturers can make health claims if they are approved by the FDA. One example would be "adequate folic acid may reduce a woman's risk of having a child with a neural tube defect." Label claims may not promise cures, or guarantee that taking their supplement will prevent any disease.


American Heart Association. "Fish and Omega-3 Fatty Acids." Accessed January 2011. http://www.americanheart.org/presenter.jhtml?identifier=4632."

Harvard School of Public Health. "Vitamins." 2007.

Huang HY, Caballero B, Chang S, Alberg A, Semba R, Schneyer C, Wilson RF, Cheng TY, Prokopowicz G, Barnes GJ 2nd, Vassy J, Bass EB. "Multivitamin/Mineral supplements and prevention of chronic disease." Evid Rep Technol Assess (Full Rep). 2006 May;(139):1-117.

National Center for Complimentary and Alternative Medicine. "Questions and Answers: NIH Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)." National Institutes of Health. Updated April 2007.

National Eye Institute. "Age-Related Eye Disease Study--Results." National Institutes of Health. Updated May 2007.

National Center for Complimentary and Alternative Medicine. "An introduction to probiotics." National Institutes of Health. Updated January 2007.

Office of Dietary Supplements. "Dietary Supplement Fact Sheet: Calcium." National Institutes of Health. Updated September 2005.

Office of Dietary Supplements. "Dietary Supplement Fact Sheet: Folate." National Institutes of Health. Updated August 2005.


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