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Nutritional Supplement Overview:

Dietary supplements, or nutritional supplements, are substances you might use to add nutrients to your diet or to lower your risk of health problems.  While foods are typical sources of supplements, synthetics can also be used.  Supplements come in the form of pills, capsules, powders, liquids, or bars. They include vitamins, minerals, herbs and many specialty products (“VMHS”).  Actually, you don’t need a doctor’s prescription to buy dietary supplements.

Eating a variety of healthy foods is the best way to get the nutrients you need. However, some people don’t get enough vitamins and minerals from their daily diet, or they have deficiencies in certain substances due to poor lifestyle, such as lack of regular exercise, insufficient exposure to sunshine during winter time, over drinking, etc. In these cases, they may need a supplement.

Scientific evidence shows that some dietary supplements are beneficial for overall health and for managing some health conditions. For example, calcium and vitamin D are important for keeping bones strong and reducing bone loss; folic acid or folate decreases the risk of certain birth defects; and omega-3 fatty acids from fish oils might help some people with heart disease. Other supplements need more study to determine their value. As a matter of fact, the majority of adults in the United States take one or more dietary supplements either every day or occasionally.

How each country defines supplements differently?

United States:

All products labeled as a dietary supplement carry a Supplement Facts panel.  This panel lists the contents, amount of active ingredients per serving, and other added ingredients (like fillers, binders, and flavorings). The manufacturer suggests the serving size, but you or your healthcare provider might decide that a different amount is more appropriate for you. The Dietary Supplement Health and Education Act of 1994 (DSHEA) defines the term “dietary supplement”. Since dietary ingredients are substances already available in the diet, they are considered food and are treated as such, not as drugs or food additives. 


The term “health food” (Bao Jian Ping) is similar to dietary supplements in the U.S. but carries a different definition.  China defines health food as food product that have specific health functions or supply vitamins and (or) minerals, suitable for specific groups of people but not for the purpose of curing.

Other countries:

Most countries regulate supplements industry, but do not always consider supplements as food products and could treat them as drugs, depending on the claims stated in marketing or on the label. The European Union defines supplements as foodstuffs to supplement the normal diet, but have a nutritional or physiological effect.  The Canadians call it natural health product. In Australia, they use the term complementary medicines, while in Japan, food with health claims (FHC).

In this nutritional supplement overview, and throughout this website, we adopt the U.S. definition of dietary or nutritional supplements. Our website is developed and maintained by a group of US-based nutritional scientists, healthcare practitioners and experts who have worked in the supplements industry for decades. As a matter of fact, we source a vast majority of health information directly from the National Institute of Health ( NIH has a number of branches dedicated to medical and supplement research. From NIH’s website, you also have access to Office of Dietary Supplements (ODS), National Center for Biotechnology Information(NCBI), National Center of Complementary and Integrative Medicine (NCCIM), National Library of Medicine(NLM), as well as open, authoritative databases such as PubMed, PubChem and MedlinePlus.


Dietary supplements are complex products. The FDA has established good manufacturing practices (GMPs) for dietary supplements to help ensure their identity, purity, strength, and composition. Overall, the purposes of GMPs are to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. To enforce the GMPs, the FDA periodically inspects facilities that manufacture dietary supplements.

In addition, several independent organizations offer quality testing and allow products that pass these tests to display their seals of approval. These seals of approval provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. However, these seals of approval do not guarantee that a product is safe or effective. Organizations that offer this quality testing include:

  • U.S. Pharmacopeia
  • NSF International

Our nutritional supplement overview provides a list of top brands recommended by

Should I use supplements?

If you are thinking about using dietary supplements, please keep the following in mind:

Learn and educate yourself

Find out as much as you can about any dietary supplement you might take. If possible, talk to your doctor, your pharmacist, or a registered dietitian. A supplement that seems to help your neighbor might not work for you. If you are reading fact sheets or checking websites, be aware of the source of the information. For your convenience, we list all major ingredients here.

Beware of side effects

A vast majority of supplements are safe. However, just because something is said to be “natural” doesn’t mean it is safe or good for you. It could have side effects. Be aware that some supplements might make another medicine weaker or stronger. A supplement could also be harmful to you if you have certain medical conditions.

Buy wisely

Choose brands that your doctor, dietitian, or pharmacist recommend. Don’t buy dietary supplements with ingredients you don’t need. Don’t assume that more is better. Otherwise, it is possible to waste money on unneeded supplements. Visit Buyers’ Guide.

Check the science

Make sure any claim about a dietary supplement is based on scientific proof. Generally speaking, the company making the dietary supplement should be able to send you information on the safety and/or effectiveness of the ingredients in a product. Remember, if something sounds too good to be true, it probably is.

What is the “best” supplement? The answer is: there is none. Stick to a healthy diet, be physically active, be optimistic, don’t smoke, and, in most cases, only use dietary supplements suggested by your doctor or pharmacist. However, if you don’t have easy access to a doctor who is well trained in nutritional science, please visit this website and its nutritional supplement overview.

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