Dietary Supplements:

What are dietary supplements?

The Dietary Supplement Health and Education Act (DSHEA) defines a dietary supplement as a product that:

• supplements the food you eat;
• contains one or more dietary ingredient (including vitamins; minerals; herbs or other botanicals; amino acids, and other substances);
• comes in pill, capsule, tablet, or liquid form; and
• is labeled as a dietary supplement.

There are different types of dietary, or nutritional, supplements. Vitamin and mineral supplements are types of dietary supplements containing micronutrients meant to help a healthy body function smoothly. Herbal (or botanical) supplements are dietary supplements that have a medicinal purpose. Herbal supplements generally support a specific area of the body’s health, such as the liver, bones or skin.

Health benefits of vitamin and mineral supplements

Vitamins and minerals are micronutrients that serve a specific purpose and benefit the body in a unique way. For example, vitamin A supports vision and bone growth, whereas vitamin E strengthens the immune system and helps repair DNA. Vitamin and mineral deficiency can impair the body’s ability to heal and protect itself.

Taking vitamins does not make up for an unhealthy diet, and vitamins are an insufficient substitute for nutrients from fresh fruits, vegetables and whole grains, but a general multivitamin and mineral supplement can be a good safeguard.

Herbal Supplements

Herbal supplements are different from vitamin and mineral supplements in that they are considered to have medicinal value. Herbs, also known as botanicals, are one of humanity's oldest health care tools, and the basis of many modern medicines. Primitive and ancient civilizations relied on herbs for healing, as do contemporary cultures throughout the world. In fact, the World Health Organization has estimated that 80% of the world's population continues to use traditional therapies, a major part of which are derived from plants.

If you are taking other medications, refrain from taking herbal supplements without first checking with your doctor. Herbal supplements and over-the-counter medications or prescription drugs can combine to cause adverse side effects.  Just because an herbal supplement is extracted from a “natural” source does not render it any less potent than any other chemicals you may ingest. 

Who can benefit from vitamin and mineral supplements?

In general, children and adults might benefit from taking one multivitamin per day. A multivitamin helps provide a consistent source of the necessary vitamins and micronutrients. According to the Harvard School of Public Health, "a daily multivitamin, and maybe an extra vitamin D supplement, is a great way to make sure you’re getting all the nutrients you need to be healthy."

However, the very first consideration is to eat a healthy diet. Even the best supplement is no substitute for good nutrition. In general most Americans consume foods that are high in calories, but lack nutrients that are vital for good health.

Some groups of people, because of distinct nutritional needs, especially benefit from taking a vitamin and mineral supplement:

• Women of childbearing age (need extra calcium and iron)
• Pregnant or lactating women
• Children and teenagers with irregular eating habits
• Seniors
• Vegetarians or vegans (may be deficient in key nutrients)
• Dieters or people avoiding certain food groups (may be deficient in key nutrients)
• People with eating disorders or medical conditions (deficiency diseases, absorption problems, lactose intolerance, etc.)
• People who eat processed and fast food often

Ensuring smart supplementation

The word “supplement” means something added. In this case, you’re “adding” to a basic healthy diet and lifestyle, or a prescription medication or therapy you’ve been given to treat a condition or disease. An herbal supplement or vitamin regiment on its own will not necessarily cure or treat your condition or heath problem. And remember that not all supplements are good, especially when taken in toxic doses or combined with other medications.

The media loves exciting headlines, so the moment an herb or vitamin is tentatively shown to be beneficial in some way, it is touted as the next miracle cure. Advertising can be misleading as well, promising us “totally safe”, “natural” and “quick and effective” solutions to many health problems. You can keep yourself from falling prey to false promises by researching any product you are considering taking. Make sure there is good scientific research that supports the claims of the supplement’s marketers.

Supplement safety

Dietary supplements may not be risk-free under certain circumstances. Be sure to consult your health practitioner before purchasing or taking any supplement if you are pregnant, nursing a baby, or have a chronic medical condition such as, diabetes, hypertension or heart disease. Also, while vitamin and mineral supplements are generally considered safe for children, you may wish to check with your doctor before giving these or any other dietary supplements to your child.

The 1994 Dietary Supplement Health and Education Act made it possible for dietary supplements and homeopathic remedies to be marketed without providing evidence of safety or efficacy before the FDA. In order for a product to get removed from the shelves, the F.D.A must prove that it is dangerous – and that is often to the detriment of the consumer.

Supplement manufacturers are allowed to make claims regarding health, nutritional content and structure/function subject to limited restrictions. Health claims describe a relationship between a food, food component, or dietary supplement ingredient, and reducing risk of a disease or health-related condition. For example: "Provides relief from symptoms associated with PMS and menopause such as cramps, hot flashes, breast tenderness and moodiness" on a bottle of Evening Primrose Oil capsules.

Nutrient content claims refer to the percentage of DV (daily value) of the nutrient the supplement provides. A structure/function claim is a statement describing how a product may affect the organs or systems of the body. It can't mention a specific disease. For example: "COQ10 supports heart function as a component of the electron transport system, and as an antioxidant protects mitochondrial membranes and cholesterol from oxidation."

When selecting a nutritional, dietary, or herbal supplement, keep in mind the following:

• Nutritional, dietary, and herbal supplement manufactures are not are required to run studies to determine product safety or efficacy
• The FDA does not analyze the contents of dietary supplements
• Dietary supplement manufacturers must meet the FDA’s Good Manufacturing Practices (GMP) for food, but some companies also follow the GMP for drugs on a voluntary basis.
• Specific health claims on dietary supplement labels are not approved by the FDA and must also include a disclaimer that states the nutritional supplement is not intended to “diagnose, treat, cure, or prevent any disease.”
• Daily Value (DV) describes the recommended daily intake of a particular nutritional supplement, if one is established

In addition, keep in mind the following safety concerns when taking vitamin or mineral supplements:

Don't substitute supplements for medication

If you’re considering using a dietary supplement in place of drugs, consult your health care provider first. And remember, just because it is “natural” doesn’t mean its gentler or more beneficial to your body - many supplements contain active ingredients that have strong biological effects and their safety is not assured.

Some supplements can have unwanted effects during surgery

You may be asked to stop taking certain products 2-4 weeks ahead of time to avoid potentially dangerous supplement/drug interactions, such as changes in heart rate, blood pressure and increased bleeding. Talk with your doctor about everything you are taking before the surgery – vitamins, minerals, and herbal supplements, as well as medications.

Some supplements are known to be dangerous

Just because a product is on the market does not mean it is definitely safe. There are some known toxic herbs that are still available to the consumer, such as: aristolochia (conclusively linked to kidney failure and cancer in the U.S., China, Europe, and Japan); yohimbe (a sexual stimulant linked to heart and respiratory problems); bitter orange (has effects similar to those of the banned stimulant ephedra); and chaparral (linked to liver damage).

Researching and buying vitamin, mineral and herbal supplements

The safest way to purchase supplements is from a reputable vitamin or health food store, or from a health practitioner. However, not all of us have access to these types of resources. As an Internet-savvy consumer, your computer can be your best friend when it comes to choosing the right supplement for you.

The amount of information available on the Web can be overwhelming, but by using the following simple steps, you can be sure you’re getting reliable information about herbal or vitamin supplements.

There are a lot of different companies marketing supplemental products. Quality does matter, so it’s good to read the ingredients and warnings on the bottle, and learn about the manufacturers. It's up to you as the consumer to protect your own health – so practice caveat emptor ("let the buyer beware."), and consult your health care professional before taking any type of supplements.

Related links for dietary supplements

What are dietary supplements?

What's in the Bottle? An Introduction to Dietary Supplements– General information on supplements. (National Center for Complementary and Alternative Medicine)

NIH Office of Dietary Supplements – Massive source of information from the National Institute of Health. Includes supplement fact sheets, consumer health alerts, and advice on safety when taking supplements.

Who can benefit from a vitamin or mineral supplement

The World’s Healthiest Foods – It’s possible to get most of your needed vitamins and nutrients from tasty, readily available foods. This website offers nutrition information on the healthiest foods you can eat. (George Mateljan Foundation)

Body-for-LIFE Vitamin Chart – Lists RDI (recommended daily intake) for key vitamins and minerals and provides useful summary about the supplement and potential toxicity via mouseovers. (BodyforLife.com)

Vitamins: Nutrition Source – Overview of key vitamins and why judicious supplementation is essential for good health. (Harvard School of Public Health)

Dietary Supplements - Age Page - Health Information – Special concerns relating to senior health and use of vitamin and mineral supplements. (National Institute on Aging)

Supplement safety

Herbal supplements: What to know before you buy — Primer on what to know before taking herbal supplements, including precautions and tips for purchasing. (Mayo Clinic)

USDA Warnings & Safety Information – Up-to-date alerts on safety concerns of various supplements and products. (USDA)

Herbal Health Products: What you should know – Describes some common side effects of popular supplements, and what to avoid if you suffer from certain conditions. (American Family Physician)

Choosing a vitamin, mineral or herbal supplement

Supplements Information – Allows you to look up a supplement by name, and find out background, dosing information, and pertinent research. For example, Coenzyme Q10 (Mayo Clinic)

Tips for the Savvy Supplement User – Overview containing tips for evaluating information (labels, books, internet resources) and guidelines for making informed decisions about whether or not to take supplements and how to purchase wisely. (U.S. Food and Drug Administration)

Suzanne Barston, Gina Kemp, M.A., and Jeanne Segal, Ph.D contributed to this article. Last modified on: 7/18/08.