Dietary Supplements:

What are dietary supplements?

The Dietary Supplement Health and Education Act (DSHEA) defines a dietary supplement as a product other than tobacco 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.

According to the Harvard School of Public Health, "intake of several vitamins above the minimum daily requirement may prevent heart disease, cancer, osteoporosis, and other chromic diseases." 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.

Vitamin Supplements

Vitamin supplements provide extra supplies of micronutrients needed by the body for: growth, digestion and nerve function; metabolism of carbohydrates, fats, and proteins into energy; and cellular repair. Different vitamins come from different food sources, and a varied and healthy diet should provide you with many of them. A vitamin supplement can help you make up for those underrepresented in your diet.

Sample Vitamins and their Functions
Vitamin	Function	Source	RDA*
Vitamin A	Supports the immune system, bone growth, vision, cell division	Liver (including Cod Liver Oil) Dairy, Meats	2330 IU Adult Women 3000 IU Adult men
Vitamin B6	Supports protein and red blood cell (RBC)  metabolism	Grains, legumes, liver, bananas	1.6 mg women 2 mg men
Vitamin B12	Supports nerve cells and DNA synthesis	Clams, oysters, salmon, steak, cottage cheese and milk, fortified cereal	2.4 mg
Vitamin C	Antioxidant, supports connective tissue, nervous tissue, mitochondria	Citrus fruits, green veggies	60 mg
Vitamin D*	Supports normal levels of calcium and phosphorus	Cod liver oil Fish, fortified dairy products, eggs, sun exposure	200 IU
Vitamin E	Antioxidant, supports the immune system and repairs DNA	Vegetables oils, nuts, grains	12 IU women 15 IU men
Notes: *RDA is the Recommended Dietary Allowance. The RDA represents the known nutritional needs of 97.5% of the population. *Vitamin D should supplemented in the D3 form (rather than D2).

Mineral Supplements:

Mineral supplements provide micronutrients found extensively in bone and teeth. Minerals help the body:

• create new cells and enzymes
• distribute fluids  
• control nerve impulses
• bring oxygen and take away carbon dioxide from cells

Sample Minerals and Their Functions
Mineral	Function	Source	RDA or AI*
Calcium	Supports bone, teeth, blood, body fluid, muscle and blood vessel contraction, hormone and enzyme secretion	Dairy, green veggies, sesame seeds, almonds	1000 mg (age 19-50) 1200 mg (age 51+) 1300 mg (age 14-18)
Copper	Supports normal growth, bone growth, sugar metabolism, and proper enzyme function	Oysters, nuts, legumes, grains	2 mg (age 19+)
Iron	A metal that supports the transfer of oxygen and cell growth	Meats, fish, leafy green vegetables, molasses	8 mg (men, age 19-50) 18 mg (women, age 19-50
Magnesium	Supports muscles, nerve, heart, immune system, bones, blood pressure, energy metabolism, blood sugar levels, and protein synthesis	Nuts, seeds, grains, vegetables	400 mg (age 19-30) 420 mg (age 30+)
Selenium	Antioxidant, protects cells from oxidation	Nuts, whole grains, seafood	55 micrograms (age 19+)
Zinc	Supports enzyme production, wound healing, sense of taste and smell, DNA synthesis, and normal growth	Oysters, meat, seafood	11 mg (men, age 19+) 8 mg (women, age 19+)
Notes: *RDA is the Recommended Dietary Allowance. The RDA represents the known nutritional needs of 97.5% of the population. AI is the Adequate Intake recommended based on observed or experimentally determined levels. *Recommended amounts are different for Infants, children, and pregnant and lactating women.

Herbal Supplements

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.

Herbal supplements are different from vitamin and mineral supplements in that they are considered to have medicinal value. Herbs are:

• fresh or dried products that are extracts (or tinctures), tablets, capsules, powders, teas, roots or leaves
• a group of chemicals or a single chemical that has been isolated from a botanical
• used to maintain or improve health in a specific area of the body or organ systems

Select Herbal Remedies and Historical Uses
Herb	Historical Use
Black Cohosh	Malaise, gynecological conditions, kidney disorders, rheumatism, and,hives.
Echinacea	Upper respiratory infections.
Garlic	Lowers cholesterol, may slow hardening of the arteries
Ginger	Nausea, arthritis, osteoarthritis, joint, and muscle pain
Milk Thistle	Supports liver functions
Saw Palmetto	Supports bladder and kidney functions
Find fact sheets on other herbal and botanical supplements at the Office of Dietary Supplements.

Taking 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. As the Harvard report states, “A standard, store-brand, RDA-level multivitamin can supply you with enough of these vitamins for under $40 a year. It's about the least expensive insurance you can buy."

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)
• 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

Finding reputable information on specific supplements

Several online resources provide information on supplements. Two good ones to start with are Mayo Clinic Supplements Information; the supplement database on  Natural Standard; and the UC Berkeley Wellness Guide to Dietary Supplements.

Additionally, naturopathic doctors have extensive training in nutrient therapy and herbal medicine and can help you develop a supplement regime to correct nutrient deficiencies and optimize health. Naturopathic doctors are trained to use natural therapies and treatments whenever possible and to look for and treat the cause of a physical problem rather than just the symptoms. Reputable naturopathic doctors can be found through websites listed in the resources section below.

What to look for when buying vitamin, mineral and herbal supplements

There are a lot of different companies marketing supplemental products. Quality does matter so read the ingredients and learn about the manufacturers. It's up to the consumer to practice caveat emptor ("Let the buyer beware."). Always consult your health care professional before taking any type of supplements and purchase products from a reputable store or health practitioner.

When you shop for health supplements, look for the following:

• Established brands. Certain companies have been manufacturing quality supplements for decades. Research or ask questions to determine the best brands.
• Specific herbal information. You should know the Latin name of an herb, including genus and species, or the common name of the herb you want. Most herbs have more than one species, and not every species has medicinal value. 
• Mystery ingredients or “flowering agents.” Many supplement manufacturers use “fillers” to make the production of the supplement easier and faster. Examples of fillers, often referred to on the label as “flowering agents,” are magnesium stearate, palmitic acid, stearic acid, gelatin, silica and other artificial colors or flavors. They compromise the effectiveness of the nutrients in the supplement, and some people may experience side effects from them. 
• Customer service information. Ideally, either a toll-free phone number to call, a website, or both.
• Recommendations for use. Does the bottle or other container clearly state how much of the supplement to take and when?
• Amount per serving and % Daily Value (the latter will say "Daily Value not established" for herbs).
• Additives statement. The product should state whether it is free of common allergens, such as corn, wheat, and milk.
• Warning statement. For example, "Do not use if you are pregnant."
• Lot number. Helps manufacturers locate the original batch if problems arise.
• Expiration date. Make sure it's post-dated for at least the length of time you will spend using up the contents.
• Storage instructions.

Supplement labeling

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 refers 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

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. In addition:

• Don't substitute supplements for medication. If you plan to use a dietary supplement in place of drugs, consult your health care provider first. Many supplements contain active ingredients that have strong biological effects and their safety is not assured.
• Be cautious about drug interactions. Some supplements may interact with prescription and over-the-counter medicines. Taking a combination of supplements or using the products with medications (whether prescription or OTC drugs) can cause dangerous interactions which could be life-threatening. 
• 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.
• 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, 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).

For herbal supplements, also follow the guidelines below:

1. Choose standardized herbal extracts. Standardization ensures product consistency from one batch to the next.
2. Look for the ingredient COA (Certificate of Analysis), which guarantees the potency and safety of that ingredient.
3. Choose herbs that are highly bioavailable. The active ingredients in many supplements are destroyed by stomach acid. The best herbal product is one that is designed to bypass or survive the digestive process.
4. Choose single herb supplements rather than compounds or blends. This way you'll be better able to gauge how well the supplement is working for you.

Concerns for seniors

People over 50 may experience changes in digestion and nutrient absorption that could make supplementation prudent. Consider talking with your health professional about whether you need to pay special attention to supplementing the following vitamins and minerals to reach the amounts listed:

• Vitamin B12 – 2.4 mcg (micrograms) per day. Some foods, such as cereals, are B12 fortified, but up to one-third of older people can no longer absorb natural vitamin B12 from their food. B12 keeps blood and nerves healthy. See Vitamin B12.
• Vitamin B6 – 1.7 mg for men and 1.5 mg for women. B6 is needed for forming red blood cells.
• Calcium – 1200 mg (milligrams), but not more than 2500 mg a day. As you age, you need more calcium and vitamin D to keep bones strong. Bone loss can lead to fractures, mainly of the hip, spine, or wrist, in both older women and men. See Calcium.
• Vitamin D – 400 IU (international units) for people age 51 to 70 and 600 IU for those over 70, but not more than 2000 IU each day.
• Iron – 8mg per day for men and postmenopausal women. Higher amounts for women past menopause who are using hormone replacement therapy. Iron helps keep red blood cells healthy. See Iron.

Of course, the time-honored wisdom for healthy aging still applies: eat a nutritious diet, exercise regularly, keep your mind active, don't smoke, and see your doctor for check-ups.

References and resources for dietary supplements

Helpguide Series: Healthy Eating

Part I of this series is filled with practical tips and suggestions to help you enjoy your meals and be healthy.  Part II is filled with guides to manage your weight and help control, prevent, and heal from heart disease /stroke, cancer, diabetes and osteoporosis.

Part I - Enjoy your Meals with Healthy Food:  

Healthy Eating – Discover the benefits of a healthy diet, understand the new food pyramids and get tips on calorie and water intake.

Healthy Fast Food – Learn how to make healthy choices while enjoying the pleasure of dining out.

Healthy Weight Loss – Guide to eight popular diet plans and tips for managing your weight.

Healthy Recipes – Fabulous recipes from around the globe – fast, weight-conscious and tasty! 

Dietary Supplements – Get tips on selecting the supplement(s) best-suited for you.

Healthy Eating for Kids and Teens – Learn how to help your children develop and maintain healthy eating habits.

Nutrition for Women – Nutritional tips for women of all ages and information on pregnancy, bone health, and hormones.

Senior Nutrition / Creative Meal Sharing – For people who have lost their enjoyment in eating and those who care for them.

Organic Foods – Learn how organic food can help you minimize the effects of pesticides, GMOs, and food irradiation.

Healthy Fats – Find out about the value of good fats to your diet and how to choose healthy fats.

Part II - Diets for Special Health Problems:  

Diabetes – Learn which diets are best for preventing and treating diabetes.

Cancer – Learn how a healthy diet can reduce your risk of cancer and what specific foods help prevent cancer.

Heart Disease and Stroke – Learn about LDL levels, essential fatty acids, fiber and the DASH diet.

Osteoporosis – Determine if you are getting enough Calcium and Vitamin D to prevent and heal osteoporosis.

Other Related Links

Dietary and Herbal Supplements – Articles plus info on many supplements. (National Center for Complementary and Alternative Medicine)

• Dietary Supplements: Background Information
• What's in the Bottle? An Introduction to Dietary Supplements 

Guides to specific supplements

Supplements Information – Considerable information on supplements and their usefulness for specific conditions. Information from Natural Standard® Patient monograph.(Mayo Clinic)

• For example Coenzyme Q10

Wellness Guide to Dietary Supplements – Provides numerous in-depth reports on a wide range of dietary supplements, from Alpha-lipoic acid to Wheat grass. Much of this information is available free of charge (without a subscription). (UC Berkeley Wellness Letter)

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)

FDA/CFSAN Overview of Dietary Supplements – Extensive Q&A concerning the FDA's role in regulating dietary supplements and the consumer's responsibility. (FDA/Center for Food Safety and Applied Nutrition)

Dietary Supplement Fact Sheet – Quick guide to who should think about taking dietary supplements and regulations governing supplements. (Missouri Families)

FDA MedWatch – Resource for health care professionals to reporting adverse effects or product quality issues with specific dietary supplements. Medical Product Safety Information section provides information about problems that have already been reported. (U.S. Food and Drug Administration)

Standards and Government Regulations – Discusses the extensive industry standards and federal and state regulations regarding product quality, labeling and safety. Includes links to numerous other articles on these topics. (SupplementQuality.com)

Study Suggests Coenzyme Q10 Slows Functional Decline in Parkinson's Disease – Example of Scientific Study (NINDS - National Institutes of Health)

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)

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)

Additional Resources for Dietary Supplements

Nutrition 21 Testimony (PDF) – Plans to implement the DSHEA to meet 21st century needs, focusing on improving health outcomes using dietary supplements, education & communication, and advocating for the inclusion of dietary supplements into mainstream medicine. (NIH Office of Dietary Supplements)

Council for Responsible Nutrition Position Statement (PDF) – Proposal for a tax policy to encourage consumers to use dietary supplements wisely by making supplements a deductible medical expense under Flexible Spending Accounts. (CRNUSA.org)

Executive Summary – Provides a summary of The Dietary Supplement Health and Education Act (DSHEA) of 1994, including findings, guidance and recommendations. (U.S. Department of Health and Human Services)

Medline Plus Medical Encyclopedia: Vitamin Safety – Brief definition of vitamin safety. (NLM/NIH)

Government vitamin safety data slanted says ION – This report is based on UK research on Vitamin B6 safety studies versus government warnings. (Newmediaexplorer.org). Cross reference with this Commentary on Government vitamin safety data slanted says ION by the Orthomolecular Medicine News Service. (Newmediaexplorer.org)

Other resources that we used when writing this article

Dietary Supplements: Background Information – Describes what constitutes a dietary supplement and what regulations and standards govern supplements in the U.S. Also includes information about labeling. (Office of Dietary Supplements)

Food and Nutrition: Choice for Health/What Are Dietary Supplements? – How the 1994 Dietary Supplement Health and Education Act expanded the definition of dietary supplements along with consumer responsibility for making smart choices. (Iowa State University Extension)Vitamins: Nutrition Source – Overview of key vitamins and why judicious supplementation is essential for good health. (Harvard School of Public Health)

Intelihealth: Vitamin Supplements – Summary of specific groups who may be at risk and can benefit from supplementation. (Reviewed by faculty members of Harvard Medical School)

What to look for when buying supplements – Short consumer guide to making wise supplement purchases. (Epnet.com – EBSCO Publishing)

Herbal FAQ — Extensive Q & A on every aspect of herbal supplementation, from safety to effectiveness to when to use herbal supplements. Prepared by "The Voice of the Herbal Products Industry." (National Wellness Association)

Dangerous Supplements: Still at Large – Details specifics about several dangerous supplements still available nationwide and provides consumers with information about the important differences between regulations for drugs and regulations for supplements. (Consumer Reports)

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

Gina Kemp, M.A., and Jeanne Segal, Ph.D contributed to this article. Last modified on: 4/20/07.