Understanding the Functionality of Dietary Supplements

It's highly likely that your kitchen cabinet houses a few dietary supplements. Studies indicate that almost 70% of Americans consume these products, contributing to a $19 billion industry in 2015. More astonishingly, the global market for dietary supplements is projected to reach an impressive $278 billion by 2024, driven by the growing reliance on supplements to address malnutrition and cardiovascular disorders [sources: Council for Responsible Nutrition, Globe Newswire].

Dietary supplements come in various forms such as tablets, capsules, powders, or liquids, and are packed with vitamins, minerals, herbs, amino acids, and/or enzymes. Individuals turn to these supplements not just for maintaining health, but also to sidestep prescription medications, manage weight, or boost athletic and sexual prowess. This practice is far from new.

The use of dietary supplements dates back to the earliest civilizations. Ancient Sumerian clay tablets, over 5,000 years old, bear inscriptions of herbal remedies, marking the first known written records. Furthermore, Asian societies have a long-standing tradition of herbal medicine, tracing back more than 3,000 years. The first English-language book on herbs was released in 1526 [source: Herbal Academy].

The supplement industry is thriving and expanding, driven by endorsements from doctors, personal testimonials from friends, and vigorous marketing campaigns by supplement manufacturers. In the U.S., the majority of supplement consumers opt for vitamins and minerals, with multivitamins being the top choice, followed by vitamin D, vitamin C, and calcium. In the specialty supplement sector, Omega 3/fatty acids, fiber, and probiotics lead the pack, while herbal and botanical favorites include green tea, cranberry, garlic, and ginseng. Both men and women show equal enthusiasm for these products [source: Council for Responsible Nutrition].

As with other health-related products or practices, supplement advice is continually evolving with scientific advancements. In 2013, women were left confused when the U.S. Preventive Services Task Force advised against postmenopausal women taking calcium and vitamin D, citing no benefit in preventing bone fractures. Worse, some studies associated calcium supplements with heart disease, kidney stones, and gastrointestinal issues.

On the other hand, a study by the Women's Health Initiative revealed that long-term use of calcium and vitamin D did significantly reduce the risk of hip fractures in postmenopausal women, with minimal risk of kidney stones. This conflicting information leaves many wondering who to believe. Currently, many physicians recommend that patients of all ages avoid calcium supplements and instead consume three to four servings of calcium-rich foods daily [sources: Cooper, Ray].

Equally troubling as the ever-changing supplement guidelines is the reality that many individuals are consuming a vast array of supplements lacking scientific validation for their effectiveness.

Federal Regulation of Supplements

One of the most significant risks associated with supplements is the industry's minimal regulation, a critical fact consumers must understand. This wasn't always the case. Before 1990, the Food and Drug Administration (FDA) tightly regulated dietary supplements, nearly causing the industry to collapse. At that time, "dietary supplements" referred only to essential nutrients like vitamins, minerals, and proteins, with herbs added after 1990. However, a major shift occurred in 1994 [source: FindLaw].

In 1994, Congress enacted the Dietary Supplement Health and Education Act (DSHEA), broadening the definition of "dietary supplement" to include amino acids (e.g., lysine, tryptophan), metabolites, and extracts (e.g., bilberry extract, chamomile tea), among other substances. The act also classified supplements as food rather than drugs or food additives. This change significantly reduced federal oversight, leading to a surge in the industry [sources: FindLaw, Scarbrough, Institute of Food Technologists].

In return for reduced regulation, dietary supplement manufacturers were prohibited from claiming their products could cure diseases (which would classify them as FDA-regulated drugs). They were also required to list all ingredients on product labels and identify the product as a "dietary supplement." While labels could state the supplement's benefits, they had to include the disclaimer: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease." Manufacturers were responsible for ensuring product safety, though the secretary of Health and Human Services could declare a supplement or its ingredients hazardous [source: FindLaw].

The FDA has implemented good manufacturing practices for supplement producers to ensure products meet advertised standards, such as correct ingredient levels and absence of contamination. The FDA occasionally inspects manufacturing facilities, but unlike drugs, supplements do not require FDA approval before being marketed [source: National Institutes of Health].

To enhance supplement safety, several independent organizations conduct quality testing. If a supplement passes these tests, it earns a seal of approval, ensuring proper manufacturing, accurate ingredient labeling, and safe contaminant levels. Prominent testing bodies include ConsumerLab.com, NSF International, and U.S. Pharmacopeia. Notable supplements with quality seals include those from Kirkland (Costco), NatureMade, and Nutrilite (Amway) [sources: National Institutes of Health, Quality Supplements, NSF].

However, a quality seal doesn't guarantee a supplement's effectiveness or safety for every individual, which remains a topic of ongoing debate.

Wise Supplement Usage

The most common questions about supplements revolve around which ones to take and which to avoid. The answer depends on your body's unique needs, so always consult your physician before starting any supplement. Consumer Reports and the Natural Medicines Comprehensive Database, an independent research group, have identified supplements likely to be safe and may be effective for specific conditions. These include:

The two groups also highlighted a dozen supplement ingredients to avoid due to their association with severe side effects:

For instance, coltsfoot, believed to help with bronchitis and asthma, is associated with liver damage and cancer. Bitter orange, often promoted for weight loss, nasal congestion, and allergies, may lead to fainting, heart attacks, strokes, and even death [source: Consumer Reports].

While having "good" and "bad" lists can be helpful, avoid purchasing all 11 of the "good" supplements listed above without consideration. Your body may not require them, and the evidence supporting their effectiveness is often conflicting. For example, some studies suggest glucosamine sulfate alleviates pain and improves joint function in arthritis patients, while others indicate it only reduces joint pain [source: Arthritis Foundation].

Lastly, supplement quality varies widely. To make informed choices, follow these guidelines [source: U.S. Food & Drug Administration]:

Be cautious of supplements promising rapid weight loss, muscle building, or enhanced sexual performance. Many contain harmful ingredients, steroids, or prescription drugs. For example, ephedra, a Chinese herb marketed for weight loss, contained ephedrine, which stimulated the nervous system and constricted blood vessels. Linked to over 15 deaths by 1996, it wasn't banned by the FDA until 2004 after a major league baseball player's death [sources: Couzin-Frankel].

Food vs. Dietary Supplements

Food enthusiasts can celebrate: Experts recommend getting vitamins and minerals from fresh, flavorful foods rather than supplements. However, many people, especially Americans, consume processed foods, refined grains, and added sugars, which lack nutritional value. This issue worsens with age, as older bodies struggle to absorb nutrients efficiently, and seniors often eat less due to reduced appetites. As a result, many individuals fail to obtain necessary nutrients from their diets alone.

If your diet lacks sufficient nutritious food, dietary supplements can help bridge the gap. However, experts advise prioritizing healthier eating habits before turning to supplements. This is because the way nutrients are consumed is just as important as the nutrients themselves.

Food is rich in essential nutrients and phytochemicals, which are plant-based compounds with disease-fighting properties. For instance, allicin in garlic combats bacteria, and isoflavones in soy may alleviate menopausal symptoms for some women. These phytochemicals can also improve bioavailability, enhancing the absorption of vitamins and minerals. However, supplements do not contain these beneficial compounds [sources: Berkeley Wellness, Phytochemicals].

Additionally, the nutrients in food work synergistically. Drinking a glass of milk provides not only vitamin D and various nutrients but also lactose, which aids in the absorption of calcium and magnesium. In contrast, a supplement only offers vitamin D. Overconsumption of vitamin D or other supplements can also disrupt the body's ability to absorb nutrients effectively.

Although the nutrients in supplements and food may be chemically identical, their effects on the body can differ. A study by the University of Pennsylvania School of Medicine found that Omega-3s from fatty fish were more effective in maintaining healthy blood pressure in mice compared to those from fish oil supplements. The study highlighted how docosahexaenoic acid (DHA) in fish dilated blood vessels, while the DHA ethyl ester in supplements did not and even interfered with natural DHA [source: Science Daily].

Therefore, focus on consuming more fresh foods. Only take supplements advised by your doctor and avoid unnecessary ones. Stay informed with the latest updates on this topic to make well-rounded decisions.