Over 150 million Americans take dietary supplements, according to the Council for Responsible Nutrition, including vitamins, minerals, herbs, weight loss and sport-related supplements. Although not designed to replace healthy foods, appropriate use of dietary supplements may add benefits to your overall diet and wellness. Not all supplements are created equal however, many pose potentially serious risks. For best results, seek guidance from your doctor.
Side Effects
Although many dietary supplements may seem safe, particularly when they carry labels reading "all natural" or derive from natural foods and plants. Like medications, however, they pose a variety of potential side effects. St. John's wort, which is said to relieve depression symptoms, may cause sun sensitivity, allergic reactions, fatigue and upset stomach, according to the University of Maryland Medical Center. Valerian, used to treat anxiety and sleep problems, causes overstimulation in some people. Calcium supplements may lead to constipation.
Drug Interactions
A study published in the 2008 "Journal of the American Medical Association" researched analyzed prescription, over-the-counter and dietary supplement use in 3,005 adults ages 57 to 85. Forty-nine percent of the participants consumed dietary supplements regularly, often in addition to medications. Dietary supplements may interact with other supplements and with drugs, both over-the-counter and prescription. Calcium supplements may make it difficult for your body to absorb iron and zinc. Vitamin D supplements can interfere with corticosteroid medications, such as prednisone and weight-loss drugs.
Cardiovascular Risks
A variety of supplements aimed at appetite control, increased energy, weight loss and sports performance contains stimulants, such as caffeine, ginseng, green tea, extract or bitter orange. Stimulants increase your heart rate, particularly when consumed in high doses, and increase your risk for high blood pressure, heart palpitations and cardiovascular events, such as heart attack and stroke. Bitter orange contains substances similar to ephedra, which was banned by the Food and Drug Administration for serious reactions, some of which were deadly, according to MayoClinic.com dietitian Katherine Zeratsky. Although modest caffeine intake is generally considered safe, high-dose supplements or pairing stimulatory supplements with energy drinks, coffee or other stimulants, can surpass safe, moderate levels.
Toxicity
Toxicity refers to the degree a substance causes harm. Dietary supplements may cause acute or chronic toxicity. Consuming supplements that contain "mega-doses" of particular ingredients or not following proper dosage instructions increases your risk for toxic effects. In a study published in the "Journal of Medical Toxicology" in June 2008, researchers examined the reports of dietary supplement-related poison control center calls during 2006. Of the 275 phone calls, 41 percent involved symptoms directly linked with supplement use; two-thirds were likely linked to dietary supplement, as well. Eight of the callers required hospitalization. Caffeine-containing supplements showed the greatest potential for toxicity. In only five cases, toxicity was deemed "unlikely." Toxicity symptoms vary but may include headaches, fatigue, dizziness, nausea, vomiting, abdominal pain and difficulty thinking clearly.
References
- Council for Responsible Nutrition: Industry Regulation: Dietary Supplements
- University of Maryland Medical Center: Herbal Medicine
- Office of Dietary Supplements: Calcium Fact Sheet
- Office of Dietary Supplements: Vitamin D Fact Sheet
- "Journal of the American Medical Association"; Use of Prescription and Over-the-counter Medications and Dietary Supplements Among Older Adults in the United States; Dima M. Qato et al.; 2008
- "Journal of Medical Toxicology"; Dietary Supplement Adverse Events: Report of a One-Year Poison Center Surveillance Project; Christine A. Haller et al.; June 2008
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