Health Risks Associated With Dietary Supplements

If your daily diet includes a supplement of some sort, you might see it as a little dose of insurance that you're getting the nutrition you need. And you might be right, especially if you're using it because you have a certain ailment or deficiency. But a supplement that benefits one person may pose risks to another -- or it may interfere with prescribed medications. Even if the label says "natural," that's not a guarantee of safety.

About Dietary Supplements

You don't have to look beyond your local grocery store to find an array of dietary supplements --- tables, capsules, liquids and powders containing vitamins, minerals, herbs and other substances. Their health claims are everywhere, too, and a majority of American adults now take a supplement at least occasionally. Federal agencies oversee supplements' manufacturing safety and advertising claims, but they do not analyze their effectiveness before they are marketed to the public.

Benefits of Supplements

For most people, a healthy diet is the best nutritional insurance. Supplements can be beneficial, even vital to your health. For example, getting enough folic acid when you're pregnant reduces the risk of some birth defects, and fish oil may help if you have heart disease. Dietary supplements can fill in nutritional gaps if you're following a vegan diet, dealing with a gastrointestinal disease or coping with food allergies.

Risks and Hazards

Most vitamin and mineral supplements are considered safe as long as you do not exceed the recommended daily allowance. Megadoses can be hazardous. For example, too much vitamin D could cause nausea and weakness; too much vitamin C could cause diarrhea, vomiting and kidney stones. A supplement also may interfere with your prescription medications. For example, St. John's wort may reduce the effectiveness of drugs including antidepressants and birth control pills, while vitamin K can cut the effectiveness of a prescription blood thinner.

Precautions on Supplements

So, your friend assures you that a certain herbal supplement has been helping people in Europe or Asia for hundreds of years? That's OK, but before you buy a bottle, discuss it with your doctor. The FDA also urges skepticism about any supplement that promises a miracle cure. If you do take dietary supplements, check labels to make sure you don't exceed the daily recommended dose of any nutrient. And, bear in mind, that many foods are enriched with vitamins and minerals that add to your daily intake.