Pros & Cons of Dietary Supplements

Over half of the adults in the U.S. use at least one type of dietary supplement, the most common being multivitamins, according to the Centers for Disease Control and Prevention. The term "supplements" encompasses a variety of products such as vitamins and minerals, herbs and enzymes. Taking the right supplements can be beneficial to your health, but they are not without risk. Never take any type of supplement without first talking to your doctor.

As the name implies, supplements add to your diet. If your diet is lacking in a certain nutrient -- like vitamin B-12 because you're a vegan -- you can get the extra nutrition you need in supplement form. With that said, don't rely on supplements to take the place of a healthy, balanced diet. It is best to get the nutrition you need from food sources.

Supplements also offer separate health benefits and can help combat chronic diseases. For example, regularly taking fish oil supplements may help lower blood pressure and triglycerides and decrease your risk of heart disease. Chamomile can help soothe sore throat and upset stomach and improve sleep; and St. John's Wort may help improve mild depression.

You have to be extra careful when taking supplements if you're taking medication. Many herbs and vitamins interfere with medications, either causing potentially dangerous side effects or rendering the medication ineffective. Vitamin K can reduce the effectiveness of blood thinners; St. John's Wort can reduce the effectiveness of antidepressants and birth control pills; and antioxidants, like vitamin C and E, can reduce the effectiveness of some types of chemotherapy. If you're on medication, never take any type of supplement without the consent of your doctor.

Dr. Kelli Ward, an osteopathic physician from Arizona, notes on the American Osteopathic Association website that many multivitamins contain synthetic nutrients instead of natural nutrients. Your body cannot absorb synthetic nutrients as well as natural ones so you may not be getting as much nutrition as you think you are. Ward recommends choosing all-natural vitamin and mineral supplements made from food sources. That way, your body will be able to absorb more of the nutrients from the supplements.

When used as prescribed or suggested on the bottle, supplements are generally safe; in most cases, problems with toxicity occur as a result of inappropriate or excessive usage. For example, excess intake of vitamin A can contribute to birth defects, reduce bone mineral density and damage the liver. Too much iron can cause diarrhea, nausea, dehydration, low blood pressure, dizziness, fever, chills, headache and flushing. Overdoing it on vitamin D can lead to hypercalcemia -- or too much calcium in the blood.