Americans have been taking multivitamins and mineral supplements since the early 1940s, when the first of these products became available.

Americans have been taking multivitamins and mineral supplements since the early 1940s, when the first of these products became available. Since then, use of dietary supplements has skyrocketed. According to a 2018 Council for Responsible Nutrition Consumer survey, about 75 percent of adults take some kind of dietary supplement, and among these adults, almost 30 percent take four or more supplements daily. There are more than 50,000 dietary products on the market today.

A dietary supplement (as defined by the United States Congress in 1994 as part of the Dietary Supplement Health Education Act) is a product (other than tobacco) that:

Is intended to supplement the diet,

Contains one or more dietary ingredients, including vitamins, minerals, herbs or other botanicals, amino acids or other substances; or their constituents,

Is intended to be taken by mouth as a pill, capsule, tablet, or liquid, and

Is labeled on the front panel as being a dietary supplement.

According to the Food and Drug Administration (FDA), dietary supplements are not drugs. Hence they are subject to much less strict regulation than drugs or medicines that are intended to treat disease.

If you don’t eat a variety of nutritious foods or if you are deficient in a particular nutrient, supplements can fill the gap. But just because dietary supplements are available over the counter does not mean you can assume they are safe to use as you please. Supplements are not risk free. Following are seven top hazards of dietary supplements.

1. You might have an adverse reaction. The FDA fielded more than 6,300 reports of serious adverse events associated with dietary supplements from 2007 to 2012. This included 115 deaths, more than 2,100 hospitalizations and more than 900 emergency room visits. The laws make it difficult for the FDA to control dietary supplements. Most are banned or taken off the market only after being proven to cause harm.

2. Some dietary supplements are spiked with prescription drugs. Since 2008, the FDA has recalled more than 400 supplements that were found to contain ingredients similar to or the same as those found in a prescription drug. Most of these supplements were marketed for body building, sexual enhancement and weight loss.

3. You can overdose on supplements — even simple vitamins or minerals. Unless your health care provider tells you that you need more than 100 percent of the recommended daily allowance for a particular nutrient, you likely don’t. Mega doses of fat-soluble vitamins, including A,D, E and K, can accumulate in the body and cause gastrointestinal problems, inflammation, birth defects and liver failure. Excess minerals can cause metal toxicity. So many foods and beverages are now fortified with various vitamins and minerals that it is easy to get too much.

4. You can’t depend on warning labels on dietary supplements. Except for iron, the FDA doesn’t require any warning labels about the risk of accidental overdose or potential fatal poisoning in children.

5. Dietary supplements cannot cure a major disease. If the supplement claims to diagnose, cure, prevent or treat a disease, avoid it. These claims are not allowed, but with so many supplements on the market, they are difficult to stop.

6. Protection from heart disease or cancer is not proven. Taking antioxidants won’t prevent cancer, nor will taking fish oil prevent heart disease.

7. You might experience an interaction between various supplements or between supplements and prescription medications. Some supplements, such as St. John’s wort, speed up the breakdown of many drugs, making them less effective. Antioxidants like vitamin C or E can decrease the effectiveness of some chemotherapy drugs. Other supplements can increase the effect of a prescription drug. 

The most likely causes for harm from dietary supplements are using them in place of prescription medications or using multiple supplements. It’s much safer and better to get nutrients from whole foods. Isolated nutrients, as in supplements, are harder to metabolize and react differently in the body than nutrients delivered together in whole food.

You likely do not need to take any dietary supplements, but if you are interested, discuss it first with your health care provider. Also, ask your pharmacist about any possible side effects and potential interactions with other supplements and prescriptions you take.

Steer clear of any supplements that make drug-like claims or unrealistic promises. Read labels to avoid doubling up on vitamins or minerals, which could result in an overdose. Remember that many foods and beverages have vitamins and minerals added as well. 

Make sure to include all supplements, including dosage and how often you take them, in medication lists shared with doctors and pharmacists.