4 Reasons Supplements Aren’t Always All They’re Cracked Up to Be

image of vitamins, omega 3, cod-liver oil, dietary supplement and tablets an embankment on a light background close up, the top view

We live in a society where ordering fast food from a drive-in window and heating up packaged foods in a microwave is the norm. Most people are so pressed for time that they grab what’s convenient, even if it is overly processed and devoid of nutrients. There’s a reason there’s usually a line at the McDonald’s drive-thru window!

To make up for dietary shortfalls, a growing number of people are taking dietary supplements in hopes of getting in pill form what their diet lacks – and they have a lot to choose from. Projections are that the supplement market will be a 220.3-billion-dollar market by the year 2022, thanks to the growing demand for nutrients in supplement form.  Supplements come in a variety of forms – pills, liquids, powders – and may include isolated vitamins or minerals, combinations of the two and sometimes herbs and other components you find in food, like antioxidants, in isolated form.

The allure of taking supplements appeals to people of all ages. Pop a pill as an insurance policy against deficiencies or take one in hopes of getting other benefits, like weight loss or slower aging. It’s a way to “cover the bases” if you eat a less than stellar diet and lower the risk of nutrient shortfalls. People also take them with the belief that they can help with weight loss, improve sports performance, slow aging, or lower the risk of developing one or more diseases. Of course, supplement manufacturers play to people’s hopes, fears, and desires by using language that suggests benefits and by using images of youthful, energetic people in their ads. However, supplements don’t always live up to their hype and, in some cases, may not even be safe. Let’s look at some of the reasons supplements aren’t all the manufacturers claim.

Taking Supplements Can Create Nutrient Imbalances

Your body is a finely tuned machine that thrives on a particular ratio of nutrients. If you take a high dose of one vitamin or mineral, it can potentially create an imbalance with another. One example is minerals. You need a variety of minerals for health, including iron, calcium, zinc, copper, and magnesium. These minerals are similar in structure and compete with each other for absorption, as they use the same transporters to get into the bloodstream. If you take high doses of one, it can potentially interfere with the absorption of another. This plays out in clinical practice. For example, high doses of zinc can cause a copper deficiency by blocking the absorption of copper. Fortunately, most zinc supplements contain added copper to prevent this – but you can still see how taking high doses of one micronutrient can throw something else out of balance. You’re unlikely to encounter this situation with food.

Isolated Components from Supplements May Behave Differently than Food

When you isolate a micronutrient or other component from food, it doesn’t necessarily have the same benefits as it would if you got it through diet. Food contains contain a variety of micronutrients and plants are a rich source of thousands of phytonutrients with potentially health-promoting properties. These compounds work together, not in isolation. In fact, taking an isolated food component as a supplement may actually be harmful. For example, a study that followed 29,000 smokers for 6 years found that those who took supplemental beta-carotene, a derivative of vitamin A, had a higher risk of lung cancer relative to those who didn’t. In fact, heart disease, lung cancer, and overall mortality were greater in those who took beta-carotene. We tend to think of supplements as being protective, but excess amounts of some may be harmful.

Supplements May Contain Unwanted Components

Supplements aren’t subject to the same regulations as drugs. For a drug to enter the market, it must undergo extensive testing and be reviewed by the FDA before it can be approved. Even then, drugs reach the market that later turn out to have unforeseen risks and side effects. The same isn’t true of supplements. The FDA only requires that supplement manufacturers use good manufacturing practices and quality control when producing them. A supplement is only scrutinized and pulled from the market when the FDA gets reports of adverse reactions.

How do you know what you’re getting? Fortunately, there are independent firms that test supplements for impurities and publish the results. This testing frequently reveals impurities, sometimes dangerous ones. For example, testing of some supplements uncovered heavy metals and even prescription medications in some supplements.

Weight loss and bodybuilding supplements are particularly prone toward adulteration.  For example, testing of a Chinese weight loss supplement showed it contained sibutramine and phenolphthalein, two banned medications.

You May Not Get What You Bought the Supplement For

Just as supplements can have impurities, like drugs and heavy metals, they can also be almost devoid of what you purchased them for. An investigation of herbal supplements a few years ago revealed that some so-called herbal supplements from reputable stores, like GNC, contained NONE of the active ingredients and were made up almost exclusively of filler.

When Supplements ARE Beneficial

There are times that supplements are beneficial or even necessary. For example, during pregnancy, you need supplemental folate to prevent neural tube defects in an unborn baby. If you eat a vegan diet, you need supplemental vitamin B12, as you don’t find vitamin B12 in plant foods. If you have certain health problems where you don’t absorb some nutrients as easily, for example, inflammatory bowel disease, you may need supplements to avoid a deficiency. Plus, some medications can deplete particular vitamins and minerals.  If you don’t fall into one of these special categories, it’s usually best to get micronutrients from food rather than supplements as you get the added synergy.

The Bottom Line

Get your diet in order before considering supplements. Use supplements when you can’t get enough of a certain component through diet alone or if you have a health problem that can benefit from supplementation. If you do take supplements, research the companies you buy them from carefully or consider getting a report from one of the independent testing firms before placing an order.




JAMA Intern Med. 2013;173(10):929-930. doi:10.1001/jamainternmed.2013.379.
Science-Based Medicine. “What’s in Your Supplement?”
Zion Research. “Global Dietary Supplements Market will reach USD 220.3 Billion in 2022: Zion Market Research”
WebMD. “Death Stalks Smokers in Beta-Carotene Study”


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6 Health-Saving Facts You Should Know Before Taking Supplements

Are Probiotic Supplements Overhyped?

Do the Supplements You’re Taking Really Contain What You Think They Do?

3 Types of Supplements You Should Think Twice Before Taking

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