It’d be great if we all ate a healthy, well-rounded diet that included all of the vitamins and minerals we needed. In reality, that doesn’t always happen.

Many people choose to add supplements to their diet such as a multi-vitamin and/or a supplement with a concentrated dose of just one vitamin or mineral. For people who don’t like to swallow pills, there are even gummy vitamins that taste like candy. All of these things are generally thought of as healthy and good for you.

Many supplements state that they help build strong bones or support your immune system. Others promote weight loss or heart health. While these claims may be true, have you ever stopped and wondered if there’s such a thing as too many supplements? Like, can you overdose?

Many supplements contain way more than 100% of the recommended daily value of your vitamin intake. Do we really need 800% of our daily value of vitamin C, for example? Is that a good thing or a bad thing?

We were curious, so we decided to find out.

According to Dr. Seres, “Taking a higher dose of something that the body needs—despite misleading claims such as ‘supports heart health’—does not ensure that it will be beneficial, or even safe.”

Overdosing on vitamins and minerals can cause serious side effects. For example, too much iron can damage your internal organs, and too much calcium can lead to fatigue, confusion and vomiting. Have headaches or diarrhea? It could be due to too much zinc.

There are also certain ingredients in some supplements that can be life-threatening. We’re talking organ damage, cardiac arrest and cancer. An article in Consumer Reports strongly recommends staying away from the following ingredients which are commonly found in supplements in the United States: aconite, caffeine powder, chaparral, coltsfoot, comfrey, germander, greater celadine, green tea extract powder, kava, lobelia, methylsynephrine, pennyroyal oil, red yeast rice, and yohimbe.

If you take supplements and prescription drugs, make sure you let your doctor or pharmacist know what you’re taking. Some supplements can have negative interactions with some prescriptions. For example, herbal remedies like green tea extract and ginger shouldn’t be taken with blood thinners or aspirin.

Beth Kitchin, PhD, assistant professor of nutrition studies at the University of Alabama at Birmingham, prescribes vitamins C and D to patients with osteoporosis, but she’s careful to look at their diet first to make sure they’re not getting too much of these vitamins. She says, “For the average healthy person, you probably don’t need a multivitamin, multimineral supplement.”

Kitchin’s recommendation is that if you’re going to take supplements, or a multivitamin, make sure the daily value of the nutrients doesn’t exceed 100%. She personally takes a half-dose (one pill instead of two) of a multivitamin every day.

Kitchin emphasises that, “You really can’t get toxic doses of nutrients through food, but you can absolutely get toxic doses through supplements.”

David Jenkins, MD, professor of medicine and nutritional sciences at the University of Toronto, says, “Pills are not a substitute for a good diet—plant-based, fruit, veggies, whole grains, nuts, and seeds. They are packed with what you need.”

So, while a multi-vitamin that doesn’t contain more than 100% of your daily value of any nutrient probably won’t hurt you, be sure to tell your doctor what you’re taking, and if you eat a healthy diet, you probably don’t need any supplements at all.

Do you take any supplements?