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Yes, You Can Take Too Many Vitamins

If you’re taking supplements, it’s important to understand which vitamins and minerals you can get too much of, like vitamin C and calcium

Person talking with doctor on a virtual call about vitamins

Worried you’re not getting enough of the vital vitamins and minerals your body needs to function at its best?

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You’re not alone. Many of us aren’t eating as many fruits and vegetables as we should be. In fact, Americans nationwide are significantly below the fruit and vegetable consumption guidelines set forth by the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture (USDA).

Instead, people may turn to supplements. And while vitamin and mineral supplements can be helpful, getting nutrients from pills rather than food isn’t always the best way to improve or help maintain your health. And in certain cases, it can even hurt. Plus, research shows food is the best route of vitamins and minerals in almost all cases.

So, can you overdo it on supplements? Can you take too many?

Yes. Too much of a good thing — in this case, certain vitamin and mineral supplements — can be toxic and cause a host of side effects.

Registered dietitian Beth Czerwony, RD, LD, shares which vitamins and minerals you may be overdoing it on — if you pop them as pills.

Which vitamins can you get too much of?

Certain vitamins and minerals can cause side effects if you consume too much. Czerwony outlines what to watch out for.

Beta-carotene and vitamin A

Beta-carotene and vitamin A — which is formed by beta-carotene — is easy to consume. If you have a bowl of cereal for breakfast, anything orange (carrots, sweet potatoes) for lunch and then a multivitamin or supplement for eye health, you’ve probably consumed over the recommended amount of beta-carotene and vitamin A.

If you consume too much vitamin A, you may experience side effects like:

  • Drowsiness.
  • Irritability.
  • Nausea and vomiting.

Too much vitamin A has also been associated with an increased risk of lung cancer and an overall increased risk of death.

Calcium

Sure, we know that calcium benefits bone strength, but the mineral can also improve muscle function and play a role in our blood pressure. Calcium supplements can help ensure that you reach the daily recommended amount of calcium, but it’s possible to take too many.

If you consume too much calcium (known as hypercalcemia), you may experience side effects like:

  • Nausea and vomiting.
  • Confusion.
  • Itching.
  • Irregular heartbeat.

Additionally, you could even damage your kidneys and increase the pH of your blood.

And while this can happen if you take too many supplements, even taking too much calcium carbonate (a main ingredient in Tums® or Rolaids®) can cause temporary hypercalcemia.

Folic acid

Folic acid is the synthetic form of vitamin B9. It can be taken as a supplement or added to fortified foods like breads, pasta, rice and flour. Vitamin B9 is essential for healthy cell growth and function. It also supports your immune system.

While it can be hard to get enough vitamin B9 without supplementation, it’s possible to take too much. And too much folic acid might disguise a vitamin B12 deficiency in older adults. Other side effects may include:

  • Bloating.
  • Loss of appetite.
  • Nausea and vomiting.

Iron and copper

Iron plays a key role in your diet when it comes to menstrual cycles and pregnancy, but the recommendations for iron after menopause significantly decrease. Despite the lower guidelines (8 milligrams per day after age 50), many postmenopausal individuals still take supplements that contain iron and copper. One study linked excess iron and copper to increased incidence of Alzheimer’s disease and heart disease.

If you consume too much iron or copper, you may experience side effects like:

  • Constipation.
  • Nausea and vomiting.
  • Stomach pain.
  • Diarrhea.

Czerwony says that severe iron overdoses could cause low blood pressure, liver failure, lung injury, coma and even result in death.

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Vitamin B3

Known as niacin, vitamin B3 is vital in maintaining the health of your heart, blood vessels and metabolism. Vitamin B3 is naturally found in animal products (think meat and fish), as well as plant-based foods like mushrooms, avocados and green peas.

Too much vitamin B3 can cause:

  • Red, itchy skin.
  • High blood pressure.
  • Stomach pain.
  • Impaired vision.
  • Liver damage.

Vitamin B6

You may know that vitamin B6 can help prevent anemia. But it can also improve your mood and protect your heart. You can find vitamin B6 in foods such as tuna, chicken liver, tofu and carrots. You may also be getting vitamin B6 through a B-vitamin supplement or multivitamin.

Vitamin B6 in high doses can cause irreversible nerve damage. Other side effects include:

  • Ataxia (loss of control of body movements).
  • Nausea and vomiting.
  • Heartburn.
  • Sensitivity to light.

Vitamin C

When most people think of vitamin C, they usually think of oranges. But if your first thought is a vitamin C pill, you may be overdoing it. One study found that males who took vitamin C pills had a higher risk of developing kidney stones.

Other side effects of too much vitamin C include:

  • Diarrhea.
  • Headaches.
  • Heartburn.
  • Nausea and vomiting.

Vitamin D

In America, vitamin D deficiency is prevalent due to a lack of UV (ultraviolet) ray exposure. As the best source of vitamin D is the sun, and excess exposure can increase your risk for melanoma, a supplemental route might be needed.

But too much vitamin D can lead to a buildup of calcium in your blood, again, known as hypercalcemia. This may lead to:

  • Frequent urination.
  • Nausea and vomiting.
  • Weakness.
  • Weight loss.

“Having too much vitamin D may also cause calcium to build up in the body, causing damage to the heart and potential arrhythmias,” warns Czerwony.

Vitamin E

It’s unlikely you can get too much vitamin E from the food you eat daily such as nuts and green vegetables.

But if you take a vitamin E supplement, your body will store any extra vitamin E in your liver and tissues. Too much vitamin E can affect how your blood clots, cause hemorrhages and even lead to a hemorrhagic stroke.

Zinc

You only need a small amount of this mineral — but it can have a big payoff on your health. Zinc prevents cell damage, protects your eyesight and helps lower your blood sugar and cholesterol.

If you take too much zinc, you may experience:

  • Nausea and vomiting.
  • Diarrhea.
  • Stomach cramps.

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What else can happen if you take too many vitamins?

We’ve established that taking too much of certain vitamins and minerals can be toxic and come with side effects. And much of this depends on whether you take water-soluble or fat-soluble vitamins.

If you take water-soluble vitamins such as vitamins C, B1 and B2, your body will remove any extra amount through your urine. But if you take fat-soluble vitamins, like vitamins A, D and E, your body absorbs and stores the full amount, which can lead to the problems outlined.

Again, while the side effects vary depending on what vitamin or mineral you’ve taken too much of, other common symptoms can include:

If you or someone else is experiencing symptoms of a vitamin overdose, call the Poison Help Hotline at 1.800.222.1222 to be connected to your local poison control center.

“You should seek medical attention if you have taken mega doses of vitamins — whether that's early on or if you have been taking them for several months and experience seizures, changes in mood, including irritability or confusion, increase in headaches or fatigue, or onset of GI [gastrointestinal] symptoms like diarrhea, vomiting or stomach cramps,” stresses Czerwony.

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