Are You Taking Too Many Vitamins? Here's What to Know (2024)

If you are one of the many adults in the United States who takes one or more supplements daily, you may wonder if it's possible to take too many vitamins. How many vitamins you can take in a day depends on the supplement and how much of the vitamin you already get in your diet. Combining too many supplements or taking more than the recommended dosage can increase the risk of overdose.

Keep in mind that the Food and Drug Administration does not have to test supplements for efficacy or safety before they hit the market. Always consult a healthcare provider before taking a new supplement. They can tell you how much of each nutrient you need. Learn more about how to take supplements safely.

Supplements come in many forms, such as capsules, gummies, powders, and tablets. Some manufacturers add nutrients to drinks and energy drinks. Always check with a healthcare provider before starting a new supplement. The Food and Drug Administration does not check whether supplements are effective or safe before they hit the market.

You might need supplements if you cannot meet your daily intake goals of certain minerals and vitamins through your diet alone. Still, many people get enough minerals and vitamins from a nutrient-rich diet.

"For the average healthy person, you probably don't need a multivitamin, multimineral supplement,"Beth Kitchin, PhD, RDN, an assistant professor in the department of nutrition sciences at the University of Alabama at Birmingham, toldHealth. "You certainly don't need a lot of additional supplements on top of that."

There's a lack of evidence showing whether supplements help prevent or treat health conditions. For example, a study published in 2018found that regular supplement use has no net effect on heart health or the risk of early death. The research team's findings were consistent for multivitamins, calcium, and vitamins C and D, all of which people have touted for heart health.

"We found a surprising neutrality of effects,"David Jenkins, MD, PhD, lead author of the 2018 study, toldHealth. "In other words, it didn't seem to do anything."

The 2018 study only looked at heart problems and early death. Some supplements might benefit your bone, eye, and skin health. For example, calcium and vitamin D help prevent bone loss, especially in people with a high risk of osteoporosis. Pregnant people benefit from taking folic acid, which helps minimize the risk of birth defects.

Vitamins With Potential for Overdose

You might develop adverse effects—as well as spend too much money—if you take too many supplements. Some minerals and vitamins can build up in your blood over time and raise your risk of an overdose. An overdose might happen by accident. Some manufacturers fortify foods and drinks with nutrients, so you may not realize how much you consume.

"You really can't get toxic doses of nutrients through food, but you can absolutely get toxic doses through supplements," said Kitchin. "We've learned a very important lesson, in that when we isolate these nutrients out of food and put them in super-high doses, we may have some unintended consequences."

Any one nutrient can be toxic in excess amounts, though B vitamins and vitamin K do not usually cause toxicity. Some of the most severe risks of an overdose come from calcium and iron supplements. For example, too much calcium in your blood or urine might increase your risk of heart disease and prostate cancer. An iron overdose might cause coma or low blood pressure and damage your intestines and liver.

Other vitamins with a potential for overdose include:

• Vitamin A:Taking too much vitamin A might lead to coma and death in severe cases and harm pregnant and breastfeeding people. Excess vitamin A may also harm the fetus during pregnancy and cause abnormal development of the eyes, heart, lungs, and skull.
• Vitamin D:Vitamin D boosts how much calcium your gut absorbs. As a result, you might have too much calcium in your blood or urine.
• Vitamin E:Excess vitamin E might increase the risk of hemorrhagic stroke, or sudden bleeding in the brain.

The Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine (NASEM) has established tolerable upper intake levels (ULs) for many minerals and vitamins. The FNB has not established ULs for vitamin K since the toxicity risk is low.

ULs are how much of each nutrient you can take without harming your health. Your UL for any one nutrient might depend on your age.

Here are the ULs for some of the most common supplements for males and females aged 0 months to 71 years and older, regardless of whether you are pregnant or breastfeeding: