Vitamins and Minerals: How Much Is Too Much?

Oct. 29, 2021

When you have arthritis, you might be tempted to try anything that could help you feel better. Many people take vitamin and mineral supplements that have been touted for arthritis relief, like calcium or vitamins C, D and E. But it is possible to go overboard and get too much of these or other nutrients — and that could be harmful.

Foods are the best sources of vitamins and minerals, and if you eat a healthful diet, you probably don’t need supplements. But for those with poor diets and people who follow a vegetarian or vegan diet are advised to take particular supplements to ensure they’re getting enough. The same goes for people who have certain medical conditions or take medications that affect how the body produces or metabolizes nutrients.

B-complex vitamins and vitamin C are water-soluble, so if you take too much of them, your body simply flushes out the extra. Vitamins A, D, E and K are fat-soluble should not be taken in high doses because your body stores the excess and, although rare, can cause toxicity. According to the American Association of Poison Control Centers, about 40,000 cases of vitamin toxicity were reported in 2019 and vitamins are among the top 25 substances reported for exposure.

Minerals can be problematic in large doses, too. Premenopausal women are advised in some cases to take iron supplements but continuing them after menopause unless they are needed may lead to an excess. Too much iron can cause symptoms like fatigue, joint pain and depression. An excess of calcium supplements may cause kidney stones and may increase the risk of prostate cancer and heart disease.

Multiple Risks

And there are other risks, too. Because supplements aren’t regulated by the Food and Drug Administration like medicines are, you can never be entirely sure that what’s promised on the label is delivered inside the container.

“There is also a risk of vitamins and minerals interfering with medicines people are taking,” says Laura Gibofsky, a registered dietitian at the Hospital for Special Surgery in New York. For example, vitamins E and K can increase your bleeding risk if you’re already taking a blood thinning medication. Taking vitamin A if you also take the psoriasis drug acitretin (Soriatane) can cause an excess of vitamin A, potentially leading to nausea, dizziness and poor muscle coordination. And calcium supplements may reduce the effectiveness of certain antibiotics.

Ask Your Doctor

Before taking any vitamin or mineral supplement, check that it’s safe for you and doesn’t interact with any of your medications. “Make sure you tell your doctor and take them under the doctor’s guidance,” Gibofsky suggests.

Your doctor might recommend a supplement to correct a nutritional deficiency. If you have rheumatoid arthritis, your doctor may recommend a folic acid supplement to reduce methotrexate side effects. But unless your doctor says otherwise, it’s best to choose supplements that don’t contain more than 100% of the dietary reference intake (DRI) of any particular nutrient.

Count Fortified Foods, Too

It’s hard to overdose on vitamins and minerals from foods alone. However, there’s been a surge in fortified foods, from orange juice boosted with calcium and vitamin D to breakfast cereals or sports drinks packed with extra vitamins, minerals or electrolytes. If you eat a nutrition bar plus a bowl each of fortified cereal and pasta in one day, you could get well more than the recommended amounts of several vitamins and minerals. Prevent overdoing it by eating whole foods and reading labels to find out which packaged foods are heavily fortified.

Bottom line? “There is no magic diet for arthritis,” says Gibofsky. To keep your body as healthy as possible, get as many of your nutrients as possible from whole foods that are not highly processed. “You don’t need to take supplements when a well-balanced diet that includes all the major food groups is sufficient to provide your body with the appropriate vitamins and minerals,” she says.