1. Multivitamins: Don’t Replace a Balanced Diet <\/p>\n
Multivitamins<\/a> are the most popular supplement for every age group, but little evidence supports their use. Most experts agree that food is the best way to get your vitamins.\n<\/p>\n Some serious side effects of the vitamins found in multivitamins include:\n<\/p>\n 2. Vitamin D: Toxic Calcium Levels <\/p>\n Vitamin D<\/a> helps the body absorb calcium. Taking excessive amounts of vitamin D for months or more can lead to hypercalcemia (toxic calcium levels), leading to symptoms such as:\n<\/p>\n On the most extreme end of the spectrum, vitamin D toxicity<\/a> can cause:\n<\/p>\n Getting vitamin D naturally from sunlight or food, rather than supplements, doesn’t cause this complication.\n<\/p>\n 3. Omega-3s: Immune and Bleeding Complications <\/p>\n Omega-3 fatty acids<\/a> (often found in fish oil pills) can cause severe side effects when taken in high doses. These include:\n<\/p>\n It’s vital to discuss fish oil dosage with your healthcare provider. Experts recommend taking two long-chain omega-3 fatty acids\u2014eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)\u2014in daily doses of no more than 5 grams (g).\n<\/p>\n 4. Vitamin C: Kidney Stones and Drug Interactions <\/p>\n Vitamin C supplements<\/a> are generally safe, and toxicity is rare because it’s a water-soluble vitamin (meaning that excess amounts are eliminated in your urine).\n<\/p>\n However, there is some evidence that high doses of vitamin C can increase the risk of kidney stones<\/a>, especially for men and people already predisposed to kidney stones.\n<\/p>\n Vitamin C supplements can also cause dangerous interactions with certain medications. It’s critical to discuss adding vitamin C to your routine if you take any of the following medications:\n<\/p>\n 5. Calcium: Hardening of the Arteries <\/p>\n Calcium supplements<\/a> may increase the risk of atherosclerosis<\/a> (hardening of the arteries), resulting in symptoms such as:\n<\/p>\n Taking large amounts of calcium can lead to serious health complications. Although the research is somewhat mixed, scientists believe that taking high amounts of calcium may increase the risk of developing:\n<\/p>\n Experts recommend that adults 19\u201350 take no more than 2,500 mg of calcium per day, and for those 51 and over, the upper limit is reduced to 2,000 mg to avoid side effects.<\/p>\n 6. Magnesium: Digestive Upset and Toxicity <\/p>\n Taking high doses of magnesium from supplements<\/a> can cause uncomfortable gastrointestinal side effects, such as abdominal cramping, gas, and diarrhea.\n<\/p>\n When taken in doses over 5,000 milligrams (mg) per day, or by those with poor kidney function, magnesium can lead to toxicity<\/a>, a rare but dangerous occurrence.\n<\/p>\n Symptoms of magnesium toxicity include:\n<\/p>\n Adults 19 and older should not take more than 350 mg of magnesium per day to avoid side effects and reduce the chance of toxicity.\n<\/p>\n 7. Probiotics: Infection for Immunocompromised Individuals <\/p>\n Probiotics<\/a> are live microorganisms that can have a positive effect on your health. Sometimes they’re called “good bacteria.”\n<\/p>\n When taking probiotics, some people can experience side effects, like gas, bloating, and an upset stomach.\n<\/p>\n However, those who are immunocompromised or severely ill should speak to a healthcare provider before using probiotics, as they can result in severe infections, such as:\n<\/p>\n 8. Iron: Dangerous Overdose Risks <\/p>\n Low doses of iron supplements<\/a> can cause various digestive side effects, and very high doses can be dangerous.\n<\/p>\n Although rare, it is possible to overdose on iron supplements. Since 1997, the Food and Drug Administration (FDA) has required that any iron supplements sold in doses higher than 30 mg contain strong warning labels and single-pill packaging.\n<\/p>\n Iron overdose can cause:<\/p>\n Key Takeaways <\/p>\n Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process<\/a> to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.<\/p>\n Centers for Disease Control and Prevention. Dietary supplement use among adults: United States, 2017-2018<\/a>.<\/p>\n<\/li>\n Barnard ND, Kahleova H, Becker R. The limited value of multivitamin supplements<\/a>.\u00a0JAMA Netw Open. 2024;7(6):e2418965. doi:10.1001\/jamanetworkopen.2024.18965<\/p>\n<\/li>\n National Institutes of Health. Vitamin D<\/a>.<\/p>\n<\/li>\n Marcinowska-Suchowierska E, Kupisz-Urba\u0144ska M, \u0141ukaszkiewicz J, P\u0142udowski P, Jones G. Vitamin d toxicity\u2013a clinical perspective<\/a>.\u00a0Front Endocrinol. 2018;9:357018. doi: 10.3389\/fendo.2018.00550<\/p>\n<\/li>\n National Institutes of Health. Omega-3 fatty acids<\/a>.<\/p>\n<\/li>\n National Institutes of Health. Vitamin C<\/a>.<\/p>\n<\/li>\n Cupisti A, Giannese D, D\u2019Alessandro C, et al. Kidney stone prevention: is there a role for complementary and alternative medicine?<\/a>\u00a0Nutrients. 2023;15(4):877. doi:10.3390\/nu15040877<\/p>\n<\/li>\n Anderson JJB, Kruszka B, Delaney JAC, et al. Calcium intake from diet and supplements and the risk of coronary artery calcification and its progression among older adults: 10-year follow-up of the multi-ethnic study of atherosclerosis(Mesa)<\/a>.\u00a0J Am Heart Assoc. 2016;5(10):e003815. doi: 10.1161\/jaha.116.003815<\/p>\n<\/li>\n National Institutes of Health. Calcium<\/a>.<\/p>\n<\/li>\n National Institutes of Health. Magnesium<\/a>.<\/p>\n<\/li>\n National Institutes of Health. Probiotics<\/a>.<\/p>\n<\/li>\n MedlinePlus. Lactobacillus acidophilus.<\/a><\/p>\n<\/li>\n MedlinePlus. Taking iron supplements.<\/a><\/p>\n<\/li>\n National Institutes of Health.\u00a0Iron-deficiency anemia<\/a>.<\/p>\n<\/li>\n National Institutes of Health. Iron<\/a>.<\/p>\n<\/li>\n<\/ol>\n\n
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