Taking a daily multivitamin does not help people live longer and may even increase the risk of early death, according to a major study.
US researchers analyzed health records from nearly 400,000 adults without major diseases to see if daily multivitamins reduced their risk of death over 20 years. Instead of living longer, those who took multivitamins were slightly more likely to die during the study period. The researchers concluded that “multivitamin use to improve longevity is not supported.”
Almost half of UK adults and a third of US adults take multivitamins regularly, but researchers have questioned their benefits and warned they could be harmful. For instance, while natural beta-carotene protects against cancer, beta-carotene supplements can increase the risk of lung cancer and heart disease. Iron in multivitamins can also cause iron overload, raising the risk of cardiovascular disease, diabetes, and dementia.
Dr. Erikka Loftfield and her team at the National Cancer Institute studied data from three major US health studies launched in the 1990s, involving 390,124 healthy adults tracked for over 20 years. They found no evidence that daily multivitamins reduced death risk and observed a 4% higher mortality risk among users initially.
Dr. Neal Barnard of George Washington University noted that while vitamins are useful in specific cases, such as preventing scurvy or slowing macular degeneration, multivitamins generally do not improve longevity. Instead, he emphasized the importance of a healthy diet rich in natural foods, which provide a broad range of nutrients.
Dietitian Duane Mellor added that while supplements can’t fix an unhealthy diet, they can help cover key nutrients, like vitamin D in winter or vitamin B12 for vegans and vegetarians.