Study: Taking multivitamins every day may increase risk of death

Taking multivitamins every day does not help people live longer and may actually increase the risk of early death. A study carried out in the USA came to these conclusions.

US researchers analyzed health data from nearly 400,000 adults without serious long-term illnesses to see if daily multivitamins reduced the risk of death over the next two decades.

Instead of living longer, people who took multivitamins daily were slightly more likely than non-users to die during the study period, prompting the researchers to state that "the use of multivitamins to improve longevity is not supported ".

The global market for supplements is estimated to be worth tens of billions of dollars each year. In the US, one-third of adults use multivitamins in hopes of preventing disease.

While natural food sources of beta-carotene protect against cancer, for example, beta-carotene supplements may increase the risk of lung cancer and heart disease, suggesting that the supplements are missing important components.

Meanwhile, iron, which is added to many multivitamins, can lead to iron overload and increase the risk of cardiovascular disease, diabetes and dementia.

Dr. Erikka Loftfield and colleagues at the National Cancer Institute in Maryland analyzed data from three large US health studies.

All began in the 1990s and collected details on participants' daily multivitamin use. The data covered 390,124 generally healthy adults who were followed for more than 20 years.

The researchers found no evidence that the daily multivitamin reduced the risk of death and reported a 4% higher risk of death among users in the first years of follow-up.

The greater risk of death may reflect the harm that multivitamins can cause or a tendency for people to start taking daily multivitamins when they develop a serious illness.