Take a daily multivitamin doesn’t help people live longer and may actually increase the risk of early death, a major study has found.
Researchers in the US analyzed the health records of nearly 400,000 adults with no major long-term illnesses to see if daily multivitamins reduced their risk of death over the next two decades.
Rather than living longer, people who consumed daily multivitamins were marginally more likely than non-users to die in the study period, prompting the government researchers to comment that “multivitamin use to enhance longevity is not supported “.
Almost half of British adults take multivitamins or dietary supplements once a week or more, part of a domestic market worth more than half a billion pounds annually. The global market for the supplements is estimated to be worth tens of billions of dollars each year. In the US, a third of adults take multivitamins in hopes of preventing disease.
But despite the popularity of multivitamins, researchers have questioned the health benefits and even warned that the supplements could be harmful. While natural food sources of beta-carotene protect against cancer, beta-carotene supplements, for example, can increases the risk of lung cancer and heart disease, which suggests that the supplements are missing important ingredients. Meanwhile, iron, which is added to many multivitamins, can lead to iron overload and increases the risk of cardiovascular disease, diabetes and dementia.
For the latest work, Dr Erikka Loftfield and colleagues at the National Cancer Institute in Maryland analyzed data from three large US health studies. All were launched in the 1990s and collected details of participants’ daily multivitamin use. The records covered 390,124 generally healthy adults who were followed for more than 20 years.
The researchers found no evidence that daily multivitamins reduced the risk of death and instead reported a 4% higher risk of death among users in the initial years of follow-up. The increased 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. Details are published in Jama network.
Dr. Neal Barnard, an adjunct professor of medicine at George Washington University and co-author of a commentary published along with the study, said vitamins were helpful in specific cases. Historically, sailors were saved from scurvy by vitamin C, while beta-carotene, vitamins C and E and zinc appear to slow age-related macular degeneration, a condition that can lead to severe vision loss.
It is also the case that vitamins may be beneficial without reducing the risk of early death. A preliminary study in 2022 found evidence of that multivitamins may slow cognitive decline on age, but more research was needed.
Yet “multivitamins overpromise and underdeliver,” Barnard said. “The main point is that the multivitamins don’t help. The science is not there.” Instead of taking multivitamins, we should eat healthy foods, he said, that provide a wide range of micronutrients, macronutrients and fiber while limiting saturated fat and cholesterol.
Duane Mellor, a registered dietician and senior lecturer at Aston medical school, said: “It is not surprising to see that it does not significantly reduce the risk of death.
“A vitamin and mineral supplement won’t fix an unhealthy diet on its own, but it can help cover key nutrients if someone is struggling to get them from food. An example of this could be vitamin D which adults in the UK are encouraged to take as a supplement in winter or vegans and vegetarians who may benefit from a supplement of vitamin B12.”
