Health benefits
Daily Multivitamins May Not Promote Longevity, Study Finds
A new study from the National Institutes of Health (NIH) has cast doubt on the long-held belief that daily multivitamin supplements contribute to a longer life. Published in the *JAMA Network Open*, the study analyzed data from nearly 400,000 generally healthy adults over a period of more than two decades. The findings suggest that regular multivitamin use does not improve longevity and may even be associated with a slightly higher risk of death.
The research, led by Dr. Erikka Loftfield from the National Cancer Institute, scrutinized the health records of participants who were free from major chronic diseases at the study's outset. Participants, aged between 18 and 74, were divided into three groups based on their multivitamin usage: non-users, non-daily users, and daily users. Over the study period, nearly 165,000 deaths were recorded, with causes ranging from cancer to heart disease and cerebrovascular diseases.
Surprisingly, the study found no evidence that daily multivitamin use reduced the risk of death from any cause. In fact, daily multivitamin users exhibited a 4% higher risk of mortality compared to non-users. This finding aligns with previous research that has questioned the efficacy of multivitamins in preventing chronic diseases and extending life.
Dr. Loftfield and her team accounted for various factors that could influence the results, such as diet quality, physical activity, smoking status, and alcohol consumption. Despite these adjustments, the association between multivitamin use and increased mortality risk remained. The researchers suggest that this could be due to the "sick user effect," where individuals with underlying health issues are more likely to start taking multivitamins in an attempt to improve their health.
The study's findings have sparked a debate among health experts. Dr. Neal Barnard, an adjunct professor at George Washington University, emphasized that while vitamins have specific uses, such as preventing scurvy with vitamin C or supporting eye health with beta-carotene, the overall scientific consensus does not support their role in extending lifespan. "The best approach to nutrition is a balanced diet rich in vegetables, fruits, whole grains, and legumes," Dr. Barnard stated.
Jane Mellor, a registered dietitian and senior lecturer at Aston Medical School, echoed these sentiments, noting that supplements should not be seen as a substitute for a healthy diet. "Multivitamins can help fill nutrient gaps for individuals who struggle to get enough vitamins from food alone, such as vitamin D in winter or vitamin B12 for vegans," Mellor explained. However, she stressed that for the general population, focusing on a nutrient-rich diet is more beneficial.
The study also highlighted the potential risks associated with certain supplements. For example, beta-carotene supplements have been linked to an increased risk of lung cancer and heart disease in smokers, while excessive iron intake from multivitamins can lead to iron overload, increasing the risk of cardiovascular disease, diabetes, and dementia.
Despite the lack of evidence supporting the longevity benefits of multivitamins, they remain popular. Nearly one-third of U.S. adults report taking them regularly, driven by the belief that they can prevent disease and promote overall health. However, the study's authors caution against relying on supplements for longevity benefits and advocate for a diet-based approach to nutrition.
Dr. Jade Cobern, a board-certified physician in pediatrics and general preventive medicine, advised individuals to consult their doctors about their dietary needs and supplement use. "Routine health checkups and discussions with healthcare providers are essential to determine if specific vitamin supplements are necessary based on individual health history and diet," Dr. Cobern recommended.
In conclusion, while multivitamins may offer benefits for certain individuals with specific nutrient deficiencies, the evidence does not support their use for extending life in generally healthy adults. The study underscores the importance of obtaining nutrients from a balanced diet and highlights the need for further research to understand the complex relationship between supplements and health outcomes.