New Findings on Multivitamin Use and Mortality
A recent large analysis involving nearly 400,000 healthy U.S. adults, followed for over 20 years, has found no association between regular multivitamin use and a lower risk of early death. This cohort study, led by researchers at the National Cancer Institute, was published on June 26, 2024, in JAMA Network Open.
Examining Multivitamin Use and Health
Nearly one in three adults report using multivitamins, primarily to maintain or improve their health and prevent chronic diseases. Despite this widespread use, the benefits and harms of regular multivitamin supplementation remain unclear.
Previous studies on multivitamin use and mortality have produced mixed results, often hindered by limited follow-up times and lack of external validity. In 2022, a major review of data from randomised clinical trials found “insufficient evidence for determining benefits or harms” of multivitamin use due to these limitations.
Study Design and Participant Profile
To explore the relationship between long-term multivitamin use and mortality, researchers analysed data from three large, geographically diverse prospective cohort studies. The studies included the National Institutes of Health–AARP Diet and Health Study, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, and the Agricultural Health Study.
Combined, these cohorts encompassed 390,124 generally healthy adults. They were aged between 50 and 71 years at the start, without a history of cancer or other chronic diseases.
Baseline data on multivitamin use were collected from 1993 to 2001, with follow-up assessments from 1998 to 2004, extending follow-up to up to 27 years. The extensive follow-up period and detailed demographic and lifestyle data. This allowed researchers to address potential biases, such as the “healthy user effect,” where individuals who use multivitamins may generally have healthier lifestyles, and the “sick user effect,” where those in poor health might initiate multivitamin use.
These biases were mitigated by adjusting for variables such as age, sex, race and ethnicity, education, smoking status, body mass index, physical activity, and diet quality.
Key Findings: Multivitamins and Mortality
The analysis revealed that taking daily multivitamins did not lower the risk of death from any cause compared to those who did not take them. Researchers found that the risk of dying during the study period was similar for both groups. Specifically, the hazard ratio (HR) for all-cause mortality among daily users was 1.04 in the first half of the follow-up period and 1.04 in the second half, meaning there was no significant difference in death risk.
The study also looked at specific causes of death, including cancer, heart disease, and cerebrovascular diseases (like strokes). They found no differences in the rates of these diseases between those who took multivitamins and those who did not. In simpler terms, taking multivitamins daily did not help people live longer or avoid these major diseases.
To ensure the results were accurate, researchers adjusted for various factors that could affect health, such as age, sex, race and ethnicity, education level, smoking habits, body weight, physical activity, and diet quality. This careful adjustment helped make sure that the findings were not influenced by these other factors.
Implications for Different Populations
The researchers highlighted the importance of evaluating the effects of multivitamin use on different populations. Particularly those with specific health needs. While this study focused on generally healthy adults, the impact of multivitamins might be different for people with nutritional deficiencies or existing health conditions. For example, individuals with low levels of certain vitamins or minerals might benefit more from supplementation.
Additionally, the potential benefits of multivitamins on other health conditions associated with ageing warrant further investigation. Conditions such as cognitive decline, bone health, and immune function could be influenced by long-term multivitamin use. The current study primarily included middle-aged and older adults. It remains unclear whether the findings apply to younger age groups or those with specific health issues. Researchers suggest that future studies should also consider these subpopulations to provide more targeted health guidance.
Furthermore, the study adjusted for lifestyle factors that can influence health, such as diet, physical activity, and smoking status. However, the interplay between these factors and multivitamin use is complex and may vary among different groups.
For instance, individuals with healthier lifestyles might not experience additional benefits from multivitamins. However, those with poorer diets and lifestyles might see some improvement. This nuanced understanding underscores the need for personalised health recommendations based on individual health profiles and lifestyles.
Impact of Daily Multivitamins on Mortality
This extensive analysis provides valuable insights into the long-term effects of daily multivitamin use. Despite the common belief that multivitamins can enhance overall health and prevent chronic diseases, this study found no evidence to support the idea that regular multivitamin use reduces the risk of early death in generally healthy adults.
Given these results, healthy adults may not need to rely on multivitamins for mortality benefits. Instead, focusing on a balanced diet, regular physical activity, and other healthy lifestyle choices may be more effective for promoting long-term health and well-being. However, for individuals with specific nutritional deficiencies or health conditions, personalised advice from healthcare professionals remains essential.
References
- For healthy adults, taking multivitamins daily is not associated with a lower risk of early death. (2024, June 24). ScienceDaily. https://www.sciencedaily.com/releases/2024/06/240626152205.htm
- Loftfield, E., O’Connell, C. P., Abnet, C. C., Graubard, B. I., Liao, L. M., Freeman, L. E. B., Hofmann, J. N., Freedman, N. D., & Sinha, R. (2024). Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts. JAMA Network Open, 7(6), e2418729. https://doi.org/10.1001/jamanetworkopen.2024.18729
