While we would usually get to this in our weekly Paper Watch, sent to subscribers every Wednesday, a new study on multivitamin use and mortality is getting a lot of media and socials attention today, so we thought we would summarize what it adds to the multivitamin picture, given what we already knew.
The Multivitamin Context: A ~$50b Market With Messy Evidence
Before analyzing the new paper, let's summarize what we already know from research about multivitamin efficacy. There is conflicting evidence from various studies. Some studies suggest potential benefits, such as a reduction in cancer incidence in men (Huang 2006, Fortmann 2013), fewer infections and improved quality of life in individuals with type 2 diabetes (Barringer 2003), and improved micronutrient status in older adults (McKay 2000).
However, other studies have found no significant effects on mortality, cancer risk, or chronic disease risk (Angelo 2015, Park 2011). The overall quality of research on the effects of multivitamins on acute respiratory tract infections is weak, with conflicting results (Cramer 2020). In short, the effectiveness of multivitamins remains inconclusive, and we badly need larger-scale studies to settle the issue.
With that context, enter this new JAMA paper ...
Paper: Multivitamins and Mortality
Practicality (4/5): 🏃♂️🏃♂️🏃♂️🏃♂️
Interest (5/5): 🏃♂️🏃♂️🏃♂️🏃♂️🏃♂️
Summary
Daily use of multivitamins was not linked to longer life expectancy among generally healthy adults. Examining data from over 20 years and nearly 400,000 people, the study found no significant mortality benefit. Essentially, adjusting for confounding factors, people taking multivitamins didn't live longer than those who didn't.
What is the paper's main claim?
- Regular multivitamin use does not reduce the risk of death.
- This conclusion applies across varying causes such as heart disease or cancer.
Are the methods and/or data it uses appropriate and convincing?
- The study used a large sample size of 390,124 participants with over 20 years of follow-up, enhancing the reliability of its findings. It is the largest study of its kind
- The analysis adjusted for factors like diet quality, smoking, and exercise but did not find a meaningful impact from multivitamins on longevity, making the effect size negligible.
- The paper was observational, so it cannot establish causality and risks being confounded. It seems unlikely a large effect size would be missed, but it is worth noting the design.
What do we know now that we didn't know before, if anything?
- This study reinforces prior evidence that indicates no significant mortality benefit from daily multivitamin use in healthy adults.
- The novelty lies in its large-scale, long-term cohort analysis, adding robustness to the existing body of evidence.
What simple and practical thing could a normal person do knowing this?
- Given the lack of mortality benefit, reconsider daily multivitamin use if your primary goal is to live longer, as opposed to, you know, enjoying multivitamin taste.
- Exercise and a balanced diet have better data.
Back next week with our regular updates on the latest papers, simplified and made practical.
