Do Multivitamins Help or Harm Your Health?

According to a new study published in JAMA Network Open by Erikka Loftfield and researchers at the National Institutes of Health’s National Cancer Institute, daily multivitamin use is associated with a higher mortality risk compared to non-users. This massive study with over 390,000 adults showed that there is no clear justification for routine use of multivitamins in healthy adults. Rather, multivitamin users appear to be slightly more likely to die than their non-user counterparts.

Background

Supplementation is justified and evidence-based in some circumstances, such as folate supplementation in pregnancy. But overall, the benefits of multivitamin supplements have been questioned for years. While many take multivitamins as “insurance” against a diet that may not be optimal, there is a lack of evidence showing that general multivitamins provide any meaningful benefits.

Nearly one in three Americans takes a daily multivitamin. The primary motivation for this is maintaining or improving health. However, studying the effectiveness of multivitamins in the “real world” is complicated by the healthy user effect – those that take vitamins typically eat healthier, exercise more, and smoke less. There is also the sick user effect which may play a factor – in that patients with a diagnosed disease may increase their multivitamin intake because of the perceived benefits.

The Study

The study analyzed three different US populations where there were repeat assessments of use over an extended period, with the tracking of health-related outcomes. Participants in this analysis were drawn from the National Institutes of Health–AARP Diet and Health Study (NIH-AARP) cohort, the PLCO Cancer Screening Trial cohort, and the Agricultural Health Study (AHS) cohort. After data quality exclusions and exclusions based on chronic diseases, the final population available for analysis was 390,124 adults, with trial entry as early as 1993. In all three trials, participants were asked at initiation and in follow-up about their supplement use. Those that answered “Yes” were asked about frequency of multivitamin use using predefined categories.

Results

In all three cohorts, multivitamin daily users vs nonusers were comparable with a few differences: Participants who used multivitamins were more likely to use individual supplements, have lower BMI and better diets compared to non-users. Multivitamin use didn’t vary significantly by race/ethnicity or family history of cancer. Daily multivitamin use was associated with a higher mortality risk compared to non-users (Hazard ratio 1.04, 95% confidence interval 1.02-1.07). There were no differences in mortality when looking at heart disease, cancer, and cerebrovascular mortality.

Conclusion

There’s no question that vitamins play a critical role in health. Supplementation is not always beneficial though – look to the harms caused by beta-carotene supplements or vitamin E supplements. Given how regularly Americans take multivitamins, it’s important to understand their health effects. This massive study with over 20 years of follow-up has showed that there is no clear justification for routine use of multivitamins in healthy adults. Rather, multivitamins users appear to be slightly more likely to die than their non-user counterparts. This reinforces the need for targeted, science-based supplementation when the evidence supports it, rather than indiscriminate multivitamins.

Disclaimer

All views expressed are personal views alone, and do not represent the opinions of any current or former employers, or any organizations that the author may be affiliated with. All information is provided for discussion purposes only, and should not be used as a replacement for consultation with a licensed and accredited healthcare professional.

Originally Post From https://sciencebasedmedicine.org/no-benefit-to-daily-multivitamin-use/

“Daily Multivitamin Use: No Benefit, Says Science-Based Medicine”