Updated findings from the Linxian Dysplasia Nutrition Intervention Trial
Mutivitamin supplements are very popular, but research studies looking at their health benefits have provided mixed results. An NCI-sponsored study* was initiated in 1985 to examine if multivitamin supplements reduced esophageal/gastric cardia cancer in individuals with esophageal dysplasia, a condition that increases risk of developing those cancers. The study took place in Linxian, China, a region with very high rates of esophageal and gastric cardia cancer and a poorly nourished population.
Participants (n=3318) were randomized to receive multivitamin supplements or placebo daily for 6 years. The results, which were published in 1993**, indicated that taking multivitamin supplements for 6 years did not decrease cancer incidence or mortality in study subjects.
The participants continued to be followed and a new report, recently published in JAMA Internal Medicine***, revealed findings after 20 years of follow-up. The multivitamin supplements did not have an effect on total mortality or cancer-related mortality in the participants. The supplements were associated with decreases in heart disease deaths in men and subjects greater than 55 years of age. However, the results showed an increase in stroke deaths among women and participants younger than 55 years of age who received multivitamin supplements.
The authors concluded that “during 6 years of multivitamin supplementation and 20 years of postintervention follow-up, we observed no effect of multivitamins on total or cause-specific mortality in a nutrient-deficient population.” They added, “Together with data from previous trials, these results demonstrate little benefit of multivitamin supplementation on mortality in either well- or poorly nourished populations.”
*Project number: N01SC91030
**Li, J-Y., Taylor, P.R., Li, B., Dawsey, S., Wang, G-Q., Ershow, A.G., . . . Blot, W.J. (1993) Nutrition intervention trials in Linxian, China: Multiple vitamin/mineral supplementation, cancer incidence, and disease-specific mortality among adults with esophageal dysplasia. Journal of the National Cancer Institute, 85, 1492-1498.
***Wang, J-B., Abnet, C.C, Fan, J-H., Qiao, Y-L., & Taylor, P.R. (2013) The Randomized Linxian Dysplasia Nutrition Intervention Trial After 26 Years of Follow-up: No Effect of Multivitamin Supplementation on Mortality. JAMA Internal Medicine. doi: 10.1001/jamainternmed.2013.6066.