Supplements may not affect mortality, study says
Researchers looked at data in the National Health and Nutrition Examination Survey from 1999 to 2012, linked to National Death Index mortality data. The cohort study included 30,899 U.S. adults 20 and older who answered questions on dietary supplement use.
The team gathered dietary information through in-person interviews and looked at dietary supplement use in the previous 30 days and nutrient intake from foods and supplements. The outcomes included mortality from all causes, including cardiovascular disease and cancer, according to the study abstract.
During a median follow-up of about six years, 3,613 deaths occurred, which included 945 cardiovascular disease deaths and 805 cancer deaths. The researchers concluded that long-term use of dietary supplements was not associated with mortality outcomes.
Adequate intake at or above the Estimate Average Requirement or the Adequate Intake level of some vitamins, including vitamin A, vitamin K, magnesium, zinc, and copper, was associated with reduced mortality in some cases, including cardiovascular disease, but the associations were restricted to nutrient intake from whole foods. Moreover, excess intake of calcium was associated with increased risk for cancer death, and the association seems to be related to calcium intake from supplements, researchers said.
The researchers say the study has its limitations, and the results from observational data may be affected by residual confounding. Further, self-reported dietary supplement use is subject to recall bias. Regardless, the researchers say use of dietary supplements did not prolong life and, in some cases, were detrimental to health.