Dietary supplement use, nutrient intake and adult mortality in a developed country

There continues to be fierce debate about the value of dietary supplements, particularly in the context of developed nations where nutrient intake should be adequate. The issue has recently been addressed in a prospective cohort study from the USA.  The investigators linked National Health and Nutrition Examination Survey (NHANES ) data from 1999 to 2010, to National Death Index mortality data, examining 30,899 adults aged 20 years or older who answered questions on dietary supplement use. During a median follow-up of 6.1 years, 3613 deaths occurred! These  including 945 cardiovascular deaths and 805 cancer deaths. Ever-use of dietary supplements was not associated with any change in mortality outcomes. Adequate dietary intake of vitamin A, vitamin K, magnesium, zinc, and copper was associated with reduced all-cause or CVD mortality, but the associations were restricted to nutrient intake from foods. Excess intake of calcium was actually associated with increased risk for cancer death. Time to rethink the vitamin & mineral supplements?