Editorialists responding to three articles on vitamin and mineral supplementation being published in Annals of Internal Medicine urge U.S. adults to stop wasting their money on dietary supplements. The authors cite the large body of accumulated evidence showing that most multivitamin supplements are ineffective, and some may cause harm.
The message is simple, the authors write.
Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.
The review by the United States Preventive Services Task Force found insufficient evidence that multivitamins prevent cancer, cardiovascular disease, or death.
Long-term multivitamin use does not preserve cognitive function in men
A substudy of a large, randomized, placebo-controlled trial being published in Annals of Internal Medicine shows that long-term use of a daily multivitamin did nothing to slow cognitive decline among men 65 and older.
Multivitamins are the most commonly used dietary supplements in the United States.
A typical daily multivitamin contains a combination of nutrients, such as vitamins A, C, E, ß-carotene and B vitamins, thought to have properties that could help prevent cognitive decline. However, their benefit in preventing age-related cognitive decline is unclear.
Researchers assigned 5,947 male physicians aged 65 and older to take either a daily multivitamin or placebo for 12 years.
After an initial cognitive assessment, the men were tested for cognitive function and verbal memory via telephone interview three additional times at approximately two, six, and 10 years.
The researchers saw no difference in cognitive function between the multivitamin and placebo groups, concluding that there is no benefit for taking a daily multivitamin to prevent cognitive decline.
High doses of multivitamins and minerals do not protect against cardiovascular events following myocardial infarction
Taking high doses of multivitamins and minerals does not protect against secondary cardiovascular events in stable patients receiving appropriate care after myocardial infarction (MI), according to a study being published in Annals of Internal Medicine.
Researchers randomly assigned 1,708 patients aged 50 years or older who had MI at least six weeks earlier and had serum creatinine levels of 176.8 µmol/L (2.0 mg/dL) or less to take either an oral 28 component high-dose multivitamin and multimineral mixture or placebo.
Patient records were reviewed to determine time to death, recurrent MI, stroke, coronary revascularization, or hospitalization for angina. While the multivitamin and mineral regimen was not harmful, it did not seem to reduce cardiovascular events in patients receiving appropriate, evidence-based medical therapy following MI.
The global vitamin industry is huge, with sales last year of $23.4 billion, up 3% from 2011, according to Euromonitor International. Sales of multivitamins specifically rose 2.5% last year, to $14.2 billion. About 40% of Americans reported taking multivitamins or minerals between 2003 and 2006, the most recent data available, according to the Centers for Disease Control and Prevention.