Insufficient evidence for vitamin supplements in prevention of CVD or cancer

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1. In their recent recommendation statement, the U.S. Preventive Services Task Force (USPSTF) states that there is insufficient evidence to assess the benefits and harms of multivitamins in preventing cardiovascular disease (CVD) or cancer.

2. The USPSTF recommends against the use of Vitamin E and beta-carotene supplements in the prevention of CVD or cancer.

Evidence Rating Level: 1 (Excellent) 

Study Rundown: Use of multivitamin supplements is common, but evidence in support of their ability to prevent either CVD or cancer is limited.  In this update to the 2003 recommendation statement, the USPSTF reviewed the evidence of the efficacy of multivitamins and mineral supplements in preventing CVD and cancer among the general population. First, the USPSTF found insufficient evidence for the use of multivitamins in preventing CVD or cancer.  They also found insufficient evidence to assess the benefits or harms of single- or paired-nutrient supplements with the exception of Vitamin E and beta-carotene.  The USPSTF recommends against the use of beta-carotene supplementation, mostly based on two trials that showed an increased risk of lung cancer in high-risk patients.  For Vitamin E supplements, the USPSTF reviewed six trials that overall did not show any improvement in rates of CVD or cancer.  The review found insufficient evidence to comment on the harms of most vitamin supplements. The USPSTF’s recommendations are based on reviews of a small number of randomized controlled trials and cohort studies for each vitamin supplement, and these studies are often limited in the generalizability. Studies that include a wider sampling of the general population are needed to produce more accurate future recommendations. 

Click to read the study in the Annals of Internal Medicine

Relevant Reading: A systematic review of multivitamin-multimineral use and cardiovascular disease and cancer incidence and total mortality 

In-Depth [systematic review]: The USPSTF reviewed evidence found in RCTs and cohort studies to determine whether multivitamin/single-vitamin supplement use had any positive or negative effects on CVD and cancer prevention. The evidence was often insufficient to make any definitive judgments either way, but two notable exceptions to this trend were beta-carotene and vitamin E. Beta-carotene supplementation was found to increase the risk for lung cancer incidence and mortality among current smokers (pooled OR 1.24; 95% CI 1.10 to 1.39). Evidence gathered from six RCTs shows that vitamin E supplementation does not significantly affect the risk for either CVD or cancer.

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