June 30, 2022, 7:10 p.m. Cindy Borgmeyer — The U.S. Preventive Services Task Force on June 21 released a mixed bag of final recommendations on using certain dietary supplements to prevent cardiovascular disease and cancer. Based on a systematic review of available evidence, the task force recommended against using beta carotene or vitamin E supplements for CVD or cancer prevention — a “D” recommendation. In a separate pair of “I” recommendations, task force members said current evidence is insufficient to assess the balance of benefits and harms of using other single or paired nutrient supplements or multivitamin supplements to prevent these health problems.
All three recommendations apply only to community-dwelling, nonpregnant adults. It does not apply to children, people who are pregnant or may become pregnant, or those who are chronically ill, are hospitalized, or have a known nutritional deficiency. It should be noted that the USPSTF separately recommends that all individuals who are planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400-800 µg) of folic acid to prevent certain birth defects.
The full recommendation statement, along with a final evidence review and evidence summary, may be viewed on the task force website. The recommendation statement and evidence report also were published June 21 in JAMA.
All three final recommendations mirror the USPSTF’s 2014 recommendation statement on this topic. The AAFP supported that 2014 statement when it was issued.
“We all want ways to prevent heart disease, stroke, and cancer, so the task force again reviewed the evidence on whether taking vitamins and minerals helps prevent these diseases,” said task force member John Wong, M.D., in a June 21 USPSTF Bulletin. “Unfortunately, based on the existing evidence, the Task Force cannot recommend for or against the use of most vitamins and minerals and is calling for more research.”
Scope of the Issue
CVD and cancer are the two leading causes of death in the United States and, despite declines seen across all age groups in the past two decades, they still account for nearly half of all U.S. deaths each year.
Meanwhile, according to data from the 2011-2014 National Health and Nutrition Examination Survey, slightly more than half of surveyed U.S. adults reported using at least one dietary supplement in the previous month, and nearly one-third reported using a multivitamin-mineral supplement. The most commonly reported reason for using these products is to close dietary nutrient gaps and bolster overall health and wellness, including via their potential anti-inflammatory and antioxidative effects.
To update the existing recommendation statement, the task force commissioned a systematic review of evidence regarding the benefits and harms of vitamin and mineral supplementation in healthy adults to prevent CVD and cancer. Data sources included studies published in MEDLINE, PubMed (publisher-supplied records only, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Embase, between January 2013 and February 1, 2022. All studies included in the previous review were evaluated for inclusion in the current review.
After reviewing 17,459 unique citations and 379 full-text articles, a total of 84 studies were included, 52 of which were newly identified since the previous review. The included studies addressed multivitamins; vitamins A, B3, B6, B12, C, D and E; beta carotene; folic acid; calcium; magnesium; selenium and zinc. The evidence for the B and C vitamins, folic acid, magnesium, selenium and zinc was low, insufficient or absent for all outcomes.
Findings from that review varied considerably by supplement and tracked closely with those the task force had reported previously while developing its draft recommendation statement. Among highlights were the following:
The USPSTF accepted public comment on the draft recommendation statement from May 4, 2021, to June 1, 2021. In response to queries from commenters, the task force specified the doses of beta carotene, vitamin A and vitamin E used in trials reporting harms from these vitamins.
To comments suggesting that people who have chronic conditions or are hospitalized be included in the recommendation, the USPSTF responded by clarifying that its recommendations apply to community-dwelling individuals without known underlying health conditions. People who have an acute or chronic illness may require additional vitamin, mineral or multivitamin supplementation as part of managing their condition, which goes beyond the preventive supplementation practices addressed in this recommendation.
Finally, task force members explained that individuals who experience food insecurity are among the patient populations of specific interest when considering future research to determine whether the effects of vitamin, mineral and multivitamin supplementation on CVD and cancer outcomes differ across populations.
Corey Lyon, D.O., associate professor and associate vice chair for clinical affairs in the Department of Family Medicine at the University of Colorado School of Medicine in Denver, said patients often come to their family physician with questions about vitamins and supplements. “Sometimes the most important guidance we can give patients is when to not take or stop taking medications and supplements that do not provide any benefit,” he told AAFP News.
“These recommendations provide us with more definitive guidance to offer patients that they should not take beta carotene or vitamin E as they do not help prevent cardiovascular disease or cancer and may cause harm.”
However, the research picture remains incomplete, Lyon observed. “There are still gaps in the available evidence with multivitamins and other single nutrient supplements,” he said, “so benefits and harms are not as clear as with beta carotene or vitamin E.
“That means the patient and physician will have to make decisions based on personal goals and shared decision-making with an understanding we don’t have very much evidence to help guide those decisions.”
Still, said Lyon, who also is associate program director for the University of Colorado Family Medicine Residency Program, the value of the task force’s work can’t be overestimated. “In everyday practice and in training, we utilize the USPSTF’s recommendations to help guide the care and inform the guidance we provide patients, especially regarding preventive care.
“Information like this latest recommendation is another resource we use when working with our patients.”
The Commission on Health of the Public and Science will review the task force’s final recommendation statement, final evidence review and evidence summary and will then determine the Academy’s stance on the recommendation.