Supplements
Clarissa Chan, PharmD
In June 2022, the U.S. Preventive Services Task Force (USPSTF) updated its 2014 recommendations to state that, for most vitamin, mineral, and multivitamin supplements, there is not enough evidence to recommend for or against taking them to prevent CVD or cancer.
However, there is strong evidence to show that two vitamins—vitamin E and beta-carotene—should not be taken to prevent these conditions.
Studies suggest that there is no benefit to taking vitamin E, and that beta-carotene can be harmful, said John Wong, MD, one of the task force members and a primary care clinician in the Department of Medicine at Tufts Medical Center.
Beta-carotene increases the risk of lung cancer
Evidence shows that beta-carotene can be harmful because it increases the risk of lung cancer in people who are already at risk, such as those who smoke, previously smoked, or have been exposed to asbestos.
“The use of beta-carotene also increases the risk of dying from cardiovascular disease and may increase the risk of death overall or all-cause mortality,” said Chyke Doubeni, MD, MPH, chief health equity officer at Ohio State University Wexner Medical Center. “The estimates of increased risk were in the order of 6% for death from any cause, 10% for death from CVD, and 18–28% for risk of dying from lung cancer.”
Anyone who is at increased risk for lung cancer should discuss which supplements to take with a health care professional, said Wong.
Recommendation limitations
This USPSTF recommendation applies to healthy adults who do not have known or suspected nutritional deficiency or special nutritional needs.
It does not apply to children, people who are pregnant or may become pregnant, or those who are chronically ill or hospitalized.
People who are food insecure may not have sufficient quantity or quality of food and may have nutritional deficiencies, according to USPSTF.
Someone who has a nutritional deficiency may receive a specific vitamin or mineral to replace what is deficient or lost, such as in the case of iron deficiency.
“It is unclear to me that studying people who are food insecure would address the gaps given substantial heterogeneity in such groups,” said Doubeni. “However, the ideal may be to conduct studies in populations that do not currently have a high prevalence of use of vitamins and minerals—that may be difficult to achieve.”
There is strong evidence to support the fact that the disproportionately high rates of CVD and cancer in Black and American Indian/Alaskan Native people are due to the long history of social and economic disadvantages in those groups, and structural and systemic barriers to care in the United States.
Stronger evidence is needed to know whether the use of vitamins and minerals (besides beta-carotene and vitamin E) provide more benefit than harm. “It is critically important for future studies to include adequate numbers of groups in the U.S. who experience disproportionate rates of CVD and cancer, particularly Black and Indigenous people. Inclusiveness in research should be a national priority,” said Doubeni.
How pharmacists can help
Pharmacists have a critical role in educating people about the use of vitamin and mineral supplements. “I suspect many people would ask about using supplements for improved general health, prevention, and to live longer,” said Doubeni. “People should be advised to eat a healthy and balanced diet, be physically active, maintain a healthful weight, not smoke, and use alcohol only in moderation.”
In addition to the USPSTF recommendations, people should be told that excessive amounts of some supplements, such as vitamins A and D, could be harmful, said Doubeni.
“Pharmacists [should] ask about vitamins and mineral supplements patients may be taking to assess drug interactions,” said Wong.
If they have been advised to take supplements for a medical reason, such as nutritional deficiencies, they should follow the advice of their clinician(s) and discuss any concerns with their clinician(s) to make an informed decision on whether to continue or discontinue taking them, said Doubeni. And those who believe they have a health condition that could benefit from vitamins and/or minerals, or people who are pregnant or could become pregnant, should follow the advice of their clinician, he noted.
USPSTF’s recommendation for healthy diet and exercise, and other task force recommendations, are available through the Prevention TaskForce app, said Wong. In a separate recommendation, the Task Force recommends that everyone who is planning to or could become pregnant should take folic acid. ■
CVD Prevention: USPSTF recommendation summary
USPSTF made several important changes earlier this year to the recommendation on aspirin use to prevent CVD:
- People in their 60s and older should no longer consider starting to take aspirin to prevent a first heart attack or stroke. New evidence shows that the harms cancel out the benefits. (Grade D)
- Taking aspirin may benefit some people in their 40s. For the first time, the Task Force recommends that adults in their 40s talk to their clinician to see if they are at higher risk of developing heart disease or stroke, and if so, whether starting to take aspirin is right for them. (Grade C)
- The latest research also shows a closer balance of benefit and harm than previously known for adults in their 50s. They should also talk with their clinician about whether or not to start taking aspirin. (Grade C)
As for statin use to prevent cardiovascular disease, USPSTF released a draft recommendation statement earlier this year that is consistent with the prior final recommendation statement in 2016. USPSTF is currently reviewing public comments on that draft, which held that:
- People between 40 and 75 years old who are at high risk should take a statin. (Grade B)
- People between 40 and 75 years old who are at increased risk, but not at high risk, may benefit from statins. They should talk with their clinician and decide together if taking a statin is right for them. (Grade C)
- More research is needed on whether people 76 years or older should take a statin to prevent a first heart attack or stroke. (I Statement)
Grade definitions: A, strongly recommended; B, recommended; C, no recommendation; D, not recommended; I, insufficient evidence to make a recommendation.