CHICAGO - For adults who are generally healthy and not pregnant, multivitamins and dietary supplements may be a waste of money, according to a nationwide panel of experts in disease prevention and evidence-based medicine.
The United States Preventive Services Task Force updated its recommendation on the use of certain multivitamins and supplements based on a review of 84 studies, including 52 new studies since its last recommendation in 2014.
The review examined vitamins A, B, C, D and E, beta carotene, calcium, folic acid, magnesium, selenium, zinc and other multivitamins. It found "insufficient evidence" that taking multivitamins, paired supplements, or single supplements can help prevent cardiovascular disease, cancer, and death in otherwise healthy, non-pregnant adults.
Both heart disease and cancer are the top two leading causes of death in the U.S.
Specifically, the task force recommends against taking beta-carotene supplements because of a possible increased risk of lung cancer and does not recommend taking vitamin E supplements because it has no benefit in reducing the likelihood of death, cardiovascular disease, or cancer.
"Vitamin and mineral supplementation provides little to no benefit in preventing cancer, cardiovascular disease, and death... Data were absent or insufficient to draw conclusions for any of the B vitamins, iron, zinc, or magnesium," the task force concluded in its report.
‘If these were really good for you, we’d know by now’
"Patients ask all the time, ‘What supplements should I be taking?’ They’re wasting money and focus thinking there has to be a magic set of pills that will keep them healthy when we should all be following the evidence-based practices of eating healthy and exercising," Dr. Jeffrey Linder, chief of general internal medicine in the department of medicine at Northwestern University Feinberg School of Medicine, said in a statement.
Linder and fellow Northwestern Medicine scientists wrote an editorial that was also published on June 21 in JAMA that supports the task force’s new recommendations.
"The task force is not saying ‘don’t take multivitamins,’ but there’s this idea that if these were really good for you, we’d know by now," Linder continued. "The harm is that talking with patients about supplements during the very limited time we get to see them, we’re missing out on counseling about how to really reduce cardiovascular risks, like through exercise or smoking cessation."
More than half of U.S. adults take dietary supplements as a way to improve or maintain overall health, and the use of supplements is projected to increase, Linder and colleagues wrote in the editorial. In 2021, close to $50 billion was spent on vitamins and dietary supplements in the U.S., they added.
The editorial noted how eating fruits and vegetables is associated with decreased cardiovascular disease and cancer risk, so it’s reasonable to think certain vitamins and minerals could be extracted and packaged into a convenient pill.
But they argue that whole fruits and vegetables "contain a mixture of vitamins, phytochemicals, fiber, and other nutrients that probably act synergistically to deliver health benefits." In isolation, micronutrients may act differently in the body than when naturally packaged with a host of other dietary components, they wrote.
In the right circumstances, Linder noted how supplements can have health benefits. This includes those who are pregnant, or those with a vitamin deficiency who can benefit from calcium and vitamin D, which have been shown to prevent fractures and potential falls in older adults.
New guidelines do not apply to those who are pregnant
The task force’s new guidelines do not apply to people who are pregnant or trying to get pregnant, JAMA editorial co-author Dr. Natalie Cameron, an instructor of general internal medicine at Feinberg, said in the statement.
For pregnant individuals, folic acid is recommended to prevent neural tube defects, and iron is recommended to prevent preterm birth and low birth weight, as well as improve fetal brain development.
"Certain vitamins, such as folic acid, are essential for pregnant women to support healthy fetal development," Cameron said. "The most common way to meet these needs is to take a prenatal vitamin. More data is needed to understand how specific vitamin supplementation may modify risk of adverse pregnancy outcomes and cardiovascular complications during pregnancy."
Recent research from Northwestern has also found most women in the U.S. have poor heart health prior to becoming pregnant. Cameron said working with patients to optimize cardiovascular health prior to pregnancy is an important component of prenatal care, in addition to discussing vitamin supplementation.
This story was reported from Cincinnati.