Millions of Americans take multivitamins to prevent disease — but here’s why they shouldn’t

Chew on this — a new study finds that millions of Americans are taking multivitamins to prevent disease even though “there is little health rationale” for them.

In fact, daily multivitamin use was associated with a 4% higher risk of death than nonuse, according to research published Wednesday in the journal JAMA Network Open.

“Refocusing nutrition interventions on food, rather than supplements, may provide the mortality benefits that multivitamins cannot deliver,” National Cancer Institute researchers wrote in their findings. “Vegetables, fruits, legumes, and cereal grains are staples in areas of remarkable longevity.”

Researchers asked 390,000 healthy Americans were about their multivitamin consumption and divided them into three groups — nonusers, occasional users and daily users.

The study authors tracked them for two decades, with nearly 165,000 deaths occurring during the follow-up period. The researchers determined that taking a multivitamin did not lower the risk of dying from cancer, heart disease or cerebrovascular diseases.

The results were adjusted for factors including race and ethnicity, education and diet quality.  

“We did not find evidence to support improved longevity among healthy adults who regularly take multivitamins,” the researchers said. “However, we cannot preclude the possibility that daily [multivitamin] use may be associated with other health outcomes related to aging.”

The study authors noted that one in three US adults take multivitamins typically to prevent disease or to improve health.

Still, their popularity has appeared to wane amid mixed evidence about their benefits.

The US Preventive Services Task Force determined in 2022 that vitamin and mineral supplementation offers “little or no benefit” in preventing cancer, cardiovascular disease and death. There was limited evidence of a possible small benefit for lung cancer cases.

There were some limitations to the new study, including that participants may not have accurately reported their multivitamin use and people with a history of cancer and other chronic diseases were excluded.

The researchers hypothesized that people who use multivitamins may have healthier lifestyles, while sicker patients may be more likely to increase their use of multivitamins.

The researchers did say some supplements offer benefits.

• Beta-carotene, vitamins C and E, and zinc have been credited with slowing the progression of age-related macular degeneration, an eye disease.
• Multivitamins have been shown to enhance memory and slow cognitive decline in older people.
• Multivitamins may help bariatric surgery patients.
• Products that feature vitamins B12 and D can help reduce deficiencies of those vitamins.
• Folate supplements in pregnancy can help prevent serious birth defects.