How useful are vitamins? This is what new research has to say

Vitamins are shown in this file photo. (drflet / iStock.com)

In the hopes of staying healthy, many people turn to multivitamins as time goes on, hoping the right concoction will help to stave off heart disease or cancer — but according to new research, vitamins and supplements may not be doing much for the average adult.

Researchers at Northwestern Medicine in Illinois, U.S. have found that unless you are pregnant or using supplements to replace a deficiency on a doctor’s advice, vitamins are largely wasted on those who are otherwise healthy, according to a review of 84 studies.

“Patients ask all the time, ‘What supplements should I be taking?’” Dr. Jeffrey Linder, chief of general internal medicine in the department of medicine at Northwestern University Feinberg School of Medicine, said in a press release.

“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.”

Nearly half of all Canadians had used at least one nutritional supplement within the last month in 2015, according to Statistics Canada, with around two thirds of women in their 50s and up reporting that they had taken at least one in the last month.

For this new paper, researchers looked at studies assessing the benefits of various multivitamins, supplements and combinations of these, and published their results in an editorial in the journal JAMA on Monday.

The desire to use vitamins and supplements makes sense, the editorial states, as many of these products have “antioxidative and anti-inflammatory effects” that could, in theory, decrease the risk of cardiovascular disease and cancer risk.

But when you look at the current evidence, researchers say, there isn’t enough support to make it reasonable for the average adult to be buying these products consistently, as when there is a measurable impact, it is small. Researchers gave the example of a 65-year-old woman taking multivitamins for five to 10 years and seeing only a 0.5 per cent decrease in her already low risk of mortality within the next nine years.

Fruits and vegetables contain vitamins in a mix that works together to create those health benefits, the editorial explained, and the vitamins by themselves don’t have quite the same impact.

However, this doesn’t mean that they’re never helpful. For some people, they can be essential.

“In the right circumstances, supplements have health benefits,” the editorial stated. “Vitamin and mineral deficiencies cause myriad illnesses. For individuals who are or may soon become pregnant, 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.”

Co-author Dr. Natalie Cameron, an instructor of general internal medicine at Feinberg, added in the release that prenatal vitamins are one of the most common ways that those who are pregnant receive vitamins such as folic acid.

“More data is needed to understand how specific vitamin supplementation may modify risk of adverse pregnancy outcomes and cardiovascular complications during pregnancy,” she said.

The research supports new recommendations made by the U.S. Preventive Services Task Force, an independent body of experts that provides health care recommendations. The USPSTF advisory, published Monday, states that they recommend “against the use of beta carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer,” and have found insufficient evidence for the benefits of multivitamins or any combination of multivitamins and supplements in relation to preventing these two conditions.

They stated specifically that there is no sign that beta carotene or vitamin E helps ward off cardiovascular disease or cancer.

“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 said.

He added that supplements in particular can be a distraction from actual interventions that could help a patient cut down on cancer or heart disease risk.

“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.”

Researchers included 52 new studies in their review that came out since USPSTF last released recommendations in 2014.

The authors pointed out that while many see supplements as “at worst, benign preventive products,” they are not well regulated, and can be a distraction from actually productive interventions in diet and exercise.

“The substantial marketing budget of the supplement industry generates interest, attention, and billions of dollars in revenue,” the study pointed out.

In Canada, while supplements, vitamins and herbal remedies are classed as “Natural Health Products” (NHPs) according to Health Canada, and must be licenced and regulated, a federal watchdog found in 2021 that there were significant gaps in the oversight of manufacturing and regulating for many products.

Health Canada, in response to this audit by the Commissioner of the Environment and Sustainable Development, is proposing regulatory amendments to improve labelling and address risk levels, with the first changes slated to be suggested this year.