Hoping to stay healthy, many people turn to multivitamins over time, hoping the right mixture will help prevent heart disease or cancer – but new research suggests that vitamins and supplements may not do much for the average adult.
Researchers at Northwestern Medicine in Illinois, USA, have found that unless you are pregnant or use a supplement to replace a deficiency on a doctor’s advice, vitamins are largely lost to those who are otherwise healthy, according to a review of 84 studies.
“Patients keep asking, ‘What supplements should I take?'” Dr. Jeffrey Linder, head of general internal medicine at the Department of Medicine at Northwestern University School of Medicine, said in a statement.
“They lose money and focus on thinking that there must be a magic set of pills to keep them healthy when we all need to follow evidence-based practices for healthy eating and exercise.”
Nearly half of all Canadians used at least one supplement in the last month in 2015, according to Canadian statistics, with about two-thirds of women over the age of 50 reporting taking at least one in the last month.
For this new article, researchers reviewed studies evaluating the benefits of various multivitamins, supplements and combinations of them, and published their results in an editorial in the journal JAMA on Monday.
The desire to use vitamins and supplements makes sense, the editor said, as many of these products have “antioxidant and anti-inflammatory effects” that could theoretically reduce the risk of cardiovascular disease and cancer.
But when you look at the current evidence, researchers say, there is not enough support to make it reasonable for the average adult to buy these products consistently, because when there is a measurable impact, it is small. The researchers gave the example of a 65-year-old woman who took a multivitamin for 5 to 10 years and saw only a 0.5% reduction in the already low risk of death over the next nine years.
Fruits and vegetables contain vitamins in a mix that works together to create these health benefits, the editorial explains, and vitamins alone do not have the same effect.
However, this does not mean that they are never useful. For some people, they can be essential.
“Under the right circumstances, supplements have health benefits,” the editorial said. “Vitamin and mineral deficiencies cause countless diseases. For individuals who are or may become pregnant soon, folic acid is recommended to prevent neural tube defects, and iron is recommended to prevent premature birth and low birth weight, as well as to improve fetal brain development.
Co-author Dr. Natalie Cameron, an instructor in general internal medicine at Feinberg, added in the report that prenatal vitamins are one of the most common ways pregnant women receive vitamins such as folic acid.
“More data is needed to understand how a specific vitamin supplement can change the risk of adverse pregnancy outcomes and cardiovascular complications during pregnancy,” she said.
The study supports new recommendations made by the US Special Services Preventive Services Group, an independent expert body that provides health care recommendations. The USPSTF board, released on Monday, said it recommended “against the use of beta carotene or vitamin E supplements to prevent cardiovascular disease or cancer” and found insufficient evidence of the benefits of multivitamins or any combination of multivitamins and supplements. in connection with the prevention of these two conditions.
In particular, they said there was no indication that beta carotene or vitamin E helped prevent cardiovascular disease or cancer.
“The task force doesn’t say ‘don’t take multivitamins,’ but it has the idea that if they were really good for you, we’d know by now,” Linder said.
He added that the supplements in particular could divert attention from actual interventions that could help the patient reduce the risk of cancer or heart disease.
“The downside is that when we talk to patients about supplements for the very limited time we can see them, we miss tips on how to really reduce cardiovascular risk, such as by exercising or quitting smoking.
The researchers included 52 new studies in their review, which emerged from the last publication of the USPSTF recommendations in 2014.
The authors point out that while many see supplements as “at best, benign preventative products,” they are not well regulated and can be a distraction from truly productive diet and exercise interventions.
“The essential marketing budget of the supplement industry generates interest, attention and billions of dollars in revenue,” the study said.
In Canada, while supplements, vitamins and herbal medicines are classified as “natural health products” (NHPs) by Health Canada and must be licensed and regulated, a federal oversight body found in 2021 that there are significant gaps in the oversight of production and adjustment for many products.
Health Canada, in response to this audit by the Commissioner for Environment and Sustainable Development, is proposing regulatory changes to improve labeling and address risk levels, with the first changes to be proposed this year.
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