Research studies do not support the idea that taking multivitamins improve longevity but there is some value to supplements.TONY CENICOLA/The New York Times News Service
According to a new major study, taking a daily multivitamin does not lower the risk of dying from cancer, heart disease or stroke.
These new findings, published June 26 in the journal JAMA Network Open, are hardly surprising. After all, this isn’t the first study to arrive at this conclusion.
In 2022, after reviewing 84 published studies, the U.S. Preventive Services Task Force concluded there was no evidence that multivitamins helped guard against cardiovascular disease or cancer in generally healthy people.
The latest research, however, addresses some of the weaknesses of previous studies. Yet multivitamins still came up short at improving longevity.
What to know about the latest study, plus better reasons to consider taking a multivitamin.
What is a multivitamin exactly?
The name “multivitamin” is a bit of a misnomer since most products contain a broad spectrum of vitamins and minerals, often in doses that don’t exceed official daily requirements.
For the current study, multivitamins included “anti-stress” supplements, vitamin B complex supplements, “one-a-day” multivitamin and mineral supplements (the most commonly used) and therapeutic multivitamins (e.g., for pregnancy, macular degeneration, bone health, etc.).
About the latest research
For the new study, researchers at the U.S. National Institutes of Health evaluated the association between multivitamin use and leading causes of chronic disease-related death, cancer and cardiovascular disease.
To do so, they combined and analyzed data from three previous large and geographically diverse U.S. studies involving a total of 390,124 adults, ages 18 to 74.
Participants, free of a major chronic disease at the outset of each study, were followed for 20 to 27 years.
Multivitamin use was measured at the start of the study and repeatedly throughout. Participants were categorized as non-users, non-daily users or daily users.
During the study period, 164,762 people died; 57 per cent of deaths were attributed to cancer, heart disease or stroke.
Overall, daily multivitamin use – compared to non-daily use – was not associated with a lower risk of all-cause mortality.
The researchers found no evidence that daily multivitamin use lowered the risk of dying from cancer, heart disease, stroke or other conditions that affect blood flow to the brain.
Strengths, limitations
Previous studies have turned up inconsistent findings for multivitamins reducing cardiovascular disease, cancer or mortality.
One reason may be that people who take a daily multivitamin are more health conscious than those who don’t.
For example, daily multivitamin users may eat a healthier diet and exercise more often than non-users. They may have lower rates of smoking and obesity.
It’s also possible that people don’t start to take a daily multivitamin until they’re older or once they develop a chronic illness.
The latest study is notable because it addressed these concerns.
The researchers collected detailed information on demographics and lifestyle factors.
To arrive at the results, they accounted for factors such as age, ethnicity, education level, smoking status, body weight, physical activity, alcohol intake, diet quality and family history of cancer.
The study’s main limitation is its observational nature. The findings show an association; they don’t prove a relationship exists between multivitamins and mortality.
Why you should consider a multivitamin
A daily multivitamin can offer health benefits that don’t involve longevity.
Certain multivitamin formulations, for instance, have been shown to slow the progression of age-related macular degeneration.
Multivitamin supplements can also help prevent nutrient deficiencies following bariatric surgery.
And taking a multivitamin with folic acid before and during pregnancy helps prevent serious neural tube defects in developing babies.
For people who follow a low calorie diet, eat a narrow range of foods or follow a vegan diet, a daily multivitamin can help meet daily nutrient requirements.
Taking a daily multivitamin is also an important way some people get enough vitamin B12, vitamin D and/or iron.
Bottom line
To live longer and be in good health, focus on your overall diet.
Diet quality is a leading indicator of chronic disease risk and all-cause mortality.
A healthy dietary pattern that includes fruits and vegetables, whole grains, nuts and pulses (beans and lentils) is associated with adding healthy years to one’s life. A multivitamin can’t fix a poor diet.
Focus, too, on maintaining (or building) muscle mass and strength as you age by engaging in resistance training and consuming adequate protein.
Sarcopenia, the progressive loss of muscle mass, strength and function, is tied to a greater risk of falls and fractures, frailty, hospitalization and mortality.
Take a multivitamin to bridge nutrient gaps in your diet or for a reason deemed important by your health care provider.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD