Is a daily multivitamin actually worth it?

Taking a daily multivitamin doesn’t lower the risk of dying from cancer, heart disease or stroke, according to a large new study.

The findings of the new study, published June 26 in JAMA Network Open, aren’t surprising — after all, it’s not the first study to reach this conclusion.

In 2022, the U.S. Preventive Services Task Force reviewed 84 published studies and concluded there was no evidence that multivitamins help prevent cardiovascular disease or cancer in generally healthy people.

But the latest research addresses some of the weaknesses of previous studies, but multivitamins still fall short when it comes to extending life.

What you need to know about the latest research, and even more reasons to consider taking a multivitamin.

What exactly is a multivitamin?

The name “multivitamin” is somewhat misleading, as most products contain a broad range of vitamins and minerals in amounts that almost never exceed the official daily requirements.

In the current study, multivitamins included “anti-stress” supplements, vitamin B complex supplements, “once-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

In a new study, researchers from the National Institutes of Health evaluated the association between multivitamin use and the leading causes of death from chronic disease, cancer, and cardiovascular disease.

To do so, the researchers combined and analysed data from three previous large, geographically diverse US studies that included a total of 390,124 adults aged 18 to 74 years.

Participants who had no significant chronic illnesses at the start of each study were followed for 20 to 27 years.

Multivitamin use was measured at the start of the study and repeatedly throughout the study. Participants were classified as nonusers, nondaily users, or daily users.

During the study period, 164,762 people died, 57 percent of which were due to cancer, heart disease, and stroke.

Overall, taking a daily multivitamin was not associated with a lower risk of all-cause mortality compared with not taking it daily.

The researchers found no evidence that taking a daily multivitamin reduces the risk of death from cancer, heart disease, stroke, or other diseases that affect blood flow to the brain.

Strengths and limitations

Previous studies have found inconsistent results on multivitamins reducing cardiovascular disease, cancer, and mortality.

One reason may be that people who take a daily multivitamin are more health conscious than those who don’t.

For example, people who take a daily multivitamin may eat a healthier diet, exercise more, and be less likely to smoke and be obese than those who don’t.

People may also not start taking a daily multivitamin until they are older or develop a chronic illness.

The latest study is notable for addressing these concerns.

The researchers collected detailed information on demographics and lifestyle factors.

To arrive at their results, the researchers took into account factors such as age, ethnicity, education level, smoking status, weight, physical activity, alcohol intake, diet quality and family history of cancer.

The main limitation of this study is that it is observational: although the results show an association, they do not prove that there is a relationship between multivitamins and mortality.

Why You Should Consider a Multivitamin

Taking a daily multivitamin can provide other health benefits beyond longevity.

For example, certain multivitamin preparations have been shown to slow the progression of age-related macular degeneration.

Multivitamin supplements may also help prevent nutritional deficiencies after bariatric surgery.

Also, taking a multivitamin that contains folic acid before and during pregnancy can help prevent serious neural tube defects in the fetus.

For people on low-calorie diets, those who eat a limited range of foods, or those following a vegan diet, a daily multivitamin can help meet daily nutritional requirements.

Taking a daily multivitamin is an important way to ensure you are getting enough vitamin B12, vitamin D, and iron.

Conclusion

To live longer and healthier, focus on your overall diet.

Diet quality is a leading indicator of chronic disease risk and all-cause mortality.

A healthy diet that includes fruits, vegetables, whole grains, nuts, and legumes (beans and lentils) is linked to a longer, healthier lifespan. A multivitamin cannot improve an unhealthy diet.

Also, focus on maintaining (or building) muscle mass and strength as you age through resistance training and adequate protein intake.

Sarcopenia, the progressive loss of muscle mass, strength and function, is linked to increased risk of falls, fractures, frailty, hospitalisation and mortality.

Take a multivitamin to fill any nutritional gaps in your diet, or for any other reason your health care provider determines is important.

Leslie Beck, a Toronto-based practicing dietitian, is Director of Food and Nutrition at Medcan. Follow her on Twitter. Leslie Beck