Are you taking a multivitamin? New research says it's not helping you live longer — but your supplements may still have benefits.

For years, there has been a big debate in the nutrition world about whether most people need a multivitamin. Despite this, up to a third of all Americans take a multivitamin — and lowering the risk of developing diseases is a big motivation. But new research suggests that taking a multivitamin may have no impact on how long you live, making this common supplement somewhat pointless for many.

The study, which was published in JAMA Network Open, analyzed data from three cohort studies in the U.S., following more than 390,00 people for up to 27 years. Each study participant reported information on a number of health factors, including whether they took a multivitamin.

After crunching the data, the researchers found that using a multivitamin wasn’t linked to a lower mortality risk from any cause, no matter how long a person had been taking the multivitamin. “Multivitamin use was not associated with a mortality benefit,” the researchers concluded. “Still, many U.S. adults report using multivitamins to maintain or improve health.”

It’s easy to read that and think it’s time to finally stop investing in multivitamins. But dietitians say the reality is a little more complicated. Here’s the deal with multivitamins and health, plus why experts say there still may be value in taking your vitamins.

What do dietitians think?

It’s important to point out that a scientific commentary article was also published in JAMA to go with the study mentioned above. In it, several dietitians noted that there’s more to taking a multivitamin than whether you end up dying from a disease. Supplements that contain beta carotene, vitamins C and E, and zinc are linked with slowing the progression of age-related macular degeneration, an eye disease that interferes with your central vision, they wrote. And, in older adults, taking a multivitamin is linked with better memory and slower cognitive decline.

Multivitamins can also help offset deficiencies and provide important nutrients, including folate supplementation in pregnant women to lower the risk of neural tube defects in infants, the authors said.

Sonya Angelone, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics, tells Yahoo Life that the study is “misleading.”

“Most people do not take multivitamin supplements to reduce mortality,” she says. “And health professionals who understand the use or appropriate supplementation, also do not recommend multivitamin supplements to reduce mortality.”

While multivitamins may not help you live longer, Angelone says they may benefit your “health span,” meaning the portion of your life when you’re in good health. “Many people benefit from supplementation of certain nutrients,” Angelone says. “Calcium, vitamin D and K2 can decrease fracture risk, which may not decrease mortality but will improve health and mobility.”

Vitamin D also can help support the immune system and help people with conditions like asthma and other inflammatory conditions, she says. “B vitamins may benefit those taking certain medications which lower absorption of B vitamins,” Angelone continues. “Also, many people have gene variants that decrease the absorption, digestion, transport and metabolism of certain nutrients. These individuals may benefit from taking certain supplemental nutrients.”

Erikka Loftfield, study co-author and an epidemiologist at the National Cancer Institute, tells Yahoo Life that "it's possible" that daily multivitamin use has an impact on other conditions and symptoms associated with aging — it just needs to be studied.

But there is a definite health halo surrounding multivitamins, Deborah Cohen, a doctor of clinical nutrition and associate professor in the department of Clinical and Preventive Nutrition Sciences at Rutgers University School of Health Professions, tells Yahoo Life. “For some, taking a multivitamin may be perceived as improving their quality of life, in that they perceive taking a multivitamin as giving them a health advantage, a form of insurance against disease,” she says. But Cohen points out that “there are many people who take multivitamins and then eat very unhealthy diets.”

Dietitians generally recommend doing what you can to get your nutrients from food first, but not everyone can do this, Karen Ansel, a registered dietitian-nutritionist and co-author of Healthy in a Hurry, tells Yahoo Life. “Over the years, my thinking on the subject has really changed,” she says. “For years, I believed that eating lots of healthy foods could provide all the nutrients I needed. But as I started to develop low iron because I don’t eat much meat, and realized I could also benefit from some extra vitamin B12 and vitamin D, I decided a multi could provide all of these in one shot.”

That doesn’t mean everyone needs a multivitamin, or that all multivitamins are created equal. “Many multivitamins provide excessive amounts of vitamins and minerals,” Ansel says.

Who can benefit from a multivitamin?

It depends. It’s important to point out that supplements like multivitamins are part of a largely unregulated industry. As a result it can be difficult to know if what companies claim is in a multivitamin is actually inside. (That’s why dietitians generally recommend only purchasing from a reputable brand, and ideally one that does third-party testing.)

But even high-quality multivitamins may not be needed. “For most people, the truth is that a multivitamin is unnecessary if one consumes a plant-based diet that includes a lot of fruits, vegetables, legumes and whole grains,” Cohen says. “But for [a lot of people] that is much, much too difficult, and for folks living in the U.S., taking a pill is [considered] so much easier.”

With that, Angelone says that many people can benefit from taking a multivitamin or other nutritional supplements. “The key is knowing what you need and how much you need,” she says. Her advice: Consult with a health professional, like a primary care physician or dietitian who can test your blood and nutrient levels to see if you may need additional support. “Then, appropriate recommendations can be made for you,” she says.

If your health care professional recommends a multivitamin, Cohen says it’s important to remember that a higher price tag doesn’t necessarily mean that a multivitamin is better. “Some are inexpensive and some are quite expensive,” she says. “The higher the cost or price does not necessarily mean that it is better.”

Ansel also suggests choosing a multivitamin with nutrients that are no more than 100% of the recommended daily allowance. “Any amount over what you need is urinated out — so money literally down the drain,” Cohen points out.

Ultimately, it’s best to consult a health care professional and take things from there. While nutritionists say multivitamins don’t need to be vilified, they also agree that not everyone needs one.