June 12, 2023 -- Teresa Stull swears by her multivitamin formulation. Tired of taking pills, the 62-year-old esthetician and business owner in Frederick, MD, turned to a daily liquid formulation for skin health and inflammation. She was attracted to the product (which she also carries for her clients) because of its high absorption rate, the fact that the company shared data on its website, and mostly, its benefits for her skin and overall health.
“I’ve been using it for 6 years,” she said. “It helps the heart with the flaxseed oil, lysine, and all of the inflammation. And the side benefits are healthy skin, healthy nails, healthy hair with the biotin and collagen and how it’s delivered. I feel very balanced.”
Stull is one of the 70% of Americans who take multivitamins daily. But unlike Stull, many lack a clear understanding of their “whys and what’s” -- that is, why am I taking this and what will it do for me? Questions abound whether these supplements do anything to help with disease prevention – namely cancer and heart disease –and many people wonder if they need to take a multivitamin at all.
One reason is that nutritional needs change over one’s lifespan. As people reach middle and older ages, factors like slower metabolism, absorption and chewing issues, chronic low-grade inflammation, as well as multiple prescription medications can lead to vitamin and mineral insufficiencies.
Moreover, the food that we rely on to supply daily nutritional needs is unreliable. Today, commercial farming is plagued by overuse of fertilizers and pesticides and less frequent crop rotation, all practices that affect soil health. When you combine these factors with climate change, it’s likely that the nutritional value of many of the fruits and vegetables that we eat is compromised. It’s even more likely that middle-agers and seniors who swear by healthy diets likely have important gaps in nutrition.
“There’s been a significant deterioration in soil quality over the past 50 years or so and produce is not as nutrient dense as it was,” said Melina Jampolis, MD, an internist, physician nutrition specialist, and author in Valley Village, CA.
The quality of soil also differs from farm to farm.
“When we buy spinach or some other food, we really don’t know how much magnesium, or vitamin K, or calcium is in things grown from ground as they’re dependent on soil and soil varies,” said Christopher D’Adamo, PhD, director of research for the Center for Integrative Health at the University of Maryland School of Medicine.
Prevention vs. Preservation
In 2022, the U.S. Preventive Services Task Force concluded that there was not enough evidence supporting use of supplemental vitamins and minerals – alone, in pairs, or in a multivitamin format – for preventing cancer, heart disease, or related death. The task force also found a link between the use of beta-carotene and an increased risk for lung disease in certain high-risk populations. Vitamin E offered little benefit overall for heart disease or cancer prevention.
So why bother?
“In a perfect world, everyone would get tested for their nutrient status. For example, I need magnesium but not calcium, and I need B1 but not B12. That would be ideal but that’s just not feasible,” explained D’Adamo.
“The reason that multivitamins can be helpful, if you look at the data, is that they can cover the bases.”
They might also help preserve memory as we age, according to two studies conducted by Columbia University and Brigham Women’s Hospital/Harvard University researchers.
The COcoa Supplement and Multivitamin Outcomes Study Web (known as COSMOS-Web) included roughly 3,500 adults older than 60 who were randomly assigned a daily multivitamin or placebo and given a series of cognitive tests annually for 3 years.
“We were testing what I might call learning or immediate memory, our ability to encode or initially store information into memory so that later, we can access it more easily,” said study leader Adam Brickman PhD, professor of neuropsychology in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain.
By the end of the first year, the multivitamin group had significantly greater improvements in memory recall compared to when they started the study and compared to the placebo group.
“We found that the memory effect was sustained on average over the 3 years of this study,” Brickman said.
This improvement was equal to roughly 3 years of age-related memory decline.
The study also reinforced findings of an earlier COSMOS trial (COSMOS-Mind) that showed the effects were more pronounced in people with heart disease, who, across the two trials, had lower baseline memory scores than healthy participants.
“There’s some indication that people with vascular disease and vascular risk factors have lower levels of certain micronutrients than those without. So we think that the multivitamin is supplementing those relative deficiencies,” said Brickman.
There was a third group in the trials who received a cocoa supplement or placebo. A separate analysis showed that people with preexisting flavanol deficiencies who were assigned the cocoa supplement also had improvements in memory function.
- Multivitamins might be the best option, at least for now. In the COSMOS trials, it was unclear if there was a certain element in multivitamins that led to the memory improvements or if flavanols derived from one source are more beneficial than others. It’s also important to consider the potential role that individual vitamins like D3 play in helping preserve bone density and possibly prevent fractures, or the B vitamins (especially B6 and B12) in helping form red blood cells or the body make energy from food. Without widespread personalized nutrition and genetic testing, the one-size-fits-all approach suffices, so long as people take a food-first approach.
“The idea behind multivitamins is that your diet isn’t necessarily perfect so you add the multivitamin to give yourself a little margin of error,” said Alexander Michels, PhD, a research associate at the Linus Pauling Institute at Oregon State University in Corvallis, OR.
He pointed to newly published data from his organization that showed most older men with poor vitamin levels who were assigned a daily multivitamin showed improved blood concentration and overall status of one or more vitamins (but not minerals) by the end of the study. At the start of the study, most of the participants had shortfalls of at least one vitamin (most had shortfalls in three to five), which is where the largest improvements were seen. Multivitamin use also slowed a decline in a specific marker of how well cells use nutrients; this suggests that they might help preserve metabolism and immune health in aging adults.
- Absorption varies from person to person. Researchers are still working toward a better understanding of how well the body uses multivitamins. “They do get absorbed but the amount may vary from person to person,” said Michaels.
Several factors are key:
- “A variety of medications can deplete nutrients,” said D’Adamo. Statins and acid blockers deplete certain nutrients. Aspirin can cause vitamin C to be quickly lost through urine, and other vitamins, like calcium, magnesium, and zinc, can reduce how certain antibiotics are absorbed. (The Linus Pauling Institute provides a comprehensive list of medication/vitamins/minerals interactions on its website.)
- Certain foods may also interfere with absorption. “Some of the really high-fiber foods may impair absorption. Fat-soluble vitamins like vitamin K absorb better when they are taken with fat. And people don’t realize that tea can interfere with the absorption of iron,” said Jampolis.
- The data around the difference between vitamin pills or liquids is less clear. Michels noted that it’s total speculation. “Every supplement company believes that they have the answer and … if they have the data, they’re keeping them to themselves,” he said.
- Multivitamins are mostly safe. None of the experts we spoke with had concerns about the safety of multivitamins, but they all recommended that people read the label for quality and manufacturing certifications. NSF certifies supplements to NSF/ANSI 173, the only American National Standard for testing and certifying dietary supplements for contents and purity. Consumer Lab also provides access to their product testing and reviews. (Full access requires a paid subscription.)
- Middle age may be the best time to start. By the time a person reaches age 50, it might be time to start taking a multivitamin. “We start seeing nutrient deficiencies like the mid-50s and above and there tends to be more and more issues with suboptimal nutrition as they age,” said D’Adamo. Jampolis advises that people start even younger – around age 45.
- They’re not for everyone. Before starting a multivitamin, check in with your doctor, especially if you are on medications or have other health conditions. Multivitamins are not appropriate for everyone, which is why your doctor can provide the best guidance to meet your needs.
Correction: Alexander Michels, PhD, of Oregon State University, was incorrectly referred to as Adam Michaels in a previous version of this story.