Multivitamin Use Improves Nutritional Status in Older Men
Multivitamins are often recommended to help older adults fill nutritional gaps and improve their vitamin and mineral status, but do they work as intended? The results of a new clinical trial from Dr. Tory Hagen and colleagues at the Linus Pauling Institute show that older men do benefit from taking a daily multivitamin, with gains that go beyond meeting nutritional needs.
A balanced diet is essential to health for many reasons. For one, it provides the vitamins and minerals that are needed for proper bodily function. However, many people do not meet their vitamin and mineral needs.
Older adults are at greater risk for deficiencies in certain vitamins and minerals. One possible reason is that as we age, we tend to eat less food, leading to lower micronutrient intake. Other factors contribute to poor micronutrient status in older adults, such as changes in dietary habits, food preferences, decreased nutrient absorption, gastrointestinal problems, inflammation, and the influence of certain medications.
“All of this creates a strong case for multivitamins on top of a balanced diet,” says Dr. Tory Hagen, one of the principal investigators focused on healthy aging at the Linus Pauling Institute. This is one reason the Institute recommends that all adults, especially older adults, take a daily multivitamin supplement that contains 100% of the daily value (DV) for most vitamins and minerals.
However, only a few studies have examined how multivitamin use improves vitamin and mineral status in older adults. Ideally, this status would be assessed by an objective measure of the effect of multivitamins on the body, such as a blood or cellular biomarker. For multivitamins to be deemed effective, they would need to improve micronutrient status over time.
To tackle the question of the effectiveness of multivitamins in older adults, Dr. Hagen assembled a team of Linus Pauling Institute researchers to conduct a randomized controlled trial in men 67 years of age and above. The study was recently published in the journal Nutrients.
Room for improvement
To enroll in the study, men had to be generally healthy for their age, although some were taking prescription medications to treat chronic health conditions. Many used supplements regularly; participants needed to cease the use of any supplements containing vitamins and minerals prior to and during the trial. An exception was made for vitamin D because it is often recommended by physicians.
At the beginning of the study, each participant gave blood samples to assess their baseline vitamin status. For each vitamin measured, the researchers used literature reports to classify participants as “optimal” (i.e., blood vitamin levels that were considered ideal) or “suboptimal” (i.e., lower than “optimal”; for more detail, see below).
“Overall, we certainly found room for improvement,” Hagen points out. The blood tests revealed that almost all of the participants started the study with “suboptimal” vitamin concentrations. More than half of the participants were falling short in three or more vitamins.
In particular, vitamin B12, vitamin C, and vitamin D were at less-than-ideal levels for this group of older men. Vitamin E and vitamin K concentrations were also low in some individuals.
Although several minerals were measured in the blood samples, the analysis did not reveal anything notable. This was not surprising because mineral levels in the blood stay relatively steady and are generally not considered good biomarkers of adequacy except in the case of severe deficiency. No severe mineral deficiencies were detected in these participants.
The impact of multivitamins
To test the effects of supplementation, half of the 35 men participating in this study took Centrum Silver Men (a daily multivitamin supplement containing vitamins, minerals, and other dietary factors) for approximately eight months. The other half took an identical placebo pill. Neither group knew what they were taking, nor did the investigators.
At the end of the study, participants in the multivitamin group had statistically significant increases in blood concentrations of several vitamins compared to the placebo group. This was notable for vitamin B6, vitamin D, and vitamin E, as well as β-carotene, a carotenoid compound that contributes to vitamin A status.
Centrum Silver formulas are specifically formulated for older adults and differ in nutrient content for men and women. The researchers chose to initially focus on men.
What is “Optimal” Vitamin Status?
One of the challenges for this trial, and for precision nutrition in general, is defining “optimal” status. Many researchers around the globe neither agree on an appropriate biomarker for status, such as blood vitamin concentration, nor what these biomarkers may indicate for health.
“Suboptimal” vitamin status is slightly easier to define. This may range from overt deficiency with noticeable negative health outcomes to more subtle effects like increased risk for disease over a lifetime.
For this study, the research team relied on literature reports that related the blood concentrations of a given vitamin to an increased risk for disease or death. Concentrations above this amount were considered “optimal” status.
For some vitamins, the response to the multivitamin supplement was mixed. No improvement was noted in men who began the study with higher-than-average blood concentrations of folate, vitamin B12, vitamin C, and vitamin K, which was not surprising. Yet, a dramatic improvement was observed in those participants who started off with the lowest baseline levels.
Ultimately, participants taking the multivitamin improved their vitamin status. Many participants in this group moved from “suboptimal” vitamin status to blood levels that were considered optimal.
By contrast, the blood vitamin status of many participants in the placebo group declined. In fact, several participants who had “optimal” vitamin status at the start of the trial fell into “suboptimal” status after taking a placebo for eight months.
To connect these findings to a measurable impact on bodily function, Hagen analyzed oxygen consumption in the participants’ white blood cells. This is because many vitamins are used by the body’s cells to produce the energy that maintains metabolism, and cells consume oxygen in that process.
Interestingly, in the placebo group, a noticeable decrease in cellular oxygen consumption was observed between the beginning and the end of the study. By contrast, cellular oxygen consumption was sustained in participants supplemented with multivitamins — and the difference between groups was significant.
Hagen believes that these data reinforce the connections between micronutrients and metabolism.
“We know that multiple nutrients present in the multivitamin supplement are important to the mitochondria and will help sustain metabolic function in older adults,” he explained. “Now we would like to know which are the most important. It might help explain why oxygen consumption dropped so dramatically in the placebo group.”
The bottom line
Results of this study show that taking a daily multivitamin has notable nutritional benefits for healthy older men. In some cases, a multivitamin can improve blood vitamin levels, and in other cases, it can prevent the declines associated with a less-than-perfect diet.
The findings also indicate that multivitamins could influence metabolic health in older adults. This could be one way that multivitamin use influences the risk for chronic disease.
Future studies in older women will determine if these results are influenced by sex.
Additionally, it would be helpful to study the effects of multivitamins in younger adults, to determine the dependency on life stage.
References:
Michels et al. Nutrients 15 (2023); doi: 10.3390/nu15122691
Wallace et al. J Nutr Gerontol Geriatr 38 (2019); doi: 10.1080/21551197.2019.1656135
Blumberg et al. Nutrients 9 (2017); doi: 10.3390/nu9080849
