Community Update (10/1/26)

Wellness

Supplements and the Aging Brain

by Joan M. Smith

I recently had a giant Ahha! after reading a newspaper article, then seeing the disconnect in action between knowledge and behavior. I will relate those two things later, but first I will discuss the article by Ariana Eunjung Cha in the Sept. 15, 2026, Washington Post. Cha raises the concern about using supplements, usually over the counter (OTC), by older people. We often think those “natural” supplements are equivalent to healthy food, and indeed some can be beneficial. But our brains change as we age, and we process supplements differently from younger people. Things we eat/swallow are absorbed differently, and they interact with other intake, such as food or medications, differently.

In January of this year, researchers reported an association between vitamin D supplement use and faster cognitive decline among older adults who already had normal vitamin D blood levels. In April, another study found a link between older adults taking omega-3 supplements and greater cognitive deterioration over time. And, in June, researchers found that older adults taking glucosamine (used for joint pain) showed a much higher likelihood of progressing from mild cognitive impairment to dementia over five years than their peers not taking it.

These results stunned many researchers and requires further research, of course. But we have all had so much information hyping these supplements that it spins heads trying to make sense of it all. But this is very recent research, and we need to pay attention, just as do researchers who are finally beginning to take seriously that aging changes how the brain handles fats, calcium and glucose, and how it responds to inflammation, which could alter how nutrients and drugs reach brain tissue in the first place.

What to do? First, do not empty your medicine cabinet, but have an in-depth conversation with your healthcare provider about each supplement and how it affects aging brains. While these supplements may be good for some people, but for whom and at what age, and how exactly do they interact with your prescription medications? Some differences include that a younger brain is more plastic, clears waste more efficiently, regulates inflammation better and has greater capacity to recover from cellular stress.  An older brain, while able to function well, has less biological reserve to compensate when something interferes with normal functioning. So, let’s look at the supplements I mentioned.

Vitamin D is linked with cognitive function; too low a circulating level plus low dietary vitamin D intake is linked with accelerated cognitive decline. Thus, your circulating vitamin D level needs to be checked regularly. Older people are more prone to a lower level, thus your provider may prescribe the supplement; this brings it to a normal level.  The problem resides when your level is normal, but you take a supplement anyway; this overly high level is associated with cognitive decline.

Fish oil and omega-3 had been thought to be useful for cognitive benefits. However, study after study failed to show this result. And, a new analysis in the Journal of Prevention of Alzheimer’s Disease showed opposite results. That study used health information of adults ages 55-90 with a range of cognitive health. They compared omega-3 users with non-users over five years and found that the supplement users experienced faster cognitive decline.

Glucosamine has been a very popular supplement mostly used by middle-aged and older adults to reduce joint pain due to osteoarthritis. Since glucosamine is a building block for molecules found in cartilage and joint tissue, it would seem obvious that this would help. There is mixed evidence of the efficacy regarding joint pain. Subsequently, researchers found that glucosamine users had roughly 25 percent greater likelihood of progressing from mild cognitive impairment to Alzheimer’s disease or a related dementia. And, among patients who had Alzheimer’s or dementia, glucosamine use was associated with about a 25 percent higher rate of death.

Whew. Take a breath. It is important to know that none of these findings are conclusive on their own. So the researchers do not suggest that older adults stop taking any of these supplements. But this is where that conversation with your healthcare provider takes place!

My Ahha! occurred during a visit to an old friend, who I thought was pretty savvy about medication and OTC drug use. I was floored to find she was a symptom-fixer; every time she had a symptom, she would seek out OTC fixers for it. But, this was not taking into consideration her already large number of prescribed medications. And she assumed meds were interchangeable. (NOTE: statins are not interchangeable!) Also, adding OTC meds to prescribed meds can have a cumulative effect. Mixing medications and OTC meds and supplements can have disastrous interactions. This is also when you have the conversation with your provider, and report ALL the meds you take, including OTC and supplements, which often get overlooked by us as medications.  My story has a positive outcome: she now has an appointment with her provider and promised to take all of the separate labeled bags of all of the above to her doctor.