Popular joint supplement glucosamine linked to faster Alzheimer’s progression

[AlphaZance]

A widely used supplement marketed for joint pain relief may be linked to faster progression of Alzheimer's disease, according to new research from the University of Florida.

The study found that people with mild cognitive impairment who reported taking glucosamine were more likely to progress to dementia than those who did not use the supplement. Researchers also uncovered evidence suggesting that glucosamine may interact with biological processes in the brain that are already disrupted in Alzheimer's disease.

The findings, published June 9 in Nature Metabolism, are based on a large analysis of patient health records combined with advanced imaging studies of human brain tissue and mouse models of Alzheimer's disease.

Although the results do not prove that glucosamine causes dementia and will need to be confirmed in clinical trials, researchers say the work adds to growing evidence that metabolic dysfunction plays an important role in neurodegenerative diseases.

"In the United States, there are about 7 million people living with Alzheimer's and millions more with related dementias such as Lewy body or frontotemporal dementia," said senior author Ramon Sun, Ph.D., director of the Center for Advanced Spatial Biomolecule Research and associate director for innovation of UF's McKnight Brain Institute. "A lot of these people actively take an over-the-counter supplement that could be making their disease progression worse."

Glucosamine Use and Dementia Risk

Because glucosamine is widely available and frequently used by older adults to support joint health, the researchers wanted to determine whether it could influence Alzheimer's disease and related dementias (ADRD).

Working with collaborators Yi Guo, Ph.D., and Jiang Bian, Ph.D., the team used artificial intelligence to analyze deidentified UF Health records collected between 2012 and 2024. They focused on patients diagnosed with either ADRD or mild cognitive impairment (MCI).

Among those patients, researchers found that glucosamine use was relatively common. A total of 1,896 patients with ADRD and 2,750 patients with MCI reported taking the supplement, representing about 8% of each group.

After accounting for factors such as age, sex, and demographics, the analysis showed that glucosamine use was associated with a 25% greater likelihood that patients with MCI would later develop dementia.

Researchers also observed that glucosamine use was linked to a 25% increase in mortality risk among people already diagnosed with ADRD. No similar increase was seen among patients with MCI, suggesting that the supplement's effects may differ depending on the stage of disease.

A Potentially Important Metabolic Pathway

The study also pointed to a specific biological process that may help explain the association.

Researchers identified evidence that a protein and sugar-tagging pathway is excessively active in Alzheimer's disease. According to the team, this pathway could represent a new target for future treatments.

"Our results suggest that altered metabolism is a significant contributor to Alzheimer's progression and, in addition, addressing the metabolic defect could be an important complement to approaches focused on Alzheimer's plaques and tangles," Sun said.

The discovery was made possible by advanced spatial analysis technology developed in Sun's laboratory.

"This technology allows us to examine thousands and thousands of molecules created when the body breaks down food or drugs and to uncover intricate pathways that otherwise would stay hidden," Sun said.

How Glucosamine Affects the Brain

To investigate further, researchers focused on glucosamine because it is a naturally occurring sugar-related molecule that can cross the blood-brain barrier. Once in the brain, it can contribute to biochemical pathways involved in building complex sugar structures on proteins. Commercial glucosamine supplements are often produced from materials such as shellfish shells or corn.

The findings suggest that glucosamine's effects may depend heavily on the biological environment in which it is acting.

"The electronic health record data are very provocative," said Matt Gentry, Ph.D., chair of UF's Department of Biochemistry and Molecular Biology and a study co-author. "While it's an association and not proof of causality, it does raise an important clinical question that now deserves much more attention."

According to Gentry, the Alzheimer's brain may be especially susceptible to disruptions in this pathway compared with healthy brain tissue.

Mouse Studies and Human Brain Tissue Findings

Experiments in genetically modified mice provided additional support for the hypothesis.

Researchers found that glucosamine significantly increased the attachment of sugar molecules to proteins within cells. Mice receiving glucosamine also showed worsening deficits in social memory, which is the ability to recognize and remember other individuals.

When scientists chemically reduced this sugar-tagging activity, memory performance improved.

The team then examined human brain tissue from the UF Neuromedicine Brain and Tissue Bank in collaboration with Stefan Prokop, M.D. Compared with healthy control samples, Alzheimer's brain specimens showed substantially higher levels of sugar attachment to proteins.

Taken together, the researchers say these findings suggest that this metabolic abnormality may actively contribute to Alzheimer's disease rather than simply occur as a consequence of it.

"Proteins are the cell's molecular machines, and many of them need sugar tags added in just the right way to fold correctly, travel to the right place and do their jobs," Gentry said. "What we found in Alzheimer's is that this sugar-tagging system appears to be overactive. The Alzheimer's brain is adding too many of these sugar structures, and this seems to contribute to the disease rather than protect against it."
https://www.sciencedaily.com/releases/2026/06/260610003044.htm

[CrumblingCookie]

@AlphaZance
May well vastly overlap with what is already known about increased brain fungal loads in neurodegenerative diseases and what had been shared on glucosamine by late Travis:

Why, it's common knowledge that starch is always feeding Candida - and is even somewhat well-known that Candida grows best on potato agar. Specifically, glucosamine induces the yeast➝hyphal transition because it is the monosaccharide which constitutes chitin - a polysaccharide. Candida species can make their own glucosamine enzymatically, using the two substrates glucose and glutamine under the direction of glucosamine-6-phosphate synthase.
Straight glucosamine powerfully induces the yeast➝hyphal transition
Candida albicans is commensal; it's everywhere; the only thing to prevent is the yeast➝hyphal transition most powerfully induced by prostaglandin E₂, glucosamine, or both of the latter's precursors in high concentrations.
Now add linoleic acid to this—the prostaglandin E₂ precursor—and you then have a powerful yeast➝hyphal transducer—more commonly known as potato chips, bread, and granola bars.

[LucH]

Talk with AI (Claude) to try to understand Crumblecooking’s comment.

• Some info to move the Schmilblick forward (to move things along).

Context:
Weak ground: researchers focused on patients diagnosed with either ADRD or mild cognitive impairment (MCI).
A widely used supplement marketed for joint pain relief may be linked to faster progression of Alzheimer's disease, according to new research from the University of Florida.
Researchers found that glucosamine significantly increased the attachment of sugar molecules to proteins within cells. Mice receiving glucosamine also showed worsening deficits in social memory, which is the ability to recognize and remember other individuals.
When scientists chemically reduced this sugar-tagging activity, memory performance improved.
"In the United States, there are about 7 million people living with Alzheimer's and millions more with related dementias such as Lewy body or frontotemporal dementia," said senior author Ramon Sun, Ph.D., director of the Center for Advanced Spatial Biomolecule Research and associate director for innovation of UF's McKnight Brain Institute. "A lot of these people actively take an over-the-counter supplement that could be making their disease progression worse."

Comment from the forumer Crumblecooking:
Add linoleic acid to this—the prostaglandin E₂ precursor—and you then have a powerful yeast➝hyphal transducer—more commonly known as potato chips, bread, and granola bars.

Comment from LucH (me) (not yet posted):
I know we have here a weak ground: already inflamed cells behind BBB by ROS perturb the cohesion, weakening the balance behind BBB: There is inflammation (via ROS) and perturbation in the brain cells as far as the homeostatic balance is concerned:

Detailed explanation:
The blood-brain barrier (BBB) is composed primarily of cerebral microvascular endothelial cells and astrocytes linked by tight junctions (TJs) and adhesion molecules (AMs). This system maintains the homeostatic balance between the brain parenchyma and the extracellular fluid.
=> Not a proof, OK. But more and more studies take this direction...
How to Help a Leaky BBB before it’s too late (usual process for ¾ people above 80ies)

a) Which useful molecules can cross the BBB:

• Aspirin (mind the platelet impact)
• Caffeine (coffee and tea)
• EGCG (green tea)
• Resveratrol
• Taurine
• Vitamin E
• Vitamin C
• Etc.
  See detailed information on reference 2.

b) How to Heal a Leaky Blood-Brain Barrier
Which Supplements Repair the Blood-Brain Barrier?
Several B vitamins support blood-brain barrier health: a vitamin B1 (thiamine) deficiency disrupts the blood-brain barrier, and supplementation can restore it. Vitamins B12, B5, and B9 (folate) can restore the integrity of the blood-brain barrier. (4) Magnesium, as a cofactor in over 300 biochemical processes, affects brain neurotransmitters, enzymes, and hormones. Magnesium L-threonate is often used for its potential brain benefits and may help manage certain brain disorders, such as depression, Alzheimer's disease, and age-related memory loss.
To be continued on the reference 1.

Sources and references

1. Useful link: Alzheimer's Cognitive Decline and Inflammation (In French but with links in English)
   https://mirzoune-ciboulette.forumactif.org/t2067-declin-cognitif-dans-alzheimer-et-inflammation#29882
2. What can get through the BBB?
   https://my.clevelandclinic.org/health/body/24931-blood-brain-barrier-bbb
   The list of what can make it through your BBB is extremely lengthy, so here are some examples …
3. Antocyanins can cross the BBB
   Phenolic compounds that cross the blood–brain barrier exert positive health effects as central nervous system antioxidants. 2021 Food & Function. Dafne Velásquez-Jiménez et al.
4. What supplements repair the blood-brain barrier?
   https://thefnc.com/research/nutrients-to-help-repair-your-blood-brain-barrier/#:~:text=B vitamins.,restore blood-brain barrier integrity
5. Glutamine et cancer
   Un lien intéressant :
   https://www.julienvenesson.fr/glutamine-cancer/
   A natural compound, EGCG from green tea, also shows promise. It counteracts the action of glutamate dehydrogenase, which converts glutamate into α-ketoglutarate, leading to the death of cancer cells.
   https://www.julienvenesson.fr/la-quercetine-ameliore-les-effets-du-the-vert-sur-la-sante/
   Glutamine is the preferred amino acid of cancer cells, required for their growth. But if you try to limit this intake, the cancer will destroy muscle tissue to obtain it. You can try to ration it, but never eliminate it. Therefore, you limit it, you don't eliminate it.
   NB: Whenever I suffer from a weak / a thin layer of stomach mucin, I associate ¼ tsp glutamine and ¼ tsp taurine powder (+ 1.5 g magnesium bisglycinate). Take one hour before bedtime. Always associate both to dampen the possible glutamate pathway.

Question for AI (Claude)
I don’t want a comment or an analyze of my answer but I’d like an explanation for Crumblecooking’s comment:
“Add linoleic acid to this—the prostaglandin E₂ precursor—and you then have a powerful yeast➝hyphal transducer—more commonly known as potato chips, bread, and granola bars.”
=> What is the mechanism? Asparagine becoming nitrosamine?

Short answer for IA (summarized because in French and 2 pages A4 long)
No, not linked to nitrosamine.
Vocabulary: the yeast→hyphal morphological transition.
Hyphal: Adjective derived from “hypha”, describing anything related to this filamentous form.
We have a morphological change from the yeast form (isolated round cell) to the invasive filamentous form.
So, ultra-processed foods rich in omega-6 oils potentiate the pro-Alzheimer's effect of glucosamine via a dual mechanism: local inflammation (PGE₂) + fungal dysbiosis, promoting a compromised intestinal mucosa/BBB. The hyphal transition of Candida increases epithelial permeability, exacerbating precisely the leaky BBB problem you describe (LucH talking with Claude).

LucH said:
Okay, I get it. It's a stimulant on already fragile ground.

IA says:
Exactly.
That's the most accurate wording.
A stimulator—not a primary cause—on an already weakened foundation:
• Compromised BBB
• Chronic low-grade inflammation
• Already disrupted O-GlcNAcylation
Glucosamine + PGE₂ don't initiate the disease; they accelerate what's already underway. That's why the study refers to aggravated progression, not a trigger.
This ties in with your notion of a weak ground from the introduction—the underlying condition precedes it, the stimulator amplifies it.