Common supplement may accelerate memory loss from Alzheimer’s disease

People with Alzheimer’s disease who took the supplement glucosamine were 25% more likely to die within five years, according to a study published in the journal Nature Metabolism. Researchers from the University of Florida also found that individuals with mild cognitive impairment who used the supplement were 25% more likely to progress to full Alzheimer’s.

Glucosamine is an amino sugar composed of glucose and glutamine. It is sold over the counter as a remedy for arthritis and joint pain, with more than 40 million Americans taking it annually.

The Food and Drug Administration classifies glucosamine as a dietary supplement rather than a prescription drug. This allows consumers to purchase it without a doctor’s oversight.

How does glucosamine affect the brain?

Researchers at the University of Florida analyzed anonymized medical records from the University of Florida Health system. The data included 24,000 patients with dementia and 41,000 people with mild cognitive impairment.

The team identified a condition called hyperglycosylation. In people with Alzheimer’s, sugar chains called N-glycans pile up on brain cells and proteins where they do not belong. This buildup causes proteins to fail, which leads to cell death and memory loss.

Experiments on mice engineered with Alzheimer’s-like symptoms supported these findings. Feeding these mice glucosamine made their memory loss worse. Conversely, blocking the enzyme that creates sugars like glucosamine improved dementia symptoms in the mice. Healthy mice showed no effect from the supplement.

Is glucosamine safe for everyone?

The University of Florida researchers stated that their findings qualify, but do not contradict, previous reports. Earlier studies linked glucosamine to a lower dementia risk in adults with healthy brains.

The current data suggests the supplement may be safe or even protective for a healthy brain. However, it may be harmful for brains already experiencing cognitive decline.

What happens next in the research?

Because the study relied on patient records, researchers cannot yet prove that glucosamine causes faster decline, only that an association exists. A controlled experiment would be required to prove causation, but researchers noted that administering the supplement to high-risk patients would be unethical.

A possible next step involves a clinical trial following the 8% of dementia patients in the database who took glucosamine and then stopped. Researchers hope to see if discontinuing the supplement slows cognitive decline.

The team may also screen compounds that block N-glycan molecules to see if reducing sugar buildup can slow or reverse Alzheimer’s. Additionally, they plan to explore whether other supplements processed similarly to glucosamine carry similar risks.

Frequently Asked Questions

What is glucosamine?
Glucosamine is an amino sugar made of glucose and glutamine. It is commonly used as an over-the-counter supplement for joint pain and arthritis.

Who was included in the University of Florida study?
The analysis used anonymized records from 24,000 patients with dementia and 41,000 patients with mild cognitive impairment.

Does this mean glucosamine causes Alzheimer’s?
The study shows an association between glucosamine use and increased risk of death or progression to Alzheimer’s in those already impaired, but it does not prove causation.

Do you check with a healthcare provider before starting new over-the-counter supplements?