Glucosamine May Contribute to Alzheimer’s Disease

By Pat Anson

An over-the-counter supplement used by millions of people around the world to relieve joint pain has been associated with Alzheimer’s disease and other advanced forms of dementia, according to a new study.

Neuroscientists at the University of Florida say glucosamine raises the risk of someone progressing from mild cognitive impairment to Alzheimer’s disease by about 25 percent.

Glucosamine is an amino sugar found in shellfish that helps build cartilage, ligaments, tendons, and synovial fluid in joints. It is used annually by about 40 million Americans, many of them elderly, to reduce inflammation and symptoms of osteoarthritis.

What many seniors don’t realize is that glucosamine may also be accelerating the formation of protein plaques in their brain, which have been linked to dementia. 

“A lot of these people actively take an over-the-counter supplement that could be making their disease progression worse,” senior author Ramon Sun, PhD, a biochemist and molecular biologist, said in a press release.

It’s important to note that the study findings, published in the journal Nature Metabolism, are preliminary and don’t establish a cause and effect relationship between glucosamine and Alzheimer’s – only an association.

The findings are based on a large retrospective analysis of health records for over 50,000 patients diagnosed with Alzheimer’s disease-related dementias (ADRDs) or mild cognitive impairment (MCI). While most patients with MCI remained stable or even recovered cognitive ability, about 5% progressed to ADRD, representing a clinical worsening of cognitive decline. 

About 8% of the patients studied reported taking glucosamine supplements. When compared to patients who didn’t take glucosamine, researchers saw a 25% higher risk of patients with MCI transitioning to ADRD in the glucosamine user group. In addition, glucosamine use was associated with a 25% increase in mortality risk among ADRD patients.

Researchers believe glucosamine crosses the blood-brain barrier and feeds into pathways that build sugar residue on protein cells. Patients with Alzheimer’s appear to be more vulnerable to this metabolic activity than those with healthy brains.

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

In tests on genetically modified mice, the UF research team found that glucosamine significantly increased sugar residue on proteins in the brain and reduced the social recognition behavior of mice. When researchers chemically suppressed this process, their “social memory” improved.

Advanced imaging studies on human Alzheimer’s brains also showed significantly increased sugar attachment to proteins compared to healthy brains. 

Taken together, the findings suggest that metabolic dysfunction is not simply a secondary aspect of Alzheimer’s pathology, but a contributing cause. 

“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.”

The good news about this research is that it could lead to new ways to prevent Alzheimer’s or slow its development.

“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.    

Glucosamine is the fourth most widely used supplement in the United States. It is also widely used in China and Europe. Glucosamine is often combined with chondroitin to help build or restore joint cartilage. 

While further studies are needed, the Mayo Clinic says glucosamine “might provide some pain relief” for people with knee osteoarthritis. 

The Hidden Benefits of Glucosamine

By Pat Anson, PNN Editor

Do you take glucosamine supplements to reduce joint pain and stiffness? You’re not alone if you do. According to a 2007 survey, nearly 20 percent of U.S. adults take glucosamine to prevent or treat pain from osteoarthritis, back pain and other conditions.

The evidence to support the use of glucosamine for joint pain is thin, but a large new study in The BMJ suggests regular use of the supplement can reduce the risk of cardiovascular disease.

Researchers at Tulane University analyzed 7 years of extensive health data for almost half a million adults aged 40 to 69 enrolled in the UK Biobank study. Those who regularly took glucosamine were about 15% less likely to develop heart disease or have a stroke.

Glucosamine occurs naturally in the fluid around joints and plays an importantly role in building cartilage. Glucosamine is extracted from shellfish and is often combined in supplements with chondroitin, a similar substance that is also found in joints.

People who took glucosamine in the BMJ study were more likely to be women, older, more physically active, have healthier diets and take other supplements.

Over the course of seven years, 2.2% of those who did not use glucosamine had a heart attack or stroke, compared to 2.0% of people who did use glucosamine. People who used glucosamine were also less likely to die from a heart attack or stroke, 0.5% vs. 0.7% of those who didn’t use the supplement.

The difference doesn’t appear to be significant, but when adjusted for risk and other factors, it means that glucosamine users had a 22% lower risk of dying from a heart attack or stroke.

For smokers, the benefits of regular glucosamine use were even greater. They had 37% less risk of having coronary heart disease compared to smokers who didn’t use the supplements.

Researchers didn’t establish the reason why glucosamine lowers the risk of cardiovascular disease (CVD), but they believe the supplements help reduce inflammation – one of the main factors involved in the development of heart disease, as well as chronic pain.

“Several potential mechanisms could explain the observed protective relation between glucosamine use and CVD diseases. In the National Health and Nutrition Examination Survey (NHANES) study, regular use of glucosamine was associated with a statistically significant reduction in C reactive protein concentrations, which is a marker for systemic inflammation,” researchers reported. “Other mechanisms might also be involved, and future investigations are needed to explore the functional roles of glucosamine in cardiovascular health.”

The UK’s National Health Service (NHS) downplayed the study findings, pointing out the cardiovascular benefits of glucosamine are “quite small.”

“If you want to reduce your risk of having a heart attack or stroke, it would be much better to concentrate on living a healthy lifestyle, rather than paying for glucosamine supplements,” the NHS said.

Supplements Help Relieve Pain of Osteoarthritis

By Pat Anson, Editor

Two natural dietary supplements are effective at relieving pain and stiffness caused by osteoarthritis, without the side effects caused by non-steroidal anti-inflammatory drugs (NSAIDs), according to two new research studies.

One study found that a combination of glucosamine and chondroitin was effective in treating knee osteoarthritis (OA), while the other study examined an herbal treatment used for thousands of years in Chinese medicine to treat joint pain.

Osteoarthritis is a progressive joint disorder caused by painful inflammation of soft tissue, which leads to thinning of cartilage and joint damage in the knees, hips, fingers and spine.

The first study was a meta-analysis (a study of studies) involving over 16,000 patients with knee OA. Published in the journal Scientific Reports, it is the first study of its kind to compare glucosamine, chondroitin, and the two in combination, against the NSAID celecoxib or a placebo in the treatment of knee OA.

Researchers found that the combination of glucosamine and chondroitin was associated with significant improvement in pain relief and functional enhancement, compared to placebo, without the high rate of gastrointestinal side effects in patients who received celecoxib.

There was "no significant difference" in pain relief between celecoxib and the glucosamine/chondroitin combination.

"This comprehensive analysis provides us with a wealth of historical data supporting the safety and efficacy of glucosamine and chondroitin in the management of joint health. It is consistent with recent findings suggesting that the efficacy of this combination is comparable to celecoxib in terms of relieving pain and improving function," said lead author Chao Zeng, MD, of the Department of Orthopaedics at Xiangya Hospital at Central South University in Changsha, China.

"This is important news for patients requiring long-term treatment, as the potential side-effect associated with profiles of NSAIDs such as celecoxib warrant consideration of alternative treatment options that are safe and effective."

Glucosamine and chondroitin are both found in healthy cartilage, which acts as a cushion between the bones in a joint. In dietary supplements, glucosamine can be harvested from shells and shellfish or made synthetically. Chondroitin can also be made in a lab, or manufactured from cartilage found in cows, pigs, sharks and other animals.

Chondroitin and glucosamine are popular in supplements used to treat joint pain, but according to the Arthritis Foundation, “most studies assessing their effectiveness show modest to no improvement compared with placebo in either pain relief or joint damage.” The American Academy of Orthopaedic Surgeons also recommends against their use.

The second, smaller study examined the effectiveness of Arthrem, a dietary supplement made in New Zealand that contains an herbal extract from the plant Artemisia annua (Qinghaosu), which has been used in Chinese medicine for more than 2,000 years.

Forty-two people with osteoarthritis of the knee or hip were enrolled in the randomized, controlled study, which was published in the journal Clinical Rheumatology. Researchers say patients who took an Arthrem capsule twice a day for 12 weeks had a significant reduction in pain and stiffness and an increase in their physical function.

"The published results show that the natural product, Arthrem, has potential as an anti-inflammatory/analgesic in osteoarthritis," said Dr. Sheena Hunt, study co-author and principal scientist for Promisia Integrative, the company that makes Arthrem and conducted the study.

"Particularly positive results were observed in a subset of patients with mild to moderate osteoarthritis. In this subgroup, the average magnitude of pain after 12 weeks of taking Arthrem was less than half of the value at the start of the study. Arthrem at this dose was also well tolerated with no treatment-related side effects."

Arthrem recently became available in the United States. Those who qualify can sign up for a free, no obligation, two month trial online at www.Arthrem.com.

Compared to pharmaceuticals, the U.S. Food and Drug Administration loosely regulates the $35 billion dietary supplement industry and many manufacturers' claims about their products are unverified.  The agency recently announced plans to tighten enforcement of the industry by creating a dietary supplement office.

The World Health Organization estimates that about 10% of men and 18% of women over age 60 have osteoarthritis.