By Maria Cohut

Fact checked by Isabel Godfrey

Glucosamine, a dietary supplement that people commonly take to ease joint pain and reduce symptoms of osteoarthritis, may lower the risk of cardiovascular problems, according to a study analyzing health data from over 400,000 participants.

Information from the National Center for Complementary and Integrative Health shows that about 2.6% of adults in the United States — which equates to 6.5 million people — take glucosamine, chondroitin, or both. These two dietary supplements treat joint painand strengthen cartilage, respectively.

This statistic makes glucosamine one of the most popular supplements among the U.S. adult population.

Now, researchers from Tulane University in New Orleans, LA, have carried out a large observational study and found that people who take glucosamine may also have a lower risk of cardiovascular disease and adverse health events relating to the heart or the vascular system, such as stroke.

The research team, which Prof. Lu Qi from Tulane led, accessed the U.K. Biobank study database to use available data from 466,039 participants. None of these participants had cardiovascular disease at baseline, and they all submitted information on their use of dietary supplements.

Among these participants, 19.3% — or about one in five — said that they took glucosamine when they joined the study.

The study’s findings, which appear in the BMJ, suggest that taking glucosamine on a regular basis may help prevent cardiovascular problems. However, the current study is observational, and the authors warn that further trials should test whether there is a causal relationship behind this association.

Does glucosamine prevent heartproblems?

Prof. Qi and team looked at the participants’ hospital records and, when necessary, their death records over an average follow-up period of 7 years. They noted whether each participant developed cardiovascular disease, experienced any cardiovascular problems — including coronary heart disease and stroke — or died due to cardiovascular disease.

The researchers found that people who had reported using this supplement had a 15% lower risk of experiencing a cardiovascular disease-related event compared with participants who did not take glucosamine. They also had a 9–22% lower risk of developing coronary heart disease, experiencing a stroke, and dying from cardiovascular-related causes.

These associations were independent of modifying factors, such as a person’s age, biological sex, body mass index (BMI), lifestyle and diet, and medication and supplement use, for which the researchers accounted.

At the same time, Prof. Qi and colleagues also noted that these associations were stronger in current smokers, who saw a 37% lower risk of heart disease with glucosamine supplementation, than in former smokers and never-smokers, whose risk was 18% and 12% lower respectively.

The researchers hypothesize that if there is a causal explanation, it may lie in certain biological mechanisms that relate to inflammation. For instance, they note that there is an association between glucosamine use and lower levels of C-reactive protein in the body.

Researchers have linked this protein to heightened inflammation. Therefore, glucosamine may actually help reduce that inflammation, which is present at higher levels in smokers than in never-smokers and former smokers.

Another hypothesis is that taking glucosamine may have similar effects to following a diet low in carbohydrates, which studies have also tied to a lower risk of cardiovascular disease.

The study authors conclude their paper by saying:

However, they also caution that, due to the observational nature of this study, “[f]urther clinical trials are needed to test this hypothesis.”