Use of the supplements, which are used for joint health support, was associated with a 23% reduction in the risk of colorectal cancer, according to data from the Nurses' Health Study and Health Professionals Follow-up Study published in the International Journal of Cancer.
The study, which identifies a correlation and does not show causation, supports data from the VITamins and Lifestyle study (VITAL), published in 2009 (Cancer Epidemiol Biomarker Prev; Vol. 18, pp. 1419–28).
“Results of this study suggest a potential beneficial effect of glucosamine and chondroitin supplementation on risk of colorectal cancer, and further support the previously observed association between use of these supplements and risk of colorectal cancer in the VITAL study,” wrote the researchers.
“Additional study is needed to better understand the association between use of glucosamine and chondroitin and risk of colorectal cancer, and the mechanisms by which these supplements may affect risk of colorectal cancer.”
Glucosamine + chondroitin
Glucosamine & chondroitin sulfate are the big ingredients in the joint health category, with studies such as the $14 million Glucosamine/chondroitin Arthritis Intervention Trial (GAIT), sponsored by the National Institute of Health, reporting that the combination “significantly decreased” knee pain for people suffering from moderate-to-severe osteoarthritis (New England Journal of Medicine, 2006, Vol. 354, pp. 795-808).
However, the market for both ingredients has been in decline in the US. According to Euromonitor International, global retail sales for glucosamine products were $2.041 billion in 2011 while 2015 forecasts pegged the market at $1.770 billion. Chondroitin has suffered from concerns about sourcing leading.
The new study, led by Dr Elizabeth Kantor from the Memorial Sloan Kettering Cancer Center in New York, analyzed data from 68,466 women and 27,934 men participating in the Nurses' Health Study and Health Professionals Follow-up Study, respectively. This yielded 672 cases of colorectal cancer.
After crunching the numbers, the researchers found that any use of glucosamine was associated with a 21% reduction in risk, while any use of chondroitin was associated with a 23% reduction in risk.
While glucosamine in the absence of chondroitin did not show an effect, use of glucosamine + chondroitin was significantly associated with a 23% reduction in risk, wrote Dr Kantor and her co-workers.
The results did not change significantly when the researchers factored in sex, BMI, or physical activity, and the association was comparable when the researchers split the cancers according to colon and rectum.
Commenting on the potential mechanism(s) of action, the researchers noted that glucosamine and chondroitin have been reported to have anti-inflammatory properties, with data from in vitro and animal studies demonstrating reduced inflammation in colonic cells.
“These results, suggesting that glucosamine and chondroitin have biologic effect in the colon, add further plausibility to the observed epidemiologic association between use of glucosamine/chondroitin and risk of [colorectal cancer],” wrote the study authors.
“This laboratory evidence is supported by two human observational studies and a recent small pilot randomized controlled cross-over trial, in which we observed glucosamine/chondroitin to be associated with reduced levels of the systemic inflammatory marker, CRP. Given that inflammation has been strongly implicated in the etiology of [colorectal cancer], this growing body of evidence offers a plausible biologic mechanism by which these supplements may reduce risk of [colorectal cancer].”
Source: International Journal of Cancer
Volume 139, Issue 9, Pages 1949–1957, doi: 10.1002/ijc.30250
“Use of glucosamine and chondroitin supplements in relation to risk of colorectal cancer: Results from the Nurses' Health Study and Health Professionals follow-up study”
Authors: E.D. Kantor et al.