New research from the UK suggests that sulforaphane, a compound found in broccoli and other cruciferous vegetables such as cabbage and Brussels sprouts, could help fight osteoarthritis, the most common form of arthritis.
Led by the University of East Anglia (UEA), the study used cell and tissue tests to show that sulforaphane blocked cartilage-destroying enzymes by intercepting a molecule that causes inflammation.
The researchers also found that mice fed a sulforaphane-rich diet suffered significantly less cartilage damage and osteoarthritis compared with mice whose diet did not contain the compound. Their research is published in the journal Arthritis & Rheumatism.
Sulforaphane is released when eating cruciferous vegetables such as:
- Brussels sprouts
- Bok choy or Chinese cabbage.
Previous studies have already suggested that the compound has anti-cancer and anti-inflammatory properties.
First major study to show sulforaphane may influence joint health
But this new study is the first to show in a major way how the compound influences joint health. The team wanted to find out if sulforaphane got into joints in sufficient quantities to have an effect.
Lead researcher Ian Clark, professor of musculoskeletal biology at UEA, says:
"The results from this study are very promising. We have shown that this works in the three laboratory models we have tried, in cartilage cells, tissue and mice."
Prof. Clark says they now want to show it works in humans, "It would be very powerful if we could," he adds.
Patients will be eating "super broccoli" with high amounts of sulforaphane so researchers can show how the compound helps joints.
The team is planning a small trial in 40 osteoarthritis patients due to have joint replacement surgery.
They hope the results of that will lead to funding for a larger trial of the effects of eating broccoli on osteoarthritis, joint function and pain itself.
In the small trial, for two weeks before their surgery, half of the patients will be eating a "super broccoli" that was specially bred to contain high amounts of sulforaphane.
After surgery, the team will compare the patients who ate the super broccoli with those who did not, to look at whether the compound can be detected in the replaced joints and whether it altered joint metabolism.
Osteoarthritis - a major cause of disability
Osteoarthritis is a painful and often limiting joint disease affecting the hands, feet, spine, hips and knees in particular.
According to the US Centers for Disease Control and Prevention (CDC), the condition affects 27 million American adults. In the UK, figures from Arthritis Research UK, who helped fund this new study, suggest more than 8.5 million people have the disease.
Age and obesity are the most common contributors to osteoarthritis. There is currently no cure, other than pain relief - which often does not work, or joint replacement.
Prof. Clark says: "Osteoarthritis is a major cause of disability. It is a huge health burden, but a huge financial burden too, which will get worse in an increasingly aging and obese population such as ours."
"Developing new strategies for combating age-related diseases such as osteoarthritis is vital, both to improve the quality of life for sufferers and to reduce the economic burden on society."
Although surgery is successful, he says, it is not the answer. Once you have the condition, it is important to slow its progress, and progression to surgery. Plus, he explains that prevention is preferable, and changes to lifestyle and diet may be the only way to achieve it:
"As well as treating those who already have the condition, you need to be able to tell healthy people how to protect their joints into the future.
There is currently no way in to the disease pharmaceutically and you cannot give healthy people drugs unnecessarily, so this is where diet could be a safe alternative."
Could other dietary compounds protect joints?
Studies like these help establish whether changes to diet might work. Prof. Clark says once you know that, you can can start looking for other dietary compounds with similar effects, and then be in position to advise people what to eat to protect their joints.
Professor Alan Silman, medical director for Arthritis Research UK, says:
"Until now research has failed to show that food or diet can play any part in reducing the progression of osteoarthritis, so if these findings can be replicated in humans, it would be quite a breakthrough."
As well as Arthritis Research UK, other bodies helped finance the study - the Biotechnology and Biological Sciences Research Council's (BBSRC) Diet and Health Research Industry Club (DRINC, who are also sponsoring the small trial in patients) and The Dunhill Medical Trust.