The DAS28 findings were especially important, Prof. van Schaardenburg says, adding, “It’s a real change.”
Based on this research, Prof. van Schaardenburg recommends rheumatologists counsel patients with OA about the value of a plant-based diet and show them where they can find more information about it. He also advises querying patients about their diets and stress levels, and encouraging them to shift toward a plant-based diet.
Rheumatologists see patients a few times annually, he notes, giving them more opportunities to sway their patients to change habits. When he advised his patients to try plant-based diets, they often returned to clinic and said, “I feel great.” (Note: Prof. van Schaardenburg retired from clinical practice last year.)
Limitations
The trial results did not surprise Dr. Sammut, she says, because researchers “put a lot of effort into the intervention group” without paying much attention to the control group. This strategy may have affected group differences in both trials, the authors acknowledged.
Dr. Sammut cautioned against drawing any broad conclusions or changing practice habits.
Despite promising results, both Dr. Sammut and Prof. van Schaardenburg noted this research has several other limitations. For one, the sample was not large. Dr. Sammut wondered if lifestyle factors in The Netherlands differ from those in the U.S., leading to lesser effects in the U.S. The U.S. culture, she says, discourages many patients from following a plant-based diet consistently. “I’m not sure [most people on their own] have the time to follow [a plant-based diet],” she says. Many of her patients do not follow the physical therapy regimen she recommends because they are too busy working.
What’s more, ACR guidelines do not include plant-based diets, Dr. Sammut notes. The guidelines do cite weight loss as a goal for OA, and many patients in the studies lost weight, she adds, noting, “The end result—losing weight—is the most important.” But she questions how much of that loss was due to diet vs. other factors. The MSOA trial “does not prove that a plant-based diet is something rheumatologists can recommend. We cannot conclude a plant-based diet is the reason for osteoarthritis patients manifesting improvements in this study,” she says.
The authors acknowledged that, noting that none of the individual impacts of the program’s lifestyle factors could be determined for either trial. “However,” they added in the MSOA paper, “chronic system inflammation is driven by multiple factors including diet, physical activity, and stress. This might explain a decrease in inflammation and an overall improvement of health that is not mediated by weight loss.”
