A randomized, controlled study finds that a diet low in carbs can relieve pain for people who have knee osteoarthritis. Osteoarthritis is the most widespread form of arthritis among older adults in the United States. Knee osteoarthritis, in particular, affects about 10% of men and 13% of women ages 60 and above. According to some estimates, the condition affects 40% of people over the age of 70. There is currently no cure for knee osteoarthritis, which can cause joint swelling, stiffness, and even severe pain.

Doctors often prescribe pain relievers, such as acetaminophen, opioids, or nonsteroidal drugs, to help alleviate symptoms. Knee replacement surgery is also an option. However, these treatments are either invasive or could cause a range of unwanted side effects. This is why researchers have decided to investigate whether dietary interventions could relieve some symptoms and signs of knee osteoarthritis.

Robert Sorge, PhD, who is the director of the PAIN Collective in the University of Alabama at Birmingham Department of Psychology, led a randomized, controlled study that compared the efficacy of two diets: one that is low in carbs and one that is low in fat. Sorge and colleges published their findings in the journal Pain Medicine.

Studying the benefits of a low-carb diet

The researchers tested the benefits of low-carb and low-fat diets among 21 adults aged 65–75 who had knee osteoarthritis. The study participants followed either of the two diets or continued to eat normally for a period of 12 weeks.

Every 3 weeks, Sorge and colleagues analyzed the participants' functional pain—which is pain associated with daily tasks—as well as their self-reported pain, quality of life, and level of depression. They also examined the participants' serum blood levels for oxidative stress, both at the beginning and the end of the interventions. Oxidative stress is a chemical imbalance between the production of free radicals and the body's antioxidant properties. Scientists generally consider oxidative stress to be a marker of biological aging. In the current study, lower oxidative stress correlated with less functional pain.

The researchers found that the low-carb diet reduced functional pain levels and levels of self-reported pain. The benefits were particularly noticeable in comparison with the low-fat and regular diets. Finally, when adhering to the low-carb diet, the participants also showed less oxidative stress and lower levels of the adipokine leptin, a hormone with important metabolic functions.

The diet significantly reduces pain

"Our work shows [that] people can reduce their pain with a change in diet," comments the study's lead author. "Many medications for pain cause a host of side effects that may require other drugs to reduce. The beneficial side effects of our diet may be things such as reduced risk for heart disease [and] diabetes and weight loss—something many drugs cannot claim."

"Diet is a great way to reduce the use of pain relievers and to improve general health," Sorge continues. "Diet will never 'cure' pain, but our work suggests it can reduce it to the point where it does not interfere with daily activities to a high degree."

Among people who consume meat, popular low-carb options include "lean meats, such as sirloin, chicken breast, and pork." Fish and eggs are also low in carbs, as are leafy green vegetables, including kale and spinach. Cauliflower, broccoli, nuts, seeds, nut butter, coconut oil, olive oil, and dairy products are also good low-carb options. For those who wish to avoid animal products altogether, tofu and tempeh are great low-carb alternatives.