The Effect of Low-Carbohydrate and Low-Fat Diets on Pain in Individuals with Knee Osteoarthritis

Strath LJ, Jones CD, Philip George A, Lukens SL, Morrison SA, Soleymani T, Locher JL, Gower BA, Sorge RE · Pain Medicine

Three arms, two of them dietary, and only one moved. The low-carbohydrate arm reduced pain intensity and unpleasantness on some evoked functional pain tasks and on self-reported pain, relative to both the low-fat diet and the control. It also lowered serum oxidative stress and leptin against both comparators, and the fall in oxidative stress tracked the fall in functional pain. Having a low-fat arm rather than only a control is what makes this informative — it is not simply a test of dietary attention.

Population

Adults aged 65-75 with knee osteoarthritis

Intervention

A low-carbohydrate diet for 12 weeks

Comparator

A low-fat diet, or eating as usual

Limitations

Described by its authors as a pilot, in adults 65-75 at one centre, over 12 weeks, with self-reported and evoked pain as outcomes and no structural measure. Diet trials cannot be blinded. Whether weight loss accounts for the effect is not resolved.