Investigating Racial Differences in Diet Benefits for Knee Osteoarthritis

Knee osteoarthritis (OA) is the most prevalent form of arthritis and race is a risk factor for poor outcomes. African-Americans (AAs) report greater OA-related disability and pain severity compared to their Non-Hispanic White (NHW) counterparts. These disparities are reinforced through social and biological mechanisms, ultimately resulting in dramatic racial disparities in pain experience and associated quality of life. Low-carbohydrate diets (LCDs) reduce inflammation and pain independent of weight loss, but significant racial differences exist in metabolism that are rarely addressed in diet interventions. The overall objective of the proposed study is to determine whether the beneficial effects of an LCD for knee OA pain are related to race. The investigators will recruit 20 adult women (65-75) with knee OA with equal representation across racial groups (10 AA, 10 NHW). Following one week of diet and pain self-report, the investigators will assess quality of life, depression, experienced pain and evoked pain. Participants will be placed on a LCD wherein all meals and snacks will be delivered weekly after consult with study personnel. Participants will return every 3 weeks for testing during the 6-week intervention with blood drawn at baseline and at the conclusion of the 6-week diet. Blood will be assayed for oxidative stress markers. This will be the first assessment of racial differences in the efficacy of a LCD to reduce knee OA pain. Objective 1: To determine whether the LCD reduces pain after 6 weeks. Hypothesis: The LCD will significantly reduce evoked and self-reported pain. Objective 2: To determine whether the benefits of the LCD differ based on race. Hypothesis 1: The LCD will reduce evoked and self-reported pain more in AA than in NHW. Hypothesis 2: AAs will experience greater improvements in depression, quality of life, pain interference and show more weight loss than NHWs. Objective 3: To determine whether the LCD has a differential impact on oxidative stress by race. Hypothesis 1: The LCD will significantly reduce oxidative stress over 6 weeks. Hypothesis 2: AAs will show greater reductions in oxidative stress than NHWs. The reduction in oxidative stress will be correlated with reduction in evoked pain.