Strawberries Improve Pain and Inflammation in Obese Adults with Radiographic Evidence of Knee Osteoarthritis

Abstract

Osteoarthritis (OA), the most common form of arthritis, is a significant public health burden in U.S. adults. Among its many risk factors, obesity is a key player, causing inflammation, pain, impaired joint function, and reduced quality of life. Dietary polyphenols and other bioactive compounds in berries, curcumin, and tea have shown effects in ameliorating pain and inflammation in OA, but few clinical studies have been reported. The purpose of the present study was to examine the effects of dietary strawberries on pain, markers of inflammation, and quality of life indicators in obese adults with OA of the knee. In a randomized, double-blind cross-over trial, adults with radiographic evidence of knee OA (n = 17; body mass index (BMI): (mean ± SD) 39.1 ± 1.5; age (years): 57 ± 7) were randomized to a reconstituted freeze-dried strawberry beverage (50 g/day) or control beverage daily, each for 12 weeks, separated by a 2-week washout phase (total duration, 26 weeks). Blood draws and assessments of pain and quality of life indicators were conducted using the Visual Analog Scale for Pain (VAS Pain), Measures of Intermittent and Constant Osteoarthritis Pain (ICOAP), and Health Assessment Questionnaire-Disability Index (HAQ-DI) questionnaires, which were completed at baseline and at weeks 12, 14, and 26 of the study. Among the serum biomarkers of inflammation and cartilage degradation, interleukin (IL)-6, IL-1β, and matrix metalloproteinase (MMP)-3 were significantly decreased after strawberry vs. control treatment (all p < 0.05). Strawberry supplementation also significantly reduced constant, intermittent, and total pain as evaluated by the ICOAP questionnaire as well as the HAQ-DI scores (all p < 0.05). No effects of treatment were noted on serum C-reactive protein (CRP), nitrite, glucose, and lipid profiles. Dietary strawberries may have significant analgesic and anti-inflammatory effects in obese adults with established knee OA.

Health effects of a low-inflammatory diet in adults with arthritis: a systematic review and meta-analysis

“…Of the 453 citations retrieved from multiple sources, seven articles (19,21,22,33,(42)(43)(44) met the eligibility criteria ( Fig. 1).…”

Intra Articular Ozone Reduces Serum Uric Acid and Improves Pain, Function and Quality of Life in Knee Osteoarthritis Patients: A Before-and-After Study

“…Biomarkers of inflammation (especially CRP and IL-6) and biomarkers of cartilage degradation (including matrix metalloproteinases), have been previously related to pain and progression in OA (18)(19)(20)(21). Besides, non-steroidal anti-inflammatory drugs (NSAIDs) and dietary bioactive compounds (curcumin, ginger, green tea polyphenols, and strawberries) have been shown to be effective in the management of pain symptoms and in reducing inflammatory biomarkers of OA (22). Unfortunately, most of such studies for the management of knee OA are limited in number and short in duration; moreover, they mainly evaluate pain and function but no inflammation biomarkers.…”

Chondroprotective Properties of Human-Enriched Serum Following Polyphenol Extract Absorption: Results from an Exploratory Clinical Trial

“…Moreover, these ex vivo results perfectly match with literature data from other clinical trials regarding anti-inflammatory and antioxidant capabilities of "polyphenol strategies". To date, a reconstituted freeze-dried strawberry beverage (50 g/day) given to obese adults with radiographic evidence of knee OA significantly lowered serum biomarkers of inflammation including (IL)-6, IL-1 β, and cartilage degradation mediators including matrix metalloproteinase (MMP)-3 [37]. Forty g of freeze-dried blueberry powder given daily for four months to adults with symptomatic knee OA significantly decreased (WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index) total score and subgroups, including pain, stiffness, and difficulty to perform daily activities [38].…”