Grapes and Joint Health

Abstract

Osteoarthritis (OA) is the most common arthritic disease worldwide. It is a complex chronic disease that reflects age-related degeneration of joint tissues in response to mechanical stress or injury. Normal repair and inflammatory responses follow and contribute to a cycle of further stress and damage, leading to inflammation, chronic pain, and impairment of mobility. The inflammation seen in OA is directly responsible for much of the structural degeneration and many of the clinical symptoms such as joint swelling, synovitis, and associated pain and stiffness. Because traditional therapy can be expensive and invasive and carries significant adverse effects, people are increasingly opting for alternative and naturally derived treatments. Polyphenols are phytochemicals present in fruits and vegetables that are associated with anti-inflammatory, antioxidant, cardioprotective, and chemopreventive properties, making them an ideal subject of research for arthritis and joint health applications. There is evidence that dietary polyphenols provide benefit for both OA and rheumatoid or other forms of inflammatory arthritis. The mechanism of action for the observed effects appears to be downregulation of the inflammatory cytokines, influencing antioxidant or anti-inflammatory pathway signaling, and/or estrogen receptor activation. Study results have shown many positive effects of polyphenols in both in vitro in chondrocytes and tissue explants, as well as in vivo in animal models. Two human studies suggest that grape consumption with its bioactive constituents may also reduce inflammation and influence OA outcomes. Specifically, daily consumption of a freeze-dried grape powder (FDGP) with its bioactive constituents may reduce symptoms of pain and possibly impact a biomarker of cartilage metabolism in individuals with self-reported knee OA. This is in keeping with the literature that has shown decreases in self-reported OA symptoms with soy isoflavones and tart cherry polyphenols. Other studies are currently underway that may confirm an effect of FDGP on arthritis and other chronic diseases in humans.