Osteoarthritis and nutrition. From nutraceuticals to functional foods: a systematic review of the scientific evidence

Osteoarthritis (OA) is one of the most prevalent and disabling chronic diseases affecting the elderly. Its most prominent feature is the progressive destruction of articular cartilage which results in impaired joint motion, severe pain, and, ultimately, disability. Its high prevalence and its moderate-to-severe impact on daily life pose a significant public health problem [1].Today, a cure for OA remains elusive. The management of OA is largely palliative, focusing on the alleviation of symptoms. Current recommendations for the management of OA include a combination of nonpharmacological interventions (weight loss, education programs, exercise, and so on) and pharmacological treatments (paracetamol, nonsteroidal anti-inflammatory drugs [NSAIDs], and so on) [2]. Among these pharmacological treatments, NSAIDs, despite serious adverse effects associated with their long-term use, remain among the most widely prescribed drugs for OA [3]. In this context, there is a need for safe and effective alternative treatments while the absence of any cure reinforces the importance of prevention.Such prevention and alternative treatments could come from nutrition. It is now increasingly recognised that, beyond meeting basic nutritional needs, nutrition may play a beneficial role in some diseases [4]. OA as a chronic disease is the perfect paradigm of a pathology the treatment of which could be addressed by nutrition. By nature, nutrition is better positioned to provide long-term rather than short-term health benefits. This is because, in most cases, a nutritional compound has only limited effects on its biological target and relevant and significant differences are reached only over time through a build-up effect in which daily benefits add up day after day. For this reason, and because the time window for intervention is longer in chronic diseases, such diseases should, in theory, benefit more from nutrition than do acute diseases. In addition, because the mechanisms of cartilage d