Nutrients and immune-inflammatory response in RA

Rheumatoid arthritis (RA) is characterised by a systemic immune-inflammatory response, in genetically susceptible individuals exposed to environmental and endogenous triggers, including specific nutrients.1 The major pathways in RA are characterised by an intense inflammatory response, involving impaired immunoregulatory processes and the production of different proinflammatory mediators.2 Research on possible risk factors has traditionally focused on triggers setting off disease, such as microbial/viral agents, cigarette smoking and environmental pollution, hormonal imbalance and chronic stress, but with less focus in the past few decades on nutritional factors that can influence disease onset, progression and outcomes, possibly through epigenetic mechanisms.2

More recently, simple and daily dietary factors have been implicated in the development of RA, even directly through triggering inflammatory pathways: for example, the recent evidence that increased sodium chloride salt (figure 1), activates proinflammatory macrophages (M1), Th17 cells and decrease T-regulator cells, all crucial players in RA pathogenesis.3 In addition, sodium excretion was recently found higher in patients with early RA than in matched controls.4

Other interferences exerted by nutrients like cocoa, ginseng or capsaicin (pepper) on the RA pathways and mediators are reported in figure 1 and discussed in greater detail below.

Despite accumulating evidence over time, the important role that the diet plays on human health in general and more specifically in chronic conditions such as RA, has been subject to much controversy. This has had direct impact on the most important stakeholders, the patients, who are the most frequent active seekers and ‘consumers’ of this crucial information.

Evidence for the possible role of different ‘fatty diets’ in models and patients with RA

An important reason for rheumatologists needing to pay attention to nutrition is in order …