Nutrition, Weight Management and Rheumatic Disease

Every meal represents a small repeated exposure that may influence inflammation, body weight, metabolic health, physical function, and ultimately quality of life in rheumatic disease. Hello, I'm Dr. Elena Filipou, a registered dietitian and associate professor in nutrition and dietetics at the University of Nicosia in Cyprus. In clinical practice, we often hear the question, what should I eat to reduce inflammation? And while it sounds simple to answer, the scientific response is more complicated.

Firstly, we should establish that diet is certainly not a substitute for disease-modifying therapy, but it could certainly be a modifiable lifestyle factor that can play important direct and indirect roles in rheumatic disease management. This is because what we eat does not only have an influence on body weight and composition, but it also supplies a combination of nutrients with potentially beneficial or even detrimental effects on overall health. Diet also influences cardiometabolic risk, of course bone health, pain and physical function as well as mental and other outcomes.

Today I will briefly cover three areas: the evidence on diet quality and dietary patterns in relation to rheumatic disease, the importance of excess adiposity and sarcopenia, and how we can translate this evidence into practical advice.

So let's start with the first point, dietary quality. A 2025 systematic review and meta-analysis found that healthier dietary patterns were associated with a lower risk of developing rheumatoid arthritis, although of course the evidence was observational and a bit heterogeneous. Similar associations between greater Mediterranean diet adherence and more favorable disease-related outcomes have been reported in systemic lupus, psoriatic arthritis, and idiopathic inflammatory myopathies. So the signal is fairly consistent. Overall diet quality appears to matter, although causality cannot be assumed.

One way of examining dietary quality is through the dietary inflammatory index, or otherwise referred to as DII. In the six-year Japanese TOMORROW study, people with RA whose diet shifted towards a more anti-inflammatory DII had approximately three-and-a-half-fold greater odds of maintaining low disease activity. Associations between a more inflammatory diet and poorer outcomes have also been reported in osteoarthritis.

And as we know, observational studies demonstrate associations rather than causation, and dietary intervention trials remain challenging because of issues such as adherence. Nevertheless, in a 2021 systematic review of 70 dietary intervention studies in rheumatoid arthritis, we found promising signals for omega-3 fatty acids, vitamin D, sodium restriction, and the Mediterranean diet, particularly where shared mechanisms such as chronic inflammation are involved.

So, which dietary pattern should we recommend? The Mediterranean diet is probably the most clinically defensible. It's rich in legumes, fruits, vegetables, nuts and seeds, whole grains, of course extra virgin olive oil and fish, and less red and processed meat and highly processed foods. I would also add that the evidence suggests an extra intake of omega-3 fatty acids either from more frequent consumption of oily fish such as salmon, sardines, sea bream, sea bass, walnuts and chia seeds, or through supplementation, or a combination of both. And importantly, randomized trials in rheumatoid arthritis support this approach.

Some examples include the SKJOLSTAM trial, which is a 12-week Mediterranean diet in patients with RA, and this produced a 0.56 point reduction in DAS-28 together with improved physical function. Another example is the ADIRA crossover trial, which was an anti-inflammatory diet rich in fatty fish, whole grains, fruit, vegetables and nuts. And this study produced a modest improvement in DAS-28 ESR among those participants that completed both dietary protocols. And more recently, the MEDRA trial found better physical function and quality of life following a Mediterranean diet intervention compared with healthy eating advice, although importantly, both groups improved.

So my message to rheumatologists and patients is very simple. The Mediterranean diet has emerging evidence in rheumatic disease, substantial wider cardiometabolic benefits, and is a sensible pattern to recommend alongside effective rheumatological treatment.

Now let us move on to talk about body weight. Obesity is not simply another cardiovascular comorbidity in rheumatology. In the UK and ERAN cohorts, among the longest running and most substantial rheumatoid arthritis inception cohorts involving more than 2,000 people with early RA, Dr. Nikiphorou and colleagues showed that obesity was associated with approximately half the odds of achieving low DAS-28 at two years, as well as poorer function and physical quality of life. Intervention studies also suggest that weight reduction can improve clinically relevant outcomes. We have evidence in psoriatic arthritis, RA, osteoarthritis and others. So
excess deposited deserves our attention for sure. Body mass index is a useful starting point but it should not be the whole assessment. We need to add a measure of central adiposity for sure. Waist to height ratio is particularly practical and the ratio above 0.5 suggests excess central adiposity. And here the simple patient message is try to keep your waist below your height. If weight loss is appropriate, a sustainable energy deficit with an initial target of approximately 5 to 10% weight reduction is a reasonable target.

But in rheumatology we should ask not only how much weight is being lost but also what tissue is being lost because muscle matters. Sarcopenia is relatively common in RA with meta-analytic estimates of approximately 24 to 30% depending on the diagnostic criteria used, and sarcopenic obesity is particularly important because BMI can miss it completely. It is also associated with poor physical function.

So I would ask three questions. Does this patient have excess adiposity? Do they have adequate muscle? And are they functionally strong? The SARC-F is a very quick screening tool covering strength, walking, rising from a chair, climbing stairs and falls.

Therefore, when weight loss is recommended, protecting muscle must be part of the prescription. In older adults and particularly those at risk of sarcopenia, around 1.2 to 1.5 grams of protein per kilogram per day is recommended, but of course individualized according to renal function, nutritional status and body size, together of course with resistance exercise at least twice per week and aerobic activity as tolerated.

All of this is also where multidisciplinary care matters. Patients requiring individualized dietary treatment, weight management or sarcopenia assessment should be referred to a registered dietician and managed. This approach is broadly consistent with recommendations from EULAR, the French Society for Rheumatology and the American College of Rheumatology, which support healthy dietary patterns including Mediterranean style eating and appropriate weight management as components of rheumatological care.

So I will finish with four key take-home messages. The first one is improve overall diet quality, with support from a registered dietician where needed. The second is that the Mediterranean diet is a sensible evidence-based dietary pattern to recommend. Third, identify and manage excess adiposity where appropriate. And lastly, when patients lose weight, protect muscle through adequate protein and resistance exercise.

Ultimately, the goal is not simply weight loss. It is a healthier diet, healthier body composition, less pain, and better overall health. Thank you very much for your attention.