Background/Purpose: There have been over 777 million cases of acute COVID-19 infections worldwide as of April 2025. Although many patients recover, an estimated 10-30% of patients continue to experience a constellation of symptoms labelled “Long COVID” or PASC. Major symptoms include fatigue, cognitive dysfunction, post-exertional malaise, and sleep disturbances. Exact pathophysiology of PASC remains unclear but there are data suggesting a potential role of inflammation and autoimmunity in persistence of symptoms. In the absence of effective treatments, patients are inquiring about the role of diet given burgeoning data linking microbiome dysbiosis to dysregulated host immune responses and autoimmune diseases. We assessed the feasibility of a 12-week anti-inflammatory diet (Long COVID Anti-Inflammatory, LC-ITIS) among patients with PASC and explored diet-induced changes in clinical symptoms and inflammatory makers.

Methods: Patients with a confirmed COVID-19 infection and persistence of >2 of the 3 new symptoms (sleep disturbances, brain fog, fatigue > 5 on VAS) for > 12 weeks after the infection were recruited. LC-ITIS diet was similar to previously established RA anti-inflammatory (RA-ITIS) diet from our group which has shown correlation between gut microbiome/metabolome and clinical response [Coras R et al. Clin Transl Med 2022;12:e959]. LC-ITIS diet emphasized foods rich in anti-inflammatory nutrients and those with favorable omega-6:Omega-3 fatty acid profile (e.g. flax/chia seeds, miso). Foods such as highly processed foods, added sugar, and nightshade vegetables were restricted. Clinical outcomes, dietary adherence, and inflammatory makers were measured (Table 1). Data were analyzed using ANOVA and mixed-effects model. Statistical analyses were performed in SPSS.

Results: Two patients dropped out at Week 0 (Wk0) before starting the diet. All remaining 21 patients completed 2 weeks of LC-ITIS diet with pre- and post-assessments. Majority (71%) completed 12 weeks of diet and assessments. Patients were 66% women, 57% Caucasians, and 24% Hispanics with a mean age of 53.3 +15 (range 25-78). By the end of the study, 50% reported that they changed their dietary habits significantly. The self-reported adherence rate was high at 91% at Wk2 and maintained at 94% through Wk12 ( >6 on a 0-10 scale; moderate to very well). The mean BMI decreased from 28.8 to 27.8 over 12 weeks. Many, 69% and 49%, found diet instruction and diet easy/very easy to follow, respectively. There were significant clinical improvements in fatigue, sleep, cognitive function, and depressive mood with LC-ITIS diet (Table 2). Inflammatory marker results are excluded in this report.

Conclusion: This is the first pilot study assessing the effect of anti-inflammatory diet on clinical outcomes in patients with PASC. The diet adherence rate was very high among these patients despite significant fatigue and brain fog. Our initial findings demonstrate feasibility and potential symptom relief benefits of anti-inflammatory diet in a disease with no effective treatment. This finding should be evaluated in a larger randomized controlled trial.

Table 1. LC-ITIS Diet Regimen and Assessment Timeline

Table 2. Clinical Outcomes

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-feasibility-and-clinical-effects-of-anti-inflammatory-diet-intervention-in-patients-diagnosed-with-long-covid-post-acute-sequelae-of-sars-cov-2-pasc/