Impact of diurnal intermittent fasting during Ramadan on inflammatory and oxidative stress markers in healthy people: Systematic review and meta-analysis

Studies on the impact of diurnal intermittent fasting during Ramadan on inflammatory and oxidative stress markers have been limited and yielded contradictory results. Therefore, we performed a systematic review and meta-analysis to comprehensively examine changes in inflammatory and oxidative stress markers in healthy people before and after Ramadan. Databases searched were: PubMed/MEDLINE, ProQuest Medical, Web of Science, Scopus, EBSCOhost, Science Direct, CINAHL, Cochrane, and Google Scholar. The reference lists of identified papers were also screened. There was no date restriction for papers. The studied inflammatory markers were: interleukin (IL)-1, IL-6, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP)/high sensitivity CRP (hs-CRP). The studied oxidative stress marker was malondialdehyde (MDA). We identified 12 studies (involving 311 participants) conducted in eight countries: Iran (K = 3), Turkey (K = 2), the Kingdom of Saudi Arabia (K = 2), Jordan (K = 1), the United Arab Emirates (K = 1), Denmark (K = 1), the Netherlands (K = 1), and Indonesia (K = 1). Diurnal fasting during Ramadan resulted in very small reductions in IL-1 (Hedge's g = 0.016), CRP/hs-CRP (Hedge's g = 0.119), and MDA (Hedge's g = 0.219), and small reductions in TNF-α (Hedge's g = 0.371) and IL-6 (Hedge's g = 0.407). These results suggest diurnal intermittent fasting during Ramadan provides some protection against elevated inflammatory and oxidative stress markers. Therefore, it may offer an opportunity to reduce low-grade systemic inflammation and oxidative stress, and subsequent adverse health effects in healthy people.