Black Tea and Systemic Inflammation: A Narrative Review of Inflammatory Markers and Their Role in Disease Modulation

It is well established that chronic oxidative stress can drive systemic inflammation, contributing to the development of conditions such as asthma, type 2 diabetes, metabolic syndrome, cardiovascular disease, and osteoarthritis. Black tea is recognised for its bioactive anti-inflammatory properties, largely due to its diverse profile of bioactive compounds, including theaflavins, thearubigins, catechins, L-theanine, and quercetin. The present narrative review examined evidence from 11 meta-analyses, systematic/umbrella reviews, and 11 randomised controlled trials (n = 22 studies) published over the past 20 years, focusing specifically on black tea (with or without milk) and systemic inflammation. Most studies administered black tea intake at levels equivalent to 3 - 4 cups per day. Overall, black tea appears to exert anti-inflammatory and antioxidant effects, particularly in individuals with elevated baseline inflammation. These effects were most evident in longer-duration trials and those targeting populations with existing inflammatory conditions. Given the recognised role of diet in modulating inflammation, incorporating black tea and its array of bioactive compounds into daily routines may have public health relevance. Future research should prioritise longer and larger trials that reflect typical consumption patterns and expand the range of health outcomes assessed.