The beneficial effects of tea on immune function and inflammation: a review of evidence from in vitro, animal, and human research

Review Article
Mark Hamer Department of Epidemiology and Public Health, University College London, WC1E 6BT London, UK
Nutrition Research 27 (2007) 373–379
Abstract
...In summary, there is evidence to suggest that tea may have beneficial effects on certain immune parameters, which has implications for improving gut health and resistance against infections such as the common cold. However, further evidence from human studies, which control for potential confounding from lifestyle and biological factors, is required before strong conclusions can be made regarding the association between tea and immune function.