HEALTHEFFECTSOF BLACK TEA AND THE IRMODULATION BY MILK

Abstract

There is a very long history of association of teawith health; it evolved fromdomain ofmedicine in ancient China to its current global status of beverage having the largest consumption after water.While there is a strong epidemiological link of tea consumption with the risk of cancer and heart diseases, the causal relationships are just beginning to unravel. Flavonoids are one of themost active ingredients in tea.Both the nature and amount of flavonoids available to human body after the consumption of tea, therefore, become critical in defining the efficacy of tea. Multiple factors which govern bioavailability of flavonoids include quantity and quality of available flavonoids in tea, genetic characteristics of tea consuming population, themanner (brewing vs. boiling) in which tea infusion is prepared, and perhaps also by whether or not milk and the amount of milk is added to tea. The addition of milk may have significant implications in bioavailability of tea flavonoids in south Asia where tea infusion is mostly prepared by boiling (in comparison to brewing) tea leaves in presence ofmilk for time ranging fromfewto severalminutes. In the absence of any significant epidemiology or clinical study fromthe region, the supporting evidence for public health contribution of tea relies on the evidence derivedmainly fromwestern countries for black tea and Japan and China for green tea. In this article, we reviewthe relevant literature available on influence ofmilk on the health effects of tea. The available literature indicates that amount of milk in tea, if kept below 25%, does not significantly affect bioavailability of catechins in blood plasma. Though milk may delay the time taken to raise plasma antioxidant potential, the levels still reach significantly higher to that of baseline.There is a need, particularly in SouthAsia, to initiate further studies to generate data, which at this time seem insufficient for any evidence based nutritional recommendation on addition of milk to tea especially when the amount of added milk is high.