Tea consumption is associated with a reduced risk of type 2 diabetes, according to a recent review of studies authored by Dr Catherine Hood from The Tea Advisory Panel (TAP). Among the 12 studies identified for this latest review, 11 showed a positive effect of tea consumption on reducing the risk of diabetes.
Looking at the studies in summary, Dr Hood from TAP notes: “In the Chinese Singapore Study among 36 908 participants age 45-74 years, consumption of more than one cup of tea daily reduced the risk of diabetes by 14 per cent.
“The Dutch arm of the big European Prospective Investigation into Cancer and Nutrition (EPIC) which was followed up for 10 years found a bigger reduction in risk of diabetes. In this study total daily consumption of three cups of tea, three cups of coffee or a combination of tea and coffee reduced the risk of type 2 diabetes by approximately 42 per cent.
“The BMJ published a study evaluating the relationship between black tea consumption and key health indicators across the world. Health indicators covered were respiratory diseases, infectious diseases, cancer, cardiovascular diseases and diabetes at a global level. This study found a significant linear correlation between high black tea consumption and low diabetes prevalence in the world.”
Dr Catherine Hood adds: “The development of diabetes is associated with a number of oxidative and inflammatory biological markers in the blood such as C-reactive protein. In an intervention trial involving 46 patients with type 2 diabetes different amounts of black tea extract were given over a 4-week period and biochemical assessments performed at the end of each week. Two cups of black tea suppressed blood levels of malondialdehyde, a marker of oxidation, while C-reactive protein, a marker of inflammation, decreased following intake of 4 cups of black tea extract.
“In a further study looking at the relationship between tea and coffee and inflammatory markers as well as markers of blood glucose metabolism, green tea consumption was not associated with markers of glucose metabolism but was again associated with reduced C-reactive protein suggesting a beneficial effect of tea on inflammation.”
Dr Tim Bond from TAP notes further: “Research with commercial teas has shown that green and black tea inhibited oxidative compounds and enzymes that digest carbohydrate. Green tea had the greatest inhibitory effect but black tea was also associated with benefit. A trial in 48 people with diabetes who took tea extracts daily for 3 months found no blood sugar lowering effect of green and black tea.
“Overall these studies indicate a very promising association between tea consumption and diabetes which if confirmed in further studies indicates further health benefits for tea beyond the well established cardiovascular benefit. Diabetes is affecting increasing numbers of the population and potentially could cost 17 per cent of the health care budget. Drinking 3-4 cups of tea each day has benefits for the heart and could also have benefits for glucose metabolism, inflammatory markers and reducing the risk of diabetes.”