A study published in the journal BMJ Open Diabetes Research & Care found that green tea lowered the death risk from type 2 diabetes. The results showed that 4 or more cups of tea plus 2 or more of coffee daily lowered death risk by 63% over 5 years. Type 2 diabetes increases the risk of developing diseases such as dementia, cancer, heart disease, and neuropathy. Many pharmaceuticals exist to treat diabetes, but doctors still widely recommend lifestyle changes such as diet and exercise.
Many studies have been done on the benefits of green tea and coffee on health due to their abundance of antioxidants. However, few studies in the past have focused specifically on how these beverages affect people with diabetes. Researchers analyzed how green tea and coffee, separately and combined, affected those with diabetes’ death rates.
The green tea study
The team tracked the health of 4923 Japanese people, average age 66, with type 2 diabetes for around 5 years. All had been listed in The Fukuoka Diabetes Registry, a study that looks at how drug and lifestyle treatments impact the lifespan of type 2 diabetes patients. In addition, they filled out a 58-item food and drink questionnaire, which asked questions about their daily green tea and coffee consumption. They also reported information on other lifestyle factors such as exercise routine, smoking habits, alcohol consumption, and sleep duration/quality.
Researchers took their height, weight, and blood pressure, as well as blood and urine samples to check for any other risk factors. The data revealed that 607 participants didn’t drink green tea; 1143 drank a cup daily; 1384 drank 2-3 cups, and 1784 drank 4 or more. As for coffee, 994 participants didn’t drink it, and 1306 had up to 1 cup a day, 963 drank exactly a cup per day, and 1660 had 2 or more cups.
During the study period, 309 people (218 men, 91 women) passed away, mainly due to cancer (114) and cardiovascular disease (76). The people who drank one or both beverages had a lower risk of all-cause mortality than those who drank neither. Drinking the highest amounts of tea and coffee resulted in the least risk of early death. In fact, drinking up to 1 cup of green tea per day carried a 15% lower risk of death.
People who consumed 2-3 cups of tea daily had 27% lower odds of dying. But those who drank 4 or more had a 40% reduced risk. The coffee-drinking group had a 12% lower risk of dying when they drank up to 1 cup daily. At least a cup a day carried a 19% lower risk, and 2 or more lowered the chances by a whopping 41%.
Drinking both tea and coffee lowered the risk of early death from type 2 diabetes the most
Those who consumed both green tea and coffee each day reaped the most benefits. They had a 51% lower chance of early death when they had 2-3 cups of green tea plus 2 or more coffee. Those who had 4 or more cups of tea plus a coffee cup daily had a 58% lower chance. It lowered the odds to 63% when they had both 4 or more cups of tea and 2 or more of coffee every day.
Disclaimers from the study
The researchers can’t directly link tea and coffee drinking to a lower risk of death from type 2 diabetes. Because it was an observational study, they can only speculate. Also, since the participants self-reported tea and coffee consumption, this may have altered the results.
Furthermore, they didn’t analyze other information that could’ve influenced the study, such as household income or educational background. Finally, the green tea in Japan may have been different from teas found in other parts of the world.
The researchers will have to perform future studies to uncover more about the biology behind the results. However, the high antioxidant and anti-inflammatory content in green tea could explain why it benefits people with type 2 diabetes. Green tea includes phenols and theanine, power anti-inflammatories, as well as antioxidants like EGCG. This helps prevent cell damage and reduce inflammation; the high caffeine content boosts brain function as well.