Drinking plenty of green tea and coffee is linked to a lower risk of dying from any cause among people with type 2 diabetes, according to research published in the online journal BMJ Open Diabetes Research & Care. Drinking 4 or more cups of green tea per day plus 2 or more coffee was associated with a 63% lower risk of death over a period of about 5 years, according to the findings.
People with type 2 diabetes are more likely to develop circulatory diseases, dementia, cancer, and bone fractures. And despite an increasing number of effective drugs, lifestyle changes, such as exercise and diet, remain the cornerstone of treatment. When you have diabetes, life is about regulating your blood sugar to keep you healthy. And while many people have to turn to drugs and insulin injections, there is evidence to suggest that drinking green tea could make diabetes easier to manage.
If you have type 2 diabetes and love drinking green tea or coffee, new research suggests that you may be reducing your risk of premature death. But you really need to love these drinks. The study found that having four or more cups of green tea and two cups of coffee a day was associated with a 63% lower risk of death over the average five-year follow-up period. A single cup of coffee or green tea per day may reduce your risk of early death by 12 percent to 15 percent, respectively.
Drinking green tea and coffee daily linked to lower death risk in people with type–2 diabetes. The researchers found that drinking two or more cups of coffee and four or more cups of green tea each day was associated with a 63% lower all-cause mortality.
Previously published research suggests that drinking green tea and coffee regularly may be beneficial to health because of the various bioactive compounds in these beverages. People with type 2 diabetes have cells that are desensitized to insulin, known as insulin resistance. This, and the fact that the pancreas often stops releasing enough insulin, makes it difficult to control their blood sugar levels.
However, few of these studies have been conducted in people with diabetes. The researchers therefore decided to explore, separately and in combination, the potential impact of green tea and coffee on the risk of death among people with the condition. The health of 4923 Japanese people (2790 males, 2133 females) with type 2 diabetes (average age 66) was monitored for an average of just over 5 years.
They were all enrolled in the Fukuoka Diabetes Registry, a multicentre prospective study on the effects of drug treatment and lifestyle on the lifespan of patients with type 2 diabetes. They each filled out a 58-item food and drink questionnaire, which included questions about how much green tea and coffee they were drinking every day. They also provided background information on lifestyle factors, such as regular exercise, smoking, alcohol consumption and nightly sleep.
Measurements of height, weight and blood pressure, as well as blood and urine samples, were also taken to check for potential underlying risk factors. Some 607 of the participants did not drink green tea; 1143 drank up to a cup a day; 1384 drank 2-3 cups; and 1784 drank 4 or more. Nearly 1,000 (994) of the participants did not drink coffee; 1306 drank up to 1 cup daily; 963 drank a cup every day; and 1660 drank 2 or more cups.
During the monitoring period, 309 people (218 men, 91 women) died. The main causes of death were cancer (114) and cardiovascular disease (76). Compared with those who drank neither beverage, those who drank one or both had lower odds of dying from any cause, with the lowest odds associated with drinking higher quantities of both green tea and coffee.
Drinking up to 1 cup of green tea every day was associated with a 15 percent lower death rate; while drinking 2-3 cups was associated with a 27 percent lower death rate. Getting through 4 or more cups a day was associated with 40% lower odds. Among coffee drinkers, up to 1 cup per day was associated with 12 per cent lower odds; while 1 cup per day was associated with 19 per cent lower odds. And 2 or more cups were associated with 41 percent lower odds.
The risk of death was even lower for those who drink green tea and coffee every day: 51 per cent lower for 2-3 cups of green tea plus 2 or more coffee; 58 per cent lower for 4 or more cups of green tea plus 1 cup of coffee every day; and 63 per cent lower for 4 or more cups of green tea and 2 or more cups of coffee every day.
This is an observational study, and as such, the cause cannot be established. And the researchers point to a number of caveats, including the dependence on subjective assessments of the quantity of green tea and coffee drunk. Nor was any information collected on other potentially influential factors, such as household income and educational attainment. And the green tea available in Japan may not be the same as found elsewhere, they add.
The biology behind these observations is not fully understood, the researchers explain. Green tea contains several antioxidants and anti-inflammatory compounds, including phenols and theanine, as well as caffeine. Coffee also contains a number of bioactive components, including phenols. As well as its potentially harmful effects on the circulatory system, caffeine is thought to alter the production and sensitivity of insulin.
“This prospective cohort study has shown that increased consumption of green tea and coffee has been significantly associated with reduced all-cause mortality: the effects may be additive,” the researchers concluded.