The health benefits of green tea are widely known, but coffee? Not so much. Now exciting new research from Japan shows both popular beverages can benefit people with diabetes in life-saving ways. So grab a cup of tea or coffee and let’s dig into these fascinating findings.
For many years, scientists have observed that people who consume green tea and coffee experience a lower risk of death from cardiovascular disease as well as all other causes.1
Scientists have speculated that these benefits are due to the antioxidant and anti-inflammatory compounds found in both beverages.
Coffee and Tea: Chock Full of Disease-Fighters
Green tea’s claim to fame is its catechin content. These antioxidants have been shown to fight cell damage that causes cancer. Coffee, on the other hand, contains chlorogenic acids, another hardworking antioxidant that’s been linked to improved fat metabolism and lower cholesterol levels.2
Past research has suggested that both of these compounds might also improve glucose control and insulin sensitivity.
Japanese researchers from Kyushu University, Fukuoka Dental College, and Hakujyuji Hospital decided to see if they could bring more clarity to the issue.
In fact, they took their research one step further and investigated the effect of coffee and green tea on the risk of death for people with diabetes.
Researchers Examined Nearly 5,000 Diabetics
The researchers performed a huge five-year observational study during which they tracked the health of almost 5,000 people in Japan with Type 2 diabetes.
The participants completed questionnaires focusing on lifestyle and food and drink habits. In particular, they were asked how much green tea and coffee they drank daily.
The study showed that Type 2 patients who drank more than one cup of green tea or coffee daily decreased their odds of dying from ANY cause compared to their peers who didn’t drink these beverages.
“Higher green tea and coffee consumption was significantly associated with decreased all-cause mortality in people with type 2 diabetes," the researchers stated.
And it seems the more you drink, the merrier. The diabetics who were longest lived in the group were the ones who drank significant amounts of these beverages.
Coffee or Tea? Researchers Say Drink Both!
Looking at folks who just drank coffee, researchers found that drinking two or more cups per day was associated with a 41 percent lower chance of death.
Meanwhile, green tea drinkers who drank four or more cups a day experienced a 40 percent lower risk of death. (Green tea has much less caffeine than coffee, so generally the tea drinkers are able to consume a lot more without getting too wired.)
But what’s really interesting are the findings about those people who enjoyed both beverages daily. Researchers found their health benefits were even better!
- Two to three cups of green tea plus two or more cups of coffee — 51 percent lower mortality risk
- Four or more cups of green tea plus one cup of coffee — 58 percent lower mortality risk
- Four or more cups of green tea and two or more cups of coffee — 63 percent lower mortality risk
If I drank that much I would be flying without the benefit of a plane, and wide awake staring at the ceiling at 3:00 in the morning. But some people seem to be able to tolerate it. You have to judge for yourself – and be aware that you can feel the effects of these beverages 12 hours later.
But, in the interest of science, let’s continue.
Observational Studies Aren't The End All Be All
It’s important to note that this is an observational study—meaning it relies on self-reporting on the quantities of green tea and coffee consumed. Observational studies are reliable, but sometimes people’s memories when they go to report their habits aren’t.
Additionally, this study is focused on the Japanese population, so its findings may not always apply to people in the U.S. I think it’s worthwhile to mention that in many Asian cultures it’s common for people to drink larger amounts of tea throughout their lives than we do here in the U.S.
Dr. Minisha Sood, an endocrinologist at Lenox Hill Hospital in New York City, brought up another point, saying, “It is also important to be cautious when interpreting the findings of this study because this group of patients was, on average, non-obese patients with controlled blood pressure.3” In other words, they didn’t have some of the other co-morbidities that can often run hand in hand with diabetes and, on their own, can raise your risk of death. You might say they were relatively healthy diabetics.
That being said, drinking coffee or green tea may benefit people who do have these other health problems. In fact, I think green tea in particular would, but that’s just my opinion based on past research.
Another thing -- if you do battle high blood sugar, I’d encourage adding coffee and green tea to a diet that’s already rich in fresh vegetables and lean meat with minimal processed food.
If you want to read more about the Japanese study, see their findings in the British Medical Journal Open Diabetes Research & Care.4
- https://www.health.harvard.edu/staying-healthy/tea-a-cup-of-good-health
- https://www.ahajournals.org/doi/pdf/10.1161/STROKEAHA.111.677500#:~:text=In this study%2C higher green,%2C and its sub%2D types
- https://www.usnews.com/news/health-news/articles/2020-10-22/coffee-green-tea-might-extend-life-for-folks -with-type-2-diabetes
- https://drc.bmj.com/content/8/1/e001252
