- Researchers looked at the effects of drinking different types of tea — such as green tea, oolong tea, and black tea — on diabetes risk.
- They found that drinking 1-3 cups of tea slightly reduced type 2 diabetes risk, but that drinking 4 or more cups of tea daily was associated with a 17% lower risk.
- However, more studies are needed to confirm the results.
According to the World Health Organization, around
Some studies have found this to be laborious
Further studies on the effects of tea and dosage on diabetes risk in large populations could inform preventive treatment strategies for diabetes.
Recently, researchers conducted a meta-analysis of 19 cohort studies from eight countries to examine the effects of black, green, and oolong tea consumption on type 2 diabetes risk.
They found that drinking 4 or more cups of tea a day can reduce the risk of diabetes.
“Drinking tea does not appear to be harmful and may provide a small benefit in reducing the risk of diabetes,” said Dr. Kashif M. Munir, associate professor of medicine at the University of Maryland Center for Diabetes and Endocrinology, who was not involved in the study, said Medical news today“Other foods high in polyphenols have shown similar effects.”
The meta-analysis was presented at the annual meeting of the European Association for the Study of Diabetes in Stockholm, Sweden.
For the study, the researchers analyzed data from 5,199 adult participants in the China Health and Nutrition Survey. The participants did not have diabetes at the start of the study and were followed from 1997 to 2009. Their tea consumption was recorded using questionnaires.
Overall, 45.76% of the participants reported drinking tea and 10.04% of the cohort developed type 2 diabetes during the study period.
After accounting for factors such as age, gender and lifestyle factors, the researchers found that tea drinkers had a similar risk of type 2 diabetes to those who did not drink tea.
Next, the researchers conducted a systematic review of 19 cohort studies with 1,076,311 participants examining the association between type 2 diabetes risk and tea consumption.
They were able to examine the relationship between type 2 diabetes risk and consumption of different types of tea—including green tea, oolong tea, and black tea—tea drinking frequency, gender, and residential area.
Researchers found that those who drank 1-3 cups of tea per day had a 4% lower risk of type 2 diabetes than non-drinkers.
However, those who drank at least four cups of tea a day had a 17% lower risk of type 2 diabetes than non-tea drinkers.
Researchers found that their results stayed the same regardless of tea type, gender, and living area. They noted that this suggests that the beneficial effects of tea on diabetes risk may be related to the amount consumed as opposed to other factors.
When asked how drinking tea might reduce type 2 diabetes risk, Dr. Munir:
“Tea is known to contain food polyphenols such as EGCG, which have been shown to reduce insulin resistance and improve endothelial function ([which is] important for regulating the immune response, blood clotting and the widening or narrowing of blood vessels). These effects may have beneficial effects on glucose homeostasis and improve diabetes risk.”
Black tea may also inhibit obesity – a risk factor for diabetes – by reducing the
The researchers concluded that daily tea consumption could reduce the risk of type 2 diabetes.
When asked about the study’s limitations, said Prof Peter Clifton, associate professor of clinical and health sciences at the University of South Australia, who was also not involved with the study MNT Because this study was epidemiological in nature, it can only indicate possible connections.
He added that double-blind, randomized controlled trials of dried tea extract in capsules versus placebos would need to be monitored over several years to yield conclusive results.
“Proposing drinking tea or coffee as a lifestyle measure isn’t going to work because people aren’t going to suddenly change their ingrained habits of not drinking tea. So no reason to give it up, but not much evidence to take it up.”
– Prof. Peter Clifton
dr Munir added that the initial smaller cohort study showed no benefit from tea consumption because observing small effects on large populations often requires larger numbers of participants.
“The meta-analysis included over a million participants from 19 studies and showed benefits of higher tea consumption associated with a lower risk of developing diabetes. Larger studies like this are often needed to tease out a small benefit from a particular food,” he continued.
“However, the limitations are that we don’t know if the food is causal or merely associated with lower rates of diabetes development, and many biases can affect non-randomized trials,” he concluded.