Type 2 diabetes is a chronic condition whereby the insulin your pancreas produces is not sufficiently taken up by the cells. This is known as insulin resistance. The primary role of insulin is to stabilise blood sugar – the main type of sugar found in blood. Stripped of this mechanism, blood sugar levels can rise to dangerous levels, sparking a series of complications.
The goal of diet is to reduce insulin resistance and lower high blood sugar levels.
Researchers have found a number of dietary items that produce this desired effect and green tea is one of the most promising.
The aim of a study published in the Iranian Journal of Medical Sciences was to compare the effect of sour and green tea consumption on insulin resistance.
Sour tea, also known as hibiscus tea, derives from the hibiscus plant native to India and Malaysia and green tea is made from the leaves of the Camellia sinesis plant.
For the study, 100 type 2 diabetes patients were randomly assigned into the sour tea group and green tea group.
The patients were instructed to drink 150ml sour tea and green tea infusion, respectively, three times a day for four weeks.
Fasting blood sugar – average blood sugar after an overnight fast, lipid profiles (blood fats such as cholesterol), insulin sensitivity and other important markers were monitored.
What did the researchers find out? HDL cholesterol levels significantly increased in both groups.
HDL cholesterol is branded the “good” cholesterol because it reduces your risk of heart disease by lowering “bad” cholesterol levels.
Crucially, the green tea intervention reduced insulin resistance more than the sour tea intervention.
Fasting blood sugar levels also underwent a “significant” reduction in the green tea treated group.
The researchers concluded: “This study shows that the use of 150 ml infusion of green tea or sour tea, three times a day for four weeks, has a positive effect on insulin resistance and certain lipoproteins in type 2 DM.”
Why green tea?
Teas such as black tea, green tea and oolong tea contain polyphenols which researchers believe may increase insulin activity.
An American study of 2002 found, however, that addition of milk in tea decreased the insulin-sensitising effects of tea.
Polyphenols are known to have anti-oxidative properties which can help protect against inflammation and carcinogens.
In other words, the properties in tea can help to prevent type 2 diabetes and mitigate its effects.
Diet is not the only effective means of moderating blood sugar levels.
Physical exercise also helps lower your blood sugar level.
“You should aim for 2.5 hours of activity a week,” advises the NHS.
Type 2 diabetes – do you have it?
Many people have type 2 diabetes without realising. This is because symptoms do not necessarily make you feel unwell.
Symptoms of type 2 diabetes include:
- Peeing more than usual, particularly at night
- Feeling thirsty all the time
- Feeling very tired
- Losing weight without trying to
- Itching around your penis or vagina, or repeatedly getting thrush
- Cuts or wounds taking longer to heal
- Blurred vision.