There are few things more comforting than taking a little time to relax and enjoy a cuppa. But, scientists have now found that tea does more than just taste good - certain properties in some types of this brew could help aid weight loss as well.
The various health benefits of tea have previously been shown to reduce the risk of cardiovascular disease and type 2 diabetes, and also reduce the risk of developing pre-diabetes.
However, this recent research, conducted by scientists at the Hunan Agricultural University in China, analysed studies into the efficacy of tea components, concluding that there are “functional components of tea leaves in fat reduction and energy metabolism in weight loss”.
The study, published in the Journal of Nutritional Biochemistry earlier this year, noted that “a large number of basic studies have demonstrated that the main functional components and extracts of tea have positive lipid-lowering and weight-loss effects”.
Different types of teas were seen to have different benefits. One early clinical study found that drinking 8g of oolong tea per day for six weeks “reduced body weight, plasma TG and total cholesterol levels in obese individuals”.
Meanwhile, polyphenols present in green tea were seen to have a positive effect on reducing blood glucose concentration in adult men when drunk in the evening.
Read more: Health benefits of tea as one cup a day could cut risk of diabetes by a quarter (Yahoo Life UK, 3-min read)
How can tea help with weight loss?
There are several key ways in which tea components may be able to help people lose weight, the study outlined.
1. Regulating fat production and metabolism
The researchers said that their review showed that functional components in tea can also help restore “normal metabolic function of obese patients” and “prevent/inhibit the development of obesity”.
Catechins, which are the dominant polyphenols in green tea, are also said to increase fat burning during exercise and rest. A study showed that men who took green tea extract before working out burned 17% more fat compared to men who did not take it.
2. Regulating blood glucose
“Tea and its main functional components have been widely reported to exert a positive regulatory effect on human glucose metabolism,” the researchers said. “This effective method may be an important way for the functional components of tea to reduce lipids and lose weight.”
Studies showed that black tea extract had the biggest effect on blood glucose. Scientists suggested that the functional ingredients of tea could “reduce the excessive accumulation of blood sugar in the body by regulating the activity of digestive amylase secreted by digestive organs such as the pancreas”.
Read more: 20 things you didn’t know about tea drinking (Yahoo Life UK, 5-min read)
3. Improve liver function
The liver plays a major role in the body, by assisting with metabolism, preventing the accumulation of drugs and toxins, oxidising fat and allocating excess fat to be secreted and stored in other tissues.
The study found that polyphenols and other components of tea can be metabolised through the liver “into small-molecule compounds that are more likely to be absorbed and used by the human body”. This means that the regulatory effect of tea on liver metabolic function can help “prevent obesity and obesity-related diseases”.
Tea, specifically madai tea extract, was also found to regulate “anti-oxidation and anti-inflammatory pathways”, therefore reducing liver steatosis (a harmless build-up of fat in liver cells) and liver inflammation.
“Moderate intake of the functional components of tea showed positive effects on liver fat metabolism, chronic liver inflammation, and oxidative stress,” researchers wrote.
The top 5 types of teas that aid weight loss, according to the study:
1. Green tea: Shown to promote fat-burning
2. Oolong tea: Improves metabolism
3. Black tea: Reduces calorie intake
4. Fermented tea: Helps control blood sugar levels
5. White tea: Boosts fat-burning
But, is it healthy to drink too much tea?
Drinking two or more cups of tea per day is linked with a lower risk of death, compared with not drinking tea, according to a study published in the Annals of Internal Medicine.
However, the British Heart Foundation said: "Although this research suggests that drinking tea is linked with a lower risk of death, even when sugar is added, it is still important to think about limiting how much sugar you have in general.
"Having too much sugar can lead to putting on excess weight, which is linked with an increased risk of coronary heart disease, strokes and developing type 2 diabetes. Before assuming that adding sugar to your tea is fine for your health, take stock of your sugar intake across your entire diet and make sure it is in line with recommendations from the NHS."