It has been well established already that antioxidant-rich green tea, for instance, protects your heart and helps prevents certain cancers and Alzheimer’s disease. Some research has also shown that green tea can lower high blood pressure and keep insulin in check — two big factors involved in the development of metabolic syndrome.
In a study, researchers from Penn State examined the relationship between tea consumption — specifically green, black and oolong tea, both hot and iced — and multiple markers for metabolic syndrome. The markers they looked at included body mass index (BMI), waist circumference, fasting glucose, cholesterol (total, HDL, LDL and triglycerides), and C-reactive protein.
A total of 6,427 adults participated in this study. They were divided into one of four categories of consumption of both hot and iced green, black, and oolong teas, based on their answers in food frequency questionnaires:
- Non-consumers (rarely or never drink tea)
- Weekly consumers (2 to 6 cups per week)
- Daily consumers (1 cup per day)
- Multiple cups per day
Next, their weight status was assessed using BMI, and their body fat was evaluated using waist circumference, as well as tricep and subscapular skinfold thickness. Researchers also collected fasting and non-fasting blood samples.
The results of this study showed that regular tea consumption was associated with decreased weight.
Specifically, women in the highest category of hot tea consumption (multiple cups per day) had the lowest BMI (26.2 versus 28.5 for non-consumers). A similar relationship was found in men (25.4 versus 27.9 for non-consumers). Both men and women who drank multiple cups of hot tea a day also had a smaller waist circumference, but a stronger association was found among the men.
Interestingly, drinking iced tea had the opposite effect. Women saw a significant increase in waist circumference, skinfold thickness and BMI. Among men, non-consumers had significantly lower BMI and waist circumference than men who drank multiple daily cups of iced tea. Also, subscapular skinfold thickness increased in both men and women who drank iced tea.
Other observations included:
Fasting Glucose: Hot tea consumption was inversely related to fasting glucose in women only. There was no effect on fasting glucose in men or women who consumed iced tea.
Blood Lipids: Researchers found no correlation between HDL cholesterol, LDL cholesterol, and triglycerides and hot tea consumption in women. But there was a significant decrease in HDL (“good”) levels and triglycerides in women as their iced tea consumption increased.
Men who consumed multiple cups of hot tea every day had significantly higher HDL levels and lower triglycerides than the non-consumers. They found no significant observations in lipids in men who drank iced tea.
C-Reactive Protein: The researchers discovered lower C-reactive protein in both men and women who drank hot tea. However, there was no association between iced tea consumption and C-reactive protein in men and women. These results indicate that hot tea consumption may reduce the risk of cardiovascular events.
Drink It Hot
What is it about hot tea that appears to make it a better option in reducing metabolic syndrome markers, especially weight and body fat? Researchers believe it’s because hot tea has higher antioxidant content, and often contains lower amounts of sugar, too.
In addition, adults who regularly consume hot tea also have higher caffeine intake, and studies have shown that caffeine can boost your metabolism and energy expenditure, helping you lose additional pounds. Finally, researchers state that the positive weight loss results could simply be due to the fact that tea contains high amounts of antioxidant polyphenols, which can help boost weight loss.
While the effects of hot and iced tea on blood lipids was mixed, it does appear that drinking hot tea can reduce inflammation in the body and cardiovascular risk, as measured by the marker C-reactive protein. But the greatest effects seem to be with weight and body fat reduction.
So if you want to boost your weight loss efforts and prevent metabolic syndrome in the process, drinking hot green, black or oolong tea might be a good option for you. Just be sure to enjoy your tea without sugar.
If you must add a little sweetness to your beverage, try an all-natural sugar substitute like stevia or xylitol. Unlike sugar, both of these sweeteners do not mess with your glucose levels, making them excellent options if you have diabetes.
 Vernarelli JA and Lambert JD. Tea consumption is inversely associated with weight status and other markers for metabolic syndrome in US adults. Eur J Nutr. 2012 Jul 10. [Epub ahead of print.]