The Real Health Benefits of Green Tea
When you hear the word “superfood,” you may picture colorful images of acai, quinoa, and kale. But what about a “superdrink”? If any such beverage exists, green tea certainly tops the list. Judging by the internet’s claims, green tea can do everything from magically clear cystic acne to make you “drop 14 pounds in 17 days.” More realistically, some studies have tentatively linked it to reduced cancer risk, better bone health, and improved cognitive function.
The green tea craze goes back a lot further than the age of the internet. As an integral part of Chinese medicine for thousands of years, this beverage has long been used to treat indigestion, anxiety, and low energy levels, among other ailments.
But information on green tea, even in scientific journals, often appears conflicting. Where one study seems to indicate it brings some decreased risk or increased protection, another may claim results aren’t clinically significant. All the back-and-forth leaves us wondering: If green tea really can offer health benefits, what are they? And how much would you actually have to drink to experience these benefits?
To find the answers, we spoke with Ali Webster, RD, PhD, Associate Director of Nutrition Communications with the International Food Information Council, whose doctoral research focused on the effects of green tea extract on body weight, body composition, glycemic control, and appetite-regulated hormones.
Webster explains that some of the confusion around green tea stems from the fact that a correlation with health benefits tends to be found when studies are observational, rather than randomized. This means that studies often look at people who already drink green tea, rather than adding it to the diet of those who don’t, making it a chicken-or-the-egg research proposition. “People who drink green tea may be more likely to engage in other healthy lifestyle habits that aren’t measured in very large, epidemiological studies,” she says.
So what are green tea’s proven benefits?
Whether or not subjects’ lifestyle already predisposes them to health, Webster emphasizes that research does reliably establish specific connections between green tea and positive outcomes. One example is reduced blood pressure. Scientists believe green tea’s catechins (AKA antioxidant compounds) may reduce inflammation and prevent fatty buildup, keeping too much pressure from pushing against blood vessels. This boon to your cardiovascular system allows your blood to properly reach its all-important destinations of your heart and brain — so you’re less likely to experience a heart attack or stroke.
Better blood sugar control is also among the green tea benefits Webster notes. A 2016 meta-analysis of 10 randomized studies showed that drinking green tea for over eight weeks helped stabilize fasting blood sugar and slightly reduced waist circumference in type 2 diabetics. Another (albeit self-reported) study concluded that these outcomes likely have to do with green tea’s caffeine content. While all this sounds like good news, Webster calls green tea’s positive effects on both blood pressure and blood sugar “statistically significant but still very small.”
let’s get down to the nitty gritty
If green tea can boost your cardiovascular health and reduce your blood sugar — even a little — how much does it take to actually experience these benefits? “In many studies that have shown statistically significant effects, participants have consumed about five cups of green tea a day,” says Webster. While drinking what amounts to an entire pitcher every day may not sound feasible to most Westerners, any quantity of green tea in the diet can be a healthy addition. Even one cup a day provides a dose of powerful antioxidants. These friendly compounds stop or delay cell damage by removing waste products, leaving your cells “cleaner” and better able to perform their intended functions. To extract the most from these compounds in green tea’s leaves, Webster recommends brewing and drinking it hot.
With its known antioxidant content and proven effect on blood sugar and blood pressure, it’s safe to say green tea is a healthy beverage choice — far better than many other options like soda or other sweetened beverages. Plus, with all the research around this superdrink, who knows what other benefits may await discovery?
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