Truth about impact of green tea on aging and metabolism

Green tea is gaining popularity as a health-conscious alternative to sugary beverages like sodas and energy drinks, according to a recent article. 

Could green tea be the new coffee? While coffee remains the most popular morning beverage in America, green tea is gaining ground. The green tea market is expected to grow significantly, potentially reaching over $28 billion in the US by 2030. This surge in popularity is largely attributed to green tea’s reputation as a healthful choice. But how does it compare to black tea or coffee in terms of health benefits?

All tea, except herbal infusions, originates from the Camellia sinensis plant. The differences in tea types come from their oxidation levels: white tea is made from unoxidized buds, oolong from partially oxidized leaves, black tea from fully oxidized leaves, and green tea from unoxidized leaves. Green tea is notable for having the highest levels of flavonoids, antioxidants known for reducing coronary inflammation. Despite its acclaim, some claims about green tea's health benefits are exaggerated.

For instance, green tea is linked to a reduced risk of certain cancers. Studies have shown that regular consumption might lower the risk of breast and lung cancer, though this benefit is often associated with overall plant-based diets, which are also linked to reduced cancer risks and chronic diseases like heart disease and diabetes. Even if you prefer coffee, incorporating more vegetables and fruits into your diet can provide similar protective benefits. Population studies suggest that frequent consumption of unsweetened green tea is associated with a lower risk of developing cardiovascular disease (CVD) and a reduced likelihood of dying from it. A 2023 review confirmed these links. However, these studies are often region-specific and may reflect genetic predispositions, particularly in places like Taiwan and Japan, where green tea is a staple. 

The benefit may also be attributed to green tea’s role as a healthier alternative to sugary drinks. Both domestic and international research consistently shows that drinking unsweetened tea, as opposed to sugary beverages, is linked to improved heart health and a decreased risk of other chronic diseases, particularly those related to obesity. Green tea is recognized for its potential to lower blood sugar levels, provided it’s consumed unsweetened. However, green tea is increasingly found in sugary products like juices, "tonics," frozen yogurt, and dressings. It’s important to check nutrition labels on packaged products to avoid excessive added sugars. Regarding caffeine content, not all green teas are caffeine-free, but they generally contain less caffeine than coffee. 

A standard cup of coffee has about 100 mg of caffeine, whereas green tea contains 25-50 mg, depending on the type and strength. For those sensitive to caffeine, choosing "caffeine-free" green tea or checking labels for 0 mg of caffeine can help. The USDA recommends consuming 300-400 mg of caffeine per day from coffee and tea to potentially enhance cognitive function and energy, so moderate consumption can be beneficial for those who tolerate caffeine well. Green tea is also known for its calming effects, partly due to its L-theanine content, which can improve focus and reduce anxiety. However, if you’re sensitive to caffeine, even green tea might not be as soothing. 

The idea that green tea alone can significantly boost metabolism or aid weight loss is overstated. Some small studies suggest a slight increase in metabolic rate with high caffeine consumption (about four cups per day), but the primary factor in increasing your basal metabolic rate (BMR) is building lean muscle mass through strength training. This is crucial for maintaining a healthy metabolism, as well as supporting overall bone, muscle, and immune function.