When not otherwise specified, ‘tea’ usually refers to the plant camellia sinensis, which can be used to make black, green, oolong, or white tea (depending on the processing of the leaves).
Popular in China for thousands of years, tea only reached the Western world after the period of Portuguese exploration in the 16th century. Today, it’s far and away the most popular beverage worldwide, followed by coffee. (It’s interesting to me that the most popular beverages are all acquired tastes!)
There’s a good reason to acquire this one, though. In particular, tea (especially green tea) can be a great aid to cardiovascular health, blood sugar regulation, and weight loss.
The difference between green and black tea is the level of oxidation—green tea still contains many of the antioxidants that are no longer present in black tea. For this reason, by definition, green tea is much higher in antioxidant concentration. These include various flavonoids, particularly catechins (and especially EGCG, the well-known zinc ionophore). Some of these are lost with hot brewing, but they are completely preserved in cold brewed green tea.
Unfortunately, a large percentage of tea drinkers take theirs with milk. This study suggests that milk will block antioxidant absorption.
So it appears to be better to cultivate a taste for tea without the milk.
Tea for Cardiovascular Health
The flavonoids of green tea have been consistently shown to improve endothelial function and raise nitric oxide levels, very important for maintaining cardiovascular health. This study agrees that tea can improve endothelial function and vasodilation, leading to lower blood pressure.
Perhaps for this reason, this study shows that even those who drink less than one cup of green tea per day have a lower risk of cardiovascular disease and stroke, and the protection increases from there—those who drink more than four cups per day experience the greatest protection. This study agrees that three cups of either green or black tea daily may prevent a stroke.
Tea For Blood Sugar Control
There is a strong correlation between cardiovascular disease and elevated blood sugar—both are together part of the umbrella diagnosis of metabolic syndrome.
Tea for Weight Loss
While sometimes weight loss is as “easy” as decreasing sugar and white carbohydrate intake while increasing exercise, that’s unfortunately not always the case.
But for some, excess weight can be frustratingly stubborn. That’s the reason why trends like ozempic/semaglutide have caught on (though potential side effects for these can be severe, so I’m really not a fan).
Fortunately, cultivating a taste for tea might be a helpful weight loss aid (or if you hate the flavor, green tea comes in extracts too Here’s one of my favorite options for that).
This 12-week study using a green tea extract showed significant weight loss and reduced weight circumference, possibly because of lower ghrelin (the hunger hormone) and higher adiponectin.
This study shows that while catechins of green tea do indeed support weight loss, the effect has nothing to do with caffeine content. This study agrees: green tea seems to promote fat oxidation (breakdown) beyond what caffeine alone could account for. (So in other words, decaf is okay!)
There are always studies that disagree, though: this one says that while green tea does promote some weight loss, it wasn’t considered statistically significant.
Many of the studies show that various processing of camellia sinensis leaves still confer health benefits, though most seem to agree that green tea is the most beneficial. The optimal dose hasn’t been established, but even less than one cup per day still confers some benefits, while they seem to increase with greater intake, up to at least four cups per day.
It might especially behoove you to add green tea in to your routine if you have a personal or a family history of cardiovascular disease, blood sugar regulation issues, or you’re looking for an aid to weight loss. But it seems to be best to avoid adding milk to your tea, as it may block absorption of some of the tea’s most beneficial compounds.
(Tip: I don’t care for the flavor of green tea personally, but I love fruit teas, which are largely hibiscus-based. Try combining them! You can also consider green tea-based kombucha for the added benefits of fermentation, as well.)