Chilling temperatures, stark landscapes, and long, dark nights inspire the desire to curl up with a nice hot cup of tea. Unlike coffee, which we tend to gulp more quickly, tea is all about peaceful enjoyment, sipped slowly as the tendrils of steam curl fragrantly around the nose. Nourishment and wellness are enduring legacies of the vast empire of tea, as research points out. No wonder that Americans serve more than 50 billion cups of tea annually, and a driving factor in tea consumption is the desire to enjoy its health benefits.
A Tale of Teas
The tea world can basically be divided in half: camellia and herbal. Camellia sinensis leaves are used for a variety of types of tea: black, oolong, green, and white. The differences between each involve various degrees of oxidation and how the tea leaves are processed.
Black tea leaves are oxidized up to four hours, while oolong oxidizes for two to three hours. During oxidation, camellia leaves evolve chemically, resulting in characteristic color and flavor changes.
Green and white teas, by contrast, are not oxidized at all but are steamed, rolled, and dried. Green tea comes from mature leaves, while white tea results from immature leaves harvested prior to their opening fully, when the buds feature a fine, white, hair-like substance. All these teas are rich in flavonols (plant-based antioxidants) like quercetin, kaempferol, and myricitin.
Herbal teas contain no Camellia sinensis. Instead they are flavorful infusions of botanical roots, bark, leaves, seeds, and other plant parts. Technically, an herbal tea is known as a tisane. Additionally, rooibos, or red tea, constitutes its own province in this realm.
Black Tea and Your Health
Due to oxidation, black tea has a stronger, more bitter taste than green or other teas. Several studies suggest that drinking between three to five cups of this tea daily may support heart health. One study shows that individuals who consume more than 16 fluid ounces of black tea daily have a 50 percent lower prevalence of cardiovascular disease than those who don’t drink tea.
More evidence for black tea consumption and heart health comes from a study indicating that people who consume more than three cups of black tea a day can reduce their risk of having a heart attack by 43 percent, compared to those who don’t drink tea. Drinking black tea may also boost heart health by improving cholesterol levels. A U.S. Department of Agriculture trial found that those who drink five cups of black tea daily, while consuming a diet moderately low in fats and cholesterol, had a decrease in LDL cholesterol of 11 percent in only three weeks.
In addition, enjoying black tea seems to improve skeletal mass in older women. One study assessed bone mineral density (BMD) in tea drinkers and non-tea drinkers to find that tea drinkers had an average of 5 percent greater BMD than non-tea drinkers. Study authors suggest that tea’s flavonoids may influence BMD.
Black tea may even assist the body in recovery from stress. Men who drank tea four times a day for six weeks had lower levels of the stress hormone cortisol in their blood after a stressful event, compared to the control group that did not drink tea.
Green is Good
Perhaps the most notable tea for health is green; it has a stellar reputation, and many reports cite it for overall good health, possible cancer prevention, and other benefits. Its health-promoting properties are ascribed to the superior level of active catechins due to the leaves’ unfermented state. One active green tea substance in particular, epigallocatechin-3-gallate (EGCG), seems to prevent changes in cells that can lead to chronic disease. Green tea may even promote weight loss. Scientists have shown that it can increase metabolic rate.