Focus on Arts and Ecology

For centuries, people have touted the health benefits of drinking tea. But what exactly can tea do for you?

1. Caffeinated hot tea may lower risk for glaucoma: A study published in the journal BMJ showed that caffeinated hot tea drinkers had a 74% less risk of developing glaucoma compared to people who drank decaffeinated tea, caffeinated coffee, decaffeinated coffee, or soft drinks. However, researchers couldn't determine why hot tea containing caffeine was beneficial in reducing the risk of glaucoma compared to other drinks.

2. Black tea may lower blood pressure: A study published in the American Journal of Clinical Nutrition showed that drinking three cups of black tea a day may lower blood pressure levels a few points. The study had a group drink black tea for six months and another group drink a similar caffeine drink for six months. The conclusion was that other properties of black tea helped lower blood pressure and not the caffeine.

3. Green tea has cancer-fighting properties — but be careful on the temperature: A catechin called EGCG found in green tea has been linked in various studies to a reduction in cancer rates. It may help in the reduction of the following types of cancer: bladder colon, esophagus, pancreas, rectum and stomach. However, a more recent study shows that you should be careful about the temperature of your tea. If you smoke or drink alcohol, let your tea cool first. A study published in Annals of Internal Medicine found that drinking tea while it's "hot" or "burning hot" was linked to an increased risk of esophageal cancer in people who also smoked or drank alcohol every day. And what defines too hot? In 2019, researchers answered that question, too, saying liquid hotter than 140 degrees Fahrenheit (60 degrees C) was the tipping point for risk, assuming they drank more than 2 large cups of tea a day.

Drinking green tea can may lower the risk of blood clots, stroke and heart disease. (Photo: panna-yulka/Shutterstock)

4. Green tea consumption linked to lower risk of coronary artery disease: In a study published in the official journal of the Japanese Circulation Society, researchers found that the more green tea you drink, the less chance you will have of developing coronary artery disease.

5. Green tea may reduce the risk of blood clots and strokes: "Green tea also lowers fibrinogen, which is a substance in the body that can cause clots and strokes," according to "150 Healthiest Foods on the Planet" by Jonny Bowden, Ph.D.

6. Green, black or oolong tea may improve brain health. A 2019 study published in the journal Aging found that regular tea drinkers have better organized regions in the brains than people who don't drink tea. These organized areas are associated with healthy cognitive function. Researchers found that people who drank green, oolong or black tea at least four times a week for about 25 years were protected against age-related cognitive decline.

7. Black tea may help soothe away the stresses of life: A study by University College London researchers found that those who drank a cup of black tea where able to de-stress faster when compared to those drinking a placebo.

Green tea is thought to lower the risk of some cancers. (Photo: Sea Wave/Shutterstock)

8. Drinking green tea results in a modest reduction in breast cancer risk. Researchers looked roughly 7,000 women aged 20-74 in a case-control study conducted in Shanghai from 1996-2005 and found a modest reduction in risk.

9. Rooibos (a caffeine-free, herbal tea) may reduce and treat metabolic diseases.

10. Rooibos and honeybush teas may help with skin cancer: In one study, rooibos and honeybush extracts suppressed skin cancers in mice, giving hope for a future in human studies.

11. Rooibos may be anti-aging: Or, at least a study done with quail and published in British Poultry Science found that it helped their egg production capabilities last longer. Since birds are a proposed animal for anti-aging studies, this holds hope that rooibos may help humans as well.

12. White tea was found to be more protective against oxidative stress when compared to green tea.

13. Rooibos tea (both red and green) were shown to have the highest protection for male fertility against oxidative stress: In a study that tested the oxidative stress reducing properties of supplements made from green tea, red rooibos, green rooibos, or Chinese green tea, rooibos extracts helped protect sperm health the most.

Drinking a variety of teas has been proven to be part of a healthy lifestyle. The sampling of studies above are just a drop in the bucket of a whole sea of research, which makes my tea-loving self feel very good.

Editor's note: This story has been updated with new information since it was originally published in January 2012.