Coffee and tea. Are they healthy for you? What scientific research has been done? Which brands or varieties are most desirable?
Over 50% of adults in the United States drink at least one cup of coffee or tea per day. Should they continue?
Health Benefits of Coffee
There is strong evidence that drinking 2–4 cups of regular, unsweetened coffee per day provides health benefits for some people. (See list of who should avoid coffee below.)
“Evidence has been pretty convincing that coffee has been more healthful than harmful in terms of health outcomes,” said Frank Hu, chair of the Department of Nutrition at Harvard T.H. Chan School of Public Health. “For most people, moderate coffee consumption can be incorporated into a healthy diet.”
Moderate coffee drinking is linked to a lower likelihood of type 2 diabetes, heart disease, liver and endometrial cancers, Parkinson’s disease, and depression.
Early research linked coffee to diseases ranging from heart disease and asthma. However, many participants in those studies also smoked, which led researchers to think that coffee was responsible for the adverse effects that are now linked with cigarettes.
Why is Coffee Healthy?
Roasted coffee is a complex mixture of over 1000 bioactive compounds, some with potentially therapeutic antioxidant, anti-inflammatory, antifibrotic, or anticancer effects. Studies have suggested that some of the same reductions in diabetes and heart disease risk are associated with decaffeinated coffee, which means it’s not just the caffeine.
Coffee is also an appetite suppressant. Eating less than the average American diet has health benefits, although make sure not to starve yourself.
Which Variety of Coffee is Healthiest?
There is no research-backed conclusion as to which kind of coffee is healthiest. However, avoid very dark roasts (because of low antioxidant content), very light roasts (because of high caffeine content), sweetened lattes and unfiltered coffee. Unfiltered coffee is associated with higher rates of early death, and can contain compounds that raise levels of LDL, or “bad,” cholesterol. Examples of types of unfiltered coffee include espresso, french press and boiled Turkish coffee.
Unsweetened medium-roast black coffee is probably the best. Do not rationalize your coffee drinking as healthy if you are adding cream, sugar or artificial sweeteners.
Health Benefits of Tea
Drinking tea has been considered a health-promoting habit since 3200 BC. Every day around the world, 3 billion cups of tea are consumed! Black tea is the most popular, perhaps because it contains the most caffeine.
Scientific studies are proving the health benefits of tea. Green tea has cancer-preventive effects. Black tea may have similar beneficial effects. Various studies suggest that green and black tea are associated with prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease. Tea consumption also has inflammation reduction, anti-aging, antidiabetic and immune system beneficial effects.
Why is tea healthy? Evidence is accumulating that catechins and theaflavins, the antioxidants in green and black tea, respectively, are responsible for most of the health benefits from tea.
Which Variety of Tea is Best for You?
There are over 1000 varieties of tea. Which teas are best for you?
To find out, see this excellent article from The University of Penn Medical School on the different types of caffeinated and herbal teas along with their health benefits.
Health Risks of Caffeinated Coffee and Tea
Daily total caffeine intake should be limited to 1.4 mg per pound of body weight. For a 150 lb person, this would be 210 mg / day.
One 8 fluid ounce cup of coffee contains about 95mg of caffeine.
One similar cup of black tea contains 47-90 mg of caffeine, green tea from 30-50 mg and white tea 15-39 mg. White, green, oolong and black teas undergo differing degrees of oxidation, with black tea being the most oxidized. Green tea and white tea are not oxidized, while oolong tea is partially oxidized. Oxidation, which occurs when the tea leaves are crushed and mashed together, produces a higher caffeine content.
Within one hour, caffeine reaches its peak level in your blood. Effects continue for four to six hours.
Caffeine impacts your metabolism by:
- Stimulating your central nervous system to make you feel more awake and give you a boost of energy
- Acting as a diuretic to remove extra salt and water by urinating more
- Increasing stomach acid, potentially causing an upset stomach or heartburn
- Impeding the absorption of calcium, leading to a 5% higher risk of fracture, especially in women
- Increasing blood pressure
The negative effects of too much caffeine include restlessness and shakiness, insomnia, headaches, dizziness, rapid heartbeat, dehydration and anxiety. Also, caffeine usage is mildly addictive and you may become dependent. The effects of caffeine lessen with frequent usage leading to taking more to get the same results. Avoid this behavior. Also, avoid caffeine consumption within six hours of bedtime. Sleeping well is the #1 factor for your health.
Who Should Avoid Caffeinated Coffee and Tea?
According to the National Library of Medicine, coffee, tea and other caffeinated beverages should be avoided if you:
- Are pregnant or breastfeeding, since caffeine passes through the placenta to your baby.
- Suffer from sleep disorders, including insomnia.
- Get migraines or other chronic headaches.
- Have anxiety, GERD or ulcers.
- Have arrhythmia (a problem with the rate or rhythm of your heartbeat) or high blood pressure.
- Take certain medicines or supplements, including stimulants, certain antibiotics, asthma medicines, and heart medicines. Check with your health care provider about whether there might be interactions between caffeine and any medicines and supplements that you take.
- Are a child or teen. Neither should have as much caffeine as adults. Children can be especially sensitive to the effects of caffeine.
Additional Health Risks of Tea
In an awful origin myth about tea, a Tang dynasty era legend, Bodhidharma, the founder of Chan Buddhism, accidentally fell asleep after meditating in front of a wall for nine years. He woke up in such disgust at his weakness that he cut off his eyelids. They fell to the ground and took root, growing into tea bushes. Hopefully the readers of Keep Health are wise enough not to do this!
Other than cutting off your eyelids, also avoid drinking:
- Fad detox teas for losing weight which contain laxatives
- Sugar-laden tea lattes, bubble teas and other sweetened tea beverages
- Herbal teas with ingredients which trigger your allergies
Coffee and Tea Health Benefits Conclusion
At the end of each Keep Health article, we recommend rewarding yourself for taking time to focus on your health. For coffee lovers, read up on the history of coffee. Did you know it likely originated in Yemen? For tea lovers, the next time you are in Boston, take a trip to the Tea Party Museum and throw some tea into the harbor. If you don’t like coffee or tea, then go enjoy your favorite healthy beverage instead.