Today we had a guest lecturer: John Kokko from the Turtle Island Health Clinic, who came to talk to us about the benefits of tea in scientific terms.
For notekeeping purposes, the following is taken from the copy that John Kokko gave us and my scribbling of what he says:
Main constituents in white, green and oolong tea:
1. Caffeine (most in red/black teas)
2. Theanine (most in white, green, green pu’er) – only tea has this substance
3. Antioxidants (polyphenols, catechins, especially EGCg) (most in white and green)
In red and pu’er teas, there are more tannins but less antioxidant than in the unoxidized teas. Matcha tea has over 3 times the antioxidant content of any other green tea.
Caffeine content per 8 oz cup:
– Green tea: 6-30 mg/cup
– Oolong: 10-45 mg/cup
– Red/black tea: 20-90 mg/cup
– Brewed coffee: 60-160 mg/cup
Usually people need about 300 mg/day (to stay alert?), which is equivalent to 3 cups of red tea. About 30% of American people need 600 mg of caffeine per day. Caffeine has a half life of 6 hours, that’s why drinking tea and coffee in the evening keeps some people from falling asleep. Personally, I can sleep anytime, tea or not, and I don’t drink coffee.
Tea and coffee also dehydrate the body. For every cup of tea, you need 2 cups of water to stay hydrated. For every cup of coffee, you need 4 cups of waters. This also means drinking tea or coffee can make you lose water weight, so people get thinner when they drink too much tea without replenishing with water.
Interesting number: you need 200 cups of tea in one sitting to be overdosed on tea.
Health benefits of tea:
Green tea is the most healthy tea, and among the green teas, Dragon Well (Longjing tea) has the highest amount of theanine, and it is the sweetest tea. But it is hard to get now because of pollution in Hangzhou. Oolong is in the middle range in health benefits: 1 cup of green tea is as healthy as 2 cups of oolong.
- Calm the mind, reduces stress: unlike caffeine which puts your brain in the beta state (alert state), theanine stimulates the alpha brain waves (meditation state)
- Regulate neurotransmitter activity in the brain (GABA, dopamine, serotonin)
- Strengthen immunity with antioxidants, especially EGCg. Tea is over 100 times more effective in neutralizing free radicals than vitamin C and 25 times more effective than vitamin E.
- Reduce the levels of LDL (bad cholesterol), reduce the oxidation of cholesterol and decrease lipid deposits associated with heart diseases
- Studies show a 65% decrease risk of hypertension for those who drink at least 2.5 cups of tea per day, and up to 70% decrease risk of stroke when drinking up to 9 cups/day because tea inhibits the formation of blood clots.
- Help with natural weight loss: 1. up to 10% more fat-burning by increasing fat oxidation and metabolic rate; 2. dissolving triglycerides, which are made of mainly sugar and fat; 3. influencing amylase, an enzyme that breaks down carbohydrates; 4. regulating the insulin levels so that more fat is burnt than stored
- Reduce inflammation in joints and protect cartilage destruction, due to the EGCg
- Reduce allergies by blocking production of histamine and IgE (is this why Asians rarely use “allergy” as an excuse, while Caucasian Americans are constantly troubled by pollen, shrimp, sesame, and a miriad of other things?)
- Reduce wrinkle and acne by decreasing the activity of collagenase, an enzyme that breaks down collagen
- Helps fending off infections by boosting the effectiveness of antibiotics
- Prevent gingivitis and periodontal disease by killing E. coli and streptococcus bacteria
- Reduce radiation damage to cells in the mitochondria
- Slow down the onset of Alzheimer’s and Parkinson’s diseases by protecting the brain from oxidative damage
The heating and cooling effects of tea:
The concept of “hot” and “cool” food is foreign to Westerners but common in Asia. My mom always says “don’t eat that, it’s hot” or “eat that, it’s cool”. Shrimp is hot, salt water fish is usually hot, fresh water fish is cool, eel is cool, mango is hot, chicken is hot, pork is cool, beef is hot, chocolate is hot, orange is cool, most vegetables are cool. Ginseng is hot. You get the pattern. A food is hot when it boosts your energy, gives you acne, gives you a sore throat, etc. Too much of hot food makes you sick, but I haven’t heard of “too much cool food”. To put it in Chinese terms, it is yin vs. yang.
Coffee is undoubtedly hot. From her tea drinking days, Mom claimed that tea is hot, so I asked John Kokko. As I expected, the lighter tea is cooler than the darker ones. The hotness rises with the oxidation level and differs by the method of drying the leaves: steam-dried tea (Japanese green teas) is the coolest, and wok-dried tea would be hotter than sun-dried tea (white teas). Oolongs are neutral. Red/black tea is hot. Mom must have drunk some really attractive red tea. 😉