Green Tea and 2010

Green Tea and Your New Year Resolutions

By Gigi Chow N.D.

That time of the year is coming again. It’s time to think about some resolutions to ring in 2010! Green tea may help you stick to and follow through the changes that you want to make for the coming New Year.

WeightLoss

Over 67 percent of adult Americans, that is approximately 2 out of every 3 Americans, is considered overweight or obese according to the CDC (1), so it is not surprising to find that weight loss is one of the most popular New Year's resolutions. How will green tea help you achieve your weight loss goals?

Reports (2) have shown that green tea extract intake is associated with increased weight loss. Thanks to the ever famous antioxidant associated with green tea, EGCG (epigallocatechin gallate) along with caffeine, green tea can increase thermogenesis or the rate at which calories are burned, and therefore boosts metabolism. Raising metabolism causes the body to burn more calories, which in turn can lead to weight loss.

In addition, research (3) indicates that green tea consumption activates a higher rate of fat oxidation, or the rate at which fat is burned. In a human study, participants taking green tea extract experienced a significant increase in their energy expenditure compared to pure caffeine, ephedrine, and capsacin (a compound found in cayenne peppers). The researchers concluded that participants using green tea extract had increased fat oxidation beyond what could be attributed to the caffeine they consumed from the green tea. This indicates that green tea contains beneficial components that affect the body's metabolism in such a way that favors weight loss.

Green tea also shows promise in appetite suppression. Scientists at the University of Chicago's Tang Center for Herbal Medicine Research have found that a major chemical component of green tea caused rats to lose up to 21 percent of their body weight (4). Rats injected with EGCG derived from green tea leaves lost their appetites and consumed up to 60 percent less food after seven days of daily injections.

While many over-the-counter diet aids are stimulants and therefore raise heart rate and blood pressure, participants using green tea extract did not have increased heart rate, suggesting that green tea may be an alternative to many stimulant based diet aids.

Greater Heart Health

Too much fat in the blood is definitely bad for the heart. This is because the when excessive levels of fat accumulate in the blood vessels and become oxidized (oxidation is a normal cellular process), the oxidation of fat long term may cause damage to the vessels. Damage to the vessels lead to inflammation and may lead to the deposition of additional fats to the site of damage. Over time, this process leads to decrease circulation to the heart, elevated high blood pressure and heart rate, and eventually a heart attack. Green tea extract has been shown to lower cholesterol and thus may play a beneficial role in heart disease prevention.

A study done on August 2009 (5) investigated the effects of green tea extract and individuals with high blood lipids (cholesterol and triglycerides). The study included 33 subjects aged between 21 and 71 years who had a low-fat diet (25-35% of total calories and 200 mg of cholesterol per day). They were randomized for two sequential treatments: 250-mg capsules of green tea dry extract or placebo for a total period of 16 weeks; each patient received green tea (Camellia sinensis) for eight weeks and placebo for another eight weeks.

The results at the end of the 16 weeks revealed that in the eight weeks that participants received green tea extract, there was a significant reduction of total cholesterol and LDL-cholesterol levels

Green tea extract may also help lower blood pressure and inflammation. Inflammation is a process that is not only involved in heart disease but many chronic degenerative conditions such as multiple sclerosis and arthritis. A randomized, double-blind, placebo-controlled, parallel study on 111 healthy adult volunteers 21-70 y old was performed (6). Green tea extract was effective for decreasing, in as quickly as 3 weeks, blood pressure, LDL cholesterol, and a marker of chronic inflammation, all independent cardiovascular risk factors.

Green tea extract therefore shows considerable promise in prevention of cardiovascular diseases.

Stress Reduction

Is stress getting the best of you? If your goal is managing your stress better, green tea can help.

According to a very recent study (7), the study involved over 40,000 Japanese individuals and found an inverse relationship between psychological stress and green tea consumption. In other words, the more green tea consumed, the less the psychological stress.

L-Theanine is an amino acid contained in green tea leaves and is responsible for green tea’s relaxation effect. The calming effect of green tea may appear contradictory since you may think that the caffeine in green tea would stimulate. However, the action of L-Theanine actually acts antagonistically against the stimulatory effects of caffeine on the nervous system (8). First, L-Theanine directly stimulates the production of alpha brain waves, creating a state of deep relaxation and mental alertness similar to what is achieved through meditation. Alpha is present in wakefulness where there is a relaxed and effortless alertness (9). Second, L-theanine is involved in the formation of the inhibitory neurotransmitter, gamma amino butyric acid (GABA). GABA influences the levels of two other neurotransmitters, dopamine and serotonin, producing the key relaxation effect (10).

Stress and anxiety are debilitating conditions that can lead to a loss of our well-being, performance, and even lifespan. Stress also impairs the immune system, leaving us vulnerable to infections, and can cause depression. Stress and depression are intimately connected and they increasingly take a toll on the health of the people around the world. The World Health Organization (WHO) forecasts that within 20 years more people will be affected by depression than any other health problem; it ranks depression as the leading cause of disability worldwide, with around 120 million people affected.

Stress is undoubtedly and unfortunately a part of daily living. Consumption of 50 mg of L-theanine (equivalent to two-three cups of tea) stimulates the alpha-brain waves associated with relaxation. L-Theanine is also available as a dietary supplement. The simple addition of green tea or L-Theanine supplementation may help lessen the physical and psychological effects of acute and chronic stress.

Side Effects

Tea is the most consumed beverage worldwide after water, and has been consumed for thousands of years by billions of people. Green tea consumption is therefore generally safe. However, individuals with certain conditions should check with their doctors before consuming high quantities of green tea.

Green tea, although it has the counterbalancing effect from L-Theanine, contains caffeine. Individuals sensitive to caffeine should keep all caffeine containing foods and beverages to a minimum.

The safety of tea extracts or supplements for pregnant or breastfeeding women has not been established. Some organizations advise pregnant women to limit their caffeine consumption to 300 mg/day, because higher caffeine intakes have been associated with increased risk of miscarriage and low birth weight in some epidemiological studies.

A number of drugs can impair the metabolism of caffeine, increasing the potential for adverse effects from caffeine (11). Such drugs include cimetidine (Tagamet), disulfiram (Antabuse), estrogens, fluoroquinolone antibiotics (e.g., ciprofloxacin, enoxacin, norfloxacin), fluconazole (Diflucan), fluvoxamine (Luvox), mexiletine (Mexitil), riluzol (Rilutek), terbinafine (Lamisil), and verapamil (Calan). High caffeine intakes may increase the risk of toxicity of some drugs, including albuterol (Alupent), clozapine (Clozaril), ephedrine, epinephrine, monoamine oxidase inhibitors, phenylpropanolamine, and theophylline. Abrupt caffeine withdrawal has been found to increase serum lithium levels in people taking lithium, potentially increasing the risk of lithium toxicity. It is therefore recommended to take green tea away from all medications.

Excessive green tea consumption may decrease the therapeutic effects of the anticoagulant, warfarin or Coumadin (11). Such an effect was documented in one patient who began drinking one-half gallon to one gallon of green tea daily. It is probably not necessary for people on warfarin therapy to avoid green tea entirely; however, large quantities of green tea may decrease its effectiveness.

Flavonoids in tea can bind non-heme iron, inhibiting its intestinal absorption (11). Non-heme iron is the principal form of iron in plant foods, dairy products, and iron supplements. The consumption of one cup of tea with a meal has been found to decrease the absorption of non-heme iron in that meal by about 70%. To maximize iron absorption from a meal or iron supplements, tea should not be consumed at the same time.

Summary

If your New Year goals involve losing weight, lowering blood pressure and cholesterol, and managing stress and calming anxiety, green tea will definitely give you a helping hand in achieving your resolutions. Have a happy and healthy 2010!