More than likely, you have heard the health claims about green tea. Perhaps you have seen products containing green tea extracts on store shelves and read the claims of antioxidant benefit. You may also have read reports that green tea makers are in hot water with the FDA for making "unsubstantiated nutrition claims."
With so many things flying around, it can be difficult to decipher fact from fiction. Here is some basic information we hope will help you decide where green tea fits in your healthy beverage options.
Some claims are general in nature such as that green tea prevents cancer, raises metabolism, or reduces cholesterol to benefit overall health. Other claims are more specific including that it stops Alzheimer's and Parkinson's diseases, treats rheumatoid arthritis, or treats impaired immune function. More and more claims are focusing on specific ailments such as that green tea helps burn fat for weight loss, cleanse the liver of toxins, assists with the prevention of type 1 diabetes, and fights a variety of cancers. Those with the risk of illness as well as those living with illness hope the claims are true. Those seeking to live health focused lives and reach weight loss goals want the claims to be true as well. But are they?
Tea made from the Camellia sinenesis plant can be in three varieties: green, black, and oolong. Although they all have the same origin, their differences come from processing. Green tea gets all the hype for the health benefits because of its unfermented leaves that have undergone the least amount of processing. Consumed throughout Asia for generations, green tea is used for a variety of health reasons in both traditional Chinese and Indian medicine. It is typically brewed and consumed as a beverage but extracts have become very popular in the United States.
Green tea contains polyphenols as bioflavoid and catechin compounds. Among those catechins, about half are epigallocatechin gallate (EGCG for short). EGCG have strong antioxidant properties, which are about 200 times more potent than vitamin E. It is this predominant active component in the leaves of green tea that are believed to block carcinogens and free radicals that can cause cancer. There is also indication that they may exhibit antibacterial benefits that protect the digestive and respiratory systems as well.
Some studies have shown promise with green tea related to cancer. In the laboratory, tea catechins inhibited cancer growth. Unfortunately, study results in humans have been contradictory. According to the U.S. National Library of Medicine, most of the health claims for green tea have "unclear scientific evidence" related to their claims. The caffeine can initially increase alertness in those that are not used to consuming caffeine. However, over time this response will diminish as the body adjusts to the caffeine.
A 2007 report by the United States Department of Agriculture (USDA) compared foods for catechin flavonoid content. They reported that no other beverage comes close to the catechin content in regular brewed green tea. They found that one hundred millimeters of green tea when brewed contains 126 mg of catechins while brewed oolong tea only contains 50 mg and brewed black tea only 28 mg. The report also revealed that regular green tea is the healthiest but the more processed tea becomes the more nutrients it loses. This includes the decaffeination process (56 mg) and flavoring process (43 mg), which reduces the catechin content significantly. If you are consuming instant or bottled green tea sources, most contain a disappointing 12 mg of catechins. Since Red wine contains 11 mg and unsweetened apple juice provides 6 mg, perhaps bottled or instant green tea isn't worth the cost or the hype it receives for the health benefit it offers.
Other food sources provide catechins although not as many as brewed green tea. Dark chocolate tops the list by providing 54 mg/100 grams if it is a pure Netherland source. Berries are your best nutrient rich, calorie wise option with blueberries offering 52 mg and blackberries 42 mg per 100 grams. If you love apples, be sure to eat the skin because it provides 36 mg of catechins.
There are a few other things to keep in mind when considering green tea. It contains a small amount of vitamin K, which can interfere with anticoagulants and make them less effective. Since green tea contains caffeine, it will also increase chances of insomnia, anxiety, irritability, upset stomach, nausea, diarrhea, or frequent urination in some people. Caution is indicated when taking concentrated green tea extracts especially if you have a liver disorder or experience abdominal pain after consumption.
What We Say
Green tea extract supplements are the fourth most common dietary supplement in the United States. Food is the best way to meet nutrient needs. Including a variety of food and beverage selections ensures you get everything necessary for good health. If you believe a supplement would be beneficial, it is best to seek advice from your medical provider, a pharmacist or consult a Registered Dietitian. They can help you decide about overall safety and recommend a dosage that would be beneficial as well as safe.
Brewed green tea can have a place in a healthy diet along with other coffee or tea choices. If you are looking for the greatest antioxidant health benefit, regular caffeinated brewed green tea is the form that will provide it. As with all things, moderation is important. If caffeine is a concern, remember there are other healthy foods like berries and apples with skins that provide similar antioxidant health benefits as well.
Be leery of food labeling for green tea extracts on food and beverage packages. Remember the buzz words are meant to catch your attention so that you'll buy their product and are not based on specific scientific results.
Did you know the facts about green tea or were you caught up in the marketing hype? Where does green tea fit in your healthy diet?
More From SparkPeople