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Green tea extract makes it possible to reap the benefits of green tea without drinking six cups of brewed tea. With people all over touting their love of green tea, we look at the top six benefits that aren’t overhyped and are backed by solid scientific research.
Weight loss, cancer prevention, and lower risk of cardiovascular disease — green tea and its bioactive ingredients have been shown to promote a naturally healthy lifestyle. With so many scientific studies coming out about green tea and green tea extract, one hopes western healthcare would begin to utilize it more. (1)
Though the ancient Chinese did not have the scientific peer review system we have access to today, Asian tradition shows that green tea fosters heart health and holistic wellness. Some may put stock in the statistic that Americans are 50 percent more likely to develop cancer than the Japanese. (2)
This is likely due, in part, to the fact that diets in the United States are often filled with a lot of empty calories and not a lot of superfoods — or drinks, like green tea.
Known scientifically as Camellia Sinensis, green tea is typically consumed as a beverage. One cup of green tea is only one calorie! Green tea extract supplements can come in a few forms, and they possess several health benefits.
What is green tea extract?
Whenever you see “extract” (for example, vanilla extract), this can refer to one of three or four processes. A press can separate solids from liquids. Some raw materials are put through the process of maceration or distillation to produce an extract. Steeping tea leaves is even a form of extraction, called absorption.
Green tea extract comes in multiple forms: tablets, capsules, powders, and liquids. These pills or powders may simply be crushed green tea leaves.
Green tea extract is made up of 30 percent polyphenols, by weight. Polyphenols are the antioxidant rich compounds found in plants. The most important polyphenol in green tea is a catechin called epigallocatechin gallate (also known as EGCG).
EGCG and green tea extract have been tested in dozens of studies. Not only animal and in vitro trials have taken place, but human trials have been popping up for the past fifteen years. The consensus is that green tea extract’s two most bioactive ingredients are caffeine and EGCG. (3)
Top 6 Natural Health Benefits of Green Tea Extract — Backed by Science
With fewer side effects than most of what is approved by the drug administration, green tea extract is a safe method for reaping several benefits. High in antioxidants, green tea extract can help with fat loss, lowering cholesterol, promoting dental health, decreasing blood pressure, and even preventing cancer cells from reproducing.
There are multiple health benefits that go hand in hand with taking green tea extract. Some are backed up by randomized, controlled scientific studies, others have been tested once, and some in mice. Below, we’ll sort through the claimed benefits and find which are reliable and which are are yet to be fully researched.
Antioxidant: Fact vs. Fiction
Another name for green tea extract is green tea catechins. “Catechins” refers to the bioactive polyphenols that have been linked to many benefits, most notably increased antioxidants in the body.
Oxidative stress is the imbalance of antioxidants and free radicals. Long-term oxidative stress can damage cells and proteins in the body, including DNA. Oxidative stress can cause chronic inflammation leading to diabetes, arthritis, or heart disease. It may even lead to cancerous growths.
Though not a bad thing in the short-term, the body produces these free radicals as a byproduct of the normal metabolic process. But antioxidants are also produced naturally and antioxidants neutralize free radicals.
However, excess free radicals can occur under certain conditions, such as air pollution, radiation, a diet low on fruits and vegetables, and even exercise. Free radicals are molecules with at least one unpaired electron. When there aren’t enough antioxidants to neutralize the free radicals, oxidative stress occurs.
In a 2005 animal study, green tea extract is shown to reduce oxidative stress. This, in turn, may be useful in treating kidney disease, such as Cyclosporine A-induced kidney dysfunction caused by oxidative stress. (7)
Some studies rebuke antioxidant advantages though. A 2005 study found much of EGCG’s antioxidant effects had been trumped up. In this single study, researchers found EGCG had increased oxidative stress — though there are few studies to corroborate their findings. (8)
Oxygen radical absorbance capacity (ORAC) was the government-backed industry standard for antioxidant levels. An ORAC test used to show how well the heroes (antioxidants) stacked up against the villains (free radicals). But the US Department of Agriculture took down the ORAC database from its website.
“ORAC values are routinely misused by food and dietary supplement manufacturing companies to promote their products,” the USDA said. Manufacturers had been exaggerating their ORAC numbers with apple-orange comparisons.
But antioxidants continue to have great uses. If your diet is low in fruits and vegetables, or you exercise often, or you live a city high in pollution, consider upping antioxidant intake to avoid side effects.
As little as one cup of green tea a day or 50-100 mg of green tea extract (9)
Cancer Prevention: Reducing the Risk Factors
You might be thinking, “Cancer prevention? If green tea can prevent cancer, why doesn’t every doctor prescribe five cups a day?” Well, the science is still early but promising. Because of the rate of metabolism of green tea’s bioactive ingredients and limited understanding of the redox environment in vivo, it is difficult to apply things from a lab or animal studies to human trials.
Also, treatment of cancer seems much more pressing than prevention. But multiple studies, even human trials, have exhibited cancer preventative results. (10)
Even in the nineties, green tea was seen as a cancer preventative, particularly in Japan. One study showed that, among patients who drank at least ten cups of green tea a day, cancer onset was 3.0 years later among males and 8.7 years later among females. (11)
Prevention of oral cancer shows promise as well. Scientists suggest green tea extract may suppress oral premalignant lesions, partly by reducing angiogenesis. These studies have been observed in a lab, as well as in living organisms. (12, 13)
Green tea extract inhibited the growth of lung cancer and breast cancer in mice. And human studies into the effects of EGCG on human skin showed green tea extract may help prevent skin cancer as well. (14, 15)
Urokinase is a critical enzyme in cancer growth. An older study shows that green tea inhibits this enzyme — a possible explanation for green tea extract’s cancer preventing properties. (16)
In combination with the anti-inflammatory drug sundilac, green tea extract was shown to decrease tumors by half, in mice. The test group developed no adenocarcinomas during the trial, but one in ten mice in the control group did. But the researchers believed green tea’s catechin EGCG is most effective as a cancer preventative, rather than a cancer killer. (17)
On the flip side, green tea extract has been shown not to destroy tumor cells. In a study on 17 patients with advanced lung cancer, green tea extract had negligible effect on the malignant cells. Due to the “development of progressive disease”, the study did not go beyond 16 weeks. (18)
200 milligrams of green tea extract, up to three times a day.
Prolonged periods of daily doses more than 600 milligrams may eventually lead to some nausea. Do not exceed 800 milligrams.
Weight Loss: Oxidizing Fat
No matter our dreams of a magic pill, scientists have not come up with a better method for weight loss than diet and exercise. But green tea extract has been shown to aid in fat oxidation and thermogenesis, making it a good fat burner to improve your metabolic rate. (5)
Some studies seem to show a direct decrease in body fat. A 2012 study in 240 Japanese men and women showed decreases in body fat as well as in cholesterol and blood pressure. Researchers suggest continuous consumption of green tea extract contributes to a lower risk of both obesity and heart disease. The effects can be observed in as little as eight to twelve weeks. (19, 20, 21)
Other studies show fat burning increases especially during exercise. Several scientists would suggest green tea extract should be consumed in conjunction with exercise and a balanced diet in order to produce the ideal results. (22, 23)
Though some believed the thermogenic properties of green tea should be attributed to caffeine, the effects of green tea extract have been suggested at for twenty years. Human studies show green tea extract stimulates thermogenesis and fat oxidation to an extent much greater than just the 20-40 mg of caffeine in most capsules. (24, 25)
But weight loss is not a guarantee. Without exercise, green tea extract’s fat oxidation and thermogenic properties can remain dormant, so it may have little to no effect on body composition.
In a Taiwanese study of obese women, green tea extract had no significant effect on body mass. Interestingly, bad cholesterol levels were observed to improve — even though the scientists did not intend on showing any notable change. (26)
400-590 milligrams EGCG daily
The majority of green tea extract supplements contain about 50% ECGC.
The fat burning qualities of green tea extract and ECGC are hindered by frequent caffeine consumption.
Cholesterol: Lipoproteins Beware
You may have heard of “good” and “bad” cholesterol. While high-density lipoprotein (HDL) is a good cholesterol to have in the body, low-density lipoprotein (LDL) is not so great. High levels of small particles of LDL in the blood can cause a buildup of plaque on the inside of the blood vessels. This increases the risk of heart disease, angina, or stroke.
Fortunately, several studies have shown a correlation between green tea extract and lowering of LDL. In a double-blind study of 33 patients with high cholesterol, green tea extract lowered LDL in eight weeks. This study did not see a significant increase in HDL. (27, 28, 29)
Some research suggests green tea extract also increases good cholesterol levels. A 2012 study found that good cholesterol increased while bad cholesterol decreased, in obese patients with hypertension. (30, 31)
A study performed in China found that after 12 weeks, HDL increased and LDL decreased. This study was performed on 240 men and women with high levels of cholesterol who were on a low-fat diet. (32)
250-590 milligrams of green tea extract daily
Oral Health: Goodbye, Bacteria
It’s that polyphenol, ECGC, yet again. Prevalent in green tea extract, ECGC has been shown to promote oral and dental health. Not only may it fight oral cancer, green tea extract possesses antibacterial and antiviral properties. (13, 33)
Green tea extract protects the mouth from bacteria-induced cavities. In particular, the bacterium Porphyromonas gingivalis growth within the mouth may be stopped when exposed to the catechins found in green tea extract. (34)
Green tea extract reduces oral inflammation that results from smoking nicotine. It’s also believed to help prevent contracting the flu because of its antiviral properties, which can cut down on oral inflammation. (35)
Five to six cups of green tea, daily
250-350 milligrams of green tea extract, daily
Blood Pressure: Lowering Systolic and Diastolic Numbers
Also called hypertension, high blood pressure often has no symptoms. Though hard to detect just by feeling, blood pressure checks are a common part of any routine medical checkup. In between visits, it may be a prudent decision to take green tea extract supplements. GTE has been observed to relieve blood pressure.
And actually, both systolic and diastolic blood pressures have been shown to lower with GTE consumption. Often in the same studies with body mass and cholesterol, blood pressure is often measured lower in those consuming green tea extract than control group. (37, 38)
A 2014 study made waves so big, it was featured in Time Magazine. In it, scientists combed through 25 eligible studies to reexamine the blood pressure levels of 1476 subjects. The study concluded that green tea consumption, continuing for more than twelve weeks, resulted in significantly lower blood pressure levels. (39)
The best results in lowering blood pressure seem to come in obese subjects. (40)
370-590 milligrams, daily
Blood Sugar: Better Insulin Sensitivity
A major benefit of green tea extract may be its ability to improve your insulin sensitivity and improve blood sugar levels. Insulin resistance is associated with the development of diabetes.
- Decrease fasting glucose levels and improve insulin sensitivity
- Reduce A1c levels
- Improve insulin production
- Help treat diabetes
In patients with borderline diabetes, GTE decreased glucose abnormalities. (45)
366 milligrams EGCG or 1.5 grams of green tea daily
Green tea extract may help to lower your blood sugar, especially in high doses. However, if you’re taking a medication for blood sugar or struggle with low blood sugar, you should consult with a healthcare professional before taking green tea extract in large amounts.
Other Benefits: Not Enough Research, But a Great Start
There are so many benefits to green tea extract, but not all have been supported by multiple research studies. Some have only been tested in rodents. These are the most promising potential benefits of green tea extract amidst newer research:
- 200-300 milligrams of green tea extract daily may lead to stronger overall heart health. (3)
- GTE could help prevent Alzheimer’s and Parkinson’s disease. Certain types of oxidative stress have been linked to neurodegenerative disease, and green tea’s antioxidant properties fight these. (34, 46, 47, 48, 49)
- GTE may help prevent dementia. (50, 51)
- In a double-blind trial, GTE was administered with L-theanine to successfully improve cognitive function. (52)
- Observed in animal studies as well as a couple human trials, GTE increased endurance and decreased acid buildup after physical exertion. (53, 54, 55, 56)
- Suppression of gastritis induced by H. pylori occurred when tested in Mongolian gerbils. (57)
- GTE was shown to stop muscle cell death in mice. (58)
- The polyphenols in green tea may protect skin from harmful UV rays. (15, 59)
- A lowered chance of nonalcoholic fatty liver disease was observed in obese mice, suggesting GTE may improve liver function. (60)
- GTE can strengthen the capillary blood vessels. (61)
Green tea has fewer side effects than coffee
Stay hydrated when you drink a lot of green tea. Green tea is a diuretic, meaning it will cause a drinker to urinate more frequently. This can lead to decreased levels of sodium or potassium, but those levels seldom reach a sinister point unless you already struggle with sodium or potassium levels.
Green tea extract is also a stimulant. Much like caffeine, green tea can raise alertness and provide bursts of energy. But this can lead to insomnia, jitteriness, or irritability if too much GTE is consumed or if taken late in the day.
The tannin in green tea can cause a very bitter taste. This may occur if green tea leaves are steeped too long, or if a green tea extract supplement is simply a capsule of the tea leaves. (Check individual supplements for process specifications.)
The only side effect of real note has to do with the liver. The European Food Safety Authority (EFSA) recommends daily dosage to remain under 800 milligrams. EFSA has linked excessive GTE consumption with a few cases of liver damage. (62)
Q: What is the recommended dosage for green tea extract?
A: Depending on your intention, between 200 and 600 milligrams daily EGCG. Do not exceed 800 milligrams a day if you’re at risk for liver disease.
Q: Will green tea extract help me to lose weight?
A: Yes. Help. Paired with proper exercise and diet, green tea extract has been shown to increase fat oxidation — which is exactly what we need to break down those fat cells during exercise.
Q: Is green tea extract safe?
A: For almost everyone, green tea extract possesses next to no side effects.
Key Takeaways: Green Tea Extract
- Green tea possesses more health benefits than its cousins, black and oolong tea.
- Since early China, green tea has been touted as a necessity for daily health.
- Rich in antioxidants, green tea extract supplements can help to burn fat, lower cholesterol, promote dental health, decrease blood pressure, and even prevent tumors from forming.
- Side effects for green tea extract are minimal. As long as dosage remains under 800 milligrams, the worst you can expect is excess energy.