Green tea for weight loss

dubist
dubist Posts: 279 Member
edited October 6 in Social Groups
"Green tea is a rich source of polyphenol catechins. Epigallocatechin gallate (EGCG) is the most active form of the catechins responsible for green tea’s antioxidant, anti-inflammatory, and metabolic effects. Green tea also contains caffeine, which appears to act synergistically with EGCG to assist metabolism. A recent meta-analysis of all human green tea weight loss studies1 found that caffeine-containing green tea works best and produces a statistically significant reduction in body weight, body mass index, and waistline.

In a randomized placebo-controlled trial moderately overweight adults consumed 1900 mgs of green tea catechins per day for 90 days. The green tea also contained 400 mg of caffeine. At the end of the study the green tea group lost on average 2.64 pounds and ¾ inch from their waistline while also reducing body mass index. Not bad considering that no dietary or exercise changes were part of the study.

A 12-week randomized controlled trial3 with 60 obese adults was performed in a hospital setting with all 60 participants placed on a 3 meal per day diet. All their food was prepared for them. Half the group received green tea. The green tea group lost significantly more weight over the 12-week period (24 pounds). The researchers demonstrated that weight loss occurred by green tea increasing energy expenditure and fat oxidation.

Another 12-week randomized controlled trial4 with green tea and obese adults produced little weight loss (less than 1 pound). There was no dietary intervention and the dose of green tea catechins was relatively low (458 mg per day). However, even this modest intake of green tea catechins did produce statistically significant reduction in LDL cholesterol and triglycerides while raising the protective HDL Cholesterol and adiponectin (which prevents insulin resistance). Even though weight was not improved on this dose of green tea it did produce a variety of important metabolic changes that are associated with reduced risk for diabetes and heart disease.

Consumption of 582 mg of green tea catechins per day for 12 weeks in type II diabetic patients5, compared to a control group of diabetic patients, enabled a statistically significant reduction in waistline (abdominal fat). Importantly, green tea catechins were able to promote a restored insulin production by the pancreas. Catechins caused a significant increase in adiponectin , the important hormone signal coming from fat that improves insulin resistance. The combination of diabetic medication and green tea produced a statistically significant reduction in hemoglobin A1C. These results indicate that even modest intake of green tea catechins improves blood sugar control in type II diabetic patients. When blood sugar control is being improved in conjunction with a trend of weight loss then health is being restored.

Consumption of 576 mg green tea catechins per day for 24 weeks in obese children6 found that those who were the most obese had a statistically significant reduction in waist circumference, blood pressure, and LDL cholesterol.

A study published this month in the American Journal of Clinical Nutrition7 showed that a combination of green tea, resveratrol, vitamin E, vitamin C, Omega-3 fatty acids, and tomato extract given to overweight men for 5 weeks raised their adiponectin level by 7%. The researchers documented numerous favorable metabolic changes indicating: modulated of inflammation within white adipose tissue, improved endothelial function of arteries, improved antioxidant function, and increased burning of fat by the liver."


"What the Science Says
Laboratory studies suggest that green tea may help protect against or slow the growth of certain cancers, but studies in people have shown mixed results.
Some evidence suggests that the use of green tea preparations improves mental alertness, most likely because of its caffeine content. There are not enough reliable data to determine whether green tea can aid in weight loss, lower blood cholesterol levels, or protect the skin from sun damage.
NCCAM supports studies to learn more about the components in green tea and their effects on conditions such as cancer, diabetes, and heart disease.

Side Effects and Cautions
Green tea is safe for most adults when used in moderate amounts.
There have been some case reports of liver problems in people taking concentrated green tea extracts. This problem does not seem to be connected with green tea infusions or beverages. Although these cases are very rare and the evidence is not definitive, experts suggest that concentrated green tea extracts be taken with food, and that people should discontinue use and consult a heath care practitioner if they have a liver disorder or develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice.
Green tea and green tea extracts contain caffeine. Caffeine can cause insomnia, anxiety, irritability, upset stomach, nausea, diarrhea, or frequent urination in some people.
Green tea contains small amounts of vitamin K, which can make anticoagulant drugs, such as warfarin, less effective.
Tell all your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care. For tips about talking "
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