The antioxidants called catechins in green tea is the main reason for the many benefits green tea provides.
It is very important to be insulin sensitive and have good glucose control because elevated blood glucose levels and insulin resistance cause inflammation and damage tissue.
When 17 studies were reviewed which included 1133 participants, the researchers found that green tea consumption significantly reduced fasting blood glucose and hemoglobin A1c (Hb A1c) (Liu K, et.al., 2013). Subgroup analysis also found that green tea significantly reduced fasting insulin.
As you get more insulin sensitive, you don’t need as much insulin to transfer the blood glucose into the cells. As blood levels of insulin go down, you will also start to use more fat for energy.
The following study investigated green tea extract in capsule form instead of drinking green tea. (Bogdanski P, et.al., 2012).The participants were obese, had high blood pressure and took either a capsule of 379 mg of green tea extract or a placebo capsule for 3 months. This was the results.
Total cholesterol, LDL (low-density lipoprotein) and triglycerides decreased, while HDL (high-density lipoprotein) increased in the treatment group, but not in the placebo group. The group taking the green tea extract also had a significant decrease in diastolic and systolic blood pressure as well as a significant decrease in TNF-alpha and CRP, both inflammatory markers. Glucose, insulin and insulin resistance also improved.
This is all very good, but you need to be careful when you buy green tea.
When black, green, white and oolong tea sold in tea bags were steeped for 3-4 minutes and the tea tested, this is what was found (Schwalfenberg G, et.al., 2013).
73% of teas brewed for 3 minutes and 83% brewed for 15 minutes had lead levels considered unsafe for consumption during pregnancy and lactation. Aluminum levels were above recommended guidelines in 20% of the brewed teas.
No mercury was found at detectable levels in any of the brewed samples.
Tea can possibly also be contaminated with pesticides.
You need to be sure that the tea you buy is of high quality and not grown in contaminated soil. This is something to keep in mind when you buy green tea extract also.
Bogdanski P, Suliburska J, Szulinska M, Stepien M, Pupek-Musialik D, Jablecka A. Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients. Nutr Res. 2012 Jun;32(6):421-7. doi: 10.1016/j.nutres.2012.05.007.
Liu K, Zhou R, Wang B, Chen K, Shi LY, Zhu JD, Mi MT. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013 Aug;98(2):340-8.
Schwalfenberg G, Genuis SJ, Rodushkin I.The benefits and risks of consuming brewed tea: beware of toxic element contamination. J Toxicol. 2013;2013:370460.
The Better Green Tea Formula
Polyphenols (catechins) are the active ingredients in green tea providing a variety of benefits.