Green tea catechins such as EGCG have effectively been shown to increase metabolism as an aid to weight loss and have demonstrated a long history as a potent tool to fight many different types of cancer. Compounds in green tea act as powerful antioxidants that can promote apoptosis or programmed cell death, a mechanism missing in cancer cells that permits uncontrolled cell growth.
Researchers from Rutgers University have published the result of a study in the journal Food and Function that explains a synergistic health-promoting relationship when green tea polyphenols and the flavonoid quercetin are provided through diet or supplementation. Quercetin helps boost the levels of green tea polyphenols in cancer cells to decrease methylation of their anti-cancer compounds, effectively increasing the green teas potency as a cancer-fighting agent.
Quercetin boosts green tea antioxidant capacity two to fourfold to fight cancer development
In past studies, scientists have demonstrated that green tea catechins undergo extensive methylation after ingestion, lowering the effectiveness of the health-promoting compounds to shield against cancer proliferation. Quercetin is a known inhibitor of methylation in normal metabolism, and a study was conducting using mice to determine if the naturally occurring flavonoid found in many fruits and vegetables could increase the potency of green tea catechins (specifically epigallocatechin gallate or EGCG).
Mice with severe combined immunodeficiency were given brewed green tea and a diet supplemented with 0.4 percent quercetin alone or in combination for a period of two weeks. Researchers determined that the supplemented group experienced a two to three times increase of total and non-methylated EGCG in the lung and kidney along with an increasing trend in the liver.
The study found that combining quercetin with fresh brewed catechins from green tea increased the cellular adsorption of EGCG four times in lung cancer cells and two times in kidney cancer cells, dramatically increasing the effectiveness of this natural cancer fighting compound in vivo. Additionally, quercetin decreased methylation of green tea polyphenols, which would otherwise limit their chemopreventive potential.
The research team concluded that “in order to have a maximum anticancer effect, green tea or green tea extract should be used together with quercetin.” They noted that green tea catechins exhibit higher antioxidant potential than either vitamin C or E, and indicated that consuming the beverage was associated with reduced risk for a number of forms of malignancy including skin cancer, breast cancer, lung cancer, colon cancer, esophageal cancer and bladder cancer. Three to five cups of fresh-brewed green tea daily combined with quercetin from fruits and vegetables or supplementation are recommended to synergistically boost the cancer fighting abilities of EGCG catechins.