Green tea, native to China and India, has been consumed and hailed for its health benefits for centuries globally, but has only recently gained popularity in the United States.
Tea is the most consumed beverage in the world behind water. However, 78 percent of the tea consumed worldwide is black and only about 20 percent is green.
All types of tea, except herbal tea, are brewed from the dried leaves of the Camellia sinensis bush. The level of oxidation of the leaves determines the type of tea.
Green tea is made from unoxidized leaves and is one of the less processed types of tea. It therefore contains the most antioxidants and beneficial polyphenols.
Green tea health benefits
Listed below are the possible health benefits associated with green tea. Green tea was used in traditional Chinese and Indian medicine to control bleeding and heal wounds, aid digestion, improve heart and mental health, and regulate body temperature.
Recent studies have shown green tea can potentially have positive effects on everything from weight loss to liver disorders, type 2 diabetes, and Alzheimer’s disease.
It is important to note that more evidence is required before these possible health benefit links are proved definitive:
1) Green tea and cancer prevention
According to the National Cancer Institute, the polyphenols in tea have been shown to decrease tumor growth in laboratory and animal studies and may protect against damage caused by ultraviolet UVB radiation.
In countries where green tea consumption is high, cancer rates tend to be lower, but it is impossible to know for sure whether it is the green tea that prevents cancer in these particular populations or other lifestyle factors.
Some studies have also shown the positive impacts of green tea on the following types of cancer:
- breast
- bladder
- ovarian
- colorectal (bowel)
- esophageal (throat)
- lung
- prostate
- skin
- stomach
Researchers believe that it is the high level of polyphenols in tea that helps kill cancerous cells and stop them from growing. However, the exact mechanisms by which tea interacts with cancerous cells is unknown.
However, other studies have not found that tea can reduce cancer risk. The amount of tea required for cancer-preventive effects also varies widely in studies – from 2-10 cups per day.
In 2005, the Food and Drug Administration (FDA) stated, “there is no credible evidence to support qualified health claims for green tea consumption and a reduced risk of gastric, lung, colon/rectal, esophageal, pancreatic, ovarian, and combined cancers.”
2) Green tea heart benefits
A 2006 study published in the Journal of the American Medical Association concluded that green tea consumption is associated with reduced mortality due to all causes, including cardiovascular disease.
The study followed over 40,000 Japanese participants between the ages of 40 and 79 for 11 years, starting in 1994.
The participants who drank at least 5 cups of green tea per day had a significantly lower risk of dying (especially from cardiovascular disease) than those who drank less than one cup of tea per day.
3) Green tea and lower cholesterol
An analysis of published studies in 2011 found that consuming green tea, either as a beverage or in capsule form, was linked to significant but modest reductions in total and LDL or “bad” cholesterol.
Source: Medical News Today