The Mixed News on Green Tea and Cancer
If you’re drinking green tea solely for the cancer protection, you may be interested in the results of a systematic review of studies that involved more than 1.6 million subjects looking at the benefits of green tea.
The review finds “limited” evidence that the green variery of tea offers any protective benefits… though it remains a natural, delicious beverage just the same.
Green tea comes from the same plant, Camellia sinensis, as black and oolong teas -each type is created using different processing methods, and all forms are typically brewed and drunk as a beverage.
Tea extracts can be taken in capsules, or you may find them in skin care products. Tea is safe for most people if you drink it in moderation, though it does have some caffeine (not without its own side effects), and a small amount of vitamin K (an issue if you’re taking anticoagulants like warfarin) per cup.
There’s been a lot of research over the years on tea of the green kind and its benefits to the body, and some evidence that regular drinkers do have lower risks of heart disease and maybe even some forms of cancer.
In China this delicious beverage is routinely used to treat ailments like headaches and depression. There are lots of varieties of tea grown in places all over the globe, which allows for natural differences in taste and color due to growing conditions, harvesting and the type of processing.
The team of researchers who conducted the latest work evaluated existing scientific literature on the green variety of tea – drinking or taking extracts – and identified 51 suitable studies.
Twenty-seven of them were case-control studies, 23 cohort studies and one (on prostate cancer) a randomized controlled trial, the gold standard of clinical evidence.
The studies assessed green tea consumption and cancer of the digestive tract, gynecological cancers including breast cancer, urological cancer including prostate cancer, lung cancer and cancer of the mouth. The studies used were judged to be of medium to high methodological quality.
When it came to digestive cancers and this type of tea the results were “highly contradictory”. Boehm and the team found “limited evidence” in terms of liver cancer risk and conflicting evidence on digestive cancers.
Evidence for bladder and lung cancers was “limited to moderate”, with a discovery that green tea might actually increase the risk of bladder cancer. Green tea appeared to offer no protection for stomach cancers, with results termed “moderate to strong” by the team.
Green tea salvages its good-for-you reputation when it comes to prostate cancer. Studies that are considered higher quality do support a link between green tea (in beverage or extract) and lower risk of disease.
At best, right now the link between green tea and cancer remains unproven though you may have heard reports on studies that link green tea to some impressive health benefits.
Benefits like improving heart health, lowering high cholesterol, reducing the damage caused by free radicals, stopping the abnormal formation of blood clots as well as slowing the progression of cognitive impairment and Alzheimer’s disease.
Further research is needed – a large, carefully designed study that involves subjects who truly drink enough tea as part of their daily intake.
Of course such work is time consuming and expensive – unnecessary if you’re drinking tea for the taste and refreshment of it.
At intakes of 5 to 6 cups a day (about 1,200 milliliters) it is a safe, delicious beverage and although the benefits of green tea have not been unconditionally confirmed, there is still evidence to show it helps with some conditions.