Two studies that examined the link between coffee drinking and cancer found some interesting results: Drinking coffee daily was linked to a decreased risk of liver cancer, and drinking coffee or tea was not associated with the risk of colorectal cancer.
Coffee and Liver Cancer
In the first study, researchers looked at the association between coffee consumption and liver cancer among middle-aged and elderly people in Japan. Those who drank coffee daily, or close to it, had about half the risk of hepatocellular carcinoma (HCC), a type of liver cancer, than people who never drank coffee.
Specifically, among daily coffee drinkers the liver cancer rate was over 200 cases per 100,000 people over 10 years. Among those who never drank coffee the rate rose to nearly 550 cases per 100,000 people. And, the more coffee that was consumed, the lower the HCC risk went.
Past studies have also suggested that drinking coffee may decrease the risk of HCC, but researchers cautioned that, since no distinction was made between caffeinated and decaffeinated coffee, the latter of which is rarely consumed in Japan, the results don’t necessarily indicate that caffeine was responsible for the protective effect.
Coffee and Colorectal Cancer
The second study involved data from two large prospective studies to explore the link between coffee, tea and caffeine and colorectal cancer during close to 2 million person-years of follow-up. Among people who drank caffeinated coffee or tea, no association was found with colon or rectal cancers.
However, those who drank two or more cups per day of decaffeinated coffee had about half the risk of rectal cancer (12 cases per 100,000 person-years of follow-up) as those who never drank decaffeinated coffee (19 cases of rectal cancer per 100,000 person-years of follow-up).
The researchers pointed out that the association might be due to other lifestyle factors, as people who drink decaffeinated coffee may be more health conscious in general than those who drink caffeinated coffee.
News-Medical.net February 15, 2005
Journal of the National Cancer Institute February 16, 2005;97(4):282-292
Journal of the National Cancer Institute February 16, 2005;97(4):293-300
Dr. Mercola's Comment:
Now, before you use the results of these studies as an excuse to head to your local Starbucks, there are several major caveats to consider. For one, the results of countless studies done on coffee tend to conflict quite a bit--so the jury’s still out on what coffee’s real effects of the body may be.
Drinking coffee does have some well documented problems. For instance, it may interfere with your body's ability to keep homocysteine and cholesterol levels in check, most likely by inhibiting the action of the vitamins folate, B12 and/or B6, for one.
So all in all, coffee is clearly not the healthiest liquid to drink—your healthiest choice is pure water--but coffee and caffeine are far less dangerous to your health than fruit juices or carbonated soft drinks.
If you do choose to drink it, though, there are several pieces of advice that you should keep in mind:
Pregnant women (or those who are breastfeeding) should always avoid coffee. Research suggests that drinking more than 300 mg of coffee daily, or the equivalent of two to three 8-ounce cups, may increase the risk of miscarriage, birth defects such as cleft palate and low birth weight.
If you decide to use coffee, please make sure that it is organic. Coffee is one of the most heavily sprayed crops, so drinking organic coffee is a smart way to reduce your exposure to toxic herbicides, pesticides and fertilizers.
If you drink decaf, try to select brands that use the "Swiss Water Process" decaf. This patented method is the best choice, as most of the major brands are chemically decaffeinated, even if it says "naturally decaffeinated" right on the container.
Only use unbleached filters. The other bright white ones, which most people use, are chlorine bleached and some of this chlorine will be extracted from the filter during the brewing process.
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