Coffee consumption may reduce risk of liver cancer

America Swims on Dunkin’

It’s 6:00 AM and a cell phone rings in the car of a young woman on her way to work in Oakland, California. While reaching for the phone she loses control of her car, which plunges into the estuary between Oakland and Alameda Island. Fortunately, the car doesn’t sink. Staying calm and thinking quickly, the woman breaks a window, pulls herself out of her car, and swims to shore. Onlookers report that as she staggers onto dry land, she is carrying her cup of takeout coffee.

THAT is how much we love our coffee. And research suggests that America’s national java infatuation might actually play a role in our lower rates of a deadly cancer.

Prevention by the cup

In Asia, where consumption of coffee is low, health officials report the highest incidence of liver cancer in the world. But in the U.S., only about 18,500 cases of liver cancer are diagnosed each year.

These numbers don’t necessarily mean that your daily cup-o-joe protects you from this disease, but evidence to support such a claim is mounting.

In the e-Alert “Pure Lard” (8/22/05), I told you about research from Tohoku University in Japan that combined data from two large studies that assessed coffee consumption in more than 60,000 subjects. Results showed that occasional coffee drinkers had 30 percent lower risk of liver cancer compared to subjects who didn’t drink coffee.

Risk was even lower for those who drank coffee daily, which confirms the results of another Japanese study that found regular coffee consumption to be linked with a significantly reduced risk of developing a type of liver cancer known as hepatocellular carcinoma (HCC).

As reported in the International Journal of Cancer, when the Tohoku team singled out subjects who had a history of liver disease, they found a clear link between coffee intake and a lowered risk of liver cancer. The researchers called for further studies to examine the role that coffee might play in the prevention of liver cancer among high-risk patients.

Just one cup per day

Now – fast-forward two years

In a 2007 issue of the journal Hepatology, researchers from the Institute of Pharmacology Research in Milan note that previous research reveals that caffeine and other coffee components have been shown to have beneficial effects on liver enzymes and may play a role in carcinogenic detoxification.

The Milan team conducted a meta-analysis of ten coffee studies that included six case- control studies from Japan and southern Europe, and four cohort studies from Japan. More than 2,200 patients with HCC were included in their analysis.

The combined data produced these results:

• In case-controlled studies, risk of HCC was reduced by more than 45 percent on average
• Subjects who drank the most coffee reduced HCC risk by 55 percent
• Moderate coffee drinkers lowered HCC risk by 30 percent
• Just one cup of coffee per day added to normal consumption reduced HCC risk by more than 20 percent

The Milan team also notes the importance of the similar results from a region where little coffee is consumed (Japan), and a region where the population consumes large amounts of coffee daily (southern Europe).

I have to admit that in these and other coffee studies I find it frustrating that the way coffee is prepared is rarely taken into account. For instance, could a dark roast coffee provide different benefits than a lightly roasted coffee? Even more useful would be a comparison of black coffee to coffee taken with cream and sugar, which must certainly have some effect on the components in black coffee or on the way your body metabolizes those components.

Obviously we still have a long way to go in resolving questions about coffee’s health benefits. Meanwhile, if you have liver problems, talk to your doctor about these studies before increasing coffee intake.

Sources:
“Coffee Consumption and the Risk of Primary Liver Cancer: Pooled Analysis of Two Prospective Studies in Japan” International Journal of Cancer, Vol. 116, No. 1, 8/10/05, interscience.wiley.com
“Coffee Drinking and Hepatocellular Carcinoma Risk: A Meta-Analysis” Hepatology, Vol. 46, No. 2, August 2007, interscience.wiley.com