Correlations between coffee consumption and the incidence of cancer

I was alerted by one of my readers to a new paper, published in the American Journal of Clinical Nutrition, which indicated that drinking more than 4 cups of caffeinated coffee per day is protective against colon cancer, in a study of nearly 490,000 people who self-reported for a decade.

Self reporting is not the most accurate method of collecting data, so even a study that involves this many participants needs to be viewed with caution. Likewise, there was nothing to say, in this publication, that the coffee consumption itself was the main factor driving the lower rates of colorectal and skin cancer that were reported – in other words, corrections for other lifestyle factors were not made. This, therefore, leaves the interpretation of such data wide open, and the authors of the study admit this. Comments to the editors of the American Journal of Clinical Nutrition point out that this study failed to document whether the coffee was filtered or unfiltered (this makes a difference in removal of compounds that cause elevation in blood cholesterol, and therefore seem to have a correlation with higher incidence of heart disease in those who drink large amounts of coffee). Likewise others commenting on the research cite scientific studies that link coffee consumption in pregnant women to the higher incidence of childhood leukaemia in their offspring, and the increased incidence of liver cancer. One other study, published in 2011, indicated that drinking 6 cups of coffee per day reduced the incidence of aggressive prostate cancer.

The conclusions of some authors indicate that further research is needed into the compounds in coffee that might have either beneficial or negative effects, determined by methods of preparation, such as ground coffee, light or dark roast, filtered or unfiltered, espresso, and even the origin of the beans themselves.

I think what is really needed is to get to the bottom of who funds these studies. When I asked Brian Clement about this kind of research, he called it “cheque-book science”, meaning that the coffee industry pays researchers to, for example, “find something good in coffee that we can claim has health benefits”, undoubtedly to boost sales. We all know that this goes on, but sometimes studies such as these can appear to be quite compelling.

On the flipside, we know that caffeine is an addictive drug. Researchers at Johns Hopkins University have discovered that even low to moderate consumption (1 mug per day) is enough to produce withdrawal symptoms when the coffee drinker stops. Caffeine consumption causes excessive neuron firing in the brain, which leads to stimulation of the pituitary gland, in turn stimulating the adrenal glands to produce more adrenaline. Left unchecked in the regular coffee drinker, adrenal exhaustion can quickly follow. The study linking coffee consumption with reduced cancer rates only showed a positive correlation when the coffee was caffeinated; decaffeinated products indicated no benefit. As an aside, since the decaffeination process involves the use of turpentine and embalming fluid, both known carcinogens, it is hardly surprising that “decaff” showed no benefits in cancer reduction!

So, what shall we do here? Should further studies into potential beneficial types of coffee be funded? No doubt the coffee industry believes so, and will continue to provide researchers with financial incentives. Should coffee drinkers continue to enjoy their daily fix in the hope that their habit will give them some protection? Are coffee drinkers even considering that their chosen drug might have health benefits, however tenuous or controversial the link? Does anyone actually care?

My suggestion is as follows: why don’t we just focus on doing the things that we already know protect us against cancer, that have no adverse side effects? Come on folks – admit that if you drink coffee it is a habit. Don’t hide behind promises of potential benefits – if you’re going to drink the stuff, do it because you like it and you want to! If, however, you want to maximise your health potential, eliminate the habit. Coffee is addictive. It is dehydrating and overstimulating. It strongly correlates with osteoporosis (don’t even get me started on that one!). You will look and feel better without it. If you want a pick-me-up, have a green juice instead!

About Max Tuck

Hippocrates Health Educator. Long term living foods vegan. Athlete, lecturer, author of four books (with the 5th coming soon) and firm advocate of healthy living.
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