More Good News for Coffee Drinkers

When I first started practicing, fresh out of my internal medicine residency and board certification, we were taught that consuming more than five cups of coffee per day increased your chances of developing pancreatic cancer. Thankfully that theory has been proven to be false.

Last week I reviewed a publication in a peer reviewed journal which showed that if you infused the equivalent of four cups of coffee into the energy producing heart cell mitochondria of older rodents, those mitochondria behaved like the mitochondria found in very young healthy rats. The authors of that article made the great leap of faith by suggesting that four cups of caffeinated coffee per day was heart healthy.

This week’s Journal of the American Medical Association Internal Medicine published a study which said if you drank eight cups of coffee per day your mortality from all causes diminished inversely. Their study included individuals who were found to be fast and slow metabolizers of caffeine. It additionally made no distinction between ground coffee, instant coffee or decaffeinated coffee.

The research study investigated 498,134 adults who participated in the UK Biobank study. The mean age of the group was 57 years with 54% women and 78% coffee drinkers. The study participants filled out questionnaires detailing how much coffee they drank and what kind. During a 10 year follow-up there were 14,225 deaths with 58% due to cancer and 20% due to cardiovascular disease. As coffee consumption increased, the risk of death from all causes decreased. While instant coffee and decaffeinated coffee showed this trend, ground coffee showed the strongest trend of lowering the mortality risk.

This is an observational study and, by design, observational studies do not prove cause and effect. It is comforting to know however that having an extra cup or two seems to be protective rather than harmful. At some point a blinded study with true controls will need to be done to prove their point. If the caffeine doesn’t keep you up or make you too jittery, and the coffee itself dehydrate you or give you frequent stools, then drink away if you enjoy coffee in large volume.

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