Heavy Coffee Drinking Increases Risk of Early Death
Contradicting the results of several previous studies, a large study published in the Journal Mayo Clinic Proceedings has found that heavy coffee drinking is not only not healthy, but speeds up death – especially among those under the age of 55.
Long-term study on coffee focuses on accuracy
The study followed 43,727 adults through a span of seventeen years – equating to 699,632 person-years. The data was collected by direct medical examination together with questionnaires. The medical exams consisted of blood chemistry, blood pressure, electrocardiography (EKG) together with exercise testing.
During the 17-year follow-up period 2,512 people died, and 804 of them were from cardiovascular disease. Those who drank more than 28 cups of coffee a week were 21% more likely to die during the study period.
The 28 cups per day equates to four cups a day. The research found that three cups of coffee per day or less had little effect on health but those with four cups or more a day had the noticeable increase of death rate.
More alarming is that among men under the age of 55 there was an increased risk of death by 56% and among women under 55 the risk of death doubled – 100% increase.
The concept of increased risk of death translates to increased risk of early death because during that 17 years – after canceling out other factors like smoking – more people who drank 4+ cups of coffee a day died, and fewer died who drank 3 or less cups a day.
Other studies estimate that 400 million cups of coffee are drank per day in the U.S. – an average of 3.1 cups per day for adults. And about 60% of adults are heavy coffee drinkers.
The researchers eliminated from the data other potential comingling effects such as smoking. However, they could not eliminate related lifestyle factors such as sleep – meaning that heavy coffee drinking is also associated with increased risk of insomnia and insomnia is related to higher risk of chronic diseases.
Dr. Carl Lavie, one of the study’s authors, pointed out that the association was not with caffeine because the early death was not associated with heart disease – which is specific to caffeine use. He also added that fewer than four cups did not add or decrease mortality risk.
In their conclusion the authors added:
“On the basis of these findings, it seems appropriate to suggest that younger people avoid heavy coffee consumption (ie, averaging >4 cups per day).”
Previous coffee studies contradicted?
While this study seems to contradict a previous study published last year by the National Institutes of Health. This study followed 400,000 people between 50 and 71 years old for 12 years and found that drinking three or more cups of coffee a day reduced the risk of death by about 10% – and less for those drinking fewer cups a day. This result, by most evidence standards, is not considered very significant. Furthermore, the study only assessed coffee consumption through survey on one occasion – so did not determine if the heavy coffee consumption was ongoing. This study also found that heavy coffee drinking slightly increased the risk of cancer among the men.
The current study was performed over a longer period with greater levels of examination and assessment.
So what is it about coffee that is so bad? And isn’t it a source of antioxidants?
Yes coffee can be a source of antioxidants, but as coffee beans are over-roasted – as they are in most commercial facilities – a number of these are lost, and unhealthy metabolites are produced. These include acrylamide and others.
Acrylamide is formed when starches combined with the asparagine amino acid are overcooked – typically achieved with frying, roasting and other high heat cooking.
Acrylamide has been linked with cancer in animal studies, but there have been few studies confirming this in humans. Acrylamide has, however, been linked with nerve damage in humans.
Green coffee beans are loaded with antioxidants with little acrylamide.
This relationship between overprocessing and chronic diseases exists nearly across the board with many different foods – foods that are healthy in their natural states but unhealthy in their over-processed state.
Other considerations, including sleep
Another consideration is that heavy coffee drinking has been shown to interrupt sleep – and a lack of sleep is associated with early mortality.
There has also been some indication that coffee may interfere with maintaining healthy homocysteine levels.
This all comes with a recent review from Italy showing coffee decreases mortality by about 12%. Certainly the evidence is confusing – and perhaps there is a dichotomy regarding the difference between types of coffee. Perhaps European coffees are produced with better and provide fewer acrylamides. Or perhaps they add less junk such as sugar to their coffees – which may also be related to the finding that younger people appear to have more deleterious effects from coffee.
Part of the issue is that smoking and coffee drinking had to be separated in all of the studies reviewed. This may well be shifting the data towards those who have more healthier, active lifestyles in general as they age – those who drink coffee but do not smoke.
While the results of this new study seem very clear – and the research was conducted in a more focused manner – there is still more to learn about coffee.
Meanwhile, the data showing green tea – considered a coffee substitute – has been clear: Green tea is a great source of antioxidants, and is clearly anti-carcinogenic as well.
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