Why drink coffee? Ask any of the over 60 percent of Americans who drink coffee and the answer will likely be its energy boosting ingredient: caffeine. For some, this benefit is outweighed by the beverage's tendency to aggravate anxiety, heartburn, and insomnia. But new research shows that those who drink coffee are getting more than just bang for their buck (or $2.36, the average price for a cup).
Emerging scientific evidence suggests that coffee also benefits conditions ranging from skin cancer, to Parkinson's, to liver disease. But the news is confusing -- a recent article in the New England Journal of Medicine concludes all-cause mortality was lowered by over 10 percent at 13-year follow-up in coffee drinkers, and yet a study published in Mayo Clinic Proceedings demonstrates a connection between heavy coffee intake (more than four cups a day) and all-cause mortality. More research is needed to clarify the mixed messages and determine if coffee plays a causative role in any of these relationships.
Let's take a closer look at some specific studies:
A large study of 50,000 older female health workers in Boston showed a reduced incidence of depression in those who drank 2-3 cups of caffeinated coffee (15 percent) compared to those who drank one or less cup of coffee, and an even greater decreased risk of depression (20 percent) in those who drank four or more cups. That may sound like a lot of coffee, but considering a cup of coffee is 8 ounces, at 16 ounces a single Starbucks medium (or "Grande") gets half the job done.
A 13-year look at over 80,000 subjects in Japan recently revealed that drinking coffee once a week was associated with a 20 percent decreased risk in stroke compared to seldom coffee drinkers.
Data from the same cohort showed a 17 percent reduction in Basal Cell Carcinoma (the most common type of skin cancer) in those who drank 3 cups of caffeinated coffee a day compared to those who drank less than 1 cup of coffee per month. Decaffeinated coffee did not achieve the same results. Other sources of caffeine, including chocolate, tea, and soda did show a protective effect, indicating that it is likely the caffeine and not the coffee bean itself behind this health benefit.
As the obesity epidemic continues, Non-Alcoholic Fatty Liver Disease (NAFLD) is on the rise, afflicting about 25 percent of the population. Coffee consumption is now credited with reducing the progression of fibrosis in NAFLD patients. Evidence suggests that coffee is also associated with curtailed progression of liver disease in people with liver fibrosis and Hepatitis C. But take note, brew through a filter to help your liver. Filtering coffee removes cafestrol, a chemical that affects the liver by increasing LDL (the "bad" cholesterol).
A recent meta-analysis (a study analyzing many studies) looking at the relationship between coffee drinking and gallstones revealed that the relationship is still inconclusive. While the evidence favors the position that coffee may be protective against gallbladder disease, it is not enough to suggest prescribing the caffeinated beverage to ward off illness.
There has long been controversy surrounding the consumption of coffee in those who have heart disease, as coffee raises blood pressure, a known risk factor for heart disease. Recent studies have shown that caffeine when consumed in coffee causes an only temporary increase in blood pressure, and the risks may outweigh the benefits. New research shows that two cups of coffee a day may keep heart failure away (this study did not separate out regular from decaf coffee drinkers).
Because Scandanavian countries have amongst the highest caffeinated coffee consumption and highest exfoliation glaucoma (leading cause of secondary glaucoma) rates in the world, investigators at Brigham and Women's Hospital in Boston sought to find if there was a relationship between these two statistics. Looking at two large cohorts of health professionals over 40 years of age, drinking 3 or more cups of caffeinated coffee per day, but not other caffeinated products, increased the risk of developing the condition.
A cohort of nearly half a million Americans showed that drinking 4 or more cups of coffee per day, compared to drinking no coffee, reduced the risk of colorectal cancers. Unlike some of the other studies mentioned, there was some evidence that decaffeinated coffee is also beneficial suggesting that the benefit lies in the coffe bean itself and not due to caffeine.
What about decaf?
Although many of the benefits of coffee stem from the caffeine therein, caffeic acid (a non-caffeinated, and despite its name, unrelated compound) is part of the cancer fighting phenol group. Caffeic acid has been shown to demonstrate anti-oxidant and anti-carcinogenic properties.
Coffee, especially caffeinated coffee, may provide a myriad of health benefits, but the jury is still out. Drinking coffee in moderation is safe, but don't be fooled by sweetened beverages with coffee flavor. It's the coffee bean, not the cream and sugar, that may be good for you! Again, if coffee plagues you with side-effects, you should not start or continue drinking it for the purported health benefits.
To a life of boundless health,
Co-authored by Danielle Flug Capalino, MSPH, RD
For more by Gerard E. Mullin, M.D., click here.
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