A LETTER FROM: BOSTON, USA

– Written by Sanjiv Chopra, USA

Coffee is one of the most widely consumed beverages in the world. Approximately 100 million Americans drink coffee on a daily basis and each day, 400 million cups of coffee are consumed in the United States alone. Worldwide, more than 2.25 billion cups of coffee are consumed each day. On a per capita basis, Finland, Sweden and Switzerland lead the world in coffee consumption.

THE LEGEND OF COFFEE

According to legend, coffee originated in Ethiopia, in a small village named Kaffa. There was a shepherd by the name of Kaldi who would take his sheep to pasture. He noticed that in one particular field, the sheep were very frisky and animated. They were consuming a red berry. He decided to make a brew out of this and really enjoyed it. There was a monastery nearby and a monk, as he passed Kaldi, scolded him saying, “You have partaken of the devil’s fruit.” Kaldi ignored him until a while later the monk asked to taste the drink. He, too, enjoyed the brew and was able to stay up for the late night prayers. Coffee spread to Arabia, India and South America. Some 700 years ago, a group of well-meaning individuals petitioned Pope Vincent III, saying that coffee is truly the devil’s drink and needs to be banned. The pope said, “Before I ban it, let me taste it,” and when he did so he proclaimed, “Coffee is so good, the infidels should not have exclusive use of it.”

HEALTH BENEFITS OF COFFEE 

One of the most striking benefits of coffee was first noted by Dr Arthur Klatsky (USA) and colleagues in 1992. They noted an inverse relationship between coffee and liver cirrhosis. That study and other subsequent studies consistently showed that coffee appears to be hepatoprotective. Coffee drinkers have lower levels of liver enzymes, less liver fibrosis, a significant reduction in hospitalisation and mortality from chronic liver disease and a marked decrease in the incidence of primary hepatocellular carcinoma or hepatoma. Hepatoma is the fourth leading cause of cancer mortality in the world. For decades, physicians and scientists have been mystified as to why only a minority of patients, despite drinking a pint of whiskey or a litre of wine a day, develop cirrhosis of the liver. In a follow-up study, investigators noted that one cup of coffee a day decreased the chance of individuals developing alcoholic cirrhosis by 20%, two cups by 40% and four cups by 80%. Thus, there seems to be a dose-dependent effect lending credibility to these epidemiological studies. As we all know, epidemiological studies do not determine mechanisms or causality but when there is such a strong protection, and it is dose-dependent, one has to pay attention to it.

But what is the mechanism of protection? We don’t know the precise mechanism. What we do know is that coffee has a thousand constituents in addition to caffeine. Constituents such as cafestol and kahweol are protective in animal studies of acute liver injury. In a study published from the Harvard School of Public Health and the Beth Israel Deaconess Medical Center, coffee drinkers were shown to have lower levels of C-reactive protein and of tumour necrosis factor-alpha. Coffee drinkers were also noted to have higher levels of plasma adiponectin. Of interest, low levels of plasma adiponectin have been linked with aggressive liver disease.

Coffee is also insulin-sensitising. One would therefore suspect that coffee might protect against type 2 diabetes. Indeed, a number of studies have shown that coffee drinkers have a lower risk of developing type 2 diabetes. Of note, this protection is seen with both regular and decaffeinated coffee whereas for liver disease, the association has only been seen with regular coffee. Individuals who consume six cups of coffee a day have a 30 to 40% reduction in risk of developing type 2 diabetes. And individuals with Type 2 diabetes who consume two cups of coffee a day have a 20 to 30% reduction in cardiovascular mortality.

In addition to protection against primary hepatocellular carcinoma, in the last couple of years published studies have shown that coffee drinkers have a lower risk of developing metastatic prostate cancer, skin cancer, endometrial cancer and oropharyngeal cancer.

Recent studies have also shown that coffee drinkers have a lower risk of developing Parkinson’s disease and cognitive decline. Thus, in examining the health benefits of coffee, one can observe that coffee drinkers have a lower risk of developing liver disease, Type 2 diabetes, a number of common cancers and debilitating neurological disorders such as Parkinson’s disease and dementia.

IS THERE A DOWNSIDE TO COFFEE? 

Coffee may worsen gastroesophageal reflux disease, incite diarrhoea in patients with irritable bowel syndrome and may produce palpitations in certain individuals. Although many physicians have cautioned pregnant women not to consume more than a cup of coffee per day for fear of miscarriage, the American College of Obstetricians and Gynaecologists issued a statement in 2010 that stated that moderate caffeine intake – less than 200 mg a day – will not increase the risk of miscarriage or preterm birth.

All in all, the benefits seem to far exceed the side-effects.

If coffee has all these miraculous health benefits, coffee drinkers should have lower mortality rates. A landmark study was published by Dr Freedman and colleagues in the New England Journal of Medicine on 17 May 2012. In a large prospective study, the association of coffee drinking with total and cause-specific mortality was examined in 229,119 men and 173,141 women in the National Institutes of Health – AARP Diet and Health Study. The individuals in this study were 50 to 71 years of age. Participants with cancer, heart disease and stroke were excluded. In this large prospective cohort study, there were significant inverse associations of coffee consumption with deaths from all causes and specifically with deaths due to heart disease, pulmonary disease, diabetes, stroke, infections and injuries and accidents.

WHAT EFFECT DOES COFFEE HAVE ON ATHLETIC PERFORMANCE?

The International Society of Sports Nutrition's position on caffeine and performance was published in January of 2010. They concluded that caffeine is effective for enhancing sport performance in trained athletes when consumed in low to moderate dosages (306 mg/kg). Caffeine has been shown to enhance vigilance during bouts of extended and exhaustive exercise. Caffeine is ergogenic for sustained maximal endurance exercise. Athletes who partake in soccer and rugby, both of which have in common intermittent bursts of activity, may benefit from drinking coffee. The scientific literature does not support that drinking coffee produces any harmful change in fluid balance that might negatively affect sport performance.

Caffeine was once a banned substance according to the World Anti-Doping Agency, but was removed from the Prohibited List in 2004. Its use in sport is not prohibited. Currently, caffeine is part of WADA's Monitoring Program which includes substances which are not prohibited in sport, but which WADA monitors in order to detect patterns of misuse in sport.

I think, given the robust body of literature published in peer reviewed journals, one can conclude that coffee is truly a miracle drug. None of these studies have been sponsored by Starbucks or the Columbia Federation of Coffee! Voltaire, the French enlightenment writer, historian and philosopher was famous for his wit. He was born in 1694 and lived for 83 years. It is reputed that he drank 50 to 72 cups of coffee a day.

Tom Standage, in a fascinating and delightful book entitled, The History of the World in Six Glasses, writes:

“In the 17th century, in London, an anonymous poem was published in which wine was denounced as the “sweet Poison of the treacherous grape”.  Beer was condemned as the “foggy ale that beseig’d our Brains.” Coffee, however, was heralded as…

…that Grave and Wholesome Liquor,

That heals the Stomach, makes the Genius quicker,

Relieves the Memory, revives the Sad,

and cheers the Spirits, without making Mad.”

I hope you have enjoyed reading this article and found it informative. As I write it is 9 am and I am off to a very important meeting where I know I will be able to enjoy my third freshly brewed cup of this magical elixir!

Sanjiv Chopra M.B.B.S., M.A.C.P.

Senior Consultant in Hepatology

Harvard Medical School

Beth Israel Deaconess Medical Center

Boston, USA

References

1. Klatsky A, Armstrong MA. Alcohol, smoking, coffee and cirrhosis. Am J Epidemiol 1992; 136:1248-1257.
2. Tverdal A, Skurveit S. Coffee intake and mortality from liver cirrhosis. Ann Epidemiol.2003; 13:419-423.
3. Larsson SC, Wolk A. Coffee consumption and risk of liver cancer: a meta-analysis.Gastroenterology 2007; 132:1740-1745.
4. Modi AA, Feld JJ, Park Y, Kleiner DE, Everhart JE, Liang TJ et al. Increased caffeine consumption is associated with reduced hepatic fibrosis.Hepatology2010; 51:201-209.
5. Lopez-Garcia E, van Dam RM, Qi L Hu FB. Coffee consumption and markers of inflammation and endothelial dysfunction in healthy and diabetic women. Am J Clin Nutr 2006; 84:888-893.
6. Huxley R, Lee CM, Barzi F, Timmermeister L, Czernichow S, Perkovic V et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med 2009; 169:2053-2063.
7. Wilson KM, Kasperzyk JL, Rider JR, Kenfield S, van Dam RM, Stampfer MJ et al. Coffee consumption and prostate cancer risk and progression in the health professionals follow-up study. J Natl Cancer Inst 2011; 103:876-884.
8. Freedman NK, Park Y, Abnet C, Hollenbeck AR, Sinha R. Association of coffee drinking with total and cause-specific mortality. N Engl J Med 2012; 366:1891-1904.
9. Goldstein E, Ziegenfuss T, Kalman D, Kreider R, Campbell B, Wilborn C. International society of sports nutrition position stand: caffeine and performance. J Int Soc Sports Nutr 2010; 7:5.
10. Standage T. A History of the World in Six Glasses. Walker Publishing Company, New York 2005.

Image via Richard Masoner