“Coffee consumption and risk of chronic diseases: changing our views”
This is the title of a recent editorial from the American Journal of Clinical Nutrition (1). There has been much chatter in the popular media about the benefits of coffee; there always is when a guilty pleasure turns out to be not so guilty. But it appears that the scientific community is also perking up – pun intended – to the health benefits of coffee.
What’s the deal with coffee and could it possibly “lower the risk of developing heart disease, asthma, gallstones, Parkinson’s disease, liver cancer and possibly colon cancer” as stated in a Globe and Mail article by Leslie Beck?
Although recently trendy in the media, research into the benefits or harmful effects of coffee has been ongoing for years and there are literally thousands of scientific articles regarding coffee and health. Initially coffee got a bad rap, although when you look critically at the research it’s a bit mystifying as to why that was. A study in the 1960s found a positive correlation between coffee intake and coronary heart disease (CHD) in males; unfortunately, the authors didn’t adjust for smoking. Studies that did adjust for smoking generally found no link between the two and the review concluded that overall there is “no association between coffee consumption and CHD” (2). There is some scientific evidence to show that coffee/caffeine can increase blood pressure immediately after consumption, especially in those who are not habituated, however, a recent meta-analysis did not find that regular coffee consumption negatively impacts blood pressure (3). Finally, at high doses caffeine can affect heart rate but even early on the data wasn’t conclusive regarding the effects of regular consumption of moderate amounts of coffee on heart rates (2).
In 2002 van Dam et al. turned everything topsy-turvy and looked at the BENEFITS of coffee consumption rather than the harmful effects: they actually found a reduction in type 2 diabetes risk (4). Subsequent studies support these initial observations, including a study published last month that looked at the association between coffee intakes and a myriad of chronic diseases in over 40,000 German participants (5). The authors collected data at baseline and 8.9 years later, and found that consuming at least 4 cups of coffee per day did not affect risk of chronic disease. It’s important to note that a cup was defined as 150 mL – not the 20 oz Starbucks – so the above findings are equivalent to 2.5 standard, 250 ml cups of coffee. Furthermore, both decaffeinated and caffeinated coffee were associated with a lower risk of type 2 diabetes, however, no effects were noticed on cardiovascular disease or risk of cancer. Note: this study looked at overall cancer risk, but the effects of coffee on cancer seem to vary by type with some reporting increases and others reductions.
There are some limitations to this study: 1) they didn’t measure coffee consumption at any other point in the study including follow-up, just baseline; and 2) they didn’t consider dietary intakes of saturated fat, cholesterol, sodium, etc. in their analysis. On the other hand, they have a large sample size (although low response rate), adequate follow-up and do control for a number of other risk factors such as smoking, alcohol and exercise. Despite the limitations, their results regarding the effects of coffee consumption on the chronic diseases are supported by others.
Hold up before ordering your next cup of java though. There are some important points that Lopez-Garcia makes in the AJCN editorial which we should all consider:
- If you have other health problems you need to take those into consideration. There is limited research in individuals already presenting with chronic diseases.
- The way the coffee is prepared, filtered vs. non-filtered, may affect the health benefits/risks. Notably, non-filtered coffee may increase total and LDL cholesterol.
- There are a whole host of potential “other” risk factors which are not being controlled for. Epidemiological studies are inherently limited and randomized controlled trials are methodologically and ethically challenging.
- We have not discussed several other health concerns regarding coffee such as insomnia and anxiety. Just because it may improve type 2 diabetes does not mean that coffee won’t impact other yet to be identified parameters of health.
No Baloney’s advice. Seeing as the EPIC study (5) found that only 4.3% of the sample reported NOT consuming coffee, it seems that coffee will continue to be a large part of our culture. A couple of cups a day seems to be safe at the very least and possibly beneficial; interestingly, this intake still fits within Health Canada’s guidelines for caffeine.
Watch out for the extra calories in lattes and other “fancy” coffees though, and at all costs stay away from the flavours – regular and sugar-free! Finally, keep in mind that the research applies to adults not children. Please, think twice before you give your child a babyccino (yes, such a thing exists)!
- Lopez-Garcia E. Coffee consumption and risk of chronic diseases: changing our views. Am J Clin Nutr 2012 [epub ahead of print].
- Rosmarin P. Coffee and coronary heart disease: a review. Prog Cardiovasc Dis 1989; 32:239-45.
- Mesas AE, et al. The effect of coffee on blood pressure and cardiovascular disease in hypertensive individuals: a systematic review and meta-analysis. Am J Clin Nutr 2011; 94:1113-1126.
- Van Dam RM, et al. Coffee consumption and risk of type 2 diabetes mellitus. Lancet 2002; 360:1477-8.
- Floegel A. Coffee consumption and risk of chronic disease in the European Prospective Investigation into Cancer and Nutrition (EPIC) – Germany study. Am J Clin Nutr 2012 [epub ahead of print].