We Brits, it seems, have an insatiable appetite for coffee matched only by our unquenchable thirst for news stories about whether it will kill us or make us live for ever. Now a new study has suggested that drinking coffee might lower your risk of type 2 diabetes.
Coffee has come a long way since it was first imported into Western Europe in 1615 after news of the 'wine of Araby' spread to the West. Some religious speakers condemned coffee as the 'bitter invention of Satan'. Their attempt to garner support from the Pope for their cause backfired when, after tasting it, he gave the drink the Papal seal of approval, and by the mid-17th century the cafe culture had begun. By the turn of the 18th century there were over 3,000 coffee houses in London alone, where business was done while they sipped their brew. Indeed, the London Stock Exchange and Lloyds of London both started life as coffee houses.
Fast forward to 2014, and the UK consumes about 70 million cups of coffee a day. Hardly surprising, then, that people have an interest in whether it's bad (or good) for them. One of the commonest questions I'm asked is whether coffee dehydrates you. It doesn't, if you stick to moderate intake (up to four to five cups a day), and in fact it can contribute to your daily fluid intake. (1) Next there's whether it kills you - this after a study last year suggesting that people who drank more than 28 cups a week hit the headlines. (2) What many of the newspapers failed to point out was that there was no health risk found for people drinking up to four cups a day, or that another study the previous year found that people who drank coffee had lower death rates than those who didn't. (3)
Next on the list is coffee and heart health - fuelled when Cherie Blair famously banned her Prime Minister husband from drinking coffee and he had minor heart surgery. The British Heart Foundation has looked at all the evidence and concluded that for healthy people drinking up to four to five cups a day, there is no heart risk. (4)
So what about type 2 diabetes? Just last year, a study suggesting coffee might increase your risk of type 2 diabetes hit the headlines. (5) In fact, it was a small study in rats already being fed a high-fat diet. By contrast, studies looking at up to 30,000 humans have consistently shown that those who drink coffee are less likely to develop type 2 diabetes. (6,7) These studies aren't perfect, and they're not enough for me to start actively plying my patients with coffee if they don't drink it already. But they're certainly a strong indicator that there is nothing to worry about.
There are some conditions where caffeine in any form can make matters worse for some people - these include migraines, irritable bowel syndrome and urge incontinence. If you suffer from any of these, it may be worth cutting out caffeine for a couple of weeks to see if your symptoms improve.
The other exception to the 'up to four to five cups a day' rule is pregnant women - they should stick to no more than 200 mg of caffeine a day from all sources (a cup of contains about 50 mg of caffeine and a cup of brewed coffee or a mug of instant coffee about 100 mg). But for everyone else, the news is remarkably reassuring. Do I consider I lead a healthy lifestyle? Absolutely, as much as I can. Do I lose sleep over my three cups of coffee a day? Not unless I drink them just before bedtime.
2) Liu J, Sui X, Lavie CJ, et al. Association of coffee consumption with all-cause and cardiovascular disease mortality.Mayo Clin Proc 2013; DOI:10.1016/j.mayocp.2013.06.020.
4) The British Heart Foundation, http://www.bhf.org.uk/publications/view-publication.aspx?ps=1000767
5) Mubarak A et all. Supplementation of a High-Fat Diet with Chlorogenic Acid Is Associated with Insulin Resistance and Hepatic Lipid Accumulation in Mice. Journal of Agricultural and Food Chemistry. April 2013, 61 (18), pp 4371-4378
6) Pereira A et al. Coffee consumption and the risk of type 2 diabetes. Arch Int Med 2006; 166: 1311-1316
7) Bidel S et al. European Journal of Clinical Nutrition (2007), 1-8
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