IF YOU prefer doughnuts to dumb-bells, you have a high chance of developing diabetes later in life. But if you wash down those doughnuts with at least seven cups of coffee a day you are only half as likely to succumb.
The finding is 鈥渜uite surprising and fairly dramatic鈥�, says Bill Hartnett of UK Diabetes, although the patients鈥� group won鈥檛 be advising people to drink lots of coffee just yet. While there鈥檚 little evidence that one or two cups a day is harmful, some studies suggest that heavy coffee drinkers are unusually sensitive to pain, more prone to panic disorders and can also have higher blood pressure, which increases the risk of heart disease.
The study was done by Rob van Dam鈥檚 team at the National Institute for Public Health and Environment in the Netherlands, which analysed data on 171,111 men and women. The team found that those who drank seven or more cups of coffee a day were 50 per cent less likely to develop type 2, or adult onset, diabetes than those who drank two cups of coffee or fewer a day (The Lancet, vol 360, p 1477). This was despite the fact that the heavy coffee drinkers tended to have sedentary lifestyles, which increases the risk of developing diabetes.
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鈥淚t鈥檚 too early to get excited,鈥� cautions Edwin Gale, a diabetes specialist in Britain at the University of Bristol. It may just be that coffee drinkers behave differently, he says. For example, they might be less likely to visit doctors and get diagnosed. The finding needs to be confirmed, Van Dam acknowledges, and the mechanism worked out.
Type 2 diabetes used to appear mainly in older people, but as levels of obesity have increased in children so too has the prevalence of the disease. It鈥檚 a serious disorder 鈥� high blood sugar levels damage many organs, and can lead to anything from blindness to kidney failure.
It usually occurs when the body becomes less sensitive to insulin, the hormone that tells cells to mop up excess blood glucose. Caffeine isn鈥檛 an obvious remedy for type 2 diabetes, because its immediate effect is to lower sensitivity to insulin.
But the long-term effects of caffeine are unknown, Van Dam points out. And the protective effect could be due to other components of coffee, such as chlorogenic acid, magnesium and potassium. His team now plans to assess the long-term effects of decaffeinated coffee.