A small US study suggests that people with type 2 diabetes who drink the equivalent of four cups of coffee or more a day may be causing their blood sugar levels to go up by 8 per cent (compared to non caffeine days), thus making it harder for them to manage their condition.
The study was carried out by Dr James Lane, a psychologist at Duke University Medical Center, in Durham, North Carolina, and colleagues, and is published in the February issue of Diabetes Care.
The results showed that on caffeine days, the patients’ average daily sugar levels went up by 8 per cent. After meals the blood sugar levels were even higher: 9 per cent after breakfast, 15 per cent after lunch, and 26 per cent after dinner.
Lane said they didn’t know how caffeine drove up the glucose levels but they had a couple of ideas.
“It could be that caffeine interferes with the process that moves glucose from the blood and into muscle and other cells in the body where it is used for fuel. It may also be that caffeine triggers the release of adrenaline — the fight or flight — hormone that we know can also boost sugar levels,” said Lane.
Either way, it appears that caffeine causes blood sugar to rise which is bad news for patients with diabetes, he added.