When it comes to trouble brewing in our blood vessels we’re familiar with the image of fatty plaque sticking to artery walls and raising the risk of heart attack. We’re not so savvy about that other threat that can hide inside blood vessels: rising levels of blood sugar.
Around 16 per cent of Australians now have levels of blood sugar that are too high. That’s not high enough to mean full blown type 2 diabetes but enough to put you in pre-diabetes land where too much blood sugar – or glucose as doctors tend to call it – can begin harming arteries.
“It acts like rust in the blood vessels,” explains Professor Neale Cohen, General Manager of Diabetes Services at the Baker IDI Heart and Diabetes Institute. “But compared with our awareness of keeping cholesterol levels healthy or even getting checks for breast cancer, there’s less understanding of the need for healthy levels of blood glucose.”
But just how much is the sugar in our diet to blame for too much sugar in the blood?
It’s a player, but not the only one says Cohen, who nominates obesity and sedentary living as the two main drivers, although genes also play a part. Being overweight can make it harder for the hormone insulin to control blood glucose levels, while too much sitting around gives our muscles so little to do that they don’t soak up enough of the glucose in our bloodstream that’s meant to be used for fuel.
As for what we eat, too much sugar adds to the kilojoule load that can make our waistlines bigger. But does fructose, the sugar found naturally in fruit and which makes up 50 per cent of cane sugar, (the other 50 per cent is glucose) promote diabetes and pre-diabetes in other ways?
“It may turn out to be more toxic than glucose, but whether fructose in processed foods is a major problem with diabetes isn’t clear cut – at the moment the evidence is inconsistent,” Cohen says.
With fresh fruit, its sugar content comes packaged with fibre and important nutrients so it’s good to eat in moderation, he adds – although as with too much of anything, too many pieces of fruit can add to the kilojoule load.
It makes sense to prefer slow burning low GI carbohydrate foods like legumes and whole grains over refined carbohydrates that, in excess, can contribute to raised blood glucose, says Cohen. But singling out sugar in the diet as the main cause of diabetes and pre-diabetes isn’t helpful if it distracts us from what he sees as a bigger culprit – the fact that we’re more inactive now than at any other time in human history.
Yet the noise over the role of sugar seems so much louder than the noise over inactivity. Last year after actor Alec Baldwin revealed that a diagnosis of pre-diabetes had motivated him to lose 13 kilos, the headline grabber was the fact that he’d given up sugar. Less widely reported was his other change of habit – more exercise.
Yes, it’s smart to go easy on sugar and it’s a no brainer that we should ditch diets based on foods overloaded with sugar, salt and bad fat. But implying that an overload of sugary food alone is why the body struggles to keep blood glucose under control is misleading.
There’s one good thing about pre-diabetes though: it’s a warning. There’s still time to make lifestyle changes that can help bring blood sugar back to normal before you’re stuck with diabetes. But blood glucose rises silently and the only way to know you’re drifting into the danger zone is a blood test, says Cohen who suggests that people over 40 use the AusDrisk Test, a free online tool that calculates your risk of Type 2 diabetes. Women with a history of gestational diabetes or polycystic ovary syndrome should also have regular blood testing for diabetes, he adds.