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The great carbohydrate debate

Those of you who read my last blog may recall that one of my subjects was the Olympic Games and how we can create opportunities with our patients to raise ths issue of diet and physical activity.

I have just been reading my September copy of the Insulin Dependent Diabetes Trust. In this edition, one article, which first appeared in the Times on 17 July this year, might seem controversial. Why is it controversial, you may ask? Well, it highlights the high carbohydrate diet versus low carbohydrate diet question.

The DAFNE (Dose Adjustment for Normal Eating) course teaches that, those with type 1 diabetes can eat as much as they want, as long as they count their carbohydrate intake and match it with the appropriate dose of insulin.

An American doctor suggested to someone with type 1 diabetes that he should cut down on carbs as much as possible rather than eating what he liked (including carbohydrates). Following this advice caused this patient to reduce his insulin dose to a quarter of his normal dose, his blood glucose control improved amazingly, he lost 33lbs in weight and no change to his cholesterol levels.

What would be your thoughts on hearing this?

The article is then followed by a discussion, where it is suggested that eating a high quantity of carbs means more insulin is needed to control blood sugars in those with type 1 diabetes.

On the other hand, if you cut your carb intake, then insulin doses will decrease and so will chances of having a hypoglycaemic attack be reduced; remember, it is insulin that causes hypos, not diabetes itself.

If type 2 diabetes is under discussion, then from the start, the body is struggling to produce enough insulin to metabolise carbohydrates, so why eat more and then make the situation worse?

Some experts might argue that low carb/high fat diet could increase the risk of heart attack. In fact there is no need to increase fat, and even if that did happen, there has been research which says that this can improve blood glucose and cholesterol levels and decrease the required dosage of insulin.

What is your understanding of what is a healthy diet for those with diabetes, particularly when treated with insulin? Do you endeavour to tell your patients where the excess glucose in their bodies comes from, or how it is metabolised? What do you think of the idea that research into diet and its impact on diabetes, could profoundly change the way those with and without diabetes manage their food intake?

It is so easy to follow the crowd and not check that guidance we receive is in fact evidence based. Sometimes guidance is driven by cost as much as a treatment being the most effective.

We, as nurses have a duty of care to our patients and surely that means we should be sure of the treatment and advice that we give to our patients, that it is evidence-based and that any changes are for their best. We must not be tempted to do what everyone else does, which may have little if any evidence base.

Take the example of using sulphonylureas, a relatively inexpensive drug used to control blood glucose levels. Why do we still use it so much when after just a few years it cannot force very little more insulin to be produced by the Islet cells in the pancreas? There are other limitations as well, and these include caution with the elderly due to hypoglycaemia risk and often weight gain in any person with type 2.

Personally, I prefer to prescribe sulphonylureas, when a patient really cannot tolerate metformin, or is in fact not the typical type 2 patient, but is in fact thin and so associated weight gain is not a problem for them. What about you, or do you take the easy route?

An endocrinologist I worked with a few years ago stated quite clearly at a meeting that guidelines, such as those produced by NICE, are just that, guidelines, and they must not inhibit us from using our own clinical judgement.