September 2010 newsletter: feature — How sweet is it?

Beware the label ‘sugar free’

If you have diabetes there’s a high chance you count carbs. Reading labels is a great habit, but while there’s often loads of information on them, sometimes labels are not all that they seem. Diabetics might see the label on a packet of food that says ‘sugar free’ and think they can have a snack that won’t send their blood sugars rocketing. But appearances can be deceptive.

It seems like more and more labels straddle the demands of listing their contents with a demand from the marketing teams to ‘massage the truth’ by making claims about the contents that can be misleading. With diabetes – both Type 1 and Type 2 on the rise, and with diet a matter of daily conversation for many of us, we need to warn you that the term ‘sugar free’ can mean anything but when it comes to managing your condition. Sugar free it may be, but that product could have a considerable affect on your blood sugar levels.

The following article is by Dr Nina Bailey, a nutrition scientist who concentrates on the role of dietary health and nutritional intervention in disease. She looks at the issues raised by the labelling of sugars in food products and how sugars differ from carbohydrates.

“Use of the nutrition claim ‘sugar free’ is controlled by European Union (EU) legislation (EU Regulation 1924/2006); to make such a claim, there must be no more than 0.5 g of sugars per 100 g or 100 ml of product.  However, while the label of a product may suggest it is sugar free, the actual carbohydrate content within the product may be dominant over the protein and fat content.   This raises the question: if all carbohydrate is sugar, can a product’s claim of ‘sugar free’ be misleading and would such a product impact negatively on blood sugar levels? To answer this question we must first have a basic understanding of what carbohydrate is, and the role it plays within our diet.  Carbohydrates are the main energy source in the human diet, and should make up around 50-60% of an individual’s daily calorie intake. However, the impact that carbohydrate makes on blood sugar levels depends primarily on the structure of the carbohydrate in question.

Carbohydrates can be classified into glycaemic carbohydrates, which are digested and absorbed in the small intestine, and non-glycaemic carbohydrates, which enter the large intestine. It is the glycaemic carbohydrates that are of particular significance to blood glucose levels and the subsequent effect on insulin secretion. Sucrose, or ordinary table sugar, is a disaccharide made up of one molecule of glucose and one molecule of fructose, and is a common ingredient in many processed and ’junk’ foods.  Sucrose is easily digested, and both glucose and fructose are rapidly absorbed into the bloodstream in the small intestine.  Consequently, consumption of foods high in sugar, and classed as ‘simple carbohydrates’, results in high blood glucose levels.

In contrast, more complex carbohydrate such as dietary starch (the predominant carbohydrate found in potatoes and pasta for example), is made up of many glucose molecules joined together to form amylose (200-2,000 glucose molecules) and amylopectin (branched chains of 10,000- 1 million glucose molecules). The fact that amylose and amylopectin have to undergo a more complex form of chemical digestion means that the glucose released from these starches or ‘complex carbohydrates’ is much slower.  So while all carbohydrate is sugar, not all carbohydrate has the same effect on blood glucose levels, which should ideally range between 4 and 7mmol/l and no more than 10mmol/l after the consumption of food.

Consistently high blood glucose levels, through consumption of foods high in simple sugars, is known to have detrimental effects on insulin sensitivity – therefore it can be a contributory cause of Type 2 diabetes. The glycaemic index (GI) is a tool used to classify carbohydrate and carbohydrate-containing foods on their impact on blood glucose levels. Foods that are absorbed and digested slowly are considered to be of a low GI, giving rise to lower but longer elevations in blood glucose levels and are considered to be health positive. In contrast, high GI food products (of which glucose is the highest) including those that have been highly processed and fibre depleted, are rapidly digestible, energy dense, and exert negative effects on glucose release and therefore on insulin sensitivity.

For a product to be classed as ‘sugar free’ implies that any remaining carbohydrate will be in a more complex form and therefore will release glucose at a slower rate than an equal product containing simple sugars.    Indeed, it is now generally accepted that consuming foods rated as low GI, such as whole grains, may reduce chronic disease risk including diabetes, metabolic syndrome, inflammatory conditions, cardiovascular disease and even some types of cancer through favourable effects on blood glucose levels and insulin sensitivity.

Ideally, anyone who is concerned about raised sugar levels should avoid heavily refined and processed foods, as these are more likely to be rich in simple sugars and low or lacking in complex carbohydrates. In contrast, the primary ‘sugar’ found in fruit is fructose, which, unlike glucose, does not stimulate insulin secretion. If you are looking for a sweet treat, fruit really is nature’s answer to this craving.”

Editor’s comment: They’re not called sweets for nothing. If it looks like a sweet and tastes like a sweet, it’s probably full of sugar. It might not be a marketing ploy or deliberately misleading, but I’ve been caught out before, and living with Type 1 could do without the confusion. Those of us trying to watch their weight might do well to take note as well. This is true not only for sweets, but also some medicines (such as cough syrups and lozenges) which also state ‘sugar free’ – read the label and read the carbohydrate content and make your insulin dose calculations on the carb value not that of the sugars.

What do you think? Please send your comments to sue.marshall@desangstaging.wpengine.com

With thanks to Dr Nina Bailey www.drninabailey.com

Further reading: www.food.gov.uk/foodlabelling/ and

http://www.glycemicindex.com/

Dr Bailey advises for Igennus nutrition which has a microsite on diabetes at  http://igennus-hn.com/health-benefits/diabetes/

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