The current ‘debate’ about sugar and health descended into farce last Sunday night with the broadcast of a 60 Minutes program in which it was suggested that sugar ‘is as addictive as the hardest drugs’.
The argument behind this claim rests on the supposedly similar responses in the brain to sugar and cocaine. The brain contains a reward centre that is designed encourage survival behaviours, such as eating and sex. If these things were not pleasurable humans would not eat or reproduce and the species would disappear. Foods, sugar, fat and especially the combination of sugar and fat trigger this reward centre, and so does cocaine. So, with a huge leap of faith and imagination, sugar equals cocaine.
An American neuropsychologist on the program claimed that … sugar kills way more people than any psychoactive drug – an absurd claim that simply cannot be supported scientifically. I have never seen any credible scientific study that attempted to associate sugar intake with increased risk of death. Scientists have gone to great lengths to investigate the role of dietary factors in preventable disease but sugar intake simply does not feature in their calculations. In susceptible people, the risk for tooth decay may increase with the consumption of carbohydrates i.e. added sugars, natural sugars in fruits and even breast milk, and starch. But that’s it – that’s the health risk posed by sugar. Eating sugar does not kill people.
New research has strengthened the case that the glycaemic index of carbohydrate-rich foods affects the risk for cardiovascular disease and is a useful tool in weight management. But Australian health authorities are in denial, refusing to even look at the data.
Four decades ago nutritionists were taught that complex carbohydrate (starch) was desirable as it was slowly digested and absorbed, which led to a gradual rise in blood glucose and this was considered to be a good thing. In contrast, simple sugars were thought to be rapidly broken down and absorbed, giving a high blood glucose response. Although logical enough, it wasn’t true.
When the blood glucose-raising effects of various foods were actually measured it was found that some starchy foods, such as potato and rice, produced very rapid increases in blood glucose to high levels – higher than that of table sugar. Use of the terms simple sugars and complex carbohydrate is now discouraged by the World Health Organization.
Professor Robert Lustig argues that sugar, or fructose in particular, is ‘toxic’ and increases the risk for obesity and the metabolic syndrome. He paints a simple picture – glucose is good, fructose is bad – based on the differing metabolism of these sugars. He claims that fructose is similar to alcohol and should be taxed accordingly. Professor Lustig certainly has our attention but do his claims stack up?
In last week’s blog I looked at the reviews on sugar and health conducted by the European Food Safety Authority and the US Institute of Medicine. They both found that sugar is fairly benign with respect to chronic disease but can lower the nutrient density of the diet when intake is high, though this depends on which sugar-rich foods and drinks are consumed.
Professor Robert Lustig from the University of California has a very different view.
In a few short years sugar has replaced fat as the main dietary villain and the lay media is full of horror stories about the role that sugar plays in chronic disease. Scientific reviews of the role of sugar, health and disease by leading nutrition agencies tell a different story, finding sugar is fairly benign with respect to chronic disease. However, dietary quality may be affected at very high intakes of sugar.
Who are the experts?
During the last seven years there have been two comprehensive assessments of the role that sugar plays in health, one in Europe and one in the United States. One review was conducted by the European Food Safety Authority (EFSA) and published in 2010. In relation to nutrition, EFSA provides the most up-to-date and comprehensive scientific advice to support EU policy makers in their decision making process in the field of nutrition. EFSA’s advice on nutrient intakes provides an important evidence base to underpin nutritional policies, the setting of diet-related public health targets and the development of consumer information and educational programmes on healthy diets.