Kerin O’Dea writes:
The European Food and Safety Agency (EFSA) has just approved health claims for fructose-sweetened products, in a move that has astonished scientists around the world.
Food and drink manufacturers can now claim that their products are healthier if they replace at least 30% of their glucose or sucrose with fructose.
The rationale provided by the EFSA for the decision is that fructose has a low glycemic index (GI). The glycemic index of a particular food is a measure of the rise in blood glucose levels in response to 50 grams of carbohydrate in that food.
This glucose response drives the subsequent insulin response, and insulin is the major hormone driving fat accumulation. That’s the link with obesity.
But it’s not really as simple as that. Just because a food has a low glycemic index doesn’t mean it’s healthy or that you can eat as much of it as you want.
Processed foods containing fat (such as ice-cream, chocolate, and potato crisps) have a low glycemic index because fat slows gastric emptying (the rate at which food enters the small intestine from the stomach). But most of us would recognise they are not the ideal foods to eat when you want to lose weight.
Fructose has a low glycemic index, which is not surprising since it’s not glucose (recall that glycemic index measures the rise in blood glucose levels). But that doesn’t mean it’s not potentially problematic.
Fructose and glucose are handled very differently by the body. Whereas glucose is used by most tissues as a source of energy, fructose is taken up almost entirely by the liver.
When we are eating more than we need, fructose is converted very efficiently by the liver into fat. Just like excessive alcohol consumption, this can cause fatty liver (non-alcoholic fatty liver), which is now very common among people who are overweight and obese.
Left unchecked, fatty liver can lead to cirrhosis and liver failure. It also contributes to weight gain generally.
Excess consumption of glucose (in the form of starchy foods) can certainly contribute to weight gain, but not fatty liver.
Excessive consumption of fructose (more so than glucose) exacerbates insulin resistance and the metabolic syndrome – and thereby greatly increases the risk of type 2 diabetes and cardiovascular disease.
It’s important to note that dietary fructose is not a problem if you’re lean and fit, and not over-eating. Under those circumstances, the fructose will be metabolised as an energy source.
The major sources of glucose are starches (polymers of glucose) and sucrose (which is comprised of one molecule of glucose and one of fructose).
Our major source of fructose in Australia is sucrose. In the United States, high fructose corn syrup is now a major source.
While there’s also fructose in fruit, it’s in a diluted form and present with a range of other healthy nutrients and fibre. And health claims are overwhelming applied to highly-processed foods (think of the last time you saw a health claim on an apple).
But why would the processed food industry want to be able to make health claims for fructose?
Fructose is much sweeter than glucose and significantly sweeter than sucrose. The food industry has conducted very sophisticated research on what stimulates food consumption (the “bliss point”), and found that, together with fat and salt, sweetness is one of the major drivers of excess food intake.
So, sweetness is very good for business.
And interestingly, when we drink calories, particularly watery calories as in soft drinks or alcohol (as opposed to soup), our body does not recognise them as such; it’s as if we were drinking water.
Caloric drinks are particularly problematic because they’re added on to what we voluntarily eat.
The European Union’s approach to food regulation, then, is very reductionist. The EFSA has taken one short-term impact of a food component (the glycemic index) to justify a health claim for fructose, and ignored all the science that indicates its adverse impacts on long-term health in relation to over-consumption, weight gain, diabetes, heart disease and liver disease.
This is yet another victory for the powerful processed food and beverage lobbies over advocates for public health.
** Kerin O’Dea is Professor of Population Health and Nutrition at University of South Australia
** Kerin O’Dea receives funding from the National Health and Medical Research Council and the Australian Research Council