
“Sugar addiction” appears to be the latest honey pot target for the sweet and innocent. We felt it necessary to have a look at the evidence – both recent and passed – and give objective commentary for those who wish to be better informed. Just in case you were worried, this blog won’t sugar-coat the facts (oh! For the pun of it). At the beginning of March 2014, the World Health Organization (WHO) proposed a new set of potential guidelines that maintained the previous recommendation that no more than 10% of one’s daily caloric intake should come from sugars. However what the WHO’s new guidelines also introduced, was recommendation that further reducing sugar consumption to less than 5% of the daily caloric intake is advised for “additional benefits.” To put this into practical perspective, 5 – 10% of a 2 000 calorie diet is 100 – 200 calories, or 25-50g of sugar per day. One 340ml can of coke contains 8-10 teaspoons of sugar or 40-50g, so it is easy to see how quickly these targets can be breached. We live in a world where obesity rates have almost doubled since 1980 and total energy intake has increased by 150-300 calories per day with approximately 50% of these calories come from sugar sweetened beverages. Given these considerations it is imperative that a multifaceted approach is taken to address these issues, one of which is most certainly, to reduce energy intake from added sugars. This is undisputed. The debate arises however, when the concept of “sugar addiction” is thrown into the mix, as many argue it is not yet supported by scientific evidence. The “pleasure centre” of the brain is made up of the ventral tegmental area and the nucleus accumbens. These limbic structures are central to the hedonic pathway that motivates the rewards of food intake. The palatability of food available can override normal satiety signals and motivate for energy intake, irrespective of energy need. When a sugar-containing infusion is injected directly into these areas, dopamine and opioid neurotransmission is altered which in turn increases food intake. However, both sweet and high fat foods mobilize opioids and dopamine within the nucleus accumbens and can establish hard-wired pathways for craving in these areas. Stress has also been shown to cause chronic amygdala activation which increases cortisol secretion and subsequently promotes palatable food consumption as a form of self-medication. (Johnson et al, 2009) A lot of medical and complicated jargon, but bottom line there is an element of “comfort eating”, specifically with regards to the reward and pleasure response to fats and sugars. Professor David Benton is an expert in the field and a long standing proponent of the view that adding the concept of “sugar addiction” to an already complex problem, makes it even more, unnecessarily, complicated. He argues that looking at the concept of reward, the following all stimulate reward mechanism pathways in the brain:
A wide range of pleasant phenomena can cause dopamine release and so the biological reaction to sugar cannot by itself lead to the conclusion that its consumption is addictive. Dr Dominic M Dwyer from the School of Psychology at Cardiff University stated: “Human-based research on the effects of obesity and overconsumption of sugar rich foods on reward systems and the overlap with drug abuse is in its infancy.” He went on to assert that 90% of obese individuals do not show addiction-like responses to foods and rather, addiction-like behaviours might be more closely tied to binge eating disorders. That said, he did agree that other research has shown that sugars are powerful reinforcers in supporting food-preference learning and so, even outside their addiction-like potential, sugars can have a significant effect on obesogenic eating patterns. Prof David Nutt, Chair of the Independent Scientific Committee on Drugs (ISCD) and Head of the Department of Neuropsychopharmacology and Molecular Imaging at Imperial College London, said: “There is not currently scientific evidence that sugar is addictive, though it is well known that sugar has psychological effects, including producing pleasure.” He added that refined sugar gets into the brain faster than sugar from starch and that it is known from studies on narcotics that the faster substances get into the brain, the bigger the ‘hit’.” Prof Suzanne Dickson is a Professor of Physiology at The Sahlgrenska Academy at the University of Gothenburg where she coordinates the NeuroFAST project. This project is looking, amongst other things, at the question of food addiction. She said: “The bottom line is that we find very little evidence that any food, ingredient, combination or additive (with the exception of caffeine) has addictive properties. “ She did go on to discuss the seemingly unquestionable fact that some individuals display behaviours towards food that are consistent with addiction, especially those with binge eating disorder. She believes there is a great need to explore additional avenues – including genetic susceptibility, lifestyle bahaviours and stress coping mechanisms. Lastly, Prof Barry Everitt, Professor of Behavioural Neuroscience at the University of Cambridge, had this to say on the topic of sugar addiction: “The issue of whether or not sugar is addictive is complex as it is obvious that sugar (and fats) are reinforcing and that they do indeed result in activation of the dopamine system in the reward system in the brain. However, drugs like cocaine activate dopamine release far more than food reinforcers do.” He concluded by saying that the suggestion that food is addictive sends out a misleading and unhelpful message, “even though we could all do with cutting down on or eliminating sugar intake”. Sugar addiction is an interesting topic evidently with much room still for research. Strong trends that repeatedly emerge are that we are consuming too much sugar on a daily basis and that these dietary habits can certainly form reward patterns and comfort cycles that are difficult to break. Perhaps we should not yet use the word “addiction” to describe our relationship with sugar but we should be aware of just how much we are consuming daily and be sensitive and cautious to how and when we use sugar as a comfort-crutch to deal with daily challenges. As I started, I leave you with a joke…When I reduced the sugar content in my diet, I really missed it! After all those years apart of my life, we glu-close. Useful links and references:
http://www.neurofast.eu/consensus/
http://www.eatright.org/About/Content.aspx?id=8363
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