A study, published in the Journal of Clinical Endocrinology and Metabolism, found that levels of the stress hormone cortisol were lower in women after a two-week period of drinking sucrose- than aspartame- sweetened drinks when they performed a set of maths challenges.
Using MRI scans they also found that sugar inhibited stress-induced activity in the hippocampus.
“These experimental findings support a (…) feedback pathway that is affected by sugar and may make some people under stress more hooked on sugar and possibly more vulnerable to obesity and its related conditions,” said the study.
The authors said that during times of stress around 80% of people report eating sweet or high calorie food, and that this was the first evidence that sugar - but not aspartame - was actually effective in relieving stress in humans.
However Katherine Jenner from Action on Sugar questioned the soundness of the authors’ conclusions.
“Eating lots of sugar certainly won’t help your stress levels in the long term - eating a healthy diet will have a positive effect on both your physical, and mental health,” she said.
“The current high levels of sugar the UK population are not because everyone is ‘stress eating’, but because sugar, in various disguises, is hidden in most of our everyday foods."
She also said that a reduction in both sucrose and sweeteners was needed in order to reduce expectations of sweetness.
“It is very important that all reformulation programmes reduce both the sugars and the sweetness of the products, for the best effect.”
An over zealous interpretation?
Graham MacGregor, professor of cardiovascular medicine at Queen Mary University of London and chairman of Action on Sugar also warned that the researchers may have over-interpreted their results.
The cortisol levels in the artificial sweetener group were higher to begin with meaning that while absolute levels were different, the drop in cortisol was similar he said.
He called for larger studies which took into account initial cortisol readings – but added that the overall message that should be taken from the study was to reduce sugar consumption
Start with the industry - government will follow
He pointed to the success of salt reduction in the UK where average UK salt intake is around 15% lower than before a national campaign to cut consumption, with salt content in some food categories 40-50% lower.
“A five percent reduction year on year - not only for sugar but artificial sweeteners too – [is needed]. People’s sweet taste receptors adjust and they don’t notice.”
But MacGregor said that change was unlikely to come from health policy-makers and that focus should be on industry: “We need to start with companies and then the government will follow.”
He said he was optimistic that that within two to three months there would be a development in this direction, although he declined to give more details.
Source: The Journal of Clinical Endocrinology and Metabolism
"Excessive Sugar Consumption May Be a Difficult Habit to Break: A View from the Brain and Body"
Published online ahead of print: 16 April 2015 doi: 10.1210/jc.2014-4353
Authors: M. S. Tryon, K. D. Laugero et al.