The effects of sugar are not as restricted as we might think; rather, they are apparently weighty on our brain too. A new study suggests that sugary drinks might be as bad as stress and abuse are to brain cells. The paper is published in Frontiers in Molecular Neuroscience.
Extreme stress and abuse are known to have detrimental impacts on the brain regions involving cognition and emotional behaviour. Trauma faced in childhood is linked with increased levels of the major stress hormone called cortisol. Such experiences in early life are also associated with greater risks of having mental disorders in later years. Now, imagine a version of these effects caused by sugar.
The researchers of the new study aimed at determining whether the intake of sugary drinks in high amounts could exacerbate the repercussions of early life stress on the brain by studying female rats specially because females tend to feel the effects more.
To reproduce the effects of life trauma or abuse, a group of rats (half of the total) were put under conditions of limited nesting material when they were two-day-old until their ninth day, after which they were placed to normal bedding till they weaned. This was meant to modify maternal behaviour and to increase anxiety in the children in the later years of their life. Furthermore, half of them were exposed to unrestricted access to low-fat chow and water while the sisters were given chow, water and a 25% sugar solution. They were divided into 4 groups: control (no stress), control rats drinking sugar solution, rats exposed to stress, and rats exposed to stress who drank sugar.
It was found that those exposed to early life stress were smaller when they were weaned. The difference, however, disappeared over time. Also, rats eating sugar in both groups would eat more calories during the experiment.
When the rats reached 15 weeks old, their brains were examined. The hippocampus region of the brain which is linked with memory and stress was analysed and similar changes in the hippocampus were found in the group of rats exposed to stress which drank sugar as well in those stressed but not having drunk sugar: early life stress or sugar drinking caused a decreased expression of the receptor of cortisol which might affect recovery from stress. Sugar and stress were also found to decrease the expression of other genes important for the growth of nerves while the combination of high sugar intake and stress did not cause further changes in the hippocampus.
It thus appears that drinking sugar at a young age might be affecting brain development. This finding is yet to be tested tough.
In a world context where people are increasingly consuming sugary drinks, even young children, the findings are worrying. The brain circuits governing stress responses and feeding are conserved across species. Therefore, if the same happens to the human brain as that of the rats, we might want to give serious thought to the consumption of sugary drinks.