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Sugar may be as damaging to the brain as extreme stress or abuse

   February 17, 2016 12:24pm
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   The changes we observed to the region of the brain that controls
   emotional behaviour and cognitive function were more extensive than
   those caused by extreme early life stress.

   It is known that adverse experiences early in life, such as extreme
   stress or abuse, increase the risk of poor mental health and
   psychiatric disorders later in life.

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   bereavement; natural disasters; physical, sexual and emotional abuse;
   domestic violence and being a victim of crime) a child is exposed to is
   associated with elevated concentrations of the major stress hormone,
   cortisol.

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   WHAT WE FOUND

   Looking at rats, we examined whether the impact of early life stress on
   the brain was exacerbated by drinking high volumes of sugary drinks
   after weaning. As females are more likely to experience adverse life
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   chow and water to drink, while their sisters were given chow, water and
   a 25 per cent sugar solution that they could choose to drink. Animals
   exposed to early life stress were smaller at weaning, but this
   difference disappeared over time. Rats consuming sugar in both groups
   (control and stress) ate more calories over the experiment.

   The rats were followed until they were 15 weeks old, and then their
   brains were examined. As we know that early life stress can impact
   mental health and function, we examined a part of the brain called the
   hippocampus, which is important for both memory and stress. Four groups
   of rats were studied — control (no stress), control rats drinking
   sugar, rats exposed to stress, and rats exposed to stress who drank
   sugar.

   We found that chronic consumption of sugar in rats who were not
   stressed produced similar changes in the hippocampus as seen in the
   rats who were stressed but not drinking sugar. Early life stress
   exposure or sugar drinking led to lower expression of the receptor that
   binds the major stress hormone cortisol, which may affect the ability
   to recover from exposure to a stressful situation.

   Another gene that is important for the growth of nerves, Neurod1, was
   also reduced by both sugar and stress. Other genes important for the
   growth of nerves were investigated, and just drinking sugar from a
   young age was sufficient to reduce them.
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   although further work is required to test this.

   In this study, combining sugar intake and early life stress did not
   produce further changes in the hippocampus, but whether this remains
   the case over time is unclear.
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   reducing the consumption of sugar across the community is important.

   The fact that drinking sugar or exposure to early life stress reduced
   the expression of genes critical for brain development and growth is of
   great concern. While it is impossible to perform such studies in
   humans, the brain circuits controlling stress responses and feeding are
   conserved across species.