Consumption of sugar-sweetened beverages – but not beverages sweetened with aspartame – is associated with suppression of cortisol and stress responses in the brain in new research published in the Journal of Clinical Endocrinology & Metabolism.

The primary outcome of this parallel-arm, double-masked diet intervention study was salivary cortisol and regional brain responses to the Montreal Imaging Stress Task after consumption of sugar- or aspartame-sweetened beverages. Nineteen women aged 18–40 with a body mass index ranging from 20–34kg/m2 participated in the study, where over a 12-day outpatient phase the women drank one of the assigned beverages at breakfast, lunch, and dinner and consumed a usual diet. For 3.5 days prior to and after the intervention period, the women resided at the UC Davis Clinical and Translational Science Center’s Clinical Research Center and consumed a standardized, low-sugar baseline diet and underwent function MRI (fMRI) screening after performing math tests to assess the brain’s response to stress. Saliva samples were also provided to measure cortisol levels.

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Sugar consumption was linked to significantly higher activity in the left hippocampus and reduced stress-induced cortisol vs. aspartame consumption. The sugar arm also had a lower reactivity to naltrexone, significantly lower nausea, and a trend towards lower cortisol.

These results provide new insight into the relationship between sugar consumption and cortisol reactivity to stress, and how habitual consumption of sugar may relieve psychological or emotional stress, stated lead author Kevin D. Laugero, PhD. However, overconsumption of sugar can have significant negative health effects, including obesity.

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