Blood Sugar…shrinks the brain?

Check out this week old study! Subjects had their brain volume examined through MRI four years ago to evaluate changes that may occur prospectively.

“The aim of this study was…to investigate in cognitively healthy individuals, who did not have T2D, whether higher fasting plasma glucose levels falling in the normal range as defined by the World Health Organization were associated with declines in hippocampal and amygdalar volumes.”

The results?

Plasma glucose levels were found to be significantly associated with hippocampal and amygdalar atrophy and accounted for 6%–10% in volume change after controlling for age, sex, body mass index, hypertension, alcohol, and smoking.

High plasma glucose levels within the normal range (<6.1 mmol/L) were associated with greater atrophy of structures relevant to aging and neurodegenerative processes, the hippocampus and amygdala. These findings suggest that even in the subclinical range and in the absence of diabetes, monitoring and management of plasma glucose levels could have an impact on cerebral health. If replicated, this finding may contribute to a reevaluation of the concept of normal blood glucose levels and the definition of diabetes

Pretty fascinating stuff. Keep in mind that diabetic/prediabetic/normo ranges for blood glucose are usually changing. They used WHO guidelines in this study but a range of <6.1 nmol/L is usually the beginnings of pre diabetes for many other guidelines.

From the mayo clinic – Fasting blood sugar test. A blood sample will be taken after an overnight fast. A fasting blood sugar level less than 100 mg/dL (5.6 mmol/L) is normal. A fasting blood sugar level from 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is considered prediabetes

However, the study took this into consideration:

…subanalyses using even tighter inclusion criteria for fasting glucose (<5.6 mmol/L) and for BMI (<25 kg/m2) produced essentially identical findings or, in the case of BMI, slightly stronger findings. This result suggests that the effect of plasma glucose on cerebral structural integrity is not restricted to the upper normal range.

Update: Another study this week showing the differences between Teens with Metabolic syndrome and those that don’t in regards to cognitive function. As expected, cognitive scores were lower in the teens with metabolic syndrome.


Higher normal fasting plasma glucose is associated with hippocampal atrophyThe PATH StudyNicolas Cherbuin, PhD, Perminder Sachdev, MD, PhD, FRANZCP and Kaarin J. Anstey, PhD. Neurology September 4, 2012 vol. 79 no. 10 1019-1026

Obesity and Metabolic Syndrome and Functional and Structural Brain Impairments in AdolescencePo Lai Yau, PhDa, Mary Grace Castro, BSa, Adrian Tagania, Wai Hon Tsui, MSa, and Antonio Convit, MD doi: 10.1542/peds.2012-0324



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