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High-Normal Blood Sugar Harms Brain

In September 2012, Australian researchers published findings showing blood glucose at the high end of normal resulted in significant brain shrinkage.1,2 The shrinkage occurred in regions of the brain (hippocampus and amygdala) involved in memory and other critical functions. Atrophy (shrinkage) in these brain areas worsens memory.1,2

For this study, neuroscientists at Australian National University in Canberra studied 249 people in their early 60s. Each of them had blood sugar levels in the normal range. The study subjects’ brains were scanned at the beginning of the study, and again four years later.

Comparing the before and after images, the researchers found significant brain shrinkage among those whose blood sugar levels were high but still below the World Health Organization’s threshold for prediabetes (fasting glucose under 110 mg/dL). The researchers report that these high- normal levels may account for a 6% to 10% decrease in the volume of the hippocampus and amygdala.

The lead researcher stated, “It is this chronic exposure to high glucose levels that is more likely to lead to poorer brain health.” He cautioned that these findings should not be taken “lightly,” as the association between high- normal blood sugar and brain shrinkage was “robust.”1,2

This reinforces the need for people to suppress excess blood glucose

Fasting and post-meal glucose goals to aim for:

Fasting glucose: under 80 mg/dL

Post-meal glucose: under 120 mg/dL


5 Replies

We in the UK are advised 4-6 mmol/l for fasting, which is roughly 72-108 mg/dl, but 5.5 is an indication that the metabolism is being stressed/struggling to cope with the glycaemic load (metabolic syndrome).


This seems confusing... in a number of literature the ideal sugar level (fbs) is said to be no less than 80. Even in Glucometers, the lower than 80 fbs is already a danger of Hypoglycemia... The first time I was diagnosed as diabetic and when during my blood count I went to 70... the doctor was almost frantic and insisted that I eat soonest.. but I understand that new studies do offer new insights.... oh well...


On my box of glucometer, low blood glucose range is 20-69 mg/dl but I do personally also feel hypoglycemic when I got BS level of 83 mg/dl. Once it was 63 mg/dl and it was really frightening to have hypoglycemic symptoms...it is like almost dying...However, I am not getting any hypoglycemic episodes once I stopped sulphonyl urea drug...glimepride

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Hi Ashka9

This is Rias. I live in South Africa. I was diagnosed with diabetes type 2 in 1998. I am using Metformin to control my blood sugar level. My blood sugar level is very high during fasting period, especially in the morning before eating anything. I don't want to use drugs because of its side-effects. Advise me which herbs to use in order to control blood sugar level.


Take Gynmema extract 400 mg in a day before meals. Alternatively, you can take Diabecon DS tablet from Himalaya Herbals one each morning and night. Diabecon tab contains about 34 herbs which acts synergistically and also contains Gymnema. It reduces fasting blood sugar levels and post pandrial blood sugar levels as well. Taking Karela tablets twice a day also helps.

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