Can “Normal” Blood Sugar Levels Shrink Your Brain?

Can “Normal” Blood Sugar Levels Shrink Your Brain?

In This Article

How is Your Blood Sugar? 

lifespa image, blood sugar, spoonful of sugar and cubes on wood table

Are sugary treats your guilty pleasure? The information in this article could make you swear off sugar once and for all.  


High glucose levels may be the smoking gun for compromised brain health. In a study conducted at The Australian National University, 249 volunteers in their early 60s with “normal” blood sugars were given brain scans. 

When researches compared images over four years, there was significant decrease in brain volume, or brain shrinkage, in folks whose blood sugars were high but still in the normal range as set by the World Health Organization (WHO). Volunteers with high-normal glucose levels (fasting glucose below 110 mg/dL) experienced reduced brain size by as much as 10%!1 

High-Normal Blood Sugar Linked to Brain Shrinkage 

The above study found decreased volume and atrophy in both the hippocampus, which controls long- and short-term memory, and the amygdala, responsible for emotional health. 

High-normal blood sugars in the blood can glycate, or clump together, sticking to proteins in the blood, becoming advanced glycation end products (AGEs). Studies show AGEs may be the smoking gun for one’s chances of developing liver, kidney, heart, or cognitive issues over time.2-5 

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Use LifeSpa's Sugar Destroyer to block the uptake of sugar in the moyh and intestines. 

Test Your Blood Sugar 

The best way to determine if you have higher glycation levels than normal is with a test called a hemoglobin A1c test (HbA1c). The A1c test can determine a three-month average of blood sugar levels by calculating the amount of glycated hemoglobin molecules present. A high-normal glucose level is 5.6%; the goal should be a number at or less than 5.3%. While this test is very common, you may want to ask your doctor for it as an alternative screening for blood sugar. 

blood sugar test image 1

The standard test for blood sugar is a fasting glucose test, typically taken first thing in the morning after 8-12 hours of fasting. Today, normal levels in the US are set between 80 and 99 mg/dL. I suggest my patients to have the goal of keeping their fasting glucose levels between 70-85 mg/dL. 

In one study, folks who had blood sugar levels just above 85mg/dL had a 40% increased risk of fatality from cardiovascular disease.6,7 

In another study, published in the New England Journal of Medicine, folks who had blood sugar levels between 90-95mg/dL—still in normal range—had an increased risk of dementia.8  

b12 brain on treadmill image

High-normal blood sugar and prediabetes are the silent epidemic of our time. Serious effort is required to reverse course and reestablish healthy blood sugar levels to avoid any long-term consequences.  

If you want to test your blood sugar at home, check out our blood sugar self-testing device.
We recommend "Blood Sugar Secrets for Health and Longevity eBook":

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Dr. John


  6. DouillardJohn. Blood Sugar Secrets for Health and Longevity. 


7 thoughts on “Can “Normal” Blood Sugar Levels Shrink Your Brain?”

  1. Wouldn’t the depletion of Chromium Picolinate (CP) from the brain also contribute the brain shrinkage? As you know, the body needs CP to digest sugar and CP is stripped from refined sugar but fully present in sugar’s natural, unrefined form. My understanding is that the only place the body stores CP is in the brain as it is necessary for healthy brain function. However, it’s also necessary to digest sugar and if the CP is not present in the sugar being digested then the body will strip it from the brain–since digesting food is vital. Thoughts?

    • That’s one more reason to eat brewer’s yeast, which contains cp. Rather than lowering the bloodsugar away with apple skins or something. I don’t want to eat more yeast though. But there’s nowhere the sugar can go if you’re sedentary, except for the brain that consumes a lot. I’ve always been told that sugar is fuel for a space shuttle.

  2. As a Type 1 diabetic this news has been distressing because I should not and cannot safely achieve that A1C. So what protects me from the frequent highs? What heals the cells from the daily damage?

    • Hi Karen,

      Generally fresh fruit is best in season and whole (not peeled) as there are constituents that mitigate blood sugar in the skin of most skin edible fruits.

      LifeSpa Staff


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