Sadly, type-2 diabetes is more prevalent than ever in our society due to increasing rates of obesity, inactivity, stress, as well as an aging population. It’s long been known that diabetes increases your risk of stroke, kidney failure, vascular damage, and heart disease.1

But science shows that’s just the tip of the iceberg…

Recent research suggests a strong link between type-2 diabetes and Alzheimer’s disease. In fact, some people even refer to the memory-robbing disease as type-3 diabetes. Let’s take a closer look at what researchers have discovered…

It might surprise you to know that having diabetes or pre-diabetes is the second biggest risk factor for Alzheimer’s disease, according to the American Diabetes Association.2 (The first is your age.)

Recent research reinforces the dangers of high blood sugar to your memory. In fact, one new study examines the association between the age of type-2 diabetes onset and subsequent dementia, while another shows the impact that chronically high blood sugar has on working memory.

The Connection Between High Blood Sugar and Memory Loss

A team of neuroscientists at the University of Nevada, Las Vegas (UNLV) have been exploring the link between high blood sugar and Alzheimer’s disease for more than six years.

“Diabetes is a major risk factor for developing Alzheimer’s disease, but it is not clear why,” says James Hyman, associate professor of psychology at UNLV.3

He explains that the research shows that the central feature of diabetes, high blood sugar (hyperglycemia), impairs neural activity in ways that are similar to what is found in models of Alzheimer’s disease. This is the first evidence, he says, that shows neural activity changes due to hyperglycemia overlap with what is observed in Alzheimer’s disease.

Interestingly, the researchers found that two parts of the brain – the hippocampus and the anterior cingulate cortex – were over-connected. Why does that matter?

Well, when it came time to remember information and complete a task, these two regions – affected early in Alzheimer’s progression – were over-communicating, triggering errors.

Dr. Hyman offered this analogy to better paint the picture…

He compares this problem to a CEO who hands over the company’s operations to a son, who then elects to overturn previous communication structures and become the sole gatekeeper of information.

“The only communication the CEO has is with one person, as opposed to talking with all of the other people in the office,” Dr. Hyman says. “It is possible that in Alzheimer’s patients there’s over-connection in certain areas where there should be flexibility.” As a result, cognitive function suffers.

He adds that in the study models, researchers saw evidence of that in real-time, at crucial moments when subjects were asked to complete a task. These latest findings were published in the journal Communications Biology.4

Dr. Hyman and his team of researchers plan to further test specific mechanisms of the connection between high blood sugar and Alzheimer’s disease as well as potential treatments.

Age of Diabetes Onset Matters

Meanwhile, another research team has discovered that the younger you are when type-2 diabetes strikes, the higher your risk for Alzheimer’s disease and other forms of dementia years later.

This research is particularly concerning when you consider the rising rates of diabetes in younger folks, which are largely tied to obesity.

For this research the scientists used a large, ongoing medical cohort of 10,308 people aged 35 to 55 years. From 1985 to 2019, 1,710 cases of diabetes and 639 cases of dementia were recorded.

For every 1,000 people the rate of dementia was 8.9 in those without diabetes at age 70. When the researchers looked at those with diabetes they found more than double the rate of Alzheimer’s.

For example, for diabetics with diabetes onset up to five years earlier the rate of dementia was ten, for diabetes onset six to ten years earlier the rate of dementia was 13, and for diabetes onset more than ten years earlier the rate of dementia was 18.3.

These stunning results reveal that the earlier you develop diabetes, the greater your risk for dementia. The research was published in JAMA (Journal of the American Medical Association).5

How Does Diabetes Affect Brain Health?

Researchers are careful to say that while diabetes may not directly cause Alzheimer’s disease, it may contribute to its development.

Diabetes can affect brain health by raising the risk of heart disease, which in turn can damage blood vessels and block blood flow to the brain. Put simply, chronically high blood sugar is a recipe for poor brain health.

In addition, diabetes leads to an excess of insulin, which may alter the amount or status of other neurochemicals reaching the brain. This imbalance may lead to Alzheimer’s disease.

And finally, elevated blood sugar leads to inflammation. This may also damage brain cells and open the door to Alzheimer’s disease.

Of course, prevention is the best option, and the earlier the better.

Reducing Your Risk of Diabetes and Alzheimer’s Disease

Consult with a trusted health care professional to determine your blood sugar levels and address your lifestyle accordingly. Over the years a number of strong scientific studies have shown that lifestyle modifications such as weight loss, dietary changes, and exercise are critical for preventing and even managing type-2 diabetes. In some cases, these lifestyle changes can outperform blood-sugar lowering medications!

I recommend following a healthy diet rich in whole foods, avoiding processed foods and refined sugars as much as possible. It’s also important to get ample exercise, manage daily stress, and bolster your psychological well-being by staying socially engaged with family, friends and your community.

And, I might add, these tweaks are essential for anyone who is concerned about developing Alzheimer’s disease– which is everybody!


  1. https://www.niddk.nih.gov/health-information/professionals/diabetes-discoveries-practice/addressing-
    stroke-risk-factors-in-people-who-have-diabetes
  2. Arvanitakis Z, Wilson RS, Bienias JL, Evans DA, Bennett DA. Diabetes mellitus and risk of Alzheimer disease and decline in cognitive function. Arch Neurol. 2004;61(5):661-6.
  3. https://www.sciencedaily.com/releases/2021/09/210928121324.htm
  4. Communications Biology, 2021; 4 (1) DOI: 10.1038/s42003-021-02558-4
  5. https://jamanetwork.com/journals/jama/fullarticle/2779197
  6. Ann N Y Acad Sci. 2015;1353:60-71. doi:10.1111/nyas.12807

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