In Fall of 2013, I learned that I had pre-diabetes. This was a huge wake-up call for me. As someone with a family history of diabetes, of course I was concerned about developing diabetes. However, as someone with a family legacy of Alzheimer’s, I had a greater concern. When I heard “pre-diabetes”, I also heard “pre-Alzheimer’s” and this really scared me.
While diabetes has long been implicated as a significant risk factor for Alzheimer’s disease or dementia, a 2013 study showed that people with high blood sugar levels are at increased risk of dementia, even when they don’t have diabetes. Furthermore, I was aware of research showing that people with pre-diabetes show early signs of the brain changes that are associated with Alzheimer’s (this 2011 study, for example). So my pre-diabetic brain was essentially a “pre-Alzheimer’s brain”.
You may have heard that Alzheimer’s disease is being called “Type 3 Diabetes”. This is a term coined over 10 years ago by Dr. Suzanne de la Monte, a neuropathologist at Brown University (2005 study). Dr. de la Monte, along with many other researchers, views Alzheimer’s disease as a metabolic disease stemming from chronic deficits in insulin signaling in the brain (2014 review). Since glucose is the primary fuel for the brain, impaired insulin signaling leads to insufficient glucose uptake and utilization, which leads to “brain starvation” and cognitive impairment.
Diabetes and pre-diabetes are usually accompanied by insulin resistance, which means it takes much higher levels of insulin to do the job of reducing high blood sugar. Excess insulin is degraded by Insulin-Degrading Enzyme (IDE) which serves the additional function of assisting with the clearance of beta-amyloid from the brain. So if IDE is pre-occupied with the function of degrading insulin, it is not available to clear beta-amyloid, leading to the accumulation of beta-amyloid, which is the hallmark sign of Alzheimer’s disease.
So, as someone at significant risk of developing Type 3 Diabetes/ Alzheimer’s disease, blood sugar control and reducing insulin resistance is really important. I personally strive to keep my blood sugar levels below 120 at all times. To do this, I used (and continue to use) a blood glucose meter to learn what foods caused high blood sugar levels in MY body. Foods with added sugars, refined carbs were obvious, but some things were a surprise- like brown and black rice, which might be due to my Chinese genetic background (2013 study).
I also learned how to reduce blood sugar spikes by adding more protein and healthy fat into my food plan. Incorporating healthy fat was probably the most challenging because I had bought into the low-fat dietary recommendations from the last 30 years. But, “good” fats (such as nuts, seeds, avocado, wild-caught fish, olive oil, coconut oil, etc.) are essential for healthy brain function, especially when your brain is starving due to insulin resistance.