When Two Life-Altering Diagnoses Intersect: Attempting to Understand the Connections Between Diabetes and Alzheimer’s Disease

Both diabetes and Alzheimer’s disease are listed as two of the top ten leading causes of death in the United States, falling at numbers six and seven respectively, and claiming the lives of tens of thousands yearly.[1] On the offset, these two diseases may seem very different; while Alzheimer’s is known for damaging nerve cells in the brain, diabetes renders the body incapable of carefully controlling blood sugar levels. However, in recent years, scientific findings have found that those with diabetes – type 2 in particular – have an increased likelihood of developing Alzheimer’s disease. This post will focus upon what connects these two conditions and how new research can help us better understand both diseases.


Doubling the risk

While many are aware that type 2 diabetes may lead to other conditions, especially heart disease, patients and families are not typically expecting the risk of dementia to be doubled by this diagnosis.[2] However, the connection makes sense when you consider that both harm blood vessels; vascular dementia is caused by damaged blood vessels in the brain and diabetes can cause blood vessels to be hardened throughout the body.[3] The high levels of glucose suffered by diabetics that can cause the heart conditions many are so familiar with also have the capacity to inhibit enzymes from functioning properly in the brain, sowing the seeds for Alzheimer’s development.[4]


The Brain, Insulin, & Sugar

While it is clear the two diseases are linked, what is less clear is exactly why. What research has shown is that there are definitely connections in how both diseases complicate brain function and sugar control.

Many people with diabetes suffer brain changes – including mild cognitive impairment – which typically occur on more serious levels with Alzheimer’s and other forms of dementia.[5] Additionally, a 2015 study found that doses of nasal insulin that bypassed the blood/brain barrier significantly improved memory and mild cognitive impairment in people with early Alzheimer’s disease, demonstrating that like those with diabetes, Alzheimer’s patients struggle to produce enough insulin for proper bodily function.[6] Researchers think that this connection might be a sign that each condition can fuel the damage caused by the other.[7]

This leads to the important note that diabetes doesn’t necessarily cause Alzheimer’s disease. One Alzheimer’s researcher, Suzanne M. de la Monte, has argued that because an individual who doesn’t necessarily have diabetes might still develop insulin resistance in the brain, many cases of Alzheimer’s could be called Type 3 diabetes.[8] What with growing evidence supporting the concept that Alzheimer’s disease is fundamentally metabolic, with biochemical features that correspond with insulin resistance disorders, it’s important to look at what it has in common with diabetes to better treat it.[9]


Work that needs to be done

Research into understanding how diabetes affects brain cells is one way scientists are attempting to understand its connections with Alzheimer’s more fully. Additionally, clinical trials can be conducted to see whether a diabetes drug can be used as a dementia treatment.[10] Monitoring any blood changes in individuals at the early stages of Alzheimer’s disease may also be fruitful in determining the links.[11] Finally, looking into what further damages sugar can do to the brain will be vital in both developing a chronology of how Alzheimer’s progresses and learning how best to treat this disease as well as diabetes more effectively.[12]


Clearly, more research needs to be conducted in order to better diagnose, treat, and prevent both Alzheimer’s disease and diabetes. However, if current research is any indication, a promising future awaits those diagnosed with either of these diseases.

[1] Brophy Marcus, Mary, “The top 10 leading causes of death in the U.S.,” CBSnews.com, June 30, 2016,  http://www.cbsnews.com/news/the-leading-causes-of-death-in-the-us/

[2] Lerche, Olivia, “Diabetes could cause Alzheimer’s: Link between high blood sugar and dementia confirmed,” Express.UK, Feb. 23, 2017, http://www.express.co.uk/life-style/health/771077/diabetes-dementia-alzheimer-s-disease-high-blood-sugar

[3] Klein, Karin, “The Alarming Diabetes-Alzheimer’s Connection,” ASweetLife.org, May 24, 2017, https://asweetlife.org/the-alarming-diabetes-alzheimers-connection/

[4] Lerche, “Diabetes could cause Alzheimer’s”

[5] “Diabetes and Alzheimer’s linked,” MayoClinic.org, n.d., http://www.mayoclinic.org/diseases-conditions/alzheimers-disease/in-depth/diabetes-and-alzheimers/art-20046987

[6] Klein, “The Alarming Diabetes-Alzheimer’s Connection”

[7] “Diabetes and Alzheimer’s linked”

[8] Klein, “The Alarming Diabetes-Alzheimer’s Connection”

[9] Ibid

[10] Ibid

[11] Lerche, “Diabetes could cause Alzheimer’s”

[12] Ibid