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Most people know there are type 1 and type 2 diabetes, but few people know there is now an illness being labeled as type 3 diabetes. The label “type 3 diabetes” has only recently come into use. While official health organizations may not yet use this label, type 3 diabetes is now a term that is being used to refer to Alzheimer’s disease. But why is Alzheimer’s disease being called diabetes type 3? What does this mean for the treatment of Alzheimer’s disease? And what research still needs to be done?
What Is Diabetes Type 3?
First, it’s important to note that type 3 diabetes is not the same as type 3c diabetes. Type 3c diabetes mellitus, also known as T3cDM or pancreatogenic diabetes, is an illness that develops due to conditions that affect the pancreas. While these labels sound similar, they are radically different.
Type 3 diabetes is being used to refer to Alzheimer’s disease. The term “type 3 diabetes” is being used to describe the fact that Alzheimer’s has a strong link to insulin resistance.
According to Live Science, “Insulin resistance may be a leading cause of dementia, as this glucose metabolism deficiency in the brain contributes to symptoms such as loss of memory, decrease in judgment and reasoning skills.”
Why Is Alzheimer's Being Called Diabetes Type 3?
Insulin resistance has been identified as being involved in conditions like obesity, dementia, and diabetes. Specifically, insulin resistance and decreased insulin signaling in the brain may play a role in the development of Alzheimer's disease, and insulin resistance is one of the main problems in type 2 diabetes (the other is that the pancreas can't make enough insulin to keep blood sugar levels within a healthy range; see here) This insulin-resistance connection is one of the ways that it’s clear that diabetes and Alzheimer’s disease are linked. We also know that those with type 2 diabetes have a significantly higher risk of developing Alzheimer's disease.
This is why, in 2008, Dr. Suzanne de la Monte and Dr. Jack Wands of Brown University suggested that Alzheimer's disease be termed type 3 diabetes in their review in the Journal of Diabetes Science and Technology.
Causes of Type 3 Diabetes
The cause of type 3 diabetes, Alzheimer's disease, is not fully understood. What is known is that age-related changes in the brain, along with environmental, genetic, and lifestyle factors, all play a role in who gets Alzheimer's disease. It’s important to note that while aging is a major factor in developing Alzheimer's disease, Alzheimer's disease is not a normal part of aging.
According to Live Science, alongside aging, the following factors put a person at additional risk of Alzheimer's disease:
• A family history of Alzheimer's disease
• A history of moderate traumatic brain injury
• Having type 2 diabetes (this actually doubles one’s risk)
• Lack of exercise
• Poor diet
• Lack of sleep
● Recent studies are also showing gut inflammation which gets transmitted to the brain leading to secondary brain inflammation. This gut inflammation is also a likely contributing factor to the development of the insulin resistance as well. Gut inflammation associated with age and Alzheimer's disease pathology: a human cohort study.
What Are the Symptoms of Type 3 Diabetes?
Type 3 diabetes or Alzheimer's disease includes symptoms that may be similar to that which is seen in normal aging, but to a greater extent. For example, getting confused about the day of the week but remembering it later may be normal for some older people, but forgetting the seasons and not understanding the passage of time is not.
According to the Mayo Clinic, the brain changes associated with Alzheimer's disease include six categories:
1. Memory – Memory loss becomes severe over time and affects one’s ability to function. For example, a person with Alzheimer's disease may repeat statements and questions many times or get lost in familiar places. It is important to recognize that memory loss is NOT a normal result of aging and that dementia should always be investigated in elderly individuals.
2. Thinking and reasoning – Thinking about abstract concepts like numbers becomes more difficult, as does multi-tasking. For example, a person with Alzheimer's disease may not be able to manage their own finances or possibly even recognize numbers.
3. Making judgments and decisions – Sensible decisions about everyday situations can become very difficult. For example, a person with Alzheimer's disease may not dress appropriately or not know how to handle situations like when something is burning on the stove.
4. Planning and familiar tasks – Routine tasks that require steps completed in a specific order can become difficult. For example, a person with Alzheimer's disease may not be able to follow a recipe or play a card game with familiar rules.
5. Changes in personality and behavior – Moods and behaviors can change with Alzheimer's disease. Examples of this include a loss of interest in activities, depression, distrust in others, loss of inhibitions and increased agitation.
6. Preserved skills – While some skills, such as those mentioned above, may diminish quickly, some types of skills stay preserved for longer. This may be due to the fact that they reside in parts of the brain that aren’t affected, at least initially, by the disease. These include skills like reading or listening to books, telling stories, sharing memories, singing, listening to music, dancing, drawing, or doing crafts.
If these symptoms are distressing or persist, it’s important to see a doctor. Memory loss and other dementia symptoms can be caused by a variety of conditions, so it’s important to know which condition a person might have for the most successful treatment.
If you see these symptoms in a loved one, it’s important to talk about them, as your loved one might not be aware of the extent of the changes. Suggest going to a doctor together for support and so that the doctor can get a complete picture of what your loved one is experiencing.
How Is Type 3 Diabetes Treated?
A study in the Journal of Neural Transmission Supplement linked diabetes with declining brain health, and a 2018 review in Frontiers in Neuroscience showed how targeting impaired insulin signaling with antidiabetic drugs could possibly be used to treat dementia and protect the brain.
While there is no known cure for type 3 diabetes (Alzheimer's disease), medications can be prescribed to maintain function and slow the progression of the disease. These medications are often cholinesterase inhibitors, which are medicines that work by boosting levels of cell-to-cell communication. It is this communication that can be lost in Alzheimer’s disease.
According to the Mayo Clinic, cholinesterase inhibitors may improve symptoms related to behavior, such as agitation or depression. Commonly prescribed cholinesterase inhibitors include:
• Donepezil (Aricept)
• Galantamine (Razadyne ER)
• Rivastigmine transdermal patch (Exelon)
Another medication that is prescribed for those with Alzheimer's disease is memantine (Namenda). Memantine is used to slow the progression of the symptoms in those with moderate to severe Alzheimer's disease. It may be used in combination with a cholinesterase inhibitor.
Additional medications like lecanemab (Leqembi; an intravenous infusion) and aducanumab (Aduhelm) may also be prescribed.
A Secure and Supportive Environment for the Person with Alzheimer's Disease, Type 3 Diabetes
A treatment plan for type 3 diabetes, Alzheimer's disease, also needs to include the creation of a safe and helpful environment that adapts to the person’s needs. A routine and habits that require less memory can be useful.
The Mayo Clinic suggests some of these ways to help a person with Alzheimer's live more successfully:
• Keep valuables, like keys or a wallet, in the same location all the time.
• Keep medicines in a secured location and use an app or daily checklist to keep track of doses.
• Arrange for automatic withdrawal of bills and automatic deposit of payments.
• Have the person always carry identification. Also, have them carry a phone with location tracking turned on. Program important numbers into the phone. Alternatively, have the person use a medical alert pendant or watch with location tracking.
• Create a schedule. For example, make meals at the same time every day and make appointments on the same day and time as much as possible.
• Use a whiteboard or calendar to track daily activities. Check off items throughout the day.
• Keep objects of meaning, like pictures, around the house.
For the complete link of ways to help a person with Alzheimer's disease, see here.
Future Areas of Research on Type 3 Diabetes
The areas of research around type 3 diabetes-termed Alzheimer’s disease are many. While the link between Alzheimer’s disease and diabetes being related to insulin resistance in the human body is now being recognized, scientists are still far from understanding it fully. Additional information about the impact of insulin resistance on the brain is still being sought. What’s more, it’s unclear if any medication that treats diabetes, such as dapagliflozin (Farxiga) or empagliflozin (Jardiance), would treat Alzheimer's disease as well. At this point, it’s understood that the brain still holds many mysteries, including those related to Alzheimer’s disease.
Sources
1. Alzheimer’s disease - Diagnosis and treatment - Mayo Clinic. (2023, August 30). https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/diagnosis-treatment/drc-20350453
2. De La Monte, S. M., & Wands, J. R. (2008). Alzheimer’s Disease is Type 3 Diabetes—Evidence Reviewed. Journal of Diabetes Science and Technology, 2(6), 1101–1113. https://doi.org/10.1177/193229680800200619
3. Ferreira, L. S. S., Fernandes, C. S., Vieira, M. N. N., & De Felice, F. G. (2018). Insulin resistance in Alzheimer’s disease. Frontiers in Neuroscience, 12. https://doi.org/10.3389/fnins.2018.00830
4. Hobbs, H. (2023, March 24). Type 3 diabetes and Alzheimer’s disease: what you need to know. Healthline. https://www.healthline.com/health/type-3-diabetes
5. Kellar, D., & Craft, S. (2020). Brain insulin resistance in Alzheimer’s disease and related disorders: mechanisms and therapeutic approaches. Lancet Neurology, 19(9), 758–766. https://doi.org/10.1016/s1474-4422(20)30231-3
6. Mudge, L., & Breslow, R. (2022). Type 3 diabetes: Symptoms, causes and treatments. livescience.com. https://www.livescience.com/type-3-diabetes
7. Richards, L. (2023, June 9). Type 3 diabetes explained. https://www.medicalnewstoday.com/articles/type-3-diabetes
8. Type 2 diabetes - Symptoms and causes - Mayo Clinic. (2023, March 14). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/syc-20351193
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