The simple answer to the above questions is YES! There is a closer correlation than what you might think. Research over the past 10 years indicates the increase in Diabetes related Alzheimer’s by 50-150%, with researchers also leading us to the concept that impaired insulin signaling has an important role in the pathogenesis of Alzheimer’s and the proposal that Alzheimer’s represents “Type 3 Diabetes”. As there is an increase in the aging population worldwide, evidence suggests that there will be 115 million people worldwide who will suffer from Alzheimer’s by the year 2050.
Where is the connection?
Firstly, let’s talk about Diabetes. Diabetes can either be autoimmune (Type 1) or caused by insulin resistance in peripheral tissues and is most frequently associated with aging, a family history of diabetes, obesity, and failure to exercise (Type 2). Insulin receptors are expressed on all cell types in the body, including the brain. Insulin resistance has long been recognized as a central feature of Type 2 Diabetes, but research from the past few years has shown that it also occurs in the brains of individuals.
Insulin enters the Central Nervous System (CNS) across the capillary endothelial cells of the blood–brain barrier. Insulin has intense effects in the CNS, regulating key processes such as energy homeostasis, neuronal survival, learning, and memory. Within the brain, insulin receptor density is highest in the olfactory bulb, hypothalamus, hippocampus, cerebral cortex, and cerebellum which suggests that insulin signaling has an important and diverse role in the brain.
Evidence suggests that systemic insulin resistance or high circulating levels of insulin affects the function of the blood-brain barrier resulting in a change of permeability which could lead to impairments in glucose utilisation and energy metabolism, resulting in neurodegeneration. This can cause Mild Cognitive Impairment (MCI) leading to early stages of dementia, in particular, Alzheimer’s. Alzheimer disease is the most common form of dementia among the elderly and is characterized by progressive loss of memory and cognition.
Will I develop Alzheimer’s if I have Diabetes?
The simple answer is NO! Not if the individual manages their diabetes correctly through intervention strategies such as diet and exercise. Exercise can reduce the risk of further chronic disease progression through changes in; fat mass, blood pressure, insulin sensitivity, glycaemic control, neural adaptations and many other cellular adaptations.
A study conducted by Northey and colleagues in 2018 concluded that a combination of aerobic and resistance exercise significantly increases cognitive function through vascular adaptations and promotion of neurogenesis, leading to reduced cellular damage.
Overall, exercise intervention is a promising, cost-effective treatment that can aid in Diabetes management and benefits cognitive function reducing the risk of dementia. On the other hand, for patients with Alzheimer’s disease, exercise intervention could slow down the rapid cognitive impairment.
As Accredited Exercise Physiologists we can help provide these services leading to a healthier lifestyle and providing exercise as medicine. If you would like more information you can email on firstname.lastname@example.org to book a consultation with one of our team members.
Joel Skinner (B.Sc Exercise Science and Rehabilitation)
Accredited Exercise Physiologist (AEP) (AES) (ESSAM)
Arnold, S. E., Arvanitakis, Z., Macauley-Rambach, S. L., Koenig, A. M., Wang, H. Y., Ahima, R. S., Craft, S., Gandy, S., Buettner, C., Stoeckel, L. E., Holtzman, D. M., & Nathan, D. M. (2018). Brain insulin resistance in type 2 diabetes and Alzheimer disease: concepts and conundrums. Nature reviews. Neurology, 14(3), 168–181. doi:10.1038/nrneurol.2017.185
Northey, J.M., Cherbuin, N., Pumpa, K.L., Smee, D.J., Rattray, B. (2018) Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. British Journal of Sports Medicine. 52 (3), 154-160. doi:10.1136/bjsports-2016-096587
Butterfield, D. A., Di Domenico, F., & Barone, E. (2014). Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochimica et biophysica acta, 1842(9), 1693–1706. doi:10.1016/j.bbadis.2014.06.010