I know this is not a comparative physiology topic, but this article caught my attention as I know I just ate a rather high fat meal last week for Thanksgiving and I plan to do the same throughout the holiday season.
Insulin does more than just lowering blood sugar by increasing its uptake into tissues. It can also increase blood flow to the hippocampal region of the brain to help cognitive function. This area of the brain is important in memory formation and spatial orientation. A new study published in the American Journal of Physiology – Endocrinology and Metabolism used ultrasound to measure blood flow to this region of the brain in rats fed either a normal fat or high fat diet for 6 months. Their results show that eating a high fat diet over a long period of time causes blood vessels in the brain to lose their ability to respond to insulin, meaning blood flow to the region is reduced. Because this area is so important in our ability to recall information, the researchers speculate that insulin resistance in the brain of people who are obese or diabetic may help explain why they experience cognitive impairments or even dementia.
Z Fu, J Wu, T Nesil, MD Li, KW Aylor, Z Liu. Long-term high-fat diet induces hippocampal microvascular insulin resistance and cognitive dysfunction. Articles in PresS. American Journal of Physiology – Endocrinology and Metabolism (November 29, 2016). doi:10.1152/ajpendo.00297.2016