Brain health is intimately linked to heart health and glucose homeostasis (regulation of blood sugar).
The brain is extremely vulnerable to the deleterious effects of chronic hypertension. The most extreme manifestation of this link is hypertensive encephalopathy.
High blood pressure causes the cerebral circulation (blood flow in the brain) to adapt in ways that predispose to stroke and occlusion (blockage) of the vasculature (blood vessels) in the brain. Chronic, low-grade hypertension results in poorly-perfused neural tissue, ischemia, and impaired clearance of toxic metabolites.
Accelerated brain aging is well-documented amongst hypertensive patients. Elevated blood pressure increases the probability of microinfarctions (microscopic strokes), which are likely the second most significant cause of dementia.
Diabetes harms the brain through a different mechanism. Some researchers have termed Alzheimer’s disease “Diabetes type 3”[^1], suggesting that the pathophysiology of dementia involves features of diabetes like chronically elevated blood sugar (hyperglycemia) and insulin resistance.
It is no surprise that the regulation of blood sugar is so important to brain health. Glucose is the main substrate for cerebral metabolism. Since sugar uptake in cells is mostly an insulin-dependent process (depending on the cell type), insulin resistance or impaired insulin secretion essentially starves cells of fuel! Ironically, while cells are starving, there is a surplus of sugar in the circulatory system. This elevated blood glucose sugar-coats and damages proteins.
Now that we fully appreciate how brain health is linked to blood sugar, diabetes, hypertension and cardiovascular health, we can delve into preventive dietary choices.
Brain Protip. Here’s a list of foods that contain trans-fat or partially hydrogenated vegetable oils: coffee creamer, crackers, cookies, cakes, frozen pies, and other baked goods, fast food, frozen pizza, ready-to-use frostings, refrigerated dough products (e.g., biscuits and cinnamon rolls), snack foods (microwave popcorn), vegetable shortenings and stick margarines.
And a list of foods associated with trans fat:
These suggestions will be familiar and obvious to many readers.
But when it comes to nutrition, it is important to return to basic principles of health. Eating for brain health starts with dietary choices that lower blood sugar and blood pressure, reduce the risk of developing diabetes, and unclog the circulatory system.
Next, we’ll consider particular foods that confer benefits to the brain.
[^1]: De la monte SM, Wands JR. Alzheimer's disease is type 3 diabetes-evidence reviewed. J Diabetes Sci Technol. 2008;2(6):1101-13.