One of the most striking studies on carbohydrates and brain health revealed that high-carb diets increase your risk of dementia by a whopping 89 percent, while high-fat diets lower it by 44 percent. According to the authors, “A dietary pattern with relatively high caloric intake from carbohydrates and low caloric intake from fat and proteins may increase the risk of mild cognitive impairment or dementia in elderly persons.”
Studies also strongly suggest Alzheimer’s disease is intricately connected to insulin resistance;8 even mild elevation of blood sugar is associated with an elevated risk for dementia.9 Diabetes and heart disease are also known to elevate your risk, and both are rooted in insulin resistance.
This connection between high-sugar diets and Alzheimer’s was again highlighted in a longitudinal study published in the journal Diabetologia in January 2018.11 Nearly 5,190 individuals were followed over a decade, and the results showed that the higher an individual’s blood sugar, the faster their rate of cognitive decline.
Research16 published in 2013 also showed that sugar and other carbohydrates can disrupt your brain function even if you’re not diabetic or have any signs of dementia. Here, short- and long-term glucose markers were evaluated in healthy, nondiabetic, nondemented seniors. Memory tests and brain imaging were also used to assess brain function and the actual structure of their hippocampus.
The findings revealed that the higher the two blood glucose measures, the smaller the hippocampus, the more compromised its structure, and the worse the individual’s memory was. According to the authors, the structural changes in the hippocampus alone can partially account for the statistical link we see between glucose and memory, as your hippocampus is involved with the formation, organization and storage of memories.
The results suggest glucose directly contributes to atrophy of the hippocampus, which means that even if you’re not insulin resistant or diabetic, excess sugar can still hamper your memory. The authors suggest that “strategies aimed at lowering glucose levels even in the normal range may beneficially influence cognition in the older population.”