The main nutrient for the brain are glucose & Oxygen

The main nutrient for the brain are glucose & Oxygen. but,

Eating a lot of sugar or other carbohydrates can be hazardous to both brain structure and function.

Diabetes, which is characterized by chronically high levels of blood glucose, has been linked to an elevated risk of dementia and a smaller hippocampus, a brain region critical for memory.

Glucose might directly contribute to hippocampal atrophy!

A study published in Neurology indicate that even in the absence of diabetes or glucose intolerance, higher blood sugar may harm the brain and disrupt memory function.