Many sources encourage consumption of whole grains as part of a healthy, balanced diet, particularly emphasizing whole grains over refined grains as a way to reduce blood sugar spikes and insulin resistance, which can contribute to neurodegenerative disease. (Example: the otherwise fairly solid recommendations at https://www.parkinson.org/Living-with-Parkinsons/Managing-Parkinsons/Diet-and-Nutrition.) But we also need to reckon with inflammation. Most grains, especially including wheat, produce an inflammatory response in the gut1, which contributes to brain inflammation2. This response is far stronger with whole grains than with refined grains. The same stuff that we find unpalatable about brown rice or whole wheat bread is actually harder on our digestive system, full of lectins and other inflammatory compounds.
The simplest approach with grains is to not eat them at all. But that’s a pretty hard dietary change; if you’re going to eat them, choose the refined grain option instead. White rice instead of brown rice; regular pasta or bread instead of whole wheat. The impact on your blood sugar can be moderated by adding in fats, proteins or fiber along with the grains – having plenty of grass-fed butter with your rice or bread, for instance, or taking a (non-grain-based) fiber supplement before your meal.