When enjoyed in moderation, whole grains can be a fantastic part of a healthy diet as a nutrient-dense source of carbohydrates, dietary fiber, and folic acid.
Let's back up a moment: just what are "whole grains," exactly?
Whole grains, as the name suggests, are grain kernels that are whole; that is, they have every part of the natural kernel, which are the endosperm, the germ, and the bran. They are more nutritionally complete than refined grains, which only contain the endosperm. Examples of whole grains include brown rice, barley, and quinoa.
Here's why whole grain could be a great part of a brain-healthy diet: some research indicates that a diet lacking in whole grains could contribute to greater risk of inflammation and cognitive impairment. Furthermore, a deficiency of folic acid, found abundantly in whole grains like quinoa, can lead to poorer mental health outcomes and increased risk of dementia in elderly individuals. It's therefore no surprise that international dietary guidelines recommend whole grains as part of a well-rounded diet.
NOTE: Just be careful when shopping around; not all items labeled "whole grain" are healthy as they can contain lots of added sugar or other less-than-healthy added ingredients.