In the second instalment of this two-part series, we’ll continue our investigation of brain foods by exploring the effect of fat (specifically omega-3 fatty acids), carbohydrates, and one’s overall diet.

 

Omega-3s

Omegas-3s are synonymous with brain health. As a matter of fact, anthropologists have found that early humans who lived near coastal areas and consumed diets high in fish (which are rich in omega 3s), evolved to have larger brains sooner than populations living in landlocked areas. Omega-3s are essential: you’re reading this right now and thinking with the help of omega-3s. Despite their importance, omega 3s are only found in a limited number of foods (such as fish, algae, flaxseed and walnuts); furthermore, they disappear from the food supply because of their reactivity, which limits the shelf life of products containing them.

Because of scarcity, many people turn to omega-3 supplements. Can omega-3 supplements actually improve university students’ cognition? A recent study published in the journal Human Pharmacology: Clinical and Experimental showed that omega-3 supplementation (particularly supplements rich in EPA, a specific type of omega-3) can improve neural efficiency in young people. Furthermore, a recent review reached the same conclusion.

However, Dr. Chuck Chen, a recent graduate of the Department of Nutritional Sciences who specializes in omega-3 fatty acids and brain health commented, “Even though studies have found higher cerebral blood flow and brain activation following omega-3 supplementation, this largely does not translate to improvements in cognition… in young, healthy adults.” He warned about the methodological details which can often bias results stating, “the dietary intakes of omega-3s in [the study] were not measured so it is hard to know if the supplementation is replenishing deficient stores or adding to the adequate stores of these young adults.” Therefore, while it’s a good idea to consume omega-3-rich foods to prevent deficiency (which can lead to depression), the benefit of supplementation is controversial.

 

Carbohydrates

While the brain is largely made from fat, it runs on carbs. The brain can’t store carbs, it relies on a steady supply delivered from the blood stream. As a matter of fact, intensive cognitive demand can cause a reduction in peripheral blood glucose, thus illustrating the brain’s demand for glucose. Considering this, it’s understandable that low glycemic index carbohydrates (such as oats, barley, bulgur, brown rice, whole grain bread, whole grain pasta, and bran cereals) have been shown to significantly improve cognitive function relative to high-glycemic index carbs.

This is because low-glycemic index carbs spend more time in your stomach, and are absorbed more slowly, providing a steady supply of glucose into the blood stream and thus the brain. High glycemic  index carbs (such as white rice, white bread, candy and baked goods) are rapidly digested and absorbed. They provide a rush of energy and spike your blood glucose, which might give you an immediate lift, but probably won’t carry you through to the end of the exam.

 

The whole diet…

At the end of the day, optimal cognitive performance is about more than just consuming one single food. While there are no studies investigating the effect of dietary patterns on cognitive performance, there’s some pretty compelling evidence illustrating the link between overall diet quality and brain health. For example, the Mediterranean diet (rich in olive oil, nuts, beans/legumes, and fish, while low in meat and dairy) has been shown to decrease risk for depression while consumption of fast-food and commercial baked goods is associated with increased risk for depression. It’s logical that at the end of the day, a balanced healthy diet is the surest way to optimal brain health.

Mary Scourboutakos is a PhD student in the Department of Nutritional Sciences. Read the first half of this series here.