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Do Carbs Kill Cognition?

How Carbs Impact Your Brain

Nature vs. nurture. The topic's been discussed back and forth for decades, and we learn more about the impact our choices have on our cognitive function every day. Most recently, research has focused on our diet, and whether or not it can affect our focus and learning ability. Hint: it can.

First, let’s set the table. We all consume calories (some more than others), and those calories are made up of three macronutrients: carbohydrates, protein, and fats. Simple enough, right? Of these ‘macros’, carbs have become a staple for more than 80% of people around the world.

So, what’s a carb? Put simply, it’s a food that contains sugar, starch, and cellulose. Walk into any grocery store, throw a stone, and you’re likely to hit a food item that contains carbs — think things like maize, rice, and wheat.

But, isn’t that a good thing? People around the world have abundant access to cheap, plentiful foods that provide energy. Well, in theory, yes, but it becomes a problem when we overdo it. Modern-day diets are evolving. Instead of eating in moderation to provide our daily energy needs, we binge on quick-fix foods like pizza, burgers, and ice cream.

That’s the issue when it comes to cognition.

In one study, researchers took nearly 250 schoolchildren aged 6-7 years old1, with an average daily refined carb consumption of around 285 grams. Of those children, the 30% who consumed the most carbs daily did worse when tested on non-verbal general intelligence (Tests designed to evaluate ability to reason by analogy, spatial organization, and to make comparisons).

In another study, something similar happened. This time, adults aged around 90 were studied2.

In those with a diet made up of more than 58% carbs and 27% sugar, there was a higher risk of developing mild cognitive impairment or dementia. Conversely, those who ate more fat (32-35%) and protein (19-20%) were less likely to have diminished mental faculties.

Let’s draw an analogy. You know diabetes and how excess sugar (glucose) in the blood causes it. Well, given that glucose is the primary source of energy for the brain, eating way too much of it could be likened to having ‘diabetes in the brain’2.

Now, we don’t have a clear understanding of how carbs affect our ability to think, but researchers have suggested that a process called ‘glycosylation’ may be responsible3.

That’s when excess glucose sticks to molecules it shouldn’t be stuck to, like proteins and fats. This is thought to lead to oxidative stress, and consequently, cognitive decline3.

Alarming, right? Here’s an important caveat — these are results from a few studies, and other research doesn’t 100% agree with the conclusions presented above. As with any emerging field, we need more studies to present a clearer and more uniform picture of how carbs affect our cognitive abilities.

Until then, we’d recommend remembering that old adage—you are what you eat. It’s so easy to reach for a quick, 1000 calorie fix of pizza, but it’s a little more difficult to plan a day of healthy, clean eating. Which do you think is a better investment in your future?

Speaking of that future, we’re in the business of helping you stay on top of yours.

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  1. Abargouei AS, Kalantari N, Omidvar N, Rashidkhani B, Rad AH, Ebrahimi AA, Khosravi-Boroujeni H, Esmaillzadeh A. Refined carbohydrate intake in relation to non-verbal intelligence among Tehrani schoolchildren. Public Health Nutr. 2012 Oct;15(10):1925-31. doi: 10.1017/S1368980011003302. Epub 2011 Dec 9.

  2. Roberts RO, Roberts LA, Geda YE, et al. Relative Intake of Macronutrients Impacts Risk of Mild Cognitive Impairment or dementia. Journal of Alzheimer’s disease : JAD. 2012;32(2):329-339. doi:10.3233/JAD-2012-120862.

  3. Yaffe K, Lindquist K, Schwartz AV, Vitartas C, Vittinghoff E, Satterfield S, Simonsick EM, Launer L, Rosano C, Cauley JA, Harris T. Advanced glycation end product level, diabetes, and accelerated cognitive aging. Neurology. 2011;77:1351–1356.