Sweeteners & Smarts

I was recently at Starbucks during a layover in Charlotte and noticed the variety of sweeteners for everyone's super-sweet frappachino or if you're like me, a black coffee. Some are packaged as "healthy", and some aren't even trying to pull off the facade because we've been taught anything with zero calories is okay.

Along the sweetener topic, a recent study just came out showing a decrease in mental/cognitive performance after using sweeteners.

Participants consumed sweetened drinks with glucose, also called dextrose, sucrose, table sugar, fructose, sugar from fruit, or sucralose, an artificial sweetener, before three cognitive tests. The tests measured response time, a math problem, and a stroop task all while logging blood glucose levels.

Those who had consumed glucose or sucrose performed worse on the cognitive tests than those who had consumed fructose or sucralose. We convert sucrose into glucose and fructose. Fructose does not cross the blood-brain barrier like glucose. The researchers go on to suggest that 'sugar coma' is a real phenomenon as attention declines after ingestion of glucose.

Highlights from the "sweet effect" study [1]:

  • Glucose and sucrose ingestion led to negative cognitive performances.
  • Negative effects due to blood glucose increase were more evident with overnight fasting.
  • Sugar effects on cognitive abilities are likely to be glucose-mediated.
  • Sweetness perception does not play a role in moderating cognitive performances.

Back to the Starbucks sweeteners pictured. This is a typical selection at any chain or local coffee shop.

  • Very bad - Avoid at all costs
    • Super refined and/or fake
  • Semi bad - Use if only in a pinch (get it?)
    • A bit more natural ... use only a pinch in a pinch
  • Okay (not pictured) - Okay for moderate use
    • Stevia (make sure its pure)
    • Monk fruit
    • Zero to very little glucose/insulin impact (per current research)
  • Always good
    • No sweetener
    • Water :)

Use this guidance when choosing to satisfy your tongue. Remember your best option is to avoid any sweetener of any kind by sticking with black coffee or water not only to retain cognitive abilities, but to avoid any negative changes in fat and energy metabolism. It was also found that replacing sugar with artificial substitutes can lead to diabetes and obesity [2].

As for me, I typically avoid sugar and sweeteners at all costs even before reading this latest cognitive study. I stick to black coffee or my daily home brewed espresso with oat milk by Oatly. If I'm in need of sweetener for pre-workout BCAA mix, I leverage a pure stevia extract or stevia liquid drops with zero measurable impact on glucose/insulin levels.