What Does Excess Fructose Do To our Body?

It's a fact that excess dietary fructose can harm your body by setting up the conditions for diabetes, obesity, and fatty liver, but what does it do to your brain? Studies have not addressed this question—until now.

A new UCLA study1 is the first to show how a steady diet high in fructose can damage your memory and learning. The study was published in the Journal of Physiology.

Researchers investigated the effects of high-fructose syrup, similar to high fructose corn syrup (HFCS), a cheap sweetener six times sweeter than cane sugar, which is used in most  soft drinks, processed foods, condiments, and even many baby foods.

The team sought to study the effects of a steady intake of this super-processed, concentrated form of fructose, which is quite dissimilar from the naturally occurring fructose in fruits. They fed rats a fructose solution as drinking water for six weeks, then tested their ability to remember their way out of a maze.The results certainly grabbed the researchers' attention.

The rats fed fructose syrup showed significant impairment in their cognitive abilities—they struggled to remember their way out of the maze. They were slower, and their brains showed a decline in synaptic activity. Their brain cells had trouble signaling each other, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier.

Additionally, the fructose-fed rats showed signs of resistance to insulin, a hormone that controls your blood sugar and synaptic function in your brain.

Because insulin is able to pass through your blood-brain barrier, it can trigger neurological processes that are important for learning and memory. Consuming large amounts of fructose may block insulin's ability to regulate how your brain cells store and use sugar for the energy needed to fuel thoughts and emotions. The average American consumes roughly 47 pounds of cane sugar and 35 pounds of high-fructose corn syrup per year, according to the U.S. Department of Agriculture2.