Glucose Vs. Fructose (And Why Fructose Is So Bad For You)

What’s the difference between glucose and fructose?

A lot, according to your brain!

Glucose is a simple sugar derived from the breakdown of carbohydrates, and it is what fuels the brain. Fructose on the other hand is a relatively new dietary staple for the brain. And it’s not a good one. Until the 1970’s, most fructose entering the human body was in the healthy form of fruit; healthy because the fructose was in small quantities and offset by healthy dietary fiber and antioxidants. With the advent of the high fructose corn syrup revolution though, the amount of fructose that entered the human body on a daily basis skyrocketed. High fructose corn syrup (HFCS) and other plant-based fructose derivatives are a cheap alternative to real sugar that also lengthens shelf-life. Although there are a number of studies and websites claiming the relative harmlessness of HFCS, more and more studies are pointing to all of the negative effects it has on the human body.

Studies have shown that the adverse effects of fructose are particularly bad for the brain. Fructose, unlike glucose, is metabolized directly by the liver. The excessive sugar content significantly increases the amount of fatty triglycerides the body produces, causing fatty liver disease, increasing the risks of heart disease, and, once circulated up to the brain, causing cognitive deficits.

In one study conducted by UCLA, male animals given fructose-laced water became unable to remember landmarks in a maze, and their brain cells were shown to have trouble transmitting signals between neurons. Oddly enough, female animals did not display the same cognitive deficits after their triglyceride levels sky-rocketed, implying that estrogen may help to mitigate some of the negative effects of fructose.

That’s no reason for women to consider themselves immune to the effects of fructose however! Although the effects on memory might not be as significant in females, high levels of triglycerides in the body may fuel insulin resistance in the brain cells. High levels of insulin in the brain disturb brain function by inhibiting the ability of brain cells to take up glucose. Insulin resistant brain cells are less able to take up their favorite food, glucose. Without their usual fuel, the functioning of neurons and the brain cell’s ability to produce and respond to neurotransmitters can be impaired.

Additionally, with recent research about the way in which HFCS significantly raises the risk of heart disease, both women and men should be vigilant about the products they consume. A recent study done on the effects of HFCS on the body showed that even in small quantities, the levels of lipoproteins, triglycerides, and uric acid (all heart disease risk factors) shot up significantly after the consumption of drinks containing HFCS over a two week period.

So, what should you do to reduce your risk of cognitive degeneration and heart disease? Most of the processed foods on the market today contain HFCS, but so do a surprising number of foods that most of us would consider to be healthy! Your Dannon yogurt for instance? What about that Power Bar? The most effective way to avoid HFCS is to read labels. Carefully.