How Fructose Makes You Stupid and Fish Makes You Smart

This is yet another study in support of the low fructose, and adequate omega 3 recommendations in Bulletproof Diet.

Not only does excess fructose give you fatty liver disease, high triglycerides, fungal infections, diabetes, gout, and make you obese, it also hurts your brain function.

In this new study, two groups of rats were fed regular rat chow and drinking water for five days.  They also trained in a maze twice a day for five days before starting the experiment.  The researchers tested the rats’ ability to navigate the maze before giving them a very un-bulletproof intervention.  For the next six weeks, both groups of rats had their water replaced with a fructose solution.  However, the researchers decided to also give one group of rats DHA.  DHA is an essential fatty acid that’s needed to transmit signals between brain cells and to make new nerve tissue.  Their hope was that DHA would protect against any drop in mental performance caused by fructose.

“DHA is essential for synaptic function — brain cells’ ability to transmit signals to one another,” said Fernando Gomez-Pinilla, the lead author of the study. “This is the mechanism that makes learning and memory possible. Our bodies can’t produce enough DHA, so it must be supplemented through our diet.”

DHA vs. Fructose

After the six-week trial period, the rats were tested again on their ability to navigate the maze.  The rats that were given fructose without DHA had a significant reduction in brainpower.  It took them far longer to navigate the maze.  Moreover, they were also insulin resistant.  This was especially true for their brain cells, which were less sensitive to insulin than when they were drinking regular water.  This means they were more likely to become fat if the study continued.

“The second group of rats navigated the maze much faster than the rats that did not receive omega-3 fatty acids,” Gomez-Pinilla said. “The DHA-deprived animals 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.”

Interestingly, the rats’ insulin resistance and impaired brain function may have both been caused by fructose.  Insulin controls blood sugar, but it also influences brain function and memory.  Being insulin resistant may have decreased the rat’s brain function, “because insulin can penetrate the blood–brain barrier, the hormone may signal neurons to trigger reactions that disrupt learning and cause memory loss,” Gomez-Pinilla said.

What You Do To Your Body, You Do To Your Brain

The good news is that the omega-3 fatty acid DHA given to the other group of rats prevented the drop in brain function suffered by the first group.  In fact, they were also insulin sensitive.  It seems that adding the omega-3s to the rat’s diet protected them against the harmful effects of fructose.

“Eating a high-fructose diet over the long term alters your brain’s ability to learn and remember information. But adding omega-3 fatty acids to your meals can help minimize the damage.”

It’s hard to find a study that supports the Bulletproof Diet more than this one.  Not only did it show that fructose damages your brain function, it also shows that DHA protects your brain.  The Bulletproof Diet supplies ample high quality omega-3s from grass-fed meat, wild-caught/low-mercury seafood, select fish, fish oil and krill oil supplements.  If you overdo your fructose intake for a day, these fats will help limit the damage.  On the other hand, if you aren’t consuming enough omega-3s, you’re going to be more sensitive to the negative effects of fructose.

Perhaps the greatest part of this study was how it further validated another key tenet of the Bulletproof Diet – that health is both mental and physical, and what you eat influences both.  As Dr. Gomez-Pinilla said:

“Our study shows that a high-fructose diet harms the brain as well as the body. This is something new.”

To some people, the idea that what you eat affects your brain function is like saying what you wear affects your gas mileage – the two variables are not meaningfully related.  This study shows that eating a lot of fructose decreases your mental performance, and that this can be partially prevented with omega-3s.  If you want to do everything you can to maximize your brainpower, you should limit fructose to less than 25 grams per day.  You should also aim to consume enough DHA from Bulletproof sources like high quality fish and krill oil supplements.  What you eat affects more than your waistline, it also affects who you are.

“Our findings illustrate that what you eat affects how you think.”

If you want to think clearly and be smarter, eat the Bulletproof Diet.