Sugar makes you stupid: Study shows high-fructose diet sabotages learning, memory

Attention, college students cramming between midterms and finals: Binging on soda and sweets for as little as six weeks may make you stupid.

A new UCLA rat study is the first to show how a diet steadily high in fructose slows the , hampering memory and learning — and how omega-3 can counteract the disruption. The peer-reviewed Journal of Physiology publishes the findings in its May 15 edition.

"Our findings illustrate that what you eat affects how you think," said Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA and a professor of integrative biology and physiology in the UCLA College of Letters and Science. "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."

While earlier research has revealed how fructose harms the body through its role in diabetes, obesity and fatty liver, this study is the first to uncover how the sweetener influences the brain.

The UCLA team zeroed in on high-fructose corn syrup, an inexpensive liquid six times sweeter than cane sugar, that is commonly added to processed foods, including soft drinks, condiments, applesauce and baby food. The average American consumes more than 40 pounds of high-fructose corn syrup per year, according to the U.S. Department of Agriculture.

"We're not talking about naturally occurring fructose in fruits, which also contain important antioxidants," explained Gomez-Pinilla, who is also a member of UCLA's Brain Research Institute and Brain Injury Research Center. "We're concerned about high-fructose corn syrup that is added to manufactured food products as a sweetener and preservative."

Gomez-Pinilla and study co-author Rahul Agrawal, a UCLA visiting postdoctoral fellow from India, studied two groups of rats that each consumed a fructose solution as drinking water for six weeks. The second group also received omega-3 fatty acids in the form of flaxseed oil and docosahexaenoic acid (DHA), which protects against damage to the synapses — the chemical connections between brain cells that enable memory and learning.

"DHA is essential for synaptic function — brain cells' ability to transmit signals to one another," Gomez-Pinilla said. "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."

The animals were fed standard rat chow and trained on a maze twice daily for five days before starting the experimental diet. The UCLA team tested how well the rats were able to navigate the maze, which contained numerous holes but only one exit. The scientists placed visual landmarks in the maze to help the rats learn and remember the way.

Six weeks later, the researchers tested the rats' ability to recall the route and escape the maze. What they saw surprised them.

"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."

The DHA-deprived rats also developed signs of resistance to insulin, a hormone that controls blood sugar and regulates synaptic function in the brain. A closer look at the rats' brain tissue suggested that insulin had lost much of its power to influence the brain cells.

"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.

He suspects that fructose is the culprit behind the DHA-deficient rats' brain dysfunction. Eating too much fructose could block insulin's ability to regulate how cells use and store sugar for the energy required for processing thoughts and emotions.

"Insulin is important in the body for controlling blood , but it may play a different role in the brain, where insulin appears to disturb and ," he said. "Our study shows that a high-fructose harms the brain as well as the body. This is something new."

Gomez-Pinilla, a native of Chile and an exercise enthusiast who practices what he preaches, advises people to keep fructose intake to a minimum and swap sugary desserts for fresh berries and Greek yogurt, which he keeps within arm's reach in a small refrigerator in his office. An occasional bar of dark chocolate that hasn't been processed with a lot of extra sweetener is fine too, he said.

Still planning to throw caution to the wind and indulge in a hot-fudge sundae? Then also eat foods rich in omega-3 fatty acids, like salmon, walnuts and flaxseeds, or take a daily DHA capsule. Gomez-Pinilla recommends one gram of DHA per day.

"Our findings suggest that consuming DHA regularly protects the brain against fructose's harmful effects," said Gomez-Pinilla. "It's like saving money in the bank. You want to build a reserve for your brain to tap when it requires extra fuel to fight off future diseases."

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TS1
5 / 5 (1) May 15, 2012
Brings to mind two major differences between food in USA and Europe (well at least the northern Europe & Switzerland that I have experience from).

The first is that food here in USA is often quite sweet. It is as if they ignored all other possible flavors and issues and just thought about making it sweet (hoping perhaps that people will not care about anything else).

The second is that the food stuff here in US is more often sweetened with High Fructose Corn Syrup, and it is just BS to claim that "sugar is sugar".
sstritt
1 / 5 (1) May 15, 2012
So makes you fat AND stupid!
LariAnn
1 / 5 (1) May 15, 2012
The article should be titled "High Fructose Corn Syrup Makes You Stupid"; the FDA folks that approved it must have been using it for a while in order to make such a decision. It's in everything now so it is very hard to find a good soda or fruit juice without it. Thanks, FDA!
HealingMindN
5 / 5 (1) May 15, 2012
Yet another culture shock: High Fructose Memory.
ziphead
1 / 5 (1) May 15, 2012
"Stupid is what stupid does"
Or eats.
verkle
not rated yet May 15, 2012
Doesn't the article only mention tests done on rats? Where is the follow on study with humans? There doesn't seem to be any proof that the same holds for humans. Too early judgment.

nuge
not rated yet May 16, 2012
I'm sure this effect is trumped by the damage that people willingly cause to their own brains with alcohol.
kevinrtrs
not rated yet May 16, 2012
Is this still part of the war between the high fructose manufacturers and the sugar[sucrose] manufacturers?
88HUX88
not rated yet May 16, 2012
and what about a control group of rats that did not consume fructose, did not have DHA supplements and only drank water with standard rat chow; how did they do?
antialias_physorg
not rated yet May 16, 2012
Doesn't the article only mention tests done on rats? Where is the follow on study with humans?

It's going on all around you - and has been for the better part of the last 50 years.
wwqq
not rated yet May 16, 2012
[...]it is just BS to claim that "sugar is sugar".


Oh for the love of...

This is just tiresome. Sucrose, AKA cane sugar, AKA beet sugar, contains just as much fructose as does HFCS.

Get it through your thick skulls; if fructose is harmful, so is "real" sugar.
antialias_physorg
3 / 5 (2) May 16, 2012
Anyways, what happens in your body is always the same: All long chain sugars (fructose, glucose, whatever) get broken down into mono-sugars. Only THEN can they pass throug the cell walls in the intestine.
Eikka
not rated yet May 16, 2012
"We're concerned about high-fructose corn syrup that is added to manufactured food products as a sweetener and preservative."


What they did not tell, is that ordinary cane sugar or sucrose gets catalyzed by acidity in things like sodas, and becomes essentially the same thing as HFCS because sucrose is composed of 50% fructose and 50% glucose monosaccharides.

LagomorphZero
not rated yet May 16, 2012
88HUX88 got it right. This article is very badly written, and done so intentionally.

Sugar was not the object under test in the described experiment, Omega-3/DHA was. Sugar was applied to both the control and test populations, so no conclusion could be drawn from the described experiment about how sugar affects rats.
julianpenrod
1 / 5 (1) May 17, 2012
How revealing that so many here who are evidently little more than puppets for the New World Order agenda failed to see that "high fructose corn syrup" is not "sugar". It's not even "fructose" notice! "High fructose corn syrup" has large amounts of fructose, but fructose does not occur in liquid form! There are many other ingredients in "high fructose corn syrup" that are alien to the sugar process! By definition, "high fructose corn syrup" initially contains mostly or only sucrose, but some of that is converted by enzyme action into fructose. If you think, among other things, all those enzynes are necessarily removed before sale, you may be as self destructively stupid as the NWO needs you to be!
EverythingsJustATheory
not rated yet May 17, 2012
NWO, wasn't that the name of Hulk Hogan's wrestling crew in the 90s?
ean
not rated yet May 18, 2012
Anyways, what happens in your body is always the same: All long chain sugars (fructose, glucose, whatever) get broken down into mono-sugars. Only THEN can they pass throug the cell walls in the intestine.


Long chain sugars (polysaccharides) are starch, cellulose, etc. Fructose and glucose are simple sugars.
ryggesogn2
not rated yet May 19, 2012
Most computer geeks live on sugar.
ryggesogn2
not rated yet May 19, 2012
Sugar and other carbohydrates are the one food group humans can manufacture from fat and protein.
Govt promotes sugar and starch via the food pyramid to subsidize grain farmers.
updog
1 / 5 (1) May 20, 2012
There really is a big difference between high fructose corn syrup and sugar. HFCS can only be metabolized by cells in the liver, putting a strain on organs which support the liver and produce enzymes for it. This is probably why there is a quiet realization in the science community that pancreatic cancer, one of the deadliest cancers, is correlated with HFCS consumption.

Secondly, since the 1970's when corn subsidies started to make high fructose corn syrup a viable, cheaper alternative to cane sugar and soda makers gradually began replacing sugar with HFCS, diabetes rates have been increasing dramatically. You can almost see a lock-step correlation with diabetes rates and HFCS usage, and considering that HFCS inhibits satiety (keeps you from feeling full) and that diabetes is strongly related to metabolizing sugars, it isn't a big logical jump to think that this could be more than a coincidence.

Sugar might be bad for you, but HFCS slowly kills you. That's the difference.
Alcedine
not rated yet May 22, 2012
"HFCS can only be metabolized by cells in the liver, putting a strain on organs which support the liver and produce enzymes for it."

Both HFCS and sucrose are lysed in the intestine and transmitted as monosaccharides to the liver via the hepatic vein. Glucose can be used natively, while fructose must be (laboriously) converted to glucose. The only relevant number is the fructose fraction, and by that metric, the most commonly used HFCS and sucrose generally are afaik within ten percentage points of each other.

"Secondly, since the 1970's when corn subsidies started to make high fructose corn syrup a viable, cheaper alternative to cane sugar and soda makers gradually began replacing sugar with HFCS, diabetes rates have been increasing dramatically."

It was probably just cheaper, making the foods that contain it cheaper, making people consume more of them. Not to mention eating habits have probably deteriorated with the rise of a sedentary lifestyle.
wwqq
not rated yet May 25, 2012
JulianPernod,

The clue is in the name. High fructose corn SYRUP. Water is a polar solvent that disolves most sugars; maybe you have heard of it?

HFCS is glucose, fructose and WATER. If you eat sucrose it is rapidly hydrolyzed into glucose and fructose disolved in water. It's the same damn thing.
wwqq
not rated yet May 25, 2012
There really is a big difference between high fructose corn syrup and sugar. HFCS can only be metabolized by cells in the liver, putting a strain on organs which support the liver and produce enzymes for it.


So what is the difference? (hint: this is true of fructose from ANY source, including metabolism of sucrose)
wwqq
not rated yet May 25, 2012
Long chain sugars (polysaccharides) are starch, cellulose, etc. Fructose and glucose are simple sugars.


The glycemic index measures how fast carbohydrates are broken down into glucose and absorbed into the bloodstream.

The difference between white bread and pure glucose is negligible. On the relevant timescales the break down of "complex" starches into simple sugars is instantaneous.

The only barriers of major importance are mechanical ones. In pasta, starch grains are embedded in a matrix of protein; in fruit the sugars have to slowly leach out of fruit pulp; in rolled cerial flakes(e.g. müsli) the starch is partly protected by cellulose fiber.

The distinction between simple and complex sugars is not of importance here.
antialias_physorg
not rated yet May 25, 2012
The distinction between simple and complex sugars is not of importance here.

I'm not sure whether this is irrelevant. The insulin levels (or at least the dynamic of insulin release) associated with direct sugar uptake and uptake of complex carbohydrates is different.

Insulin acts on all sugars, and when no sugars are present anymore it will work on any other sugarlike substanc that it finds until depleted (this includes myelin covering of nerve fibers). So a massive overshoot of insulin release (e.g. due to consumption of HFCS and especially 'light' products with artificial sweeteners) is potentially more damaging than eating white bread.
Mike_Massen
not rated yet Jun 13, 2012
WHat ?