You’ve probably heard the adage, “you are what you eat.” According to scientists at UCLA, what you eat may also affect how you use your noodle. In fact, too much of the sweet stuff – specifically, fructose – seems to impair learning and memory. The good news is that you can exercise damage control by avoiding high-fructose corn syrup (surprise!) and increasing your intake of omega-3 fatty acids.
Contrary to the “Changing the Conversation about High Fructose Corn Syrup” media campaign initiated by the Corn Refiners Association in 2008, not all sugar is created equal. Further, high-fructose corn syrup (HFCS) isn’t “natural” or simply “okay to eat in moderation,” as these advertising claims suggest. In fact, only plants and foods picked off a vine or tree (i.e., fruits and vegetables) contain truly natural sugars. You might remember from your high school biology class that the body uses these simple sugars to manufacture energy to fuel cells and organs. As an added bonus, these foods also provide potent antioxidants to ward off disease, including cancer. However, because HFCS is cheap to synthesize, it lands in commercially processed food as a preservative and sweetening agent. The fact that eating too much sugar — especially fructose — makes you fat isn’t new, but the finding that too much hurts the brain is somewhat of a surprise. One reason for this may be related to the role of insulin in synaptic function, levels of which tend to decrease with high fructose intake.
Why HFCS is Not Smart Choice
HFCS has been a source of debate between natural health advocates and the companies that produce and sell the stuff, namely the various members of the CRA. In contrast to all the marketing spin, HFCS doesn’t it live up to the “sugar is sugar, the body can’t tell the difference” litmus test the CRA created. Corn syrup, the precursor to HFCS, is a liquid starch of maize composed of malt sugar and various oligosaccharides, which simply means multiple monosaccharides, or simple sugars. Fruits and vegetables contain varying degrees of fructo-oligosaccharides (FOS), commonly referred to as plain fruit sugars. This is the stuff that Mother Nature made to make life sweeter that is also found in sugar beets, cane sugar and honey.
HFCS, however, is a turbo-charged sweetener that has undergone enzymatic processing to degrade most of the glucose in the syrup into fructose. The result is a highly processed substance that the American Medical Association suspects is a major contributor to obesity and diabetes. (1) In addition, HFCS may contain synthetic and/or genetically modified ingredients and, according to a 2012 study published in “Clinical Epigenetics,” appears to negatively affect metabolic functions in autistic children that are necessary to eliminate heavy metals from the body. (2)
Here’s another bitter truth to swallow: The U.S. Department of Agriculture estimates that the average American consumes about 35 pounds of high-fructose corn syrup every year from soft drinks, cereals, fruit juices, condiments, baked goods, canned fruit goods and even baby food. (4)
Proof is in the Rat Race
The UCLA scientists challenged two groups of rats to learn to run a specific course through a maze, which was equipped with visual cues but only one exit and several distracting dead-end holes. After two training sessions per day for five days, the maize-efficient rats were given a diet that included standard rat chow and a fructose solution to drink instead of plain water in both groups, but one group was treated to a supplement of flaxseed oil and docosahexaenoic acid (DHA). After six weeks, it was time to revisit the maze. The researchers found that the group that received omega-3 and DHA ran the course more accurately and much faster, while their sugar-loaded counterparts showed signs of decreased neurotransmission in their brains. What’s more, these rats also developed insulin resistance, a key factor in the development of type II diabetes. Unable to utilize this hormone properly in the brain, these rats evidenced impaired neural signaling and memory loss – in just six weeks. (3) Dr. Fernando Gomez-Pinilla, one of the study authors, suspects that fructose may inhibit the ability of insulin to regulate sugar utilization in brain cells involved in processing thoughts and emotions. The study, funded by the National Institute of Neurological Disorders and Stroke, was published in the May 15, 2012 issue of “Journal of Physiology.” (4)
Your Brain on Sugar
Obviously, more research is needed before extrapolating the findings of this study to humans. Still, it would be reasonable and prudent to presume that similar limiting effects in cognitive function may occur in people who indulge in too many sweets of the processed variety. At the very least, the potential long-term implication of habitually drinking beverages and eating processed foods sweetened with HFCS is something to think about. Gomez-Pinilla suggests satisfying your sweet tooth with Greek yogurt and berries, or even the occasional piece of dark chocolate. A supplement that delivers one gram of DHA per day is also recommended, as well as increasing your intake of foods high in omega-3 such as nuts, seeds and salmon. (3)