Fructose is the sugar found naturally in fruit, where its effects are mediated by fruit’s high fiber content and by its other positive nutritional aspects.. However, Americans get most of their fructose intake from processed foods sweetened with high-fructose corn syrup (HFCS). HFCS is a cheap liquid sweetener made from corn starch. It is also used in the production of sweetened drinks, syrups, honey and many desserts. It’s even in baby food. In fact, the Department of Agriculture (USDA) estimates each American consumed approximately 27 pounds of high-fructose corn syrup in 2014.
Despite its widespread use, this sweetener is not safe for human consumption. A number of diseases, from diabetes to cardiovascular disease, to Alzheimer’s disease to attention deficit hyperactivity disorder, have been linked to changes in genes in the brain. A new study from University of California Los Angeles has found that HFCS can damage hundreds of those genes, paving the way for those health conditions.
The researchers also discovered a positive fact: the omega-3 fatty acid called docosahexaenoic acid, or DHA, apparently reverses the genetic damage caused by fructose. Xia Yang, senior author of the study and a UCLA assistant professor of integrative biology and physiology, says:
DHA changes not just one or two genes; it seems to push the entire gene pattern back to normal, which is remarkable, and we can see why it has such a powerful effect.
DHA is present naturally in the membranes of our brain cells, but in quantities too small to actually fight disease. In order to have a supply of DHA adequate to repair genes, we have to get enough DHA in our diet, says Fernando Gomez-Pinilla, a UCLA professor of neurosurgery and of integrative biology and physiology, and co-senior author of the paper.
DHA makes the synapses in the brain stronger, and it enhances learning and memory. It is available from wild salmon (but not farmed salmon) and to a lesser degree, from other fish and fish oil, as well as walnuts, flaxseed, and fruits and vegetables.
The researchers trained rat subjects to escape from a maze, then they divided the rats into three groups. For the following six weeks, one group drank water with an amount of fructose equivalent to drinking a liter of soda every day. The second group was fed fructose water, along with a diet high in DHA. The third group was given water without fructose and no DHA.
When the six weeks was over, the rats were put through the maze again. Rats in the first group navigated the maze approximately half as fast as the rats in the third group, leading researchers to believe their memories had been impaired. The rats in the second group, however, performed similarly to rats in the third group, suggesting the DHA had mitigated the harmful effects of the fructose.
There were other significant findings. The rats fed a high-fructose diet had much higher glucose, triglycerides and insulin levels than did groups two and three. In human beings, elevated blood sugar, triglycerides and insulin levels are implicated in obesity, diabetes, and numerous other diseases.