Collaborative study finds parallels between the addictive qualities of fructose and cocaine
The negative health effect of sugar, specifically fructose, have long been known, but a University of Guelph-led study showed just how addictive this sugar can be. Researchers at U of G and Rockefeller University in New York City studied the effects of various types of sugar consumption in.
They allowed the rats to self-administer pellets of high-fructose corn syrup (HFCS), sucrose, and saccharin, and then conducted three experiments: one to measure effects on brain activity, another that measured genes related to addiction, and the third to study fatty acid levels. The recent study found similarities in brain chemistry between rats fed pellets with higher levels of fructose to those that had been fed cocaine in a 2013 study.
The cocaine study found correlations between the rats’ self-administration of Oreos and their self-administration of the drug.
Professor Francesco Leri of Guelph’s Department of Psychology was a researcher in both of these studies.
Regarding the 2015 sugar study, he explains in a press release, “We found that those rats exposed to HFCS consumed fewer calories overall but, surprisingly, their livers displayed a higher concentration of a polyunsaturated fatty acid that can lead to increased inflammation.”
“Across all experiments, we observed that it took less exposure to sugars with a higher fructose ratio to lead to both neural and physiological responses associated with addictive and metabolic diseases.”
The researchers theorized that fructose has less of a stimulating effect on brain regions such as the hypothalamus that regulate food intake. These regions of the hypothalamus synthesize and release peptides that help the body regulate its appetite.
Interestingly, the researchers noted that the rats did not seem to have a taste preference for specific types of pellets, regardless of the fructose content. Their self-administration of the saccharin pellets was significantly lower, likely because of the lack of caloric content, but they seemed to enjoy these pellets just as much.
The rats also did not display an increase in food intake following consumption of the pellets.
Though HFCS was the only high-fructose solution studied, the results raise questions about the effects of other sugary substances with greater ratios of fructose.
HFCS isn’t pure fructose—in fact, a substantial portion is still made up of glucose, with a ratio of 55 per cent fructose to 42 per cent glucose.
This isn’t that far off from table sugar, a disaccharide (two-carbon) sugar that has one glucose linked to each fructose molecule, resulting in a 50/50 ratio.
In comparison, honey also typically has a higher fructose ratio, though the exact ratios vary depending on the type of honey. For instance, one study found clover honey to have a fructose-glucose ratio of 1.09, while tupelo had a sizeable 1.54 ratio.
And agave nectar, often promoted as a natural, vegan alternative to honey, is typically made up of a staggering 90 per cent fructose.
Therefore, the U of G study results may call into question the potential impacts of these “healthier” natural foods when analyzed via their biochemical ratios alone. However, more research is needed to study their specific effects.
For now, it’s probably a safe bet to limit general sugar intake. Not the best news for those with a sweet tooth, but your liver and your waistline will thank you.