Fructose makes rats dumber. What sugars should we avoid?
The problem with the LA Times article is that the study doesn't actually compare sugars, it compares combinations of fructose and n-3. It's too bad, actually, that they didn't add in glucose also, I'm genuinely curious what the effects on cognition would be vs fructose. Nevertheless it is an interesting study.
I would love to give this study the Petro Dobromylskyj treatment, but since I lack the knowledge and motivation I will just give it the brand X treatment.
Okay, so here's the abstract:
We pursued studies to determine the effects of the metabolic syndrome (MetS) on brain, and the possibility of modulating these effects by dietary interventions. In addition, we have assessed potential mechanisms by which brain metabolic disorders can impact synaptic plasticity and cognition. We report that high-dietary fructose consumption leads to an increase in insulin resistance index, and insulin and triglyceride levels, which characterizeMetS. Rats fed on an n-3 deficient diet showed memory deficits in a Barnes maze, which were further exacerbated by fructose intake. In turn, an n-3 deficient diet and fructose interventions disrupted insulin receptor signalling in hippocampus as evidenced by a decrease in phosphorylation of the insulin receptor and its downstream effector Akt.We found that high fructose consumption with an n-3 deficient diet disrupts membrane homeostasis as evidenced by an increase in the ratio of n-6/n-3 fatty acids and levels of 4-hydroxynonenal, a marker of lipid peroxidation. Disturbances in brain energy metabolism due to n-3 deficiency and fructose treatments were evidenced by a significant decrease in AMPK phosphorylation and its upstream modulator LKB1 as well as a decrease in Sir2 levels. The decrease in phosphorylation of CREB, synapsin I and synaptophysin levels by n-3 deficiency and fructose shows the impact of metabolic dysfunction on synaptic plasticity. All parameters of metabolic dysfunction related to the fructose treatment were ameliorated by the presence of dietary n-3 fatty acid. Results showed that dietary n-3 fatty acid deficiency elevates the vulnerability to metabolic dysfunction and impaired cognitive functions by modulating insulin receptor signalling and synaptic plasticity.tl;dr: n-3 no fructose did the best, n-3 deficient diet with fructose did the worst.
See this? This is my shocked face. Still, it's easy to have one's preconceptions confirmed, and it's easy to be less than skeptical of studies that confirm them.
Interesting that the n-3/fructose rats were the fattest with the highest caloric intake.
And now we get to the meat of things: