I thought this was interesting, because it talks about sugar and spatial memory:
The Effects of a High-Energy Diet on Hippocampal Function and Blood-Brain Barrier Integrity in the Rat
Cognitive impairment and Alzheimer's disease are linked with intake of a Western diet, characterized by high levels of saturated fats and simple carbohydrates. In rats, these dietary components have been shown to disrupt hippocampal-dependent learning and memory processes, particularly those involving spatial memory. Using a rat model, the present research assessed the degree to which consumption of a high-energy (HE) diet, similar to those found in modern Western cultures, produces a selective impairment in hippocampal function as opposed to a more global cognitive disruption. Learning and memory performance was examined following 90-day consumption of an HE-diet in three nonspatial discrimination learning problems that differed with respect to their dependence on the integrity of the hippocampus. The results showed that consumption of the HE-diet impaired performance in a hippocampal-dependent feature negative discrimination problem relative to chow-fed controls, whereas performance was spared on two discrimination problems that do not rely on the hippocampus. To explore the mechanism whereby consuming HE-diets impairs cognitive function, we investigated the effect of HE-diets on the integrity of the blood-brain barrier (BBB). We found that HE-diet consumption produced a decrease in mRNA expression of tight junction proteins, particularly Claudin-5 and -12, in the choroid plexus and the BBB. Consequently, an increased blood-to-brain permeability of sodium fluorescein was observed in the hippocampus, but not in the striatum and prefrontal cortex following HE-diet access. These results indicate that hippocampal function may be particularly vulnerable to disruption by HE-diets, and this disruption may be related to impaired BBB integrity.
(Via this page)
The 2010 Dietary Guidelines for Americans say it is acceptable for some people to consume up to 19% of calories from added sugars, and the Institute of Medicine permits up to 25% of total calories from added sugars. In contrast, the World Health Organization recommends that added sugars should make up no more than 10% of an entire day's caloric intake, with a proposal to lower this level to 5% or less for optimal health. Such levels would be more in line with what the authors would recommend and similarly restrictive to existing American Heart Association (AHA) recommendations--to consume no more than six teaspoons (24 grams) of sugar per day for women and no more than nine teaspoons (36 grams) of sugar per day for men.
- High blood sugar levels linked to memory loss
- Binging on Sugar Weakens Memory, UCLA Study Shows
- High blood sugar may affect memory in some people
(Edit: I merged the other post below.)
This is interesting:
Eating High Levels Of Fructose Impairs Memory In Rats
Researchers at Georgia State University have found that diets high in fructose — a type of sugar found in most processed foods and beverages — impaired the spatial memory of adult rats.
Another research group has shown in hamsters that insulin resistance can affect the hippocampus, a part of the brain critical for learning and remembering facts and events. Parent’s team is examining whether the hippocampus of the memory-impaired rats became resistant to the hormone.