Go Nuts!

Have you ever noticed that some of your strongest food memories are of rich, fat laden meals shared with family and friends? According to new research, this may not be a coincidence. A study published last week in the Proceedings of the National Academy of Sciences demonstrates that digesting fatty foods enhances memory consolidation using the same neural pathway as emotional learning.

This finding has far reaching implications for cognitive therapies to fight over-eating, but may also suggest new, easy to implement strategies for memory enhancement. Pistachios anyone?

In the study, rats being trained on memory tasks were administered a substance called oleoylethanolamide (OEA) that normally increases in the gut after the ingestion of dietary fat (not carbohydrate or protein). Several days later, the rats given OEA performed better on the tasks than rats that were not, demonstrating enhanced learning.

To determine the neural pathway involved in this effect, the researchers chemically blocked signaling in the region of the brain that receives neural inputs from the gut (solitary nucleus), which abolished the effect of OEA. Next they selectively blocked neural transmission between this region and another region of the brain that has been shown to be critical for emotional learning (amygdala). This also eliminated the memory enhancement effect of OEA, indicating that emotional memory and memory enhancement from fatty food ingestion share the same neural network.

These findings may partially explain the emotional component that is often associated with chronic over-eating, something that frequently involves learned habits triggered by emotional situations.

However, OEA does more than enhance memory. It is also critical in feelings of satiety after a meal (decreasing hunger) and has been implicated in controlling body weight. Is it possible this new information could be harnessed for the power of good?

Low-fat diets have proved to be a colossal failure for both health and weight loss, partially because they encourage over-consumption of starchy (usually refined) carbohydrates. Moreover, vegetable and fish oils are protective against many chronic diseases that plague Western culture. Regularly seeking healthy fats in your diet can help control hunger, promote weight loss and lower risk of disease. But it now seems that healthy fats could also be a useful tool in overcoming emotional eating, a problem more complex than the standard weight gain that comes from 21^st century living.

Another interesting corollary of this study is that fat (specifically oleic acid, a healthy fat found predominantly in olive oil and nuts) may enhance learning and memory. Since the benefits of OEA were only evident when it was administered at the time of or immediately after training, the next time you study or prepare for a presentation you might want to have some nuts around to snack on. Almonds, cashews, hazelnuts, macadamia nuts, peanuts, pecans and pistachios are highest in oleic acid.

Are you interested in foods that could provide cognitive enhancement?

Tags: fat, learning, memory, neural network, nuts, pistachios, PNAS, Synapse, unsaturated fat

High blood sugar levels are known to accelerate aging and decrease longevity in many different species. Now it seems blood sugar may also be tied to how well you keep your memory as you age.

A new study published in the December issue of the Annals of Neurology examined the effect of high blood sugar on the region of the brain responsible for memory formation, the hippocampus. Researchers examined patients with either diabetes or stroke (in other, non-hippocampus, parts of the brain) and determined that both groups had defects in the hippocampus compared to normal patients, but the problems were in different hippocampal subregions.

What does this mean for you?

Tags: Annals of Neurology, blood sugar, memory