Fats help memory last longer: Study

27-Apr-2009 - Last updated on 28-Apr-2009 at 11:15 GMT

Eating food that is rich in fat can trigger long-term memory formation, according to new research which could lead to new approaches for tackling obesity and eating disorders.

Researchers in the US looked at how dietary fats facilitate memory retention in rats and the results showed that eating fat-rich foods triggers memory consolidation of that activity, which could affect cravings.

Experts have defined a ‘craving’ as an intense desire to eat a particular food. It is a sensory memory that has to be matched in order to achieve satisfaction.

Some believe that understanding food cravings is key to successfully developing measures to counter the current obesity crisis, which is a major concern for the food industry.

The study was carried out by Daniele Piomelli, the Louise Turner Arnold Chair in Neurosciences, and UC Irvine’s James McGaugh.

Piomelli’s previous research identified how oleic acids from fats are transformed into a compound called oleoylethanolamide (OEA) in the upper region of the small intestine.

OEA sends hunger-curbing messages to the brain to increase feelings of fullness and in elevated levels, OEA can reduce appetite, produce weight loss and lower blood cholesterol and triglyceride levels.

Now, in this latest study, called “Fat-induced satiety factor oleoylethanolamide enhances memory consolidation” and published in the online edition of the Proceedings of the National Academy of Sciences, Piomelli and McGaugh discovered that OEA also causes memory consolidation.

This is the process by which superficial, short-term memories are transformed into meaningful, long-term ones.

Piomelli said it does this by activating memory-enhancing signals in the amygdala, part of the brain involved in the consolidation of memories of emotional events.

However, such memory enhancement may not be so beneficial because while OEA contributes to feelings of fullness after a meal, it could also engender long-term cravings for fatty foods, which when eaten in excess, can cause obesity.

Dietary fats are important for overall health, helping with the absorption of vitamins and the protection of vital organs.

Piomelli said: “OEA is part of the molecular glue that makes memories stick.

“By helping mammals remember where and when they have eaten a fatty meal, OEA's memory-enhancing activity seems to have been an important evolutionary tool for early humans and other mammals.

"Remembering the location and context of a fatty meal was probably an important survival mechanism for early humans.

"It makes sense that mammals have this capability."

It is also well established that stress hormones activated by emotional arousal enhance memories of cues associated with the arousal.

This suggests that hormonal and neural signals elicited by feeding might also enhance the consolidation of recent experiences.

The authors concluded: “Our results provide evidence that OEA enhances memory consolidation by activating noradrenergic transmission in the basolateral complex of the amygdala(BLA), a neuromodulatory mechanism that is critically implicated in the consolidation of emotional memories.”

Piomelli said drugs that mimic OEA are in clinical trials for triglyceride control and he is interested in learning whether they could improve consolidation in people with memory problems.

Source: Proceedings of the National Academy of SciencesDoi: 10.1073/pnas.0903038106

“Fat-induced satiety factor oleoylethanolamide enhances memory consolidation”

Authors: Patrizia Campolongoa, Benno Roozendaalb, Viviana Trezzac, Vincenzo Cuomoc, Giuseppe Astaritaa, Jin Fua, James L. McGaughb, and Daniele Piomellia.