New Health Benefits From Olive and Avocado Oil

An unsaturated fat found in abundance in olive, avocado oil and other "healthy" unsaturated fats has yet another benefit: it helps keep the body satisfied to prolong the time between meals.

A new study in the October Cell Metabolism, a publication of Cell Press, reveals that once this type of fat, known as oleic acid, reaches the intestine, it is converted into a lipid (oleoylethanolamide, or OEA) that wards off the next round of hunger pangs. The researchers said it may be the first description of an ingredient in food that directly provides the raw materials for the proper function of the endocrine system.

The findings in rats may yield insight into the precise dietary makeup of fat and plant protein for optimal hunger control, the researchers said. The newly discovered signaling pathway might also be tapped into with nutritional supplements designed to control appetite by supplementing OEA levels or blocking its breakdown. Similarly, in conditions where people don't eat enough, the researchers speculate that treatments targeting this system might improve the appetite.

Importantly, diets high in processed foods that are riddled with acidic saturated fats that might throw a wrench into this system of metabolic control, the researchers said.

"Eating is one of the most important things animals do," said Daniele Piomelli of the University of California, Irvine. "This is just one of many things that control it. That said, a system like this could be forced to inactivation by inappropriate feeding," he said, noting that saturated fats lack in oleic unsaturate fat.

While such diets may lead people to overeat, Piomelli said it will also be of interest to see if this mechanism may be defective in some who tend to eat in excess.

Previous studies had shown that feeding stimulates cells in the intestinal lining to produce OEA, which, when administered as a nutritional supplement, decreases meal frequency by engaging receptors called peroxisome proliferator-activated receptors a (PPARa).

Piomelli's team now reports that infusion of olive or avocado oil into the small intestine stimulates the release of OEA, whereas infusion of protein or carbohydrate does not.