Fatty acids may enhance obesity treatment

NEW YORK (Reuters Health) - Oleic acid empties from the stomach more slowly and suppresses appetite more potently than macadamia oil, results of a study suggest. Oleic acid also stimulates specific gastrointestinal hormones known to send fullness signals.

These findings, Dr. Tanya J. Little, from the University of Adelaide, South Australia, and colleagues say, could have application in obesity treatment.

Oleic acid, a so-called free fatty acid, is the main component of olive oil. Macadamia oil, a so-called "triacylglyceride," is the main constituent of vegetable oil and animal fats.

Little and colleagues studied nine healthy normal-weight men on three separate occasions to determine the effects in the gut and on appetite of 40 grams of acid oleic acid, 40 grams of the macadamia oil, and 600 mL 4 percent milk protein (the control substance).

They report in the journal Gastroenterology that oleic acid stayed in the stomach much longer than macadamia oil.

Moreover, hunger was less and fullness was greater after oleic acid when compared with milk protein and macadamia oil, and energy intake tended to be less as well.

Oleic acid also produced an earlier and more dramatic increase in circulating levels of the gut hormones CCK and PYY, relative to macadamia oil and milk protein.

In a written commentary, two researchers note that the potential importance of this finding is "considerable" as CCK and PYY are regarded as "major players" in inducing feelings of fullness.

Additional studies, note Drs. Michael Camilleri and Seth Sweetser of the Mayo Clinic College of Medicine, Rochester, Minnesota, "may lead to novel applications for obesity management."

SOURCE: Gastroenterology, November 2007.