As we wrote a few days ago, according to an animal study done in 2002 Olive Leaf Extract increases the concentration of thyroid hormone. This suggests that Olive Leaf Extract is a suitable slimming supplement. Two years ago Australian researchers at the University of Queensland did a study in which this supplement did indeed break down a specific type of body fat.
The researchers fattened a group of male rats for 16 weeks. The animals were given drinking water with glucose and feed with extra fat. [HCHF] A control group ate normally. [CS] In the last 8 weeks of the trial, both half of the experimental group and half of the control group were given feed that consisted of 3% of Olive Leaf Extract.
The supplement considerably reduced the growth of stomach fat, as you can see in the figure below. Olive Leaf Extract caused weight loss only in rats that had been given a limited amount of normal feed.
One possibility is that Olive Leaf Extract inhibits the growth of the fat layers in the stomach so that other fat reserves can grow more quickly. That is positive because it is stomach fat that produces inflammatory proteins that can increase the chance of such illnesses as diabetes, heart and vascular disease and some forms of cancer.
A second possibility (that doesn't exclude the first) is that Olive Leaf Extract enhances the absorption of nutrients in muscle cells. Adiponectin quickly comes to mind, but the Australians didn't study this.
The researchers were especially charmed by the findings that are summarised below. Olive Leaf Extract lowers the concentration of triglycerides in the fattened rats, inhibits the growth of the left ventricle in the heart and protects the liver against necrosis. Click for a larger figure.
"The results of this study demonstrate that treatment of diet-induced metabolic syndrome in rats with Olive Leaf Extract attenuated the metabolic, as well as structural and functional, changes in the heart and liver without decreasing blood pressure", the Australians concluded. "We propose that Olive Leaf Extract decreased cardiac and hepatic injury through the antioxidant and antiinflammatory effects of polyphenols, mainly oleuropein and hydroxytyrosol."
The research was funded by the Australian Dr Red Nutraceuticals, a manufacturer of supplements containing vegetable extracts. [drred.com.au]
J Nutr. 2010 May;140(5):946-53.