Comvita shares hit 5-year high

Comvita's olive leaf extract may have benefits for some men at risk of diabetes. Photo / Supplied

Shares of Comvita rose 2.7 per cent to a five-year high of $3.80 after a company statement detailed the results of medical research, yet to be peer-reviewed, showing its olive leaf extract boosts the effectiveness of insulin in overweight, middle-aged men at risk of diabetes.

Undertaken by the Liggins Institute, a medical research centre of at the University of Auckland, the research examined "a range of complex health outcomes, including insulin responses among those trial participants who took fresh olive leaf extract for 12 weeks."

The research project concluded that the fresh olive leaf extract "improves the way insulin is secreted and works in overweight men," the company said in a statement to the NZX.

The research has been submitted to an unnamed "highly prestigious, international medical journal".

Detailed comment on the research is prohibited by the requirements of the peer review process, which the research must pass to be published.

Using 45 overweight men with an average age of 46.6, the trial found taking the extract "was associated with a 15 per cent improvement in insulin action, and a 28 per cent improvement in insulin secretion."

It found no significant changes in other areas tested, including "lipid profile, ambulatory blood pressure, body composition, carotid intimal thickness, or parameters of liver function."

Comvita last year saw off a takeover bid from Cerebos Greggs, a global food manufacturer, pitched at $2.50 a share, which was rejected by directors, who put a value range of $3.40 and $4 a share.