Harbingers of autumn and something of a Kiwi curiosity, feijoas may also soon provide an answer to the world’s Type 2 diabetes epidemic.
The humble fruit is the focus of a study committed to learning more about its possible diabetes-busting properties, thanks to funding through the National Science Challenge.
Researchers at the University of Auckland are setting up a six-month study focused on feijoas. They intend to give adults with elevated blood sugar a gram of whole fruit feijoa powder or a placebo every day.
Known as Ferdinand, the study requires participants to follow a low energy Cambridge weight-loss diet for eight weeks and to complete a four-month weight maintenance programme while also consuming the feijoa powder or a placebo.
The principal investigator, Associate Professor Jennifer Miles-Chan, said the fruit may contain helpful compounds particularly within its skin that include polyphenols and abscisic acid that may help reverse pre-diabetes symptoms including elevated blood sugar.
Polyphenols are compounds often found in fruit that can contribute to its flavour, and include the likes of tannins in tea.
They have been linked to bioactive compounds found in food that can improve health.
However, the science is in its early stages, with no recommendations for bioactives made yet in the human diet.
Abscisic acid has been shown to deliver anti-diabetic effects in mice, and has become popular in naturopathy circles.
“In theory, the feijoa powder will boost the benefits of weight loss, leading to improvements in blood sugar levels,” Miles-Chan said.
The Auckland study has been prompted by a short-term study in Iran that indicated benefits of feijoas for patients with Type 2 diabetes.
The study is aimed at individuals who are overweight and at risk of Type 2 diabetes but have not yet contracted it.
“We are really wanting to help those people who are on the borderline of developing diabetes to lower their risk, yet many people may not be aware their blood sugar levels are high,” Miles-Chan said.
She said the trial also brings the added appeal of receiving two months of free meals.
Supported by the High-Value Nutrition National Science Challenge (Ko Ngā Kai Whai Painga), the study is being conducted by the University’s Human Nutrition Unit in collaboration with AgResearch, the Malaghan Institute and Plant and Food Research.