Researchers at the University of Auckland went looking for one thing in a familiar New Zealand fruit and found another. They wanted to know whether daily feijoa powder could help adults with prediabetes lose more weight or lower blood sugar during a weight-loss program. Six months later, neither result gave them much to celebrate.
But another number caught their attention.
Feijoas are the kind of fruit New Zealanders share by the boxful each autumn, even though much of the world barely knows them. The unexpected finding has given scientists a fresh reason to look inside. It also comes amid efforts to find a bigger market for a fruit that doesn’t travel well.
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The catch matters: this was an early clinical result, not proof that feijoas lower blood pressure. The trial wasn’t designed to answer that question. Its most interesting discovery was the one researchers hadn’t gone looking for.
What the Trial Actually Tested
The study asked whether feijoa powder could add anything to a weight-loss program.
The trial, called FERDINAND, enrolled 97 adults with prediabetes or elevated blood sugar at the university’s Human Nutrition Unit. Each mixed about 1 gram of whole-fruit feijoa powder or a placebo into breakfast food or water. The branded powder was called Feiolix.
Everyone followed a weight-loss program: free meal replacements for two months, then four months focused on keeping the weight off.
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Researchers wanted to see whether feijoa offered an extra edge on weight and blood sugar, a marker of diabetes risk. Compared with the placebo, it didn’t. Participants could still lose weight through the program, but the powder added nothing meaningful to either result.
The Number That Moved
It showed up in the top number of a blood pressure reading.
That’s systolic pressure, the force of blood against artery walls when the heart contracts. It improved more in participants taking feijoa powder than in those given the placebo.
“It’s not what we set out to find but it’s interesting and certainly warrants more research,” said Dr Ibrahim Mohamed of the Human Nutrition Unit.
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The university didn’t specify the size of the improvement, and the finding wasn’t consistent across all analyses.
Why it happened remains unclear. Feijoa contains polyphenols, flavonoids, vitamin C, and abscisic acid, compounds with potential antioxidant, anti-inflammatory, and metabolic effects. None has been identified as the cause.
Related: The Surprising Superfoods That Boost Energy and Mood
Why Nobody Is Calling It a Breakthrough
A promising result from a modest trial is far from a recommendation.
The authors say larger studies are needed to understand the powder’s possible contribution to blood pressure. No follow-up trial has been announced. The university also doesn’t say how many participants had high blood pressure or were taking medication.
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Importantly, the trial tested a branded powder during a structured weight-loss program, not whether fresh feijoas would work the same way.
An earlier short-term study in Iran suggested benefits for people with type 2 diabetes. The Auckland team calls FERDINAND the first long-term human trial of feijoa powder supplementation. For now, its blood pressure finding raises a question rather than answering it.
The Export Question Behind the Research
The money behind the trial came with an export goal attached.
New Zealand’s High-Value Nutrition National Science Challenge funded the trial to help boost health-food exports through scientifically validated health claims. Anagenix Ltd. supplied the powder, while AgResearch, the Malaghan Institute and Plant and Food Research collaborated with the university.
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Feijoas spoil too quickly for the global success New Zealand has enjoyed with apples and kiwifruit. As of May 2025, roughly 100 commercial growers supplied almost entirely the domestic market.
Brent Fuller of the New Zealand Feijoa Growers Association explained why: “They’ll keep in the chiller for two or three weeks, but that’s about it.” Work to extend shelf life continues, but no solution has been announced.
A Fruit People Give Away
Image Credit: vadimserebrenikov/123RF
In New Zealand, some people take pride in never having paid for one.
Every autumn, feijoas appear in boxes outside homes, office breakrooms and neighborhood Facebook groups. Wellington resident Diana Ward-Pickering says she gave away thousands from five backyard trees in one season.
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For all that local affection, feijoa isn’t native to New Zealand. It comes from the Brazilian highlands, Uruguay and a corner of Argentina. How it reached New Zealand remains a mystery. Fans love the flavor; detractors find it gritty, soapy or sour.
That attachment travels. During a 2013 passion-fruit shortage, New Zealand suppliers added a few hundred kilograms of feijoas to an Australian importer’s order. Homesick New Zealanders bought them within a week. The importer, Rohan Bicknell, now runs the online store Feijoa Addiction and, as of 2024, had 32 backyard trees and a 1,000-tree orchard.
Where Americans Come In
In parts of California, it’s in season right now.
In the US, feijoa is called pineapple guava. It thrives in California’s Sacramento Valley, where several farmers’ markets carry it from late September through December. The flavor recalls pineapple, guava, and strawberry. Ripe fruit can smell like bubblegum, with a jellylike center and slightly grainy flesh near the skin.
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Even the flowers have appeal. UC Davis plant scientist Alessandro Ossola says the edible petals taste like a jelly bean. Sacramento Tree Foundation arborist Stephanie Robinson planted 10 trees as a backyard privacy screen and harvested up to 30 gallons of fruit in one season.
Have you ever picked up a feijoa at a farmers’ market? What did you think of the flavor?
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