Introducing orange capsicums to the menu would address deficiencies of a chemical compound which helps prevent Australia’s leading cause of blindness — but hardly any Australian farmers are growing them.
Research by the University of Queensland (UQ) has found orange capsicums are by far the richest source of the orange pigment zeaxanthin, a carotenoid which accumulates in the back of the eyes to protect against blue light and, therefore, macular degeneration.
Age-related macular degeneration is responsible for half of all cases of blindness in Australia, affecting one in seven people aged over 50 and one in three over 80.
Project leader Tim O’Hare, from the Queensland Alliance for Agriculture and Food Innovation, said zeaxanthin could reduce the development rate of age-related macular degeneration by 25 per cent.
“Your maculas are a very central part of your retina, so we use it to recognise people’s faces and to read and when we’re driving,” Dr O’Hare said.
“As you can imagine it makes life very difficult.”
Like taking 30 supplements
Zeaxanthin cannot be produced by the body, so it needs to be introduced through diet or supplements.
Dr O’Hare said the compound is found in other fruits and vegetables but only in very small amounts.
It is not found in any other capsicums, including yellow varieties.
“Orange capsicums are by far and wide the most generous source of zeaxanthin that you’ll find,” Dr O’Hare said.
In fact, one capsicum was found to contain zeaxanthin levels equivalent to 30 supplement tablets.
The daily recommended dose is 2mg, which amounts to eating between seven and 100 grams of orange capsicum.
Supply depends on demand
Unfortunately, Australian shoppers have difficulty finding orange capsicums at the greengrocers or in supermarkets.
North Queensland grower Carl Walker is among just a handful of farmers who have grown them in recent years, however he struggled to make a profit due to the high price of seeds.
“Orange capsicums are a lot harder to sell and the price of the seeds is just horrendous,” Mr Walker said.
“Unfortunately, you’re controlled by the big players, the supermarkets, and they decide what is marketable and what is not.
“You need consumers to really push, push, push.”
Plans to address supply
Queensland University’s Naturally Nutritious program, funded by Hort Innovation, aims to address the lack of orange capsicum supply.
To assist industry, PhD student Rhimjhim Agarwal is researching genetic tools to help select and breed fruit for both higher zeaxanthin production and grower profitability.
“Commercially there is like one or two producers,” Ms Agarwal said.
“These varieties do not have a lot of demand so the varieties haven’t been commercialised that well, so things like temperature resistance and insect resistance, which lowers productivity, impact profitability.”
‘Go outside your comfort zone’
The good news is that the capsicums, if they can be sourced, are great to eat.
“An orange capsicum stores really, really well so their shelf life’s better and their flavour’s very, very nice, very sweet,” Mr Walker said.
“The goodies in it for your health far exceeds some other colours, so I think people, when they go to the shops, just need to go outside their comfort zones.