Power of purple: Can pigment in food reduce weight, lower blood pressure?
People age 65 and older asked to take part in study by eating purple shortbread cookies
A study at the University of Manitoba is testing whether the purple pigment in certain fruits prevents — or even reverses — disease.
"We think that the purple colour is very healthy for you," said Peter Jones, director of the Richardson Centre for Functional Foods and Nutraceuticals at the U of M.
At the core of the study is the queen garnet plum, quickly gaining a reputation as a superfood for its antioxidant and anti-inflammatory properties.
Antioxidants and anti-inflammatories can help fight diseases such as diabetes and cardiovascular disease, Jones said.
Researchers around the world have already studied the queen garnet's ability to lower blood pressure in older adults. It has also been reported to have obesity-fighting properties.
Scientists attribute those effects to the fruit's anthocyanins — a chemical found in the red, blue and purple pigmentation of fruits and some vegetables.
Other foods rich in anthocyanins include blueberries, raspberries, black rice, black soybeans, sea buckthorn, purple corn and purple carrots, but the queen garnet contains three to six times the antioxidant content of blueberries and at least five times the level of other plum varieties, researchers say.
In a trial run by the University of Southern Queensland (USQ), researchers added drops of Queen Garnet plum juice to the drinking water of obese rats. After about eight weeks, the rats had returned to their normal body weight and their blood pressure had been reduced, even though they continued eating a high-calorie diet.
"Now we really want to see if that works in the real McCoy, in humans," said Jones, whose department is working with the USQ for the upcoming clinical trials on people.
Rather than a few drops in their drinking water, though, the people taking part in the trials — age 65 and older — will eat purple shortbread cookies.
They contain extract from the Garnet Plum as well as an Australian coconut that has certain fats believed to enhance metabolism and thereby help shed body weight.
"The power of purple is what we're calling it [the cookie]," Jones said.
The five-month trial will include two months of eating one special cookie per day and two months of cookies without the active ingredients, with a month of no cookies in between.
The tests will be randomized, though, so participants don't know which type of cookie they get first. The regular one will have a colouring agent added to disguise it.
The fist-sized Queen Garnet was accidentally created by plant breeders trying to make a disease-resistant version of the common Japanese plum for the Queensland government around 2008.
Nutrafruit, a private company made up of a consortium of Queensland agribusiness people, bought the exclusive licence to market and produce the plum in 2010.
The study of the anthocyanins began a few years ago after the USQ got a chance call from a bankrupt company that had been growing purple carrots and had 50,000 litres of carrot juice it couldn't use.
When they applied it to the rats' water, the results suggested the juice reduced indicators of metabolic disease, which leads to Type 2 diabetes and heart disease.
"So we moved from that to the garnet plum," said Jones.
"The plum is now commercialized in Australia and if the results work well, hopefully, the same would occur here and this could become a source of health if we can prove that it actually has these benefits for people."