A Victoria University clinical trial led by Professor Michael Mathai of the Institute for Health and Sport and published in the Journal of Functional Foods in March, found Queen Garnet nectar reduced blood pressure, fasting glucose, insulin and LDL (bad) cholesterol levels in overweight and obese patients who consumed it over three months. Metabolic syndrome is a group of conditions which increase the risk of heart disease, stroke and type 2 diabetes.

The nectar is among a range of value-added products including powders and chewables produced from the Queen Garnet. The specialty fresh line is in season only in February and March. Nutrafruit Limited holds the global licence to market the plum and associated products.

Nutrafruit chief executive officer Luke Couch said the results were significant for the Queen Garnet which had continued to gather evidence of health benefits since it was first harvested in 2014.

The Victoria University study found blood pressure reduction from the nectar was similar to reductions achieved when people took antihypertensive drugs.

"According to the Heart Foundation, there are more deaths caused by high blood pressure in Australia than any other single risk factor. We're excited for the health of Australians, who can gain a range of health benefits, including a lowering of blood pressure, by consuming some nectar daily," Mr Couch said.

"There are very few products that have the research to support being a 'functional food' but Queen Garnet can pin its hat on that.

"As more Australians are trying to find natural foods to enhance their health and wellbeing, taking the nectar is a conversation people at risk of cardiovascular and metabolic diseases could have with their health-care practitioners," he said.

Professor Mathai collaborated with Victoria University PhD student Maharshi Bhaswant and Professor Lindsay Brown of the University of Southern Queensland's (USQ) School of Health and Wellbeing to conduct the study in 2015 and author the report.

The human trial was inspired by similar findings from a USQ study, led by Professor Brown, on obese and hypertensive rats which found the nectar reversed inflammation of the heart and liver, as well as blood pressure and fat levels, Dr Mathai said.

The researchers attribute the effects to the known benefits of the Queen Garnet's anthocyanins - powerful antioxidants found in red, blue and purple fruits and vegetables. Queen Garnet plums contain up to seven times more than other plums.

"Our study showed consumption of Queen Garnet nectar has important and exciting implications for an increasingly sedentary society, Professor Mathai said.

"The reductions in blood pressure, LDL cholesterol and glucose are all beneficial for cardiovascular and metabolic health. In this trial, we slightly improved the patients' chances of becoming diabetic which is great, considering we were giving them a fruit drink which contains natural sugars.

"The results showed a gradual and sustained reduction in blood pressure within six weeks of consuming the nectar and it continued to lower over the trial period by about 10mmHg, which is highly significant for cardiovascular health," Professor Mathai said.

In the trial, patients aged between 20 and 60 were given 250ml/day of Queen Garnet nectar.

"The nectar is a convenient way of administering the dose because, in humans, compliance is always an issue. Ideally, we'd like to see what could happen when taken over 12 months but it's unrealistic to expect volunteers to remain in a trial for that length of time," Professor Mathai said.

He is applying for funding to conduct further research into the plum's benefits, particularly into the effects on obesity and diabetes.

Nectar a viable way to lower blood pressure

Professor Brown, who has led multiple studies into the benefits of the Queen Garnet since it came to his attention in 2015, said the results were a breakthrough for the treatment of cardiovascular and metabolic disease effects.

"Showing that realistic amounts of food can have the same effect as standard drug medication, in this case, in hypertension, is very important," Professor Brown said.

"This is a viable method to treat mild hypertension to prevent it getting worse," he said.

His work, including a study last year which found the nectar significantly reduced the effects of Inflammatory Bowel Disease in rats, has inspired other researchers around Australia to study the plum's special properties.

The trial is among multiple studies conducted on Queen Garnet plums. All have been independently funded by universities.

Research continues into plum's benefits

According to the Australian Bureau of Statistics Australian Health Survey 2014-2015, almost six million Australians aged 18 and over have high blood pressure which can increase the risk of heart disease, stroke, and death.

The latest study is the second which has now found Queen Garnet nectar can reduce blood pressure in both young and old. The first was conducted at the University of Wollongong in 2017.

Further studies are underway at USQ, Queensland Alliance for Agriculture and Food Innovation and the University of Wollongong with the first results of these expected in 2020.