Plum efficacy is gaining interest as an immune boosting food, thanks to the fact it is the world’s most potent natural source of vitamin C. The Kakadu plum (Terminalia ferdinandiana) is a small, green fruit that packs a powerful punch – it has 100 times more vitamin C than the humble orange. The nutrient-rich Australian native is also thought to help combat inflammatory conditions, such as rheumatoid arthritis and cardiovascular disease.
Plums are also a good source of polyphenols, which include flavonoids (anthocyanin, proanthocyanidin, catechin, quercetin and rutin), as well as tannins and phenolic acids, including chlorogenic, neochlorogenic and coumaric acid. These phytochemicals have been shown to provide a variety of health benefits, including antimicrobial properties and cardiovascular protection.
A study at Edith Cowen University found that Kakadu plums could reduce low-density lipoprotein cholesterol (LDL) and blood glucose levels in postmenopausal women, and this effect was particularly pronounced in those with elevated LDL. The research was published in the journal Nutrition.
The researchers studied data from nine trials with eleven arms involving 592 participants. Six of the trials used dried plum powder and the remainder used fresh, organically grown plum juice. The trials had durations ranging from two to 12 weeks, and randomised control designs were employed. Some trials were parallel, while others used a crossover design. The average age of the participants was 47, and the number of subjects in each treatment group varied from three to eighteen.
Results showed that a high intake of plums reduced total and LDL cholesterol in the treated groups, but not the non-treated group. However, there was considerable heterogeneity between the studies, and a random-effects meta-analysis was conducted. This indicated that the effect of plums on lipid profiles was a result of both the type of plum and the method of administration.
In the male cohort, the ‘HoneySweet’ and ‘Stanley’ plum-treated groups had mild inflammation of the salivary glands and the kidney, but these symptoms were not greater than those seen in the CD-treated group. In addition, the percentage of neutrophils was lower in the ‘HoneySweet’ plum-treated group, but all WBC and hematological parameters were within normal ranges.
The ‘HoneySweet’ ‘Plum Pox Virus-resistant’ plum variety was developed using interfering RNA technology. This approach is able to target and silence specific gene expression, preventing the production of new viral proteins that cause disease. This approach could be useful for developing other crops that are resistant to disease, such as graft-borne diseases or viruses. However, there are many hurdles that need to be overcome before this technology can be widely applied in the field, such as regulatory barriers and concerns about environmental safety. The use of this technology also raises ethical questions about the future use of genetically modified foods.