Green Tea
Drinking five cups of green tea a day may reduce the risk of prostate cancer by 48 per cent, reports a new study from Japan.
Writing in the American Journal of Epidemiology, researchers from Japan's National Cancer Center report that the benefits of the beverage may be limited to advanced prostate cancer, with no effects observed on localised cancer.
The news adds to a growing list of benefits that has linked tea and tea extracts, ranging from a lower risk of certain cancers to weight loss, and protection against Alzheimer's, have been linked to the polyphenol content of the tea.
Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. Oolong tea is semi-fermented tea and is somewhere between green and black tea.
Guarana
Extracts from the exotic fruit guarana showed excellent antioxidant and antibacterial properties, which could see the exotic berry making a move into cosmetics, new research suggests.
"Due to their high antioxidant, antibacterial and antifungal activities the guarana seed extracts have promising potential as natural antioxidants in the food industries, in the preservation of foodstuffs against a range of food-related bacterial and fungal species or in the pharmaceutical and cosmetic industries," wrote lead author Lucija Majhenic in the journal Food Chemistry.
Interest is growing in plant-derived food additives as replacements to synthetic antioxidants like butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT) to slow down the oxidative deterioration of food.
Indeed, according to a 2003 report by Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts (particularly rosemary), tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by easier consumer acceptance and legal requirements for market access.
Ginseng
An extract from American ginseng berry may reduce blood sugar levels by 30 per cent and aid weight loss, reports a new study from the University of Chicago using obese diabetic mice.
If the results are repeated in further studies and are extrapolated to humans, it could mark the arrival of ginseng juice on the dietary supplements market offering potential benefits for the management of diabetes.
"Our data suggest that ginseng berry juice, as a dietary supplement, may have functional efficacy in consumers with diabetes," wrote the authors in the Journal of Food Science.
An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
Arginine
Supplements of the amino acid L-arginine may lower levels of the heart disease marker homocysteine, say researchers for the first time.
L-arginine has previously been found to lower blood pressure and is often included in nutritional supplements recommended for heart patients.
But a small trial on middle-aged men shows that the amino acid may also benefit the heart through its effect on homocysteine, increasingly considered a marker for heart disease risk.
Observational studies have found that, on average, people with high levels of homocysteine in their blood are more likely to have a stroke. This means that L-arginine could have wider implications for heart health than currently believed.
Stevia
Stevia, the natural sweetener causing a whirlwind of interest around the globe, could also be a rich source of antioxidants and may protect against DNA damage and cancer, says a study from India published yesterday.
An extract from Stevia rebaudiana leaves was found to contain an abundance of antioxidant polyphenols, including quercitrin, apigenin, and kaempferol. Subsequent tests showed that the extract could protect against DNA strand scission by hydroxide radicals, states the report in the Journal of Agricultural and Food Chemistry.
"These results indicate that Stevia rebaudiana may be useful as a potential source of natural antioxidants," wrote lead author Srijani Ghanta from the Indian Institute of Chemical Biology in Kolkata.
Derived from the South American plant stevia rebaudiana, stevia is said to have up to 300 times the sweetness of sugar. Its taste has a slower onset and longer duration than that of sugar, and developments in processing methods have already claimed to have solved the problem of the ingredient's liquorice-like aftertaste.
