The nutritional supplement, containing extracts from blueberries and green tea combined with vitamin D3 and amino acids - including carnosine - is developed by researchers at the University of South Florida. The researchers tested the supplement, named NT-020, in a clinical trial enrolling 105 healthy adults aged 65 to 85. "After two months, test results showed modest improvements in two measures of cognitive processing speed for those taking NT-020 compared to those taking placebo," said professor Brent Small, school of aging studies, the University of South Florida.