Trials of Souvenaid medical food, which involved 238 people with mild Alzheimer's, found that those who took 125 ml of the drink each day for 48 weeks had significant improvement in their memory.
But the Alzheimer's Society has cautioned that exercise is a more effective way to reduce cognitive decline of the disease.
The Research was published at the Alzheimer's Association International Conference, AAP reported.
"People shouldn't get excited that an off-the-shelf drink is going to transform the lives of people with dementia," Alzheimer's Society director of research Professor Clive Ballard told the Australian news agency.
"While this study showed some benefits for memory, there's no evidence it has any effect on other symptoms such as activities of daily living," Ballard said.
"People would be much better off putting the money they would spend on this drink towards gym membership or a few games of tennis," added Ballard.
"Regular exercise is a far more effective way of reducing cognitive decline. One in three people over 65 will develop dementia. It's vital we continue to fund research into new treatments." Ballard said.