Synopsis: Effect of probiotic supplementation on cognitive function and metabolic status in Alzheimer's disease: a randomized, double-blind, and controlled trial.
In a new study published 10 November 2016, researchers have found that consuming a probiotic drink improved the memory and thinking skills of people with Alzheimer's disease. The study is published in Frontiers in Aging Neuroscience.
Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system. The term probiotic is currently used to name ingested microorganisms associated with beneficial effects to humans and other animals. Studies on the medical benefits of probiotics have yet to reveal a cause-effect relationship, and their medical effectiveness has yet to be conclusively proven for most of the studies conducted thus far. The World Health Organization's (WHO) defines probiotics as "live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host."
Probiotic drinks contain so-called 'good bacteria' that are thought to help the bacteria that live in the gut to support digestive processes. The understanding of how changes in the gut can affect the brain is improving, and in this clinical trial the researchers set out to see whether a probiotic drink could improve memory and thinking in people with Alzheimer's disease.
In the trial, 52 people with Alzheimer's disease were split into two groups, one receiving milk and the other receiving milk with added Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum and Lactobacillus fermentum - bacteria commonly found in probiotic drinks. The study participants received the drink daily over the course of 12 weeks, and undertook tests of memory and thinking, as well as blood tests for metabolic factors at the start and end of the study period.
At the end of the 12 weeks, the participants who received the milk with added bacteria were found to have an improved score on the memory and thinking tests, compared with the group that received normal milk.
The researchers also found reductions in some metabolic factors in the blood, but not others associated with inflammation.
Dr Rosa Sancho, Head of Research at Alzheimer's Research UK, said:
"The brain is often viewed as being separate from the rest of the body but scientists are understanding more about how changes in the body can impact upon the brain too. This new study raises interesting questions about the link between the gut and the brain, and their association with Alzheimer's disease. The improvements in memory and thinking seen in people with Alzheimer's disease in this study will need to be repeated in much larger studies before we can understand the real benefits of probiotics for the brain. We don't fully understand how changes in the gut could be affecting the brain, and Alzheimer's Research UK is funding research in this area to improve our understanding of this link."