"For the first time scientists have shown that probiotics  beneficial live bacteria and yeasts taken as dietary supplements  can improve cognitive function in humans. In a new clinical trial scientists show that a daily dose of probiotic Lactobacillus and Bifidobacterium bacteria taken over a period of just  weeks is enough to yield a moderate but significant improvement in the score of elderly Alzheimers patients on the MiniMental State Examination MMSE scale a standard measure of cognitive impairment. Probiotics are known to give partial protection against certain infectious diarrheas irritable bowel syndrome inflammatory bowel disease eczema allergies colds tooth decay and periodontal disease. But scientists have long hypothesized that probiotics might also boost cognition as there is continuous twoway communication between the intestinal microflora the gastrointestinal tract and the brain through the nervous system the immune system and hormones along the socalled microbiotagutbrain axis. In mice probiotics have indeed been shown to improve learning and memory and reduce anxiety and depression and OCDlike symptoms. But prior to the present study there was very limited evidence of any cognitive benefits in humans.  Here the researchers from Kashan University of Medical Sciences Kashan and Islamic Azad University Tehran Iran present results from a randomized doubleblind controlled clinical trial on a total of  women and men with Alzheimers between  and  years of age. Half of the patients daily received  ml milk enriched with four probiotic bacteria Lactobacillus acidophilus L. casei L. fermentum and Bifidobacterium bifidum approximately  billion bacteria per species while the other half received untreated milk.  At the beginning and the end of the week experimental period the scientists took blood samples for biochemical analyses and tested the cognitive function of the subjects with the MMSE questionnaire which includes tasks like giving the current date counting backwards from  by sevens naming objects repeating a phrase and copying a picture.  Over the course of the study the average score on the MMSE questionnaire significantly increased from . to . out of a maximum of  in the group receiving probiotics but not in the control group from . to .. Even though this increase is moderate and all patients remained severely cognitively impaired these results are important because they are the first to show that probiotics can improve human cognition. Future research on more patients and over longer timescales is necessary to test if the beneficial effects of probiotics become stronger after longer treatment. In a previous study we showed that probiotic treatment improves the impaired spatial learning and memory in diabetic rats but this is the first time that probiotic supplementation has been shown to benefit cognition in cognitively impaired humans says Professor Mahmoud Salami from Kashan University the senior author of the study.  Treatment with probiotics also resulted in lower levels of triglycerides Very Low Density Lipoprotein VLDL highsensitivity CReactive Protein hsCRP in the blood of the Alzheimer patients and likewise a reduction in two common measures called Homeostatic Model Assessment HOMAIR and HOMAB of insulin resistance and the activity of the insulinproducing cells in the pancreas.  These findings indicate that change in the metabolic adjustments might be a mechanism by which probiotics affect Alzheimers and possibly other neurological disorders says Salami. We plan to look at these mechanisms in greater detail in our next study. Walter Lukiw Professor of Neurology Neuroscience and Ophthalmology and Bollinger Professor of Alzheimers disease at Louisiana State University who reviewed the study but was not involved in the research said This early study is interesting and important because it provides evidence for gastrointestinal GI tract microbiome components playing a role in neurological function and indicates that probiotics can in principle improve human cognition. This is in line with some of our recent studies which indicate that the GI tract microbiome in Alzheimers is significantly altered in composition when compared to agematched controls and that both the GI tract and bloodbrain barriersbecome significantly more leaky with aging thus allowing GI tract microbial exudates e.g. amyloids lipopolysaccharides endotoxins and small noncoding RNAs to access Central Nervous System compartments.  The study is published in the openaccess journal Frontiers in Aging Neuroscience."