Many people now consume probiotics in fermented foods like yogurt and in supplements, because scientific research confirms they improve digestion, reduce IBS symptoms and boost immunity.

But probiotics aren’t just for digestion anymore.

As the connection between the gut and the brain becomes better known, more folks are likely to take these friendly bacteria to enhance mood, lower anxiety and help them handle stress.

Since this gut-brain axis is now scientifically established, some researchers wondered if probiotics could help patients with Alzheimer’s.

Probiotics Improve Cognitive Test Scores

Studies have already shown that the gut bacteria in Alzheimer’s patients are different from those in people of the same age who are free of the disease. Animal studies also show that probiotics bring on improvements in learning and memory where these functions were previously impaired.

Now, in a new study, scientists from Kashan University in Iran recruited 52 men and women aged between 60 and 95 diagnosed with Alzheimer’s disease.

Half the patients were given a daily 200 ml (7 fluid ounces) drink of milk containing four types of 400 billion bacteria each: three strains of the lactobacillus genus (acidophilus, casei, and fermentum), as well as Bifidobacterium bifidum.

The other half were given the same amount of milk, but without probiotics. The study was double-blind, so neither patients nor researchers knew what type of milk each participant was drinking.

Blood samples were taken and all were given a cognitive test at the start called the mini-mental state exam (MMSE). This asks simple questions to test language, attention and memory. A maximum score on the MMSE is 30. A score under 12 indicates severe dementia. A person with Alzheimer’s would expect to decline by two to four points each year.

At the end of 12 weeks, the researchers drew blood samples again and repeated the tests.

The results for the group not taking the milk with added bacteria was what the researchers expected. Their scores declined from 8.5 to 8.0. But those drinking milk fortified with probiotics saw their scores increase significantly from 8.7 to 10.6.

Probiotics Improve Important Blood Markers

The lead researcher, Professor Mahmood Salami, said in November 2016, “This is the first time that probiotic supplementation has been shown to benefit cognition in cognitively-impaired humans.”

It’s a remarkably easy way to improve your brain health. I would just caution that confirming studies are needed. Results can vary considerably from one study to another.

Other findings from the study were that probiotics lowered triglycerides (blood fats), very low density lipoprotein cholesterol, high-sensitivity C-Reactive Protein (a marker for inflammation) and two measures of insulin resistance (measuring risk of diabetes).

While these results indicate that probiotics may lower the risk of cardiovascular disease, the same indicators of poor health also play roles in vascular dementia and perhaps in Alzheimer’s disease.

In Professor Salami’s words, these changes “might be a mechanism by which probiotics affect Alzheimer’s and possibly other neurological disorders.”

Walter J. Lukiw, B.S., M.S., Ph.D., Bollinger Professor of Alzheimer’s disease at Louisiana State University, said the study was “interesting and important because it provides evidence for gastrointestinal tract microbiome components playing a role in neurological function, and indicates that probiotics can, in principle, improve human cognition.”


  1. http://journal.frontiersin.org/article/10.3389/fnagi.2016.00256/full