You may well have heard of probiotics – these are often referred to as “good” or “friendly” bacteria, found in fermented food products like yogurts or supplements, that may beneficially affect our health by improving the balance of our gut bacteria.
Research into probiotics has shown they can help protect against certain gut conditions, including diarrhoea and inflammatory bowel disease. However, more recently scientists have started to consider whether they may be of benefit to brain function, including learning and memory as well as helping in the treatment of depression.
Is there a link between our gut and our brain?
Although the influence of our gut bacteria on brain function may seem odd, researchers have been investigating a biochemical signalling or communication pathway that may explain a link between our gut microbiota, digestive system and brain. The full role in terms of health outcomes is not fully understood, but this pathway is an area of increasing research interest.
And recently an Iranian randomised controlled study, published in the journal Frontiers in Aging Neuroscience, looked at whether probiotic supplements may help improve cognitive function in patients with Alzheimer’s disease.
This 12-week trial recruited 60 patients with Alzheimer’s disease and an average age of 80. They were randomly assigned to two treatment groups; the intervention group received 200ml probiotic milk a day, milk with certain bacteria added to it, and the control group received plain milk.
Cognitive function was measured before and after the 12-week trial using a Mini-Mental State Examination (MMSE), a questionnaire with a maximum score of 30, used to measure cognitive ability including attention, calculation, recall and language.
Study suggests a small improvement in cognition with probiotic supplementation
The researchers reported an improvement in the MMSE score from 8.67 to 10.6 (around +30%) in the group receiving the probiotics, compared with a decrease from 8.47 to 8.00 (around -5%) in the control group.
This is an interesting early study that, in line with some of other emerging research, indicates that our gut microbiota could play a role in cognition, and probiotics may have an effect.
However, it is important to note that the reported changes are small, and it is uncertain whether these are clinically important in terms of function. This was also a short term study and future research is needed to understand whether increasing the time of treatment with probiotics may lead to better outcomes. Even after taking probiotics, everyone remained severely cognitively impaired, and as the subjects all had Alzheimer’s Disease at the start of the study, it’s unclear whether probiotics could help to prevent dementia in the general population.
More research is required before probiotic supplementation is recommended.
So based on the small size and short-term nature of this study, more rigorous research would be required before probiotics could be recommended as an evidence-based treatment for people with Alzheimer’s disease.
There is currently no specific dietary advice for people with Alzheimer’s disease, but why not include some yogurt – it can contribute probiotics to the diet as well as other nutrients such as protein, riboflavin, vitamin B12, iodine and potassium.
Use as a snack, as a pudding or as an accompaniment to savoury dishes like curries.
