Healthy gut, healthy mind
16 April 2023
With the percentage of the population aged 65 and above reaching 7.3 per cent in 2022, Malaysia is officially an ageing society based on the United Nations' definition. The elderly population is expected to expand further to 15 per cent in 2050, making Malaysia an aged nation. The increasing number of elderly will come with higher neuronal dysfunction, neuronal loss, and cognitive decline rates. Consequently, the number of neurodegenerative diseases such as dementia, Alzheimer's disease and Parkinson's Disease is projected to rise in the coming decades.
It is not yet widely known, but cognitive health is very much associated with gut health. It has been discovered that the brain and gut constantly "talk" to each other through a complex network of neurons, hormones and other signalling molecules. Specifically, the microbes in the gut can produce metabolites, such as short-chain fatty acids (SCFAs), that are able to cross the blood-brain barrier and modulate neurotransmitter activity in the brain. Additionally, neurotransmitters such as serotonin, gamma-aminobutyric acid (GABA) and dopamine are produced and regulated by the microbial community in the gut.
"As members of a research group comprising scientists from Malaysia, Canada, and the US, we have discovered compelling evidence of modified gut bacteria and urine metabolites in Parkinson's patients in Malaysia. Our subsequent study revealed a significant correlation between the alterations in certain microbial species and the clinical neurological indicators, further explaining specific gut-brain axis mechanisms leading to changes in cognitive ability," stated Dr Chong Chun Wie from the School of Pharmacy, Monash University Malaysia.
According to Dr Chong, the gut microbial community can also influence cognitive function by regulating the immune system and inflammation. The increase of pro-inflammatory microbes, including Escherichia coli and Helicobacter pylori, may induce immune responses, resulting in chronic inflammation, a condition implicated in many cognitive disorders, such as Alzheimer's Disease and depression.
Since gut health is pivotal to maintaining good cognitive health, keeping a healthy gut is key to reducing the risk of cognitive decline. A "gut-friendly" diet rich in vegetables and fruit encourages the fermentation of fibre, which produces SCFAs such as acetate, butyrate and propionate, which play roles in preventing and reducing gut inflammation. In addition, food containing prebiotic fibre, such as banana (inulin), onion (fructooligosaccharides - FOS), garlic (FOS) and apple (pectin), are energy sources of beneficial bacteria in the gut.
"It is interesting to note that traditional Malaysian foods, for instance, nasi ulam, fruit rojak and chapati, are packed with soluble and insoluble fibre that helps support the growth of beneficial bacteria and assist in bowel movement. Traditional fermented food such as tempeh and tempoyak may also be a good source of probiotics. Further research will help us to understand better the interplay between the Malaysian microbiome, diet and cognitive health. These insights can then be used to design better diets and even specific microbiome modification interventions to improve cognitive health," Dr Chong elaborated.
To better understand the composition of the Malaysian microbiome, Monash University Malaysia is partnering with AMILI, a precision gut microbiome company focused on the Asia microbiome, to conduct the 1000MYMicrobiome project. The project aims to establish the core microbiome of Malaysian across age and ethnic groups.
To participate as a stool donor to advance Malaysian Microbiome Research, visit bit.ly/1000mymicrobiome.