From gut to brain: Exploring the role of prebiotics on mental health

Did you know that your gut, often overlooked, plays a crucial role in your overall health? It's not just responsible for digestion; it's a complex ecosystem teeming with billions of microorganisms that influence everything from your mood to your immune system.

Often referred to as our "second brain," our gut harbours a complex ecosystem of microorganisms that play a crucial role in our overall health. 

Among the scientists making strides in this field to uncover deeper connections between gut health, chronic diseases and mental health, is Dr Humphrey Mabwi, a Regional Scholarship and Innovation Fund (Rsif) graduate, whose PhD work revolved around the design of synthetic human gut microbiota ecosystem models for screening novel prebiotics from phytochemicals. 

Dr Mabwi also won the best young researcher award at the just-concluded Kenya National Research Festival 2024.

This model allowed him to study how different types of plant-based substances (phytochemicals) could feed the good bacteria in our gut. By understanding how these substances affect the gut bacteria, the researcher hopes to develop new prebiotic foods that can improve our overall health.

"The gut microbiome, a collection of microorganisms primarily residing in our intestines, is essential for breaking down food, producing vitamins and bolstering our immune system," explains Dr Mabwi. "Through the gut-brain axis, these microorganisms influence our mood, emotions, and behaviour."
 
What exactly are prebiotics and probiotic,s and how do they aid our wellbeing? 

Prebiotics are non-digestible fibres that serve as "food" for the beneficial bacteria (probiotics) in our gut. These fibres, found in a variety of plant-based foods, are not digested by human enzymes, but are fermented by gut bacteria, promoting their growth and activity. Probiotics are live microorganisms, often referred to as "good" bacteria, which, when consumed in adequate amounts, confer health benefits.

The 38-year-old Kenyan, a lecturer at the Department of Nutritional Sciences at Masinde Muliro University of Science and Technology, graduated with a PhD in Molecular and Biotechnology at Sokoine University of Agriculture in Tanzania and did his laboratory research work at the Korea Institute of Science and Technology.

A healthy gut microbiome is linked to a reduced risk of chronic diseases like diabetes, heart disease and certain cancers. "Imbalances in gut bacteria can trigger inflammation, contributing to various health issues," Dr Mabwi adds. "By nourishing our gut with a diet rich in fibre and fermented foods, we can promote the growth of beneficial bacteria and strengthen our immune system."

Prebiotics can be found in a variety of fiber-rich foods, including whole grains, legumes, fruits, vegetables, nuts and seeds, while probiotics are live in fermented foods. 

The lecturer in the areas of Food Microbiology, Food Biotechnology and Food biochemistry research, emphasises the need to revolutionise the way we approach gut health and disease prevention.

Dr Mabwi, who holds a Master of Science in Molecular Biology & Biochemistry from Northeast Normal University, China, is at the forefront of a scientific revolution that's redefining our understanding of mental health. His groundbreaking work explores the intricate relationship between gut health and mental well-being.

"The gut microbiome, a complex ecosystem of microorganisms, plays a pivotal role in our overall health," explains Dr Mabwi. "Imbalances in this ecosystem can disrupt communication between the gut and brain, leading to conditions like depression and anxiety."

Dr Mabwi's research delves into the potential of dietary interventions, particularly the use of prebiotics derived from natural sources, to restore gut health and improve mental well-being. His work is inspired by the wisdom of traditional diets and the power of nature to promote healing.

“By understanding the intricate connection between the gut and the brain, we can unlock new strategies for preventing and treating mental health disorders,” says the researcher. 

Dr Mabwi's research offers a glimmer of hope for a future where mental health is viewed through a holistic lens, encompassing both psychological and physiological factors.

“A healthy gut microbiome maintains the integrity of the intestinal barrier, which prevents harmful pathogens or germs from entering our bloodstream by forming a firm layer inside our intestines. This barrier helps ensure that even if we consume food with germs, they won’t easily reach our bloodstream. If harmful germs cross into the bloodstream, it can have serious health effects. Beneficial gut microbiota, or probiotics, produce metabolites called short-chain fatty acids. These, such as butyric acid, enhance immune responses and reduce inflammation,” he explains.

“In terms of mental health, the gut-brain axis is critical: an imbalance in gut microbiota can disrupt communication between the gut and brain, reducing neurotransmitter production and potentially leading to increased inflammation, which is linked to depression and anxiety,” the researcher says. 

His journey into this field was sparked by a profound realisation: the potential to address mental health challenges through dietary interventions. He notes that this insight has particular relevance in Kenya, where traditional foods might hold keys to better mental health.

"Each Kenyan culture has unique dietary traditions that can positively influence gut microbiota diversity," Dr Mabwi says. He's particularly interested in how traditional fermented foods, common across different Kenyan communities, can serve as natural probiotics, enhancing both gut and mental health. Apart from healthy food, the researcher notes physical health is key to a good gut. 

In a breakthrough moment during his research, Dr Mabwi discovered a promising phytochemical in aloe vera that could improve gut microbiota and boost immunity. This finding exemplifies his innovative approach to bridging traditional remedies with modern science.

His ground-breaking research efforts culminated in the publication of four research articles, showcasing his commitment to advancing knowledge in his field.

Through his PhD research, Dr Mabwi has developed synthetic human gut microbiota models, allowing him to study these complex interactions without human subjects. "I designed an artificial system that mimics the human intestine," he explains, hoping that hospitals and research institutions will adopt this technology to advance gut health research.

The implications of his work extend far beyond the laboratory. Dr Mabwi emphasises the practical steps people can take to improve their mental health through gut-conscious choices. "A diverse diet that includes fruits, vegetables, whole grains, legumes, nuts, and seeds promotes bacterial diversity in our gut," he advises. 

"Less diverse bacteria can lead to poor gut health, which in turn affects our mental wellbeing," he adds. 

Dr Mabwi is particularly concerned about the impact of modern dietary habits on mental health. "We should moderate refined foods because they harm gut health," he warns. Instead, he advocates for a balance between traditional and contemporary diets, highlighting the benefits of foods like fermented porridge made from millet or sorghum, which provide both probiotics and prebiotics.

Dr Mabwi's vision extends to public health policy and awareness. He plans to collaborate with nutritionists, doctors and public health officials to integrate gut health considerations into mental health treatment protocols. "Many people, even within the research community, have limited knowledge of the gut microbiome and its impact on mental health," he observes.

His work comes at a crucial time, as mental health challenges continue to rise globally. Data shows that one in four Kenyans may experience a mental health issue at some point in their lives, with common disorders including depression, anxiety, and substance use disorders. The World Health Organization ranked Kenya as the fifth highest in Africa for cases of depression, estimating that about two million people suffer from this condition alone.

A significant proportion of individuals suffering from mental illnesses do not receive adequate care due to stigma and lack of resources. Estimates suggest that about 42 per cent of patients in general medical facilities exhibit symptoms of severe depression 

"If we don't pay attention to what we eat, it disrupts the gut microbiota balance, leading to what we call dysbiosis," he explains. "This imbalance can contribute to chronic mental health issues."

Through public education initiatives and partnerships with healthcare providers, Dr Mabwi hopes to make his research findings accessible to everyone. He's developing easy-to-understand materials about gut health and its role in mental wellness, planning community workshops, and utilising social media to spread awareness.

"The responsibility falls on all of us –ordinary people, doctors, nutritionists, and policymakers – to promote healthy lifestyles and educate the public," he asserts. His approach represents a paradigm shift in mental health treatment, suggesting that the path to better mental health might start not in the mind, but in the gut.

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