Linda Paulo
Assistant Lecturer/PhD Student; Muhimbili University of Health and Allied Sciences
Linda is a PhD student in Epidemiology at the University Medical Center, Utrecht which collaborates with the Muhimbili University- Cardiac Center of Excellence. Her research focuses on studying the link between gut microbiota, dietary patterns and Metabolic Syndrome in rural and urban residents in Tanzania. She is a Medical Doctor and works as an assistant lecturer at the School of Public Health at Muhimbili University of Health and Allied Sciences in Tanzania. In 2018, she received a Master of Science in Global Health Nutrition from the London School of Hygiene and Tropical Medicine in the United Kingdom.
Abstract
Background: Sub-Saharan Africa(SSA) is among global regions facing rapid transitions including changes in diet and lifestyle to westernized patterns(1). These changes are partly linked to the alteration in the composition and diversity of the gut microbiota and the consequent increase in the prevalence of Non-communicable diseases(2–8). This systematic review analysed published articles from SSA countries that examined the differences in the composition and diversity of gut microbiota along the urbanization gradient.
Main review question: What are the effects of urbanization on gut microbiota in Sub-Saharan African countries?
Specific questions: 1. What are the differences in the gut microbiota of the rural and urban residents within Sub-Saharan African countries? 2. What are the potential explanatory factors that affect the gut microbiota of residents in Sub-Saharan African countries? e.g diet, sanitation, medical care, gut protozoa and helminths
Methods: Relevant peer-reviewed articles that examined the link between the urbanization gradient, dietary patterns and gut microbiota between 2000-2022 using culture-independent techniques were included. A search to locate papers was done in; PubMed/ Medline, Scopus, Web of Science and Embase. Three main search concepts were used: Gut microbiota, Sub-Saharan African countries and urbanization. A total of 3265 studies were identified and screened. Eighty-nine (89) studies underwent full-text review and 23 studies were extracted.
Results: Reporting of the diversity and composition of gut microbiota varied between studies. Therefore, complete mapping of the gut microbiota across the palaeolithic, rural and urban gradient is limited. Out of the included studies, 4 studies done in rural settings and 3 in the palaeolithic settings reported 6 phyla in common. Firmicutes and Bacteroidetes were the most abundant phyla in both settings followed by Proteobacteria which was higher in rural settings. At the level of genera, there were no apparent differences in the relative abundance across the urbanization gradient. Further, intestinal parasites are associated with the composition and diversity of the gut microbiota.
Conclusion: Alpha and beta diversity of the gut microbiota is higher among hunter-gatherers and rural residents compared to urban residents as shown in other studies and meta-analyses of the 16S gene across geographical locations.