Genetic Polymorphism of the Lactase Gene (LCT) and Lactose Intolerance Prevalence in Fulani and Igbo Communities

Lactase persistence, regulated by polymorphisms in the LCT gene promoter region, determines an individual's ability to digest lactose into adulthood. The Fulani pastoralist community has historically maintained high dairy intake, potentially driving positive selection for lactase persistence alleles, while populations with less dairy-based diets such as the Igbo may exhibit higher lactose intolerance rates. This comparative study investigated LCT gene polymorphisms and lactose intolerance prevalence in Fulani communities in Adamawa State (North East) and Igbo communities in Imo State (South East). A total of 120 adult participants were recruited (60 per ethnic group). Genotyping of the C/T-13910 and G/A-22018 polymorphisms was performed using restriction fragment length polymorphism (RFLP)-PCR. A hydrogen breath test was administered to assess lactose malabsorption. Results indicated a significantly higher frequency of the lactase persistence allele (T-13910) among Fulani participants compared to Igbo counterparts, consistent with the pastoralism hypothesis. Breath hydrogen levels correlated significantly with genotype. This study contributes to nutritional genomics research and informs dietary guidance for these ethnically distinct Nigerian populations. Keywords: lactase persistence, LCT gene, lactose intolerance, Fulani, Igbo