Why do I not produce lactase? Understanding the core reasons
                                
                                
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                                    4 min read                                
                            
                                Globally, approximately 65% of the human population has a reduced ability to digest lactose after infancy, a condition known as lactase non-persistence. The answer to "Why do I not produce lactase?" is most often rooted in your genetics, which is a normal, evolutionary-driven trait for most adults.