Myths vs facts: LCT and Allergie

There is no strong evidence linking the LCT gene (lactase persistence) directly to allergies. LCT variants determine whether an individual can digest lactose (lactase persistence) or not (lactose intolerance). Lactose intolerance is a digestive condition, not an allergy. True milk allergy is an immune reaction to milk proteins (e.g., casein, whey) and is influenced by different genes. People often confuse the two, leading to unnecessary dietary restrictions. A DNA test for LCT can predict lactose intolerance but not allergy risk. Research on LCT and allergic diseases (e.g., asthma, eczema) is mixed and mostly observational, with small effect sizes. Consumer tests like MyBody-X may include LCT markers, but they are not validated for allergy prediction. Caveat: If you suspect a milk allergy, consult an allergist for IgE testing, not a DNA test. Evidence: human-strong for lactose intolerance, unclear for allergies. Myth: LCT causes allergies. Fact: LCT only affects lactose digestion.