What to watch with LCT and Sport?

The interplay between LCT genetics (lactase persistence vs. non-persistence) and sport is clinically relevant but evidence is mostly mechanistic. Lactase non-persistence leads to lactose intolerance, causing bloating, cramps, and diarrhea after dairy intake. For athletes, this can impair performance, especially when consuming milk-based shakes or dairy pre/post workout. Studies suggest that lactose-intolerant athletes can achieve similar outcomes with lactose-free alternatives or plant-based proteins. Some research indicates that reducing lactose intake decreases GI distress during exercise. However, large RCTs directly linking LCT genotype to athletic performance are lacking. The genetic information should be used as a guide, not a rule. Practical advice: if LCT non-persistent, test low-lactose diet before competitions; if persistent, dairy is fine. Caveat: individual tolerance varies; a food diary is recommended.