wie lang ist der darm — which blood markers matter?

The human intestine is about 5–7 meters long in adults (small intestine ~3–5 m, large intestine ~1.5 m). Regarding blood markers that matter for gut health, clinically relevant ones include fecal calprotectin (stool, not blood) for inflammatory bowel disease, anti-tissue transglutaminase IgA for celiac disease, and blood markers like CRP and ferritin for general inflammation and iron status. Some DNA tests offer SNP-based risk scores, e.g., rs2395182 in HLA-DQA1 for celiac disease (European minor allele frequency ~22% G). However, evidence for single SNPs is weak (gwas) and not diagnostic. Blood markers like anti-tTG or calprotectin have stronger clinical utility but require medical context. Intestinal length is not assessed via blood markers. Caution: consumer DNA tests often overstate the predictive power of single variants. Always consult a physician for interpretation.