Chronic disorders of the liver or the gastrointestinal tract (GI) (e.g. malabsorption syndromes, lactose intolerance, Crohn’s disease, colitis ulcerosa, pancreatic insufficiency and primary biliary cirrhosis) frequently cause a combination of osteoporosis and osteomalacia (“osteoporomalacia”) due to deficiencies of vitamins D, K and C. It should be mentioned that patients with Crohn’s disease, even young adults, are subject to sarcopenia frequently related to osteopenia/osteoporosis. The changes which occur in patients with chronic disorders of the GI tract, as listed above, tend to worsen as the patients get older, so that regular screening for osteopenia/osteoporosis is recommended. It is noteworthy that sarcopenia is high even in young patients with Crohn’s disease, and this increases the risk of bone loss. Gastric and intestinal operations (e.g. Billroth I and II and small bowel resections) interfere with absorption and utilisation of calcium and vitamin D and eventually may lead to osteopathy, especially to vertebral osteoporosis. Osteoporosis after gastrectomy and in patients using proton pump inhibitors (PPI) is due to decreased calcium absorption secondary to higher gastrointestinal pH values. Variations in intestinal absorption (with no obvious cause) may lead to hypercalciuria, and this has been linked with calcium nephrolithiasis, bone loss and idiopathic osteoporosis in some patients, including postmenopausal women. These cases are examples of the interwoven connections between gastrointestinal absorption, renal function and skeletal metabolism.