Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This chapter reviews the pathogenesis of disordered divalent mineral and bone metabolism in alcoholism, emphasizing the role of impaired vitamin D physiology. Normally, vitamin D metabolites are derived principally from cholecalciferol, which is synthesized in the skin via the energy of sunlight. Most alcoholics have subnormal levels of 25-hydroxyvitamin D [25(OH)D]. Those with Laennec's cirrhosis also have low levels of vitamin D binding protein due to impaired hepatic protein synthesis and as a result, have low serum concentrations of total, but not free, 1,25-dihydroxyvitamin D. The causes of 25(OH)D deficiency in alcoholics include reduced hepatic 25-hydroxylase activity, lack of sun exposure, inadequate dietary intake, and malabsorption. Hypomagnesemia and hypophosphatemia, which are very common in hospitalized alcoholics, result from deficient intake, malabsorption, excessive renal losses, and cellular uptake of both ions. Hypocalcemia in alcoholics is caused primarily by hypoalbuminemia but can result also from deficient intake, malabsorption, hypomagnesemia, and renal calcium wastage. Low vitamin D activity may contribute significantly to the calcium and phosphate deficiencies. Osteoporosis is extremely common in alcoholics whereas osteomalacia is exceptional. However, both bone disorders respond well to vitamin D therapy. Thus, alcoholics should be screened periodically for vitamin D deficiency and osteopenia, and when either is detected they should receive vitamin D supplements.
 ...
PMID:Disorders of divalent ions and vitamin D metabolism in chronic alcoholism. 375 48

A survey of vitamin D status in 152 patients with chronic gastrointestinal conditions and 104 patients with chronic liver diseases is presented. Mild deficiency was common and severe deficiency, as judged by plasma 25-OHD levels less than 8 nmol/l, was encountered in every disease category tested. In the gastrointestinal disease patients, deficiency was significantly more common in patients following gastroenterostomy than other gastric surgery, in patients with active Crohn's disease than in those with inactive disease and in patients with chronic pancreatitis or pancreatic carcinoma with cholestatic features than in those without cholestatic features. Deficiency was as common in patients with Crohn's disease who had not been treated surgically as in those who had. There was no significant correlation between plasma 25-OHD levels and any laboratory index of malabsorption or malnutrition except for serum albumin in the gastric surgery patients, haemoglobin and ESR in the Crohn's disease patients and albumin and vitamin E in the group of patients with gastrointestinal disorders taken as a whole. In the chronic liver disease patients, those with late primary biliary cirrhosis had lower plasma 25-OHD levels than those with histological Stage I and II disease who all had normal levels, and those with pruritus and jaundice were more commonly severely deficient. Whatever the underlying disease process, patients with other coincidental medical conditions were much more likely to be deficient as were patients with cholestasis. Evidence of secondary hyperparathyroidism and osteomalacia on bone histology indicated the clinical relevance of the vitamin D deficiency. This study showed no relationship between abnormal plasma vitamin D binding protein levels and vitamin deficiency.
 ...
PMID:A survey of vitamin D deficiency in gastrointestinal and liver disorders. 654