ascorbic-acid and Malabsorption-Syndromes

The main theme of this chapter concerns the precise biochemical mechanisms involved in stages up to, and including, gastrointestinal absorption of vitamins and certain selected minerals. Essential data regarding sequential events, immediately following absorption of these micronutrients, are also included. There is reference to water-soluble vitamins that are, in general, either coenzymes in various metabolic reactions or carriers of certain biochemical groupings. In contrast, fat-soluble vitamins frequently function as integral components of cell membranes; they, too, receive ample attention. It is appropriate, nevertheless, to recognize that some minerals required in very small amounts are closely allied biochemically with particular vitamins; these specific associations are apportioned emphasis at relevant places in the text. Although predominant discussion centres on the physiological state, clinical reference is necessarily made to gastrointestinal disorders in which imbalance of vitamins and minerals consequently results in an additional detrimental impact on health.

Topics: Ascorbic Acid; Calcium, Dietary; Chromium Compounds; Drug Interactions; Humans; Intestinal Absorption; Iron Compounds; Malabsorption Syndromes; Micronutrients; Selenium Compounds; Trace Elements; Vitamin A; Vitamin B Complex; Vitamin D; Vitamin E; Vitamin K; Vitamins; Zinc Compounds

This monograph on the clinical chemistry of vitamin B12 reviews the literature on daily requirements, methods for measurement, the effects of drugs on vitamin B12 metabolism absorption, pregnancy, clinical conditions associated with vitamin B12 deficiency, errors of metabolism, and reactions to vitamin therapy. Although only very small quantities of vitamin B12 are required to satisfy the daily requirement, a sufficient supply is stored in the liver to meet normal requirements for at least a 3-year period. A number of drugs are known to affect the absorption of vitamin B12, including neomycin, potassium chloride, p-aminosalicylic acid, and colchicine. Significantly reduced serum concentrations of vitamin B12 have been noted in users of oral contraceptives (OCs), although concentrations still remain within the limits of normal. It appears that the vitamin B12 level in OC users reestablishes itself at a different and somewhat lower level. Vitamin B12 binding protein appears to remain unchanged. A vitamin B12 deficiency is unusual in pregnant women who consume a normal, varied diet. On the other hand, lactating women whose diets are low in animal protein and dairy products may have problems providing enough vitamin B12 to meet their own and their infant's needs; supplementary oral vitamins should be considered.

Topics: Absorption; Adult; Alcoholism; Anemia, Pernicious; Ascorbic Acid; Autoantibodies; Biguanides; Biological Transport; Chemical Phenomena; Chemistry; Chlorpromazine; Contraceptives, Oral; Diet; Female; Gastrectomy; Gastritis; Humans; Intrinsic Factor; Malabsorption Syndromes; Male; Metabolism, Inborn Errors; Middle Aged; Neoplasms; Nervous System Diseases; Nitrous Oxide; Nutritional Requirements; Pancreatic Diseases; Parasitic Diseases; Pregnancy; Pregnancy Complications; Transcobalamins; Vitamin B 12; Vitamin B 12 Deficiency

Topics: Ascorbic Acid; Celiac Disease; Citrates; Colitis, Ulcerative; Crohn Disease; Dietary Fats; Gastrointestinal Diseases; Humans; Hyperparathyroidism; Ileostomy; Intestine, Small; Liver Diseases; Malabsorption Syndromes; Oxalates; Solubility; Urinary Calculi

Topics: Animals; Ascorbic Acid; Biological Transport; Biotin; Diet; Folic Acid; Gastrectomy; Humans; Ileum; Intestinal Absorption; Intestine, Small; Intrinsic Factor; Malabsorption Syndromes; Niacinamide; Nicotinic Acids; Pantothenic Acid; Pyridoxine; Riboflavin; Species Specificity; Stomach; Thiamine; Vitamin B 12; Vitamins

Topics: Ascorbic Acid; Child; Child Nutritional Physiological Phenomena; Child, Preschool; Developing Countries; Diet; Female; Gastrointestinal Diseases; Humans; Hygiene; Infant; Infant Nutritional Physiological Phenomena; Infant, Newborn; Infections; Intestinal Diseases, Parasitic; Iron; Malabsorption Syndromes; Male; Nitrogen; Nutrition Disorders; Nutritional Requirements; Vitamin B 12

Topics: Adult; Anemia, Hypochromic; Ascorbic Acid; Clinical Trials as Topic; Delayed-Action Preparations; Female; Hemoglobinometry; Humans; Iron; Malabsorption Syndromes; Male; Pregnancy

Topics: Ascorbic Acid; Child; Diet; Food Hypersensitivity; Fructose; Fruit; Humans; Malabsorption Syndromes; Male; Scurvy

To investigate whether reduced circulating levels of ascorbic acid in patients with systemic sclerosis (SSc) are a result of malabsorption.. Eight patients with SSc, but with no evidence of bacterial overgrowth, and 8 healthy controls were recruited. On the first day of study, each subject was given orally an aliquot of [14C] ascorbic acid, which was then "flushed out" by oral intake of unlabeled ascorbic acid for the following 7 days. Plasma samples were collected at specified intervals and urine was collected continuously over the 8 day study period. [14C] content of plasma and urine were measured by scintillation counting. For each subject, a plasma [14C] decay curve was drawn. Each subject's ascorbic acid absorption was assessed using the area under the curve (AUC) and the apparent renal clearance (CLr[app]). Ascorbic acid intake was assessed using dietary history and food composition tables.. There were no differences in the dietary intake of vitamin C (p = 0.16) and body mass indices (p = 0.91) between patients and controls. The plasma [14C] AUC and CLr(app) were similar between patients and controls [AUC patient mean (standard deviation, SD) = 37.1 (6.8), AUC control mean (SD) = 38.6 (9.9), p = 0.74; CLr(app) patient mean (SD) = 0.57 (0.24), CLr(app) control mean (SD) = 0.47 (0.27), p = 0.45].. There was no evidence of impaired absorption of ascorbic acid in patients with SSc without bacterial overgrowth compared to healthy controls.

Topics: Absorption; Adult; Ascorbic Acid; Body Mass Index; Carbon Radioisotopes; Female; Gastrointestinal Motility; Humans; Intestines; Malabsorption Syndromes; Male; Middle Aged; Scleroderma, Systemic

Dietary modifications can partly compensate for the alterations in copper homeostasis caused by distal intestinal resection, by improving biliary function. We studied the effects of resecting 50% of the distal small intestine (DSI) on copper status in rats fed three semisynthetic diets (basal diet, and basal diet with cholecalciferol or ascorbic acid). Intestinal resection significantly decreased the digestive (apparent digestibility coefficient; ADC) and metabolic utilization (balance) of copper 1 month after surgery. However, the supplementation of the basal diet with cholecalciferol attenuated the negative impact of surgery, leading to small differences in Cu ADC and Cu balance between transected and resected rats. Ascorbic acid also enhanced copper retention. Copper status was not as markedly affected by intestinal resection as digestive utilization 1 month after the operation. The beneficial effects of cholecalciferol and ascorbic acid at the digestive and metabolic levels suggest ways to lessen the impact of intestinal resection, and to avoid possible long-term postabsorptive alterations in copper distribution.

Topics: Animals; Ascorbic Acid; Cholecalciferol; Copper; Diet; Feces; Intestine, Small; Malabsorption Syndromes; Male; Rats; Rats, Wistar; Tissue Distribution

An investigation of variables important to calcium stone formation in urine indicated significantly increased daily excretion of calcium and oxalate and decreased excretion of ascorbate and citrate by recurrent calcium stone formers. In addition, urine volume, sodium, mucopolysaccharide, and protein were also significantly increased. We compared the uptake of citrate and ascorbate from the gut into the blood in normal controls and stone formers. These studies indicated significantly depressed absorption of both these hydroxycarboxylic acids in recurrent calcium stone formers. We also found that concurrent administration of citrate inhibited ascorbate absorption and increased urinary oxalate excretion after an ascorbate load in normal subjects and stone formers. These findings suggest a mechanism that explains hyperoxaluria in stone patients on the basis of a malabsorption of citrate, ascorbate, and possibly other hydroxycarboxylic acids.

Topics: Absorption; Adult; Ascorbic Acid; Calcium; Citrates; Citric Acid; Female; Humans; Kidney Calculi; Malabsorption Syndromes; Male; Middle Aged; Oxalates; Oxalic Acid; Sodium; Urine

Topics: Adolescent; Ascorbic Acid; Australia; Body Height; Body Weight; Child; Child Nutritional Physiological Phenomena; Child, Preschool; Cholesterol; Deficiency Diseases; Female; Folic Acid; Growth; Humans; Infant; Infant Nutrition Disorders; Intestinal Diseases, Parasitic; Iron; Malabsorption Syndromes; Male; Native Hawaiian or Other Pacific Islander; Nutrition Surveys; Protein Deficiency; Respiratory Tract Infections; Serum Albumin; Vitamins

Topics: Adult; Ascorbic Acid; Blood Cell Count; Blood Glucose; Blood Pressure; Body Weight; Diet Therapy; Feces; Female; Folic Acid; Gastric Acidity Determination; Humans; Ileum; Interpersonal Relations; Iron; Jejunum; Liver Function Tests; Malabsorption Syndromes; Methods; Middle Aged; Obesity; Postoperative Complications; Psychology; Water-Electrolyte Balance

Topics: Adolescent; Ascorbic Acid; Child; Child, Preschool; Humans; Injections, Intramuscular; Malabsorption Syndromes; Thalassemia; Time Factors

Topics: Ascorbic Acid; Blood Glucose; Blood Proteins; Bone Diseases; Celiac Disease; Cholesterol; Esophageal Diseases; Fats; Feces; Female; Gastrectomy; Gastrointestinal Motility; Glucose Tolerance Test; Hemostasis; Humans; Intestinal Absorption; Iodine; Jejunum; Malabsorption Syndromes; Male; Nitrogen; Radiography; Vitamin A Deficiency; Vitamin K; Water-Electrolyte Balance; Xylose

Topics: Adult; Aged; Ascorbic Acid; Ascorbic Acid Deficiency; Female; Humans; Leukocytes; Malabsorption Syndromes; Male; Middle Aged; Postgastrectomy Syndromes

Topics: Ascorbic Acid; Celiac Disease; Gastrectomy; Humans; Injections, Intravenous; Intestinal Absorption; Intestine, Small; Intestines; Malabsorption Syndromes; Metabolism; Pancreas; Portacaval Shunt, Surgical; Sprue, Tropical; Surgical Procedures, Operative; Urine

Topics: Ascorbic Acid; Humans; Intestinal Absorption; Malabsorption Syndromes