PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ASCORBIC ACID DEFICIENCY”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,207 records · Page 67Linked to original sources
PubMed1980

Vitamin C status, serum cholesterol levels and bile composition in the pregnant guinea-pig.

1. Pregnant guinea-pigs receiving a low dose of L-ascorbic acid (0.2 mg/100 g body-weight per d) developed a hypercholesterolaemia in the third trimester of pregnancy, whereas no change in serum cholesterol levels was observed in pregnant animals receiving a higher dose of the vitamin (2 mg/100 g body-weight per d). 2. Pregnancy in the group of guinea-pigs receiving the higher dose of L-ascorbic acid was associated with an increased biliary secretion of bile acids. No change was observed in the biliary secretion of bile acids in pregnant animals receiving the lower dose of L-ascorbic acid, but these animals secreted significantly more cholesterol. 3. Changes in the biliary secretion of cholesterol and bile acids in the pregnant guinea-pig according to L-ascorbic acid intake were reflected in the composition of the gall-bladder bile. Thus, the gall-bladder bile of guinea-pigs receiving the lower dose of L-ascorbic acid contained more cholesterol, while the gall-bladder bile of those animals receiving the higher dose of the vitamin had a higher content of bile acids. 4. The increased cholesterol content of the gall-bladder of pregnant guinea-pigs receiving the lower dose of L-ascorbic acid resulted in decreased bile acid:cholesterol and phospholipid:cholesterol values, conditions predisposing to cholelithiasis.

Animals↗
PubMed1980

Dietary ascorbic acid and muscle carnitine (beta-OH-gamma-(trimethylamino) butyric acid) in guinea-pigs.

Tissue ascorbic acid (AA) contents of approximately 12 and 100% saturation respectively were produced in two groups of guinea-pigs. The 'low-AA' group had a significantly lower muscle carnitine concentrations than the 'high-AA' group. There was no concomitant emergence of the symptoms customarily regarded as characteristic of hypovitaminosis C. It is concluded that muscle carnitine (beta-OH-gamma-(trimethyl-amino)butyric acid) is a highly-sensitive indicator of tissue AA contents; this could account for the lassitude and fatique reported to precede the emergence of frank scurvy in man.

Animals↗
PubMed2005

Vitamin C status and collagen cross-link ratios in Gambian children.

Vitamin C (ascorbate) is essential for hydroxylation of prolyl and lysyl residues in nascent collagen, the failure of which leads to connective tissue lesions of scurvy. Of the pyridinium-type cross-links in mature collagen, pyridinoline requires more hydroxylysyl residues than does deoxypyridinoline. Our study tested the hypothesis that pyridinoline:deoxypyridinoline ratios in urinary degradation products may vary with ascorbate status in man. These ratios were compared between British and Gambian prepubertal boys, mean age 8.3 years, and in Gambian boys between two seasons with contrasting ascorbate availability. The mean cross-links ratio in 216 British boys was 4.36 (SD 0.71), significantly greater (P<0.0001) than in sixty-two Gambian boys: 3.83 (SD 0.52). In the Gambians the cross-links ratio was significantly higher in the dry season (with high ascorbate intake and status) than in the rains (with low intake and status). A 7-week controlled intervention was carried out in Gambian boys during the rainy season (the 'hungry' season, when vitamin C-containing foods are virtually unavailable): 100 mg ascorbate/d was given to one group of thirty-two Gambian boys and placebo to another group. The intervention did not, however, significantly alter the cross-link ratio, possibly because the response time and/or intervention-response delay is >7 weeks. If confirmed, the putative association between ascorbate and collagen cross-link ratios in man could become the basis for a functional test for adequacy of ascorbate status.

Amino Acids↗
PubMed1998

Low levels of serum ascorbic acid in elderly patients with hip fracture.

The serum concentration of ascorbic acid was measured in 40 elderly patients with a recent hip fracture and compared to values measured in 102 home-living elderly. The concentrations were 37 +/- 22 mumol l-1 vs 50 +/- 29 mumol l-1 (p < 0.01). Among the patients admitted from home-living conditions and controls, 20 pairs could be matched with respect to age, sex and season for the test. Serum ascorbic acid concentration was significantly lower in the hip fracture patients (34 +/- 19 mumol l-1 vs 54 +/- 30 mumol l-1, p < 0.01). In the matched pairs, a seasonal variation in serum ascorbic acid concentration was found in the controls, but not in the hip fracture patients. As previous studies have found decreased concentrations of several nutritional factors in hip fracture patients, our findings might indicate that a reduced serum concentration of ascorbic acid could be a part of a general nutritional insufficiency in several patients with hip fracture.

Aged↗
PubMed1996

Vitamin C depletion is associated with alterations in blood histamine and plasma free carnitine in adults.

OBJECTIVE: The purpose of this study was to determine whether carnitine metabolism or histamine degradation would be useful parameters for investigating the optimal requirement for vitamin C. METHODS: Twenty-two non-scorbutic subjects with subnormal vitamin C status (plasma vitamin C < 28 mumol/L) were placed on a metabolic diet low in vitamin C for 3 weeks and repleted with graded doses of vitamin C: 10, 30 and 60 mg vitamin C daily (group 1) or 10,125 and 250 mg vitamin C daily (group 2) for weeks 1, 2 and 3, respectively. Fasting blood samples were collected weekly and analyzed for plasma vitamin C, plasma free carnitine and blood histamine. RESULTS: Group 1 subjects remained in a subnormal vitamin C state throughout the 3-week study, and blood histamine and plasma free carnitine were not impacted by the experimental treatment. Plasma vitamin C in group 2 subjects rose significantly during the study, and these subjects finished the study with an ample vitamin C status indicative of vitamin C intakes above the recommended dietary allowance. Both blood histamine and plasma free carnitine were inversely related to vitamin C status in group 2 subjects. CONCLUSIONS: These data indicate that blood histamine and plasma free carnitine are altered in individuals with subnormal, non-scorbutic vitamin C status and provide evidence that metabolic changes independent of collagen metabolism occur prior to the manifestation of scurvy. Thus utilizing scurvy as an end-point to determine vitamin C requirements may not provide adequate vitamin C to promote optimal health and well-being.

Adult↗
PubMed1999

Body weight and prior depletion affect plasma ascorbate levels attained on identical vitamin C intake: a controlled-diet study.

PURPOSE: To evaluate the role of factors that may affect the level of plasma ascorbic acid (AA), including age, body weight, physical activity, minor illness and the impact of prior depletion and repletion. METHODS: After one month of stabilization on 60 mg vitamin C/day, subjects underwent two complete depletion-repletion cycles (one cycle=one month of vitamin C depletion with nine mg/day, followed by one month of repletion with 117 mg per day). Subjects (68 men, ages 30 to 59 years) did not smoke or drink alcohol during the study. All food was provided by the study. RESULTS: There was extreme individual variability in the plasma AA level achieved on an identical repletion dose: after four weeks at 117 mg/day of vitamin C, AA ranged from 26.8 micromol/L to 85.8 micromol/L. Body weight was inversely associated with plasma AA attained (p<0.0001). Regression analysis indicated that, compared to a 130-lb man, a 200-lb man reached 10 micromol/L lower AA after the first repletion and 18 micromol/L lower AA after the second repletion. One-third of the subjects did not reach a plasma plateau after the first repletion. Prior depletion and apparent repletion also had a major impact, and only 10% of subjects reached the same plasma AA on the second repletion as on the first repletion. CONCLUSIONS: Plasma AA attained on a given dose depends on body weight (or dose per kg of body weight) and on whether or not any prior depletions had been repleted adequately. The results have implications for nutrition recommendations and research design.

Adult↗
PubMed1979

The antioxidant vitamins.

This article is an attempt to study the metabolic functions of vitamin C and E together. Such a study must necessarily be imcomplete owing to the extreme richness of the literature. The increasing importance of the work on free radical reactions, their toxicity and carcinogenic action, and also their relation to the metabolism of metals, particularly iron, copper, selenium, and zinc, shows a number of metabolic pathways with which both vitamins interact. It is hoped that this article will indicate future research possibilities.

Adolescent↗
PubMed2002

Vitamin E prevents increase in oxidative damage to lipids and DNA in liver of ODS rats given total body X-ray irradiation.

We examined the effects of dietary vitamin E (VE) on oxidative damage to DNA and lipids in the liver a few days after total body irradiation (TBI). ODS rats, which lack vitamin C synthesis, were fed either a low VE diet (4.3 mg VE/kg) or a basal VE diet (75.6 mg VE/kg) for 5 weeks while vitamin C was supplied in the drinking water. The VE level in the liver of the low VE group was lower and the levels of lipid peroxides were higher compared to those of the basal VE group: the relative levels in the two groups were 1:30 for VE, 18:1 for 4-hydroxynonenal (HNE), and 10:1 for hexanal (HA). The level of 8-hydroxydeoxyguanosine (8OHdG), a marker of oxidative DNA damage, did not differ between the low VE and the basal VE groups. When the rats received TBI at the dose of 3 Gy and were killed on day 6, the levels of HNE, HA and 8OHdG increased by 2.2-, 2-, and 1.5-times, respectively, in the low VE group, but TBI did not cause such increases in the basal VE group. Changes in antioxidative enzymes (glutathione peroxidase, catalase, and Cu/Zn-SOD) in the liver could not explain the different responses of the two diet groups to TBI-induced oxidative damage. The concentrations of vitamin C and glutathione in the liver did not differ between the two groups. These results suggest that dietary VE can prevent the oxidative damage to DNA and lipids in the liver which appear a few days after TBI at dose of 3 Gy.

8-Hydroxy-2'-Deoxyguanosine↗