Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Wilderness Environ Med ; 31(4): 454-456, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32861618

RESUMO

In European countries, vitamin A toxicity is most often the result of an excessive intake of vitamin supplements and rarely the consequence of the ingestion of a large carnivorous fish liver. We report 3 cases of vitamin A poisoning after fish liver ingestion in mainland and overseas France. The patients were a 12-y-old girl, a 36-y-old pregnant woman, and a 62-y-old man. They experienced headache, nausea, emesis, and desquamation. Laboratory examination showed a high serum retinol level in the girl. The woman's pregnancy progressed to a miscarriage. This case series shows that this kind of poisoning is not restricted to the polar regions. In patients presenting with flushing combined with signs of intracranial hypertension, accurate questioning of the patient's diet is crucial to avoid misdiagnosis and unnecessary examinations. Pregnant women or women of child-bearing age should be informed of the risk to pregnancy in the case of excessive fish liver ingestion.


Assuntos
Peixes , Doenças Transmitidas por Alimentos/etiologia , Hipervitaminose A/etiologia , Fígado , Centros de Controle de Intoxicações , Vitamina A/sangue , Adulto , Animais , Criança , Feminino , França , Humanos , Hipervitaminose A/sangue , Hipervitaminose A/patologia , Masculino , Pessoa de Meia-Idade , Gravidez , Complicações na Gravidez
2.
Am J Clin Nutr ; 110(1): 91-101, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31089689

RESUMO

BACKGROUND: In some regions, multiple vitamin A (VA) interventions occur in the same target groups, which may lead to excessive stores. Retinol isotope dilution (RID) is a more sensitive technique than serum retinol to measure VA status. OBJECTIVE: We evaluated VA status before and after a high-dose supplement in preschool children living in a region in South Africa with habitual liver consumption and exposed to VA supplementation and fortification. METHODS: After baseline blood samples, subjects (46.7 ± 8.4 mo; n = 94) were administered 1.0 µmol [14,15]-13C2-retinyl acetate to estimate total liver retinol reserves by RID with a follow-up 14-d blood sample. Liver intake was assessed with a frequency questionnaire. In line with current practice, a routine 200,000 IU VA capsule was administered after the RID test. RID was repeated 1 mo later. Serum retinyl esters were evaluated using ultra-performance liquid chromatography. RESULTS: At baseline, 63.6% of these children had hypervitaminosis A defined as total liver retinol reserves ≥1.0 µmol/g liver, which increased to 71.6% after supplementation (1.13 ± 0.43 to 1.29 ± 0.46 µmol/g; P < 0.001). Total serum VA as retinyl esters was elevated in 4.8% and 6.1% of children before and after supplementation. The odds of having hypervitaminosis A at baseline were higher in children consuming liver ≥1/mo (ratio 3.70 [95% CI: 1.08, 12.6]) and in children receiving 2 (4.28 [1.03, 17.9]) or 3 (6.45 [0.64, 65.41]) supplements in the past 12 mo. Total body stores decreased after the supplement in children in the highest quartile at baseline compared with children with lower stores, who showed an increase (P = 0.007). CONCLUSIONS: In children, such as this cohort in South Africa, with adequate VA intake through diet, and overlapping VA fortification and supplementation, preschool VA capsule distribution should be re-evaluated. This trial was registered at https://clinicaltrials.gov/ct2/show/NCT02915731 as NCT02915731.


Assuntos
Dieta , Alimentos Fortificados , Hipervitaminose A/sangue , Fígado , Ovinos , Vitamina A/administração & dosagem , Animais , Pré-Escolar , Suplementos Nutricionais , Alimentos Fortificados/análise , Humanos , Fígado/química , África do Sul , Vitamina A/análise , Vitamina A/sangue
3.
Am J Clin Nutr ; 108(5): 997-1005, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30475970

RESUMO

Background: Minimal human data exist on liver vitamin A (VA) compared with serum biomarkers. Cutoffs of 5% and 10% total serum VA as retinyl esters (REs) suggest a VA intoxication diagnosis. Objectives: We compared total liver VA reserves (TLRs) with the percentage of total serum VA as REs to evaluate hypervitaminosis with the use of US adult autopsy samples. Secondary objectives evaluated serum retinol sensitivity, TLRs among lobes, and hepatic α-retinol concentrations, an α-carotene cleavage product. Design: Matched serum and liver samples were procured from cadavers (n = 27; mean ± SD age: 70.7 ± 14.9 y; range: 49-101 y). TLRs and α-REs were quantified by ultra-performance liquid chromatography. Pearson correlations showed liver and serum associations. Sensitivity and specificity were calculated for >5%, 7.5%, and 10% total serum VA as REs to predict TLRs and for serum retinol <0.7 and 1 µmol/L to predict deficiency. Results: Serum RE concentrations were correlated with TLRs (r = 0.497, P < 0.001). Nine subjects (33%) had hypervitaminosis A (≥1.0 µmol VA/g liver), 2 of whom had >7.5% total serum VA as REs; histologic indicators corroborated toxicity at 3 µmol/g liver. No subject had >10% total serum VA as REs. Serum retinol sensitivity to determine deficiency (TLRs <0.1 µmol VA/g) was 83% at 0.7 and 1 µmol/L. Hepatic α-retinol was positively correlated with age (P = 0.047), but removing an outlier nullified significance. Conclusions: This study evaluated serum REs as a biomarker of VA status against TLRs (gold standard), and abnormal histology suggested that 7.5% total serum VA as REs is diagnostic for toxicity at the individual level in adults. The long-term impact of VA supplements and fortificants on VA status is currently unknown. Considering the high prevalence of hypervitaminotic TLRs in this cohort, and given that many countries are adding preformed VA to processed products, population biomarkers diagnosing hypervitaminosis before toxicity are urgently needed. This trial was registered at clinicaltrials.govas NCT03305042.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/metabolismo , Hipervitaminose A/diagnóstico , Fígado/metabolismo , Deficiência de Vitamina A/metabolismo , Vitamina A/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Carotenoides/metabolismo , Estudos de Coortes , Suplementos Nutricionais/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/sangue , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/mortalidade , Ésteres/sangue , Feminino , Alimentos Fortificados/efeitos adversos , Humanos , Hipervitaminose A/sangue , Hipervitaminose A/metabolismo , Hipervitaminose A/mortalidade , Masculino , Pessoa de Meia-Idade , Vitamina A/efeitos adversos , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/tratamento farmacológico
4.
Clin Nutr ESPEN ; 23: 19-24, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29460797

RESUMO

Carotenoids are generally 40-carbon tetraterpenoids responsible for most of the yellow, orange and red colours throughout the natural world. Pro-vitamin A carotenoids serve as the precursors of vitamin A. In addition to that, carotenoids exhibit range of important protective mechanisms in human health. Hypercarotenaemia is characterized by carotenodermia resulting in yellowing of the skin specially palms and soles. Hypercarotenaemia develops in subjects consuming high levels of carotenoid rich foods or ß-carotene supplements (>30 mg day-1) over a period of months. Less or normal intake of carotenoids very rarely gives rise to metabolic carotenaemia due to genetic defects of the enzyme 15-15'-carotenoid dioxygenase. Moreover, it is known that those with hypothyroidism and diabetes mellitus tend to develop hypercarotenaemia with the normal intake of carotenoid rich foods. Further, hypercarotenaemia has been reported in anorexia nervosa. However, recently some studies have been shown that there is no major correlation between carotenoid intake and hypercarotenaemia indicating that a genetic factor is at play in development of hypercarotenaemia. Therefore, the subjects appear to need to be genetically pre-disposed to hypercarotenaemia.


Assuntos
Carotenoides/administração & dosagem , Carotenoides/sangue , Hipervitaminose A/sangue , Frutas , Humanos , Hipervitaminose A/diagnóstico , Hipervitaminose A/genética , Verduras , Vitamina A/administração & dosagem , Vitamina A/sangue
5.
Eur J Clin Nutr ; 69(12): 1346-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26330146

RESUMO

Vitamin A (VA) deficiency is a public health problem in many countries. The World Health Organization recommends high-dose VA supplements to children aged 6-59 months based on unequivocal evidence that supplements decreased mortality risk. VA supplements were meant as a temporary intervention until more sustainable approaches could be implemented. Fortification of processed foods with preformed VA is a means to improve VA status. The most recent addition of retinyl palmitate to cooking oil in countries that may also fortify margarine and milk will undoubtedly have a positive impact on VA status. However, quantitative measures have not been used to assess the underlying VA status of the groups who have adopted widespread fortification. The addition of preformed VA to otherwise adequate diets in VA may cause excessive total body stores. Monitoring population status will require accurate VA assessment to ensure that hypervitaminosis does not prevail. This perspective describes a cohort of rural Zambian children who have adequate diets in VA, mostly as provitamin A carotenoids; who were given high-dose VA supplements till the age of 5 years; who have access to VA-fortified sugar; and whose mothers had access to VA-fortified sugar throughout pregnancy and lactation. Many of these children turned orange during mango season, and this phenomenon occurred at estimated liver reserve concentrations >1 µmol retinol equivalents/g liver. It will be necessary to continue to monitor VA status, including all sectors of the population that have access to successful interventions, to optimize health with the intent to lower retinol content of fortified foods or better target VA supplementation to areas of most need.


Assuntos
Alimentos Fortificados , Hipervitaminose A/epidemiologia , Pele/patologia , beta Caroteno/sangue , Pré-Escolar , Dieta , Suplementos Nutricionais , Diterpenos , Relação Dose-Resposta a Droga , Medicina Baseada em Evidências , Humanos , Hipervitaminose A/sangue , Lactente , Mangifera , Estado Nutricional , Recomendações Nutricionais , Ésteres de Retinil , População Rural , Estações do Ano , Vitamina A/administração & dosagem , Vitamina A/análogos & derivados , Vitamina A/análise , Vitamina A/sangue , Zâmbia/epidemiologia
6.
J Nutr ; 145(5): 847-54, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25809683

RESUMO

Vitamin A plays an essential role in animal biology and has negative effects associated with both hypo- and hypervitaminosis A. Many notable interventions are being done globally to eliminate vitamin A deficiency, including supplementation, fortification, and biofortification. At the same time, it is important to monitor vitamin A status in nations where preformed vitamin A intake is high because of consumption of animal source foods (e.g., liver, dairy, eggs), fortified foods (e.g., milk, cereals, oil, sugar, margarine), or vitamin supplements (e.g., one-a-day multivitamins) to ensure the population does not reach hypervitaminosis A. To accurately assess population status and evaluate interventions aimed at improving vitamin A status, accurate assessment methods are needed. The primary storage site of vitamin A is the liver; however, routinely obtaining liver samples from humans is impractical and unethical. Isotope dilution using deuterium- or (13)C-labeled retinol is currently the most sensitive indirect biomarker of vitamin A status across a wide range of liver reserves. The major drawback to its application is the increased technicality in sample analysis and data calculations when compared to less sensitive methodology, such as serum retinol concentrations and dose response tests. Two main equations have emerged for calculating vitamin A body pool size or liver concentrations from isotope dilution data: the "Olson equation" and the "mass balance equation." Different applications of these equations can lead to confusion and lack of consistency if the underlying principles and assumptions used are not clarified. The purpose of this focused review is to describe the evolution of the equations used in retinol stable-isotope work and the assumptions appropriate to different applications of the test. Ultimately, the 2 main equations are shown to be fundamentally the same and differ only in assumptions made for each specific research application.


Assuntos
Hipervitaminose A/diagnóstico , Fígado/metabolismo , Modelos Biológicos , Avaliação Nutricional , Estado Nutricional , Deficiência de Vitamina A/diagnóstico , Vitamina A , Algoritmos , Isótopos de Carbono , Deutério , Humanos , Hipervitaminose A/sangue , Hipervitaminose A/metabolismo , Técnicas de Diluição do Indicador , Vitamina A/sangue , Vitamina A/metabolismo , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/metabolismo
7.
Ann Am Thorac Soc ; 11(8): 1244-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25188737

RESUMO

Hypercalcemia is a rare complication of hypervitaminosis A. We report a pediatric patient with cystic fibrosis (CF) and pancreatic insufficiency who was found to have hypervitaminosis A causing hypercalcemia, complicated by nephrocalcinosis and renal impairment. The patient is a 4-year-old girl with pancreatic-insufficient CF, gastroesophageal reflux, oral aversion, and failure to thrive requiring gastrostomy tube placement. She was prescribed Source CF vitamins, but rarely received the full dose, due to emesis and intolerance. She had routine annual labs that revealed hypercalcemia with elevated blood urea nitrogen and creatinine, which were not present in her previous annual labs. Upon further questioning, her mother reported that she seemed more fatigued for a few weeks, had abdominal pain, and was urinating more frequently. Upon admission to the hospital, laboratory results revealed elevated HCO3, while serum levels of potassium, phosphorus, and albumin were within normal limits. Vitamin D (25-hydroxy) level was low, and vitamin A level was elevated. Extensive metabolic and hormonal workup for the etiology of the hypercalcemia revealed evidence of chronic renal insufficiency and elevated vitamin A levels. She had a renal ultrasound that revealed bilateral nephrocalciosis. Diagnosis of chronic hypervitaminosis A complicated by hypercalcemia was made and was managed by holding vitamin A supplements, aggressive diuresis, and prednisolone. This case emphasizes the importance of regular vitamin A monitoring in patients with CF. There is a wide variability for the lowest intake required to cause toxicity, and the lower limit to cause toxicity has not been determined.


Assuntos
Cálcio/sangue , Fibrose Cística/complicações , Hipercalcemia/etiologia , Hipervitaminose A/complicações , Vitamina A/sangue , Pré-Escolar , Fibrose Cística/sangue , Feminino , Humanos , Hipercalcemia/sangue , Hipervitaminose A/sangue
8.
Food Chem Toxicol ; 50(6): 2106-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22426357

RESUMO

Intoxication from vitamin D supplements has been rarely reported but, nowadays, it occurs more frequently. 3-epi-25-OH-D(3) is highly prevalent in adults and it is considered of biological relevance. We report a case of vitamin D toxicity with hypercalcemia, acute renal failure and hypervitaminosis A after consuming an over-the-counter vitamin D supplement. Our data suggest that the contribution of 3-epi-25-OH-D(3) is not altered during vitamin D toxicity, although the serum levels of 25-OH-D(3) and 3-epi-25-OH-D(3) may display a different rate of clearance. The patient also displayed hypervitaminosis A unrelated to diet, possibly caused by renal failure related to the hypercalcemia induced by vitamin D toxicity. Because of the increasing use of over-the-counter vitamin D supplements and the potential iatrogenic hypercalcemia related to hypervitaminosis A, the present case highlights the importance of evaluating both the use of (non-) prescribed medication and vitamin A status during vitamin D toxicity.


Assuntos
Calcifediol/sangue , Hipercalcemia/induzido quimicamente , Hipervitaminose A/induzido quimicamente , Vitamina D/efeitos adversos , Vitaminas/efeitos adversos , 25-Hidroxivitamina D 2/sangue , Injúria Renal Aguda/induzido quimicamente , Cromatografia Líquida de Alta Pressão , Suplementos Nutricionais , Feminino , Humanos , Hipercalcemia/sangue , Hipervitaminose A/sangue , Erros Médicos , Pessoa de Meia-Idade , Controle de Qualidade , Vitamina A/sangue
9.
Bone ; 31(6): 685-9, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12531562

RESUMO

Excessive intake of vitamin A has been associated with an increased risk of hip fracture in humans. This finding has raised the question of whether long-term intake of relatively moderate doses ("subclinical" hypervitaminosis A) contributes to fracture risk. Although it has been known for more than half a century that toxic doses of vitamin A lead to spontaneous fractures in rats, the lowest intake that induces adverse effects is not known, and the result of exposure to excessive doses that do not cause general toxicity has been rarely investigated. In this study, mature female rats were fed a standard diet with 12 IU vitamin A/g pellet (control, C), or standard diet supplemented with either 120 IU ("10 x C") or 600 IU ("50 x C") vitamin A/g pellet for 12 weeks. Fifteen animals were included in each group. The supplemented diets correspond to a vitamin A intake of approximately 1800 IU/day and 9000 IU/day, respectively. The latter dose is about one third of that previously reported to cause skeletal lesions. At the end of the study, serum retinyl esters were elevated 4- (p < 0.01) and 20-fold (p < 0.001) and the total amount of liver retinoid had increased 3- (p < 0.001) and 7-fold (p < 0.001) in the 10 x C and 50 x C group, respectively. The animals showed no clinical signs of general toxicity, and there were no significant bone changes in the 10 x C group. However, in the 50 x C group, a characteristic thinning of the cortex (cortical area -6.5% [p < 0.001]) and reduction of the diameter of the long bones were evident (bone cross-sectional area -7.2% [p < 0.01] at the midshaft and -11.0% [p < 0.01] at the metaphysis), as measured by peripheral quantitative computed tomography. In agreement with these data and a decreased polar strength strain index (-14.0%, p < 0.01), the three-point bending breaking force of the femur was reduced by 10.3% (p < 0.01) in the 50 x C group. These data indicate that the negative skeletal effects appear at a subchronic vitamin A intake of somewhere between 10 and 50 times the standard diet. This level is considerably lower than previously reported. Our results suggest that long-term ingestion of modest excesses of vitamin A may contribute to fracture risk.


Assuntos
Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Hipervitaminose A/metabolismo , Animais , Fenômenos Biomecânicos , Feminino , Fraturas Ósseas/induzido quimicamente , Fraturas Ósseas/metabolismo , Hipervitaminose A/sangue , Ratos , Ratos Sprague-Dawley , Retinoides/sangue , Retinoides/metabolismo , Fatores de Risco , Tomografia Computadorizada por Raios X
10.
J Bone Miner Res ; 16(12): 2306-12, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11760846

RESUMO

Hypervitaminosis A is sometimes associated with abnormalities of calcium metabolism and bone mineral status. A recent study found a negative association between reported dietary vitamin A intake and bone mineral density (BMD). Some segments of the U.S. population have high fasting serum retinyl ester concentrations, a physiological marker that may reflect high and possibly excessive vitamin A intake. We examined the association between fasting serum retinyl esters and BMD in the Third National Health and Nutrition Examination Survey, 1988-1994 (NHANES III), a large, nationally representative sample of the U.S. population. BMD was measured for the femoral neck, trochanter, intertrochanter, and total hip on all nonpregnant participants aged > or = 20 years; 5,790 participants also had complete data on fasting serum retinyl esters and covariates including age, body mass index (BMI), smoking, alcohol consumption, dietary supplement use, diabetes, physical activity, and, among women, parity, menopausal status, and the use of oral contraceptives or estrogen-replacement therapy. The sample included non-Hispanic white, non-Hispanic black, and Mexican American men and women. We examined the association between fasting serum retinyl esters and BMD at each site, controlling for covariates with multiple linear regression. We examined the association with osteopenia and osteoporosis with multiple logistic regression. Although the prevalences of high fasting serum retinyl esters concentration and low BMD were both substantial in this sample, there were no significant associations between fasting serum retinyl esters and any measure of bone mineral status.


Assuntos
Ésteres/sangue , Hipervitaminose A/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Doenças Ósseas Metabólicas/sangue , Feminino , Fêmur/fisiopatologia , Colo do Fêmur/fisiopatologia , Humanos , Hipervitaminose A/fisiopatologia , Masculino , Pessoa de Meia-Idade , Programas Nacionais de Saúde , Inquéritos Nutricionais , Osteoporose/sangue , Vigilância da População , Vitamina A/sangue
11.
Arch Pediatr ; 3(9): 888-90, 1996 Sep.
Artigo em Francês | MEDLINE | ID: mdl-8949352

RESUMO

BACKGROUND: Patients with chronic renal failure are at risk of vitamin A intoxication, a risk that must be evoked when unexplained hypercalcemia occurs. CASE REPORT: An 8 year-old boy with Alagille syndrome and chronic renal failure was admitted because of general deterioration, and bone pain. Severe hypercalcemia (3.9 mmol/L) was present. Serum phosphate, parathyroid hormone and 25 OH D3 levels were normal; 1-25 (OH)2 D3 levels were undetectable. Hypercalcemia was attributed to vitamin A intoxication, due to the administration of a mean daily dose of 12000 IU of vitamin A for at least 2 years. The diagnosis was confirmed by high plasma levels of retinol (1475 micrograms/L). Hypercalcemia only partially responded to treatment with bisphosphonates, calcitonin and dialysis with low calcium dialysate. Serum vitamin A levels remained elevated one month after vitamin A withdrawal. The boy died two months after admission from atrioventricular block. CONCLUSION: Vitamin A administration induces a high risk of intoxication in patients with chronic renal failure. Serum vitamin A concentrations are elevated in these patients, because of decreased renal metabolism of retinol, and vitamin A supplements must be avoided.


Assuntos
Hipercalcemia/etiologia , Hipervitaminose A/sangue , Falência Renal Crônica/complicações , Síndrome de Alagille/complicações , Criança , Humanos , Hipercalcemia/sangue , Hipercalcemia/diagnóstico , Hipercalcemia/terapia , Masculino
12.
Am J Clin Nutr ; 49(1): 112-20, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2911996

RESUMO

We studied the relationships of supplemental and total vitamin A and supplemental vitamin E intake with fasting plasma biochemical indicators of vitamin A and vitamin E nutritional status among 562 healthy elderly people (aged 60-98 y) and 194 healthy young adult (aged 19-59 y) volunteers. All subjects were nonsmokers. For the young adults, plasma retinol was significantly greater in males than in females (p less than 0.01); retinol was not related to supplemental vitamin A intake for either group. Fasting plasma retinyl esters demonstrated a significant increase with vitamin A supplement use. For supplemental vitamin A intakes of 5001-10,000 IU/d, a 2.5-fold increase over nonusers in fasting plasma retinyl esters was observed for elderly people (p less than 0.05) and a 1.5-fold increase for young adults (p greater than 0.20). For elderly people, greater fasting plasma retinyl esters were associated with long-term vitamin A supplement use (greater than 5 y) and biochemical evidence of liver damage. Elderly people who take vitamin A supplements may be at increased risk for vitamin A overload.


Assuntos
Envelhecimento/sangue , Carotenoides/sangue , Colesterol/sangue , Alimentos Fortificados , Proteínas de Ligação ao Retinol/sangue , Vitamina A/análogos & derivados , Vitamina A/administração & dosagem , Vitamina A/sangue , Vitamina E/administração & dosagem , Vitamina E/sangue , Idoso , Idoso de 80 Anos ou mais , Diterpenos , Jejum , Feminino , Humanos , Hipervitaminose A/sangue , Hipervitaminose A/etiologia , Masculino , Pessoa de Meia-Idade , Proteínas Plasmáticas de Ligação ao Retinol , Ésteres de Retinil
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA