Serum Retinol Levels Research Articles

The Effect of a Maternal Double Megadose of Vitamin A Supplement on Serum Levels of Retinol in Children Aged under Six Months

Objective. To measure concentrations of serum retinol in children after the use of maternal vitamin A double megadose supplements. Design. Randomized controlled clinical trial. Setting. The study was conducted at two maternity hospitals in the city of Recife, in the northeast region of Brazil between August 2007 and June 2009. Subjects and Methods. 276 children/mothers were recruited after birth and the women received a 200,000 IU capsule of vitamin A. After ten days they were randomly assigned to two treatment groups. One group received a second 200.000 IU capsule, while the other received a placebo. The concentrations of retinol in the serum of the children from each group were measured at 2, 4, and 6 months. Results. 173 children completed the study. There was no difference between the two treatment groups (P = 0.514). The mean base retinol level was lower than that at four and six months (P < 0.001). Conclusions. The maternal double megadose supplement had no additional effect on the serum retinol levels of the children, although concentrations of retinol in the children rose in the first six months of life. This trial is registered with NCT00742937.

Vitamin A deficiency: An eye sore

Vitamin A deficiency is a major cause of childhood mortality and morbidity in India and other developing countries. The ocular manifestations of vitamin A are collectively called xerophthalmia and range from conjunctival xerosis to severe blinding complications such as keratomalacia. Vitamin A deficiency exists as a major public health nutrition problem among preschool-aged children, especially in the South East Asian region, as well as among the pregnant and lactating women. Deficiency can be diagnosed by the ocular manifestations such as Bitot's spots, serum retinol levels, and conjunctival impression cytology (CIC). Improving vitamin A status in the diet or by periodic administration of vitamin A to children can reduce both mortality and blindness. This review is an attempt to highlight the ocular manifestations of vitamin A deficiency, its prevalence, treatment, and preventive strategies.

Antioxidant Levels at Diagnosis in Childhood Acute Lymphoblastic Leukemia

To measure serum zinc, selenium, retinol and tocoferol levels at diagnosis of pediatric acute lymphoblastic leukemia (ALL) and to compare it to that of a control population. Correlation was made with episodes of febrile neutropenia during the first 8 wk of therapy. Fasting levels of serum zinc, selenium, retinol and tocoferol were measured in 45 children diagnosed with acute lymphoblastic leukemia and in 20 healthy controls. Lower levels of baseline selenium and tocoferol were noted in patients who developed febrile neutropenia compared to the patients who did not (p = 0.022 and 0.026 respectively). Serum retinol was also lower in patients who developed sepsis when compared to those who did not. Supplementation of antioxidants may be considered in clinical trials aiming at reducing infection related morbidity and mortality.

Exome Analysis Identified a Novel Mutation in the RBP4 Gene in a Consanguineous Pedigree with Retinal Dystrophy and Developmental Abnormalities

Retinitis Pigmentosa (RP) is a common form of retinal degeneration characterized by photoreceptor degeneration and retinal pigment epithelium (RPE) atrophy causing loss of visual field and acuities. Exome sequencing identified a novel homozygous splice site variant (c.111+1G>A) in the gene encoding retinol binding protein 4 (RBP4). This change segregated with early onset, progressive, and severe autosomal recessive retinitis pigmentosa (arRP) in an eight member consanguineous pedigree of European ancestry. Additionally, one patient exhibited developmental abnormalities including patent ductus arteriosus and chorioretinal and iris colobomas. The second patient developed acne from young age and extending into the 5th decade. Both patients had undetectable levels of RBP4 in the serum suggesting that this mutation led to either mRNA or protein instability resulting in a null phenotype. In addition, the patients exhibited severe vitamin A deficiency, and diminished serum retinol levels. Circulating transthyretin levels were normal. This study identifies the RBP4 splice site change as the cause of RP in this pedigree. The presence of developmental abnormalities and severe acne in patients with retinal degeneration may indicate the involvement of genes that regulate vitamin A absorption, transport and metabolism.

Voriconazole-induced photosensitivity: photobiological assessment of a case series of 12 patients

Voriconazole, a broad-spectrum triazole antifungal agent increasingly used to treat aspergillosis, has been linked with acute photosensitivity and skin carcinogenesis. The action spectrum of the photosensitivity is unknown, while an indirect retinol effect secondary to the antifungal's impact on CYP450 enzymes has been proposed to contribute to the underlying mechanism. To perform a detailed photobiological assessment of the photosensitivity presenting in a series of 12 patients treated with voriconazole. Minimal erythemal dose thresholds (MED) to narrow wavebands of ultraviolet (UV) A, UVB and visible light were determined. Provocation testing was performed to broadband UVA (310-400 nm) and to solar-simulated radiation (SSR) (290-400 nm). Patients underwent routine photopatch testing and laboratory investigations including serum vitamin A (retinol). Patients (eight men, four women; median age 54years, range 40-63) experienced moderate-severe cutaneous erythema (n = 12), burning pain (n=5), itching (n=3), scaling (n=5), vesiculation (n=5) and oedema (n=1) following sunlight exposure; increased lentigines (n=4) and actinic cheilitis (n = 4) were also observed. While the majority (n=8) of patients showed normal MED thresholds to monochromator phototesting to UVB, UVA and visible light, a low MED to UVA was observed in four patients. Repeated provocation testing with broadband UVA and SSR provoked an abnormal erythema in eight and 10 patients, respectively. Serum retinol levels were mildly elevated in two patients but normal in the majority. UVA sensitivity is the predominant finding in acute voriconazole-induced photosensitivity. We found little evidence of elevated circulating retinol as the causal factor. Patients with voriconazole-induced photosensitivity require education in appropriate UVA protective measures in addition to consideration of skin surveillance for malignant sequelae.

Abstract 15: Interaction between retinol transporter genes and alcohol on the risk of head and neck cancer.

Abstract Background: Alcohol is a major risk factor for head and neck cancer (HNC). The metabolism of ethanol can disrupt the metabolism of retinoic acid because the two pathways share some key enzymes. Retinoic acid is involved in cell growth, differentiation, and apoptosis, which when dysregulated may lead to the development of cancer. A previous genome-wide association study reported an association between single nucleotide polymorphisms (SNPs) in two retinol transporter genes (TTR and RBP4) and serum retinol level (1). The current study evaluates the interaction between alcohol consumption and SNPs in TTR and RBP4 on the risk of HNC. Methods: 223 incident cases of HNC and 214 sex- and age- matched controls were recruited from the department of otolaryngology and department of stomatology. In-person interviews were conducted to collect information on the use of alcohol, cigarette, and betel quid. Three tag-SNPs of TTR and 8 tag-SNPs of RBP4 were genotyped using the Taqman-based real-time PCR method or mass spectrometry-based detection method. Unconditional logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) of HNC risk associated with each SNP and to evaluate the joint influence of SNPs and alcohol consumption on HNC risk, adjusted for age, sex, education, cigarette smoking and betel quid use. Results: No significant association between HNC risk and any of the 11 tag-SNPs was observed. However, three SNPs of RBP4 appeared to modify the relationship between alcohol consumption and HNC risk. After combining the three SNPs into a polygenic risk score, the results showed that those who drank alcohol daily had a different risk of HNC, depending on the number of variant alleles (0 to 2 variant alleles: OR=1.2, 95% CI: 0.7-2.1; 3 or more variant alleles: OR=2.9, 95% CI: 1.1-7.9; interaction P-value = 0.01) Conclusion: The association between HNC risk and alcohol consumption is modified by the polymorphisms of RBP4. Citation Format: Jeffrey S. Chang, Jenn-Ren Hsiao, Tung-Yiu Wong, Sen-Tien Tsai, Chun-Yen Ou, Hung-I Lo, Cheng-Chih Huang, Wei-Ting Lee, Ken-Chung Chen, Jehn-Shyun Huang, Yi-Hui Wang, Ya-Ling Weng, Han-Chien Yang. Interaction between retinol transporter genes and alcohol on the risk of head and neck cancer. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 15.

Global Efforts to Address Severe Acute Malnutrition

476 5. C hildhood malnutrition encompasses a plethora of nutritional disorders that include stunting, underweight, wasting, severe acute malnutrition (SAM), and micronutrient deficiency disorders. Overweight and obesity, at the other end of the nutritional spectrum, are also manifestations of childhood malnutrition. Nearly 24 million children (younger than 5 years) worldwide experience SAM. The vast majority is located in Africa and Asia (8 million are in India alone). A child with SAM is 10 times more likely to die than a wellnourished child. SAM is one of the top 3 nutrition-related causes of death in children younger than 5 years. Estimates of deaths directly attributable to SAM varied from 0.5 to 2 million annually. Moderate and severe child malnutrition account for 40% to 50% of all deaths in children younger than 5 years. If the United Nations Millennium Development Goals (http://www.un.org/millennium goals) of reducing children malnutrition and mortality by 50% by 2015 are to be met, SAM needs to be prevented and controlled effectively.

Assessment of the Relative Dose‐Response Test as Indicators of Hepatic Vitamin A Stores in Various Stages of Chronic Liver Disease

Hepatic vitamin A stores should be the best early indicator of vitamin A status because more than 90% of total body vitamin A is stored in the liver. The objective of the present study was to evaluate the hepatic vitamin A stores in all stages of chronic liver disease (CLD), including chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). One hundred forty-four patients (age 55.34 ± 9.38 years) were evaluated in a cross-sectional study. Vitamin A nutrition status was analyzed by serum retinol levels and relative dose-response (RDR) method. Patients with cholestasis were excluded from the sample group. Biochemical, clinical, and anthropometric evaluations were performed. Vitamin A deficiency (VAD) was detected in 51.4% of all patients. Patients with adequate levels of serum retinol presented adequate liver vitamin A reserves; in contrast, nearly half the patients with low serum retinol levels presented adequate levels of retinol in the liver, although none of the patients with hepatitis had this condition. Therefore, the effectiveness of the RDR method for evaluating vitamin A nutrition status was limited in patients with cirrhosis and HCC, perhaps due to the advanced age of these patients, since those in the chronic hepatitis group, who were younger, responded adequately to the test. Thus, the RDR method should be modified when applied to later stages of CLD, considering the time and dose of retinyl palmitate supplementation, as VAD may be a risk factor for the progression of the disease.

The Effects of Two Maternal Vitamin A Supplementation Regimens on Serum Retinol in Postpartum Mothers: A Randomised Controlled Trial in Brazil

Objective. To test whether the serum retinol level in mothers supplemented with 400,000 IU of vitamin A is higher than in those supplemented with 200,000 IU and to estimate duration of the protective effect of vitamin A supplementation in the serum retinol level. Methods. Double-blind, randomised controlled trial performed in two hospitals in the state of Pernambuco in northeast Brazil. Three hundred twelve mothers were recruited immediately postpartum. All women received a capsule containing 200,000 IU of vitamin A, and 10 days after delivery, they were randomly assigned to one of two treatment groups. One group received a second capsule containing vitamin A and the other group received a placebo. Each group was invited back after 2, 4, and 6 months for serum retinol analyses. Results. No difference was found between the two groups in serum maternal retinol concentration at 2 months (2.13 versus 2.03 μmol/L), 4 months (2.20 versus 2.24 μmol/L) or 6 months (2.29 versus 2.31 μmol/L). Because there was no further effect and because this population has a level of vitamin A deficiency considered mild, our results do not support a proposal to increase the dosing schedule for vitamin A in postpartum women as recommended by the IVACG.

Severe Measles, Vitamin A Deficiency, and the Roma Community in Europe

Severe Measles, Vitamin A Deficiency, and the Roma Community in Europe

The association of carotid intima media thickness with retinol binding protein-4 and total and high molecular weight adiponectin in type 2 diabetic patients.

BackgroundThe aim of this study was to investigate whether carotid intima media thickness (CIMT) is associated with serum level of retinol- binding protein-4 (RBP4) and total and high molecular weight (HMW) adiponectin in type 2 diabetes (T2DM) without clinical symptom of atherosclerotic disease.Method101 type 2 diabetic patients (mean age, 53.63 ± 8.42 years) and 42 body mass index (BMI) matched control (mean age 50.1 ± 8.4) were recruited. The CIMT was assessed by using B-mode ultrasonography, while serum levels of RBP4 and total and HMW adiponectin were measured by using enzyme linked immunosorbant assay (ELISA). Linear regression analysis was performed with CIMT as dependent variable and adipokines and cardio metabolic risk factors as independent variables.ResultThe CIMT was higher in diabetic group compared to control group (p <0.05). The mean concentration of RBP4 and total and HMW adiponectin did not differ between two groups.Age (B = 0.44 P <0.05), blood pressure (B = 0.37 P = <0.05), waist circumference (B = −0.21 P <0.05) and TG (B = 0.1 P <0.05) were identified as independent predictors for CIMT in diabetic group, while RBP4 and adiponectin were not associated with CIMT neither in diabetic group nor in control group.ConclusionIn conclusion, the present study showed that serum levels of RBP4 or total and HMW adiponectin were not potential predictors of CIMT in type 2 diabetic patients who exposed to this risk factor at least for nine years.

Increased Exposure of Vitamin A by Chrysanthemum morifolium Ramat Extract in Rat Was Not via Induction of CYP1A1, CYP1A2, and CYP2B1

The aim of this study was to investigate the effect of Chrysanthemum morifolium Ramat (CM) extract on the pharmacokinetics of retinol and activities of cytochrome P450s (CYP450s) related to retinoid metabolism. Rats were treated with CM extract for 15 d. Plasma concentrations of retinol were measured following oral administration of retinol (45 mg/kg). Basal levels of retinol and retinoic acid in serum and liver were also measured. 7-Ethoxyresorufin-O-deethylase activity, phenacetin-O-deethylase activity, and 7-pentoxyresorufin-O-deethylase activities were used to assay the activities of CYP1A1, CYP1A2, and CYP2B1 in hepatic microsomes of rats, respectively. Protein expressions of the 3 CYP450s were measured by western blot. Our studies demonstrated that CM extract dose-dependently increased basal level of retinol in serum. In pharmacokinetic experiment, CM extract dose-dependently increased plasma concentrations of retinol after oral administration of retinol to rats treated with CM extract. But activities and expressions of CYP1A1, CYP1A2, and CYP2B1 in hepatic microsomes of rats were also induced by CM extract.

Retinol Assessment Among Women and Children in Sahelian Mobile Pastoralists

Micronutrient deficiencies are widespread in developing countries, particularly in remote communities such as mobile pastoralists. The nutritional and vitamin A status of this population is not well-documented in Chad. This study assessed serum retinol levels among women and children under five-year-old in nomadic and semi-nomadic pastoralist and rural-settled communities, who are similarly exposed to risk factors such as gastrointestinal parasitic infection, anaemia and emaciation. The novel method of portable fluorometry was used for the first time to measure β-carotene and retinol levels in a pastoral nomadic area. Moderate level blood retinol deficiency (<0.7 μmol/L) was observed in 5% (CI 1–11) of nomadic, 29% (CI 13–45) of semi-nomadic and 22% (CI 8–35) of sedentary women. In children, 1% (CI 0.1–4), 17% (CI 9–25) and 28% (CI 18–39), respectively, had moderate level blood retinol deficiency. In nomadic communities, women and children had blood retinol levels close to normal. Deficiency of retinol was strongly linked with lifestyle (nomadic, semi-nomadic and settled) among women and lifestyle and age among children. The results support an ecological linkage between human retinol levels and livestock milk retinol. This study shows the feasibility of portable retinol and β-carotene measurement in human blood as well as human and animal milk under remote field conditions, but the approach requires further validation.

Sun-dried cowpeas and amaranth leaves recipe improves β-carotene and retinol levels in serum and hemoglobin concentration among preschool children

Vitamin A deficiency (VAD) and anemia are major challenges among children and expecting and lactating mothers in developing countries. Intervention with locally available dark green leafy vegetables (DGLV) is more sustainable to eradicate VAD, being cost-effective and readily adaptable to local communities. DGLV contain high levels of iron and β-carotene (BC) and therefore useful in fighting VAD and anemia. Since DGLVs are season-dependent sun-drying enables their availability during low seasons. However, their contribution to the bioavailability of BC and the improvement of hemoglobin are not well understood. The study therefore investigated the effect of consuming cooked recipe consisting of sun-dried amaranth and cowpea leaves on the levels of BC, retinol, and hemoglobin in preschool children from Machakos District, a semiarid region in Kenya. Vegetables were purchased from local vegetable market, with some sun-dried in an open shade. Levels of BC and retinol in serum and BC in fresh and processed vegetables were determined by a HPLC method and hemoglobin using a portable Hemocue Analyzer. All-trans-BC levels in uncooked fresh cowpea and amaranth leaves were 806.0 μg/g and 599.0 μg/g dry matter, respectively, while the dehydration and cooking processes retained the β-carotene levels at over 60 %. Consumption of the dehydrated vegetables significantly improved both serum BC and retinol levels (p < 0.05), while the baseline hemoglobin levels improved by 4.6 %. The study has shown that intervention with locally available sun-dried vegetables improves the bioavailability of BC, retinol, and hemoglobin levels among preschool children.

Abstract 2627: Polymorphisms of retinol transporter genes and risk of head and neck cancer

Abstract Background: Retinoic acid is important for cell growth, differentiation, and apoptosis, which when dysregulated may predispose the development of cancer. Retinoic acid metabolism can be influenced by ethanol, cigarette smoking, and areca nut, the three major risk factors of head and neck cancer (HNC). A previous genome-wide association study reported an association between serum retinol level and two single nucleotide polymorphisms (SNPs) in two retinol transporter genes (TTR rs1667255 and RBP4 rs10882272) (1). The current study assesses the association between these two SNPs and HNC risk. Methods: 133 incident cases of HNC and 128 sex- and age- matched controls were recruited from the department of otolaryngology and department of stomatology. Data on the use of alcohol, cigarette, and areca nut were ascertained through in-person interview. Genotyping of TTR rs1667255 and RBP4 rs10882272 was performed using the Taqman-based real-time PCR method. Unconditional logistic regression was performed to estimate HNC risk associated with the two SNPs. Results: No association between HNC risk and TTR rs1667255 or RBP4 rs10882272 was observed. However, the two SNPs appeared to modify the relationship between alcohol consumption and HNC risk. There was an increased risk of HNC associated with daily alcohol drinking only among subjects with the “high serum retinol genotypes” (CC for TTR rs1667255: odds ratio (OR) = 4.6, 95 confidence interval (CI): 1.3-16.3; TT for RBP4 rs10882272: OR = 2.3, 95% CI: 1.2-4.4). While daily alcohol drinking was not associated with an increased risk of HNC among subjects with the “low serum retinol genotypes” (AA or AC for TTR rs1667255: OR = 1.4, 95% CI: 0.7-2.9; TC or CC for RBP4: OR = 0.7, 95% CI: 0.1-3.6). Conclusion: The association between alcohol consumption and HNC risk is modified by the polymorphisms of retinol transporter genes. Reference: 1. Mondul AM, Yu K, Wheeler W, et al. Genome-wide association study of circulating retinol levels. Human molecular genetics 2011;20:4724-31. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2627. doi:1538-7445.AM2012-2627

Variability of Vitamin A and Carotenoid Status Among Women of Childbearing Age

ObjectiveAnimal models suggest vitamin A exposure at subteratogenic levels may contribute to behavioral problems in offspring. We aimed to determine whether serum levels of retinol retinyl palmitate and carotenoids were higher among potentially fertile supplement users.Methods100 women completed a dietary history questionnaire. Blood samples were analyzed for retinyl palmitate, α‐carotene, β‐carotene, lutein, and zeaxanthin. Pearson correlations between reported intake and serum levels were calculated, and serum levels were compared among supplement users and non‐users.ResultsMean levels and IQR of retinols and carotenes were: retinyl palmitate 0.019 (0.10–0.20), vitamin A 0.54 (0.45–0.59), α‐carotene 77.15 (36.5–95.5), β‐carotene 228.34 (94.00–298.50), zeaxanthin 20.29 (12.00–26.50). 31 women took multi‐vitamins containing vitamin A (mean 4332 IU). Serum levels of retinol and carotenoids were highly variable. We observed elevated levels of retinol (n=1) α‐carotene (n=21) level, β‐carotene (n=14), and lutein (n=5). Serum β‐carotene was correlated with β‐carotene (mg/d) from supplements (r= 0.21, p = 0.03).ConclusionVitamin A and carotenoid status of potentially fertile women was variable. Serum β‐carotene levels were associated with supplement use whereas retinol levels were not distinguishable between users and non‐users.

Effect on Infant Illness of Maternal Supplementation With 400 000 IU Vs 200 000 IU of Vitamin A

Postpartum vitamin A supplementation is a strategy used to combat vitamin A deficiency and seems to reduce maternal/infant morbidity and mortality. However, studies have shown that a dose of 200 000 IU (World Health Organization [WHO] protocol) does not seem to provide adequate retinol levels in maternal breast milk, infant serum, and infant tissue. The objective of this study was to compare the effect of postpartum maternal supplementation with 400 000 IU (International Vitamin A Consultative Group protocol) compared with 200 000 IU of vitamin A on infant morbidity. This was a randomized controlled, triple-blinded clinical trial conducted at 2 public maternity hospitals in Recife in northeastern Brazil. There were 276 mother-child pairs that were allocated to 2 treatment groups: 400 000 IU or 200 000 IU of vitamin A. They were followed up for >6 months to evaluate infant morbidity. Fever (rate ratio [RR]: 0.92 [95% confidence interval (CI): 0.75-1.14]), diarrhea (RR: 0.96 [95% CI: 0.72-1.28]), otitis (RR: 0.94 [95% CI: 0.48-1.85]), acute respiratory infection (RR: 1.03 [95% CI: 0.88-1.21]), the need for intravenous rehydration (RR: 2.08 [95% CI: 0.64-2.07]), and the use of antibiotic treatment (RR: 0.80 [95% CI: 0.43-1.47]) did not differ significantly between the 2 treatment groups. Our findings suggest that postpartum maternal supplementation with 400 000 IU of vitamin A does not provide any additional benefits in the reduction of illness in children aged <6 months; therefore, we do not support the proposal to increase the standard vitamin A dose in the existing WHO protocol.

Effect of Vitamin A Fortified Milk Intake on Total Body Vitamin A Stores in Mexican Preschoolers

In Mexico, vitamin A deficiency (VAD) is a public health problem for preschool children. Vitamin A (VA) fortified milk (Liconsa) is distributed nationally to fight VAD, nevertheless its effect has yet not been assessed. The aim of this study was to assess the effect of daily intake of VA fortified milk on the total body VA (TBVA) stores of preschoolers.We conducted a randomized controlled clinical trial in Mexico to assess the effect of daily intake of 250 mL of VA fortified Liconsa milk for 12 weeks on VA status of 24 VA‐deficient preschoolers. Subjects were randomly allocated to treatment (n=11) or control (n=13) groups respectively. TBVA stores were calculated using the Olson equation at baseline and three months after daily intake of VA fortified “Liconsa” milk.TBVA stores of the treatment group had a significant increase compared to their baseline value (P&lt;0.05) and stores had a significant difference of 0.75 mmol in treatment vs control groups (P=0.01). Serum retinol concentration was significantly reduced compared to its baseline value in the control group (P&lt;0.05) and serum retinol was 0.291μmol/L greater in the treatment vs control group (P=0.01).Daily intake of vitamin A fortified “Liconsa” milk during 12 weeks, significantly increased TBVA stores and serum retinol levels of Mexican preschoolers.Study supported by the IAEA. LTV received a fellowship from CONACyT.Grant Funding Source : IAEA‐CONACyT

Independent association of serum retinol and β‐carotene levels with hyperuricemia: A national population study

Uses of synthetic vitamin A derivatives (e.g., isotretinoin used for severe acne) and high doses of preformed vitamin A have been implicated in the pathogenesis of hyperuricemia and gout, whereas a trial reported that β-carotene may lower serum uric acid (UA) levels. We evaluated the potential population impact of these factors on serum UA in a nationally representative sample of US adults. Using data from 14,349 participants ages ≥20 years in the Third National Health and Nutrition Examination Survey (1988-1994), we examined the relationship between serum retinol, β-carotene, and UA levels using weighted linear regression. Additionally, we examined the relationship with hyperuricemia using weighted logistic regression. Serum UA levels increased linearly with increasing serum retinol levels, whereas serum UA levels decreased with increasing serum β-carotene levels. After adjusting for age, sex, dietary factors, and other potential confounders, the serum UA level differences from the bottom (referent) to the top quintiles of serum retinol levels were 0, 0.16, 0.32, 0.43, and 0.71 mg/dl (P for trend <0.001), and for β-carotene were 0, -0.15, -0.29, -0.27, and -0.40 mg/dl (P for trend <0.001), respectively. Similarly, the multivariate odds ratios of hyperuricemia from the bottom (referent) to top quintiles of serum retinol levels were 1.00, 1.30, 1.83, 2.09, and 3.22 (P for trend <0.001) and for β-carotene were 1.00, 0.85, 0.68, 0.73, and 0.54 (P for trend <0.001), respectively. The graded associations persisted across subgroups according to cross-classification by both serum retinol and β-carotene levels. These nationally representative data raise concerns that vitamin A supplementation and food fortification may contribute to the high frequency of hyperuricemia in the US population, whereas β-carotene intake may be beneficial against hyperuricemia. The use of β-carotene as a novel preventive treatment for gout deserves further investigation.

Flocos desidratados de abóbora na prevenção da carência de vitamina A em pré-escolares de uma creche

OBJETIVO: Esta pesquisa teve como objetivo avaliar a eficácia de flocos desidratados de abóbora na elevação dos níveis séricos de retinol e a resposta relativa à dose em pré-escolares. MÉTODOS: A ingestão de vitamina A foi avaliada por meio de inquérito dietético. Os flocos foram analisados quanto às características microbiológicas e ao conteúdo de carotenoides. As crianças estudadas receberam diariamente 6g do produto no almoço, durante 90 dias. Elas foram submetidas ao teste de resposta relativa à dose no início e no final do estudo. Amostras de sangue foram colhidas em jejum, para análise do retinol sérico por espectro-fotometria, no início do estudo, aos 30 dias de consumo e aos 90 dias. RESULTADOS: Quanto às análises microbiológicas, os flocos encontravam-se adequados para consumo. O nível médio de retinol sérico nas crianças aumentou de M=1,438, DP=0,45µmol/L (tempo 0) para M=1,659, DP=0,51µmol/L (30 dias) e M=1,928, DP=0,70µmol/L (90 dias). No início do estudo, 18,5% das crianças apresentavam níveis de retinol sérico abaixo do ponto de corte de 1,05µmol/L, proporção que caiu para 7,6% depois de 30 dias e para 0% após 90 dias. No final do período de estudo (90 dias) nenhuma criança apresentou resposta relativa à dose positiva. CONCLUSÃO: Os flocos de abóbora são eficazes na elevação do retinol sérico e na reserva hepática da vitamina em pré-escolares.