Fenretinide inhibits vitamin A formation from ß-carotene and regulates carotenoid levels in mice.

N-[4-hydroxyphenyl]retinamide, commonly known as fenretinide, a synthetic retinoid with pleiotropic benefits for human health, is currently utilized in clinical trials for cancer, cystic fibrosis, and COVID-19. However, fenretinide reduces plasma vitamin A levels by interacting with retinol-binding protein 4 (RBP4), which often results in reversible night blindness in patients. Cell culture and in vitro studies show that fenretinide binds and inhibits the activity of ß-carotene oxygenase 1 (BCO1), the enzyme responsible for endogenous vitamin A formation. Whether fenretinide inhibits vitamin A synthesis in mammals, however, remains unknown. The goal of this study was to determine if the inhibition of BCO1 by fenretinide affects vitamin A formation in mice fed ß-carotene. Our results show that wild-type mice treated with fenretinide for ten days had a reduction in tissue vitamin A stores accompanied by a two-fold increase in ß-carotene in plasma (P < 0.01) and several tissues. These effects persisted in RBP4-deficient mice and were independent of changes in intestinal ß-carotene absorption, suggesting that fenretinide inhibits vitamin A synthesis in mice. Using Bco1-/- and Bco2-/- mice we also show that fenretinide regulates intestinal carotenoid and vitamin E uptake by activating vitamin A signaling during short-term vitamin A deficiency. This study provides a deeper understanding of the impact of fenretinide on vitamin A, carotenoid, and vitamin E homeostasis, which is crucial for the pharmacological utilization of this retinoid.

Association between serum retinol and overall and cause-specific mortality in a 30-year prospective cohort study.

How retinol as a clinical indicator of vitamin A status is related to long-term mortality is unknown. Here we report the results of a prospective analysis examining associations between serum retinol and risk of overall and cause-specific mortality. During a 30-year cohort follow-up, 23,797 deaths were identified among 29,104 men. Participants with higher serum retinol experienced significantly lower overall, CVD, heart disease, and respiratory disease mortality compared to men with the lowest retinol concentrations, reflecting 17-32% lower mortality risk (Ptrend < 0.0001). The retinol-overall mortality association is similar across subgroups of smoking intensity, alcohol consumption, body mass index, trial supplementation, serum alpha-tocopherol and beta-carotene concentrations, and follow-up time. Mediation analysis indicated that <3% of the effects of smoking duration and diabetes mellitus on mortality were mediated through retinol concentration. These findings indicate higher serum retinol is associated with lower overall mortality, including death from cardiovascular, heart, and respiratory diseases.

The plasma antioxidant vitamin status of the INTAPP cohort examined: The unsuspected importance of ß-carotene and γ-tocopherol in preeclampsia.

OBJECTIVE: Examine the levels of plasma antioxidant vitamins before and during a treatment with placebo or vitamin E + C supplement to prevent preeclampsia (PE). STUDY DESIGN: Per-protocol analysis of a subset group of pregnant women (n = 295) from the International Trial of Antioxidants for the Prevention of PE (INTAPP) randomized case-control study. Normotensive receiving placebo or vitamins (n = 115 and 87 respectively) were compared to gestational hypertension (GH) without proteinuria (n = 30 and 27) and PE (n = 21 and 15). Vitamin quantification was performed at 12-18, 24-26 and 32-34 weeks of gestation. MAIN OUTCOME MEASURES: Coenzyme (Co) Q10, ß-carotene and vitamins E (α and γ forms) plasma levels. RESULTS: Vitamin E + C supplementation was found to increase the α-tocopherol levels by 40% but was associated with a 57% decrease in the γ-tocopherol isoform for all study groups (p < 0.001). The ß -carotene was lower in the PE than in the normotensive and GH groups (p < 0.001) while the level of CoQ10 remained unaffected. CONCLUSIONS: A more personalized approach that target the suboptimal levels of specific antioxidants without disturbing the α/γ-tocopherol ratio could be a more successful approach to counteract oxidative stress in PE.

ß-Carotene Status Is Associated with Inflammation and Two Components of Metabolic Syndrome in Patients with and without Osteoarthritis.

This study was conducted to investigate the ß-carotene status in osteoarthritis (OA) patients and examine its relationships with the risk of inflammation and metabolic syndrome. OA patients were stratified by obesity based on body fat percentage (obese OA, n = 44; non-obese OA, n = 56), and sixty-nine subjects without OA or obesity were assigned as a non-obese control group. ß-carotene, metabolic parameters, and inflammation status were assessed. Obese OA patients exhibited a significantly higher rate of metabolic syndrome (p = 0.02), abdominal obesity (p < 0.01), and lower ß-carotene status (p < 0.01) compared with non-obese OA and non-obese controls. After adjusting for potential confounders, ß-carotene status (≥0.8 µM) was significantly inversely correlated with the risk of metabolic syndrome (odds ratio = 0.27, p < 0.01), abdominal obesity (odds ratio = 0.33, p < 0.01), high blood pressure (odds ratio = 0.35, p < 0.01), hyperglycemia (odds ratio = 0.45, p < 0.05), and inflammation (odds ratio = 0.30, p = 0.01). Additionally, subjects who had a high ß-carotene status with a low proportion of metabolic syndrome when they had a low-grade inflammatory status (p < 0.01). Obese OA patients suffered from a higher prevalence of metabolic syndrome and lower ß-carotene status compared to the non-obese controls. A better ß-carotene status (≥0.8 µM) was inversely associated with the risk of metabolic syndrome and inflammation, so we suggest that ß-carotene status could be a predictor of the risk of metabolic syndrome and inflammation in patients with and without OA.

The Associations of Plasma/Serum Carotenoids with Alzheimer's Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Multiple lines of evidence indicate protective effects of carotenoids in Alzheimer's disease (AD). However, previous epidemiological studies reported inconsistent results regarding the associations between carotenoids levels and the risk of AD. OBJECTIVE: Our study aims to evaluate the associations of six major members of carotenoids with the occurrence of AD by conducting a systematic review and meta-analysis. METHODS: Following PRISMA guidelines, a comprehensive literature search of PubMed, Web of Science, Ebsco, and PsycINFO databases was conducted, and the quality of each included studies was evaluated by a validated scoring systems. Standardized mean differences (SMD) with 95% confidence intervals (CI) were determined by using a random effects model. Heterogeneity was evaluated by I2 statistics. Publication bias was detected using funnel plots and Egger's test. RESULTS: Sixteen studies, with 10,633 participants were included. Pooled analysis showed significantly lower plasma/serum levels of lutein (SMD = -0.86, 95% CI: -1.67 to -0.05, p = 0.04) and zeaxanthin (SMD = -0.59; 95% CI: -1.12 to -0.06, p = 0.03) in patients with AD versus cognitively intact controls, while α-carotene (SMD = 0.21, 95% CI: -0.68 to 0.26, p = 0.39), ß-carotene (SMD = 0.04, 95% CI: -0.57 to 0.65, p = 0.9), lycopene (SMD = -0.12, 95% CI: -0.96 to 0.72, p = 0.78), and ß-cryptoxanthin (SMD = -0.09, 95% CI: -0.83 to 0.65, p = 0.81) did not achieve significant differences. CONCLUSION: Of six major members of carotenoids, only lutein and zeaxanthin concentrations in plasma/serum were inversely related to the risk of AD. More high-quality longitudinal studies are needed to verify these findings.

Dietary Data in the Malmö Offspring Study-Reproducibility, Method Comparison and Validation against Objective Biomarkers.

Irregular dietary intakes impairs estimations from food records. Biomarkers and method combinations can be used to improve estimates. Our aim was to examine reproducibility from two assessment methods, compare them, and validate intakes against objective biomarkers. We used the Malmö Offspring Study (55% women, 18-71 y) with data from a 4-day food record (4DFR) and a short food frequency questionnaire (SFFQ) to compare (1) repeated intakes (n = 180), (2) intakes from 4DFR and SFFQ (n = 1601), and (3) intakes of fatty fish, fruits and vegetables, and citrus with plasma biomarkers (n = 1433) (3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid [CMPF], ß-carotene and proline betaine). We also combined 4DFR and SFFQ estimates using principal component analysis (PCA). Moderate correlations were seen between repeated intakes (4DFR median ρ = 0.41, SFFQ median ρ = 0.59) although lower for specific 4DFR-items, especially fatty/lean fish (ρ ≤ 0.08). Between-method correlations (median ρ = 0.33) were higher for intakes of overall food groups compared to specific foods. PCA scores for citrus (proline betaine ρ = 0.53) and fruits and vegetables (ß-carotene: ρ = 0.39) showed the highest biomarker correlations, whereas fatty fish intake from the SFFQ per se showed the highest correlation with CMPF (ρ = 0.46). To conclude, the reproducibility of SFFQ data was superior to 4DFR data regarding irregularly consumed foods. Method combination could slightly improve fruit and vegetable estimates, whereas SFFQ data gave most valid fatty fish intake.

Association between Serum Concentration of Carotenoid and Visceral Fat.

Consumption of fruits and vegetables rich in carotenoids has been widely reported to prevent cardiovascular diseases. However, the relationship between serum carotenoid concentrations and visceral fat area (VFA), which is considered a better predictor of cardiovascular diseases than the body-mass index (BMI) and waist circumference, remains unclear. Therefore, we examined the relationship in healthy individuals in their 20s or older, stratified by sex and age, to compare the relationship between serum carotenoid concentrations and VFA and BMI. The study was conducted on 805 people, the residents in Hirosaki city, Aomori prefecture, who underwent a health checkup. An inverse relationship between serum carotenoid concentrations and VFA and BMI was observed only in women. In addition, the results were independent of the intake of dietary fiber, which is mainly supplied from vegetables as well as carotenoids. This suggests that consumption of a diet rich in carotenoids (especially lutein and beta-carotene) is associated with lower VFA, which is a good predictor of cardiovascular disease, especially in women. This study is the first to comprehensively evaluate the association between serum carotenoid levels and VFA in healthy individuals.

Nutritional Controlled Preparation and Administration of Different Tomato Purées Indicate Increase of ß-Carotene and Lycopene Isoforms, and of Antioxidant Potential in Human Blood Bioavailability: A Pilot Study.

The isoforms of lycopene, carotenoids, and their derivatives including precursors of vitamin A are compounds relevant for preventing chronic degenerative diseases such as cardiovascular diseases and cancer. Tomatoes are a major source of these compounds. However, cooking and successive metabolic processes determine the bioavailability of tomatoes in human nutrition. To evaluate the effect of acute/chronic cooking procedures on the bioavailability of lycopene and carotene isoforms in human plasma, we measured the blood levels of these compounds and of the serum antioxidant potential in volunteers after a meal containing two different types of tomato sauce (rustic or strained). Using a randomized cross-over administration design, healthy volunteers were studied, and the above indicated compounds were determined by HPLC. The results indicate an increased bioavailability of the estimated compounds and of the serum antioxidant potential with both types of tomato purée and the subsequently derived sauces (the increase was greater with strained purée). This study sheds light on the content of nutrient precursors of vitamin A and other antioxidant compounds derived from tomatoes cooked with different strategies. Lastly, our study indicates that strained purée should be preferred over rustic purée.

Physiological significance of link between polycyclic aromatic hydrocarbons and serum nutritional biomarkers.

It is well-known that exposure to polycyclic aromatic hydrocarbons (PAH) may cause adverse health impacts. However, there are few investigations assessing the association between PAH exposure and the nutritional status of the general population. Thus, the purpose of this investigation was to assess the correlation between PAH metabolites and nutritional biomarkers in the U.S. general population. From the 2003-2006 National Health and Nutrition Examination Survey, 4,545 eligible participants were included in this cross-sectional study. To assess PAH exposure, ten urinary PAH metabolites were measured. Eleven serum nutritional biomarkers including carotenoids and vitamins were measured. The association between PAH metabolites and serum nutritional biomarkers was investigated using multivariate linear regression models. Increased 2-hydroxyfluorene was inversely correlated with elven serum nutritional biomarkers: α-carotene (ß = -0.529, p < 0.001), ß-cryptoxanthin (ß = -0.968, p < 0.001), cis-ß carotene (ß = -0.149, p < 0.001), lutein and zeaxanthin (ß = -1.188, p < 0.001), retinyl palmitate (ß = -0.145, p < 0.001), retinyl stearate (ß = -0.025, p = 0.006), total lycopene (ß = -1.074, p < 0.001), trans-ß carotene (ß = -2.268, p < 0.001), trans-lycopene (ß = -0.466, p < 0.003), retinol (ß = -0.694, p = 0.004) and 25-hydroxyvitamin D (ß = -1.247, p = 0.007). Increased 3-hydroxyfluorene was inversely correlated with eleven serum nutritional biomarkers: α-carotene (ß = -0.740, p < 0.001), ß-cryptoxanthin (ß = -1.377, p < 0.001), cis-ß carotene (ß = -0.205, p < 0.001), lutein and zeaxanthin (ß = -1.521, p < 0.001), retinyl palmitate (ß = -0.209, p < 0.001), retinyl stearate (ß = -0.034, p = 0.014), total lycopene (ß = -1.20, p = 0.007), trans-ß carotene (ß = -3.185, p < 0.001), trans-lycopene (ß = -0.490, p = 0.039), retinol (ß = -1.366, p < 0.001) and 25-hydroxyvitamin D (ß = -2.483, p < 0.001). Increased 1-hydroxypyrene was inversely correlated with eight serum nutritional biomarkers: α-carotene (ß = -0.601, p = 0.001), ß-cryptoxanthin (ß = -1.071, p = 0.001), cis-ß carotene (ß = -0.170, p = 0.001), lutein and zeaxanthin (ß = -1.074, p < 0.001), retinyl palmitate (ß = -0.214, p = 0.005), retinyl stearate (ß = -0.041, p = 0.043), total lycopene (ß = -1.664, p = 0.011) and retinol (ß = -1.381, p = 0.011). These results demonstrate that PAH exposure is significantly correlated with decreased levels of serum nutritional biomarkers.

Plasma carotenoids and medial temporal lobe atrophy in older adults.

BACKGROUND & AIMS: Carotenoids are vegetable pigments with neuroprotective properties. Clinical studies found efficacy of specific carotenoids on improving brain perfusion and functioning with aging. However, evidence of an effect on neurodegeneration, which may require longer follow-up period to observe, is more limited. Leveraging biomarkers from a large population-based cohort study of older adults, we investigated whether blood carotenoids were associated with atrophy of the medial temporal lobe (a biomarker of neurodegeneration in aging) over 10 years. METHODS: This study included 461 dementia-free participants from the Three-City Bordeaux study (aged ≥65) who had plasma carotenoids measured at baseline and up to three repeated brain imaging exams in the subsequent 10 years. RESULTS: In adjusted linear mixed models, each increase of 1 SD in plasma level of total carotenoids and of ß-carotene was associated with 0.02 cm3 (95% CI, 0.001-0.04; P = 0.04) and 0.02 cm3 (95% CI, 0.01-0.04; P = 0.008) smaller medial temporal lobe volume loss per year, respectively. CONCLUSIONS: Our results based on a unique long-term prospective evaluation of a neuroimaging biomarker suggest a beneficial role of carotenoids for the prevention of age-related neurodegeneration.

Biomarker-based validity of a food frequency questionnaire estimating intake in Brazilian children and adolescents.

This study evaluated the validity of nutrient and food group intakes estimated by an FFQ against biomarkers. A 71-item semiquantitative FFQ was administered to 210 Brazilian children and adolescents aged 9-13 years. Intakes were correlated with biomarkers in plasma and red blood cells. Correlations between nutrients and their biomarkers were presented for animal protein, myristic acid (C14:0), EPA, DHA, ß-carotene, folate, and vitamins B3, B5 and B6. Food groups and biomarkers were correlated as follows: fish products with EPA and DHA; milk and dairy with C14:0, pyridoxal 5'-phosphate and vitamin B12; total vegetables and dark green and orange vegetables with ß-carotene; 5-methyltetrahydrofolate with green vegetables; and flour products with para-aminobenzoylglutamic acid. This FFQ is a valid tool for ranking Brazilian children and adolescents according to their intake of several nutrients and food groups.

Serum retinol, ß-carotene, and α-tocopherol as biomarkers for disease risk and milk production in periparturient dairy cows.

The effectiveness of using serum vitamin concentrations as biomarkers to predict diseases in dairy cows during the periparturient period is not well known. The objective of this study was to evaluate the association between serum ß-carotene, retinol, and α-tocopherol concentrations and periparturient cow diseases in commercial dairies. We measured serum concentrations of these vitamin-active compounds at dry-off and during close-up (approximately 3 wk before calving) and early lactation (approximately 7 d post-calving), and we examined their association with clinical diseases in the first 30 d in milk. Diseases were diagnosed by trained personnel and recorded using database software. Blood samples were taken from 353 cows from 5 different farms over a 3-yr period. Blood samples were analyzed for ß-carotene, retinol, α-tocopherol, and cholesterol. We built separate mixed logistic regression models for each disease outcome: hyperketonuria, lameness, mastitis, uterine diseases (retained placenta or metritis), and an aggregate outcome. For the aggregate outcome, a cow was considered positive if she had one or more of the following: hyperketonuria, lameness, mastitis, uterine disease, pneumonia, milk fever, or displaced abomasum. Concentrations of all 3 fat-soluble vitamins decreased significantly in early lactation relative to the 2 prepartum sampling times. Serum retinol concentrations at close-up and early lactation were negatively associated with odds of developing postpartum hyperketonuria. At early lactation, cows with uterine disease had lower serum retinol concentrations than cows without uterine disease. Similarly, lower serum retinol concentrations were associated with greater odds of having any one disease in the aggregate outcome. First-test 305-d mature-equivalent milk yield was positively correlated with increased serum α-tocopherol and negatively correlated with ß-carotene concentrations. This study demonstrates the potential for serum ß-carotene, retinol, and α-tocopherol to serve as biomarkers for disease risk.

Carotenoid deprivation and beta-carotene's effects on male and female turtle color.

Carotenoid-colored integuments commonly function as sexually selected honest signals because carotenoid pigments can be costly to obtain, ingest, absorb, metabolize or transport before being deposited into the integument. As such, carotenoid pigmentation is often sexually dichromatic, with males being more colorful than females. Sexual dichromatism may also occur in ultraviolet (UV) wavelengths, which is visible to organisms who possess UV-sensitive photoreceptors. The stripes and spots of painted turtles (Chrysemys picta) are carotenoid-based and reflect UV wavelengths. This research describes UV sexual dichromatism in painted turtles and shows how carotenoid deprivation changes spot and stripe color in male and female painted turtles. Adult turtles were fed a diet that was supplemented with carotenoids (i.e., C diet) or deprived of carotenoids (C-). Stripe and spot color were measured with UV-vis spectrometry, and blood was drawn from all turtles before and after the dietary treatment. HPLC analysis revealed five carotenoids (4 xanthophylls and beta-carotene) circulating in turtle blood. C-diet reduced yellow chroma and increased brightness of yellow and red stripes or spots, relative to the C diet, but there was no sexually dimorphic effect of carotenoid deprivation on color, nor did carotenoid deprivation affect UV reflectance. Carotenoid deprivation reduced all circulating carotenoids, but beta-carotene was the only pigment with a significant effect on post-experimental carotenoids, implying that changes in color were due in part to reduction in circulating levels of beta-carotene. Color generation appears to be complex in turtles and have dietary as well as non-dietary components.

Effects of 2,4-thiazolidinedione (TZD) on milk fatty acid profile and serum vitamins in dairy goats challenged with intramammary infusion of Streptococcus uberis.

The study included two experiments. In the first, 24 lactating Saanen dairy goats received low-energy diet without vitamin supplements. Twelve goats received a daily IV injection of 2,4- thiazolidinedione (TZD), others received saline injection. A week later, 6 goats from each treatment were challenged with intramammary infusion (IMI) of saline (CTRL) or Streptococcus uberis. In the second experiment, 12 Saanen lactating dairy goats received supplemental vitamins to reach NRC recommendation level. Six goats in each group were injected with TZD or saline daily, and 14 d later received Streptococcus uberis IMI in the right half of the udder. The hypotheses were (1) TZD does not affect the level of retinol in blood, and (2) the fatty acid profile is affected by the interaction between mammary infection and TZD in dairy goats. In the first experiment blood samples were collected on d -7, -2, 1, 2, 12 and milk samples were collected on d -8, 1, 4, 7, and 12, both relative to IMI. In the second experiment, blood samples were collected on d -15, 0, 1, and 10 relative to IMI. Milk and serum samples were analyzed for retinol, α-tocopherol and fatty acid profile. Serum retinol and ß-carotene concentrations were higher in the second experiment compared to the first. Serum ß-carotene and α-tocopherol were greater in TZD than CTRL and there was a TZD × time interaction in the first experiment. In addition, the TZD × time interaction showed that the milk fatty acid were reduced in C16 : 0 while C18 : 3 n3 while total omega 3 fatty acids were increased, as well as with minor effect on preventing a transient increase in α-tocopherol in milk. Overall, the TZD may affect the lipid-soluble vitamins and fatty acid profile, potentially altering immune responses, during mastitis in dairy goats.

Validity and Reproducibility of a Culture-Specific Food Frequency Questionnaire in Lebanon.

This study aims to assess the validity and reproducibility of a culture-specific semi-quantitative food frequency questionnaire (FFQ) for Lebanese adults. The 94-item FFQ captures intake of traditional Mediterranean dishes and Western food, reflective of current Lebanese nutrition transition. Among 107 participants (18-65 years), the FFQ was administered at baseline (FFQ-1) and one year thereafter (FFQ-2); 2-3 24-h recalls (24-HRs)/season were collected for a total of 8-12 over four seasons. A subset (n = 67) provided a fasting blood sample in the fall. Spearman-correlation coefficients, Bland-Altman plots, joint-classification and (ICC) were calculated. Mean intakes from FFQ-2 were higher than from the total 24-HRs. Correlations for diet from FFQ-2 and 24-HRs ranged from 0.17 for α-carotene to 0.65 for energy. Joint classification in the same/adjacent quartile ranged from 74.8% to 95%. FFQ-2-plasma carotenoid correlations ranged from 0.18 for lutein/zeaxanthin to 0.59 for ß-carotene. Intra-class correlations for FFQ-1 and FFQ-2 ranged from 0.36 for ß-cryptoxanthin to 0.85 for energy. 24-HRs carotenoid intake varied by season; combining season-specific 24-HRs proximal to biospecimen collection to the FFQ-2 improved diet-biochemical correlations. By applying dietary data from two tools with biomarkers taking into consideration seasonal variation, we report a valid, reproducible Lebanese FFQ for use in diet-disease research.

Serum concentration of vitamin A and its relationship with body adiposity, oxidative stress, and cardiovascular risk in women with recommended dietary intake of vitamin A.

INTRODUCTION: Background: evidence indicates a role of vitamin A in the regulation of fat mass influencing obesity and cardiovascular diseases. Material and methods: a cross-sectional study in 200 women, paired by age and by the recommended dietary intake of vitamin A. Subjects were divided into four groups according to body mass index (BMI): 80 eutrophic (E), 40 overweight (OW), 40 class I obesity (OI) and 40 class II obesity (OII). Lipid and glycemic profiles were measured and oxidative stress was evaluated through serum concentrations of uric acid, glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBARS). Results: the cutoff points for deficiency of serum retinol and ß-carotene levels were < 1.05 µmol/L and 40 µg/dL, respectively. For the recommended dietary intake of vitamin A it was 700 µg/day. Retinol and ß-carotene deficiency was found in the E group at 5 % and 15 %, respectively, reaching 77.5 % and 82.5 % in the OII group. Conclusions: a correlation was observed between serum concentrations of retinol and ß-carotene and glycemic, lipid, and markers of oxidative stress profiles in the groups studied. It was observed that OI and OII subjects who had retinol and ß-carotene deficiency presented a risk that was 16 and 20.7 times greater, respectively, of having a diagnosis with DM2 as compared to E subjects with adequate concentrations of vitamin A. Increased demand of vitamin A may be related to increased BMI, body adiposity, and oxidative stress even when a recommended intake of vitamin A is reached.

INTRODUCCIÓN: Introducción: la evidencia indica un papel de la vitamina A en la regulación de la masa grasa que influye en la obesidad y las enfermedades cardiovasculares. Material y métodos: estudio transversal con 200 mujeres emparejadas por edad y por la ingesta dietética de vitamina A recomendada. Se dividieron en cuatro grupos según el índice de masa corporal (IMC): 80 eutróficas (E), 40 con sobrepeso (OW), 40 con obesidad de clase I (OI) y 40 con obesidad de clase II (OII). Se midieron los perfiles lipídicos y glucémicos y se evaluó el estrés oxidativo a través de las concentraciones séricas de ácido úrico, glutatión-peroxidasa (GSH-Px) y sustancias reactivas del ácido tiobarbitúrico (TBARS). Resultados: los puntos de corte para la deficiencia de las concentraciones séricas de retinol y caroteno fueron de 1,05 µmol/L y 40 g/dL, respectivamente. Para la ingesta dietética recomendada de vitamina A fue de 700 g/día. Se encontró deficiencia de retinol y caroteno en el grupo E, del 5 % y 15 %, respectivamente, alcanzando un 77,5 % y 82,5 % en el grupo OII. Conclusiones: se observó correlación entre las concentraciones séricas de retinol y caroteno y los perfiles glucémico, lipídico y de marcadores de perfiles de estrés oxidativo en los grupos estudiados. Se observó que los sujetos con OI y OII que tenían deficiencia de retinol y caroteno presentaban un riesgo 16 y 20,7 veces mayor, respectivamente, de ser diagnosticados de DM2 en comparación con los E con concentraciones adecuadas de vitamina A. El aumento de la demanda de vitamina A puede estar relacionado con el aumento del IMC, la adiposidad corporal y el estrés oxidativo, incluso cuando se alcanza la ingesta recomendada de vitamina A.

Relationship between Serum Antioxidative Vitamin Concentrations and Type 2 Diabetes in Japanese Subjects.

A high intake of green leafy vegetables rich in antioxidative nutrients such as vitamin C and ß-carotene may protect against the risk of type 2 diabetes. Measurement of the circulating nutrient concentrations can indicate the nutrient status more directly, and vitamin C and carotenoids are recognized as good biomarkers for the intake of fruits and vegetables. The aim of this study was to investigate the relationships between serum antioxidative vitamin concentrations and type 2 diabetes in Japanese subjects. The study subjects comprised 506 men and 493 women who first underwent anti-aging health checks at Tokai University Tokyo Hospital. Serum concentration of vitamin (V) A, VC, α-tocoferol, ß-carotene, VB12, folate, ferritin and homocysteine, and fasting plasma glucose and HbA1c were used for analysis. Low levels of ß-carotene and VC were significantly associated with dysglycemia. Diabetic subjects showed significantly decreased ß-carotene and VC levels, and multivariate analyses suggested that low levels of ß-carotene and VC were factors related to diabetes. Low levels of ß-carotene and VC are significantly related to dysglycemia/type 2 diabetes, and encouraging people at a higher risk of diabetes to take more green vegetables may be useful as a dietary intervention to improve the antioxidative vitamin status and dysglycemia.

Effect of Beta-Carotene Supplementation on the Peripheral Blood Leukocyte Population in Japanese Black Calves.

The purpose of this study was to determine the effect of beta-carotene supplementation to Japanese Black calves on the peripheral blood leukocyte population. Twenty-two Japanese Black calves were alternately assigned to two groups. Eleven calves received 20 mg/d of beta-carotene orally from 2 to 8 wk of age (BC group), and the other 11 calves did not receive (control group). The serum beta-carotene concentration in the BC group at 4, 8 and 12 wk of age were significantly higher than those in the control group (p<0.05). The numbers of CD4+ cells in the BC group were significantly higher than those in the control group at 4 wk of age (p<0.05). These results confirmed that beta-carotene supplementation to Japanese Black calves affected the peripheral blood leukocyte population.