alpha-carotene and retinol-palmitate

Topics: Adult; Area Under Curve; Biological Availability; Carotenoids; Chylomicrons; Diet; Diterpenes; Dose-Response Relationship, Drug; Female; Humans; Intestinal Absorption; Lutein; Lycopene; Models, Biological; Retinyl Esters; Solubility; Soybean Oil; Tocopherols; Vegetables; Vitamin A; Vitamin K 1; Vitamins; Young Adult

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 (β = -0.529, p < 0.001), β-cryptoxanthin (β = -0.968, p < 0.001), cis-β carotene (β = -0.149, p < 0.001), lutein and zeaxanthin (β = -1.188, p < 0.001), retinyl palmitate (β = -0.145, p < 0.001), retinyl stearate (β = -0.025, p = 0.006), total lycopene (β = -1.074, p < 0.001), trans-β carotene (β = -2.268, p < 0.001), trans-lycopene (β = -0.466, p < 0.003), retinol (β = -0.694, p = 0.004) and 25-hydroxyvitamin D (β = -1.247, p = 0.007). Increased 3-hydroxyfluorene was inversely correlated with eleven serum nutritional biomarkers: α-carotene (β = -0.740, p < 0.001), β-cryptoxanthin (β = -1.377, p < 0.001), cis-β carotene (β = -0.205, p < 0.001), lutein and zeaxanthin (β = -1.521, p < 0.001), retinyl palmitate (β = -0.209, p < 0.001), retinyl stearate (β = -0.034, p = 0.014), total lycopene (β = -1.20, p = 0.007), trans-β carotene (β = -3.185, p < 0.001), trans-lycopene (β = -0.490, p = 0.039), retinol (β = -1.366, p < 0.001) and 25-hydroxyvitamin D (β = -2.483, p < 0.001). Increased 1-hydroxypyrene was inversely correlated with eight serum nutritional biomarkers: α-carotene (β = -0.601, p = 0.001), β-cryptoxanthin (β = -1.071, p = 0.001), cis-β carotene (β = -0.170, p = 0.001), lutein and zeaxanthin (β = -1.074, p < 0.001), retinyl palmitate (β = -0.214, p = 0.005), retinyl stearate (β = -0.041, p = 0.043), total lycopene (β = -1.664, p = 0.011) and retinol (β = -1.381, p = 0.011). These results demonstrate that PAH exposure is significantly correlated with decreased levels of serum nutritional biomarkers.

Topics: Adult; Aged; Aged, 80 and over; beta Carotene; Biomarkers; Carotenoids; Cross-Sectional Studies; Diterpenes; Environmental Exposure; Female; Humans; Lutein; Lycopene; Male; Middle Aged; Nutrition Surveys; Nutritional Status; Polycyclic Aromatic Hydrocarbons; Retinyl Esters; Vitamin A; Zeaxanthins

Topics: Adult; beta Carotene; Biological Availability; Carotenoids; Daucus carota; Diterpenes; Enterocytes; Esterification; Female; Humans; Intestinal Absorption; Male; Meals; Plant Extracts; Postprandial Period; Provitamins; Retinyl Esters; Vitamin A; Young Adult

Enzymatic cleavage of the nonsymmetric provitamin A carotenoid α-carotene results in one molecule of retinal (vitamin A), and one molecule of α-retinal, a biologically inactive analog of true vitamin A. Due to structural similarities, α-retinyl esters and vitamin A esters typically coelute, resulting in the overestimation of vitamin A originating from α-carotene. Herein, we present a set of tools to identify and separate α-retinol products from vitamin A. α-Retinyl palmitate (αRP) standard was synthesized from α-ionone following a Wittig-Horner approach. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method employing a C30 column was then developed to separate the species. Authentic standards of retinyl esters and the synthesized α-RP confirmed respective identities, while other α-retinyl esters (i.e. myristate, linoleate, oleate, and stearate) were evidenced by their pseudomolecular ions observed in electrospray ionization (ESI) mode, fragmentation, and elution order. For quantitation, an atmospheric pressure chemical ionization (APCI) source operated in positive ion mode was used, and retinol, the predominant in-source parent ion was selected and fragmented. The application of this method to a chylomicron-rich fraction of human plasma is demonstrated. This method can be used to better determine the quantity of vitamin A derived from foods containing α-carotene.

Topics: Carotenoids; Chromatography, High Pressure Liquid; Diterpenes; Esters; Humans; Retinyl Esters; Stereoisomerism; Tandem Mass Spectrometry; Vitamin A

The vitamin A (VA) value of carotenoids from fruits and vegetables is affected by many factors. This study determined the VA value of alpha-carotene isolated from carrots compared with beta-carotene and retinyl acetate supplements fed to Mongolian gerbils (Meriones unguiculatus). Gerbils (n = 38) were fed a VA-free diet for 4 wk. At baseline, 6 gerbils were killed to determine liver VA. Gerbils were divided into 3 treatment groups (n = 9/group) and given 35, 35, or 17.5 nmol retinyl acetate, alpha-carotene or beta-carotene, respectively, in 2 divided doses 5 h apart each day. The remaining 5 gerbils received oil vehicle. Gerbils were killed after 3 wk of supplementation. Serum samples and livers were collected and analyzed for VA. Liver extracts were subsequently saponified to quantify alpha-retinol. Serum retinol concentrations did not differ among the groups. Liver retinyl palmitate concentrations were significantly higher in the retinyl acetate treatment group (0.198 +/- 0.051 micromol/g; P < 0.05) than in all other groups. The alpha- and beta-carotene treatments resulted in similar retinyl palmitate concentrations, i.e., 0.110 +/- 0.026 and 0.109 +/- 0.051 micromol/g, respectively, which did not differ from the concentrations in gerbils killed at baseline (0.123 +/- 0.024 micromol/g). The oil group had significantly less retinyl palmitate (0.061 +/- 0.029 micromol/g; P < 0.05) than all other groups. alpha-Retinol was detected in livers of the alpha-carotene group (0.062 +/- 0.013 micromol/g). Thus, twice the amount of purified alpha-carotene maintained VA status as well as beta-carotene in VA-depleted gerbils. Conversion factors were approximately 5.5 microg alpha-carotene or approximately 2.8 mug beta-carotene to 1 microg retinol.

Topics: Animals; beta Carotene; Carotenoids; Daucus carota; Diet; Diterpenes; Gerbillinae; Kinetics; Liver; Male; Nutritional Status; Retinyl Esters; Vitamin A; Weight Gain

Assay of serum levels of retinol, retinyl palmitate, alpha-carotene, and beta-carotene to assess nutritional status, to trials of retinol and/or beta-carotene to assess nutritional status, to monitor compliance with medication schedules, and to conduct toxicity surveillance. The optimal assay method for clinical trial use represents a balance between analytical power and speed/simplicity. Three such methods were evaluated by means of shared samples between two laboratories. Each method required less than 15 minutes per assay and detected all of the analytes of interest. Careful evaluation of calibration materials and procedures permitted different laboratories using different methods to produce results with an interlaboratory variability smaller than the within-laboratory variability for each separate method. Typical precisions for the analytes in serum samples are: retinol, 0.06 relative standard deviation (RSD; standard deviation divided by mean value); retinyl palmitate, 0.08 RSD; alpha-carotene, 0.15 RSD; and beta-carotene, 0.11 RSD. Application of these methods to several hundred samples indicated that retinyl palmitate and beta-carotene levels were indicative of administered retinol and beta-carotene, whereas retinol itself was not. Population variability in pretreatment serum levels of these micronutrients expressed as RSD (retinol, 0.24; alpha-carotene, 1.11; and beta-carotene, 0.98) far exceeded the analytical imprecision in these determinations, confirming that the present assays could meet the needs of current clinical intervention trials.

Topics: beta Carotene; Carotenoids; Chromatography, High Pressure Liquid; Diterpenes; Humans; Individuality; Neoplasms; Retinyl Esters; Vitamin A