Determination of Vitamin A Total Body Stores in Children from Dried Serum Spots: Application in a Low- and Middle-Income Country Community Setting.

BACKGROUND: The retinol isotope dilution (RID) method has been used to evaluate vitamin A (VA) status in healthy adults and children in low- and middle-income countries (LMIC) and to assess the efficacy of various VA interventions. OBJECTIVE: The study was designed to examine whether dried serum spots (DSS) can be applied to RID when conducting VA total body store (TBS) assessments in community settings. METHODS: Four days after an oral dose of 0.4 mg [13C10]retinyl acetate was administered to Filipino children (12-18 mo), a single blood draw was divided to isolate both serum and plasma. Serum (40 µL) was spotted and dried on Whatman 903 cards and shipped at ambient temperature whereas liquid plasma (LP) was frozen at -80°C and shipped on dry ice. The VA tracer to tracee ratio from DSS and LP was quantified by LC-MS/MS. Comparisons between DSS and LP paired samples (n = 72) were made for [13C10]retinol specific activity (SAp) by Pearson's correlation and for VA TBS by Bland-Altman analysis. RESULTS: The sum of 3 coextracted DSS were required to consistently detect [13C10]retinol above the LC-MS/MS limit of quantitation (LOQ). [13C10]retinol SAp from DSS was highly correlated with SAp from LP (r = 0.945; P < 0.01). A comparison of methods for TBS determination using Bland-Altman analysis indicated agreement with an intraindividual difference of 24.7 µmol (4.6%). Mean total liver reserve (TLR) values from DSS and LP were 1.7 µmol/g (± 0.6 SD) and 1.6 µmol/g (± 0.6 SD), respectively. CONCLUSIONS: VA TBS can be determined from DSS thereby reducing the logistics and cost of maintaining a cold chain by shipping samples at ambient temperature and, thus, making the RID technique more feasible in LMIC community settings. This trial was registered at https://clinicaltrials.gov as NCT03030339.

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.

Vitamin A and D Absorption in Adults with Metabolic Syndrome versus Healthy Controls: A Pilot Study Utilizing Targeted and Untargeted LC-MS Lipidomics.

SCOPE: Persons with metabolic syndrome (MetS) absorb less vitamin E than healthy controls. It is hypothesized that absorption of fat-soluble vitamins (FSV) A and D2 would also decrease with MetS status and that trends would be reflected in lipidomic responses between groups. METHODS AND RESULTS: Following soymilk consumption (501 IU vitamin A, 119 IU vitamin D2 ), the triglyceride-rich lipoprotein fractions (TRL) from MetS and healthy subjects (n = 10 age- and gender-matched subjects/group) are assessed using LC-MS/MS. Absorption is calculated using area under the time-concentration curves (AUC) from samples collected at 0, 3, and 6 h post-ingestion. MetS subjects have ≈6.4-fold higher median vitamin A AUC (retinyl palmitate) versus healthy controls (P = 0.07). Vitamin D2 AUC is unaffected by MetS status (P = 0.48). Untargeted LC-MS lipidomics reveals six phospholipids and one cholesterol ester with concentrations correlating (r = 0.53-0.68; P < 0.001) with vitamin A concentration. CONCLUSIONS: The vitamin A-phospholipid association suggests increased hydrolysis by PLB, PLRP2, and/or PLA2 IB may be involved in the trend in higher vitamin A bioavailability in MetS subjects. Previously observed differences in circulating levels of these vitamins are likely not due to absorption. Alternate strategies should be investigated to improve FSV status in MetS.