Analysis of microsamples of human faeces: a non-invasive approach to study the bioavailability of fat-soluble bioactive compounds.

INTRODUCTION: Bioavailability is a critical feature in the assessment of the role of micronutrients in human health. Poorly bioavailable micronutrients like carotenoids may reach significant concentrations in the gastrointestinal tract where they may exert biological actions. PURPOSE: We evaluated a simple collection protocol to determine vitamin A, E and carotenoids in microsamples of human faeces as a non-invasive approach for nutritional studies. METHODS: Microsamples of human faeces were collected using a commercially available device, extracted and analysed on two LC systems. Suitability of the protocol was assessed by evaluating several factors including the effect of simulated colonic conditions and two nutritional scenarios with different dietary components, chemical forms, nutritional goals and target groups. RESULTS: The protocol was reproducible and representative of a faeces sample. The major dietary and serum carotenoids, and several "unidentified" compounds (possibly metabolites) could be detected, and cis-/trans-ß-carotene profile reflected dietary intervention. In faeces of neonates, free retinol, retinyl and α-tocopheryl acetate (from infant formula), long-chain fatty acid retinyl esters (from human milk), free γ-tocopherol and α-tocopherol could be detected. CONCLUSION: Our results show that the analysis of vitamin A, E and carotenoids in microsamples of human faeces is a suitable, non-invasive approach that may provide relevant information regarding responsiveness, nutrient stability and metabolism and may help assess adequacy of chemical forms and delivery systems reaching the colon.

Effect of ß-cryptoxanthin plus phytosterols on cardiovascular risk and bone turnover markers in post-menopausal women: a randomized crossover trial.

BACKGROUND AND AIM: Post-menopausal women are at higher risk of cardiovascular disease and bone demineralization. Phytosterols (PS) may be used for hypercholesterolemia in some groups and ß-cryptoxanthin (ß-Cx) displays a unique anabolic effect on bone. Our aim was to assess the changes in cardiovascular and bone turnover markers from the oral intake of ß-Cx and PS in post-menopausal women. METHODS AND RESULTS: A randomized, double-blind, crossover study with ß-Cx (0.75 mg/day) and PS (1.5 g/day), single and combined, was performed in 38 postmenopausal women. Diet was supplemented with 1 × 250 mL milk-based fruit drink/day for 4 weeks with a wash-out period of 4-weeks in between. Serum ß-Cx and PS were determined by UPLC and CG-FID respectively. Outcome variables included markers of bone turnover and cardiovascular risk. Biological effect was assessed by paired t test and generalized estimating equations analysis that included the previous treatment, the order of intervention and the interactions. The intake of beverages containing ß-Cx and PS brought about a significant increase in serum levels of ß-Cx, ß-sitosterol and campesterol. Intervention caused changes in almost all the markers while the order, previous treatment and the interaction did not reach statistical significance. Only the intake of the beverage containing ß-Cx plus PS brought about significant decreases in total cholesterol, c-HDL, c-LDL and bone turnover markers. CONCLUSIONS: ß-Cx improves the cholesterol-lowering effect of PS when supplied simultaneously and this combination may also be beneficial in reducing risk of osteoporosis. CLINICAL TRIAL REGISTRY: ClinicalTrials.gov number NCT01074723.

Determinants of fat-soluble vitamin status in patients aged 65 years and over.

In the elderly, malnutrition is highly prevalent and a major contributor to increased morbidity and mortality. We aimed to evaluate the fat-soluble vitamin status and potential determinants in patients >65 years of age. Serum vitamins A, D and E were determined by liquid chromatography in 166 patients. Gender, age, season, hospitalization, nutritional markers (albumin and cholesterol), acute-phase reactants (ferritin and C-reactive protein) and renal function (creatinine and glomerular filtrate) were assessed as potential determinants. Prevalence of vitamin deficiency was highly variable, ranging from 0 (vitamin E/cholesterol ratio) to 94% (for vitamin D in hospitalized patients). Vitamin status did not differ according to gender, but age, season, hospitalization, a poor nutritional status and impaired renal function, and the presence of acute-phase response significantly affected serum levels of vitamin A, E and D. In conclusion, in subjects >65 years both demographic and clinical factors determined the fat-soluble vitamin status.

Serum levels of 3-epi-25-OH-D3 during hypervitaminosis D in clinical practice.

CONTEXT: Intoxication from vitamin D supplements has been rarely reported, but nowadays, it occurs more frequently. The presence of the C-3 epimer of 25-hydroxyvitamin D(3) (3-epi-25-OH-D(3)) is highly prevalent in adults, although there is little information regarding its in vivo relevance, if any, especially under pathological conditions. OBJECTIVE: Our aim was to assess the presence of the 3-epi-25-OH-D(3) in serum samples displaying 25-OH-D(3) concentrations indicative of hypervitaminosis D. DESIGN, SETTING, PATIENTS, AND MAIN OUTCOME MEASURE: A total of 58 samples displaying a wide range of concentrations of 25-OH-D(3) (>64-439 ng/ml) by ultrafast liquid chromatography were consecutively recruited and reassessed for the presence of 3-epi-25-OH-D(3) using a second chromatographic system. Data from additional biochemical tests performed as part of the patient evaluation were also recorded. RESULTS: Mean relative contribution of 3-epi-25-OH-D(3) was less than 4%, and concentrations ranged from 2-28.6 ng/ml. Serum levels of the C3 epimer, but not the relative contribution, correlate with serum 25-OH-D(3). Overall, in subjects with 25-OH-D(3) concentrations indicative of hypervitaminosis D, the presence of the C-3 epimer and its levels were apparently unrelated to age, serum markers of renal and liver function, acute-phase reactants, and the presence of hypercalcemia. 3-Epi-25-OH-D(3) did not correlate with PTH, but subjects displaying PTH suppression (<14 pg/ml) showed higher concentrations of 3-epi-25-OH-D(3). CONCLUSION: The relative contribution of 3-epi-25-D(3) was not significantly altered during hypervitaminosis D, although the absolute levels reached in serum may be biologically relevant. From a clinical viewpoint, although the small size of the group may affect the lack of relationships, the presence of 3-epi-25-OH-D(3) was apparently unrelated to serum markers of renal and liver function, acute-phase reactants, PTH, and the presence of hypercalcemia.

Intake of alcohol-free red wine modulates antioxidant enzyme activities in a human intervention study.

Wine intake affects the antioxidant enzyme activities that contribute to the overall antioxidant properties of wine. The purpose of this study is to evaluate whether alcohol-free wine has any effect on antioxidant enzymes. The study was a randomized cross-over human intervention. A low phenolic diet (LPD) was designed to prevent interference from polyphenols in other food sources. In the first period, the volunteers ate only this low phenolic diet; in the second, they ate this diet and also drank 300 mL of alcohol-free wine. The enzymes under study were: superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The activities of glutathione reductase, superoxide dismutase and catalase decreased during the LPD period and increased in the LPD+dealcoholized wine period. On the third day of intervention, significant changes were observed in glutathione reductase and superoxide dismutase activity for both intervention periods under study. Catalase activity changed significantly on the seventh day of intervention. Antioxidant enzymes modulated their activity more easily than the endogenous antioxidants, which did not undergo any changes. Our results show for the first time that the increase in the activity of the antioxidant enzymes is not due to the alcohol content in wine but to the polyphenolic composition. Therefore, alcohol-free wine could be an excellent source of antioxidants to protect people suffering from oxidative stress (cancer, diabetes, alzheimer, etc.) who should not consume alcohol.