Comentarios sobre «Hipercarotinemia tras cirugía bariátrica» / Comments on «Hipercarotinemia after bariatric surgery»

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Iridophores and not carotenoids account for chromatic variation of carotenoid-based coloration in common lizards (Lacerta vivipara).

Abstract Carotenoids typically need reflective background components to shine. Such components, iridophores, leucophores, and keratin- and collagen-derived structures, are generally assumed to show no or little environmental variability. Here, we investigate the origin of environmentally induced variation in the carotenoid-based ventral coloration of male common lizards (Lacerta vivipara) by investigating the effects of dietary carotenoids and corticosterone on both carotenoid- and background-related reflectance. We observed a general negative chromatic change that was prevented by ß-carotene supplementation. However, chromatic changes did not result from changes in carotenoid-related reflectance or skin carotenoid content but from changes in background-related reflectance that may have been mediated by vitamin A1. An in vitro experiment showed that the encountered chromatic changes most likely resulted from changes in iridophore reflectance. Our findings demonstrate that chromatic variation in carotenoid-based ornaments may not exclusively reflect differences in integumentary carotenoid content and, hence, in qualities linked to carotenoid deposition (e.g., foraging ability, immune response, or antioxidant capacity). Moreover, skin carotenoid content and carotenoid-related reflectance were related to male color polymorphism, suggesting that carotenoid-based coloration of male common lizards is a multicomponent signal, with iridophores reflecting environmental conditions and carotenoids reflecting genetically based color morphs.

The antioxidant status response to low-fat and walnut paste-enriched meat differs in volunteers at high cardiovascular Risk carrying different PON-1 polymorphisms.

BACKGROUND: Cardiovascular risk largely depends on diet, antioxidant status, and gene polymorphisms. Low-fat meat (CM) and walnut-enriched meat (WM) products may exert potential beneficial health effects with respect to conventional meat products. OBJECTIVE: To compare the effects of consuming WM vs CM on reduced and oxidized glutathione, lipoperoxides, α- and γ-tocopherol levels, and paraoxonase (PON-1), catalase (CAT), and superoxide dismutase (SOD) activities in 22 volunteers (mean age 54.8 years and body mass index 29.6 kg/m(2)) at high cardiovascular risk carrying different PON-1 192/55 polymorphisms. DESIGN: The study was a 5-week nonblinded, randomized, crossover, controlled trial. RESULTS: In general term, WM vs CM improved the volunteers' antioxidant status, with several result modifications occurring after the WM period. CM consumption increased oxidized glutathione and decreased PON-1 activity (at least p < 0.05). When WM vs CM effects were compared, SOD, CAT, and PON-1 enzyme activities increased (at least p < 0.05) in PON-1 192QQ carriers. γ-tocopherol levels and SOD and PON-1 activities increased in PON-1 192QR+RR carriers besides the significant decrease of lipoperoxide levels. In PON-1 55LM+MM carriers, the intervention increased significantly all the investigated enzyme activities and glutathione levels, whereas PON-1 55LL carriers increased their PON-1 activities. CONCLUSIONS: WM consumption should be preferred to CM. The intake of WM vs CM increased PON-1 but the effect upon other antioxidant enzymes and substrates varied depending on the individual's PON-1 polymorphism. PON-1 192QR+RR carriers appear the targets for WM consumption as they increased enzyme activities and γ-tocopherol levels and decreased lipoperoxides.

Bioavailability of ß-cryptoxanthin in the presence of phytosterols: in vitro and in vivo studies.

Bioactive compounds are used in the design and development of new food products with potential health benefits, although little is known regarding their bioavailability and interactions. This study assessed the stability, in vitro bioaccessibility, and human bioavailability of ß-cryptoxanthin from ß-cryptoxanthin-rich drinks with and without added phytosterols developed for this purpose. The developed drinks showed no difference in the content of ß-cryptoxanthin, and they were stable over 6 months. In vitro, hydrolysis of ß-cryptoxanthin esters and the amount of free ß-cryptoxanthin at duodenal and micellar phases were similar regardless of the presence of phytosterols. In the human study, the daily intake provoked significant increments of ß-cryptoxanthin in serum regardless of the type of the drink. In conclusion, in vitro and in vivo human studies have shown that the bioavailability of ß-cryptoxanthin is not significantly affected by the presence of phytosterols when they are simultaneously supplied in a drink.

Depletion of serum carotenoid and other fat-soluble vitamin concentrations following obesity surgery.

BACKGROUND: Obesity constitutes a growing health problem, and surgical treatment of severe obesity is increasingly used. Nutrient deficiencies are common following bariatric surgery and the evidence indicates a progressive increase in the incidence and severity of the deficiency of certain vitamins and related clinical conditions. Because of the potential role of carotenoids in disease prevention, our aim was to assess the carotenoid status in candidates for obesity surgery and the time-course changes following two bariatric procedures. METHODS: Seventy-five candidates for bariatric surgery (17 men, 58 women; age 43 ± 10 years) and a total of 362 serum samples after obesity surgery (i.e., Roux-en-Y gastric bypass (n = 187) and biliopancreatic diversion (n = 175)) were consecutively collected and assessed. Retinol, α- and γ-tocopherol, 25-OH-vitamin D3, lutein, zeaxanthin, α- and ß-cryptoxanthin, lycopene (trans and cis), α- and ß-carotene (trans and cis) were analyzed by high-performance liquid chromatography. RESULTS: Mean serum levels of carotenoids in candidates for obesity surgery were within the reference values reported in controls and seasonal variations were present in several analytes. After surgery, and regardless of the type of intervention, all serum carotenoids dropped following first-order kinetics. Cis/trans ratio of lycopene and ß-carotene did not change after surgery, over the time or between surgical procedures. On a long-term, serum carotenoids were at or below fifth percentile of reference groups. CONCLUSIONS: The chronic low levels of carotenoids in these patients compromise their availability to tissues, constituting an additional risk factor for other clinical conditions. Dietary advice on carotenoid-rich, fortified foods or supplements should be also evaluated in these patients.

Lutein bioavailability from lutein ester-fortified fermented milk: in vivo and in vitro study.

We assessed the bioavailability of lutein from lutein-fortified fermented milk using in vivo and in vitro approaches. Twenty-four volunteers were randomized to take lutein-fortified fermented milk at two levels of fortification. Single-dose bioavailability study (2x100 ml, ca. 8 or 16 mg of lutein) was performed using a three-point approach (baseline, 3.5 and 6.5 h). Multiple-dose study consisted of consuming one serving/day (ca. 4 or 8 mg/100 ml) for 14 days. Blood samples for biochemical, hematological and lutein analysis were drawn at baseline, Day 7 and Day 14. In vitro bioaccessibility was assessed by a static gastrointestinal digestion model. Lutein content, in vitro ester hydrolysis and micellarization, and lutein concentrations achieved in serum were analyzed by HPLC. In vivo, post-prandial response was higher using the high content fermented milk, but the percentage of absorption was not different according to the dose consumed. Net increments at Day 7 and Day 14 were significantly higher on consuming the high-dose milk as well. In vitro, lutein ester hydrolysis was incomplete regardless of the amount initially present. Free lutein released was higher using the high-dose fermented milk, but the percentage of hydrolysis was similar at both levels of fortification. In the micellar phase, the percentage of free and total lutein was not different according to the dose. Our results support the suitability of the fermented milk as a carrier of lutein esters and an in vivo dose-dependent effect upon regular consumption and suggest the usefulness of in vitro models to provide relevant information to predict in vivo responses.

Suitability of 3-point versus 7-point postprandial retinyl palmitate AUC in human bioavailability studies.

BACKGROUND: Bioavailability is a critical feature in the assessment of the role of micronutrients in human health. Although postprandial behaviour does not predict long-term responses and acute responses, it is accepted that the study of triglyceride-rich lipoprotein fractions reflects newly absorbed lipids from recent meals. AIM: To assess the predictive value of a 3-point versus 7-point post-prandial response (area under the curve) in nutrient bioavailability studies in humans. METHODS: We used results from a human bioavailability study (n = 19) that consisted of a single-dose pharmacokinetic assay involving three types of commercially available vitamin A and E fortified milk. RESULTS: Correlation coefficients between 3-point AUC (AUCp, predictive) versus 7-point AUC (AUCc, conventional) ranged between r = 0.81 (P < 0.001) for vitamin A-fortified skim milk and r = 0.95 (P < 0.001) for whole milk. Bland-Altman representations showed a good agreement between the two methods with 95% of the differences within the concordance limits. More than 90% of the subjects were correctly classified in the same or adjacent quartiles and he calculated relative absorption of vitamin A from the foods was, on average, <5% lower using the AUCp compared to that estimated using AUCc. CONCLUSION: The use of the 3-point approach may be a reliable alternative to assess the relative postprandial lipid response in human bioavailability studies. Nevertheless, since this approach has been studied considering one nutrient (i.e. preformed vitamin A) and one type of food (i.e. milk), its applicability to other nutrients and foods should be tested.

Bioavailability of vitamins A and E from whole and vitamin-fortified milks in control subjects.

BACKGROUND: Dairy products fortified with vitamins and minerals represent a growing market that is of interest to those sectors of the population with unbalanced diets and increased needs. However, there is little information on the bioavailability of micronutrients in milk products at dietary intake levels. AIM OF THE STUDY: To evaluate the bioavailability of vitamins A and E in whole milk and fortified whole and skimmed milk in control subjects. METHODS: A single-dose bioavailability study was performed using three commercially available milks (unfortified whole milk and whole and skimmed milk fortified with vitamins A and E). Nineteen volunteers (10 women and 9 men) ingested 430 ml of each milk on different days. The contents of retinol and alpha-tocopherol provided in the milks and the retinyl esters and alpha-tocopherol in triglyceride-rich lipoprotein fractions (TRL) from plasma collected for 6.5 h postprandially were assayed using a quality-controlled HPLC method. The relative absorption of vitamins A and E from milks was calculated on the basis of area under the curve (AUC) versus time curve estimations, adjusted for plasma volume and expressed as percentage of the amount of nutrient provided. RESULTS: The total amounts of retinol and alpha-tocopherol provided ranged between 0.48 and 4.15 micromol and 0.41 and 32.49 micromol, respectively. The AUC value of retinyl palmitate in TRL was higher for fortified whole milk than for the other two milks (unfortified whole and fortified skimmed milk). The percent relative absorption of vitamin A did not differ among the three types of milk. The AUC for alpha-tocopherol was no different after the ingestion of any of these milks. CONCLUSION: The mean percentage of retinol absorption was apparently similar for the three types of milk, regardless of the amount of fat ingested with each type of milk and the vitamin A provided.