RESUMEN
SCOPE: Dietary fat composition is an important modulator of vascular function. Non-esterified fatty acids (NEFA) enriched in saturated fatty acids (SFA) are thought to reduce vascular reactivity by attenuating insulin signalling via vasodilator pathways (phosphoinositide 3-kinase (PI3K)/Akt/endothelial nitric oxide synthase (eNOS)) and enhancing signalling via pro-inflammatory pathways. METHODS: To examine the effects of fatty acids on these pathways, human aortic endothelial cells were incubated with single fatty acids, and mixtures of these fatty acids to mimic typical NEFA composition and concentrations achieved in our previous human study. RNA was extracted to determine gene expression using real-time RT-PCR and cell lysates prepared to assess protein phosphorylation by Western blotting. RESULTS: Oleic acid (OA, 100 µM) was shown to down regulate expression of the insulin receptor, PTEN and a PI3K catalytic (p110ß) and regulatory (p85α) subunit compared to palmitic, linoleic and stearic acids (P < 0.04), and promote greater eNOS phosphorylation at Ser1177. Both concentration and composition of the SFA and SFA plus n-3 polyunsaturated fatty acids (PUFA) mixtures had significant effects on genes involved in the PI3K/Akt pathway. Greater up-regulation was found with 800 than 400 µM concentration (respective of concentrations in insulin resistant and normal individuals), whereas greater down-regulation was evident with SFA plus n-3 PUFA than SFA mixture alone. CONCLUSION: Our findings provide novel insights into the modulation of the PI3K/Akt/eNOS pathway by single fatty acids and fatty acid mixtures. In particular, OA appears to promote signalling via this pathway, with further work required to determine the primary molecular site(s) of action.
Asunto(s)
Óxido Nítrico Sintasa de Tipo III , Fosfatidilinositol 3-Quinasa , Células Endoteliales , Ácidos Grasos/metabolismo , Ácidos Grasos/farmacología , Ácidos Grasos no Esterificados/farmacología , Humanos , Insulina/metabolismo , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Fosfatidilinositol 3-Quinasa/metabolismo , Fosfatidilinositol 3-Quinasa/farmacología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
BACKGROUND: A highly soluble iron-casein complex has been developed for food fortification purposes with the aim to provide high iron bioavailability. OBJECTIVE: We aimed to determine the iron bioavailability of the iron-casein complex relative to that of ferrous sulfate (control) when given with whole milk in healthy young women. METHODS: A randomized comparator-controlled trial with a crossover design was conducted using the erythrocyte incorporation dual stable isotope (57Fe, 58Fe) technique. Iron absorption from the iron-casein complex was compared with that from ferrous sulfate in 21 healthy women aged 20-38 y with normal iron status. RESULTS: Fractional iron absorption (geometric mean; -SD, +SD) from the iron-casein complex (3.4%; 1.4%, 5.4%) and from ferrous sulfate (3.9%; 1.7%, 6.1%) were not statistically different (P > 0.05). The relative bioavailability value of the iron-casein complex to ferrous sulfate was determined to be 0.87 (-1 SD, +1 SD: -0.90, +2.64). CONCLUSIONS: The iron-casein complex has iron bioavailability comparable to that of ferrous sulfate in healthy young women. This trial was registered at www.anzctr.org.au as ACTRN12615000690550.
Asunto(s)
Caseínas/metabolismo , Compuestos Ferrosos/metabolismo , Aditivos Alimentarios/metabolismo , Hierro/metabolismo , Leche/metabolismo , Adulto , Animales , Disponibilidad Biológica , Femenino , Alimentos Fortificados/análisis , Humanos , Isótopos de Hierro/metabolismo , Leche/química , Adulto JovenRESUMEN
As the food matrix is a determinant of the rate of fat digestion and absorption, it is important for the modulation of postprandial triglyceridaemia. High postprandial triglyceride levels are associated with an increase in inflammation, oxidative stress, an imbalance in the lipoprotein profile and an increase in the risk of developing chronic diseases. This study was designed to assess the in vitro digestion patterns and the postprandial lipaemic responses to test foods with the same nutrient composition but differing in the form and structure. A liquid, a semi-solid and a solid test food with the same nutrient and energy composition were designed. The digestion profiles of the three foods were assessed using a dynamic in vitro model. The foods were also consumed by healthy young adults who donated blood samples after an overnight fast and again 0.5, 1, 2, 3, 4 and 6 h after consuming each of the test foods and who were also assessed for appetite sensations. The solid food showed phase separation during gastric digestion and a lower release of fatty acids during intestinal digestion than the liquid and semi-solid foods. During the postprandial feeding experiments, the solid food caused a lower increase in serum triglycerides than the liquid food and produced higher fullness and satisfaction. In conclusion, the food form and structure modulated fat release, postprandial triglyceridaemia and appetite sensations independent of the nutrient and energy content. Thus, manipulation of the food structure and form may be used in designing strategies for improving metabolic markers and satiety.
Asunto(s)
Análisis de los Alimentos , Metabolismo de los Lípidos , Periodo Posprandial , Adolescente , Adulto , Apetito , Estudios Cruzados , Digestión , Femenino , Humanos , Lípidos/química , Masculino , Triglicéridos/sangre , Adulto JovenRESUMEN
Our objective was to determine whether the endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism influences vascular response to raised NEFA enriched with saturated fatty acids (SFA) or long-chain (LC) n-3 polyunsaturated fatty acids (PUFA). Subjects were prospectively recruited for genotype (Glu298, n = 30 and Asp298, n = 29; balanced for age and gender) consumed SFA on two occasions, with and without the substitution of 0.07 g fat/kg body weight with LC n-3 PUFA, and with heparin infusion to elevate NEFA. Endothelial function was measured before and after NEFA elevation (240 min), with blood samples taken every 30 min. Flow-mediated dilation (FMD) decreased following SFA alone and increased following SFA+LC n-3 PUFA. There were 2-fold differences in the change in FMD response to the different fat loads between the Asp298 and Glu298 genotypes (P = 0.002) and between genders (P < 0.02). Sodium nitroprusside-induced reactivity, measured by laser Doppler imaging with iontophoresis, was significantly greater with SFA+LC n-3 PUFA in all female subjects (P < 0.001) but not in males. Elevated NEFA influences both endothelial-dependent and endothelial-independent vasodilation during the postprandial phase. Effects of fat composition appear to be genotype and gender dependent, with the greatest difference in vasodilatory response to the two fat loads seen in the Asp298 females.
Asunto(s)
Ácidos Grasos no Esterificados/metabolismo , Ácidos Grasos/administración & dosificación , Aceites de Pescado/farmacología , Óxido Nítrico Sintasa de Tipo III/genética , Polimorfismo de Nucleótido Simple , Vasodilatación/efectos de los fármacos , Adolescente , Adulto , Anciano , Estudios Cruzados , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Ácidos Grasos/química , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Óxido Nítrico Sintasa de Tipo III/metabolismo , Periodo Posprandial , Estudios Prospectivos , Método Simple Ciego , Vasodilatación/genéticaRESUMEN
BACKGROUND: Experimental elevation of nonesterified fatty acids (NEFAs) impairs endothelial function, but the effect of NEFA composition is unknown. OBJECTIVE: The objective was to test the effect of acute elevation of NEFAs enriched with either saturated fatty acids (SFAs) or SFAs with long-chain (LC) n-3 (omega-3) PUFAs on vascular function measured via flow-mediated dilatation (FMD), laser Doppler iontophoresis (LDI), and digital volume pulse (DVP). DESIGN: In 59 subjects (30 men and 29 women), repeated oral fat feeding of either palm stearin (SFA) or palm stearin with DHA-rich fish oil (SFA + LC n-3 PUFA) was performed on 2 separate occasions with continuous heparin infusion to elevate NEFAs for a duration of 60 to 240 min. Vascular function was measured at baseline and at the end of NEFA elevation; venous blood was collected for measurement of lipids and circulating markers of endothelial function. RESULTS: NEFA elevation during consumption of the SFA-rich drinks was associated with a marked impairment of FMD, whereas consumption of SFAs + LC n-3 PUFAs improved FMD response, with a mean (±SEM) difference of 2.06 ± 0.29% (P < 0.001). Positive correlations were found with percentage weight of LC n-3 PUFAs in circulating NEFAs and change in FMD response [Spearman's rho (r(s)) = 0.460, P < 0.001]. LDI measures increased during both treatments (P ≤ 0.026), and there was no change in DVP indexes. CONCLUSIONS: The composition of NEFAs can acutely affect FMD. The beneficial effect of LC n-3 PUFAs on postprandial vascular function warrants further investigation but may be mediated by nitric oxide-independent mechanisms. This trial is registered at clinicaltrials.gov as NCT01351324.
Asunto(s)
Grasas de la Dieta/administración & dosificación , Ácidos Docosahexaenoicos/farmacología , Endotelio Vascular/efectos de los fármacos , Ácidos Grasos no Esterificados/efectos adversos , Ácidos Grasos/efectos adversos , Aceites de Pescado/farmacología , Enfermedades Vasculares/prevención & control , Adulto , Dilatación , Endotelio Vascular/fisiopatología , Ácidos Grasos no Esterificados/sangre , Femenino , Heparina/farmacología , Humanos , Iontoforesis , Masculino , Aceite de Palma , Aceites de Plantas/administración & dosificación , Periodo Posprandial , Estadísticas no Paramétricas , Enfermedades Vasculares/fisiopatologíaRESUMEN
The ability to undertake repeat measurements of flow-mediated dilatation (FMD) within a short time of a previous measurement would be useful to improve accuracy or to repeat a failed initial procedure. Although standard methods report that a minimum of 10 min is required between measurements, there is no published data to support this. Thirty healthy volunteers had five FMD measurements performed within a 2-h period, separated by various time intervals (5, 15 and 30 min). In 19 volunteers, FMD was also performed as soon as the vessel had returned to its baseline diameter. There was no significant difference between any of the FMD measurements or parameters across the visits indicating that repeat measurements may be taken after a minimum of 5 min or as soon as the vessel has returned to its baseline diameter, which in some subjects may be less than 5 min.
Asunto(s)
Arteria Braquial/diagnóstico por imagen , Arteria Braquial/fisiopatología , Dilatación/métodos , Hiperemia/diagnóstico por imagen , Hiperemia/fisiopatología , Ultrasonografía/métodos , Adolescente , Adulto , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de Tiempo , Adulto JovenRESUMEN
OBJECTIVE: To determine the effects of different COCs on endothelial function. BACKGROUND: COCs all contain ethinylestradiol, but different progestins; three of the more common progestins are DSG, LN, and DR. Ethinylestradiol enhances some measures of vascular reactivity, but certain progestins may increase risk of vascular diseases and impair endothelial vasodilation. METHODS: Twenty-nine healthy women taking COCs containing 30 µg ethinylestradiol and 150 µg DSG (Marvelon, n = 10), 150 µg LN (Microgynon, n = 10), or 3 mg DR (Yasmin, n = 9) had their vascular reactivity measured using various techniques during their pill-free week (days 5-7) and the third week of active pills (days 26-28). A reference group (n = 10) underwent the same measurements on two consecutive cycles. RESULTS: FMD and LDI were significantly higher during active-pill visits than pill-free visits in women taking DSG and DR (p < 0.02), but not in women taking LN. There were no differences between the duplicate measures in the reference group. CONCLUSIONS: COCs containing 150 µg DSG or 3 mg DR significantly increase endothelium-dependent vasodilation in both large vessels and peripheral microvasculature. These effects may be due to the progestins exhibiting differential effects on eNOS expression.
Asunto(s)
Androstenos/administración & dosificación , Desogestrel/administración & dosificación , Endotelio Vascular/enzimología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Antagonistas de Receptores de Mineralocorticoides/administración & dosificación , Óxido Nítrico Sintasa de Tipo III/biosíntesis , Vasodilatación/efectos de los fármacos , Adulto , Anticonceptivos Sintéticos Orales , Estrógenos/administración & dosificación , Etinilestradiol/administración & dosificación , Femenino , Humanos , Ciclo Menstrual/efectos de los fármacos , Factores de TiempoRESUMEN
There is emerging evidence to show that high levels of NEFA contribute to endothelial dysfunction and impaired insulin sensitivity. However, the impact of NEFA composition remains unclear. A total of ten healthy men consumed test drinks containing 50 g of palm stearin (rich in SFA) or high-oleic sunflower oil (rich in MUFA) on separate occasions; a third day included no fat as a control. The fats were emulsified into chocolate drinks and given as a bolus (approximately 10 g fat) at baseline followed by smaller amounts (approximately 3 g fat) every 30 min throughout the 6 h study day. An intravenous heparin infusion was initiated 2 h after the bolus, which resulted in a three- to fourfold increase in circulating NEFA level from baseline. Mean arterial stiffness as measured by digital volume pulse was higher during the consumption of SFA (P < 0·001) but not MUFA (P = 0·089) compared with the control. Overall insulin and gastric inhibitory peptide response was greater during the consumption of both fats compared with the control (P < 0·001); there was a second insulin peak in response to MUFA unlike SFA. Consumption of SFA resulted in higher levels of soluble intercellular adhesion molecule-1 (sI-CAM) at 330 min than that of MUFA or control (P ≤ 0·048). There was no effect of the test drinks on glucose, total nitrite, plasminogen activator inhibitor-1 or endothelin-1 concentrations. The present study indicates a potential negative impact of elevated NEFA derived from the consumption of SFA on arterial stiffness and sI-CAM levels. More studies are needed to fully investigate the impact of NEFA composition on risk factors for CVD.
Asunto(s)
Ácidos Grasos Monoinsaturados/farmacología , Ácidos Grasos no Esterificados/farmacología , Ácidos Grasos/farmacología , Triglicéridos/sangre , Adolescente , Adulto , Glucemia , Péptido C/sangre , Polipéptido Inhibidor Gástrico/sangre , Polipéptido Inhibidor Gástrico/metabolismo , Humanos , Insulina/sangre , Masculino , Aceites de Plantas/química , Aceite de Girasol , Adulto JovenRESUMEN
Tests were made to determine whether surface plasmon resonance (SPR) could be used as a technique to study the dissociation properties of bovine casein micelles or of sodium caseinate and the interactions between these protein particles and different polysaccharides. Surfaces of bound micelles or caseinate were made, and the changes in refractive index of these layers were used to define changes in the structures of the chemisorbed material. The technique appears to have some potential for studying details of the dissociation of casein micelles and of the binding of different polysaccharides to caseins.
Asunto(s)
Caseínas/química , Polisacáridos/química , Resonancia por Plasmón de Superficie/métodos , Animales , Bovinos , Cinética , Micelas , Unión ProteicaRESUMEN
The present review comes from the authors of the recent Scientific Advisory Committee on Nutrition (SACN) review Update on Trans Fatty Acids and Health, and focuses on assessing the strength of the evidence for a link between trans-fatty acid (trans-FA) intake and cancer. It evaluates a range of human ecological, case-control and prospective studies with trans-FA exposure assessed using either dietary assessment methods or trans-FA levels in tissues. Relevant animal studies are also presented in order to elucidate potential mechanisms. It concludes that there is weak and inconsistent evidence for a relationship between trans-FA and breast or colorectal cancer. Evidence for an association between trans-FA and prostate cancer is limited, but a recent large case-control study has shown a strong interaction between risk and trans-FA intake for the RNASEL QQ/RQ genotype that is present in about 35 % of the population. This potential association requires further investigation. The single study on non-Hodgkin's lymphoma reported a strong positive association, but only used a single assessment of dietary trans-FA made at the start of the study in 1980, and the significant changes in trans-FA intakes between then and the end of follow-up in 1994 limit the reliability of this observation. There is insufficient evidence to allow any differentiation between the effects of trans-FA from animal or vegetable origin on cancer risk.
Asunto(s)
Grasas de la Dieta/efectos adversos , Neoplasias/inducido químicamente , Ácidos Grasos trans/efectos adversos , Animales , Neoplasias de la Mama/inducido químicamente , Estudios de Casos y Controles , Neoplasias Colorrectales/inducido químicamente , Femenino , Humanos , Masculino , Estudios Prospectivos , Neoplasias de la Próstata/inducido químicamente , RiesgoRESUMEN
Previous research has shown that liposomes prepared from a milk fat globule membrane (MFGM) phospholipid fraction had a significantly higher phase transition temperature, thicker membrane, and lower membrane permeability than liposomes prepared from soya phospholipid material. Subsequent investigations into the relative stability of the two liposome dispersions have found that the MFGM phospholipid liposomes are more stable than their soya counterparts in a range of pH conditions, at a variety of storage and processing temperatures, and in the presence of mono- and divalent cations. These results illustrate some potential advantages in the use of MFGM phospholipids for the manufacture of liposomes for use in food systems.
Asunto(s)
Glycine max/química , Glucolípidos/química , Glicoproteínas/química , Liposomas/síntesis química , Fosfolípidos/química , Estabilidad de Medicamentos , Tecnología de Alimentos , Calor , Concentración de Iones de Hidrógeno , Gotas Lipídicas , Liposomas/química , Microscopía Electrónica de Transmisión , Concentración Osmolar , Factores de TiempoRESUMEN
Liposomes were prepared from a milk fat globule membrane (MFGM) phospholipid fraction and from soy phospholipid material using a high-pressure homogenizer (Microfluidizer). The liposomes were characterized in terms of general structure, phase transition temperature, lamellarity, bilayer thickness, and membrane permeability. The liposomes prepared from the MFGM fraction had a significantly higher phase transition temperature, thicker membrane, and lower membrane permeability. These differences were attributed to different phospholipid compositions of the MFGM and soy phospholipid fractions.