RESUMEN
We investigated the impact of increased alpha-linolenic acid (ALA) dietary levels on its plasma bioavailability and its bioconversion in n-3 long chain poly unsaturated fatty acids during a 60-d kinetics and the oxidative stress potentially associated. Rats were submitted to a normolipidic diet providing 0, 3, 10 and 24% ALA of dietary lipids for 0, 15, 30 and 60 days. The lipid peroxidation and oxidative stress (nitric oxide (NO) contents and catalase (CAT), superoxide dismutase (SOD), gluthation peroxidase (GPx) activities) were studied in the liver and plasma. When the diet was deprived in n-3 PUFAs, ALA, (eicosanoic acid) EPA and docosahexaenoic acid (DHA) levels decreased in all lipid fractions of plasma and in red blood cell (RBC) lipids. The addition of ALA in the diet linearly improves its bioavailability and its bioconversion in EPA (R²=0.98). By providing 10 to 24% ALA in dietary lipids (LA/ALA, 1·6 and 5·5 respectively), ALA and EPA were more broadly packaged in all lipid fractions (triglyceride (TAG), cholesterol ester (CE) and free fatty acids (FFA)) of plasma from 15 to 30 days timeframe. Only 3% ALA was sufficient to promote the maximal bioconversion of ALA in DHA in phospholipid (PL) and TAG fractions. Additionally, the improvement of ALA bioconversion in EPA and DHA did not impact the oxidative stress markers and limiting lipid peroxidation. To conclude, this study demonstrated that in rat, 10% ALA in the lipid diet for 15-30 days promotes its bioavailability and its bioconversion and allowed the greatest levels in plasma and RBCs.
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Ácidos Grasos Omega-3 , Ratas , Animales , Ácido alfa-Linolénico , Disponibilidad Biológica , Ácidos Docosahexaenoicos , Dieta , Estrés Oxidativo , Antioxidantes , Ácido EicosapentaenoicoRESUMEN
The bioavailability of α-linolenic acid (ALA) from flaxseed oil in an emulsified form v. a non-emulsified form was investigated by using two complementary approaches: the first one dealt with the characterisation of the flaxseed oil emulsion in in vitro gastrointestinal-like conditions; the second one compared the intestinal absorption of ALA in rats fed the two forms of the oil. The in vitro study on emulsified flaxseed oil showed that decreasing the pH from 7·3 to 1·5 at the physiological temperature (37°C) induced instantaneous oil globule coalescence. Some phase separation was observed under acidic conditions that vanished after further neutralisation. The lecithin used to stabilise the emulsions inhibited TAG hydrolysis by pancreatic lipase. In contrast, lipid solubilisation by bile salts (after lipase and phospholipase hydrolysis) was favoured by preliminary oil emulsification. The in vivo absorption of ALA in thoracic lymph duct-cannulated rats fed flaxseed oil, emulsified or non-emulsified, was quantified. Oil emulsification significantly favoured the rate and extent of ALA recovery as measured by the maximum ALA concentration in the lymph (Cmax = 14 mg/ml at 3 h in the emulsion group v. 9 mg/ml at 5 h in the oil group; P < 0·05). Likewise, the area under the curve of the kinetics was significantly higher in the emulsion group (48 mg × h/ml for rats fed emulsion v. 26 mg × h/ml for rats fed oil; P < 0·05). On the whole, ALA bioavailability was improved with flaxseed oil ingested in an emulsified state. Data obtained from the in vitro studies helped to partly interpret the physiological results.
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Grasas de la Dieta/farmacocinética , Emulsiones/química , Aceite de Linaza/química , Sistema Linfático/metabolismo , Ácido alfa-Linolénico/farmacocinética , Animales , Área Bajo la Curva , Ácidos y Sales Biliares/metabolismo , Disponibilidad Biológica , Lino/química , Concentración de Iones de Hidrógeno , Masculino , Ratas , Ratas Wistar , Solubilidad , Temperatura , Triglicéridos/metabolismoRESUMEN
The authors wish to make a correction to the published version of their paper [...].
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We thank Bernard and colleagues for their careful reading and interest in our article Effects on Fatty Acid Metabolism of a New Powdered Human Milk Fortifier Containing Medium-Chain Triacylglycerols and Docosahexaenoic Acid in Preterm Infants [...].
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Recien Nacido Prematuro , Leche Humana , Ácido Araquidónico , Ácidos Docosahexaenoicos , Humanos , Lactante , Recién Nacido , NutrientesRESUMEN
Preterm infants require fortification of human milk (HM) with essential fatty acids (FA) to ensure adequate post-natal development. As part of a larger randomized controlled study, we investigated FA metabolism in a subset of 47 clinically stable preterm infants (birth weight ≤1500 g or gestational age ≤32 weeks). Infants were randomized to receive HM supplemented with either a new HM fortifier (nHMF; n = 26) containing 12.5 g medium-chain FA (MCFA), 958 mg linoleic acid (LA), 417 mg α-linolenic acid (ALA), and 157 mg docosahexaenoic acid (DHA) per 100 g of powder (in compliance with the latest guidelines) or a fat-free HMF (cHMF; n = 21). Plasma phospholipid (PL) and triacylglycerol (TAG), and red blood cell phosphatidylcholine (RBC-PC) and phosphatidylethanolamine (RBC-PE) FA profiles were assessed before and after 21 days of feeding. In the nHMF group, significantly increased levels of n-9 monounsaturated fatty acids were observed, formed most likely by elongation and desaturation of dietary saturated fatty acids present in HM. ALA fortification increased ALA assimilation into plasma TAG. Similarly, DHA fortification enriched the DHA content in RBC-PE, which, in this compartment, was not associated with lower arachidonic acid levels as observed in plasma TAG and phospholipids. RBC-PE, a reliable indicator of FA metabolism and accretion, was the most sensitive compartment in this study.
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Ácidos Docosahexaenoicos/sangre , Alimentos Fortificados/análisis , Fórmulas Infantiles/química , Recien Nacido Prematuro/sangre , Metabolismo de los Lípidos , Triglicéridos/sangre , Ácido Araquidónico/sangre , Carbohidratos de la Dieta/administración & dosificación , Grasas de la Dieta/administración & dosificación , Proteínas en la Dieta/administración & dosificación , Ácidos Docosahexaenoicos/administración & dosificación , Método Doble Ciego , Eritrocitos/metabolismo , Ácidos Grasos Esenciales/administración & dosificación , Ácidos Grasos Esenciales/sangre , Ácidos Grasos Monoinsaturados/sangre , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro/crecimiento & desarrollo , Ácido Linoleico/administración & dosificación , Ácido Linoleico/sangre , Masculino , Leche Humana , Fosfatidilcolinas/sangre , Fosfatidiletanolaminas/sangre , Polvos , Triglicéridos/administración & dosificación , Ácido alfa-Linolénico/administración & dosificación , Ácido alfa-Linolénico/sangreRESUMEN
AIMS/HYPOTHESIS: Inflammation and ectopic lipid deposition contribute to obesity-related insulin resistance (IR). Studies have shown that deficiency of the proinflammatory cytokine tumor necrosis factor-α (TNFα) protects against the IR induced by a high-fat diet (HFD). We aimed to evaluate the relationship between HFD-related inflammation and lipid deposition in skeletal muscle and liver. EXPERIMENTAL DESIGN: Wild-type (WT) and TNFα-deficient (TNFα-KO) mice were subjected to an HFD for 12 weeks. A glucose tolerance test was performed to evaluate IR. Inflammatory status was assessed by measuring plasma and tissue transcript levels of cytokines. Lipid intermediate concentrations were measured in plasma, muscle and liver. The expression of genes involved in fatty acid transport, synthesis and oxidation was analyzed in adipose tissue, muscle and liver. RESULTS: HFD induced a higher body weight gain in TNFα-KO mice than in WT mice. The weight of epididymal and abdominal adipose tissues was twofold lower in WT mice than in TNFα-KO mice, whereas liver weight was significantly heavier in WT mice. IR, systemic and adipose tissue inflammation, and plasma nonesterified fatty acid levels were reduced in TNFα-KO mice fed an HFD. TNFα deficiency improved fatty acid metabolism and had a protective effect against lipid deposition, inflammation and fibrosis associated with HFD in liver but had no impact on these markers in muscle. CONCLUSIONS: Our data suggest that in an HFD context, TNFα deficiency reduced hepatic lipid accumulation through two mechanisms: an increase in adipose tissue storage capacity and a decrease in fatty acid uptake and synthesis in the liver.
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Dieta Alta en Grasa/efectos adversos , Inflamación/etiología , Metabolismo de los Lípidos/genética , Hígado/metabolismo , Músculo Esquelético/metabolismo , Factor de Necrosis Tumoral alfa/genética , Tejido Adiposo/metabolismo , Animales , Ceramidas/metabolismo , Citocinas/sangre , Citocinas/metabolismo , Ácidos Grasos no Esterificados/sangre , Regulación Enzimológica de la Expresión Génica , Inflamación/metabolismo , Resistencia a la Insulina/genética , Cirrosis Hepática/genética , Cirrosis Hepática/patología , Masculino , Ratones , Ratones Noqueados , Tamaño de los Órganos/efectos de los fármacos , Tamaño de los Órganos/genéticaRESUMEN
BACKGROUND & AIMS: Age-related inflammation and insulin resistance (IR) have been implicated in the inability of old muscles to properly respond to anabolic stimuli such as amino acids (AA) or insulin. Since fatty acids can modulate inflammation and IR in muscle cells, we investigated the effect of palmitate-enriched diet and oleate-enriched diet on inflammation, IR and muscle protein synthesis (MPS) rate in old rats. METHODS: Twenty-four 25-month-old rats were fed either a control diet (OC), an oleate-enriched diet (HFO) or a palmitate-enriched diet (HFP) for 16 weeks. MPS using labeled amino acids and mTOR activation were assessed after AA and insulin anabolic stimulation to mimic postprandial state. RESULTS: IR and systemic and adipose tissue inflammation (TNFα and IL1ß) were improved in the HFO group. Muscle genes controlling mitochondrial ß-oxidation (PPARs, MCAD and CPT-1b) were up-regulated in the HFO group. AA and insulin-stimulated MPS in the HFO group only, and this stimulation was related to activation of the Akt/mTOR pathway. CONCLUSIONS: The age-related MPS response to anabolic signals was improved in rats fed an oleate-enriched diet. This effect was related to activation of muscle oxidative pathways, lower IR, and a decrease in inflammation.