Probiotic from human breast milk, Lactobacillus fermentum, promotes growth in animal model of chronic malnutrition.

BACKGROUND: Chronic undernutrition leads to growth hormone resistance and poor growth in children, which has been shown to be modulated by microbiota. We studied whether Lactobacillus fermentum CECT5716 (Lf CECT5716), isolated from mother's breast milk, could promote juvenile growth through the modulation of lipid absorption in a model of starvation. METHODS: Germ-free (GF) Drosophila melanogaster larvae were inoculated with Lf CECT5716 in conditions of undernutrition with and without infant formula. The impact of Lf CECT5716 on larval growth was assessed 7 days after egg laying (AED) by measuring the larval size and on maturation by measuring the emergence of pupae during 21 days AED. For lipid absorption test, Caco2/TC7 intestinal cells were incubated with Lf CECT5716 and challenged with mixed lipid micelles. RESULTS: The mono-associated larvae with Lf CECT5716 were significantly longer than GF larvae (3.7 vs 2.5 mm; p < 0.0001). The effect was maintained when Lf CECT5716 was added to the infant formula. The maturation time of larvae was accelerated by Lf CECT5716 (12 vs 13.2 days; p = 0.01). Lf CECT5716 did not have significant impact on lipid absorption in Caco2/TC7 cells. CONCLUSIONS: Lf CECT5716 is a growth-promoting strain upon undernutrition in Drosophila, with a maintained effect when added to an infant formula but without effect on lipid absorption in vitro.

Cereal processing influences postprandial glucose metabolism as well as the GI effect.

OBJECTIVE: Technological processes may influence the release of glucose in starch. The aim of this study was to compare the metabolic response and the kinetics of appearance of exogenous glucose from 2 cereal products consumed at breakfast. METHODS: Twenty-five healthy men were submitted to a randomized, open, crossover study that was divided into 2 parts: 12 of the 25 subjects were included in the "isotope part," and the 13 other subjects were included in the "glycemic part." On test days, subjects received biscuits (low glycemic index [GI], high slowly available glucose [SAG]) or extruded cereals (medium GI, low SAG) as part of a breakfast similar in terms of caloric and macronutrient content. The postprandial phase lasted 270 minutes. RESULTS: The rate of appearance (RaE) of exogenous glucose was significantly lower after consumption of biscuits in the first part of the morning (90-150 minutes) than after consumption of extruded cereals (p ≤ 0.05). Conversely, at 210 minutes, it was significantly higher with biscuits (p ≤ 0.01). For the first 2 hours, plasma glucose and insulin were significantly lower after biscuits during the glycemic part. C-peptide plasma concentrations were significantly lower at 90, 120, and 150 minutes after ingestion of the biscuits (p ≤ 0.05). CONCLUSION: The consumption of biscuits with a high content of slowly digestible starch reduces the appearance rate of glucose in the first part of the morning and prolongs this release in the late phase of the morning (210 minutes). Our results also emphasize that modulation of glucose availability at breakfast is an important factor for metabolic control throughout the morning in healthy subjects due to the lowering of blood glucose and insulin excursions.

13C tracer recovery in human stools after digestion of a fat-rich meal labelled with [1,1,1-13C3]tripalmitin and [1,1,1-13C3]triolein.

Lipid metabolism studies focus mainly on oxidation and storage but rarely on faecal elimination, which is needed to assess total lipid distribution during the postprandial period. The purpose of the present work was to set up and validate the analysis of lipid tracers in stools, with an aim of later using this methodology in studies of postprandial lipid tracer metabolism. Eight subjects received a mixture of [1,1,1-(13)C3]tripalmitin and [1,1,1-(13)C3]triolein with a fat-rich meal. The nature and amounts of (13)C lipids excreted in stools during 3 days post-dose were determined by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of fatty acid methyl esters (FAMEs) from total fatty acid (TFA), free fatty acid (FFA) and triacylglycerol (TAG) fractions. The results were expressed as the Cumulative Tracer Recovery of the administered dose (CTR%). The quantities and labelling of FAMEs were higher in FFA than in TAG, indicating that label loss was not due to a lack of digestive lipase activity. The labelling was higher for C16:0 than for C18:1. The CTRs were 7.03 ± 0.77% and 6.87 ± 0.91%, respectively, in TFA and FFA for [1-(13)C] C16:0, while they were 0.60 ± 0.15% and 0.51 ± 0.11% for [1-(13)C] C18:1 (mean ± sem). By studying the kinetics of lipid excretion from subjects, two groups emerged. The first one showed rapid excretion in stool #1, whereas the second showed slower excretion in stools #2-#3. A significant difference was found in the FFA in stool #1 for C16:0 (p < 0.01) and C18:1 (p < 0.05). Individual excretion kinetics showed marked variability. Nevertheless, the CTR over the 3-day study period was substantial and homogenous for all subjects. These results confirm that the assessment of faecal elimination is of great importance when establishing total lipid distribution during the postprandial period and validate the analysis of cumulative tracer loss during 72 h post-tracer ingestion.

Validation of pentaacetylaldononitrile derivative for dual 2H gas chromatography/mass spectrometry and 13C gas chromatography/combustion/isotope ratio mass spectrometry analysis of glucose.

A reference method to accurately define kinetics in response to the ingestion of glucose in terms of total, exogenous and endogenous glucose is to use stable-isotope-labelled compounds such as 2H and 13C glucose followed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis. The use of the usual pentaacetyl (5Ac) derivative generates difficulties in obtaining accurate and reproducible results due to the two chromatographic peaks for the syn and anti isomers, and to the isotopic effect occurring during acetylation. Therefore, the pentaacetylaldononitrile derivative (Aldo) was validated for both isotopes, and compared with the 5Ac derivative. A correction factor including carbon atom dilution (stoichiometric equation) and the kinetic isotopic effect (KIE) was determined. Analytical validation results for the 2H GC/MS and 13C GC/C/IRMS measurements produced acceptable results with both derivatives. When 2H enrichments of plasma samples were < or = 1 mol % excess (MPE), the repeatability (RSD(Aldo Intra assay and Intra day) <0.94%, RSD(5Ac Intra assay and Intra day) <3.29%), accuracy (Aldo <3.4%, 5Ac <29.0%), and stability of the derivatized samples were significantly better when the Aldo derivatives of the plasma samples were used (p < 0.05). When the glucose kinetics were assessed in nine human subjects, after glucose ingestion, the plasma glucose 2H enrichments were identical with both derivatives, whereas the 13C enrichments needed a correction factor to fit together. Due to KIE variation, this correction factor was not constant and had to be calculated for each batch of analyses, to obtain satisfactory results. Mean quantities of exogenous glucose exhibit marked difference (20.9 +/- 1.3g (5Ac) vs. 26.7 +/- 2.5g (Aldo)) when calculated with stoichiometric correction, but fit perfectly when calculated after application of the correction factor (22.1 +/- 1.3g (5Ac) vs. 22.9 +/- 1.9g (Aldo)). Finally, the pentaacetylaldononitrile derivative, used here in GC/C/IRMS for the first time, enables measurement of 2H and 13C enrichments in plasma glucose with a single sample preparation.

Milk Polar Lipids in a High-Fat Diet Can Prevent Body Weight Gain: Modulated Abundance of Gut Bacteria in Relation with Fecal Loss of Specific Fatty Acids.

SCOPE: Enhanced adiposity and metabolic inflammation are major features of obesity associated with altered gut microbiota and intestinal barrier. How these metabolic outcomes can be impacted by milk polar lipids (MPL), naturally containing 25% of sphingomyelin, is investigated in mice fed a mixed high-fat (HF) diet . METHODS AND RESULTS: Male C57Bl/6 mice receive a HF-diet devoid of MPL (21% fat, mainly palm oil, in chow), or supplemented with 1.1% or 1.6% of MPL (HF-MPL1; HF-MPL2) via a total-lipid extract from butterserum concentrate for 8 weeks. HF-MPL2 mice gain less weight versus HF (p < 0.01). Diets do not impact plasma markers of inflammation but in the liver, HF-MPL2 tends to decrease hepatic gene expression of macrophage marker F4/80 versus HF-MPL1 (p = 0.06). Colonic crypt depth is the maximum in HF-MPL2 (p < 0.05). In cecal microbiota, HF-MPL1 increases Bifidobacterium animalis versus HF (p < 0.05). HF-MPL2 decreases Lactobacillus reuteri (p < 0.05), which correlates negatively with the fecal loss of milk sphingomyelin-specific fatty acids (p < 0.05). CONCLUSION: In mice fed a mixed HF diet, MPL can limit HF-induced body weight gain and modulate gut physiology and the abundance in microbiota of bacteria of metabolic interest. This supports further exploration of how residual unabsorbed lipids reaching the colon can impact HF-induced metabolic disorders.

Modulating absorption and postprandial handling of dietary fatty acids by structuring fat in the meal: a randomized crossover clinical trial.

BACKGROUND: Prolonged postprandial hypertriglyceridemia is a potential risk factor for cardiovascular diseases. In the context of obesity, this is associated with a chronic imbalance of lipid partitioning oriented toward storage and not toward ß-oxidation. OBJECTIVE: We tested the hypothesis that the physical structure of fat in a meal can modify the absorption, chylomicron transport, and further metabolic handling of dietary fatty acids. DESIGN: Nine normal-weight and 9 obese subjects were fed 40 g milk fat (+[(13)C]triacylglycerols), either emulsified or nonemulsified, in breakfasts of identical composition. We measured the postprandial triacylglycerol content and size of the chylomicron-rich fraction, plasma kinetics of [(13)C]fatty acids, exogenous lipid oxidation with breath-test/indirect calorimetry, and fecal excretion. RESULTS: The emulsified fat resulted in earlier (>1 h) and sharper chylomicron and [(13)C]fatty acid peaks in plasma than in spread fat in both groups (P < 0.0001). After 2 h, the emulsified fat resulted in greater apolipoprotein B-48 concentrations (9.7 ± 0.7 compared with 7.1 ± 0.9 mg/L; P < 0.05) in the normal-weight subjects than did the spread fat. In the obese subjects, emulsified fat resulted in a 3-fold greater chylomicron size (218 ± 24 nm) compared with the spread fat (P < 0.05). The emulsified fat induced higher dietary fatty acid spillover in plasma and a sharper (13)CO(2) appearance, which provoked increased exogenous lipid oxidation in each group: from 45% to 52% in normal-weight subjects (P < 0.05) and from 40% to 57% in obese subjects (P < 0.01). CONCLUSION: This study supports a new concept of "slow vs fast fat," whereby intestinal absorption can be modulated by structuring dietary fat to modulate postprandial lipemia and lipid ß-oxidation in humans with different BMIs. This trial was registered at clinicaltrials.gov as NCT01249378.

Daily intake of conjugated linoleic acid-enriched yoghurts: effects on energy metabolism and adipose tissue gene expression in healthy subjects.

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. The present study was designed to determine whether 14-week CLA supplementation as triacylglycerols (3.76 g) with a 50 : 50 combination of the two main isomers (35 % cis-9, trans-11 and 35 % trans-10, cis-12) added to flavoured yoghurt-like products was able to alter body composition in healthy subjects and to alter the expression of several key adipose tissue genes (PPAR gamma, lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and uncoupling protein 2 (UCP-2)). Forty-four healthy subjects were randomly assigned to consume daily either a CLA-supplemented yoghurt-like product or a placebo yoghurt for 98 d. There were no significant effects of CLA supplementation on body weight, fat mass or free fat mass. Basal energy expenditure expressed as kg free fat mass increased significantly in the CLA group (123.3 (SEM 2.5) kJ/kg free fat mass per d on day 98 v. 118.7 (SEM 2.3) kJ/kg free fat mass per d on day 0, P = 0.03). PPAR gamma mRNA gene expression increased significantly with CLA supplementation (53 (SEM 20) %, P < 0.01) and a significant reduction in mRNA levels of HSL was observed ( - 42 (SEM 7) %, P = 0.01). The levels of UCP-2 and LPL mRNA were not affected. The present results suggest that a 98 d supplementation diet with a 50 : 50 mixture of the two CLA isomers cis-9, trans-11 and trans-10, cis-12 in a dairy product was unable to alter body composition, although a significant increase in the RMR has been induced. Moreover, changes in mRNA PPAR gamma and HSL in adipose tissue were recorded.