Publications by authors named "Polakof Sergio"

Background & Aim: Dietary shifts replacing animal protein (AP) with plant protein (PP) sources have been associated with lowering cardiometabolic risk (CMR), but underlying mechanisms are poorly characterized. This nutritional intervention aims to characterize the metabolic changes induced by diets containing different proportions of AP and PP sources in males at CMR.

Design: This study is a 4-week, crossover, randomized, controlled-feeding trial in which 19 males with CMR followed two diets providing either 36 % for the control diet (CON-D) or 64 % for the flexitarian diet (FLEX-D) of total protein intake from PP sources.

View Article and Find Full Text PDF

Background: The effects of supplementation with L-arginine (L-arg), the precursor of nitric oxide (NO), on vascular and cardiometabolic health have largely been explored. Whether other mechanisms of the action of L-arg exist remains unknown, as arginine metabolism is complicated.

Objective: We aimed to characterize the effect of low dose L-arg supplementation on overall human metabolism both in a fasting state and in response to an allostatic stress.

View Article and Find Full Text PDF

Nutritional biomarkers of dairy intake can be affected by both food transformation and the metabolic status of the consumer. To assess these effects, this study investigated the serum volatilome of 14 young (YA) and 14 older (OA) adult men undergoing a 3 week restriction of dairy and fermented foods followed by a randomized crossover acute intake of milk and yogurt. 3,5-Dimethyl-octan-2-one was identified as a potential marker of dairy product intake as its response after both milk and yogurt intake was significantly increased during the postprandial phase but significantly decreased in fasting serum samples of the OA group after the restriction phase.

View Article and Find Full Text PDF

Background: Plant proteins (PPs) have been associated with better cardiovascular health than animal proteins (APs) in epidemiological studies. However, the underlying metabolic mechanisms remain mostly unknown.

Objectives: Using a combination of cutting-edge isotopic methods, we aimed to better characterize the differences in protein and energy metabolisms induced by dietary protein sources (PP compared with AP) in a prudent or western dietary context.

View Article and Find Full Text PDF

Purpose Of Review: An increase in the plant-based characteristics of the diet is now recommended for human and planetary health. There is growing evidence that plant protein (PP) intake has beneficial effects on cardiometabolic risk. However, proteins are not consumed isolated and the protein package (lipid species, fiber, vitamins, phytochemicals, etc) may contribute, besides the protein effects per se, to explain the beneficial effects associated with PP-rich diets.

View Article and Find Full Text PDF

Obesity is a major contributor to the silent and progressive development of type 2 diabetes (T2D) whose prevention could be improved if individuals at risk were identified earlier. Our aim is to identify early phenotypes that precede T2D in diet-induced obese minipigs. We fed four groups of minipigs (n = 5-10) either normal-fat or high-fat high-sugar diet during 2, 4, or 6 months.

View Article and Find Full Text PDF

This study explored plasma biomarkers and metabolic pathways underlying feed efficiency measured as residual feed intake (RFI) in Charolais heifers. A total of 48 RFI extreme individuals (High-RFI, n = 24; Low-RFI, n = 24) were selected from a population of 142 heifers for classical plasma metabolite and hormone quantification and plasma metabolomic profiling through untargeted LC-MS. Most efficient heifers (Low-RFI) had greater (P = 0.

View Article and Find Full Text PDF

Impairment of gut function is one of the explanatory mechanisms of health status decline in elderly population. These impairments involve a decline in gut digestive physiology, metabolism and immune status, and associated to that, changes in composition and function of the microbiota it harbors. Continuous deteriorations are generally associated with the development of systemic dysregulations and ultimately pathologies that can worsen the initial health status of individuals.

View Article and Find Full Text PDF

The identification and validation of biomarkers of food intake (BFIs) is a promising approach to develop more objective and complementary tools to the traditional dietary assessment methods. Concerning dairy, their evaluation in terms of intake is not simple, given the variety of existing foods, making it difficult to establish the association between specific dairy products consumption and the effects on human health, which is also dependent on the study population. Here, we aimed at identifying BFI of both milk (M) and yogurt (Y) in 14 healthy young (20-35 years) and 14 older (65-80 years).

View Article and Find Full Text PDF

This review focuses on the added value provided by a research strategy applying metabolomics analyses to assess phenotypic flexibility in response to different nutritional challenge tests in the framework of metabolic clinical studies. We discuss findings related to the Oral Glucose Tolerance Test (OGTT) and to mixed meals with varying fat contents and food matrix complexities. Overall, the use of challenge tests combined with metabolomics revealed subtle metabolic dysregulations exacerbated during the postprandial period when comparing healthy and at cardiometabolic risk subjects.

View Article and Find Full Text PDF

This study evaluates the capacity of a bread enriched with fermentable dietary fibres to modulate the metabolism and nutrients handling between tissues, gut and peripheral, in a context of overfeeding. Net fluxes of glucose, lactate, urea, short chain fatty acids (SCFA), and amino acids were recorded in control and overfed female mini-pigs supplemented or not with fibre-enriched bread. SCFA in fecal water and gene expressions, but not protein levels or metabolic fluxes, were measured in muscle, adipose tissue, and intestine.

View Article and Find Full Text PDF

The dietary shift from animal protein (AP) to plant protein (PP) sources is encouraged for both environmental and health reasons. For instance, PPs are associated with lower cardiovascular and diabetes risks compared with APs, although the underlying mechanisms mostly remain unknown. Metabolomics is a valuable tool for globally and mechanistically characterizing the impact of AP and PP intake, given its unique ability to provide integrated signatures and specific biomarkers of metabolic effects through a comprehensive snapshot of metabolic status.

View Article and Find Full Text PDF

The gut microbiota adapts to age-related changes in host physiology but is also affected by environmental stimuli, like diet. As a source of both pre- and probiotics, dairy and fermented foods modulate the gut microbiota composition, which makes them interesting food groups to use for the investigation of interactions between diet and ageing. Here we present the effects of excluding dairy products and limiting fermented food consumption for 19 days on gut microbiota composition and circulating metabolites of 28 healthy, young (YA) and older (OA) adult men.

View Article and Find Full Text PDF

During ageing, skeletal muscle develops anabolic resistance towards the stimulation of protein synthesis induced by dietary amino acids. The stimulation of muscle protein synthesis after food intake remains insufficient, even with a protein intake recommended for healthy adults. This alteration is one of the mechanisms known to be responsible for the decrease of muscle mass and function during ageing, namely sarcopenia.

View Article and Find Full Text PDF

The postprandial period represents one of the most challenging phenomena in whole-body metabolism, and it can be used as a unique window to evaluate the phenotypic flexibility of an individual in response to a given meal, which can be done by measuring the resilience of the metabolome. However, this exploration of the metabolism has never been applied to the arteriovenous (AV) exploration of organs metabolism. Here, we applied an AV metabolomics strategy to evaluate the postprandial flexibility across the liver and the intestine of mini-pigs subjected to a high fat-high sucrose (HFHS) diet for 2 months.

View Article and Find Full Text PDF

Blood circulation mainly aims at distributing the nutrients required for tissue metabolism and collecting safely the by-products of all tissues to be further metabolized or eliminated. The simultaneous study of arterial (A) and venous (V) specific metabolites therefore has appeared to be a more relevant approach to understand and study the metabolism of a given organ. We propose to implement this approach by applying a metabolomics (NMR) strategy on paired AV blood across the intestine and liver on high fat/high sugar (HFHS)-fed minipigs.

View Article and Find Full Text PDF
Article Synopsis
  • Whey proteins alone may not effectively prevent muscle wasting during aging or catabolic states, as they are digested too quickly to support sustained protein synthesis.
  • Recent studies suggest that supplementing with carbohydrates after whey protein may enhance muscle protein synthesis, though this was not confirmed in cases of glucocorticoid treatment or aging.
  • In experiments with minipigs and aged rats, post-meal carbohydrate energy boluses did not prolong the anabolic response in muscle protein synthesis after whey protein intake, indicating potential limitations of this strategy.
View Article and Find Full Text PDF

A dysregulation of nutrient exchange between tissues (gut, liver, muscles, adipose) occurs during overnutrition and could induce obesity and metabolic diseases. We aimed to evaluate how, in overfed mini pigs, nutrients use and partition were regulated in the gut and liver. Net nutrients fluxes were assessed in the fed (PP) and post absorptive (PA) states at 1, 14 and 60 days of adaptation to overfeeding in five adult Yucatan female multicatheterized minipigs.

View Article and Find Full Text PDF

Elevated plasma branched-chain amino acids (BCAA) levels are often observed in obese insulin-resistant (IR) subjects and laboratory animals. A reduced capacity of the adipose tissues (AT) to catabolize BCAA has been proposed as an explanation, but it seems restricted to obesity models of genetically modified or high fat⁻fed rodents. We aimed to determine if plasma BCAA levels were increased in a model of IR without obesity and to explore the underlying mechanisms.

View Article and Find Full Text PDF

Obesity induced by overfeeding ultimately can lead to nonalcoholic fatty liver disease, whereas dietary fiber consumption is known to have a beneficial effect. We aimed to determine if a supplementation of a mix of fibers (inulin, resistant starch and pectin) could limit or alleviate overfeeding-induced metabolic perturbations. Twenty female minipigs were fed with a control diet (C) or an enriched fat/sucrose diet supplemented (O + F) or not (O) with fibers.

View Article and Find Full Text PDF

With aging, skeletal muscle becomes resistant to the anabolic effect of dietary proteins and sarcopenia develops. Animal proteins, which are rich in leucine, are recommended for the elderly, but it is not known whether their replacement by plant proteins would maintain the health and physical independence of this population. Aged rats were fed with animal proteins (casein and whey proteins) with different leucine contents and compared to rats fed with diets in which whey was substituted with soy proteins and by increasing the total protein content or not.

View Article and Find Full Text PDF

Although peripheral blood mononuclear cells (PBMCs) are widely used as a valuable tool able to provide biomarkers of health and diseases, little is known about PBMC functional (biochemistry-based) metabolism, particularly following short-term nutritional challenges. In the present study, the metabolic capacity of minipig PBMCs to respond to nutritional challenges was explored at the biochemical and molecular levels. The changes observed in enzyme activities following a control test meal revealed that PBMC metabolism is highly reactive to the arrival of nutrients and hormones in the circulation.

View Article and Find Full Text PDF

Little is still known about brain protein synthesis. In order to increase our knowledge of it, we aimed to modulate brain protein synthesis rates through aging, variations in nutritional state (fed state vs. fasted state), high sucrose diet and micronutrient supplementation.

View Article and Find Full Text PDF

High-sugar intake and senescence share common deleterious effects, in particular in liver, but combination of these two factors was little studied. Our aims were to examine the effect of a high-sucrose diet in liver of old rats and also the potential benefices of a polyphenol/micronutrient supplementation. Four groups of 22-month-old male rats fed during 5 months with a diet containing either 13 or 62% sucrose, supplemented or not with rutin, vitamin E, A, D, selenium, and zinc were compared.

View Article and Find Full Text PDF

Objectives: High-fat high-sucrose diet (HFHS) overfeeding is one of the main factors responsible for the increased prevalence of metabolic disorders. Elevated levels of branched-chain amino acids (BCAAs) have been associated with metabolic dysfunctions, including insulin resistance (IR). The aim of this study was to elucidate whether elevated BCAA levels are the cause or the consequence of IR and to determine the mechanisms and tissues involved in such a phenotype.

View Article and Find Full Text PDF