Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism.

This review is respectfully dedicated to the memory of Michel Ollivon, Research Director at CNRS (Châtenay-Malabry, France), outstanding physico-chemist specialist of lipid organization, recipient of the Hilditch Memorial Lecture award, who was the initiator of the network RMT LISTRAL. We are also sadly paying tribute to Jean-Luc Vendeuvre, Food Engineer at the French Pork and Pig Institute (IFIP, Maisons-Alfort, France), outstanding expert in meat products who participated actively in RMT LISTRAL and provided unpublished data for figures in the present review, who passed away during review submission. RMT LISTRAL: Mixed Technological Network combining academic and industrial partners, devoted to the enhancement and divulgation of knowledge regarding structured dietary lipids.International audienceOn a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen

Cas particulier des laits de chèvre et de brebis

National audienceSpecific cases of goat and sheep milks Small ruminants show specificities in terms of production of milk, protein and fat contents, and lipolysis levels, which are inherent in breeding systems, the number and size of animals, their genetic heritage, feeding and seasonality. Specific responses to feeding have been noticed especially on the profiles of fatty acids of nutritional interest (CLA, omega 3...). Nevertheless, whatever the answers, milk fat from small ruminants is characterized by significant levels of short-and medium-chain saturated fatty acids, with present nutritional and health benefits, and also different sizes of fat globules. The high polymorphism of the caprine s1 casein, which directly affects the protein content, also impacts the fat content, the size of fat globules and the lipolysis level. With regard to the use of milk from small ruminants, 98 % of the volume is turned into cheeses, most often without standardization of the fat. The fatty acid profiles from milk and cheese are thus similar implying that any improvement on the quality of the milk fat is directly transfered to the cheese. However, the specific technology, including storage, related to the seasonality can contribute to alter the nutritional and sensorial quality of fat (e.g. oxidation). The relationship between the structure of milk fat and its nutritional qualities is complex and constitute one of the most important current research thematic, especially when one takes into account the matrix effects on the bioavailability of the fat.Les petits ruminants présentent des particularités en terme de production de lait, de taux protéiques et butyreux et de niveaux de lipolyse, qui sont inhérentes aux modes de conduite d'élevage, à leur potentiel génétique, à l'alimentation et à la saisonnalité. Des réponses particulières à l'alimentation ont été enregistrées notamment sur les profils d'acides gras d'intérêt nutritionnel (CLA, omega 3...). Néanmoins, quelles que soient ces réponses, la matière grasse des laits de petits ruminants se caractérise par des teneurs importantes en acides gras saturés à courte et moyenne chaîne, présentant des bénéfices nutritionnels et santé et des tailles de globules gras très variables. Le fort polymorphisme de la caséine s1 caprine, qui influe directement sur les taux protéiques, a également un impact sur les taux de matière grasse, la taille des globules gras et les niveaux de lipolyse. Pour ce qui est de l'utilisation du lait de petits ruminants, 98 % de la production est transformé en fromage, la plupart du temps sans standardisation de la matière grasse. Les profils d'acides gras entre lait et fromage sont donc conservés et toute modification qualitative de la matière grasse du lait est directement répercutée sur les fromages. Néanmoins, des spécificités technologiques, de report notamment, liées à la saisonnalité peuvent contribuer à modifier la qualité de la matière grasse (l'oxydation notamment), nutritionnelle et sensorielle. La relation entre la structuration de la matière grasse laitière et ses qualités nutritionnelles est complexe et constitue une des pistes de recherche, en particulier avec la prise en compte des effets matrice sur la biodisponibilité de la matière grasse

Inhibition naturelle de la croissance de S. aureus dans les fromages au lait cru de chèvre

National audienc

Erratum – Organisation structurale et moléculaire des lipides dans les aliments : impacts possibles sur leur digestion et leur assimilation par l’Homme

From the nutrition point of view, lipids are primarily considered as energy suppliers, their dietary intake having to be limited. In fact, lipids are sources of various fatty acids, and dietary recommendations include the required daily intakes in different fatty acids (fatty acid profile). Beyond these quantitative aspects, fatty acids are part of larger molecules, mainly triacylglycerols (TAG), that are organized in supramolecular structures as for example fat crystals and lipid droplets. Recent advances in nutrition research have demonstrated that these structures, and lipid organization in food matrices, influence digestibility and metabolism of fatty acids. Therefore, the members of the technological network Listral propose a synthesis of the knowledge about the influence of molecular and supramolecular structures of lipids on digestion and metabolic fate of dietary fatty acids originating from for the main food industry sectors. Fatty acids are mainly provided in the diet in the form of TAG, or phospholipids (PL) where they are esterified in external (sn-1, sn-3) or internal (sn-2) position of the glycerol backbone. They can also be found as ethyl esters (EE) in specific formulations. These molecular characteristics of the lipid molecules affect their hydrolysis and their absorption rate but also their metabolism in indifferent organs, as assessed in studies often using inter esterified fat sources. The results depend on the types of fatty acids (saturated or polyunsaturated fatty acids) but also on the model used for the studies: in vitro or in vivo studies; animal model, human newborn or adult, either healthy or exhibiting some diseases. Among others, it was found that the crystal form and fat melting point as affected by the fatty acid profiles and the lipid molecular structures directly impact fatty acid absorption kinetics through modifications of lipolytic enzyme activities. However, in these studies, the relative effect of the thermal properties of lipids and the proportion of saturated fatty acids chains in sn-2 position were hardly distinguished. Supramolecular structures, namely type and size of the fat droplets and their interfacial composition, of lipids, either in their native forms or obtained after food processes, also affect the digestibility and absorption of lipids. This aspect is reviewed with specific focus on dairy, marine, meat, oil plant and egg products. The impact of other nutritional components present in these food matrices on the absorption of lipids is also discussed

Circulating sphingolipid profile is modified by exogenous intake of sphingolipids through supplementation with milk polar lipids in postmenopausal women

International audienc

Milk polar lipids reduce cholesterolemia by decreasing cholesterol absorption in humans (P06-041-19)

International audienceObjectives Nutritional strategies can play a major role in the management of cholesterolemia, notably in postmenopausal women at risk of CVD. Interest has recently grown on the potential health benefits of milk polar lipids (MPL). We showed that isolipidic enrichment of the diet with MPL improved several lipid CV risk factors but underlying mechanisms remained unclear. We hypothesized that MPL reduce intestinal cholesterol absorption in humans. Methods We performed a double-blind randomized controlled trial in 58 postmenopausal women with fasting HDL-cholesterol < 1.6 mM. They were subjected to a 4-week dietary intervention with daily consumption of a cream-cheese containing 12 g of milk fat including either 0 g (control, n = 19), 3 g (n = 19) or 5 g (n = 20) of MPL. Before and after each intervention, blood lipids were measured in the whole cohort whereas fecal lipids and coprostanol were analyzed in a subgroup (n = 7–9 per group). A proof-of-concept mechanistic crossover study was also carried out in 4 ileostomized subjects who performed 8h-postprandial tests after consuming 0g-, 3g- or 5g-MPL enriched cheese labelled with 2H-cholesterol tracer. Plasma, chylomicrons and ileal efflux were analyzed. Results Milk fat enriched with 3 to 5 g MPL induced dose-response reductions in serum total cholesterol (up to −6.8% in 5 g group, p < 0.05), LDL-cholesterol (−8.7%, p < 0.05) and HDL/total-cholesterol ratio (p < 0.001), compared to the control that had no effect. Fecal excretion of coprostanol increased after MPL supplementation (p < 0.05, 3g- and 5g-MPL vs control), and the fecal coprostanol/cholesterol ratio was inversely correlated with serum total- and LDL-cholesterol after intervention (r = −0.5, p < 0.05). In ileostomized subjects, postprandial accumulation of 2H-cholesterol in plasma and chylomicrons was reduced after 3 to 5 g MPL consumption (p < 0.05, vs control). Both cholesterol and milk sphingomyelin increased in ileal efflux after MPL enriched cheeses (p < 0.05). Conclusions Present results suggest that milk polar lipids decrease cholesterol absorption in humans through interactions with sphingomyelin and by increasing conversion of cholesterol to coprostanol

Les lipides polaires laitiers diminuent les facteurs lipidiques du risque cardiovasculaire chez des femmes ménopausées : rôle potentiel de l’interaction intestinale sphingomyéline/cholestérol

International audienc

Les lipides polaires laitiers diminuent les facteurs lipidiques du risque cardiovasculaire chez des femmes ménopausées : rôle potentiel de l’interaction intestinale sphingomyéline/cholestérol

International audienc

Milk polar lipids reduce lipid cardiovascular risk factors in overweight postmenopausal women: towards a gut sphingomyelin-cholesterol interplay

Objectives: Nutritional strategies can play a major role in the management of cholesterolemia, notably in postmenopausal women at risk of CVD. Interest has recently grown on the potential health benefitsof milk polar lipids (MPL).We showed that isolipidic enrichment of the diet with MPL improved several lipid CV risk factors but underlying mechanisms remained unclear. We hypothesized that MPL reduceintestinal cholesterol absorption in humans.Methods:We performed a double-blind randomized controlled trial in 58 postmenopausal women with fasting HDL-cholesterol < 1.6 mM.They were subjected to a 4-week dietary intervention with daily consumption of a cream-cheese containing 12 g of milk fat including either 0 g (control, n = 19), 3 g (n = 19) or 5 g (n = 20) of MPL. Before and after each intervention, blood lipids were measured in the whole cohortwhereas fecal lipids and coprostanol were analyzed in a subgroup (n = 7–9 per group). A proof-of-concept mechanistic crossover study was also carried out in 4 ileostomized subjects who performed 8hpostprandial tests after consuming 0g-, 3g- or 5g-MPL enriched cheese labelled with 2H-cholesterol tracer. Plasma, chylomicrons and ilealefflux were analyzed.Results: Milk fat enriched with 3 to 5 g MPL induced doseresponse reductions in serum total cholesterol (up to −6.8% in 5 g group, p < 0.05), LDL-cholesterol (−8.7%, p < 0.05) and HDL/total-cholesterol ratio (p < 0.001), compared to the control that had no effect. Fecal excretion of coprostanol increased after MPL supplementation (p < 0.05, 3g- and 5g-MPL vs control), and the fecal coprostanol/cholesterol ratio was inversely correlated with serum total- and LDL-cholesterol after intervention (r = −0.5, p < 0.05). In ileostomized subjects, postprandial accumulation of 2Hcholesterol in plasma and chylomicrons was reduced after 3 to 5 g MPL consumption (p < 0.05, vs control). Both cholesterol and milk sphingomyelin increased in ileal efflux after MPL enriched cheeses (p < 0.05).Conclusions: Present results suggest that milk polar lipids decrease cholesterol absorption in humans through interactions with sphingomyelin and by increasing conversion of cholesterol to coprostanol.Funding Sources: ANR (French National Research Agency, VALOBAB project, ANR-11-ALID-007–01), PHRC-I (French Clinical Research Program, 14–007), CNIEL (French Dairy Interbranch Organization)