Influence of Interesterification of a Stearic Acid-Rich Spreadable Fat on Acute Metabolic Risk Factors

Mechanisms of interesterified fat digestibility in a muffin matrix using a dynamic gastric model

Industrially generated trans-fats have been linked with cardiovascular disease (CVD) and have thus been replaced by interesterified (IE) fats, in foods. Interesterification rearranges fatty acids on the glycerol backbone of a triacylglycerol molecule. However, the impact of IE fat on health is unknown. We recently reported differences in lipid absorption kinetics between IE and rapeseed oil (RO). Here, we investigated the mechanisms underpinning IE fat digestion kinetics in the same muffins baked using an IE fat, non-IE fat [with the same fatty acid composition] and rapeseed oil (RO) under simulated conditions. IE and non-IE fats were largely solid in the gastric phase and strongly associated within the muffin matrix, whereas RO formed liquid droplets which separated from the matrix. No significant difference in lipolysis rates was detected between IE and non-IE fats. The lipolysis of the RO fat was slower, due to long-chain PUFAs. Interesterification itself did not affect digestibility, but the strong interaction between the hard fats and the muffin matrix resulted in extensive creaming of the matrix in the stomach, leading to delayed gastric emptying compared to the RO sample. The rate and extent of lipolysis were determined by the amount of fat available and the structure of the fat. This demonstrates the importance of the physical behaviour of the fats during digestion and provides a mechanistic understanding of the overall lipid digestion of IE fats, which relates to their physiological response.

INTERESTERIFIED FAT MATERNAL CONSUMPTION BEFORE CONCEPTION PROGRAMMS MEMORY AND LEARNING OF ADULTHOOD OFFSPRING: how big is this deleterious repercussion?

In recent years, interesterified fat (IF) has largely replaced trans fat in industrialized food. Studies of our research group showed that IF consumption may not be safe for central nervous system (CNS) functions. Our current aim was to evaluate IF maternal consumption before conception on cognitive performance of adult rat offspring. Female Wistar rats were fed with standard chow plus 20% soybean and fish oil mix (control group) or plus 20% IF from weaning until adulthood (before mating), when the diets were replaced by standard chow only. Following the gestation and pups' development, locomotion and memory performance followed by neurotrophin immunocontent and fatty acids (FA) profile in the hippocampus of the adulthood male offspring were quantified. Maternal IF consumption before conception decreased hippocampal palmitoleic acid incorporation, proBDNF and BDNF levels, decreasing both exploratory activity and memory performance in adult offspring. Considering that, the adult male offspring did not consume IF directly, further studies are needed to understand the molecular mechanisms and if the IF maternal preconception consumption could induce the epigenetic changes observed here. Our outcomes reinforce an immediate necessity to monitor and / or question the replacement of trans fat by IF with further studies involving CNS functions.

Interesterified palm oil increases intestinal permeability, promotes bacterial translocation, alters inflammatory parameters and tight-junction protein genic expression in Swiss mice

High-fat diets seem to have a negative influence on the development of obesity and the processes associated with low-grade chronic systemic inflammation. In recent years, partial hydrogenated oil, rich in trans isomers, has been associated with deleterious health effects. It has been replaced by interesterified fat (IF). However, there is no evidence whether IF ingestion can exert adverse effects on the intestinal mucosa. Thus, this study aimed to evaluate the effect of IF on the intestinal mucosa of male Swiss mice fed a normal or high-fat diet, focusing on its effects on intestinal permeability and bacterial translocation and its possible damage to the intestinal epithelium. The animals were divided into 4 groups: Control (C) and Interesterified Control (IC) groups (10 En% lipids from unmodified fat or interesterified fat, respectively) and High Fat (HF) and Interesterified High Fat (IHF) groups (45 En% lipids from unmodified fat or interesterified fat, respectively). Compare to C, the IC, HF, and IHF groups presented flattened epithelium, a shorter villi length and a lower percentage of goblet cells, less mucin 2, an increased oxidative stress and more inflammatory cells, higher IL-1β, IL-17, and IL-23 levels. These groups also presented increased intestinal permeability and gene expression of the protein claudin 2, while JAM-A and claudin 1 gene expression was reduced. IC and IHF increased IL-6 levels while reducing occludin expression. In addition, the IC group also presented a mucosa with lesions of low intensity in the ileum, an increased mucin 5ac, TNF-α levels, and reduced occludin expression in the distal jejunum. Moreover, there was a significant increase in bacterial translocation in the IC group to blood, liver, and lungs, while HF and IHF groups presented bacterial translocation which was restricted to the mesenteric lymph nodes. In summary, our results supported the hypothesis that IF added to a normolipidic diet can be considered harmful or even worse when compared to a HF.

Interesterified palm oil impairs glucose homeostasis and induces deleterious effects in liver of Swiss mice

BACKGROUND

Interesterified fats have largely replaced the partially hydrogenated oils which are the main dietary source of trans fat in industrialized food. This process promotes a random rearrangement of the native fatty acids and the results are different triacylglycerol (TAG) molecules without generating trans isomers. The role of interesterified fats in metabolism remains unclear. We evaluated metabolic parameters, glucose homeostasis and inflammatory markers in mice fed with normocaloric and normolipidic diets or hypercaloric and high-fat diet enriched with interesterified palm oil.

METHODS

Male Swiss mice were randomly divided into four experimental groups and submitted to either normolipidic palm oil diet (PO), normolipidic interesterified palm oil diet (IPO), palm oil high-fat diet (POHF) or interesterified palm oil high-fat diet (IPOHF) during an 8 weeks period.

RESULTS

When compared to the PO group, IPO group presented higher body mass, hyperglycemia, impaired glucose tolerance, evidence of insulin resistance and greater production of glucose in basal state during pyruvate in situ assay. We also observed higher protein content of hepatic PEPCK and increased cytokine mRNA expression in the IPO group when compared to PO. Interestingly, IPO group showed similar parameters to POHF and IPOHF groups.

CONCLUSION

The results indicate that substitution of palm oil for interesterified palm oil even on normocaloric and normolipidic diet could negatively modulate metabolic parameters and glucose homeostasis as well as cytokine gene expression in the liver and white adipose tissue. This data support concerns about the effects of interesterified fats on health and could promote further discussions about the safety of the utilization of this unnatural fat by food industry.

Palmitic Acid Versus Stearic Acid: Effects of Interesterification and Intakes on Cardiometabolic Risk Markers - A Systematic Review

Fats that are rich in palmitic or stearic acids can be interesterified to increase their applicability for the production of certain foods. When compared with palmitic acid, stearic acid lowers low-density lipoprotein (LDL)-cholesterol, which is a well-known risk factor for coronary heart disease (CHD), but its effects on other cardiometabolic risk markers have been studied less extensively. In addition, the positional distribution of these two fatty acids within the triacylglycerol molecule may affect their metabolic effects. The objective was to compare the longer-term and postprandial effects of (interesterified) fats that are rich in either palmitic or stearic acids on cardiometabolic risk markers in humans. Two searches in PubMed/Medline, Embase (OVID) and Cochrane Library were performed; one to identify articles that studied effects of the position of palmitic or stearic acids within the triacylglycerol molecule and one to identify articles that compared side-by-side effects of palmitic acid with those of stearic acid. The interesterification of palmitic or stearic acid-rich fats does not seem to affect fasting serum lipids and (apo) lipoproteins. However, substituting palmitic acid with stearic acid lowers LDL-cholesterol concentrations. Postprandial lipemia is attenuated if the solid fat content of a fat blend at body temperature is increased. How (the interesterification of) palmitic or stearic acid-rich fats affects other cardiometabolic risk markers needs further investigation.

Acute whole apple consumption did not influence postprandial lipaemia: a randomised crossover trial

Whole apples are a source of pectin and polyphenols, both of which show potential to modulate postprandial lipaemia (PPL). The present study aimed to explore the effects of whole apple consumption on PPL, as a risk factor for CVD, in generally healthy but overweight and obese adults. A randomised, crossover acute meal trial was conducted with seventeen women and nine men (mean BMI of 34·1 (sem0·2) kg/m2). Blood samples were collected for 6 h after participants consumed an oral fat tolerance test meal that provided 1 g fat/kg body weight and 1500 mg acetaminophen per meal for estimating gastric emptying, with and without three whole raw Gala apples (approximately 200 g). Plasma TAG (with peak postprandial concentration as the primary outcome), apoB48, chylomicron-rich fraction particle size and fatty acid composition, glucose, insulin and acetaminophen were analysed. Differences between with and without apples were identified by ANCOVA. Apple consumption did not alter postprandial TAG response, chylomicron properties, glucose or acetaminophen (P> 0·05), but did lead to a higher apoB48 peak concentration and exaggerated insulin between 20 and 180 min (P< 0·05). Overall, as a complex food matrix, apples did not modulate postprandial TAG when consumed with a high-fat meal in overweight and obese adults, but did stimulate insulin secretion, potentially contributing to an increased TAG-rich lipoprotein production.

Attenuation of Palm Stearin Emulsion Droplet in Vitro Lipolysis with Crystallinity and Gastric Aggregation

Emulsions with partially crystalline solid (SE) and undercooled-liquid (LE) droplets with equivalent droplet sizes (centering ∼416 nm), surface charges (∼-56 mV), and spherical morphologies were prepared by hot microfluidization based on 10% palm stearin and 0.4% Span 60. Lipid crystallinity attenuated early gastroduodenal lipolysis in vitro ( p < 0.05), both with and without inclusion of a gastric phase ( p < 0.05). Gastric exposure, in particular acidic pH, led to partial coalescence of SE and flocculation and partial crystallization of LE, and it attenuated the rate and extent of lipolysis in both samples. In vitro shear conditions further impacted colloidal stability, particularly for SE, with implications for digestibility. Although lipid crystallinity consistently attenuated early lipolysis, gastric-phase SE partial coalescence had a relatively greater impact on digestibility than did droplet physical state. These findings show that a complex interplay exists among a droplet's physical state, colloidal properties, and digestion conditions, which combine to impact emulsion in vitro lipolysis.

Investigations of in vitro bioaccessibility from interesterified stearic and oleic acid-rich blends

Interesterification was previously found to impact stearic acid absorption in a randomized cross-over study, when human volunteers consumed a 70 : 30 wt% high-oleic sunflower and canola stearin blend (NIE) compared to the same blend which had undergone either chemical (CIE) or enzymatic (EIE) interesterification.

DHA-containing oilseed: a timely solution for the sustainability issues surrounding fish oil sources of the health-benefitting long-chain omega-3 oils

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA.

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

On 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.

The role of dietary fatty acids in the pathology of metabolic syndrome

Dysfunctional lipid metabolism is a key component in the development of metabolic syndrome, a very frequent condition characterized by dyslipidemia, insulin resistance, abdominal obesity and hypertension, which are related to an elevated risk for type 2 diabetes mellitus. The prevalence of metabolic syndrome is strongly associated with the severity of obesity; its physiopathology is related to both genetics and food intake habits, especially the consumption of a high-caloric, high-fat and high-carbohydrate diet. With the progress of scientific knowledge in the field of nutrigenomics, it was possible to elucidate how the majority of dietary fatty acids influence plasma lipid metabolism and also the genes expression involved in lipolysis and lipogenesis within hepatocytes and adipocytes. The aim of this review is to examine the relevant mechanistic aspects of dietary fatty acids related to blood lipids, adipose tissue metabolism, hepatic fat storage and inflammatory process, all of them closely related to the genesis of metabolic syndrome.

Complex links between dietary lipids, endogenous endotoxins and metabolic inflammation

Metabolic diseases such as obesity are characterized by a subclinical inflammatory state that contributes to the development of insulin resistance and atherosclerosis. Recent reports also indicate that (i) there are alterations of the intestinal microbiota in metabolic diseases and (ii) absorption of endogenous endotoxins (namely lipopolysaccharides, LPS) can occur, particularly during the digestion of lipids. The aim of the present review is to highlight recently gained knowledge regarding the links between high fat diets, lipid digestion, intestinal microbiota and metabolic endotoxemia & inflammation.

Triacylglycerol structure and interesterification of palmitic and stearic acid-rich fats: an overview and implications for cardiovascular disease

The position of fatty acids in the TAG molecule (sn-1, sn-2 and sn-3) determines the physical properties of the fat, which affects its absorption, metabolism and distribution into tissues, which may have implications for the risk of CHD. The TAG structure of fats can be manipulated by the process of interesterification, which is of increasing commercial importance, as it can be used to change the physical characteristics of a fat without the generation of trans-fatty acids. Interesterified fats rich in long-chain SFA are commercially important, but few studies have investigated their health effects. Evidence from animal and human infant studies suggests that TAG structure and interesterification affect digestibility, atherogenicity and fasting lipid levels, with fats containing palmitic and stearic acid in the sn-2 position being better digested and considered to be more atherogenic. However, chronic studies in human adults suggest that TAG structure has no effect on digestibility or fasting lipids. The postprandial effects of fats with differing TAG structure are better characterised but the evidence is inconclusive; it is probable that differences in the physical characteristics of fats resulting from interesterification and changes in TAG structure are key determinants of the level of postprandial lipaemia, rather than the position of fatty acids in the TAG. The present review gives an overview of TAG structure and interesterified palmitic and stearic acid-rich fats, their physical properties and their acute and chronic effects in human adults in relation to CHD.