Palmitic acid in the sn-2 position of triacylglycerols acutely influences postprandial lipid metabolism

Fat composition in milk replacers modulates plasma cholesterol of dairy calves

This study evaluated the effect of feeding milk replacers (MR) differing in fat composition on plasma cholesterol of dairy calves. Forty-five individually housed male Holstein calves (2.3 ± 0.82 d; mean ± SD) were blocked by arrival day and age. Within each block, calves were randomly assigned to (1) an MR containing a fat blend with 65% rapeseed and 35% coconut fats (RC), (2) an MR containing 65% palm and 35% coconut fats (PC), and (3) an MR containing 65% lard and 35% dairy cream (LD). All MR were isoenergetic with 30% fat, 25% protein, and 36% lactose (DM). Calves were fed 6.0 L/d from d 1 to 5, 7.0 L/d from d 6 to 9, and 8.0 L/d from d 10 to 35 at 13.5% solids. Water and chopped wheat straw were available ad libitum from arrival onward. Milk, water, and straw intakes were recorded daily. Blood was sampled and BW was measured weekly at 1300 h. Fecal scores were recorded daily after the morning meal. Growth and intakes did not differ among treatments. Plasma total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol concentrations were higher in calves fed RC than PC and LD, and higher in calves fed PC than LD. Additionally, plasma triglyceride was greater in calves fed PC than LD at wk 2 after arrival, while calves fed RC did not differ from other groups. The proportion of abnormal fecal scores was lower in calves fed RC than PC and LD in wk 2. The fat composition in MR significantly influenced lipid metabolism in calves but had no impact on growth.

Effect of structured lipids as dietary supplements on the fatty acid profile, carcass yield, blood chemistry, and abdominal fat deposition of female broilers

An experiment was conducted to evalute the effects of adding palm olein (POL), modified palm olein (high degree of acyl migration palm olein, H-AMD), and lard (total fatty acid saturation degree is similar to palm olein) to the diet of broilers. The study assessed production performance, fatty acid absorption, and abdominal fat deposition. A total of 100 one-week-old female broiler chicks were randomly assigned to three-tiered pens and fed five experimental diets. Enzymatic interesterification of POL causes acyl migration, transforming 1-palmitoyl-2,3-dioleoyl-sn-glycerol (sn-POO) and 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (sn-POP) into 1,3-dioleoyl-2-palmitoyl-sn-glycerol (sn-OPO) and 1,2-dipalmitoyl-3-oleoyl-sn-glycerol (sn-PPO), which increases the saturated fatty acid content at the sn-2 position. Feeding broilers with this modified oil has improved the absorption effect of saturated fatty acids and increased the content of palmitic acid in abdominal tissue by 1.55%-1.69%. The impact on the content and positional distribution of fatty acids deposited in the body is limited. Low-density lipoprotein cholesterol (LDL-C) levels decreased by 34%, while high-density lipoprotein cholesterol (HDL-C) levels increased by 23%, resulting in a lower risk of atherosclerosis. No significant differences have been observed in carcass yield results of the POL and H-AMD groups. Compared with animal-derived oils such as lard which are also rich in saturated fatty acids at the sn-2 position, plant-derived oils such as POL and its modified products have a smaller effect on abdominal fat deposition.

Influence of Emulsion Lipid Droplet Crystallinity on Postprandial Endotoxin Transporters and Atherogenic And Inflammatory Profiles in Healthy Men - A Randomized Double-Blind Crossover Acute Meal Study

SCOPE

Consumption of high-fat meals is associated with increased endotoxemia, inflammation, and atherogenic profiles, with repeated postprandial responses suggested as contributors to chronically elevated risk factors. However, effects of lipid solid versus liquid state specifically have not been investigated.

METHODS AND RESULTS

This exploratory randomized crossover study tests the impact of lipid crystallinity on plasma levels of endotoxin transporters (lipopolysaccharide [LPS] binding protein [LBP] and soluble cluster of differentiation 14 [sCD14]) and select proinflammatory and atherogenic markers (tumor necrosis factor-alpha [TNF-α], C-reactive protein [CRP], interleukin-1-beta [IL-1β], interferon-gamma [IFN-γ], interleukin-6 [IL-6], soluble intercellular adhesion molecule [sICAM], soluble vascular cell adhesion molecule [sVCAM], monocyte chemoattractant protein-1 [MCP-1/CCL2], plasminogen activator inhibitor-1 [PAI-1], and fibrinogen). Fasted healthy men (n = 14, 28 ± 5.5 years, 24.1 ± 2.6 kg m-2) consumed two 50 g palm stearin oil-in-water emulsions tempered to contain either liquid or crystalline lipid droplets at 37 °C on separate occasions with blood sampling at 0, 2-, 4-, and 6-h post-meal. Timepoint data, area under the curve, and peak concentration values are compared. Overall, no treatment effects are seen (p > 0.05). There are significant effects of time, with values decreasing from baseline, for TNF-α, MCP-1/CCL2, PAI-1, and fibrinogen (p < 0.05).

CONCLUSION

Responder analysis pointed to differential treatment effects associated with some participant baseline characteristics but, overall, palm-stearin emulsion droplet crystallinity does not acutely affect plasma endotoxin transporters nor select inflammatory and atherogenic markers.

Health Effects of Various Edible Vegetable Oil: An Umbrella Review

Vegetable oils, derived from diverse sources such as seeds, nuts, and some fruits, play a significant role in dietary health. However, the current evidence on the health effects of different types of vegetable oil consumption remains controversial. This umbrella review aims to synthesize evidence from systematic reviews and meta-analyses to assess the health outcomes associated with various vegetable oils. A comprehensive literature search was performed up to 31 July, 2023 on 12 databases for studies examining the association of different vegetable oils with health outcomes in adults. Data was extracted independently by 2 authors, with evidence strength assessed using the grading of recommendations, assessment, development, and evaluation criteria. A total of 48 studies, including 206 meta-analyses, were included. Moderate to very low certainty evidence showed that monounsaturated and polyunsaturated fatty acids such as canola oil, virgin olive oil, and rice bran oil are beneficial in reducing serum total cholesterol and low-density lipoprotein (LDL) concentrations. Conversely, low to very low certainty evidence suggests that oils high in saturated fats, such as coconut oil and palm oil, increase total cholesterol and LDL concentrations but also raise high-density lipoprotein concentrations. Very low certainty evidence showed the consumption of olive oil, sesame oil, and coconut oil could improve blood sugar control. Low certainty evidence showed olive oil consumption reduced risk of breast, digestive, and other cancers. Moderate to very low certainty evidence suggested that canola oil and sesame oil consumption reduced body weight. The consumption of vegetable oil appears to offer different health benefits, with summary estimates indicating beneficial effects on reducing lipid concentrations, especially with monounsaturated and polyunsaturated rich oils when consumed in recommended amounts. Future research should focus on long-term studies and comprehensive dietary assessments to better understand the health impacts of vegetable oils, providing a basis for informed dietary recommendations. This study was registered at PROSPERO as CRD42021239210.

The Effect of Sn-2 Palmitate on Blood Glucose, Lipids and Body Composition in Middle-Aged and Elderly Adults: A Randomized, Double-Blinded Controlled Trial

Sn-2 palmitate is widely used in infant formula. However, little is known about its effects on metabolism and body composition in middle-aged and elderly adults. In a double-blinded, randomized controlled trial, we enrolled Chinese adults aged 45-75 years with self-reported constipation. Individuals were randomly assigned in a 1:1 ratio to a 1,3-dioleoyl-2-palmitoyl-glycerol (OPO)-enriched oil (66% palmitic acid in the sn-2 position) or a control vegetable oil (24% palmitic acid in the sn-2 position) daily for 24 weeks. Skim milk powder was used as the carrier for both fats. Interviews and body composition were performed at baseline, week 4, week 12 and week 24. A fasting blood draw was taken except at week 4. This study was a secondary analysis and considered exploratory. A total of 111 adults (83 women and 28 men, mean age 64.2 ± 7.0 years) were enrolled, of whom 53 were assigned to the OPO group and 57 to the control group. During the intervention, blood glucose, triglyceride, the triglyceride-glucose index, total cholesterol, low-density lipoprotein cholesterol and remnant cholesterol remained stable, while high-density lipoprotein cholesterol decreased in both groups (p = 0.003). No differences in change were observed between the groups (all p > 0.05). From baseline to week 24, the level of visceral fat increased slightly (p = 0.017), while body weight, total body water, protein, soft lean mass, fat-free mass, skeletal muscle and skeletal muscle mass index (SMI) decreased in two groups (p < 0.01). At weeks 4, 12 and 24, the SMI decreased less in the OPO group than in the control group, with a trend towards significance (p = 0.090). A 24-week daily intake of sn-2-palmitate-enriched oil had no adverse impact on fasting blood glucose, lipids and body composition compared with the control vegetable oil in Chinese adults (funded by Chinese Nutrition Society National Nutrition Science Research Grant, National Key Research and Development Program of China and Wilmar (Shanghai) Biotechnology Research & Development Center Co., Ltd.; ChiCTR1900026480).

Postprandial lipid and vascular responses following consumption of a commercially-relevant interesterified palmitic acid-rich spread in comparison to functionally-equivalent non-interesterified spread and spreadable butter: a randomised controlled trial in healthy adults

Background: Interesterification is an industrial processing technique used widely where hard fats are essential for functionality and consumer acceptability, e.g. margarines and lower fat spreads. Objective: The aim of this study was to compare acute cardiovascular effects of functionally equivalent spreads (similar solid fat content) made with interesterified (IE) or non-IE palm-based fats, or spreadable butter. Methods: A randomised, controlled, 4-armed crossover, double-blind study (25 men, 25 women; 35-75 years; healthy; mean BMI 24.5, SD 3.8), compared effects of mixed nutrient meals containing 50 g fat from functionally equivalent products [IE spread, non-IE spread and spreadable butter (SB), with rapeseed oil (RO) as a reference treatment: with 16.7%, 27.9%, 19.3% and 4% palmitic acid, respectively] on 8 h postprandial changes in plasma triacylglycerol (TAG) and endothelial dysfunction (flow-mediated dilatation; FMD). Circulating reactive oxygen species (estimated using a neutrophil oxidative burst assay), glucose, insulin, NEFA, lipoprotein particle profiles, inflammatory markers (glycoprotein acetylation (Glyc-A) and IL-6), and biomarkers of endotoxemia were measured. Results: Postprandial plasma TAG concentrations after test meals were similar. However following RO versus the 3 spreads, there were significantly higher postprandial apolipoprotein B concentrations, and small HDL and LDL particle concentrations, and lower postprandial extra-large, large, and medium HDL particle concentrations, as well as smaller average HDL and LDL particle sizes. There were no differences following IE compared to the other spreads. Postprandial FMD% did not decrease after high-fat test meals, and there were no differences between treatments. Postprandial serum IL-6 increased similarly after test meals, but RO provoked a greater increase in postprandial concentrations of glycoprotein acetyls (GlycA), as well as 8 h sCD14, an endotoxemia marker. All other postprandial outcomes were not different between treatments. Conclusions: In healthy adults, a commercially-available IE-based spread did not evoke a different postprandial triacylglycerol, lipoprotein subclass, oxidative stress, inflammatory or endotoxemic response to functionally-equivalent, but compositionally-distinct alternative spreads. Clinical trial registry number: NCT03438084 (https://ClinicalTrials.gov).

The triacylglycerol structure and composition of a human milk fat substitute affect the absorption of fatty acids and calcium, lipid metabolism and bile acid metabolism in newly-weaned Sprague-Dawley rats

In this study, the effect of sn-2 palmitic triacylglycerols (sn-2 palmitic TAGs) and the ratio between the two major sn-2 palmitic TAGs (OPL to OPO ratio) in a human milk fat substitute (HMFS) on growth, fatty acid and calcium absorptions, and lipid and bile acid metabolic alterations was investigated in Sprague-Dawley rats. After 4 weeks of high-fat feeding, rats fed with the HMFS containing a sn-2 palmitic acid content of 57.87% and an OPL to OPO ratio of 1.4 showed the lowest TAG accumulation in their livers and hypertrophy of perirenal adipocytes, compared to the groups fed with fats containing a lower sn-2 palmitic acid content or a lower OPL to OPO ratio. Meanwhile, synergistically improved absorption of fatty acids and calcium and increased levels of total bile acids (BAs), especially for the tauro-conjugated BAs (TCDCA, TUDCA, TαMCA, TβMCA, TDCA and TωMCA), were observed in rats by both increasing the sn-2 palmitic acid content and the OPL to OPO ratio in HMFS. In addition, the levels of total BAs and tauro-conjugated BAs were negatively correlated with serum TAG, TC, and LDL-c levels and positively correlated with HDL-c levels according to Spearman's correlation analysis (P < 0.05). Collectively, these findings present new nutritional evidence for the potential effects of the TAG structure and composition of a human milk fat substitute on the growth and lipid and bile acid metabolism of the host in infancy.

Effect of Lard or Plus Soybean Oil on Markers of Liver Function in Healthy Subjects: A Randomized Controlled-Feeding Trial

Humans have consumed lard for thousands of years, but in recent decades, it has become much less popular because it is regarded as saturated fat. Animal studies showed that lard plus soybean oil (blend oil) was more advantageous for liver health than using either oil alone. This study aims to assess the effects of blend oil on liver function markers in healthy subjects. The 345 healthy subjects were randomized into 3 isoenergetic diet groups with different edible oils (30 g/day) (soybean oil, lard, and blend oil (50% lard and 50% soybean oil)) for 12 weeks. The reductions in both aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were greater in the blend oil group than in the two other groups (p = 0.001 and <0.001 for the interaction between diet group and time, respectively). The reductions in AST and ALT in the blend oil group were more significant compared with those in the soybean oil group (p < 0.001) or lard group (p < 0.001). There were no significant differences in the other liver function markers between the groups. Thus, blend oil was beneficial for liver function markers such as AST and ALT compared with soybean oil and lard alone, which might help prevent non-alcoholic fatty liver disease in the healthy population.

PCSK9 Activity Is Potentiated Through HDL Binding

[Figure: see text].

Effects of two consecutive mixed meals high in palmitic acid or stearic acid on 8-h postprandial lipemia and glycemia in healthy-weight and overweight men and postmenopausal women: a randomized controlled trial

Purpose

Palmitic and stearic acids have different effects on fasting serum lipoproteins. However, the effects on postprandial lipemia and glycemia are less clear. Also, the effects of a second meal may differ from those of the first meal. Therefore, we studied the effects of two consecutive mixed meals high in palmitic acid- or stearic acid-rich fat blends on postprandial lipemia and glycemia.

Methods

In a randomized, crossover study, 32 participants followed 4-week diets rich in palmitic or stearic acids, At the end of each dietary period, participants consumed two consecutive meals each containing ± 50 g of the corresponding fat blend.

Results

Postprandial concentrations of triacylglycerol (diet-effect: − 0.18 mmol/L; p = 0.001) and apolipoprotein B48 (diet-effect: − 0.68 mg/L; p = 0.002) were lower after stearic-acid than after palmitic-acid intake. Consequently, total (iAUC_0–8 h) and first meal (iAUC_0–4 h) responses were lower after stearic-acid intake (p ≤ 0.01). Second meal responses (iAUC_4–8 h) were not different. Postprandial changes between the diets in non-esterified fatty acids (NEFA) and C-peptide differed significantly over time (p < 0.001 and p = 0.020 for diet*time effects, respectively), while those for glucose and insulin did not. The dAUC_0–8 h, dAUC_0–4 h, and dAUC_4–8 h for NEFA were larger after stearic-acid intake (p ≤ 0.05). No differences were observed in the iAUCs of C-peptide, glucose, and insulin. However, second meal responses for glucose and insulin (iAUC_4–8 h) tended to be lower after stearic-acid intake (p < 0.10).

Conclusion

Consumption of the stearic acid-rich meals lowered postprandial lipemia as compared with palmitic acid. After the second stearic acid-rich meal, concentrations of C-peptide peaked earlier and those of NEFA decreased more.

Clinical trial registry This trial was registered at clinicaltrials.gov as NCT02835651 on July 18, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02530-2.

Palmitic acid-rich oils with and without interesterification lower postprandial lipemia and increase atherogenic lipoproteins compared with a MUFA-rich oil: A randomized controlled trial

BACKGROUND

Interesterified (IE) fats are widely used in place of trans fats; however, little is known about their metabolism.

OBJECTIVES

To test the impact of a commonly consumed IE compared with a non-IE equivalent fat on in vivo postprandial and in vitro lipid metabolism, compared with a reference oil [rapeseed oil (RO)].

METHODS

A double-blinded, 3-phase crossover, randomized controlled trial was performed in healthy adults (n = 20) aged 45-75 y. Postprandial plasma triacylglycerol and lipoprotein responses (including stable isotope tracing) to a test meal (50 g fat) were evaluated over 8 h. The test fats were IE 80:20 palm stearin/palm kernel fat, an identical non-IE fat, and RO (control). In vitro, mechanisms of digestion were explored using a dynamic gastric model (DGM).

RESULTS

Plasma triacylglycerol 8-h incremental area under the curves were lower following non-IE compared with RO [-1.7 mmol/L⋅h (95% CI: -3.3, -0.0)], but there were no differences between IE and RO or IE and non-IE. LDL particles were smaller following IE and non-IE compared with RO (P = 0.005). Extra extra large, extra large, and large VLDL particle concentrations were higher following IE and non-IE compared with RO at 6-8 h (P < 0.05). No differences in the appearance of [13C]palmitic acid in plasma triacylglycerol were observed between IE and non-IE fats. DGM revealed differences in phase separation of the IE and non-IE meals and delayed release of SFAs compared with RO.

CONCLUSIONS

Interesterification did not modify fat digestion, postprandial lipemia, or lipid metabolism measured by stable isotope and DGM analysis. Despite the lower lipemia following the SFA-rich fats, increased proatherogenic large triacylglycerol-rich lipoprotein remnant and small LDL particles following the SFA-rich fats relative to RO adds a new postprandial dimension to the mechanistic evidence linking SFAs to cardiovascular disease risk.

Fractionated palm oils: emerging roles in the food industry and possible cardiovascular effects

The public health debate about fats and human health has been ongoing for a long time. Specifically, the fat types commonly used in the food industry and the techniques used in extracting them are remarkable in terms of human health. Among these, palm oil, which is mainly associated with cardiovascular disease (CVD), is a vegetable oil type that is widely used in the food industry. Moreover, the fractionation of palm oil has become quite common in the food industry when compared to other culinary oils and fats. Fractional crystallization, which has been recently regarded as an alternative to hydrogenization and interesterification methods, has become more popular in edible oil technology, even though it is an ancient method. The main fractions of palm oil are palm olein and palm stearin. Palm oil fractions, which have some pros and cons, are used in edible oils, such as margarine/shortening, as well as bread and cake-like pastry production. Since the fatty acid composition of palm oil, palm kernel oil, and their fractions is different, each type of oil needs to be evaluated separately with regards to their CVD effects and food preparation applications. However, the effects of the fractionation method and the fractional palm oil produced on health are controversial in the literature. In this review, the use of palm oil produced via the fractional crystallization method in the food industry and its potential CVD effects were evaluated.

Structural-based connectivity and omic phenotype evaluations (SCOPE): a cheminformatics toolbox for investigating lipidomic changes in complex systems

Since its inception, the main goal of the lipidomics field has been to characterize lipid species and their respective biological roles. However, difficulties in both full speciation and biological interpretation have rendered these objectives extremely challenging and as a result, limited our understanding of lipid mechanisms and dysregulation. While mass spectrometry-based advancements have significantly increased the ability to identify lipid species, less progress has been made surrounding biological interpretations. We have therefore developed a Structural-based Connectivity and Omic Phenotype Evaluations (SCOPE) cheminformatics toolbox to aid in these evaluations. SCOPE enables the assessment and visualization of two main lipidomic associations: structure/biological connections and metadata linkages either separately or in tandem. To assess structure and biological relationships, SCOPE utilizes key lipid structural moieties such as head group and fatty acyl composition and links them to their respective biological relationships through hierarchical clustering and grouped heatmaps. Metadata arising from phenotypic and environmental factors such as age and diet is then correlated with the lipid structures and/or biological relationships, utilizing Toxicological Prioritization Index (ToxPi) software. Here, SCOPE is demonstrated for various applications from environmental studies to clinical assessments to showcase new biological connections not previously observed with other techniques.

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.

Interesterified palm olein lowers postprandial glucose-dependent insulinotropic polypeptide response in type 2 diabetes

PURPOSE

We aim to investigate the postprandial effects of palm olein (PO) and chemically interesterified palm olein (IPO) with different proportions of palmitic acid at the sn-2 position using high oleic sunflower oil (HOS) as control fat on concentrations of gut hormones, glucose homeostasis, satiety, lipid and inflammatory parameters in type 2 diabetic (T2D) subjects.

METHODS

Using a randomised double-blind crossover design, 21 (men = 6, women = 15) T2D subjects consumed test meals (3.65 MJ) consisting of a high fat muffin (containing 50 g test fats provided as PO, IPO or HOS) and a milkshake. Postprandial changes in gut hormones, glucose homeostasis, satiety, lipid and inflammatory parameters after meals were analysed. Some of the solid fractions of the IPO were removed and thus the fatty acid composition of the PO and IPO was not entirely equal (PO vs IPO: palmitate 39.8 vs 38.7; oleate 43.6 vs 45.1). PO, IPO and HOS contained 9.7, 38.9 and 0.2 g/100 g total fatty acids of palmitic acid at the sn-2 position, respectively. At 37 °C, IPO contained 4.2% SFC whereas PO and HOS were completely melted.

RESULTS

Our novel observation shows that the incremental area under curve (iAUC) 0-6 h of plasma GIP concentration was on average 16% lower following IPO meal compared with PO and HOS (P < 0.05) meals. Serum C-peptide concentrations exhibited a significant meal × gender interaction (P = 0.009). No differences between test meals were noted for other measurements.

CONCLUSIONS

This study shows no adverse effect of interesterification on hormones associated with glucose homeostasis notably GLP-1 in T2D subjects.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01906359. https://clinicaltrials.gov/ct2/show/NCT01906359.

Effect of Nutrient and Micronutrient Intake on Chylomicron Production and Postprandial Lipemia

Postprandial lipemia, which is one of the main characteristics of the atherogenic dyslipidemia with fasting plasma hypertriglyceridemia, low high-density lipoprotein cholesterol and an increase of small and dense low-density lipoproteins is now considered a causal risk factor for atherosclerotic cardiovascular disease and all-cause mortality. Postprandial lipemia, which is mainly related to the increase in chylomicron production, is frequently elevated in individuals at high cardiovascular risk such as obese or overweight patients, type 2 diabetic patients and subjects with a metabolic syndrome who share an insulin resistant state. It is now well known that chylomicron production and thus postprandial lipemia is highly regulated by many factors such as endogenous factors: circulating factors such as hormones or free fatty acids, genetic variants, circadian rhythms, or exogenous factors: food components, dietary supplements and prescription drugs. In this review, we focused on the effect of nutrients, micronutrients and phytochemicals but also on food structure on chylomicron production and postprandial lipemia.

A comparative study of the effects of palm olein, cocoa butter and extra virgin olive oil on lipid profile, including low-density lipoprotein subfractions in young healthy Chinese people

The aim of this study is to investigate the effects of palm olein (POL), cocoa butter (CB) and extra virgin olive oil (EVOO) on the lipid profile and low-density lipoprotein subfractions in a young, healthy Chinese population. After screening, 72 subjects were randomly assigned to three groups, and an 18-week randomized crossover trial was conducted. The first phase was a 2-week run-in period, followed by three phases of the 4-week experimental periods with a 2-week washout period between experimental periods. Three groups of subjects alternately consumed a Chinese diet enriched with the different test oils. The various indices of subjects were collected before and after each experimental period. Sixty-seven subjects completed the study, and there were no significant differences in conventional indices amongst the three groups at the beginning of the three experimental periods (p > .05). Each test oil accounted for approximately 40% of total fat intake and approximately 11.3% of the total energy supply. After controlling for dietary interventions, only the serum triglyceride level of the POL-Diet was significantly lower than that of the EVOO-Diet (p = .034), and most indices did not significantly differ amongst the three test oil diets (p > .05). POL, CB and EVOO have almost identical effects on serum lipids.

Interesterified Fats Induce Deleterious Effects on Adipose Tissue and Liver in LDLr-KO Mice

Interesterified fats are being widely used by the food industry in an attempt to replace trans fatty acids. The effect of interesterified fats containing palmitic or stearic acids on lipid metabolism and inflammatory signaling pathways in adipose and hepatic tissues was evaluated. Male LDLr-KO mice were fed a high-fat diet containing polyunsaturated (PUFA), palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR), or stearic interesterified (STEAR INTER) fats for 16 weeks. The expression of genes and protein levels involved in lipid metabolism and inflammatory processes in liver and white adipose tissue was determined by quantitative RT-PCR and by Western blot, respectively. The infiltration of inflammatory cells in hepatic and adipose tissues was determined by eosin and hematoxylin, while liver collagen content was determined by Sirius Red staining. Both interesterified fats increased liver collagen content and JNK phosphorylation. Additionally, the STEAR INTER group developed nonalcoholic steatohepatitis (NASH) associated with higher neutrophil infiltration. PALM INTER induced adipose tissue expansion and enlargement of adipocytes. Furthermore, PALM INTER triggered increased IKK phosphorylation and TNFα protein content, conditions associated with the upstream activation of the NFkB signaling pathway. STEAR INTER induced NASH, while PALM INTER triggered hepatic fibrosis and adipocyte hypertrophy with inflammatory response in LDLr-KO mice.

High-Fat Meal–Induced Changes in Markers of Inflammation and Angiogenesis in Healthy Adults Who Differ by Age and Physical Activity Level

Background

Inflammation and angiogenesis are key facets of cardiovascular disease pathophysiology. Age and physical activity level can influence fasting systemic inflammation, but the impact of these factors on postprandial inflammation is unknown. In addition, markers of angiogenesis have never been tested in the context of a single high-fat meal (HFM).

Objective

The purpose of this study was to investigate the effects of an HFM on markers of inflammation and angiogenesis in individuals of different ages and physical activity levels.

Methods

Twenty-two healthy adults—8 younger active (YA) adults (4 men, 4 women; mean ± SD age: 25 ± 5 y), 8 older active (OA) adults (4 men, 4 women; 67 ± 5 y), and 6 older inactive (OI) adults (3 men, 3 women; 68 ± 7 y)—consumed an HFM [63% fat (39% saturated fat, 14% monounsaturated fat, 10% polyunsaturated fat), 34% carbohydrate; 12 kcal/kg body mass; 927 ± 154 kcal]. Fourteen inflammatory and 9 angiogenic markers were measured at baseline and 3 and 6 h postmeal.

Results

Significant group effects were observed in interleukin (IL)-10 (YA > OA; P = 0.02), IL-23 (YA > OA; P = 0.02), tumor necrosis factor (TNF)-α (OA < OI; P = 0.04), and vascular endothelial growth factor (VEGF)-C (YA < OA; P = 0.001). IL-8, VEGF-A, VEGF-C, and heparin-binding epidermal growth factor–like growth factor significantly increased, whereas granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1β, IL-5, IL-10, IL-12, IL-13, IL-17A, IL-23, TNF-α, leptin, angiopoietin-2, and follistatin significantly decreased after HFM consumption (P’s < 0.05). Notably, VEGF-A and VEGF-C were significantly higher at 3 h [mean difference: 22.5 pg/mL (VEGF-A); 73.5 pg/mL (VEGF-C)] and 6 h postmeal [mean difference: 26.9 pg/mL (VEGF-A); 81.2 pg/mL (VEGF-C)].

Conclusions

A novel finding of this study was the robust increase in VEGF after an HFM. There were also group differences in several inflammatory markers (IL-10 and IL-23 greater in YA than OA, and TNF-α lower in OA than OI) that suggest a potential influence of age and physical activity level.

Interesterified Palm Olein (IEPalm) and Interesterified Stearic Acid-Rich Fat Blend (IEStear) Have No Adverse Effects on Insulin Resistance: A Randomized Control Trial

Chemically-interesterified (CIE) fats are trans-fat free and are increasingly being used as an alternative to hydrogenated oils for food manufacturing industries to optimize their products' characteristics and nutrient compositions. The metabolic effects of CIE fats on insulin activity, lipids, and adiposity in humans are not well established. We investigated the effects of CIE fats rich in palmitic (C16:0, IEPalm) and stearic (C18:0, IEStear) acids on insulin resistance, serum lipids, apolipoprotein concentrations, and adiposity, using C16:0-rich natural palm olein (NatPO) as the control. We designed a parallel, double-blind clinical trial. Three test fats were used to prepare daily snacks for consumption with a standard background diet over a period of 8 weeks by three groups of a total of 85 healthy, overweight adult volunteers. We measured the outcome variables at weeks 0, 6, and at the endpoint of 8. After 8 weeks, there was no significant difference in surrogate biomarkers of insulin resistance in any of the IE fat diets (IEPalm and IEStear) compared to the NatPO diet. The change in serum triacylglycerol concentrations was significantly lower with the IEStear diet, and the changes in serum leptin and body fat percentages were significantly lower in the NatPO-diet compared to the IEPalm diet. We conclude that diets containing C16:0 and C18:0-rich CIE fats do not affect markers of insulin resistance compared to a natural C16:0-rich fat (NatPO) diet. Higher amounts of saturated fatty acids (SFAs) and longer chain SFAs situated at the sn-1,3 position of the triacylglycerol (TAG) backbones resulted in less weight gain and lower changes in body fat percentage and leptin concentration to those observed in NatPO and IEStear.

Effects of dietary palm olein on the cardiovascular risk factors in healthy young adults

BACKGROUND

Dietary saturated fatty acids are always being hotly debated. Palm olein rich in saturated fatty acids (45.98%) is often considered as being atherogenic nutritionally. There is a lack of information on effects of dietary oil by partially replacing with palm olein on human health.

METHODS

A randomized controlled trial with 88 participants has been conducted to elucidate the effect of palm olein on cardiovascular risk factors.

RESULTS

By comparing the soybean oil group (saturated fatty acids amounted to 23.31%) with the cocoa butter group (saturated fatty acids amounted to 93.76%), no significant difference was found (p > 0.05) in physiological parameters, serum oxidative stress levels, inflammatory factor, glucose metabolism, and lipid profiles of subjects, which are all cardiovascular risk factors. Although results showed that intervention time can influence the cardiovascular risk factors significantly (p < 0.05), there is no relationship between intervention time and dietary oil type.

CONCLUSION

Therefore, partial replacement of dietary oil by palm olein may not affect cardiovascular risk factors in healthy young adults. There are differences between our research and previous researches, which may be due to the different amount of palm olien in diet. Our research will provide a solid foundation for the application of palm olein in human diets and in the food industry.

Pediatric Age Palm Oil Consumption

Palm oil is widely used in the food industry for its chemical/physical properties, low cost and wide availability. Its widespread use has provoked an intense debate about whether it is a potential danger to human health. In a careful review of the scientific literature, we focused on nutritional characteristics and health effects of the use of palm oil with regards to children, seeking to determine whether there is evidence that justifies fears about the health effects of palm oil. Our review showed that palm oil represents a significant source of saturated fatty acids, to which scientific evidence attributes negative health effects when used in excess, especially with regards to cardiovascular diseases. However, to date, there is no evidence about the harmful effects of palm oil on the health of children. Nevertheless, palm oil has possible ill health effects linked to its composition of fatty acids: its consumption is not correlated to risk factors for cardiovascular diseases in young people with a normal weight and cholesterol level; the elderly and patients with dyslipidaemia or previous cardiovascular events or hypertension are at a greater risk. Therefore, the matter is not palm oil itself but the fatty-acid-rich food group to which it belongs. The most important thing is to consume no more than 10% of saturated fatty acids, regardless of their origin and regardless of one’s age. Correct information based on a careful analysis of the scientific evidence, rather than a focus on a singular presumed culprit substance, should encourage better lifestyles.

Effects of Plant Oil Interesterified Triacylglycerols on Lipemia and Human Health

The position of the fatty acids (sn-1, sn-2 and sn-3) (stereospecific numbering (sn)) in triacylglycerol (TAG) molecules produces a characteristic stereospecificity that defines the physical properties of the fats and influences their absorption, metabolism and uptake into tissues. Fat interesterification is a process that implies a positional distribution of fatty acids (FAs) within the TAG molecules, generating new TAG species, without affecting the FA cis-trans natural balance. The interesterified (IE) fats, frequently used in the food industry comprise fats that are rich in long-chain saturated FAs, such as palmitic acid (16:0) and stearic acid (18:0). Within the interesterified fats, a critical role is played by FA occupying the sn-2 position; in fact, the presence of an unsaturated FA in this specific position influences early metabolic processing and postprandial clearance that in turn could induce atherogenesis and thrombogenesis events. Here, we provide an overview on the role of TAG structures and interesterified palmitic and stearic acid-rich fats on fasting and postprandial lipemia, focusing our attention on their physical properties and their effects on human health.

Postprandial lipemia: factoring in lipemic response for ranking foods for their healthiness

One of the limitations for ranking foods and meals for healthiness on the basis of the glycaemic index (GI) is that the GI is subject to manipulation by addition of fat. Postprandial lipemia, defined as a rise in circulating triglyceride containing lipoproteins following consumption of a meal, has been recognised as a risk factor for the development of cardiovascular disease and other chronic diseases. Many non-modifiable factors (pathological conditions, genetic background, age, sex and menopausal status) and life-style factors (physical activity, smoking, alcohol and medication use, dietary choices) may modulate postprandial lipemia. The structure and the composition of a food or a meal consumed also plays an important role in the rate of postprandial appearance and clearance of triglycerides in the blood. However, a major difficulty in grading foods, meals and diets according to their potential to elevate postprandial triglyceride levels has been the lack of a standardised marker that takes into consideration both the general characteristics of the food and the food’s fat composition and quantity. The release rate of lipids from the food matrix during digestion also has an important role in determining the postprandial lipemic effects of a food product. This article reviews the factors that have been shown to influence postprandial lipemia with a view to develop a novel index for ranking foods according to their healthiness. This index should take into consideration not only the glycaemic but also lipemic responses.

Membrane lipid alterations in the metabolic syndrome and the role of dietary oils

The metabolic syndrome is a cluster of pathological conditions, including hypertension, hyperglycemia, hypertriglyceridemia, obesity and low HDL levels that is of great concern worldwide, as individuals with metabolic syndrome have an increased risk of type-2 diabetes and cardiovascular disease. Insulin resistance, the key feature of the metabolic syndrome, might be at the same time cause and consequence of impaired lipid composition in plasma membranes of insulin-sensitive tissues like liver, muscle and adipose tissue. Diet intervention has been proposed as a powerful tool to prevent the development of the metabolic syndrome, since healthy diets have been shown to have a protective role against the components of the metabolic syndrome. Particularly, dietary fatty acids are capable of modulating the deleterious effects of these conditions, among other mechanisms, by modifications of the lipid composition of the membranes in insulin-sensitive tissues. However, there is still scarce data based of high-level evidence on the effects of dietary oils on the effects of the metabolic syndrome and its components. This review summarizes the current knowledge on the effects of dietary oils on improving alterations of the components of the metabolic syndrome. It also examines their influence in the modulation of plasma membrane lipid composition and in the functionality of membrane proteins involved in insulin activity, like the insulin receptor, GLUT-4, CD36/FAT and ABCA-1, and their effect in the metabolism of glucose, fatty acids and cholesterol, and, in turn, the key features of the metabolic syndrome. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Milk protein-based formulas containing different oils affect fatty acids balance in term infants: A randomized blinded crossover clinical trial

BACKGROUND

Palm olein is used in infant formula fat blends in order to match the fatty acid profile of human milk. While the effects on fatty acid balance have been evaluated, the use of palm olein in combination with palm kernel oil and supplementation with docosahexaenoic acid (DHA) and arachidonic acid (ARA) has not been similarly assessed in infants. This study evaluated the effects of infant formulas containing different fat compositions on the balance of fat, fatty acids, and calcium.

METHODS

In this randomized, crossover, double-blinded study, 33 healthy term infants (68-159 ± 3 days of age at enrollment) were fed two formulas for 14 days in a tolerance period, followed by a 4-day metabolic balance period in 17 of the male subjects. The study compared two commercially available milk-based powdered formulas in Brazil; the PALM formula contained palm olein (44%), kernel palm oil (21.7%), and canola oil (18.5%) as the predominant fats, whereas the NoPALM formula contained other fat sources.

RESULTS

Fat absorption (%) was greater for NoPALM versus PALM-fed infants (96.55 and 95.50%, respectively; p = 0.023). The absorption percentage of palmitic acid (C16:0) did not differ significantly between formulas (p > 0.05), but this acid was excreted at significantly higher concentrations in the PALM (29.42 mg/kg/day) than in the NoPALM (12.28 mg/kg/day) formula groups. DHA and ARA absorption percentages were also higher in NoPALM-fed infants. Calcium absorption was higher in NoPALM-fed infants (58.00%) compared to those fed PALM (40.90%), but the difference was not significant (p = 0.104) when calcium intake was used as a covariate. However, calcium retention was higher in NoPALM-fed infants compared to that in PALM-fed infants with or without calcium intake as a covariate. Adverse events did not differ between groups (p > 0.05).

CONCLUSIONS

The absorption of essential fatty acids was similar for both formulas; however, long-chain polyunsaturated fatty acids (DHA and ARA) were better absorbed from the NoPALM formula. Fat absorption and calcium retention were lower in term infants fed the PALM-based formula.

CLINICAL TRIAL REGISTRATION

Clinicaltrial.gov # NCT00941564 .

Magnitude and Timing of the Postprandial Inflammatory Response to a High-Fat Meal in Healthy Adults: A Systematic Review

Research findings over the past several decades have shown that inflammation is a prominent feature of many chronic diseases, with poor diet being one likely inflammatory stimulus. Specifically, a single high-fat meal (HFM) has been suggested to increase inflammation, although there is currently no consensus with regard to the specific changes in many of the proinflammatory markers that are frequently assessed after an HFM. The aim of this systematic review was to objectively describe the postprandial timing and magnitude of changes in 5 common inflammatory markers: interleukin (IL) 6, C-reactive protein (CRP), tumor necrosis factor (TNF) α, IL-1β, and IL-8. Ten relevant databases were searched, yielding 494 results, of which 47 articles met the pre-established inclusion criteria: 1) healthy men and women aged 18-60 y, 2) consuming a single HFM (≥30% fat, ≥500 kcal), and 3) assessing relevant inflammatory markers postmeal for ≥2 h. The only marker found to consistently change in the postprandial period was IL-6: on average, from a baseline of ∼1.4 pg/mL, it peaked at ∼2.9 pg/mL ∼6 h post-HFM (an average relative change of ∼100%). CRP, TNF-α, IL-1β, and IL-8 did not change significantly in 79% (23 of 29), 68% (19 of 28), 67% (2 of 3), and 75% (3 of 4) of included studies, respectively. We conclude that there is strong evidence that CRP and TNF-α are not responsive at the usual time scale observed in postprandial studies in healthy humans younger than age 60 y. However, future research should further investigate the role of IL-6 in the postprandial period, because it routinely increases even in healthy participants. We assert that the findings of this systematic review on markers of inflammation in the postprandial period will considerably aid in informing future research and advancing clinical knowledge.

Effects of a Plant Sterol or Stanol Enriched Mixed Meal on Postprandial Lipid Metabolism in Healthy Subjects

Background

Evidence is increasing that plant sterols and stanols not only lower fasting serum low-density lipoprotein concentrations, but also those of triglycerides (TG). Insight into effects of these components on postprandial TG metabolism, an emerging risk factor for cardiovascular disease, is missing.

Objective

Our objective was to examine the 8-hour postprandial response after consuming plant sterol or stanol enriched margarine as part of a mixed meal.

Methods

This postprandial study was part of a randomized crossover study in which 42 subjects consumed plant sterol enriched (3 g/d plant sterols), plant stanol enriched (3 g/d plant stanols), and control margarines for 4 weeks. After each period, subjects consumed a shake enriched with 3g plant sterols (sterol period), 3g plant stanols (stanol period) or no addition (control period). Subjects received a second shake with no addition after 4 hours.

Results

TG and apoB48 incremental areas under the curves (iAUC) of the total (0-8h) and 1^st meal response (0-4h) were comparable between the meals and in all age categories (I:18-35y, II:36-52y, III:53-69y). In subjects aged 53-69y, TG iAUC after the 2^nd meal (4-8h) was higher in the stanol period as compared with the sterol (63.1±53.0 mmol/L/min; P < 0.01) and the control period (43.2±52.4 mmol/L/min; P < 0.05). ApoB48 iAUC after the 2^nd meal was higher after the stanol than after the sterol period (67.1±77.0 mg/L/min; P < 0.05) and tended to be higher than after the control period (43.1±64.5 mg/L/min; P = 0.08) in subjects aged 53-69y. These increased postprandial responses may be due to reduced lipoprotein lipase activity, since postprandial apoCIII/II ratios were increased after stanol consumption compared with the control meal.

Conclusion

Postprandial TG and apoB48 responses are age-dependently increased after plant stanol consumption, which might be related to a changed clearance of triglyceride-rich lipoproteins.

Trial Registration

ClinicalTrials.gov NCT01559428

Modulation of postprandial lipaemia by a single meal containing a commonly consumed interesterified palmitic acid-rich fat blend compared to a non-interesterified equivalent

Purpose

Interesterification of palm stearin and palm kernal (PSt/PK) is widely used by the food industry to create fats with desirable functional characteristics for applications in spreads and bakery products, negating the need for trans fatty acids. Previous studies have reported reduced postprandial lipaemia, an independent risk factor for CVD, following interesterified (IE) palmitic and stearic acid-rich fats that are not currently widely used by the food industry. The current study investigates the effect of the most commonly consumed PSt/PK IE blend on postprandial lipaemia.

Methods

A randomised, controlled, crossover (1 week washout) double-blind design study (n = 12 healthy males, 18–45 years), compared the postprandial (0–4 h) effects of meals containing 50 g fat [PSt/PK (80:20); IE vs. non-IE] on changes in plasma triacylglycerol (TAG), glucose, glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), insulin, gastric emptying (paracetamol concentrations) and satiety (visual analogue scales).

Results

The postprandial increase in plasma TAG was higher following the IE PSt/PK versus the non-IE PSt/PK, with a 51 % greater incremental area under the curve [mean difference with 95 % CI 41 (23, 58) mmol/L min P = 0.001]. The pattern of lipaemia was different between meals; at 4-h plasma TAG concentrations declined following the IE fat but continued to rise following the non-IE fat. Insulin, glucose, paracetamol, PYY and GIP concentrations increased significantly after the test meals (time effect; P < 0.001 for all), but did not differ between test meals. Feelings of fullness were higher following the non-IE PSt/PK meal (diet effect; P = 0.034). No other significant differences were noted.

Conclusions

Interesterification of PSt/PK increases early phase postprandial lipaemia (0–4 h); however, further investigation during the late postprandial phase (4–8 h) is warranted to determine the rate of return to baseline values.

Trial registration number

Clinicaltrials.gov as NCT02365987.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-016-1284-z) contains supplementary material, which is available to authorized users.

The Increasing Use of Interesterified Lipids in the Food Supply and Their Effects on Health Parameters

A variety of modified fats that provide different functionalities are used in processed foods to optimize product characteristics and nutrient composition. Partial hydrogenation results in the formation of trans FAs (TFAs) and was one of the most widely used modification processes of fats and oils. However, the negative effects of commercially produced TFAs on serum lipoproteins and risk for cardiovascular disease resulted in the Institute of Medicine and the 2010 US Dietary Guidelines for Americans both recommending that TFA intake be as low as possible. After its tentative 2013 determination that use of partially hydrogenated oils is not generally regarded as safe, the FDA released its final determination of the same in 2015. Many food technologists have turned to interesterified fat as a replacement. Interesterification rearranges FAs within and between a triglyceride molecule by use of either a chemical catalyst or an enzyme. Although there is clear utility of interesterified fats for retaining functional properties of food, the nutrition and health implications of long-term interesterified fat consumption are less well understood. The Technical Committee on Dietary Lipids of the North American Branch of the International Life Sciences Institute sponsored a workshop to discuss the health effects of interesterified fats, identify research needs, and outline considerations for the design of future studies. The consensus was that although interesterified fat production is a feasible and economically viable solution for replacing dietary TFAs, outstanding questions must be answered regarding the effects of interesterification on modifying certain aspects of lipid and glucose metabolism, inflammatory responses, hemostatic parameters, and satiety.

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.

Effects of amount and type of dietary fats on postprandial lipemia and thrombogenic markers in individuals with metabolic syndrome

OBJECTIVE

Postprandial lipemia has been reported to affect endothelial function by thrombogenic and inflammatory pathways. We set out to investigate the impact of a) specific amount (50 g vs 20 g fat), and b) type of fatty acids (saturated, monounsaturated or n-6 polyunsaturated fatty acids; SFA, MUFA, PUFA) on postprandial lipemia, thrombogenic and inflammatory factors in metabolic syndrome subjects.

DESIGN

30 subjects (15 men, 15 women) participated in a double-blind, randomized crossover design study with both the subjects and investigators blinded to treatments. Blood samples were collected at fasting and 30 min, hourly interval for a total of 6 h.

RESULTS

As expected, lower triacylglycerol response was observed for low fat/high carbohydrate meal; whereas no difference was detected between the types of fatty acids. The incremental area under the curve (iAUC) for low fat/high carbohydrate meal was 70%, 81% and 61% lower than the SFA, MUFA and PUFA meals, respectively. The iAUC 0-6 h for triacylglycerol was 42% lower in women compared with the men (P = 0.024), with the similar trend observed for non-esterified fatty acids. There were significant meal × time interaction (P = 0.000) for plasma plasminogen activator inhibitor-1 and thromboxane B2 (P = 0.022) from baseline. No differences were observed between meals for plasma D-dimer, interleukin-6, interleukin-1β, tumor necrosis factor-α and high sensitivity C-reactive protein.

CONCLUSION

These data indicate that in metabolic syndrome subjects, only the amount of dietary fatty acids affects postprandial lipemia but both amount and type of dietary fats alter thrombogenic factors.

TRIAL REGISTRATION

The study was registered at Clinicaltrials.gov (NCT01571947).

Palm Oil Consumption Increases LDL Cholesterol Compared with Vegetable Oils Low in Saturated Fat in a Meta-Analysis of Clinical Trials

BACKGROUND

Palm oil contains a high amount of saturated fat compared with most other vegetable oils, but studies have reported inconsistent effects of palm oil on blood lipids.

OBJECTIVE

We systematically reviewed the effect of palm oil consumption on blood lipids compared with other cooking oils using data from clinical trials.

METHODS

We searched PubMed and the Cochrane Library for trials of at least 2 wk duration that compared the effects of palm oil consumption with any of the predefined comparison oils: vegetable oils low in saturated fat, trans fat-containing partially hydrogenated vegetable oils, and animal fats. Data were pooled by using random-effects meta-analysis.

RESULTS

Palm oil significantly increased LDL cholesterol by 0.24 mmol/L (95% CI: 0.13, 0.35 mmol/L; I(2) = 83.2%) compared with vegetable oils low in saturated fat. This effect was observed in randomized trials (0.31 mmol/L; 95% CI: 0.20, 0.42 mmol/L) but not in nonrandomized trials (0.03 mmol/L; 95% CI: -0.15, 0.20 mmol/L; P-difference = 0.02). Among randomized trials, only modest heterogeneity in study results remained after considering the test oil dose and the comparison oil type (I(2) = 27.5%). Palm oil increased HDL cholesterol by 0.02 mmol/L (95% CI: 0.01, 0.04 mmol/L; I(2) = 49.8%) compared with vegetable oils low in saturated fat and by 0.09 mmol/L (95% CI: 0.06, 0.11 mmol/L; I(2) = 47.8%) compared with trans fat-containing oils.

CONCLUSIONS

Palm oil consumption results in higher LDL cholesterol than do vegetable oils low in saturated fat and higher HDL cholesterol than do trans fat-containing oils in humans. The effects of palm oil on blood lipids are as expected on the basis of its high saturated fat content, which supports the reduction in palm oil use by replacement with vegetable oils low in saturated and trans fat. This systematic review was registered with the PROSPERO registry at http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42012002601#.VU3wvSGeDRZ as CRD42012002601.

Effect of dietary Fatty acids on human lipoprotein metabolism: a comprehensive update

Dyslipidemia is a major risk factor for cardiovascular disease (CVD). Dietary fatty-acid composition regulates lipids and lipoprotein metabolism and may confer CVD benefit. This review updates understanding of the effect of dietary fatty-acids on human lipoprotein metabolism. In elderly participants with hyperlipidemia, high n-3 polyunsaturated fatty-acids (PUFA) consumption diminished hepatic triglyceride-rich lipoprotein (TRL) secretion and enhanced TRL to low-density lipoprotein (LDL) conversion. n-3 PUFA also decreased TRL-apoB-48 concentration by decreasing TRL-apoB-48 secretion. High n-6 PUFA intake decreased very low-density lipoprotein (VLDL) cholesterol and triglyceride concentrations by up-regulating VLDL lipolysis and uptake. In a study of healthy subjects, the intake of saturated fatty-acids with increased palmitic acid at the sn-2 position was associated with decreased postprandial lipemia. Low medium-chain triglyceride may not appreciably alter TRL metabolism. Replacing carbohydrate with monounsaturated fatty-acids increased TRL catabolism. Trans-fatty-acid decreased LDL and enhanced high-density lipoprotein catabolism. Interactions between APOE genotype and n-3 PUFA in regulating lipid responses were also described. The major advances in understanding the effect of dietary fatty-acids on lipoprotein metabolism has centered on n-3 PUFA. This knowledge emphasizes the importance of regulating lipoprotein metabolism as a mode to improve plasma lipids and potentially CVD risk. Additional studies are required to better characterize the cardiometabolic effects of other dietary fatty-acids.

An acute intake of plant stanol esters alters immune-related pathways in the jejunum of healthy volunteers

Plant sterols and stanols inhibit intestinal cholesterol absorption and consequently lower serum LDL-cholesterol (LDL-C) concentrations. The underlying mechanisms are not yet known. In vitro and animal studies have suggested that changes in intestinal sterol metabolism are attributed to the LDL-C-lowering effects of plant stanol esters. However, similar studies in human subjects are lacking. Therefore, we examined the effects of an acute intake of plant stanol esters on gene expression profiles of the upper small intestine in healthy volunteers. In a double-blind cross-over design, fourteen healthy subjects (eight female and six male; age 21-55 years), with a BMI ranging from 21 to 29 kg/m², received in random order a shake with or without plant stanol esters (4 g). At 5 h after consumption of the shake, biopsies were taken from the duodenum (around the papilla of Vater) and from the jejunum (20 cm distal from the papilla of Vater). Microarray analysis showed that the expression profiles of genes involved in sterol metabolism were not altered. Surprisingly, the pathways involved in T-cell functions were down-regulated in the jejunum. Furthermore, immunohistochemical analysis showed that the number of CD3 (cluster of differentiation number 3), CD4 (cluster of differentiation number 4) and Foxp3⁺ (forkhead box P3-positive) cells was reduced in the plant stanol ester condition compared with the control condition, which is in line with the microarray data. The physiological and functional consequences of the plant stanol ester-induced reduction of intestinal T-cell-based immune activity in healthy subjects deserve further investigation.

Saturated Fats Versus Polyunsaturated Fats Versus Carbohydrates for Cardiovascular Disease Prevention and Treatment

The effects of saturated fatty acids (SFAs) on cardiovascular disease (CVD) risk are modulated by the nutrients that replace them and their food matrices. Replacement of SFAs with polyunsaturated fatty acids has been associated with reduced CVD risk, although there is heterogeneity in both fatty acid categories. In contrast, replacement of SFAs with carbohydrates, particularly sugar, has been associated with no improvement or even a worsening of CVD risk, at least in part through effects on atherogenic dyslipidemia, a cluster of traits including small, dense low-density lipoprotein particles. The effects of dietary SFAs on insulin sensitivity, inflammation, vascular function, and thrombosis are less clear. There is growing evidence that SFAs in the context of dairy foods, particularly fermented dairy products, have neutral or inverse associations with CVD. Overall dietary patterns emphasizing vegetables, fish, nuts, and whole versus processed grains form the basis of heart-healthy eating and should supersede a focus on macronutrient composition.

PALMITIC AND OLEIC ACIDS AND THEIR ROLE IN PATHOGENESIS OF ATHEROSCLEROSIS

On the basis of phylogenetic theory of general pathology, the cause of a noninfectious disease whose occurrence in a population is more than 5–7% is an impaired biological function or reaction to the environment. From the general biology viewpoint, high mortality rate related to cardio-vascular diseases and atherosclerosis (intercellular deficiency of polyenic fatty acids (PFA)) is just extinction of the Homo sapiens population upon adaptation to new environmental factors. The biological function of throphology (feeding) and biological reaction of exotrophy (external feeding) are impaired in several aspects, the major of which is nonphysiologically high dietary content of saturated fatty acids, primarily, of palmitic fatty acid (FA). The lipoprotein system formed at early stages of phylogenesis cannot transport and provide physiological deposition of great amounts of palmitic FA, which leads to the development of an adaption (compensatory) and accumulation disease. This results in hypermipidemia, impaired bioavailability of PFA to cells, compesatory production of humoral mediators from ω-9 eicosatrienoic mead FA, disorders in physiological parameters of cell plasma membrane and integral proteins, nonphysiological conformation of apoВ-100 in lipoproteins, formation of ligandless lipoproteins (biological litter) and impairments in the biological function of endoecology, utilization of ligandless lipoproteins in arterial intima by phylogenetically early macrophages that do not hydrolyze polyenic cholesterol esters, increase in the intensity of the biological reaction of inflammation, and destructive and inflammatory lesions in arterial intima of an atheromatosis or atherothrombosis type. Atheromatous masses are catabolites of PFA which were not internalized by phylogenetically late cells via receptor-mediated pathway.

Effects of stearidonic acid on serum triacylglycerol concentrations in overweight and obese subjects: a randomized controlled trial

BACKGROUND/OBJECTIVES

Eicosapentaenoic acid (EPA), which may reduce the risk for coronary heart disease (CHD), can be synthesized at low rates from α-linolenic acid (ALA). The rate-limiting step for this conversion is the Δ6-desaturation of ALA into stearidonic acid (SDA). Thus providing oils rich in SDA may increase endogenous synthesis of EPA, which may subsequently lower serum triacylglycerol concentrations, an effect frequently observed after EPA supplementation. We therefore studied the effects of Echium oil on serum triacylglycerol concentrations and the omega-3 index, which correlate negatively with the risk for CHD.

SUBJECTS/METHODS

A randomized, double-blind, placebo-controlled crossover trial was conducted, in which 36 healthy overweight and slightly obese subjects daily received 10 g of Echium oil (providing 1.2 g of SDA) or a high oleic acid sunflower oil (HOSO) as control for 6 weeks, with a washout period of at least 14 days. Four subjects dropped out. Differences between periods were tested for statistical significance (P<0.05) using a paired t-test.

RESULTS

Serum triacylglycerol and other lipid concentrations were not significantly affected by consumption of Echium oil compared with HOSO. Echium oil significantly increased percentage of EPA in red blood cell (RBC) membranes with 0.14 ± 0.25% (mean ± s.d.) compared with HOSO (P=0.02). No significant effects on docosahexaenoic acid in RBC membranes or on the omega-3 index were found.

CONCLUSIONS

In healthy overweight and slightly obese subjects, an increased intake of SDA from Echium oil does not lower serum triacylglycerol concentrations. Despite an increase in the percentage of EPA in RBC membranes, the omega-3 index was not changed.

An interesterified palm olein test meal decreases early-phase postprandial lipemia compared to palm olein: a randomized controlled trial

Palm oil that has been interesterified to produce a higher proportion of palmitic acid (16:0) in the sn-2 position reduces postprandial lipemia in young, normolipidemic men and women, but effects in older subjects with higher fasting triacylglycerol (TAG) concentrations are unknown. We tested the hypothesis that high-fat meals rich in interesterified palm olein (IPO) decrease lipemia and alter plasma lipoprotein fraction composition compared to native palm olein (NPO) in men aged 40-70 years with fasting TAG concentrations ≥1.2 mmol/L. Postprandial changes in plasma lipids following meals containing 75 g fat (NPO and IPO) were compared using a randomized, double-blind crossover design (n = 11). Although there were no significant differences in plasma TAG concentrations between meals over the total 6-h postprandial measurement period, IPO resulted in a decreased plasma TAG response during the first 4 h of the postprandial period (iAUC 1.65 mmol/L h, 95% CI 1.01-2.29) compared to NPO (iAUC 2.33 mmol/L h, 95% CI 1.58-3.07); meal effect P = 0.024. Chylomicron fraction TAG concentrations at 4-6 h were slightly reduced following IPO compared to NPO [NPO-IPO mean difference 0.29 mmol/L (95% CI -0.01-0.59), P = 0.055]. There were no differences in IDL fraction TAG, cholesterol or apolipoprotein B48 concentrations following IPO compared with NPO. In conclusion, consuming a meal containing palm olein with a higher proportion of 16:0 in the sn-2 position decreases postprandial lipemia compared to native palm olein during the early phase of the postprandial period in men with higher than optimal fasting triacylglycerol concentrations.