Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men and women

Analysis of 26 Studies of the Impact of Coconut Oil on Lipid Parameters: Beyond Total and LDL Cholesterol

Coconut oil (CNO) is often characterized as an "artery-clogging fat" because it is a predominantly saturated fat that ostensibly raises total cholesterol (TChol) and LDL cholesterol (LDL-C). Whereas previous analyses assessed CNO based on the relative effects on lipid parameters against other fats and oils, this analysis focuses on the effects of CNO itself. Here, we review the literature on CNO and analyze 984 lipid profile data sets from 26 CNO studies conducted over the past 40 years. This analysis shows considerable heterogeneity among CNO studies regarding participant selection, the amount consumed, and the study duration. The analysis reveals that, overall, CNO consumption gives variable TChol and LDL-C values, but that the HDL-cholesterol (HDL-C) values increase and triglycerides (TG) decrease. This holistic lipid assessment, together with the consideration of lipid ratios, shows that CNO does not pose a health risk for heart disease. Because the predominantly medium-chain fatty acid profile of CNO is significantly different from that of lard and palm oil, studies using these as reference materials do not apply to CNO. This paper concludes that the recommendation to avoid consuming coconut oil due to the risk of heart disease is not justified.

Changes in serum lipids following consumption of coconut oil and palm olein oil: A sequential feeding crossover clinical trial

BACKGROUND

High incidence of cardiovascular disease (CVD) in South Asia is linked to genetic predisposition and diets high in saturated fatty acids (SFAs). Increased CVD prevalence correlates with rising palm oil consumption in some South Asian countries, where coconut oil and palm olein oil are primary SFA sources.

OBJECTIVE

Compare the effects of coconut oil and palm olein oil on serum lipoprotein lipids and biochemical parameters in healthy adults.

METHODS

A sequential feeding crossover clinical trial with two feeding periods of 8 weeks each was conducted among 40 healthy adults. Participants were provided palm olein oil in the first feeding period followed by coconut oil with a 16-week washout period in between. The outcomes measured were the difference in serum low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C), TC/HDL-C ratio, triglycerides (TG), very-low-density lipoprotein cholesterol (VLDL-C), fasting plasma glucose (FPG), and liver enzymes.

RESULTS

Thirty-seven participants completed the study. LDL-C decreased by 13.0 % with palm olein oil (p < 0.001) and increased by 5.6 % with coconut oil (p = 0.044), showing a significant difference (p < 0.001). TC decreased by 9.9 % with palm olein oil (p < 0.001) and increased by 4.0 % with coconut oil (p = 0.044).

CONCLUSION

Palm olein oil consumption resulted in more favorable changes in lipid-related CVD risk factors (TC, LDL-C, TC:HDL-C, and FPG) compared to coconut oil. Clinical Trial Registry number and website where it was obtained: (SLCTR/2019/034); https://slctr.lk/trials/slctr-2019-034.

The effect of coconut oil and palm oil on anthropometric parameters: a clinical trial

BACKGROUND

During recent years several studies have investigated the impact of different dietary oils on body weight. They have shown differential positive and negative effects on anthropometry. We investigated the effects of palm and coconut oils on body weight and other anthropometric parameters, considering their importance as a primary source of saturated fat, controlling for other confounding variable such as total energy intake.

METHODS

The study was conducted as a sequential feeding clinical trial with 40 healthy men and women divided into two feeding periods of initial palm oil (8 weeks) and subsequent coconut oil (8 weeks), with a 16-week washout period in between. Each participant received a pre-determined volume of each oil, which were integrated into their routine main meals and snacks during the respective study periods. Changes in body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) were evaluated. Physical activity levels and dietary intake were also evaluated as potential confounding factors.

RESULTS

Thirty-seven participants completed both oil treatment periods. The mean (± SD) age of the participants was 39 (± 13.1) years. There were no significant differences in any of the anthropometric parameters between the initial point of feeding coconut oil and the initial point of feeding palm oil. Following both oil treatment phases, no significant changes in the subjects' body weight, BMI, or other anthropometric measurements (WC, HC, and WHR) were observed.

CONCLUSION

Neither coconut oil nor palm oil significantly changed anthropometry-related cardiovascular risk factors such as body weight, BMI, WC, HC, and WHR.

TRIAL REGISTRATION

Sri Lankan Clinical Trial Registry: SLCTR/2019/034 on 4th October 2019 ( https://slctr.lk/trials/slctr-2019-034 ).

Effect of Extra Virgin Olive Oil on Anthropometric Indices, Inflammatory and Cardiometabolic Markers: a Systematic Review and Meta-Analysis of Randomized Clinical Trials

BACKGROUND

A large body of literature associated extra virgin olive oil (EVOO) consumption with low risk of cardiovascular disease and mortality. However, findings from clinical trials related to EVOO consumption on blood pressure, lipid profile, and anthropometric and inflammation parameters are not univocal.

OBJECTIVES

The aim of this systematic review and meta-analysis was to evaluate the effect of EVOO consumption on cardiometabolic risk factors and inflammatory mediators.

METHODS

We searched PubMed/MEDLINE, Scopus, and Cochrane up through 31 March, 2023, without any particular language limitations, in order to identify randomized controlled trials (RCTs) that examined the effects of EVOO consumption on cardiometabolic risk factors, inflammatory mediators, and anthropometric indices. Outcomes were summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) estimated from Hedge's g and random-effects modeling. Heterogeneity was assessed by Cochran Q-statistic and quantified (I2).

RESULTS

Thirty-three trials involving 2020 participants were included. EVOO consumption was associated with a significant decrease in insulin (n = 10; SMD: -0.28; 95% CI: -0.51, -0.05; I2 = 48.57%) and homeostasis model assessment of insulin resistance levels (HOMA-IR) (n = 9; SMD: -0.19; 95% CI: -0.35, -0.03; I2 = 00.00%). This meta-analysis indicated no significant effect of consuming EVOO on fasting blood glucose, triglycerides, total cholesterol, low density lipoproteins, very low density lipoproteins, high density lipoproteins, Apolipoprotein (Apo) A-I and B, lipoprotein a, blood pressure, body mass index, waist circumference, waist to hip ratio, C-reactive protein, interleukin-6, interleukin-10, and tumor necrosis factor α levels (P > 0.05).

CONCLUSIONS

The present evidence supports a beneficial effect of EVOO consumption on serum insulin levels and HOMA-IR. However, larger well-designed RCTs are still required to evaluate the effect of EVOO on cardiometabolic risk biomarkers. This study was registered in PROSPERO as CRD42023409125.

Perspective: The Saturated Fat-Unsaturated Oil Dilemma: Relations of Dietary Fatty Acids and Serum Cholesterol, Atherosclerosis, Inflammation, Cancer, and All-Cause Mortality

PUFAs are known to regulate cholesterol synthesis and cellular uptake by multiple mechanisms that do not involve SFAs. Polymorphisms in any of the numerous proteins involved in cholesterol homeostasis, as a result of genetic variation, could lead to higher or lower serum cholesterol. PUFAs are susceptible to lipid peroxidation, which can lead to oxidative stress, inflammation, atherosclerosis, cancer, and disorders associated with inflammation, such as insulin resistance, arthritis, and numerous inflammatory syndromes. Eicosanoids from arachidonic acid are among the most powerful mediators that initiate an immune response, and a wide range of PUFA metabolites regulate numerous physiological processes. There is a misconception that dietary SFAs can cause inflammation, although endogenous palmitic acid is converted to ceramides and other cell constituents involved in an inflammatory response after it is initiated by lipid mediators derived from PUFAs. This article will discuss the many misconceptions regarding how dietary lipids regulate serum cholesterol, the fact that all-cause death rate is higher in humans with low compared with normal or moderately elevated serum total cholesterol, the numerous adverse effects of increasing dietary PUFAs or carbohydrate relative to SFAs, as well as metabolic conversion of PUFAs to SFAs and MUFAs as a protective mechanism. Consequently, dietary saturated fats seem to be less harmful than the proposed alternatives.

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.

Effect of coconut oil on cardio-metabolic risk: A systematic review and meta-analysis of interventional studies

BACKGROUND AND AIMS

High total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) could be major risk factors for cardiovascular disease burden among high risk populations especially in South Asians. This systematic review and meta-analysis aimed to quantify the effects of coconut oil compared with other oils and fats on cardio-metabolic parameters.

METHODS

PubMed, Scopus and Web of Science were systematically searched. The main outcomes included are lipid and glycemic parameters. Subgroup analyses were performed to evaluate individual comparisons of vegetable oils and animal fat with coconut oil. Data were pooled using random-effects meta-analysis.

RESULTS

Coconut oil consumption significantly increased TC by 15.42 mg/dL (95% CI, 8.96-21.88, p < 0.001), LDL-C by 10.14 mg/dL (95% CI, 4.44-15.84, p < 0.001) and high density lipoprorein cholesterol (HDL-C) by 2.61 mg/dL (95% CI, 0.95-4.26, p = 0.002), and significantly decreased glycosylated hemoglobin (HbA1c) by 0.39 mg/dL (95% CI, -0.50 to -0.27, p < 0.001) but, it had no effects on triglycerides (TG), (4.25 mg/dL; 95% CI, -0.49-8.99, p = 0.08) when compared with the control group. Sub-group analysis demonstrated that coconut oil significantly increased TC and LDL-C over corn, palm, soybean and safflower oils and not over olive oil. Compared with butter, coconut oil showed a better pattern in cardio-metabolic markers by significantly increasing HDL-C (4.38 mg/dL, 95% CI, 0.40 to 8.36, p = 0.03) and decreasing LDL-C (-14.90 mg/dL, 95% CI, -23.02 to-6.77, p < 0.001).

CONCLUSIONS

Our results suggest that coconut oil consumption results in significantly higher TC, LDL-C and HDL-C than other oils. Consumption of coconut oil can be one of the risk factors for CVDs in South Asians.

Variability of Volatile Compounds in the Medicinal Plant Dendrobium officinale from Different Regions

Dendrobium officinale Kimura et Migo, a rare and traditional medicinal plant, contains many nutrients such as polysaccharides, alkaloids, amino acids and so on. Different growth environment and intraspecific hybridization of different germplasm resources lead to large differences in the yield, quality and medicinal value of D. officinale. Here, the volatile compounds of D. officinale from four producing regions (Zhejiang, Fujian, Yunnan and Jiangxi) were analyzed to provide a certain reference value for the selection of a specific medicinal component in D. officinale breeding. Fresh stems of D. officinale germplasm resources were collected, and the chemical constituents were determined by gas chromatography-mass spectrometry. A total of 101 volatile compounds were identified, of which esters and alcohols accounted for 23 and 22. Hexacosane is the highest relative content of all volatile components. The highest content of hexacosane was observed in YA1 from Yunnan was 34.41%, and the lowest (23.41%) in JA1 from Jiangxi. Moreover, 5-10 unique substances were determined in different regions. A total of 17 medicinal components were detected, and three unique medicinal components were detected only in YA1, revealing that YA1 can provide raw materials for the application of specific medicinal substances extraction. A total of four toxic components were detected, but no toxic components were detected in JA1 from Jiangxi, suggested that the germplasm resources from Jiangxi could be exploited efficiently for breeding superior D. officinale specimens. The results provide a theoretical basis for the collection, protection and utilization of D. officinale germplasm resources in different regions.

The Effects of Palm Oil on Plasma and Serum Lipid Parameters: A Systematic Review on Animal Intervention Studies

Background: Accumulative evidences on the beneficial effects of palm oil are progressively reported; however, there are still several controversies related to their effects on the risks of cardiovascular disease (CVD). This review explores the effects of palm oil and its liquid fraction namely palm olein, which is commonly used as cooking oil on four lipid parameters; total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), which play an important role as CVD-related biomarkers. A systematic review of the literature was conducted to identify the relevant studies on palm oil and the lipid parameters specifically focusing on the in-vivo animal model.

Methods: A comprehensive search was conducted in Medline via EBSCOhost, Medline via OVID and Scopus. Studies were limited to the English language published between the years of 2000 and 2019. The main inclusion criteria were as follows: (1) Study with in-vivo animal experiments [the animal should be limited to mammals] (2) Study should have evaluated the effects of palm oil or palm olein on plasma or serum lipid parameter (3) Study should have used palm oil or palm olein in the form of pure or refined oil (4) The treatment of palm oil or palm olein was assessed using the following outcomes: plasma or serum TC, TG, HDL-C, and LDL-C concentration (5) Study should have control group and (6) studies on specific fatty acid, fraction enriched tocotrienol and tocopherol, crude palm oil, kernel oil, red palm oil, thermally oxidized palm oil, hydrogenated palm oil, and palm oil or palm olein based products namely margarine, palm milk, butter and cream were excluded. The quality and the risk of bias on the selected studies were assessed using the ARRIVE Guideline and SYRCLE's Risk of Bias tools, respectively.

Results: The literature search successfully identified 17 potentially relevant articles, whereby nine of them met the inclusion criteria. All research articles included in this review were in vivo studies comprising seven rats, one hamster and one mice model.

Conclusion: Significant positive outcomes were observed in several lipid parameters such as TC and LDL-C. The evidence from this review supported that palm oil and palm olein possess high potential as lipid-lowering agents.

Whole Milk and Full-Fat Dairy Products and Hypertensive Risks

Lifestyle modifications in the form of diet and exercise are generally a first-line approach to reduce hypertensive risk and overall cardiovascular disease (CVD) risk. Accumulating research evidence has revealed that consumption of non- and low-fat dairy products incorporated into the routine diet is an effective means to reduce elevated blood pressure and improve vascular functions. However, the idea of incorporating whole-fat or full-fat dairy products in the normal routine diet as a strategy to reduce CVD risk has been met with controversy. The aim of this review is to review both sides of the argument surrounding saturated fat intake and CVD risk from the standpoint of dairy intake. Throughout the review, we examined observational studies on relationships between CVD risk and dairy consumption, dietary intervention studies using non-fat and whole-fat dairy, and mechanistic studies investigating physiological mechanisms of saturated fat intake that may help to explain increases in cardiovascular disease risk. Currently available data have demonstrated that whole-fat dairy is unlikely to augment hypertensive risk when added to the normal routine diet but may negatively impact CVD risk. In conclusion, whole-fat dairy may not be a recommended alternative to non- or low-fat dairy products as a means to reduce hypertensive or overall CVD risk.

Hypocholesterolaemic and Anti-Atherogenic Effects of Palm-Based Oils (NoveLin I and NoveLin II) in Cholesterol-Fed Rabbits

NoveLin I and NoveLin II are palm-based oils. NoveLin I has an equal distribution of saturated, monounsaturated and polyunsaturated fatty acids, whereas NoveLin II has a moderate level of monounsaturated fatty acids, and a lower content of saturated and polyunsaturated fatty acids. However, their hypocholesterolaemic and anti-atherogenic effects have not been studied. Therefore, this study aimed to assess the hypocholesterolaemic and anti-atherogenic effects of these oils. Forty male New Zealand White rabbits were divided into four groups and fed with diets containing 35% energy fat with added 0.15% (w/w) dietary cholesterol. Group 1, as the control group (CNO) was fed with a diet containing coconut oil, group 2 and 3 were fed with diets containing either NoveLin I or NoveLin II, and group 4, was fed with diet containing olive oil (OLV) for 100 days. Our results demonstrated that both NoveLin groups have significantly lower total cholesterol and low-density lipoprotein-cholesterol (LDL-C) compared to CNO group and are comparable to the OLV group. Low density lipoprotein-cholesterol/high density lipoprotein-cholesterol (LDL/HDL-C) ratio was significantly lower after the NoveLin II diet but attained significance only in comparison to NoveLin I and CNO groups. Aortic fibrous plaque score was significantly lower in both NoveLin groups compared to CNO group. Our findings suggest that despite the high-fat cholesterol diet, NoveLin II oil resulted in atherogenic effects comparable to olive oil.

Fatty acid regio-specificity of triacylglycerol molecules may affect plasma lipid responses to dietary fats-a randomised controlled cross-over trial

BACKGROUND/OBJECTIVES

Hypercholesterolaemic effects of saturated fatty acids (SFA) may be influenced not only by the chain length, but also by their specific location within the triacylglycerol (TAG) molecule. We examined the hypothesis that dietary fats rich in SFA, but containing mostly unsaturated fatty acids in the sn-2 position with most SFA in sn-1 and -3 (palm olein [PO] and cocoa butter [CB]) will have similar serum lipid outcomes to unsaturated olive oil (OO).

SUBJECTS/METHODS

Thirty-eight participants (20-40 yr, 18.5- ≤ 27.5 kg/m2) completed a 4-week randomised 3 × 3 crossover feeding intervention, preceded by 2-week run-in and separated by 2-week washout periods. Background diet contained 35 percentage of total energy (%E) fat, 18%E protein, 48%E carbohydrates, differing in test fats only (palm olein (PO), CB, OO; 20%E). Total cholesterol (TC)/high density lipoprotein cholesterol (HDL-C) ratio and related variables; TC, HDL-C, low density lipoprotein cholesterol (LDL-C), TAG, apoA1, ApoB, ApoA1 (apolipoprotein A1)/ApoB (apolipoprotein B), lipoprotein (a) (Lp(a)), NEFA, LDL sub-fractions, were assessed pre- and post-intervention. Data were analysed using mixed effects longitudinal models with a P-value < 0.05 considered significant.

RESULTS

Changes in plasma fatty acids (P < 0.05) confirmed compliance; C18:1 increased with OO compared to PO and CB; C16:0 decreased with OO and C18:0 increased following CB. No differences were seen for TC/HDL-C (mean [95%CI] change for PO, 0.08[0.00, 0.15] mmol/L; CB, 0.06 [-0.05, 0.16] mmol/L; and OO, -0.01 [-0.15, 0.13] mmol/L; P = 0.53] or any other parameter including LDL sub-fractions. OO decreased IDL-A compared to PO (-2.2 [-4.31, -0.21] mg/dL, P = 0.03).

CONCLUSION

In healthy young participants, plasma lipid responses to PO and CB, enriched in SFA but having primarily unsaturated fatty acid in the sn-2 position of TAG, did not differ from OO.

The Effect of Coconut Oil Consumption on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Clinical Trials

BACKGROUND

Coconut oil is high in saturated fat and may, therefore, raise serum cholesterol concentrations, but beneficial effects on other cardiovascular risk factors have also been suggested. Therefore, we conducted a systematic review of the effect of coconut oil consumption on blood lipids and other cardiovascular risk factors compared with other cooking oils using data from clinical trials.

METHODS

We searched PubMed, SCOPUS, Cochrane Registry, and Web of Science through June 2019. We selected trials that compared the effects of coconut oil consumption with other fats that lasted at least 2 weeks. Two reviewers independently screened articles, extracted data, and assessed the study quality according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The main outcomes included low-density lipoprotein cholesterol (LDL-cholesterol), high-density lipoprotein cholesterol (HDL-cholesterol), total cholesterol, triglycerides, measures of body fatness, markers of inflammation, and glycemia. Data were pooled using random-effects meta-analysis.

RESULTS

16 articles were included in the meta-analysis. Results were available from all trials on blood lipids, 8 trials on body weight, 5 trials on percentage body fat, 4 trials on waist circumference, 4 trials on fasting plasma glucose, and 5 trials on C-reactive protein. Coconut oil consumption significantly increased LDL-cholesterol by 10.47 mg/dL (95% CI: 3.01, 17.94; I² = 84%, N=16) and HDL-cholesterol by 4.00 mg/dL (95% CI: 2.26, 5.73; I² = 72%, N=16) as compared with nontropical vegetable oils. These effects remained significant after excluding nonrandomized trials, or trials of poor quality (Jadad score <3). Coconut oil consumption did not significantly affect markers of glycemia, inflammation, and adiposity as compared with nontropical vegetable oils.

CONCLUSIONS

Coconut oil consumption results in significantly higher LDL-cholesterol than nontropical vegetable oils. This should inform choices about coconut oil consumption.

Intake of Palm Olein and Lipid Status in Healthy Adults: A Meta-Analysis

It is not clear whether a saturated fatty acid-rich palm olein diet has any significant adverse effect on established surrogate lipid markers of cardiovascular disease (CVD) risk. We reviewed the effect of palm olein with other oils on serum lipid in healthy adults. We searched in MEDLINE and CENTRAL: Central Register of Controlled Trials from 1975 to January 2018 for randomized controlled trials of ≥2 wk intervention that compared the effects of palm olein (the liquid fraction of palm oil) with other oils such as coconut oil, lard, canola oil, high-oleic sunflower oil, olive oil, peanut oil, and soybean oil on changes in serum lipids. Nine studies were eligible and were included, with a total of 533 and 542 subjects on palm olein and other dietary oil diets, respectively. We extracted and compared all the data for serum lipids, such as total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglyceride, and TC/HDL cholesterol ratio. When comparing palm olein with other dietary oils, the overall weighted mean differences for TC, LDL cholesterol, HDL cholesterol, triglycerides, and the TC/HDL cholesterol ratio were -0.10 (95% CI: -0.30, 0.10; P = 0.34), -0.06 (95% CI: -0.29,0.16; P = 0.59), 0.02 (95% CI: -0.01, 0.04; P = 0.20), 0.01 (95% CI: -0.05, 0.06; P = 0.85), and -0.15 (95% CI: -0.43, 0.14; P = 0.32), respectively. Overall, there are no significant differences in the effects of palm olein intake on lipoprotein biomarkers (P > 0.05) compared with other dietary oils. However, dietary palm olein was found to have effects comparable to those of other unsaturated dietary oils (monounsaturated fatty acid- and polyunsaturated fatty acid-rich oils) but differed from that of saturated fatty acid-rich oils with respect to the serum lipid profile in healthy adults.

Cholesterolaemic Effects of the Saturated Fatty Acids of Palm Oil

Dietary saturated fats are implicated as a major risk factor in hypercholesterolaemia and cardiovascular disease. Palm oil is a major source of the world's supply of oils and fats, but because of its relatively high content of saturated fatty acids (principally palmitic acid), its consumption has come under intense scrutiny over the last decade owing to potential health implications. Based on studies carried out more than thirty years ago, the hypothesis was developed that lauric, myristic, and palmitic acid were the three principal cholesterol-raising saturated fatty acids. Since palmitic acid is the most abundant fatty acid in the diet, the cholesterol-raising effect of all saturated fatty acids was accordingly assigned to it. However, recent studies from both humans and experimental animals suggest that not all saturated fatty acids are cholesterol-raising. When all dietary fatty acids are equalized, with the exception of the two being tested, palmitic acid appears to have no impact on the plasma cholesterol in normocholesterolaemic subjects when dietary cholesterol intake is below a certain critical level (400 mg per day). Only when cholesterol consumption exceeds this level, or when hypercholesterolaemic subjects are studied, does palmitic acid appear to increase the plasma cholesterol. These differential effects of palmitic acid on plasma cholesterol are thought to reflect differences in LDL-receptor status. Collectively these data imply that, for most of the world's population, palm oil would be an inexpensive and readily metabolized source of dietary energy with minimal impact on cholesterol metabolism.

A Critical Review of the Cholesterolaemic Effects of Palm Oil

This paper reviews recent reports of the cholesterolaemic effects of palm oil. The evidence indicates that the substitution of palm oil or its lipid fractions for the usual fats in the diet does not result in an elevation of total serum cholesterol in lean, normocholesterolaemic individuals with a cholesterol intake of less than 300 mg per day. When threshold dietary levels of linoleic acid (18:2) are met, they tend to counter the cholesterol-raising effects of the 12- and 16-carbon saturated fatty acids. In view of this, the use of a cholesterol saturated-fat index to measure the hypercholesterolaemic and atherogenic potential of foods can be misleading, particularly when applied to palm oil. Nutritionists and health professionals need to keep abreast of recent knowledge on the cholesterolaemic impact of dietary fats and fatty acids.

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.

Effects of oils and solid fats on blood lipids: a systematic review and network meta-analysis

The aim of this network meta-analysis (NMA) is to compare the effects of different oils/solid fats on blood lipids. Literature searches were performed until March 2018. Inclusion criteria were as follows: i) randomized trial (≥3 weeks study length) comparing at least two of the following oils/solid fats: safflower, sunflower, rapeseed, hempseed, flaxseed, corn, olive, soybean, palm, and coconut oil, and lard, beef-fat, and butter; ii) outcomes LDL-cholesterol (LDL-C), total cholesterol (TC), HDL-cholesterol (HDL-C), and triacylglycerols (TGs). A random dose-response (per 10% isocaloric exchange) NMA was performed and surface under the cumulative ranking curve (SUCRA) was estimated. Fifty-four trials were included in the NMA. Safflower oil had the highest SUCRA value for LDL-C (82%) and TC (90%), followed by rapeseed oil (76% for LDL-C, 85% for TC); whereas, palm oil (74%) had the highest SUCRA value for TG, and coconut oil (88%) for HDL-C. Safflower, sunflower, rapeseed, flaxseed, corn, olive, soybean, palm, and coconut oil as well beef fat were more effective in reducing LDL-C (−0.42 to −0.23 mmol/l) as compared with butter. Despite limitations in these data, our NMA findings are in line with existing evidence on the metabolic effects of fat and support current recommendations to replace high saturated-fat food with unsaturated oils.

Effects of coconut oil consumption on energy metabolism, cardiometabolic risk markers, and appetitive responses in women with excess body fat

PURPOSE

Virgin coconut oil (VCO) is a medium-chain fatty acid source with popularly attributed benefits on obesity management. However, its role on obesity requires elucidation due to its saturated nature. In the study herein, we investigated acute effects of VCO consumption on energy metabolism, cardiometabolic risk markers, and appetitive responses in women with excess body fat.

METHODS

Fifteen adult women with excess body fat (37.43 ± 0.83%) participated in this randomized, crossover, controlled study. Two isocaloric mixed breakfasts containing 25 mL of VCO or control (extra-virgin olive oil-C) were evaluated. Resting energy expenditure (REE), fat oxidation rate (FOR), diet induced thermogenesis (DIT) and appetitive subjective responses were assessed at fasting and postprandial periods (up to 240 min). Cardiometabolic risk markers were assessed at fasting and up to 180 min postprandially.

RESULTS

VCO did not affect REE, FOR, and DIT compared to C. In addition, VCO did not cause deleterious change in triglycerides, total cholesterol, HDL-c, LDL-c, triglycerides/HDL-c ratio, uric acid, glucose and Homeostasis Model Assessment of Insulin Resistance Index (HOMA-IR) (P _{time×treatment} > 0.05). However, VCO suppressed less hunger (P _{time×treatment} = 0.003), total satiety (P _iAUC = 0.021) and total fullness (P _iAUC = 0.035) responses than C.

CONCLUSIONS

VCO consumption did not acutely change energy metabolism and cardiometabolic risk markers when added to a mixed breakfast but promoted less appetitive responses.

Comparing effects of soybean oil- and palm olein-based mayonnaise consumption on the plasma lipid and lipoprotein profiles in human subjects: a double-blind randomized controlled trial with cross-over design

BACKGROUND

Mayonnaise is used widely in contemporary human diet with widespread use as a salad dressing or spread on breads. Vegetable oils used in its formulation may be a rich source of ω-6 PUFAs and the higher-PUFA content of mayonnaise may be beneficial in mediating a hypocholesterolemic effect. This study, therefore, evaluated the functionality of mayonnaise on cardiometabolic risk within a regular human consumption scenario.

METHODS

Subjects underwent a randomized double-blind crossover trial, consuming diets supplemented with 20 g/day of either soybean oil-based mayonnaise (SB-mayo) or palm olein-based mayonnaise (PO-mayo) for 4 weeks each with a 2-week wash-out period. The magnitude of changes for metabolic outcomes between dietary treatments was compared with PO-mayo serving as the control. The data was analyzed by ANCOVA using the GLM model. Analysis was adjusted for weight changes.

RESULTS

Treatments resulted in significant reductions in TC (diff = -0.25 mmol/L; P = 0.001), LDL-C (diff = -0.17 mmol/L; P = 0.016) and HDL-C (diff = -0.12 mmol/L; P < 0.001) in SB-mayo compared to PO-mayo without affecting LDL-C:HDL-C ratio (P > 0.05). Lipoprotein particle change was significant with large LDL particles increasing after PO-mayo (diff = +63.2 nmol/L; P = 0.007) compared to SB-mayo but small LDL particles remained unaffected. Plasma glucose, apolipoproteins and oxidative stress markers remained unchanged.

CONCLUSIONS

Daily use with 20 g of linoleic acid-rich SB-mayo elicited reductions in TC and LDL-C concentrations without significantly changing LDL-C:HDL-C ratio or small LDL particle distributions compared to the PO-mayo diet.

TRIAL REGISTRATION

This clinical trial was retrospectively registered with the National Medical Research Register, National Institute of Health, Ministry of Health Malaysia, (NMRR-15-40-24035; registered on 29/01/2015; https://www.nmrr.gov.my/fwbPage.jsp?fwbPageId=ResearchISRForm&fwbAction=Update&fwbStep=10&pk.researchID=24035&fwbVMenu=3&fwbResearchAction=Update ). Ethical approval was obtained from the National University of Malaysia's Medical Ethics Committee (UKM 1.5.3.5/244/SPP/NN-054-2011, approved on 25/05/2011).

A systematic review of high-oleic vegetable oil substitutions for other fats and oils on cardiovascular disease risk factors: implications for novel high-oleic soybean oils

High-oleic acid soybean oil (H-OSBO) is a trait-enhanced vegetable oil containing >70% oleic acid. Developed as an alternative for trans-FA (TFA)-containing vegetable oils, H-OSBO is predicted to replace large amounts of soybean oil in the US diet. However, there is little evidence concerning the effects of H-OSBO on coronary heart disease (CHD)(6) risk factors and CHD risk. We examined and quantified the effects of substituting high-oleic acid (HO) oils for fats and oils rich in saturated FAs (SFAs), TFAs, or n-6 (ω-6) polyunsaturated FAs (PUFAs) on blood lipids in controlled clinical trials. Searches of online databases through June 2014 were used to select studies that defined subject characteristics; described control and intervention diets; substituted HO oils compositionally similar to H-OSBO (i.e., ≥70% oleic acid) for equivalent amounts of oils high in SFAs, TFAs, or n-6 PUFAs for ≥3 wk; and reported changes in blood lipids. Studies that replaced saturated fats or oils with HO oils showed significant reductions in total cholesterol (TC), LDL cholesterol, and apolipoprotein B (apoB) (P < 0.05; mean percentage of change: -8.0%, -10.9%, -7.9%, respectively), whereas most showed no changes in HDL cholesterol, triglycerides (TGs), the ratio of TC to HDL cholesterol (TC:HDL cholesterol), and apolipoprotein A-1 (apoA-1). Replacing TFA-containing oil sources with HO oils showed significant reductions in TC, LDL cholesterol, apoB, TGs, TC:HDL cholesterol and increased HDL cholesterol and apoA-1 (mean percentage of change: -5.7%, -9.2%, -7.3%, -11.7%, -12.1%, 5.6%, 3.7%, respectively; P < 0.05). In most studies that replaced oils high in n-6 PUFAs with equivalent amounts of HO oils, TC, LDL cholesterol, TGs, HDL cholesterol, apoA-1, and TC:HDL cholesterol did not change. These findings suggest that replacing fats and oils high in SFAs or TFAs with either H-OSBO or oils high in n-6 PUFAs would have favorable and comparable effects on plasma lipid risk factors and overall CHD risk.

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.

Palm oil and the heart: A review

Palm oil consumption and its effects on serum lipid levels and cardiovascular disease in humans is still a subject of debate. Advocacy groups with varying agenda fuel the controversy. This update intends to identify evidence-based evaluations of the influence of palm oil on serum lipid profile and cardiovascular disease. Furthermore, it suggests a direction for future research. The sources of information were based on a PubMed, Google Scholar, African Journal online and Medline search using key words including: palm oil, palmitic acid, saturated fatty acids and heart disease. Published animal and human experiments on the association of palm oil and its constituents on the serum lipid profile and cardiovascular disease were also explored for relevant information. These papers are reviewed and the available evidence is discussed. Most of the information in mainstream literature is targeted at consumers and food companies with a view to discourage the consumption of palm oil. The main argument against the use of palm oil as an edible oil is the fact that it contains palmitic acid, which is a saturated fatty acid and by extrapolation should give rise to elevated total cholesterol and low-density lipoprotein cholesterol levels. However, there are many scientific studies, both in animals and humans that clearly show that palm oil consumption does not give rise to elevated serum cholesterol levels and that palm oil is not atherogenic. Apart from palmitic acid, palm oil consists of oleic and linoleic acids which are monounsaturated and polyunsaturated respectively. Palm oil also consists of vitamins A and E, which are powerful antioxidants. Palm oil has been scientifically shown to protect the heart and blood vessels from plaques and ischemic injuries. Palm oil consumed as a dietary fat as a part of a healthy balanced diet does not have incremental risk for cardiovascular disease. Little or no additional benefit will be obtained by replacing it with other oils rich in mono or polyunsaturated fatty acids.

Research advancements in palm oil nutrition

Palm oil is the major oil produced, with annual world production in excess of 50 million tonnes. About 85% of global palm oil produced is used in food applications. Over the past three decades, research on nutritional benefits of palm oil have demonstrated the nutritional adequacy of palm oil and its products, and have resulted in transitions in the understanding these attributes. Numerous studies have demonstrated that palm oil was similar to unsaturated oils with regards to effects on blood lipids. Palm oil provides a healthy alternative to trans-fatty acid containing hydrogenated fats that have been demonstrated to have serious deleterious effects on health. The similar effects of palm oil on blood lipids, comparable to other vegetable oils could very well be due to the structure of the major triglycerides in palm oil, which has an unsaturated fatty acid in the stereospecific numbers (sn)-2 position of the glycerol backbone. In addition, palm oil is well endowed with a bouquet of phytonutrients beneficial to health, such as tocotrienols, carotenoids, and phytosterols. This review will provide an overview of studies that have established palm oil as a balanced and nutritious oil.

Serum lipoprotein composition and vitamin D metabolite levels in clinically isolated syndromes: Results from a multi-center study

CONTEXT

High serum cholesterol is adversely associated with clinical and imaging disease progression outcomes in multiple sclerosis (MS) and in clinically isolated syndrome (CIS), the earliest stage of MS. Low vitamin D levels are associated with an increased risk of disease progression.

OBJECTIVES

To investigate the mechanisms mediating the adverse effects of cholesterol in CIS and to determine the role of the nexus between the vitamin D3 (D3) and cholesterol pathways.

DESIGN

Multi-center, prospective, longitudinal prospective study.

SETTING

University hospital multiple sclerosis centers.

INTERVENTION

Serum samples were obtained prior to any treatment from study subjects.

METHODS

Serum obtained prior to any treatment from 172 CIS patients enrolled in a multi-center, prospective, longitudinal study (119 females: 53 males, age: 28.1 ± SD 8.1 years) were analyzed for high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein AI (ApoAI), ApoAII, ApoB, ApoE, and lipoprotein-a. Levels of 25-hydroxy vitamin D3 (25(OH)D3), 1,25-dihydroxy D3, and 24,25-dihydroxy D3 were measured using liquid chromatography-mass spectrometry.

RESULTS

Greater levels of HDL-C biomarkers (e.g., HDL-C itself, ApoAI, ApoAII and paroxonase arylesterase activity) and LDL-C biomarkers (e.g., LDL-C itself, Apo B) were associated with greater 25(OH)D3. The effects of HDL-C biomarkers were stronger than those of LDL-C. Free cholesterol and cholesteryl ester levels were positively associated with higher 25(OH)D3 levels. Cholesterol palmitate was particularly potent. The nexus between the D3 and cholesterol pathways was proximal to, or in linkage disequilibrium with, 7-dehydrocholesterol reductase DHCR7 rs1790349, endothelial lipase LIPG rs4939883 and proprotein convertase subtilisin/kexin type 9 PCSK9 rs11206510.

CONCLUSIONS

The associations between cholesterol biomarkers and vitamin D metabolite levels in CIS are consistent with the biochemical inter-dependence between the two pathways. Cholesterol biomarkers should be considered for inclusion as covariates when assessing vitamin D levels in CIS.

Palm oil and blood lipid-related markers of cardiovascular disease: a systematic review and meta-analysis of dietary intervention trials

BACKGROUND

Palm oil (PO) may be an unhealthy fat because of its high saturated fatty acid content.

OBJECTIVE

The objective was to assess the effect of substituting PO for other primary dietary fats on blood lipid-related markers of coronary heart disease (CHD) and cardiovascular disease (CVD).

DESIGN

We performed a systematic review and meta-analysis of dietary intervention trials. Studies were eligible if they included original data comparing PO-rich diets with other fat-rich diets and analyzed at least one of the following CHD/CVD biomarkers: total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, TC/HDL cholesterol, LDL cholesterol/HDL cholesterol, triacylglycerols, apolipoprotein A-I and B, very-low-density lipoprotein cholesterol, and lipoprotein(a).

RESULTS

Fifty-one studies were included. Intervention times ranged from 2 to 16 wk, and different fat substitutions ranged from 4% to 43%. Comparison of PO diets with diets rich in stearic acid, monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) showed significantly higher TC, LDL cholesterol, apolipoprotein B, HDL cholesterol, and apolipoprotein A-I, whereas most of the same biomarkers were significantly lower when compared with diets rich in myristic/lauric acid. Comparison of PO-rich diets with diets rich in trans fatty acids showed significantly higher concentrations of HDL cholesterol and apolipoprotein A-I and significantly lower apolipoprotein B, triacylglycerols, and TC/HDL cholesterol. Stratified and meta-regression analyses showed that the higher concentrations of TC and LDL cholesterol, when PO was substituted for MUFAs and PUFAs, were not significant in young people and in subjects with diets with a lower percentage of energy from fat.

CONCLUSIONS

Both favorable and unfavorable changes in CHD/CVD risk markers occurred when PO was substituted for the primary dietary fats, whereas only favorable changes occurred when PO was substituted for trans fatty acids. Additional studies are needed to provide guidance for policymaking.

Nutritional profile of phytococktail from trans-Himalayan plants

We estimated the nutritive value, vitamin content, amino acid composition, fatty acid content, and mineral profile of a phytococktail comprising sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca), and roseroot (Rhodiola imbricata) from trans-Himalaya. The free vitamin forms in the phytococktail were determined by rapid resolution liquid chromatography/tandem mass spectrometry (RRLC-MS/MS). Vitamin E and B-complex vitamins were detected as the principle vitamins. Reversed-phase high performance liquid chromatography (RP-HPLC) with pre-column derivatization was used for identification and quantification of amino acids. Eight essential and eleven non-essential amino acids were quantified, and the content ranged between 76.33 and 9485.67 µg/g. Among the essential amino acids, L-methionine, L-phenylalanine, L-lysine, L-leucine, and L-histidine were found to be the dominant contributors. We also quantified the fatty acids in the phytococktail by using gas chromatography coupled with a flame ionization detector (GC-FID) with fatty acid methyl esters (FAMEs) derivatization. The analysis revealed the presence of 4 major fatty acids contributing to the total lipid content. Palmitic acid was found to be the rich source of saturated fatty acid (SFA) and constituted ∼31% of the total lipid content. Among the unsaturated fatty acids (UFAs), palmitoleic acid (43.47%), oleic acid (20.89%), and linoleic acid (4.31%) were prominent. The mineral profiling was carried out by inductively coupled plasma optical emission spectrometer (ICP-OES), and it was found to contain a number of important dietary mineral elements. The harsh climatic conditions, difficult terrain, and logistic constraints at high altitude regions of Indian trans-Himalayan cold desert lead to the scarcity of fresh fruits and vegetables. Therefore, the source of multiple vitamins, essential amino acids, fatty acids, and dietary minerals from the phytococktail would provide great health benefit in the stressful environment and could be used as a high value nutritional supplement.

Reappraisal of SFA and cardiovascular risk

This review reappraises dietary advice to reduce and replace SFA for the prevention of CVD. In the 1970s, SFA accounted for about 18% UK food energy, by 2001 it had fallen to 13% and continues to be above the <11% target. Compared with carbohydrates, C12–C16 SFA raise serum total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) without affecting the TC:HDL-C ratio; other SFA have neutral effects on the fasting lipid profile. Replacing 3% dietary SFA with MUFA or PUFA lowers LDL-C by 2% and TC:HDL-C ratio by 0·03. No other specific adverse effects of SFA compared with MUFA on risk CVD factors have been proven. Meta-analyses of prospective cohort studies report the relative risks (95% CI) of high v. low intakes of SFA to be 1·07 (0·96, 1·19) for CHD, 0·81 (0·62, 1·05) for stroke and 1·00 (0·89, 1·11) for CVD mortality and were not statistically significant. Exchanging 5% energy SFA for PUFA or carbohydrates found hazard ratios (95% CI) for CHD death to be 26% (−23, −3) and 4% (−18, 12; NS) lower, respectively. Meta-analysis of randomised controlled trials with clinical endpoints reports mean reductions (95% CI) of 14% (4, 23) in CHD incidence and 6% (−25, 4; NS) in mortality in trials, where SFA was lowered by decreasing and/or modifying dietary fat. In conclusion, SFA intakes are now close to guideline amounts and further reductions may only have a minor impact on CVD.

Dietary fats and health: dietary recommendations in the context of scientific evidence

Although early studies showed that saturated fat diets with very low levels of PUFAs increase serum cholesterol, whereas other studies showed high serum cholesterol increased the risk of coronary artery disease (CAD), the evidence of dietary saturated fats increasing CAD or causing premature death was weak. Over the years, data revealed that dietary saturated fatty acids (SFAs) are not associated with CAD and other adverse health effects or at worst are weakly associated in some analyses when other contributing factors may be overlooked. Several recent analyses indicate that SFAs, particularly in dairy products and coconut oil, can improve health. The evidence of ω6 polyunsaturated fatty acids (PUFAs) promoting inflammation and augmenting many diseases continues to grow, whereas ω3 PUFAs seem to counter these adverse effects. The replacement of saturated fats in the diet with carbohydrates, especially sugars, has resulted in increased obesity and its associated health complications. Well-established mechanisms have been proposed for the adverse health effects of some alternative or replacement nutrients, such as simple carbohydrates and PUFAs. The focus on dietary manipulation of serum cholesterol may be moot in view of numerous other factors that increase the risk of heart disease. The adverse health effects that have been associated with saturated fats in the past are most likely due to factors other than SFAs, which are discussed here. This review calls for a rational reevaluation of existing dietary recommendations that focus on minimizing dietary SFAs, for which mechanisms for adverse health effects are lacking.

Diets high in palmitic acid (16:0), lauric and myristic acids (12:0 + 14:0), or oleic acid (18:1) do not alter postprandial or fasting plasma homocysteine and inflammatory markers in healthy Malaysian adults

BACKGROUND

Dietary fat type is known to modulate the plasma lipid profile, but its effects on plasma homocysteine and inflammatory markers are unclear.

OBJECTIVE

We investigated the effects of high-protein Malaysian diets prepared with palm olein, coconut oil (CO), or virgin olive oil on plasma homocysteine and selected markers of inflammation and cardiovascular disease (CVD) in healthy adults.

DESIGN

A randomized-crossover intervention with 3 dietary sequences of 5 wk each was conducted in 45 healthy subjects. The 3 test fats, namely palmitic acid (16:0)-rich palm olein (PO), lauric and myristic acid (12:0 + 14:0)-rich CO, and oleic acid (18:1)-rich virgin olive oil (OO), were incorporated at two-thirds of 30% fat calories into high-protein Malaysian diets.

RESULTS

No significant differences were observed in the effects of the 3 diets on plasma total homocysteine (tHcy) and the inflammatory markers TNF-α, IL-1β, IL-6, and IL-8, high-sensitivity C-reactive protein, and interferon-γ. Diets prepared with PO and OO had comparable nonhypercholesterolemic effects; the postprandial total cholesterol for both diets and all fasting lipid indexes for the OO diet were significantly lower (P < 0.05) than for the CO diet. Unlike the PO and OO diets, the CO diet was shown to decrease postprandial lipoprotein(a).

CONCLUSION

Diets that were rich in saturated fatty acids prepared with either PO or CO, and an OO diet that was high in oleic acid, did not alter postprandial or fasting plasma concentrations of tHcy and selected inflammatory markers. This trial was registered at clinicaltrials.gov as NCT00941837.

Palm olein increases plasma cholesterol moderately compared with olive oil in healthy individuals

BACKGROUND

Despite the high content of palmitic acid, palm olein has been shown to have a neutral effect on plasma cholesterol concentrations when compared with olive oil, which is suggested to be attributable to palmitic acid in the sn-1 and sn-3 position. In contrast, palmitic acid is in the sn-2 position in lard.

OBJECTIVE

The objective was to investigate the effects of a diet rich in palm olein, fractionated palm oil, olive oil, and lard on plasma blood lipids, inflammatory markers, glucose, and insulin.

DESIGN

A controlled double-blinded, randomized 3 × 3 wk crossover dietary intervention study included 32 healthy men who daily replaced part of their habitual dietary fat intake with ~ 17% of energy from palm olein, olive oil, or lard, respectively.

RESULTS

Compared with intake of olive oil, palm olein and lard increased total cholesterol and LDL cholesterol (P < 0.0001). Palm olein resulted in a lower plasma triacylglycerol concentration than did olive oil (P < 0.01). No difference in effects was observed in plasma HDL-cholesterol, high-sensitivity C-reactive protein, plasminogen activator-1, insulin, and glucose concentrations.

CONCLUSIONS

The current study did not support the previous finding that the effect of palm olein on total plasma cholesterol and LDL cholesterol in healthy individuals with normal plasma cholesterol concentrations is neutral compared with that of olive oil. Thus, sn-positioning was not confirmed to be important with regard to the effect on plasma cholesterol. The relatively lower plasma triacylglycerol concentration after the palm olein diet than after the olive oil diet was unexpected. This trial is registered at clinicaltrials.gov as NCT00743301.

Chemical Characterization of the Lipophilic Fraction of Livistona Decipiens and Livistona Chinensis Fruit Pulps (Palmae) and Assessment of Their Anti-hyperlipidemic and Anti-ulcer Activities

The oil of the dried pulps of Livistona decipiens and L. chinensis palm fruits have been studied for the first time by gas chromatography-mass spectrometry for their unsaponifiable matter (USM) and fatty acid composition (FAME). The anti-hyperlipidemic and anti-ulcer activities for both oils were also assayed. The principal fatty acid of L. decipiens pulp oil was oleic acid (53.4 %) and of L. chinensis pulp oil palmitic acid (47.4 %). In relation to anti-hyperlipidemic properties, the pulp oil of L. decipiens presented a better profile than that of L. chinensis, in comparison with the reference standard (simvastatin). In addition, both pulp oils showed high anti-ulcer activity using an indomethacin-induced ulceration technique in rat stomach. The relationship between the anti-hyperlipidemic, anti-ulcer and chemical composition of the pulp oils is also discussed.

Cholesterolaemic influence of palmitic acid in thesn-1, 3v.thesn-2 position with high or low dietary linoleic acid in healthy young men

Healthy young men were fed four diets for 2 weeks each providing natural fats containing palmitic acid (16 : 0) predominantly in thesn-1, 3 position of dietary TAG or containing 16 : 0 predominantly in thesn-2 position with low or high levels of linoleic acid (18 : 2n-6). Two treatments supplied 16 : 0 in thesn-1, 3 positions from palmstearin with low (3 % energy) or high (>7 % energy) 18 : 2n-6 and two treatments supplied 16 : 0 in thesn-2 position from lard with high or low levels of 18 : 2n-6. Diets contained 30–35 % energy as fat, 7–11 % energy as 16 : 0 and moderate levels of cholesterol. Fasting serum cholesterol and lipoprotein concentrations were measured. Cholesterol fractional synthesis rate (FSR) was determined by2H incorporation. Diets providing 16 : 0 in thesn-2 position resulted in lower fasting serum total cholesterol (TC) and a lower TC:HDL ratio than diets providing 16 : 0 in thesn-1, 3 positions. Diets with high levels of 18 : 2n-6 significantly decreased the TC:HDL ratio, reaffirming the well-known cholesterol-reducing effect of 18 : 2n-6. A lower non-esterified cholesterol FSR was observed with low dietary levels of 18 : 2n-6. No differences between dietary treatments were found for serum HDL-cholesterol, LDL-cholesterol or TAG. It is concluded that dietary fats containing 16 : 0 in thesn-2 position may result in slightly lower fasting TC than diets providing 16 : 0 in thesn-1, 3 positions, while the level ofn-6 polyunsaturated fat influences endogenous cholesterol synthesis.