Influence of a stearic acid-rich structured triacylglycerol on postprandial lipemia, factor VII concentrations, and fibrinolytic activity in healthy subjects

Chemical Characterisation of New Oils Extracted from Cañihua and Tarwi Seeds with Different Organic Solvents

Vegetable oils are rich in health-beneficial compounds, including fatty acids, phenolic compounds, natural antioxidants, and fat-soluble vitamins. However, oil extraction methods can influence their composition. This study aims to understand the chemical basis for developing a green process to extract oils from two Andean seeds, cañihua (Chenopodium pallidicaule) and tarwi (Lupinus mutabilis). Ethanol, considered a green solvent, is compared to petroleum ether used at the laboratory level and hexane used at the industrial scale for extracting oils. The extraction efficiency is assessed in terms of yield, fatty acids profile, polar and neutral lipids, tocopherols, phenolic compounds, and antioxidant capacity. The chemical composition of edible commercial oils, such as sunflower, rapeseed, and olive oils, was used as a reference. Hexane had the highest extraction yield, followed by petroleum ether and ethanol. However, the oils extracted with ethanol having yields of tarwi 15.5% and cañihua 5.8%, w/w showed the significatively superior content of tocopherols (α, γ, and δ); phenolic compounds; and antioxidant capacity. In addition, ethanol-extracted (EE) oils have higher levels of polar lipids, such as phosphatidylcholine and phosphatidylinositol, than those extracted with the other solvents. Remarkably, EE oils presented comparable or slightly higher levels of monounsaturated fatty acids than those extracted with hexane. Finally, compared to the commercial oils, tarwi and cañihua EE oils showed lower but acceptable levels of oleic, linoleic and palmitic acids and a wider variety of fatty acids (10 and 13, respectively). The composition of tarwi and cañahua oils extracted with ethanol includes compounds associated with nutritional and health benefits, providing a sustainable alternative for oil production.

Plasma Phospholipid Fatty Acids and Risk of Venous Thromboembolism: Mendelian Randomization Investigation

Circulating fatty acids may affect thrombosis but epidemiological data on the associations between fatty acids and risk of venous thromboembolism (VTE) are limited and conflicting. We conducted a Mendelian randomization study to examine the causal associations of 10 circulating fatty acids with VTE risk. Genetic variants strongly associated with ten fatty acids and without linkage disequilibrium were selected as instrumental variables from the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Genetic associations for VTE and its subtypes were obtained from the International Network Against Venous Thrombosis Consortium (30,234 cases and 172,122 controls) and the FinnGen study (11,288 VTE cases and 254,771 controls). Estimates from the two data sources were combined. Per standard deviation increase in genetically predicted fatty acid levels, the combined odds ratio (OR) of VTE was 0.88 (95% confidence interval [CI] 0.84–0.92) for α-linolenic acid, 0.92 (95% CI 0.90–0.95) for linoleic acid, 0.85 (95% CI 0.78–0.92) for palmitoleic acid, 0.77 (95% CI 0.77–0.84) for oleic acid, 1.16 (95% CI 1.10–1.23) for eicosapentaenoic acid, 1.10 (95% CI 1.06–1.14) for docosapentaenoic acid, 1.06 (95% CI 1.04–1.08) for arachidonic acid, and 1.19 (95% CI 1.11–1.28) for stearic acid. Genetically predicted levels of docosahexaenoic acid or palmitoleic acid were not associated with VTE risk. Four and eight out of ten genetically predicted fatty acid levels were associated with risk of pulmonary embolism and deep vein thrombosis, respectively. This study suggests that strategies targeting at fatty acids may act as prevention approaches for VTE.

Who would benefit most from postprandial lipid screening?

BACKGROUND & AIMS

Individuals with fasting triglycerides (TG) <150 mg/dL can experience a deleterious postprandial TG response ≥220 mg/dL to a high-fat meal (HFM). The purpose of this study was to identify individuals based on fasting TG that would benefit most from additional postprandial screening.

METHODS

We conducted a secondary analysis of 7 studies from our laboratories featuring 156 disease-free participants (64 M, 92 F; age 18-70 years; BMI 18.5-30 kg/m2). Participants observed a 10-12 h overnight fast, after which they consumed an HFM (10-13 kcal/kg body mass; 61-64% kcal from fat). Two methods were used to identify lower and upper fasting TG cut points. Method 1 identified the lower limit as the TG concentration at which ≥90% of individuals presented peak postprandial TG (PPTG) <220 mg/dL and the upper limit as the concentration which ≥90% of individuals presented PPTG ≥220 mg/dL. Method 2 utilized receiver operating characteristic (ROC) curves and identified the lower limit as the fasting TG concentration where sensitivity was ≈95% and the upper limit as the concentration at which specificity was ≈95%.

RESULTS

In Method 1, 90% of individuals with fasting TG >130 mg/dL (>1.50 mmol/L) exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L), while 100% of individuals with fasting TG <66 mg/dL (0.75 mmol/L) had PPTG that did not exceed 220 mg/dL (2.50 mmol/L). In Method 2, when sensitivity was ≈95%, the corresponding fasting TG concentration was 70 mg/dL (0.79 mmol/L). When specificity was ≈95%, the corresponding fasting TG concentration was 114 mg/dL (1.29 mmol/L). Based on methods 1 and 2, there was a moderate positive association (r = 0.37, p < 0.004) between fasting and PPTG for individuals with fasting TG between 70 and 130 mg/dL (0.79-1.50 mmol/L), in which 24% exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L) while 76% did not.

CONCLUSIONS

Postprandial TG testing is likely most useful for individuals with fasting TG concentrations between 70 and 130 mg/dL (0.79-1.50 mmol/L). Outside of this range, postprandial TG responses are largely predictable. Establishing a specific patient group for which postprandial TG testing is most useful may lead to earlier risk detection in these individuals.

The Impact of Dietary Glycemic Index and Glycemic Load on Postprandial Lipid Kinetics, Dyslipidemia and Cardiovascular Risk

Many recent studies have acknowledged postprandial hypetriglyceridemia as a distinct risk factor for cardiovascular disease. This dysmetabolic state is the result of the hepatic overproduction of very low-density lipoproteins (VLDLs) and intestinal secretion of chylomicrons (CMs), which leads to highly atherogenic particles and endothelial inflammation. Postprandial lipid metabolism does not only depend on consumed fat but also on the other classes of nutrients that a meal contains. Various mechanisms through which carbohydrates exacerbate lipidemia have been identified, especially for fructose, which stimulates de novo lipogenesis. Glycemic index and glycemic load, despite their intrinsic limitations, have been used as markers of the postprandial glucose and insulin response, and their association with metabolic health and cardiovascular events has been extensively studied with contradictory results. This review aims to discuss the importance and pathogenesis of postprandial hypertriglyceridemia and its association with cardiovascular disease. Then, we describe the mechanisms through which carbohydrates influence lipidemia and, through a brief presentation of the available clinical studies on glycemic index/glycemic load, we discuss the association of these indices with atherogenic dyslipidemia and address possible concerns and implications for everyday practice.

The Influence of Different Foods and Food Ingredients on Acute Postprandial Triglyceride Response: A Systematic Literature Review and Meta-Analysis of Randomized Controlled Trials

The use of postprandial triglyceride (ppTG) as a cardiovascular disease risk indicator has gained recent popularity. However, the influence of different foods or food ingredients on the ppTG response has not been comprehensively characterized. A systematic literature review and meta-analysis was conducted to assess the effects of foods or food ingredients on the ppTG response. PubMed, MEDLINE, Cochrane, and CINAHL databases were searched for relevant acute (<24-h) randomized controlled trials published up to September 2018. Based on our selection criteria, 179 relevant trials (366 comparisons) were identified and systematically compiled into distinct food or food ingredient categories. A ppTG-lowering effect was noted for soluble fiber (Hedges' giAUC = -0.72; 95% CI: -1.33, -0.11), sodium bicarbonate mineral water (Hedges' gAUC = -0.42; 95% CI: -0.79, -0.04), diacylglycerol oil (Hedges' giAUC = -0.38; 95% CI: -0.75, -0.00), and whey protein when it was contrasted with other proteins. The fats group showed significant but opposite effects depending on the outcome measure used (Hedges' giAUC = -0.32; 95% CI: -0.61, -0.03; and Hedges' gAUC = 0.16; 95% CI: 0.06, 0.26). Data for other important food groups (nuts, vegetables, and polyphenols) were also assessed but of limited availability. Assessing for oral fat tolerance test (OFTT) recommendation compliance, most trials were ≥4 h long but lacked a sufficiently high fat challenge. iAUC and AUC were more common measures of ppTG. Overall, our analyses indicate that the effects on ppTG by different food groups are diverse, largely influenced by the type of food or food ingredient within the same group. The type of ppTG measurement can also influence the response.

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.

Investigation of the role of α-lipoic acid on fatty acids profile, some minerals (zinc, copper, iron) and antioxidant activity against aluminum-induced oxidative stress in the liver of male rats

BACKGROUND

We have investigated the effects of α-lipoic acid (LA), a powerful antioxidant, on the fatty acid (FA) profiles, aluminum accumulation, antioxidant activity and some minerals such as zinc, copper and iron against aluminum chloride (AlCl3)-induced oxidative stress in rat liver.

METHODS

Twenty-eight male Wistar rats were divided into four groups as control, LA, AlCl3 and LA+AlCl3. For 30 days, LA was intraperitoneally administrated (50 mg/kg) and AlCl3 was given via orogastric gavage (1600 ppm) every other day.

RESULTS

AlCl3-treated animals exhibited higher hepatic malondialdehyde concentration and lower glutathione peroxidase and catalase activity, whereas these alterations were restored by the LA supplementation. Total saturated FA of the AlCl3-treated group was higher than the LA supplementation groups. Moreover, total unsaturated FA level of the LA+AlCl3 group was higher than the AlCl3-treated group. Hepatic zinc level of the AlCl3-treated group was lower than the control group, whereas it was higher in the LA and the LA+AlCl3 groups. Hepatic copper levels did not significantly change in the experimental groups. Iron level was lower in the LA and LA+AlCl3 groups compared with the AlCl3-treated group. Moreover, the liver Al concentration was found to be lower in the LA and LA+AlCl3 groups compared to the AlCl3 group.

CONCLUSIONS

These results indicate that AlCl3 treatment can induce oxidative stress in the liver. LA supplementation has a beneficial effect on the AlCl3-induced alterations such as high lipid peroxidation, Al accumulation, FA profile ratios and mineral concentrations.

Influence of Fasting Status and Sample Preparation on Metabolic Biomarker Measurements in Postmenopausal Women

BACKGROUND

Epidemiologic data linking metabolic markers-such as insulin, insulin-like growth factors (IGFs)-and adipose tissue-derived factors with cancer are inconsistent. Between-study differences in blood collection protocols, in particular participant's fasting status, may influence measurements.

METHODS

We investigated the impact of fasting status and blood sample processing time on components of the insulin/IGF axis and in adipokines in a controlled feeding study of 45 healthy postmenopausal-women aged 50-75 years. Fasting blood samples were drawn (T0), after which subjects ate a standardized breakfast; subsequent blood draws were made at 1 hour (T1), 3 hours (T3), and 6 hours (T6) after breakfast. Serum samples were assayed for insulin, C-peptide, total- and free-IGF-I, IGF-binding protein [BP]-1 and -3, total and high molecular weight (HMW)-adiponectin, retinol binding protein-4, plasminogen activator inhibitor (PAI)-1, and resistin.

RESULTS

Insulin and C-peptide levels followed similar postprandial trajectories; intra-class correlation coefficients [ICC] for insulin = 0.75, (95%CI:0.64-0.97) and C-peptide (ICC = 0.66, 95%CI:0.54-0.77) were similarly correlated in fasting (Spearman correlation, r = 0.78, 95%CI:0.64-0.88) and postprandial states (T1, r = 0.77 (95%CI: 0.62-0.87); T3,r = 0.78 (95%CI: 0.63-0.87); T6,r = 0.77 (95%CI: 0.61-0.87)). Free-IGF-I and IGFBP-1 levels were also affected by fasting status, whereas total-IGF-I and IGFBP-3 levels remained unchanged. Levels of adipokines were largely insensitive to fasting status and blood sample processing delays.

CONCLUSION

Several components of the insulin/IGF axis were significantly impacted by fasting state and in particular, C-peptide levels were substantially altered postprandially and in a similar manner to insulin.

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.

Effect of linagliptin compared with glimepiride on postprandial glucose metabolism, islet cell function and vascular function parameters in patients with type 2 diabetes mellitus receiving ongoing metformin treatment

BACKGROUND

The goal of this study was to investigate the effects of linagliptin compared with glimepiride on alpha and beta cell function and several vascular biomarkers after a standardized test meal.

METHODS

Thirty-nine patients on metformin alone (age, 64 ± 7 years; duration of type 2 diabetes mellitus, 7.8 ± 4.5years, 27 male, 12 female; HbA1c , 57.2 ± 6.9 mmol/mol; mean ± SD) were randomized to receive linagliptin 5 mg (n = 19) or glimepiride (n = 20) for a study duration of 12 weeks. Glucagon-like peptide 1, blood glucose, insulin, intact proinsulin, glucagon, plasminogen activator inhibitor-1 (PAI-1), cyclic guanosinmonophosphat and asymetric dimethylarginin levels were measured in the fasting state and postprandial at 30-min intervals for a duration of 5 h. The areas under the curve (AUC0-300 min ) were calculated for group comparisons.

RESULTS

HbA1c , fasting and postprandial glucose levels improved in both groups. An increase in postprandial insulin (22595 ± 5984 pmol/L*min), postprandial intact proinsulin (1359 ± 658 pmol/L*min), postprandial glucagon (317 ± 1136 pg/mL*min) and postprandial PAI-1 levels (863 ± 467 ng/mL*min) could be observed during treatment with glimepiride, whereas treatment with linagliptin was associated with a decrease in postprandial insulin (-8007 ± 4204 pmol/L*min), intact proinsulin (-1771 ± 426 pmol/L*min), postprandial glucagon (-1597 ± 1831 pg/mL*min) and PAI-1 levels (-410 ± 276 ng/mL*min).

CONCLUSIONS

Despite an improvement in blood glucose control in both groups, linagliptin reduced postprandial insulin, proinsulin, glucagon and PAI-levels. These results indicate an improvement in postprandial alpha and beta cell function, as well as a reduced postprandial vascular risk profile during treatment with linagliptin.

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.

Gastric digestion of raw and roasted almonds in vivo

Almonds are an important dietary source of lipids, protein, and α-tocopherol. It has been demonstrated that the physical form of almond kernels influences their digestion and absorption, but the role of thermal processes on the digestion of almonds has received little attention. The objectives of this study were to examine the gastric emptying and nutrient composition of gastric chyme from pigs (used as a model for the adult human) fed a single meal of either raw or roasted almonds over a 12-h postprandial period (72 pigs total, 6 pigs at each diet-time combination). Concentrations of glucose, triacylglycerols, and α-tocopherol in peripheral plasma during the 12-h postprandial period were determined. For dry matter and lipid, the gastric emptying profile was not different between raw and roasted almonds. Roasting almonds also did not influence gastric pH, or plasma glucose or triacylglycerols levels. In contrast, the gastric emptying of protein was more rapid for raw almonds compared to roasted almonds (P < 0.01) and intragastric protein content exhibited segregation (P < 0.001) throughout the stomach, with raw almonds having a higher level of segregation compared to roasted almonds. Postprandial plasma α-tocopherol levels were, on average 33% greater (P < 0.001) after consumption of raw almonds, most likely as a result of the higher concentration of α-tocopherol in raw almonds compared to roasted almonds. Roasting of almonds did not influence the overall gastric emptying process, but did lead to differences in the distribution of protein in the stomach and to the gastric emptying of protein.

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.

Fatty acids as biocompounds: their role in human metabolism, health and disease: a review. part 2: fatty acid physiological roles and applications in human health and disease

BACKGROUND

This is the second of two review parts aiming at describing the major physiological roles of fatty acids, as well as their applications in specific conditions related to human health.

RESULTS

The review included the current literature published in Pubmed up to March 2011. In humans, fatty acids are a principle energy substrate and structural components of cell membranes (phospholipids) and second messengers. Fatty acids are also ligands of nuclear receptors affecting gene expression. Longer-chain (LC) polyunsaturated fatty acids (PUFA), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid are precursors of lipid mediators such as eicosanoids (prostaglandins, leukotrienes, thromboxanes), resolvins and neuroprotectins. Lipid mediators produced by EPA and DHA (LC n-3 PUFA; mainly found in oily fish) are considered as inflammation-resolving, and thus, fish oil has been characterised as antiinflammatory. Recommendations for EPA plus DHA intake from oily fish vary between 250-450 mg/day. Dietary reference values for fat vary between nutrition bodies, but mainly agree on a low total and saturated fat intake. The existing literature supports the protective effects of LC n-3 PUFA (as opposed to n-6 PUFA and saturated fat) in maternal and offspring health, cardiovascular health, insulin sensitivity, the metabolic syndrome, cancer, critically ill patients, and immune system disorders.

CONCLUSION

Fatty acids are involved in multiple pathways and play a major role in health. Further investigation and a nutrigenomics approach to the effects of these biocompounds on health and disease development are imperative and highlight the importance of environmental modifications on disease outcome.

Fatty acids as biocompounds: their role in human metabolism, health and disease--a review. Part 1: classification, dietary sources and biological functions

BACKGROUND

Fatty acids are substantial components of lipids and cell membranes in the form of phospholipids. This review consists of two parts. The present part aims at describing fatty acid classification, dietary sources and biological functions. The second part will focus on fatty acid physiological roles and applications in human health and disease.

RESULTS

In humans, not all fatty acids can be produced endogenously due to the absence of certain desaturases. Thus, specific fatty acids termed essential (linoleic, alpha-linolenic) need to be taken from the diet. Other fatty acids whose synthesis depends on essential fatty acid intake include eicosapentaenoic acid and docosahexaenoic acid, found in oily fish. Dietary sources of saturated fatty acids are animal products (butter, lard) and tropical plant oils (coconut, palm), whereas sources of unsaturated fatty acids are vegetable oils (such as olive, sunflower, and soybean oils) and marine products (algae and fish oils). Saturated fatty acids have been related to adverse health effects, whereas unsaturated fatty acids, especially monounsaturated and n-3 polyunsaturated, are thought to be protective. In addition, trans fatty acids have been shown to have negative effects on health, whereas conjugated fatty acids might be beneficial. Lastly, fatty acids are the main components of lipid classes (triacylglycerols, phospholipids, cholesteryl esters, non-esterified fatty acids).

CONCLUSION

Fatty acids are important biocompounds which take part in complex metabolic pathways, thus having major biological roles. They are obtained from various dietary sources which determine the type of fat consumed and consequently health outcome.

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

BACKGROUND

The triacylglycerol structure of saturated fats may influence postprandial lipemia.

OBJECTIVE

We tested the hypothesis that high-fat meals rich in palmitic acid (16:0) in the sn-2 position decrease lipemia.

DESIGN

Postprandial changes in plasma lipids, apolipoprotein B48, and cytokines were compared in healthy men (n = 25) and women (n = 25) by using a randomized crossover design after meals that provided 50 g fat supplied as high-oleic sunflower oil (control), palm olein (PO), interesterified palm olein (IPO), and lard containing 0.6, 9.2, 39.1, and 70.5 mol% 16:0, respectively, at sn-2.

RESULTS

The sn-2-rich meals elicited different postprandial responses in plasma concentrations of nonesterified fatty acid (meal × time, P = 0.00014), triacylglycerol (meal × time, P = 0.002), and apolipoprotein B48 (meal × time × sex, P = 0.008). Nonesterified fatty acid concentrations were lower up to 3 h after lard and IPO meals than after control or PO meals. Triacylglycerol increased less steeply after lard and IPO meals than after control and PO meals; the incremental AUCs (iAUCs) were 34% (95% CI: 7%, 124%; P < 0.05) and 26% (95% CI: 16%, 132%; P < 0.05) lower after lard than after control and PO meals, respectively. In men, the maximal increment in apolipoprotein B48 was 14% (95% CI: 3%, 25%; P < 0.05) and 16% (95% CI: 2%, 30%; P < 0.05) lower for lard and IPO, respectively, compared with control. The postprandial iAUC in triacylglycerol was 51% lower in women (P = 0.001) than in men. Plasma IL-6 increased postprandially, but IL-8, TNF-α, and E-selectin decreased after all meals.

CONCLUSION

Fats with a higher proportion of palmitic acid in the sn-2 position decrease postprandial lipemia in healthy subjects. This trial was registered at controlled-trials.com as ISRCTN20774126.

Replacing trans fat: the argument for palm oil with a cautionary note on interesterification

To replace dietary trans fatty acids (TFA), two practical options exist: revert to a natural saturated fat without cholesterol (most likely palm oil or its fractions) or move to a newer model of modified fat hardened by interesterification (IE). This review summarizes the relative risks for cardiovascular disease inherent in these options. Interestingly, both types of fat have been the subject of nutritional scrutiny for approximately the last 40 years, and both have positive and negative attributes. Only during that period has palm oil production developed to the point where it has become the major edible oil in world markets, making clinical studies of it an important objective. On the other hand, approximately 25 human studies have fed interesterified fat in one form or another over this period, some for weeks, some as a single meal. Two types of diet designs exist. Several fed a small amount of interesterified fat, usually incorporated within a margarine, and stayed below the radar of biological detection of any abnormal metabolism. A few fed interesterified fat that incorporated stearic acid, as interesterified 18:0 (IE-18:0), even comparing it to trans fat and saturated fat, as a major part of total daily calories to assess its metabolic impact per se. These latter 5 to 6 studies clearly reveal negative biological effects on lipoproteins, blood glucose, insulin, immune function, or liver enzymes when relatively high intake of IE-18:0 or palmitic acid (IE-16:0) were fed in fats with sn2-saturated fatty acids. High intake of 18:0 in natural fats can depress total lipoproteins, while IE-18:0 and IE-16:0 at high levels adversely affect lipoprotein metabolism. Still other studies have supplied interesterified fat as a single meal or fed such fat daily only in a single snack, as opposed to incorporating the fat into the entire fat pool consumed at all meals in association with most foods (which is the more physiological approach and more apt to elicit effects). Even in meal studies, IE-18:0 typically delayed fat absorption postprandially, indicating its effect on fat metabolism originating, in part, in the intestine. Mainly 2 saturated fatty acids (18:0 or 16:0) have been interesterified to harden oils, using the 16:0 from fully hydrogenated palm oil or 18:0 from fully hydrogenated soybean oil as the source material. It is not clear that IE-16:0 is as problematic as IE-18:0, but IE-16:0 has been studied less. Levels between 8% energy (%E) and 12%E from 18:0 as interesterified fat (the typical diet provides about 2%E-4%E as 18:0 from natural fats) show the most effect. Detection of adverse effects would seem to start around 7%E-8%E as IE-18:0, but one can assume that effects are initiated, even if undetected, at a lower intake, similar to the situation with TFA. Thus, although an intake of 1%E to 4%E from IE-18:0 does not appear to influence lipoproteins, it is not necessarily the only system affected. The negative effects of IE-18:0 may be alleviated or masked by dilution with other fats, especially by adding 18:2-rich polyunsaturated oils to the diet. This is similar to the trans fat story, i.e., if a limited intake of TFA is heavily diluted with other oils, the consumption of TFA fails to be detected as an adverse effect. Accordingly, more research is warranted to determine the appropriateness of interesterified fat consumption, particularly before it becomes insidiously embedded in the food supply similar to TFA and intake levels are achieved that compromise long-term health.

Effects of different protein sources on plasminogen inhibitor-1 and factor VII coagulant activity added to a fat-rich meal in type 2 diabetes

BACKGROUND

Exaggerated postprandial triglyceride concentration is believed to be atherogenic, and to influence the risk of thrombosis. Both elevated plasminogen inhibitor 1 (PAI-1) and increased factor VII coagulant activity (FVIIc) are potential important contributors to the increased risk of cardiovascular disease in type 2 diabetes.

AIM

We aimed to investigate the effect of adding four different protein types (i.e. casein, whey, cod, and gluten) to a fat-rich meal on postprandial responses of PAI-1 and FVIIc in type 2 diabetic patients.

METHODS

Twelve type 2 diabetic patients ingested four isocaloric test meals in random order. The test meals contained 100 g of butter and 45 g of carbohydrate in combination with 45 g of casein (Cas-meal), whey (Whe-meal), cod (Cod-meal), or gluten (Glu-meal), respectively. Plasma concentrations of PAI-1 and FVIIc were measured before meal, and at regular intervals for 8-h postprandially.

RESULTS

The postprandial PAI-1 concentration decreased significantly by 49% to 56% in response to the four test meals. There were no significant differences between the outcomes from the four test-meals. The FVIIc levels decreased by 8% to 11% after the meals. Again, we observed no significant differences in outcomes between the four protein-enriched meals.

CONCLUSIONS

The four proteins casein, whey, cod, and gluten, added to a fat-rich meal, all decreased the PAI-1 and FVIIc concentrations postprandially in type 2 diabetic subjects. However, postprandial levels of PAI-1 and FVIIc were not acutely influenced by the protein source.

Postprandial lipaemia does not affect resting haemodynamic responses but does influence cardiovascular reactivity to dynamic exercise

Postprandial lipaemia impairs endothelial function, possibly by changes in oxidative stress, but whether this affects cardiac output and/or systemic vascular resistance (SVR) at rest and in response to dynamic exercise remains uncertain. The present study set out to investigate the effects of a high-fat meal (HFM) v. a low-fat, high-carbohydrate meal (HCM) on cardiac output and SVR. A HFM (50 g fat) and an isoenergetic HCM (5 g fat) were randomly fed to thirty healthy adults using a crossover design. Cardiac output, heart rate and blood pressure (BP) were measured, and stroke volume and SVR were calculated over a 3 h rest following the meal, during exercise 3 h postprandially and for 45 min post-exercise. Blood samples were collected at fasting, 3 h postprandially and immediately post-exercise. Plasma TAG increased by 63.8 % 3 h following the HFM, and NEFA fell by 94.1% 3 h after the HCM. There was a 9.8% rise in plasma 8-isoprostane-F2alpha concentration following the HFM, and a 6.2% fall following the HCM. Cardiac output increased postprandially, but the difference between meals at rest or exercise was not statistically significant. The HFM resulted in a 3.2 mmHg (95% CI 0.7, 5.7) smaller increase in exercise mean arterial BP compared with the HCM due to a greater fall in exercise SVR. Postprandial lipaemia induced by a HFM does not affect cardiac output and/or SVR at rest, but it blunts the increase in BP during exercise.

Cardiovascular disease risk of dietary stearic acid compared with trans, other saturated, and unsaturated fatty acids: a systematic review

BACKGROUND

High stearic acid (STA) soybean oil is a trans-free, oxidatively stable, non-LDL-cholesterol-raising oil that can be used to replace trans fatty acids (TFAs) in solid fat applications.

OBJECTIVE

The objective was to assess the cardiovascular health effects of dietary STA compared with those of trans, other saturated, and unsaturated fatty acids.

DESIGN

We reviewed epidemiologic and clinical studies that evaluated the relation between STA and cardiovascular disease (CVD) risk factors, including plasma lipids and lipoproteins, hemostatic variables, and inflammatory markers.

RESULTS

In comparison with other saturated fatty acids, STA lowered LDL cholesterol, was neutral with respect to HDL cholesterol, and directionally lowered the ratio of total to HDL cholesterol. STA tended to raise LDL cholesterol, lower HDL cholesterol, and increase the ratio of total to HDL cholesterol in comparison with unsaturated fatty acids. In 2 of 4 studies, high-STA diets increased lipoprotein(a) in comparison with diets high in saturated fatty acids. Three studies showed increased plasma fibrinogen when dietary STA exceeded 9% of energy (the current 90th percentile of intake is 3.5%). Replacing industrial TFAs with STA might increase STA intake from 3.0% (current) to approximately 4% of energy and from 4% to 5% of energy at the 90th percentile. One-to-one substitution of STA for TFAs showed a decrease or no effect on LDL cholesterol, an increase or no effect on HDL cholesterol, and a decrease in the ratio of total to HDL cholesterol.

CONCLUSIONS

TFA intake should be reduced as much as possible because of its adverse effects on lipids and lipoproteins. The replacement of TFA with STA compared with other saturated fatty acids in foods that require solid fats beneficially affects LDL cholesterol, the primary target for CVD risk reduction; unsaturated fats are preferred for liquid fat applications. Research is needed to evaluate the effects of STA on emerging CVD risk markers such as fibrinogen and to understand the responses in different populations.

Successful manipulation of the quality and quantity of fat and carbohydrate consumed by free-living individuals using a food exchange model

Our objective in this study was to develop and implement an effective intervention strategy to manipulate the amount and composition of dietary fat and carbohydrate (CHO) in free-living individuals in the RISCK study. The study was a randomized, controlled dietary intervention study that was conducted in 720 participants identified as higher risk for or with metabolic syndrome. All followed a 4-wk run-in reference diet [high saturated fatty acids (SF)/high glycemic index (GI)]. Volunteers were randomized to continue this diet for a further 24 wk or to 1 of 4 isoenergetic prescriptions [high monounsaturated fatty acids (MUFA)/high GI; high MUFA/low GI; low fat (LF)/high GI; and LF/low GI]. We developed a food exchange model to implement each diet. Dietary records and plasma phospholipid fatty acids were used to assess the effectiveness of the intervention strategy. Reported fat intake from the LF diets was significantly reduced to 28% of energy (%E) compared with 38%E from the HM and LF diets. SF intake was successfully decreased in the HM and LF diets to < or =10%E compared with 17%E in the reference diet (P = 0.001). Dietary MUFA in the HM diets was approximately 17%E, significantly higher than in the reference (12%E) and LF diets (10%E) (P = 0.001). Changes in plasma phospholipid fatty acids provided further evidence for the successful manipulation of fat intake. The GI of the HGI and LGI arms differed by approximately 9 points (P = 0.001). The food exchange model provided an effective dietary strategy for the design and implementation across multiple sites of 5 experimental diets with specific targets for the proportion of fat and CHO.

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

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

Macronutrient intake and modulation on chylomicron production and clearance

The extent and kinetics of postprandial changes are highly variable and are modulated by numerous factors including diet, lifestyle conditions, genetic background and pathological conditions. This review focuses on dietary factors affecting postprandial chylomicron and lipoprotein metabolism in humans. The first key step in the process is fat digestion within the stomach and small intestine which can be modulated by fat and dietary fiber amounts and types. The second key step is intestinal absorption per se. The uptake and secretion of absorbed nutrients in chylomicrons is affected by numerous factors, including nutrients themselves. The amount of dietary triglycerides as well as the nature of fatty acids ingested from habitual diet or present in a test meal modulates the extent of chylomicron and plasma triglyceride levels postprandially. The amount of dietary cholesterol also modulates the extent of postprandial chylomicron and plasma triglycerides. Other nutrients can alter the postprandial occurrence of chylomicrons such as proteins, alcohol, carbohydrates or fibers. Addition of glucose and more markedly fructose, to a fat test meal increases the accumulation of chylomicrons, as does a high-glycemic index meal. In contrast, some sources of dietary fibers such as oat bran noticeably decrease the occurrence of chylomicron postprandially. Overall, changing the habitual dietary pattern, for instance from a Western-type diet to Mediterranean-type one, can in turn alter the postprandial response of the subjects. The last step in postprandial lipid metabolism is clearance from plasma through combined lipolysis processes and tissue uptake of chylomicron remnants. Both the processes can also be modulated by the nutrients. Because most day-time is usually spent in a postprandial state, the link between dietary patterns and cardiovascular health or risk is clearly mediated by the secretion and clearance rates of chylomicrons in the circulation.

Detrimental Impact of Trans Fats on Human Health: Stearic Acid-Rich Fats as Possible Substitutes

  Strong evidence demonstrated the negative effect of trans fatty acid (TFA) intake on cardiovascular diseases (CVD), diabetes, systemic inflammation, and hemostasis. As a consequence, different regulatory actions have been developed around the world, aiming to reduce human consumption of TFA. Replacement for TFA functionality requires incorporation of plastic and stable saturated fats; the present options are palm or fully hydrogenated oils. Palm oil has been described as responsible for negative biological effects on serum cholesterol levels and CVD risk. Different epidemiological and clinical studies recommend reduction of saturated fatty acid (SFA) intake, mainly myristic and palmitic acids. Experimental evidence strongly suggests that stearic acid is a wholesome substitute for TFAs and other SFAs in food manufacturing. In this article, biological effects of stearic acid on human health are reviewed in comparison to TFAs, SFAs, and unsaturated fatty acids. Current revised understanding on dietary intake, digestion, and absorption is also covered.

The effect of salatrim, a low-calorie modified triacylglycerol, on appetite and energy intake

BACKGROUND

Salatrim is modified triacylglycerol that is rich in short-chain fatty acids and stearic acid. It is used as a lower-calorie fat replacer. In addition, it has been hypothesized that salatrim's reduced absorption in the small intestine may lead to greater amounts of fat in the gastrointestinal tract, which may decrease appetite and energy intake through the release of appetite-regulating gastrointestinal hormones.

OBJECTIVE

We aimed to compare the effects of salatrim and traditional fat on appetite, ad libitum energy intake, and gastrointestinal hormones.

DESIGN

Twenty-two healthy, young, normal-weight men participated in a randomized, double-blind, crossover study. Test meals were a traditional fat meal and a salatrim meal with a mixture of traditional fat and salatrim. Visual analogue scales were used to record appetite and well-being every 30 min, and blood was sampled frequently. An ad libitum lunch was served 4.5 h after the test meal.

RESULTS

The salatrim meal increased fullness (P = 0.04) and decreased hunger (P = 0.06) significantly more than did the traditional fat meal. The traditional fat meal increased well-being (P = 0.02). There was no significant difference in ad libitum energy intake or overall energy intake between the 2 test days. No significant differences in blood glucose, insulin, triacylglycerol, ghrelin, cholecystokinin, glucagon-like peptide-1, or peptide YY concentrations were found. A significantly (P = 0.01) smaller increase in free fatty acids was observed after the salatrim meal than after the traditional fat meal.

CONCLUSIONS

Salatrim had a modestly more suppressive effect on appetite than did a traditional fat. Gastrointestinal hormones did not seem to be involved.

Chronic dietary fat intake modifies the postprandial response of hemostatic markers to a single fatty test meal

BACKGROUND

Hemostasis is the result of a complex equilibrium between coagulation and fibrinolysis, and the influence of different dietary models on this equilibrium is not entirely known.

OBJECTIVE

The objective was to compare the effects of the chronic intake of different dietary models on postprandial hemostasis.

DESIGN

In a randomized crossover design, 20 healthy men consumed for 28 d each diets rich in monounsaturated fatty acids (MUFAs), saturated fatty acids (SFAs), and carbohydrates plus n-3 fatty acids (CHO/N3). Fasting and postprandial hemostatic factors (factor VII coagulant activity, plasminogen activator inhibitor-1, tissue-type plasminogen activator, d-dimer, and thromboxane B(2)) were measured; meal tests for the postprandial measures were based on butter, virgin olive oil, and walnuts for the SFA, MUFA, and CHO/N3 diets, respectively.

RESULTS

There were no differences in the fasting variables after the dietary periods. After the 3 fatty meals were consumed, we observed an increase in thromboxane B(2) and d-dimer and a reduction in tissue plasminogen activator, irrespective of the dietary model. The MUFA or CHO/N3 meals lowered postprandial concentrations of factor VII coagulant activity, although the reduction was greater after the MUFA-enriched meal. The concentration of plasminogen activator inhibitor-1 was greater after the SFA meal than after the other 2 meals.

CONCLUSIONS

The administration of a fatty meal induces a postprandial procoagulant tendency, irrespective of the type of fat consumed. However, the use of a dietary model rich in SFA creates a more procoagulant environment than does a model that includes MUFA or CHO/N3 as the source of fatty acids.

Olive oil and the haemostatic system

Interest in the Mediterranean diet (MD) has grown worldwide due to its link with greater longevity and lower cardiovascular disease rate, cancer and age cognitive decline. Despite the high complexity of its nutrients composition, olive oil emerges as its principal food, since it provides the higher percent of energy and a lot of bioactive compounds. In this review we will discuss the benefits of diets enriched in virgin olive oil, whose effects are probably due not only to its oleic acid content but also to its other potentially health-promoting components. Traditionally, the benefits of MD were linked to its effect on lipoprotein metabolism but today we realise that there exists a whole sheaf of other benefits, including the components of haemostasis: platelet function, thrombogenesis and fibrinolysis. A diet enriched in virgin olive oil can reduce the sensitivity of platelets to aggregation, decreasing von Willebrand and tromboxane B2 plasma levels. Moreover a particular interest has arisen about its capacity to decrease fasting Factor VII plasma levels and to avoid or modulate its postprandial activation. Also Tissue Factor expression in mononuclear cells could be reduced with the chronic intake of virgin olive oil and finally, studies performed in different experimental situation have shown that it could also increase fibrinolytic activity, reducing plasma concentration of Plasma Activator Inhibitor type-1.

A low-glycemic-index diet reduces plasma plasminogen activator inhibitor-1 activity, but not tissue inhibitor of proteinases-1 or plasminogen activator inhibitor-1 protein, in overweight women

BACKGROUND

The development of obesity has been suggested to involve plasminogen activator inhibitor-1 (PAI-1) and tissue inhibitor of proteinases-1 (TIMP-1). Plasma PAI-1 is elevated in obesity. A low-glycemic-index (LGI) diet may have a beneficial effect on obesity through a decrease in plasma PAI-1, but whether it affects plasma TIMP-1 in healthy humans has not been studied.

OBJECTIVE

We investigated whether a 10-wk intake of an LGI or a high-glycemic-index (HGI), high-carbohydrate, low-fat, ad libitum diet is associated with decreases in plasma PAI-1 and TIMP-1 concentrations in overweight women.

DESIGN

Forty-four overweight women [body mass index (BMI; in kg/m2): 27.5+/-0.23] were randomly assigned to consume an HGI or an LGI diet for 10 wk. A subgroup of 29 women was assigned to participate in an additional 4-h meal test on the last day of the 10-wk intervention.

RESULTS

PAI-1 activity decreased after 10 wk of the LGI diet and was significantly different between groups. Changes in PAI-1 antigen followed the same trend, but no significant difference was observed between groups. No difference in plasma TIMP-1 concentrations was observed between groups. PAI-1 and TIMP-1 concentrations after the 4-h meal test were not significantly different between groups.

CONCLUSION

An LGI diet reduces fasting plasma PAI-1 activity and therefore may be useful for diminishing the adverse cardiovascular effects of obesity. This trial was registered at clinicaltrials.gov as NCT00324090.

Dietary, physiological, genetic and pathological influences on postprandial lipid metabolism

Most of diurnal time is spent in a postprandial state due to successive meal intakes during the day. As long as the meals contain enough fat, a transient increase in triacylglycerolaemia and a change in lipoprotein pattern occurs. The extent and kinetics of such postprandial changes are highly variable and are modulated by numerous factors. This review focuses on factors affecting postprandial lipoprotein metabolism and genes, their variability and their relationship with intermediate phenotypes and risk of CHD. Postprandial lipoprotein metabolism is modulated by background dietary pattern as well as meal composition (fat amount and type, carbohydrate, protein, fibre, alcohol) and several lifestyle conditions (physical activity, tobacco use), physiological factors (age, gender, menopausal status) and pathological conditions (obesity, insulin resistance, diabetes mellitus). The roles of many genes have been explored in order to establish the possible implications of their variability in lipid metabolism and CHD risk. The postprandial lipid response has been shown to be modified by polymorphisms within the genes for apo A-I, A-IV, A-V, E, B, C-I and C-III, lipoprotein lipase, hepatic lipase, fatty acid binding and transport proteins, microsomal triglyceride transfer protein and scavenger receptor class B type I. Overall, the variability in postprandial response is important and complex, and the interactions between nutrients or dietary or meal compositions and gene variants need further investigation. The extent of present knowledge and needs for future studies are discussed in light of ongoing developments in nutrigenetics.

Effects of stereospecific positioning of fatty acids in triacylglycerol structures in native and randomized fats: a review of their nutritional implications

Most studies on lipid lowering diets have focused on the total content of saturated, polyunsaturated and monounsaturated fatty acids. However, the distribution of these fatty acids on the triacylglycerol (TAG) molecule and the molecular TAG species generated by this stereospecificity are characteristic for various native dietary TAGs. Fat randomization or interesterification is a process involving the positional redistribution of fatty acids, which leads to the generation of new TAG molecular species. A comparison between native and randomized TAGs is the subject of this review with regards to the role of stereospecificity of fatty acids in metabolic processing and effects on fasting lipids and postprandial lipemia. The positioning of unsaturated versus saturated fatty acids in the sn-2 position of TAGs indicate differences in early metabolic processing and postprandial clearance, which may explain modulatory effects on atherogenecity and thrombogenecity. Both human and animal studies are discussed with implications for human health.

Glucagon as a determinant of fibrinolytic activity in men with different stages of glucose tolerance: impact of glucagon on fibrinolysis

Glucagon plays an important role in postprandial hyperglycemia in type 2 diabetes (T2DM), and coexists with insulin resistance and impaired fibrinolysis. We analyzed the response of plasminogen activator inhibitor-1 (PAI-1) to a lipid-glucose-protein test and the relationship between glucagon and PAI-1, tissue plasminogen activator (t-PA) and PAI-1/t-PA in 26 men with normal glucose tolerance (NGT), nine with impaired glucose tolerance (IGT) and 12 with T2DM. Fasting and postprandial PAI-1 were higher in T2DM versus NGT (P < 0.05). In univariate analysis in NGT, fasting and area under the curve (AUC) PAI-1 showed a strong relationship with fasting (P = 0.003, P = 0.006) and postprandial (P = 0.041, P = 0.045) glucagon, t-PA with fasting glucagon (P = 0.014), and PAI-1/t-PA with fasting (P = 0.047) and AUC glucagon (P = 0.017). In IGT fasting, AUC PAI-1 and PAI-1/t-PA were associated with AUC glucagon (P = 0.035, P = 0.032, P = 0.023). In NGT with the fasting metabolic parameters and insulin resistance as independent variables, fasting glucagon remained an independent covariate for PAI-1 and PAI-1/t-PA. In another model, postprandial glucagon was independently associated with PAI-1/t-PA in NGT (P < 0.05). Besides the already established determinants, we found an independent association between glucagon and fibrinolysis in NGT. Further studies are needed to identify the link between glucagon, insulin resistance and hemostasis.

The solid fat content of stearic acid-rich fats determines their postprandial effects

BACKGROUND

The process of randomization is used commercially to harden fats as an alternative to partial hydrogenation, but its effects on cardiovascular disease risk factors are uncertain.

OBJECTIVE

The objective was to compare the chronic and acute effects of randomization of a fat rich in 1,3-distearyl, 2-oleyl glycerol on fasting and postprandial lipids, glucose, insulin, and activated clotting factor VII (FVIIa) concentrations.

DESIGN

A crossover design study in 16 men compared fasting and postprandial lipid, glucose, insulin, and FVIIa concentrations at baseline and after a 3-wk diet providing 30 g unrandomized or randomized shea butter and sunflower oil blends (SSOBs), both of which contained approximately 50% stearic acid. Fecal fat excretion was measured during each dietary period. Postprandial changes were assessed after the consumption of meals providing 50 g test fat. A subsequent study compared postprandial changes after the consumption of an oleic acid-rich sunflower oil meal and an unrandomized SSOB meal.

RESULTS

Both SSOBs were well digested and absorbed. Randomization did not affect fasting or postprandial lipid, glucose, insulin, or FVIIa concentrations. Compared with the oleic acid-rich meal, the unrandomized SSOB resulted in 53% lower postprandial lipemia, 23% higher hepatic lipase activity, and a 25% lower postprandial increase in FVIIa concentration. The solid fat contents at 37 degrees C were 22%, 41%, and 0% with the unrandomized SSOB, randomized SSOB, and oleic acid-rich meals, respectively.

CONCLUSIONS

Stearic acid-rich triacylglycerol in both unrandomized and randomized forms does not adversely affect lipid risk factors for cardiovascular disease. The high proportion of solid fat at 37 degrees C may explain the decreased postprandial lipemic response.

UK Food Standards Agencycis-monounsaturated fatty acid workshop report

The UK Food Standards Agency convened a group of expert scientists to review current research investigating the optimal dietary intake forn-9cis-monounsaturated fatty acids (MUFA). The aim was to review the mechanisms underlying the reported beneficial effects of MUFA on CHD risk, and to establish priorities for future research. The issue of optimal MUFA intake is contingent upon optimal total fat intake; however, there is no consensus of opinion on what the optimal total fat intake should be. Thus, it was recommended that a large multi-centre study should look at the effects on CHD risk of MUFA replacement of saturated fatty acids in relation to varying total fat intakes; this study should be of sufficient size to take account of genetic variation, sex, physical activity and stage of life factors, as well as being of sufficient duration to account for adaptation to diets. Recommendations for studies investigating the mechanistic effects of MUFA were also made. Methods of manipulating the food chain to increase MUFA at the expense of saturated fatty acids were also discussed.

Influence of an algal triacylglycerol containing docosahexaenoic acid (22:6n-3) and docosapentaenoic acid (22:5n-6) on cardiovascular risk factors in healthy men and women

The intake of long-chainn-3 PUFA, including DHA (22:6n-3), is associated with a reduced risk of CVD.Schizochytrium sp.are an important primary source of DHA in the marine food chain but they also provide substantial quantities of then-6 PUFA docosapentaenoic acidn-6; DPA). The effect of this oil on cardiovascular risk factors was evaluated using a double-blind randomised placebo-controlled parallel-design trial in thirty-nine men and forty women. Subjects received 4g oil/d for 4 weeks; the active treatment provided 1·5g DHA and 0·6g DPA. Active treatment increased plasma concentrations of arachidonic acid, adrenic acid, DPA and DHA by 21, 11, 11 and 88mg/l respectively and the proportions of DPA and DHA in erythrocyte phospholipids by 78 and 27% respectively. Serum total, LDL- and HDL-cholesterol increased by 0·33mmol/l (7·3%), 0·26mmol/l (10·4%) and 0·14mmol/l (9·0%) compared with placebo (allp≤0·001). Factor VII (FVII) coagulant activity increased by 12% following active treatment (P=0·006). There were no significant differences between treatments in LDL size, blood pressure, plasma glucose, serum C-reactive protein, plasma FVII antigen, FVII activated, fibrinogen, von Willebrand factor, tocopherol or carotenoid concentrations, plasminogen activator inhibitor-1, creatine kinase or troponin-I activities, haematology or liver function tests or self-reported adverse effects. Overall, the oil was well tolerated and did not adversely affect cardiovascular risk.

Influence of triacylglycerol structure of stearic acid-rich fats on postprandial lipaemia

Exaggerated postprandial lipaemia may increase the risk of CHD by contributing to both thrombotic and atherogenic processes. Previous research has focused on the quantity and composition of dietary fat, whereas the effect of triacylglycerol (TAG) structure on postprandial lipaemia and clotting factor VII activity has received little attention. TAG with similar fatty acid composition may have different biochemical and physical properties that are dependent on their TAG structure, and these differences may affect lipid metabolism. Recent findings suggest that differences in the physical properties of stearic acid-rich fats are associated with differences in postprandial lipaemia, and may play an important role in determining their rates of digestion and absorption.

Effect of interesterification of palmitic acid-rich triacylglycerol on postprandial lipid and factor VII response

The process of interesterification results in changes in triacylglycerol (TAG) structure and is used to increase the melting point of dietary fats. The acute health effects of this process on palmitic acid-rich fats are uncertain with regard to postprandial lipemia, insulin and factor VII activated (FVIIa) concentrations. Two randomized crossover trials in healthy male subjects compared the effects of meals containing 50 g fat [interesterified palm oil (IPO) versus native palm oil (NPO); n=20, and IPO versus high-oleic sunflower oil (HOS); n=18], on postprandial changes in lipids, glucose, insulin, chylomicron composition and FVIIa. Compared with NPO, IPO decreased postprandial TAG and insulin concentrations. Both NPO and IPO increased FVIIa concentrations postprandially; mean increases at 6 h were 21 and 19%, respectively. Compared with HOS, IPO decreased postprandial TAG (47% lower incremental area under the curve) and reduced the postprandial increase in FVIIa concentration by 64% at 6 h; no significant differences in hepatic and total lipase activities or insulin concentrations were noted. All three test meals increased postprandial leukocyte counts (average 26% at 6 h). The fatty acid composition of the chylomicron TAG was similar to the test fats following all test meals. It is concluded that interesterification of palm oil does not result in adverse changes in postprandial lipids, insulin or FVIIa compared to high oleate and native palm oils.

Postprandial thrombin activatable fibrinolysis inhibitor and markers of endothelial dysfunction in type 2 diabetic patients

The aim of this study was to assess postprandial changes in thrombin activatable fibrinolysis inhibitor (TAFI) antigen, a thrombin-dependent fibrinolysis inhibitor with anti-inflammatory properties, and soluble markers of endothelial dysfunction in normotriglyceridemic type 2 diabetic patients. Fasting and postprandial TAFI antigen, thrombomodulin, tissue factor pathway inhibitor (TFPI), and plasminogen activator inhibitor 1 were assessed in 12 normotriglyceridemic type 2 diabetic patients treated with diet (hemoglobin A1c, 6.80% +/- 0.67%) and 14 controls. Fasting low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, free fatty acids and apolipoprotein B, and fasting and postprandial triglyceride, glucose, and insulin were also measured. Fasting TAFI was higher in the control group (102% +/- 16.9% vs 72.9% +/- 15.9%; P < .0005) and was inversely correlated with glycemic control. It decreased 4 hours after the meal (31.8% reduction [P < .005] for controls and 12.6% [P < .05] for diabetic patients) and returned to fasting levels after 8 hours. This decrement was correlated with fasting TAFI, glucose and hemoglobin A1c, and the area under the curve of glucose. Thrombomodulin, TFPI, and plasminogen activator inhibitor 1 were similar in both groups, with thrombomodulin and TFPI showing a transient postprandial increase. A fat-rich meal produces a transient increase in markers of endothelial dysfunction and a temporary reduction in TAFI, an anti-inflammatory molecule whose concentration is low in type 2 diabetes mellitus.

Ratio of oleic to palmitic acid is a dietary determinant of thrombogenic and fibrinolytic factors during the postprandial state in men

BACKGROUND

The nature of dietary fats affects the postprandial activation of the hemostatic system.

OBJECTIVE

We investigated whether the ratio of oleic to palmitic acid [and that of monounsaturated to saturated fatty acids (MUFA:SFA)] in the diet affects postprandial concentrations of triacylglycerols, tissue factor (TF), fibrinogen, tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor 1 (PAI-1).

DESIGN

We studied the effects of diets enriched in olive oil (ROO), high-palmitic sunflower oil (HPSO), butter, or a mixture of vegetable and fish oils (VEFO) on circulating concentrations of the aforementioned factors in 14 healthy men. The fats had ratios of oleic to palmitic acid (MUFA:SFA) of 6.83 (5.43), 2.36 (2.42), 0.82 (0.48), and 13.81 (7.08).

RESULTS

The largest and longest-lasting postprandial changes in plasma triacylglycerol concentrations were found with the butter-based diet (all P < 0.05). No correlation was observed between the net incremental area under the curve (netAUC) for triacylglycerol and the ratio of oleic to palmitic acid (or MUFA:SFA) in the dietary fats. The netAUCs for TF and PAI-1, however, were inversely related to the ratio of oleic to palmitic acid (and MUFA:SFA) in ROO, HPSO, butter, and VEFO. Similar results were found for the fibrinogen netAUC when VEFO was omitted from the analysis. The netAUC for t-PA was inversely correlated with postprandial concentrations of triacylglycerol.

CONCLUSIONS

Postprandial concentrations of TF, fibrinogen, and PAI-1 are associated with the ratio of oleic to palmitic acid (MUFA:SFA) in dietary fats. The postprandial t-PA response is related to postprandial concentrations of triacylglycerol.

Effect of varying the ratio of n-6 to n-3 fatty acids by increasing the dietary intake of alpha-linolenic acid, eicosapentaenoic and docosahexaenoic acid, or both on fibrinogen and clotting factors VII and XII in persons aged 45-70 y: the OPTILIP study

BACKGROUND

Elevated fibrinogen, activated factor XII (FXIIa), and factor VII coagulant activity (FVIIc) are associated with higher risk of fatal ischemic heart disease. This study tested the hypothesis that lowering the dietary ratio of n-6 to n-3 polyunsaturated fatty acids (n-6:n-3) would modify these risk factors in older men and women.

OBJECTIVE

The objective of the study was to measure fasting hemostatic risk factors and postprandial changes in activated FVII (FVIIa) concentrations after a 6-mo alteration in dietary n-6:n-3.

DESIGN

In a randomized, parallel design in 258 subjects aged 45-70 y, we compared 4 diets providing 6% of energy as polyunsaturated fatty acids at an n-6:n-3 between 5:1 and 3:1 with a control diet that had an n-6:n-3 of 10:1. The diets were enriched in alpha-linolenic acid, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, or both.

RESULTS

Fasting and 3-h plasma triacylglycerol concentrations were 11.1% and 7.2% lower with the diet that had an n-6:n-3 of approximately 3:1 and that was enriched with EPA and DHA than with the other diets. Fasting fibrinogen, FXIIa, FVIIc, FVIIa, and FVII antigen and postprandial FVIIa were not influenced by the diets. Avoiding foods high in fat the day before measurement decreased FVIIc and FVIIa by 8% and 19.2%, respectively. A test meal containing 50 g fat resulted in a mean 47% (95% CI: 42%, 52%) increase in FVIIa 6 h later, but the response did not differ by n-6:n-3.

CONCLUSION

Decreasing the n-6:n-3 to approximately 3:1 by increasing the intake of EPA and DHA lowers fasting and postprandial plasma triacylglycerol concentrations in older persons but does not influence hemostatic risk factors.

Hemostatic response to postprandial lipemia before and after exercise training

Chronic hypertriglyceridemia is thought to be atherogenic and is associated with an elevated thrombotic potential, both of which may be improved with aerobic exercise training. Eight subjects were tested for aerobic capacity, body composition, and postprandial lipemia (PPL), followed by 6 mo of exercise training and final testing. Blood samples were obtained for measurement of free fatty acid (FFA), triglycerides (TG), insulin (Ins), and glucose (Glu). Hemostatic variables including factor VII activity (FVIIa), tissue factor pathway inhibitor-factor Xa complex (TFPI/Xa), and plasminogen activator inhibitor-1 (PAI-1) antigen/activity as well as leukocyte tumor necrosis factor-alpha (TNF-alpha) gene expression were determined among four subjects. We found that the exercise training was of sufficient intensity to increase aerobic capacity (P < 0.0001) and improve body composition (P = 0.04). There were no differences between tests among PPL responses of FFA, TG, Ins, or Glu; however, the mean TG response and fat oxidation rate improved. PAI-1 antigen/activity, FVIIa, TFPI/Xa, and TNF-alpha gene expression were all improved after exercise training after adjusting for confounders. We conclude that aerobic exercise training reduces the potential for coagulation, improves fibrinolytic potential, and reduces leukocyte TNF-alpha gene expression after the ingestion of a high-fat meal.

Dietary stearic acid and risk of cardiovascular disease: Intake, sources, digestion, and absorption

Individual FA have diverse biological effects, some of which affect the risk of cardiovascular disease (CVD). In the context of food-based dietary guidance designed to reduce CVD risk, fat and FA recommendations focus on reducing saturated FA (SFA) and trans FA (TFA), and ensuring an adequate intake of unsaturated FA. Because stearic acid shares many physical properties with the other long-chain SFA but has different physiological effects, it is being evaluated as a substitute for TFA in food manufacturing. For stearic acid to become the primary replacement for TFA, it is essential that its physical properties and biological effects be well understood.

Influence of stearic acid on postprandial lipemia and hemostatic function

It has been suggested that fats rich in stearic acid may result in exaggerated postprandial lipemia and have adverse effects on hemostatic function. The effects of test meals containing different saturated and monounsaturated FA were compared in healthy subjects in a series of studies to investigate this hypothesis. Stearic acid, when present as cocoa butter, resulted in similar postprandial lipemia and factor VII activation compared with a meal containing high-oleic sunflower oil. Stearic acid when presented as shea butter or as randomized stearate-rich TAG resulted in decreased postprandial lipemia and decreased postprandial activation of factor VII. Stearic acid-rich test meals did not result in impaired fibrinolytic activity compared with either a low-fat meal or a meal high in oleate. The difference in responses between the different stearic acid-rich fats appears to be due to varying solid fat contents of the fats at 37 degrees C.

Influence of stearic acid on hemostatic risk factors in humans

Stearic acid has been claimed to be prothrombotic. Elevated plasma factor VII coagulant activity (FVIIc) may raise the risk of coronary thrombosis in the event of plaque rupture. Fibrinogen, an acute-phase protein, is necessary for normal blood clotting; however, elevated levels of fibrinogen increase the risk of coronary heart disease (CHD). Here I report the results of three controlled, human dietary intervention studies, which used a randomized crossover design to investigate the hemostatic effects of stearic acid-rich test diets in healthy young men. A diet high in stearic acid (shea butter) resulted in a 13% lower fasting plasma FVIIc than a high palmitic acid diet, and was 18% lower than a diet high in myristic and lauric acids (P = 0.001) after 3 wk of intervention. The stearic acid-rich test fat increased plasma fibrinogen concentrations slightly compared with the myristic-lauric acid diet (P < 0.01). When investigating the acute effects of fatty meals, those high in stearic acid (synthesized test fat) resulted in a smaller postprandial increase in FVII than those high in trans and oleic FA, indicating a smaller increase in activated FVII after ingesting stearic acid compared with fats high in monounsaturated FA, probably caused by lower postprandial lipemia. Thus, the present investigations did not find dietary stearic acid to be more thrombogenic, in either fasting effects compared with other long-chain FA, or in acute effects compared with dietary unsaturated FA, including trans monounsaturated FA. The slightly increased effect on fasting plasma fibrinogen may be biologically insignificant, but it should be investigated further.

Postprandial lipemia in men with metabolic syndrome, hypertensives and healthy subjects

Background

The metabolic syndrome (MetS), as well as postprandial hypertriglyceridemia, is associated with coronary heart disease. This study aimed to evaluate the postprandial lipemia after oral fat tolerance test (OFTT) in subjects with MetS and compare them to hypertensive (HTN) and healthy subjects.

Results

OFTT was given to 33 men with MetS (defined by the Adult Treatment Panel III), 17 HTN and 14 healthy men. The MetS group was further divided according to fasting triglycerides (TG) into TG ≥ 150 [MetS+TG, (n = 22)] or <150 mg/dl [MetS-TG (n = 11)], and into those with or without hypertension [MetS+HTN (n = 24), MetS-HTN (n = 9), respectively]. TG concentrations were measured before and at 4, 6 and 8 h after OFTT and the postprandial response was quantified using the area under the curve (AUC) for TG.

The postprandial response was significantly higher in MetS compared to HTN and healthy men [AUC (SD) in mg/dl/h; 2534 ± 1016 vs. 1620 ± 494 and 1019 ± 280, respectively, p ≤ 0.001]. The TG levels were increased significantly in MetS+TG compared to MetS-TG subjects at 4 (p = 0.022), 6 (p < 0.001) and 8 hours (p < 0.001). The TG were increased significantly in MetS-TG compared to healthy subjects at 4 (p = 0.011), 6 (p = 0.001) and 8 hours (p = 0.015). In linear regression analysis only fasting TG levels were a significant predictor of the AUC (Coefficient B = 8.462, p < 0.001).

Conclusion

Fasting TG concentration is the main determinant of postprandial lipemia. However, an exaggeration of TG postprandialy was found in normotriglyceridemic MetS and HTN compared to healthy subjects. This suggests that intervention to lower fasting TG levels should be recommended in MetS subjects.