The postprandial inflammatory response after ingestion of heated oils in obese persons is reduced by the presence of phenol compounds

SCOPE

Heating during the process of cooking alters the chemical properties of foods and may affect subsequent postprandial inflammation. We tested the effects of four meals rich in different oils subjected to heating on the postprandial inflammatory metabolism of peripheral blood mononuclear cells (PBMCs).

METHODS AND RESULTS

Twenty obese participants received four breakfasts following a randomized crossover design, consisting of milk and muffins made with different oils (virgin olive oil (VOO), sunflower oil (SFO), and a mixture of seeds oil (SFO/canola oil) with added either dimethylpolysiloxane (SOD), or natural antioxidants from olive mill wastewater alperujo (phenols; SOP)), previously subjected to 20 heating cycles. Postprandial inflammatory status in PBMCs was assessed by the activation of nuclear NF-κB, the concentration in cytoplasm of the NF-κB inhibitor (IκB-α), the mRNA levels of NF-κB subunits and activators (p65, IKKβ, and IKKα) and other inflammatory molecules (TNF-α, IL-1β, IL-6, MIF, and JNK), and lipopolysaccharide (LPS) levels. VOO and SOP breakfasts reduced NF-κB activation, increased IκB-α, and decreased LPS plasma concentration. SFO increased IKKα, IKKβ, p65, IL-1b, IL-6, MIF, and JNK mRNA levels, and plasma LPS.

CONCLUSION

Oils rich in phenols, whether natural (VOO) or artificially added (SOP), reduce postprandial inflammation, compared with seed oil (sunflower).

International conference on the healthy effect of virgin olive oil

1. Ageing represents a great concern in developed countries because the number of people involved and the pathologies related with it, like atherosclerosis, morbus Parkinson, Alzheimer's disease, vascular dementia, cognitive decline, diabetes and cancer. 2. Epidemiological studies suggest that a Mediterranean diet (which is rich in virgin olive oil) decreases the risk of cardiovascular disease. 3. The Mediterranean diet, rich in virgin olive oil, improves the major risk factors for cardiovascular disease, such as the lipoprotein profile, blood pressure, glucose metabolism and antithrombotic profile. Endothelial function, inflammation and oxidative stress are also positively modulated. Some of these effects are attributed to minor components of virgin olive oil. Therefore, the definition of the Mediterranean diet should include virgin olive oil. 4. Different observational studies conducted in humans have shown that the intake of monounsaturated fat may be protective against age-related cognitive decline and Alzheimer's disease. 5. Microconstituents from virgin olive oil are bioavailable in humans and have shown antioxidant properties and capacity to improve endothelial function. Furthermore they are also able to modify the haemostasis, showing antithrombotic properties. 6. In countries where the populations fulfilled a typical Mediterranean diet, such as Spain, Greece and Italy, where virgin olive oil is the principal source of fat, cancer incidence rates are lower than in northern European countries. 7. The protective effect of virgin olive oil can be most important in the first decades of life, which suggests that the dietetic benefit of virgin olive oil intake should be initiated before puberty, and maintained through life. 8. The more recent studies consistently support that the Mediterranean diet, based in virgin olive oil, is compatible with a healthier ageing and increased longevity. However, despite the significant advances of the recent years, the final proof about the specific mechanisms and contributing role of the different components of virgin olive oil to its beneficial effects requires further investigations.

Dietary fat clearance is modulated by genetic variation in apolipoprotein A-IV gene locus

Previous studies have shown that the A-IV-347Ser polymorphism is associated with the variability in low density lipoprotein (LDL)-cholesterol response to dietary therapy. The present study was designed to evaluate the association of this polymorphism with the individual variability observed in postprandial lipemic response. This polymorphism was characterized in 50 healthy male subjects homozygous for the apolipoprotein (apo)E3 allele. All subjects were subjected to a vitamin A-fat load test. Blood was drawn at time 0 and every hour over a period of 11 hours. Cholesterol and triglycerides (TG) in plasma and lipoprotein fractions of CH, TG, and retinyl palmitate (RP) were determined. Data from the postprandial lipemia revealed that subjects with the A-IV-347Ser allele (n = 14) have a lower postprandial response in total TG (P < 0.025), large triglyceride rich lipoproteins (TRL) TG (P < 0.02), and small-TRL TG levels (P < 0.007), and a higher postprandial response in large-TRL apoA-IV (P < 0.006) and apoB-100 (P < 0.041) levels than subjects homozygous for the A-IV-347Thr subjects (n = 36). In conclusion, the modifications observed in postprandial lipoprotein metabolism associated with this polymorphism within the apoA-IV gene locus may be involved in the variability in LDL-CH response observed in subjects consuming high saturated fat diets.

Plasma lipid response to hypolipidemic diets in young healthy non-obese men varies with body mass index

Lipid response to dietary fat is highly variable among individuals of a population. The aim of this study was to establish whether being overweight is one of the factors that determines this response. Forty-one non-obese healthy men were divided into two groups according to body mass index as follows: controls, <25 kg/m2; overweight, >25 kg/m2 but <30 kg/m2. After consuming a saturated fat-rich diet (SAT diet: 38% fat, 20% saturated) for 4 wk, subjects were switched to a low fat diet [National Cholesterol Education Program (NCEP)-I diet: 28% fat, 10% saturated] for 4 wk and then to a monounsaturated fat-rich diet (MUFA diet: 38% fat, 22% monounsaturated) for 4 wk. Data were analyzed by Student's t test and two-way ANOVA for repeated measures. After consuming the NCEP-I diet, the overweight subjects had a smaller decrease relative to the SAT diet period in plasma total cholesterol [-0.30 vs. -0.67 mmol/L (-7 vs. -16%), P < 0.02] and low density lipoprotein-cholesterol concentrations [-0.24 vs. -0.55 mmol/L (-9 vs. -21%), P < 0.04] than controls. However, in the overweight subjects, the MUFA diet produced a greater decrease in plasma triglycerides than in the controls relative to the SAT diet period [-0.36 vs. -0.03 mmol/L (-26 vs. -4%), P < 0.006] and to the NCEP-I diet period [-0.29 vs. 0. 01 mmol/L (-22 vs. 1%), P < 0.01). Plasma cholesterol concentrations changed to a lesser extent, and triglyceride concentration to a greater extent, in overweight but non-obese young men than in those of normal weight in response to changes in dietary fat composition. Our data suggest that in the diet treatment of obese hyperlipemic subjects, it is more important for them to lose weight than to change the fat composition of their diets.

Dietary fat clearance in normal subjects is modulated by genetic variation at the apolipoprotein B gene locus

Apolipoprotein B (apo B) plays a dominant role in cholesterol homeostasis. Several polymorphic sites within or adjacent to the gene locus for apo B have been detected. The X+ allele (XbaI restriction site present) of the XbaI restriction fragment polymorphism on the apo B gene has been found in some studies to be associated with higher serum cholesterol and/or triglyceride levels and with greater dietary response. The present study was designed to evaluate whether the apo B XbaI polymorphism was associated with the interindividual variability observed during postprandial lipemia. Fifty-one healthy young male volunteers [20 X-/X- (X-), and 31 X+/X- or X+/X+ (X+)], homozygotes for the apo E3 allele, were subjected to a vitamin A-fat load test. Subjects with the X- genotype had significantly greater retinyl palmitate (RP) and apo B-48 postprandial responses on both the large and the small TRL lipoprotein fractions compared with X+ subjects. In summary, subjects with the X-/X- genotype at the apo B locus have a greater postprandial response than X+ subjects. These differences observed in postprandial lipoprotein metabolism could explain some of the reported associations of this polymorphism to coronary heart disease risk.

Effect of 347-serine mutation in apoprotein A-IV on plasma LDL cholesterol response to dietary fat

Lipid response to dietary fat and cholesterol is, to a large extent, genetically controlled. Apoprotein (apo) A-IV has been related to fat absorption and to the activation of some of the enzymes involved in lipid metabolism. One mutation has been described in the apo A-IV gene that causes substitution of Ser for Thr at position 347. To study the influence of this mutation on the plasma LDL cholesterol (LDL-C) response in diets of various fat content and fatty acid saturation, 41 healthy male subjects were studied, 25 of whom were homozygous for the Thr allele (347Thr) and the rest who were either homozygous (n = 2) or heterozygous carriers of the Ser allele (347Ser). They consumed three consecutive diets, each of 4 weeks' duration: one rich in saturated fat (SFA diet: 38% fat, 20% saturated), a National Cholesterol Education Program (NCEP) type 1 diet (28% fat, 10% saturated), and a third rich in monounsaturated fat (MUFA diet; 38% fat, 22% monounsaturated). Carriers of the 347Ser allele presented a greater decrease in total cholesterol (-0.7 vs -0.44 mmol/L, P < .034), LDL-C (-0.62 vs -0.31 mmol/L, P < .012), and apo B (-14 vs -8 mg/dL, P < .01) levels when they were switched from the SFA to the NCEP type 1 diet than homozygous carriers of the 347Thr allele. The change from the NCEP type 1 to the MUFA diet resulted in a greater increase in total cholesterol (0.18 vs -0.05 mmol/L, P < .028) and apo B (5 vs -1 mg/dL, P < .006) levels in the 347Ser than in the 347Thr individuals. In a previous study, we demonstrated that the G-->A polymorphism at position -76 of the gene promoter of apo A-I affects the LDL-C response to dietary fat. We therefore decided to study the effect of the interaction between these mutations on this response. We found that both mutations have an additive effect on total cholesterol, LDL-C, and apo B dietary-induced changes. Our results suggest that total cholesterol and LDL-C response to dietary fat is influenced by the 347Ser mutation of apo A-IV.

Monounsaturated fatty acid-enriched diet decreases plasma plasminogen activator inhibitor type 1

An increase in levels of plasma plasminogen activator inhibitor type 1 (PAI-1) is one of the main hemostatic alterations in patients with coronary heart disease. Despite growing interest in the fibrinolytic system, few studies have been undertaken to determine the effect exerted on it by the different dietary fatty acids. We investigated the effect of a monounsaturated fat (MUFA)-rich diet in comparison with a low-fat diet (National Cholesterol Education Program step 1 diet) (NCEP-1) on factors involved in blood coagulation and fibrinolysis. We also determined the effect of dietary cholesterol on these blood parameters. Twenty-one young, male, healthy volunteers followed two low-fat/high-carbohydrate diets (< 30% fat, < 10% saturated fat, 14% MUFA) for 24 days each, with 115 or 280 mg of cholesterol per 1000 kcal per day, and two oleic acid-enriched diets (38% fat, 24% MUFA) with the same dietary cholesterol as the low-fat/high-carbohydrate diets. Plasma levels of fibrinogen, thrombin-antithrombin complexes, prothrombin fragments 1+2, plasminogen, alpha 2 antiplasmin, and tissue plasminogen activator were not significantly different among the experimental diets used in this study. Consumption of the diet rich in MUFA resulted in a significant decrease in both PAI-1 plasma activity (P < .005) and antigenic PAI-1 (P < .04) compared with the carbohydrate-rich diet (NCEP-1). The addition of dietary cholesterol to each of these diets did not result in any significant additional effect. Changes in insulin levels and PAI-1 activity were positively correlated (r = .425; P < .02). In conclusion, consumption of diets rich in MUFAs decreases PAI-1 plasma activity, which is accompanied by a parallel decrease in plasma insulin levels.

Lipoprotein concentrations in normolipidemic males consuming oleic acid-rich diets from two different sources: olive oil and oleic acid-rich sunflower oil

The effects on plasma lipid concentrations of two oleic acid-rich diets, prepared with two different plant oils--olive oil and sunflower oil high in monounsaturated fatty acids (MUFAs)-- were compared with a National Cholesterol Education Program (NCEP) I diet. Twenty-one healthy, normolipidemic, young males consumed an NCEP-I diet (30% of energy as fat) during a 25-d period. Subjects were then assigned to two 4-wk study periods, according to a randomized, crossover design. Group one was placed on an olive oil-enriched diet (40% fat, 22% MUFAs), followed by a 4-wk period of a sunflower oil-enriched diet (40% fat, 22% MUFAs). In group two, the order of the diets was reversed. Both MUFA dietary periods resulted in an increase in high-density-lipoprotein (HDL) cholesterol (7% for the olive oil diet and 4% for the sunflower oil diet) and in apolipoprotein (apo) A-I (9% for both) compared with the NCEP-I diet. Low-density-lipoprotein (LDL) cholesterol and apo B concentrations (x +/- SEM) were lower (P < 0.05) during the sunflower oil diet (2.40 +/- 0.11 mmol/L, 0.85 +/- 0.04 mg/L) than during the olive oil diet (2.64 +/- 0.15 mmol/L, 0.93 +/- 0.05 mg/L). No significant differences were observed in these variables between the sunflower oil and NCEP-I (2.48 +/- 0.13 mmol/L, 0.89 +/- 0.04 mg/L) diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of mutation in human apolipoprotein A-1 gene promoter on plasma LDL cholesterol response to dietary fat

The plasma lipid response to changes in dietary fat and cholesterol can vary between individuals. At present, responders cannot be identified in advance. An adenine to guanine (A-->G) mutation in the promoter of the apolipoprotein A1 gene (apoA-1) has been suggested as affecting plasma high-density lipoprotein cholesterol. In 50 young men we examined the effect of the same mutation on the responses of both high and low density lipoprotein cholesterol to low-fat diet. The frequency for the A allele was 0.14. Subjects were fed a low-fat diet for 25 days, followed by a diet rich in monounsaturated fatty acid (MUFA, 22% out of 40% fat) for 28 days and lipoproteins were measured at the end of each diet. There were no differences in initial total cholesterol between subjects with the G/G mutation (170 mg/dL: 100 mg/dL = 2.59 mmol/L) and the G/A mutation (169 mg/dL) genotypes. After consumption of the high monounsaturated fat diet, significant increases were noted in plasma LDL cholesterol (10 mg/dL, p = 0.035) in the G/A subjects but not in the G/G subjects (1 mg/dL, p = 0.996). These differences showed that a significant diet-gene interaction (p = 0.015) existed. No differences were observed on HDL cholesterol between groups. Plasma low-density lipoprotein cholesterol responsiveness to diet may be explained by variation at the apoA-I gene locus.