Dietary fatty acids, lipoproteins, and cardiovascular disease

Individual and interaction effects of monounsaturated fatty acids on their associations with hypertension in Chinese residents

Currently, associations between dietary intakes of individual monounsaturated fatty acids (MUFAs) and hypertension were not well disclosed, and the interaction effects of MUFAs on their associations with hypertension were unknown. Obesity was correlated with both MUFAs and hypertension, while if anthropometric obesity indices performed mediating roles in associations between MUFAs and hypertension remained underdetermined. In our study, 8509 Chinese adults investigated from 2004 to 2011 were included. Dietary information collection and physical examinations were performed at baseline and each timepoint of follow-up. As we found, inverse associations of MUFA17, MUFA18 and MUFA20 with hypertension were statistically significant after adjustments, hazard ratios (HRs) were 0.87, 0.90 and 0.91, respectively. MUFA15 was positively associated with hypertension, with an HR of 1.07 (95% confidence interval: 1.01, 1.12). By performing principal component analysis (PCA) to estimate the joint effects of MUFAs on hypertension, the PCA score of MUFAs was only inversely associated with blood pressure. No joint effect was observed in g-computation analyses. Both linear and nonlinear interactions of MUFAs on their associations with hypertension were estimated using restricted cubic spline analysis. The association between MUFA15 and hypertension was interacted by MUFA17, and the association between MUFA20 and hypertension was interacted by MUFA18. The mediation effects of body mass index and waist circumference were found on associations of hypertension with MUFA15, MUFA17 and MUFA20. Our findings suggested that associations with hypertension were different among individual MUFAs, and mutual interactions existed, implying that the utility of individual MUFAs might be recommended for estimating relationships between MUFAs and diseases. Moreover, fat accumulation might potentially underlie associations between MUFAs and hypertension.

Lipoproteins and Their Effects on the Cardiovascular System

Coronary heart disease is the foremost leading cause of death across the world. It mainly involves the blood vessels, which supply the heart. Plaque formation due to lipid deposition leads to the narrowing of the vessels, obstructing blood flow. Therefore, lipoproteins such as high-density lipoproteins (HDL), low-density lipoproteins (LDL), very low-density lipoproteins (VLDL), and chylomicrons play a crucial role in cardiovascular diseases. Lipoproteins are carrier molecules made up of proteins and fats. They carry cholesterol through the bloodstream and transport it to the peripheral tissues or the liver. There are several classes of lipoproteins in the blood, namely HDL, LDL, VLDL, and chylomicrons. Depending on the lipoproteins, an excess of them can either harm or benefit the body. Low-density lipoprotein, nicknamed 'the bad cholesterol,' transports fatty molecules from the liver and deposits them in peripheral tissues or central vessels. Thus, excess LDL can cause blockage of the arteries supplying major organs. High-density lipoprotein, nicknamed 'the good cholesterol,' transports the excess fatty molecules to the liver for their metabolism and removal from the body. Hence, high levels of HDL are an indication of a healthy body. Thus, lipoproteins are important molecules, and their proper regulation is essential to maintaining a healthy body. An effective way to maintain a balanced lipoprotein level is to have a properly balanced diet with high protein and low fat. Regular exercise, both indoors and outdoors, is recommended. If cholesterol levels are not maintained by diet and exercise, medication is advised after consulting medical experts. This review aims to inform people about lipoproteins, their importance, and maintaining a healthy lipoprotein level.

Effects of camelina oil supplementation on lipid profile and glycemic control: a systematic review and dose‒response meta-analysis of randomized clinical trials

BACKGROUND

This systematic review and dose-response meta-analysis of published randomized controlled trials (RCTs) was conducted to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycemic indices.

METHODS

Relevant RCTs were selected by searching the ISI Web of Science, PubMed, and Scopus databases up to July 1, 2022. RTCs with an intervention duration of less than 2 weeks, without a placebo group, and those that used COS in combination with another supplement were excluded. Weighted mean differences and 95% confidence intervals were pooled by applying a random-effects model, while validated methods examined sensitivity analyses, heterogeneity, and publication bias.

RESULTS

Seven eligible RCTs, including 428 individuals, were selected. The pooled analysis revealed that COS significantly improved total cholesterol in studies lasting more than 8 weeks and utilizing dosages lower than 30 g/d compared to the placebo group. The results of fractional polynomial modeling indicated that there were nonlinear dose-response relations between the dose of COS and absolute mean differences in low-density cholesterol, high-density cholesterol, and total cholesterol, but not triglycerides. It appears that the greatest effect of COS oil occurs at the dosage of 20 g/day.

CONCLUSION

The present meta-analysis indicates that COS may reduce cardiovascular disease risk by improving lipid profile markers. Based on the results of this study, COS at dosages lower than 30 g/d may be a beneficial nonpharmacological strategy for lipid control. Further RCTs with longer COS durations are warranted to expand on these results.

The Effect of MUFA-Rich Food on Lipid Profile: A Meta-Analysis of Randomized and Controlled-Feeding Trials

Since the effects of mono-unsaturated fatty acids (MUFA) on lipid profile are still controversial, a meta-analysis of randomized controlled trials was conducted in the present study to assess the effect of MUFA-rich food on lipid profiles. The study was designed, conducted, and reported according to the guidelines of the 2020 preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement. A systematic and comprehensive search was performed in several databases from inception up to 30 January 2022. The results showed that the intake of edible oil-derived MUFA (EDM) could increase the blood HDL-C level (mean difference = 0.08; 95%CI: -0.01, 0.17, p = 0.03), but did not affect the level of TC, TG, or LDL-C. Moreover, the consumption of other food-derived MUFA (ODM) significantly decreased TG concentration (mean difference = -0.35; 95%CI: -0.61, -0.09, p = 0.01)), but did not affect the level of TC, LDL-C, or HDL-C. Findings from this study suggest that MUFA-rich food might be beneficial to modulate the blood lipid profile.

Partial Replacement of Animal Fat with Full-Fat Almond in Broiler Chicken Diets: Performance, Nutrient Digestibility, Blood Profile, Cecal-Fecal Microflora Composition, and Foot-Pad Dermatitis

Simple Summary

Recently, as the price of grains in feed increases worldwide, interest in new raw materials that can replace protein and fat sources is increasing. This study evaluated the effect of full-fat almonds (FFA) on broiler nutrition. In the study, the formulation of FFA as a raw material showed higher growth performance than the basic feed. This seems to be due to the high digestibility of protein and fat and the promotion of intestinal health through the reduction of harmful microorganisms in the intestine. Therefore, FFA can be used as a high-quality protein and fat substitute as a raw material for broiler feed.

Abstract

The purpose of this study was to evaluate the effect of full-fat almonds (FFA) as an alternative protein and fat source for broiler feed on broiler productivity, nutrient digestibility, blood characteristics, cecal-fecal microflora, and foot-pad dermatitis (FPD). A total of 96, one-day-old broiler chickens (Arbor Acres) with initial body weight 41.61 ± 0.36 g were placed in 16 cages. In each trial, four treatments were set up: a basal diet partially replacing animal fat with FFA 0% (Control, CON), a basal diet partially replacing animal fat with FFA 1% (T1), a basal diet partial replacing animal fat with FFA 2% (T2), a basal diet partially replacing animal fat with FFA 4% (T3). The experiment was conducted for a total of 4 weeks. Feed conversion ratio (FCR) was higher (p < 0.05) in the T3 group of broilers at weeks 0 to 1 than in the CON group of broilers. From weeks 3 to 4, and for the entire experimental period, FCR was lower (p < 0.05) in the T3 group of broilers than in the CON and T1 groups of broilers. The apparent ileal digestibility (AID) of the ether extract (EE) was higher (p < 0.05) in the T3 group than in the other treatment groups, and AID of crude protein (CP) was higher (p < 0.05) in the T3 group than in the CON group. The apparent total tract digestibility (ATTD) of EE was lower (p < 0.05) in the CON group than in the other treatment groups, and the ATTD of CP and energy was higher (p < 0.05) in the T3 group of broilers than in the CON group of broilers. The AID and ATTD of total amino acids were higher (p < 0.05) in the T3 group than in the other treatment groups. Blood cholesterol levels were lower (p < 0.05) in the T3 group of broilers than in the CON and T1 groups of broilers, and higher (p < 0.05) in the CON group of broilers than in the T2 and T3 groups of broilers. The amount of E. coli in the cecal and fecal was lower (p < 0.05) in the T3 group than in CON and T1 groups. FPD score was higher (p < 0.05) in the T3 group of broilers than in the CON group of broilers. In conclusion, replacing a partial of animal fat with at least 4% FFA in broiler diets can increase growth performance and nutrient digestibility in broiler nutrition.

Wild pistachio (Pistacia atlantica mutica) oil improve metabolic syndrome features in rats with high fructose ingestion

OBJECTIVES

Metabolic syndrome is a multiplex risk factor for diabetes and cardiovascular disease. Since some dietary fats such as mono-unsaturated fatty acids (MUFA) modify metabolic syndrome components the aim of the present study was to evaluate the preventive effects of mixture, kernel and hull oils of wild pistachio (WP) (Pistacia atlantica mutica) as good sources of MUFA on different features of this abnormality in rats under induction.

MATERIALS AND METHODS

In this study rats were randomly assigned to six groups with 12 animals per group. Metabolic syndrome was induced by fructose solution in groups 2, 3, 4, 5, and 6. Group 3 received sunflower oil and groups 4, 5, and 6 received mixture, hull and kernel oils of WP (2 ml/kg/day), respectively, for 10 weeks. Then, lipid profiles, glycemic indices, oxidative stress and inflammatory parameters were measured using standard laboratory tests.

RESULTS

Different forms of WP oil induced hypotriglyceridemia, but the hypocholesterolemia effect was seen only in the mixed and kernel oil groups. Kernel oil also significantly reduced LDL and HDL cholesterol (P<0.05). In addition, mixed and kernel oils notably decreased glycemic indices (fasting blood glucose and insulin resistance) compared with the fructose group. Serum insulin levels were significantly increased in the kernel oil group (P<0.05). All WP oils also significantly decreased inflammation (IL-6).

CONCLUSION

The results showed that the consumption of WP kernel oil may have beneficial effects on preventing hyperglycemia, hypertriglyceridemia, hypercholesterolemia, inflammation and pancreatic secretory disorders.

Comparison of blood lipid-lowering effects of olive oil and other plant oils: A systematic review and meta-analysis of 27 randomized placebo-controlled clinical trials

Objective: We aim to report a systematic review and meta-analysis of randomized controlled trials (RCTs) on effects of olive oil consumption compared with other plant oils on blood lipids. Methods: PubMed, web of science, Scopus, ProQuest, and Embase were systematically searched until September 2017, with no age, language and design restrictions. Weighed mean difference (WMD) and 95% confidence interval (CI) were expressed as effect size. Sensitivity analyses and pre specified subgroup was conducted to evaluate potential heterogeneity. Meta-regression analyses were performed to investigate association between blood lipid-lowering effects of olive oil and duration of treatment. Results: Twenty-seven trials, comprising 1089 participants met the eligibility criteria. Results of this study showed that compared to other plant oils, high-density lipoprotein level increased significantly more for OO (1.37 mg/dl: 95% CI: 0.4, 2.36). Also OO consumption reduced total cholesterol (TC) (6.27 mg/dl, 95% CI: 2.8, 10.6), Low-density lipoprotein (LDL-c) (4.2 mg/dl, 95% CI: 1.4, 7.01), and triglyceride (TG) (4.31 mg/dl, 95% CI: 0.5, 8.12) significantly less than other plant oils. There were no significant effects on Apo lipoprotein A1 and Apo lipoprotein B. Conclusion: This meta-analysis suggested that OO consumption decreased serum TC, LDL-c, and TG less but increased HDL-c more than other plant oils.

Time and Intervention Effects of Daily Almond Intake on the Changes of Lipid Profile and Body Composition Among Free-Living Healthy Adults

Favorable health benefits of almond have been shown in several previous studies. However, repeated measures, randomized, controlled trials to investigate the changes due to almond intake based on the time effects have not yet been reported. The current study was conducted to evaluate the effects of daily almond intake on changes in body composition and lipid profiles for 20 weeks with four measurements among healthy adults. Participants in the almond group showed favorable changes on blood lipid profiles, including levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein (non-HDL-C) after consuming 56 g of almond per day for 20 weeks compared with those at baseline. At week 20, subjects in the almond group showed significantly decreased TC, LDL-C, non-HDL-C, TG, body fat mass, and waist–hip ratio compared with those of the control group who consumed isocaloric control food. The mixed model also confirmed that there were significant time effects in several bioimpedance indicators (i.e., total body protein, fat-free mass, etc.) and all of the lipid profile parameters in the almond group. These results confirm the effects of lipid-lowering and modifying body composition of almond consumption. In addition, our results suggest that the measuring time points would be critical to capture the effects of dietary intervention.

Benefits of Nut Consumption on Insulin Resistance and Cardiovascular Risk Factors: Multiple Potential Mechanisms of Actions

Epidemiological and clinical studies have indicated that nut consumption could be a healthy dietary strategy to prevent and treat type 2 diabetes (T2DM) and related cardiovascular disease (CVD). The objective of this review is to examine the potential mechanisms of action of nuts addressing effects on glycemic control, weight management, energy balance, appetite, gut microbiota modification, lipid metabolism, oxidative stress, inflammation, endothelial function and blood pressure with a focus on data from both animal and human studies. The favourable effects of nuts could be explained by the unique nutrient composition and bioactive compounds in nuts. Unsaturated fatty acids (monounsaturated fatty acids and polyunsaturated fatty acids) present in nuts may play a role in glucose control and appetite suppression. Fiber and polyphenols in nuts may also have an anti-diabetic effect by altering gut microbiota. Nuts lower serum cholesterol by reduced cholesterol absorption, inhibition of HMG-CoA reductase and increased bile acid production by stimulation of 7-α hydroxylase. Arginine and magnesium improve inflammation, oxidative stress, endothelial function and blood pressure. In conclusion, nuts contain compounds that favourably influence glucose homeostasis, weight control and vascular health. Further investigations are required to identify the most important mechanisms by which nuts decrease the risk of T2DM and CVD.

Expression of adenosine 5'-monophosphate-Activated protein kinase (AMPK) in ovine testis (Ovis aries): In vivo regulation by nutritional state

In the present study, we identified AMPK and investigated its potential role in steroidogenesis in vivo in the ovine testis in response to variation in nutritional status (fed control vs. restricted). We performed immunoblotting to show that both active and non-active forms of AMPK exist in ovine testis and liver. In testis, we confirmed these results by immunohistochemistry. We found a correlation between ATP (Adenosine-Triphosphate) levels and the expression of AMPK in liver. Also, low and high caloric diets induce isoform-dependent AMPK expression, with an increase in α2, ß1ß2 and γ1 activity levels. Although the restricted group exhibited an increase in lipid balance, only the triglyceride and HC-VLDL (Cholesterol-Very low density lipoprotein) fractions showed significant differences between groups, suggesting an adaptive mechanism. Moreover, the relatively low rate of non-esterified fatty acid released into the circulation implies re-esterification to compensate for the physiological need. In the fed control group, AMPK activates the production of testosterone in Leydig cells; this is, in turn, associated with an increase in the expression of 3ß-HSD (3 beta hydroxy steroid deshydrogenase), p450scc (Cholesterol side-chain cleavage enzyme) and StAR (Steroidogenic acute regulatory protein) proteins induced by decreased MAPK ERK½ (Extracellular signal-regulated kinase -Mitogen-activated protein kinase) phosphorylation. In contrast, in the restricted group, testosterone secretion was reduced but intracellular cholesterol concentration was not. Furthermore, the combination of high levels of lipoproteins and emergence of the p38 MAP kinase pathway suggest the involvement of pro-inflammatory cytokines, as confirmed by transcriptional repression of the StAR protein. Taken together, these results suggest that AMPK expression is tissue dependent.

Dietary oils and FADS1-FADS2 genetic variants modulate [13C]α-linolenic acid metabolism and plasma fatty acid composition

BACKGROUND

Desaturation of dietary α-linolenic acid (ALA) to omega-3 (n-3) long-chain fatty acids (FAs) is mediated through FA desaturases (FADS1-FADS2) and may be influenced by dietary FA composition.

OBJECTIVE

We investigated the effects of diets enriched in flaxseed oil (FXCO) or high-oleic acid canola oil (HOCO) compared with a Western diet (WD) and FADS1-FADS2 single nucleotide polymorphisms (SNPs) on plasma FAs and [U-(13)C]ALA metabolism.

DESIGN

In a randomized crossover design, 36 hyperlipidemic subjects consumed 3 isoenergetic diets enriched in FXCO (20.6 g ALA/d), HOCO (2.4 g ALA/d), or WD (1.3 g ALA/d) for 4 wk. On day 27, blood was sampled 0, 24, and 48 h after the subjects (n = 26) consumed 45 mg [U-(13)C]ALA. The subjects were genotyped for 4 FADS SNPs.

RESULTS

FXCO increased (P < 0.001) plasma ALA, EPA, and docosapentaenoic acid (DPA), with no change in DHA compared with the HOCO or WD diets. At 24 and 48 h, [U-(13)C]ALA recovered as plasma [(13)C]EPA and [(13)C]DPA were lower (P < 0.001) after the FXCO diet than after the HOCO and WD diets. No change in [(13)C]DHA was observed between diets. Minor allele homozygotes of rs174545, rs174583, rs174561, and rs174537 had lower (P < 0.05) plasma EPA, arachidonic acid (AA), EPA/ALA, and AA/linoleic acid compositions and lower (P < 0.05) plasma [(13)C]EPA enrichment at 24 and 48 h in comparison with carriers of the major allele after all diets. SNPs were not associated with plasma composition of DHA or [(13)C]DHA enrichment.

CONCLUSION

An increase in ALA intake resulting in increased plasma EPA composition may be cardioprotective, especially in minor allele homozygotes. This trial was registered at www.clinicaltrials.gov as NCT00927199.

A Diet Rich in Monounsaturated Fatty Acids Improves the Lipid Profile of Mice Previously on a Diet Rich in Saturated Fatty Acids

This study investigated whether switching from a diet rich in saturated fatty acids (SAFAs) to a diet rich in monounsaturated fatty acids (MUFAs) or to one with equal amounts of MUFAs-SAFAs favorably affects the lipid profile of hypercholesterolemic mice. C57BL/6 mice (n = 82) were allocated into 4 groups. The first group (control, n = 10) was fed standard chow. The 3 remaining groups (n = 24 mice/group) were fed a SAFA-rich diet for 8 weeks and were then allocated for 16 weeks to either a MUFA-rich diet, an equal in MUFAs-SAFAs-rich diet, or continued the previous SAFA-rich diet. After 8 weeks, mice consuming SAFA-rich diet had increased weight, total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) levels ( P < .05 vs baseline). At week 24, MUFA-rich and MUFA-SAFA rich diets decreased TC and low-density lipoprotein cholesterol (LDL-C) levels ( P < .05) compared with week 8. In conclusion, switching to MUFA-rich diets or substituting half of the SAFAs with MUFAs can reverse diet-induced-hypercholesterolemia.

Carcass and meat quality of rabbits given diets having a high level of vegetable or animal fat

Three groups of does were fed respectively with three experimental diets: control (C), vegetable fat enriched (V) and animal fat enriched (A). Also their offspring were given their respective diets from weaning to slaughter. C was a standard commercial diet, V had 99 g vegetable fat per kg, and A had 114 g animal fat per kg. Sixty animals in the live-weight range 1·75 to 2·25 kg from each group were slaughtered at 9 weeks of age. The rabbits came from a commercial three-way cross. Animals on diets A and V had a better food conversion efficiency ratio, a lower drip loss and a dressing yield substantially better than those given diet C. Males had higher food conversion rate and smaller dressing yield. Carcass colour was not affected by the diet but rabbits given diet V showed less pale meat. Differences in the three colour parameters were found for the three diets for hot and chilled carcass fat colour. Muscular pH measured in the longissimus dorsi and biceps femoris were slightly higher for diets A and V and were also higher for males than for females. Water-holding capacity of raw meat from rabbits given diets A and V was higher than from rabbits given the control diet. Protein and moisture content of the meat of a hind leg was almost the same for the three diets but fat content was much higher in animals given diets A and V than in the control group.

The tsim tsoum approaches for prevention of cardiovascular disease

The Tsim Tsoum Concept means that humans evolved on a diet in which nature recommends to ingest fatty acids in a balanced ratio (polyunsaturated(P) : saturated(S) =w-6 : w-3 = 1 : 1)as part of dietary lipid pattern where monounsaturated fatty acids(MUFA) is the major fatty acid(P : M : S = 1 : 6 : 1) in the background of other dietary factors; antioxidants, vitamins, minerals and fiber as well as physical activity and low mental stress. Several hundred years ago, our diet included natural foods; fruits, vegetables, green vegetables, seeds, eggs and honey. Fish, and wild meat were also available to pre-agricultural humans which shaped modern human genetic nutritional requirement. Cereal grains (refined), and vegetable oils that are rich in w-6 fatty acids are relatively recent addition to the human diet that represent dramatic departure from those foods to which we are adapted. Excess of linoleic acid, trans fatty acids (TFA), saturated and total fat as well as refined starches and sugar are proinflammatory. Low dietary MUFA and n-3 fatty acids and other long chain polyunsarurated fatty acids (LCPUFA) are important in the pathogenesis of metabolic syndrome. Increased sympathetic activity with greater secretion of neurotransmitters in conjunction of underlying long chain PUFA deficiency, and excess of proinflammatory nutrients, may damage the neurons via proinflammatory cytokines, in the ventromedial hypothalamus and insulin receptors in the brain.Since, 30–50% of the fatty acids in the brain are LCPUFA, especially omega-3 fatty acids, which are incorporated in the cell membrane phospholipids, it is possible that their supplementation may be protective.Blood lipid composition does reflect one's health status: (a) circulating serum lipoproteins and their ratio provide information on their atherogenicity to blood vessels and (b) circulating plasma fatty acids, such as w-6/w-3 fatty acid ratio, give indication on proinflammatory status of blood vessels, cardiomyocytes, liver cells and neurones; (a) and (b) are phenotype-related and depend on genetic, environmental and developmental factors. As such, they appear as universal markers for holistic health and these may be important in the pathogenesis of cardiovascular diseases and cancer, which is the main consideration of Tsim Tsoum concept.

Intake and adipose tissue composition of fatty acids and risk of myocardial infarction in a male Portuguese community sample

OBJECTIVE

To evaluate the relation between intake and adipose tissue composition of fatty acids and acute myocardial infarction in Portuguese men.

DESIGN

Case-control study. Diet was assessed using a semiquantitative food frequency questionnaire. In 49 case and 49 control subjects, adipose tissue composition was assessed by gas-liquid chromatography.

SUBJECTS/SETTING

Population-based; subjects were 297 consecutively admitted cases of first acute myocardial infarction in a tertiary care hospital who were aged>or=40 years. Three hundred ten community controls were selected by random-digit dialing.

MAIN OUTCOME MEASURE

Odds ratio (OR).

STATISTICAL ANALYSIS PERFORMED

Logistic regression, adjusting for age, education, family history of acute myocardial infarction, smoking, physical activity, body mass index, and energy intake.

RESULTS

Total fat intake (OR 0.45, fourth quartile, P=0.02), lauric acid (OR 0.44, fourth quartile, P=0.02), palmitic acid (OR 0.58, fourth quartile, P=0.03), and oleic acid (OR 0.42, fourth quartile, P=0.03) were inversely associated with acute myocardial infarction. No significant effects were found for the remaining fatty acids. In the adipose tissue composition data, the adjusted risk estimates of acute myocardial infarction for the highest vs the lowest tertile were 0.16, 0.14, and 0.04 for lauric, oleic, and trans-fatty acids, respectively. A significant direct association was found for palmitic and linoleic acids (adjusted ORs for the highest tertile were 9.02 and 3.63, respectively).

CONCLUSIONS

Low intake of total fat and lauric acid from dairy products was associated with acute myocardial infarction. The association of polyunsaturated fatty acids with risk of acute myocardial infarction was nonsignificant after adjustment for energy intake and confounders. Recommendations on fatty acid intake should aim for both an upper and lower limit.

Plasma lipid profiles and risk of cardiovascular disease in occupational lead exposure in Abeokuta, Nigeria

In order to investigate the effects of lead exposure on risk of cardiovascular disease during occupational exposure to this metal, plasma cholesterol and its fractions as high-density liporotein (HDL), low-density liporotein (LDL) and triglyceride were determined in various artisans in Abeokuta, Nigeria who have been shown to be occupationally exposed to lead and these were related to blood lead levels. Increased risk of cardiovascular disease was observed in the artisans. Total cholesterol in the artisans was between 1.5 and 2.0 times higher in the artisans than that present in controls while LDL cholesterol was between 1.6 and 2.4 times higher in the artisans when compared with control subjects [p < 0.001]. HDL cholesterol and triglyceride levels were not affected [p > 0.05]. A significant positive correlation was observed between blood lead and total cholesterol on one hand [r = 0.372; p = 3.0 × 10^-5] and blood lead and LDL cholesterol on the other hand [r = 0.283; p = 0.001]. LDL/HDL cholesterol ratio was also higher in the artisans when compared with control. Blood pressure (systolic and diastolic) and other anthropometric parameters were not significantly different between the artisans and the control subjects [p > 0.05]. Results suggest that lead exposure increases cholesterol synthesis and transport to peripheral tissues whereas reverse cholesterol transport to the liver is not affected.

Efeitos dos óleos de amendoim, açafrão e oliva na composição corporal, metabolismo energético, perfil lipídico e ingestão alimentar de indivíduos eutróficos normolipidêmicos

OBJETIVOS: O presente trabalho visou avaliar os efeitos do consumo dos óleos de amendoim, açafrão e oliva no perfil lipídico, composição corporal, metabolismo energético e ingestão alimentar em indivíduos eutróficos normolipidêmicos. MÉTODOS: Foram selecionados 32 indivíduos, divididos aleatoriamente em quatro grupos, tendo quatro mulheres e quatro homens em cada grupo, com idade entre 18 e 50 anos. Foi oferecido um milk shake aos voluntários no desjejum, veiculando uma quantidade equivalente a 30% da sua energia basal na forma de óleo (amendoim, açafrão ou oliva), por um período de oito semanas, exceto para o grupo-controle, que não recebeu o shake. Foram realizadas avaliações dos valores de colesterol total e frações, triacilgliceróis, composição corporal, taxa de metabolismo basal, termogênese induzida pela dieta e ingestão alimentar dos indivíduos nas semanas basal, 4ª e 8ª. RESULTADOS: Não foi observada diferença significante no perfil lipídico e na saciedade, no entanto, o grupo que recebeu óleo de açafrão apresentou valores de lipídios plasmáticos mais reduzidos. A ingestão dos óleos levou ao aumento do ganho de peso, sendo que o óleo de oliva proporcionou maior circunferência do quadril. CONCLUSÃO: A adição dos óleos na dieta levou ao aumento da deposição de gordura corporal sem provocar alterações no perfil lipídico e ingestão dietética, ao contrário do relatado na literatura. O uso dos óleos em substituição a outros nutrientes energéticos da dieta, o maior número de voluntários e um período maior de intervenção devem ser investigados em estudos futuros.

A Diet Rich in High-Oleic-Acid Sunflower Oil Favorably Alters Low-Density Lipoprotein Cholesterol, Triglycerides, and Factor VII Coagulant Activity

OBJECTIVE

To compare concentrations of factor VII coagulant activity (factor VIIc), fibrinogen, plasminogen activator inhibitor-1, and blood lipids on a saturated fat-rich diet with one rich in monounsaturated fat.

DESIGN

Subjects were randomly allocated to two groups. The study design was an ABB/BAA extra-period crossover. One group consumed a diet rich in saturated fatty acid (SFA) with fat making up 20.8% of total energy, for 5 weeks and then one rich in monounsaturated fatty acid (MUFA), with fat making up 20.3% of total energy for 10 weeks. The other group consumed the MUFA diet for 5 weeks followed by the SFA diet for 10 weeks.

SUBJECTS/SETTING

Men and women aged 35 to 69 years who were nonsmokers with no chronic illness and not on any medication were recruited to participate. Eighteen subjects were recruited and 15 (5 men, 10 women) completed the community-based study.

INTERVENTION

Blood was sampled at the beginning and end point of each 5-week diet period for analysis of coagulation and fibrinolysis factors and blood lipids. Subjects kept 3-day food diaries twice during each of the three diet periods and were weighed on each visit for blood collection. Analysis of plasma fatty acids was used to indicate dietary compliance.

MAIN OUTCOME MEASURES

Differences in fasting factor VIIc, fibrinogen, plasminogen activator inhibitor-1, insulin, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoproteins A-1 and B, and plasma oleic acid levels while receiving the SFA diet vs MUFA diet.

STATISTICAL ANALYSIS

A general linear model allowing for the ABB/BAA extra-period crossover, was used for each of the outcome measures.

RESULTS

Factor VIIc was lower on the MUFA diet ( P <.05) but fibrinogen and insulin concentrations and plasminogen activator inhibitor-1 activity did not differ between diets. Low-density lipoprotein cholesterol ( P <.001) and triglyceride ( P <.01) levels were lower on the MUFA diet compared with the SFA diet. A significant increase in both plasma phospholipid and neutral lipid oleic acid (P <.0001) occurred on the MUFA diet.

CONCLUSIONS

Substitution of foods rich in saturated fat with foods rich in high-oleic-acid sunflower oil and margarine has favorable outcomes on blood lipids and factor VIIc. This oil presents another useful source of MUFA for diets aimed at prevention of heart disease.

High-density lipoprotein and homocysteine levels correlate inversely in preeclamptic women in northern Nigeria

BACKGROUND

Preeclampsia/eclampsia is one of the most common complications of pregnancy. It is a cause of high morbidity for both mother and fetus, especially in developing countries. In a recent survey conducted in Gombe, Nigeria, eclampsia was found to be a major cause of maternal mortality (24.2%), second only to obstetric hemorrhage (27.1%). Previous studies have produced contradictory findings regarding total homocysteine (tHcy) levels in women with preeclampsia/eclampsia and there is little information about the relationship between particular serum lipids and tHcy. The objective of this study in Gombe was to compare the levels of serum lipids and homocysteine in healthy pregnant women and women with preeclampsia/eclampsia in Nigeria.

METHODS

The experimental subjects included 43 women with preeclampsia/eclampsia and 130 healthy pregnant women served as controls. The criteria for preeclampsia/eclampsia included the following: hypertension (blood pressure > 140/90 mmHg), total protein (> 190 mg/g creatinine), and edema. Blood sera obtained from patients and controls attending the prenatal clinics at the Specialist Hospital and the Federal Medical Center in Gombe were analyzed for tHcy, total cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, antioxidant capacity, folate, and vitamin B-12.

RESULTS

The mean tHcy concentration for the preeclamptic/eclamptic women was greater than that of the controls (10.1 vs. 8.4 micromol/l, respectively, p = 0.01). The mean concentrations of LDL-cholesterol and triacylglycerols were not different between the two groups. However, the mean HDL-cholesterol level was higher in the healthy pregnant women compared with the preeclamptic/eclamptic women (1.64 vs. 1.42 mmol/l, respectively, p = 0.02). The HDL-cholesterol concentration was correlated inversely with the tHcy concentration (p = 0.001, r = 0.51). Total homocysteine was not linked with either serum folate or vitamin B-12.

CONCLUSIONS

These results show that preeclampsia/eclampsia is associated with increased tHcy levels and that HDL levels are depressed in Nigerian women with this hypertensive, pregnancy associated disorder.

Bakery Products Enriched with Phytosterol Esters, α-Tocopherol and β-Carotene Decrease Plasma LDL-Cholesterol and Maintain Plasma β-Carotene Concentrations in Normocholesterolemic Men and Women

The hypocholesterolemic effects of phytosterols have not been evaluated in bakery products, and the addition of liposoluble antioxidants to the carrier has never been tested. We investigated the effects of consuming croissants and magdalenas (Spanish muffins) enriched with sterol esters, alpha-tocopherol and beta-carotene on plasma lipid and fat-soluble antioxidant concentrations in normocholesterolemic, habitual consumers of bakery products following their usual diet and lifestyle. Using a randomized, double-blind, placebo-controlled design, the control (C) group (n = 29) received two pieces daily (standard croissant and muffin) and the sterol ester (SE) group (n = 28), the same products with sterol esters added (3.2 g/d) for 8 wk. Total and LDL cholesterol (LDL-C) decreased in the SE group by 0.24 mmol/L (P < 0.01) and 0.26 mmol/L (P < 0.005), respectively, whereas these variables did not change in the control group. The total difference in total and LDL-C changes between groups was 0.38 mmol/L (8.9%) and 0.36 mmol/L (14.7%), respectively (P < 0.001). Within-group changes in HDL cholesterol, triacylglycerol or lipoprotein(a) concentrations did not differ. Similarly, within-group changes over time in plasma tocopherol and carotenoid concentrations did not differ between groups. Our findings suggest that bakery products are excellent carriers for phytosterols, and their consumption is associated with a decrease in total and LDL-C concentrations, with no changes in alpha-tocopherol and beta-carotene. The ability of bakery products to include sufficient quantities of beta-carotene to compensate for a potential deficiency, and the fact that their efficacy was not associated with the time of day at which they were consumed, are interesting findings.

Dietary fat saturation produces lipid modifications in peritoneal macrophages of mouse

We investigated the effects of a saturated fat diet on mice lipid metabolism in resident peritoneal macrophages. Male C57BL/6 mice were weaned at 21 days of age and assigned to either the experimental diet, containing coconut oil (COCO diet), or the control diet, containing soybean oil as fat source. Fat content of each diet was 15% (w/w). Mice were fed for 6 weeks until sacrifice. In plasma of mice fed the COCO diet, the concentration of triglyceride, total cholesterol, HLD- and (LDL+VLDL)-cholesterol, and thiobarbituric acid-reactive substances (TBARS) increased, without changes in phospholipid concentration, compared with the controls. In macrophages of COCO-fed mice, the concentration of total (TC), free and esterified cholesterol, triglyceride, phospholipid (P) and TBARS increased, while the TC/P ratio did not change. The phospholipid compositions showed an increase of phosphatidylcholine and phosphatidylserine + phosphadytilinositol, a decrease of phosphatidylethanolamine, and no change in phosphatidylglycerol. (3)H(2)O incorporation into triglyceride and phospholipid fractions of macrophages increased, while its incorporation into free cholesterol decreased. Incorporation of [(3)H]cholesterol into macrophages of COCO-fed mice and the fraction of [(3)H]cholesterol ester increased. COCO diet produced an increase in myrystic, palmitic and palmitoleic acids proportion, a decrease in linoleic and arachidonic acids and no changes in stearic and oleic acids, compared with the control. Also, a higher relative percentage of saturated fatty acid and a decrease in unsaturation index (p <0.001) were observed in macrophages of COCO-fed mice. These results indicate that the COCO-diet, high in saturated fatty acids, alters the lipid metabolism and fatty acid composition of macrophages and produces a significant degree of oxidative stress.

1-[4-[4[(4R,5R)-3,3-Dibutyl-7-(dimethylamino)-2,3,4,5-tetrahydro-4-hydroxy-1,1-dioxido-1-benzothiepin-5-yl]phenoxy]butyl]-4-aza-1-azoniabicyclo[2.2.2]octane methanesulfonate (SC-435), an ileal apical sodium-codependent bile acid transporter inhibitor alters hepatic cholesterol metabolism and lowers plasma low-density lipoprotein-cholesterol concentrations in guinea pigs

Male Hartley guinea pigs (10/group) were assigned either to a control diet (no drug treatment) or to diets containing 0.4, 2.2, or 7.3 mg/day of an ileal apical sodium-codependent bile acid transporter (ASBT) inhibitor, 1-[4-[4[(4R,5R)-3,3-dibutyl-7-(dimethylamino)-2,3,4,5-tetrahydro-4-hydroxy-1,1-dioxido-1-benzothiepin-5-yl]phenoxy]butyl]-4-aza-1-azoniabicyclo[2.2.2] octane methanesulfonate (SC-435). Based on food consumption, guinea pigs received 0, 0.8, 3.7, or 13.4 mg/kg/day of the ASBT inhibitor. The amount of cholesterol in the four diets was maintained at 0.17%, equivalent to 1200 mg/day in the human situation. Guinea pigs treated with 13.4 mg/kg/day SC-435 had 41% lower total cholesterol and 44% lower low-density lipoprotein (LDL)-cholesterol concentrations compared with control (P < 0.01), whereas no significant differences were observed with either of the lower doses of SC-435. Hepatic cholesterol esters were significantly reduced by 43, 56, and 70% in guinea pigs fed 0.8, 3.7, and 13.4 mg/kg/day of the ASBT inhibitor, respectively (P < 0.01). In addition, the highest dose of the inhibitor resulted in a 42% increase in the number of very low-density lipoprotein (VLDL) triacylglycerol molecules and a larger VLDL diameter compared with controls (P < 0.05). Acyl-CoA cholesterol/acyltransferase activity was 30% lower with the highest dose treatment, whereas cholesterol 7alpha-hydroxylase, the regulatory enzyme of bile acid synthesis, was 30% higher with the highest ASBT inhibitor dose (P < 0.05). Furthermore, bile acid excretion increased 2-fold with the highest dose of SC-435 compared with the control group (P < 0.05). These results suggest that the reduction in total and LDL-cholesterol concentrations by the ASBT inhibitor is a result of alterations in hepatic cholesterol metabolism due to modifications in the enterohepatic circulation of bile acids.

Effect of a rapeseed oil substituting diet on serum lipids and lipoproteins in children and adolescents with familial hypercholesterolemia

OBJECTIVE

Familial hypercholesterolemia (FH) is a predominantly inherited disorder, which contributes to a defect of the LDL-cholesterol receptor. For adults with familial hypercholesterolemia (FH), it is known that a supplementary diet of monounsaturated fatty acids reduces elevated levels of total cholesterol and LDL-cholesterol and may further increase HDL-cholesterol. In particular the reduced intake of dietary fat reduces total serum cholesterol and LDL-cholesterol in the range of 10% to 15% and inhibits LDL-oxidation. Once the diagnosis of familial hypercholesterolemia is made in early childhood a supplementary diet with rapeseed oil should be started as early as possible to prevent development of atherosclerosis and subsequent complications. So far there are no reports of a lipid lowering diet enriched with rapeseed oil in children and adolescents.

METHODS

Seventeen children and young adolescents (male = 6, female = 11, ages 4 to 19 years) diagnosed with FH were enrolled in this study. They received dietary training and a classical low fat/low cholesterol diet enriched with rapeseed oil over five months. In the first two months they received orally mean 15 g/day (8-23 g/day), for the remaining three months mean 22 g/day (15-30 g/day) rapeseed oil. The calculation of the three-days dietary protocols showed the following characteristics: 29.5% calories from fat, 14.3% calories from protein and 54.6% calories from carbohydrates. The subjects had six sessions of dietary counseling, and serum lipids levels and lipoprotein(a) were estimated; each month's diet adherence was controlled by a dietitian and discussed with the patients and their families during this five-month study.

RESULTS

During five months of rapeseed oil diet serum triglycerides decreased by 29% (119.2+/-62.8 mg/dL vs. 84.9 mean +/- 39.7 mg/dL), VLDL-cholesterol by 27% (23+/-12 mg/dL vs. 17+/-8 mg/dL), total cholesterol by 10% (233+/-35 mg/dL vs. 213+/-36 mg/dL), LDL-cholesterol by 7% (151+/-31 mg/dL vs. 142+/-31 mg/dL). HDL-cholesterol (59+/-15 mg/dL vs. 57+/-11 mg/dL) and Lp(a) (29.8+/-36.3 mg/dL vs. 32.6+/-40.7 mg/dL) were not changed significantly. The diet was well accepted; in most families a sustained change was reported.

CONCLUSIONS

Our results indicate that in children and adolescents with FH a lipid-lowering diet with rapeseed oil has a similar effect on total serum cholesterol and LDL-cholesterol compared to classical cholesterol reduction diets (step I). However, an additional pronounced effect on lowering of triglycerides and VLDL-cholesterol can be observed.

Effect of two high-oleic oils on the liver lipid composition of spontaneously hypertensive rats

Despite having similar fatty acid composition and plasma lipid composition after ingestion, olive oil, but not high-oleic sunflower oil (HOSO), is capable of reducing blood pressure. HOSO contains mainly triolein, whereas olive oil contains important amounts of dioleoyl-palmitoyl-glycerol. In order to see if its different triacylglycerol (TAG) composition could be related to the hypotensive effect of olive oil, Spontaneously Hypertensive Rats (SHR) were fed with HOSO and olive oil-rich diets. Liver lipid composition was determined. Total lipid, fatty acid and TAG composition was analyzed. Rats fed olive oil (67.24 +/- 4.23) were observed to retain more dioleoyl-acyl-glycerol species in their liver than those fed HOSO (56.6 +/- 3.95), specially triolein (20.69 +/- 1.77 olive oil, vs. 12.54 +/- 1.97 HOSO), in spite of its lower content of this TAG. On the contrary, rats consuming HOSO had higher amounts of dilinoleoyl-acyl-glycerol species (9.26 +/- 1.57 HOSO, vs.4.02 +/- 0.90 olive oil). In conclusion, olive oil provided a more beneficial TAG profile in the liver of SHR rats than HOSO, probably due to the differences in the TAG composition of both oils.

Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women

BACKGROUND

Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight.

OBJECTIVE

The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity.

DESIGN

A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30-38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints.

RESULTS

Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption.

CONCLUSION

Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.

High-monounsaturated fatty acid diets lower both plasma cholesterol and triacylglycerol concentrations

BACKGROUND

Low-fat diets increase plasma triacylglycerol and decrease HDL-cholesterol concentrations, thereby potentially adversely affecting cardiovascular disease (CVD) risk. High-monounsaturated fatty acid (MUFA), cholesterol-lowering diets do not raise triacylglycerol or lower HDL cholesterol, but little is known about how peanut products, a rich source of MUFAs, affect CVD risk.

OBJECTIVE

The present study compared the CVD risk profile of an Average American diet (AAD) with those of 4 cholesterol-lowering diets: an American Heart Association/National Cholesterol Education Program Step II diet and 3 high-MUFA diets [olive oil (OO), peanut oil (PO), and peanuts and peanut butter (PPB)].

DESIGN

A randomized, double-blind, 5-period crossover study design (n = 22) was used to examine the effects of the diets on serum lipids and lipoproteins: AAD [34% fat; 16% saturated fatty acids (SFAs), 11% MUFAs], Step II (25% fat; 7% SFAs, 12% MUFAs), OO (34% fat; 7% SFAs, 21% MUFAs), PO (34% fat; 7% SFAs, 17% MUFAs), and PPB (36% fat; 8% SFAs, 18% MUFAs).

RESULTS

The high-MUFA diets lowered total cholesterol by 10% and LDL cholesterol by 14%. This response was comparable with that observed for the Step II diet. Triacylglycerol concentrations were 13% lower in subjects consuming the high-MUFA diets and were 11% higher with the Step II diet than with the AAD. The high-MUFA diets did not lower HDL cholesterol whereas the Step II diet lowered it by 4% compared with the AAD. The OO, PO, and PPB diets decreased CVD risk by an estimated 25%, 16%, and 21%, respectively, whereas the Step II diet lowered CVD risk by 12%.

CONCLUSION

A high-MUFA, cholesterol-lowering diet may be preferable to a low-fat diet because of more favorable effects on the CVD risk profile.

Regulation of guinea pig hepatic acyl-coa:cholesterol acyltransferase activity by dietary fat saturation and cholesterol

We measured the interactive effects of dietary cholesterol and fat on the regulation of hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activity and its relationship to hepatic microsomal lipid composition in guinea pigs fed 15 g/100 g (w/w) fat diets (corn oil, olive oil, or lard) with 0.01, 0.08, 0.17, or 0.33 g/100 g (w/w) added cholesterol. Guinea pigs exhibited a dose dependent increase in hepatic microsomal ACAT activity, with increasing levels of cholesterol intake (P < 0.001) in all dietary fat groups. Animals fed monounsaturated olive oil had the highest hepatic ACAT activity with the exception of the 0.33 g/100 g cholesterol diet (P < 0.001). There were no differences in ACAT activity with intake of polyunsaturated corn oil or saturated lard. Dietary cholesterol resulted in increased microsomal free cholesterol (FC) concentrations in a dose dependent manner but had no effects on microsomal phosphatidylcholine (PC) concentrations. Guinea pigs fed olive oil generally had the highest microsomal FC/PC molar ratios, and hepatic ACAT activities correlated significantly with this parameter. After modification of the lipid compositions of the microsomes from guinea pigs fed the 12 test diets with FC/PC liposome treatment, microsomal ACAT activities remained significantly related to the microsomal FC/PC molar ratios, and dietary fat type did not affect this correlation. Our findings do not support the hypothesis that the stimulation of hepatic ACAT activity with cholesterol intake is enhanced by polyunsaturated fat intake. The data demonstrate that although dietary fat type and cholesterol amount have differential effects on hepatic ACAT activity, substrate availability, expressed as microsomal FC/PC molar ratio, is a major regulator of hepatic microsomal ACAT activity.

Cookies enriched with psyllium or oat bran lower plasma LDL cholesterol in normal and hypercholesterolemic men from Northern Mexico

BACKGROUND

Psyllium and oat bran have been shown to lower plasma LDL cholesterol levels in different populations. Hypercholesterolemia is prevalent in the Northern part of Mexico and might be associated to dietary habits and sedentary lifestyle.

METHODS

Sedentary normal (cholesterol<200 mg/dL) (n=36) and hypercholesterolemic (cholesterol>220 mg/dL) (n=30) men from the Northern part of Mexico aged 20 to 45 years of age participated in an 8-week study to determine the effects of dietary soluble fiber, either psyllium or oat bran, in lowering plasma LDL cholesterol in this population. Fiber was administered by feeding the subjects an amount of cookies (100 g) equivalent to 1.3 or 2.6 g/day of soluble fiber from psyllium or oat bran, respectively. Subjects were randomly allocated to three groups: a control group consuming cookies with wheat bran, a known source of fiber with no cholesterol lowering effects, psyllium, or oat bran.

RESULTS

Food frequency questionnaires indicated that subjects from the three groups had similar intakes of foods classified as hypercholesterolemic (p>0.05). Plasma LDL cholesterol concentrations were reduced by an average of 22.6 and 26% in the psyllium and oat bran groups (p<0.001) while a non-significant reduction of 8.4% was observed in the hypercholesterolemic individuals from the control group. No effects on plasma HDL or triglycerides levels were observed among the three dietary treatments except for hypercholesterolemic individuals supplemented with oat bran where a 28% reduction in plasma triglycerides was observed after 8 weeks (p<0.01).

CONCLUSION

These results indicate that psyllium and oat bran are efficacious in lowering plasma LDL cholesterol in both normal and hypercholesterolemic individuals from this population.

Dietary soluble fiber lowers plasma LDL cholesterol concentrations by altering lipoprotein metabolism in female guinea pigs

This experiment was designed to evaluate the effects of pectin (PE), guar gum (GG) and psyllium (PSY) intake on VLDL and LDL metabolism in female guinea pigs fed high dietary cholesterol. Guinea pigs were fed a 15 g/100 g fat diet containing 0.25 g/100 g cholesterol with 12.5 g/100 g PE, 12.5 g/100 g GG, 7.5 g/100 g PSY or 12.5 g/100 g cellulose (control diet) for 4 wk. Plasma cholesterol concentrations were 29, 43 and 39% lower in guinea pigs fed PE, GG or PSY, respectively, compared with the control group (P < 0.0001). Plasma apolipoprotein (apo) B concentrations were 16-22% lower in the groups fed soluble fiber compared with the control group (P < 0.01). In contrast, hepatic cholesterol and triglyceride concentrations were not different among the PE, GG, PSY and control groups. No differences in triacylglycerol (TAG) or apo B secretion rates, measured by blocking VLDL catabolism by triton (WR 1339) injection, were observed, whereas plasma LDL apo B fractional catabolic rates (FCR), determined by injection of radiolabeled LDL, were higher in guinea pigs fed GG or PSY than in those from the control group. All sources of dietary soluble fiber reduced LDL apo B flux (P < 0.05). These results suggest that the mechanisms of plasma LDL cholesterol lowering by dietary soluble fiber are distinctive for each fiber source and result in specific alterations in lipoprotein metabolism in female guinea pigs. Differences between male and female guinea pigs in response to these diets are discussed.

Composition of human VLDL triacylglycerols after ingestion of olive oil and high oleic sunflower oil

This work was undertaken to determine the effect of diets enriched with olive oil or high oleic sunflower oil on very low density lipoprotein (VLDL) triacylglycerol composition of healthy human subjects. Both oils contain a similar proportion of monounsaturated fatty acids (MUFA) but differ in their triacylglycerol composition. All 22 human subjects initially consumed a low fat, high carbohydrate diet as recommended by the National Cholesterol Education Program (NCEP-I). They then consumed the two experimental oils (40% dietary energy) in a crossover design. The olive oil and high oleic sunflower oil diets resulted in significant increases in palmitoleic (55%, P < 0.05), oleic (27%, P < 0.01) and eicosenoic (>100%, P < 0.001) acids of VLDL triacylglycerols, whereas there was a significant decrease in linoleic acid (38%, P < 0.001). In addition, the high oleic sunflower oil diet increased the content of stearic acid (60%, P < 0.05) and total saturated fatty acids (14%, P < 0.05). Both MUFA-rich diets significantly (P < 0.01) decreased the content of sn-glycerol-palmitate-linoleate-oleate, sn-glycerol-palmitoleate-dioleate and sn-glycerol-palmitate-dilinoleate in VLDL with regard to the NCEP-I diet, whereas they increased the content of sn-glycerol-trioleate (>100%, P < 0.001 after the olive oil diet; 80%, P < 0.05 after the high oleic sunflower oil diet). Intake of olive oil, in particular, significantly decreased the content of sn-glycerol-tripalmitate (36%, P < 0.01) and increased the content of dioleoyl-containing triacylglycerols. MUFA (P < 0.01) and arachidonic acid (P < 0.001) tended to be rich in the sn-2 position of VLDL triacylglycerols during the periods of consuming the olive oil or high oleic sunflower oil diets. In addition, olive oil, but not high oleic sunflower oil, further contributed to VLDL triacylglycerols that contained alpha-linolenic and docosahexaenoic acids acylated in the sn-2 position. These data suggest that differences in the composition of VLDL triacylglycerols may be of major importance in explaining the beneficial effects of dietary olive oil in reducing the atherogenic risk profile in healthy subjects.

Regulation of very low density lipoprotein apo B metabolism by dietary fat saturation and chain length in the guinea pig

Studies investigated the effects of dietary fatty acid composition and saturation on the regulation of very low density lipoprotein (VLDL) apo B flux, clearance, and conversion to low density lipoprotein (LDL) in guinea pigs fed semipurified diets containing 15% (w/w) corn oil (CO), lard (LA), or palm kernel oil (PK). Plasma cholesterol levels were highest with dietary PK (3.1 +/- 1.0 mmol/L) followed by LA (2.4 +/- 0.4 mmol/L) and CO (1.6 +/- 0.4 mmol/L) intake. VLDL particles were larger (P < 0.05) in the LA (78 +/- 7 nm) and PK (69 +/- 10 nm) groups compared to animals fed CO (49 +/- 5 nm). VLDL-apo B fractional catabolic rates (FCR) were highest in guinea pigs fed the LA diet (P < 0.05) and VLDL apo B flux, estimated from VLDL 125I-apo B turnover kinetics, were higher in LA compared to PK or CO fed guinea pigs. In the case of PK consumption, the kinetic estimates of VLDL apo B flux significantly underestimated rates compared to direct VLDL apo B secretion measurements and LDL turnover analyses. These data demonstrate that differences in the composition and amount of saturated fatty acids have differential effects on VLDL apo B flux, catabolism, and conversion to LDL which, together with changes in LDL receptor-mediated catabolism, determine plasma LDL cholesterol levels in guinea pigs. The data also indicate that kinetic analysis of VLDL metabolism in PK fed animals is inaccurate possibly due to the presence of a small, nonequilibrating pool of newly synthesized VLDL which is rapidly converted to LDL.

Association of apo E polymorphism with plasma lipid levels in a multiethnic elderly population

Apolipoprotein E polymorphisms are important determinants of blood lipid levels and have been associated with longevity and atherosclerosis. However, information is limited on the effects of apo E variation on the lipids of nonwhite and elderly individuals. We tested the hypothesis that apo E polymorphisms are associated with plasma lipid levels in an elderly, multiethnic population. Cross-sectional data from 1068 noninstitutionalized individuals from northern Manhattan over the age of 64 who were not on a lipid-lowering diet or drug were analyzed. The ethnic distribution was 34% African-Americans, 47% Hispanics, and 19% non-Hispanic Caucasians. In the entire group, the most prevalent apo E allele was epsilon 3 (76%), followed by epsilon 4 (16%) and epsilon 2 (8%); epsilon 4 was more prevalent in African-Americans (21%) than in non-Hispanic Caucasians (12%) or Hispanics (14%). The apo epsilon 2 allele was the most important correlate of plasma lipids, but association varied across ethnoracial groups. After being adjusted for age, sex, obesity, diabetes mellitus, and alcohol intake, LDL cholesterol levels declined with each apo epsilon 2 allele by 8.8 mg/dL in Hispanics and by 25.6 and 18.1 mg/dL in non-Hispanic Caucasians and African-Americans, respectively (P < .001). No significant independent effect was noted for any apo E genotype on HDL cholesterol. Overall, there was a reduction in the total/HDL cholesterol ratio, per apo epsilon 2 allele, of 0.82 in non-Hispanic Caucasians and 0.43 and 0.48 in African-American and Hispanic individuals, respectively (P < .05). In a multivariate model, apo epsilon 4 did not significantly affect plasma lipid levels. Plasma triglyceride levels were inversely correlated with the number of apo epsilon 4 alleles (175, 159, and 143 mg/dL with 0, 1, and 2 alleles, respectively; P =.002), and this effect increased with age. Thus, in an elderly, multiethnic population, apolipoprotein E polymorphisms were important determinants of blood lipids, with differing effects depending on ethnicity. The presence of apo epsilon 2 was associated with lower LDL cholesterol levels and total/HDL cholesterol ratio, although apo epsilon genotype did not influence HDL cholesterol levels. Prospective studies are needed to test whether apo epsilon 2 protects against incident cardiovascular disease in the elderly.

Effect of dietary fats rich in lauric, myristic, palmitic, oleic or linoleic acid on plasma, hepatic and biliary lipids in cholesterol-fed hamsters

Effects of different dietary fats on plasma, hepatic and biliary lipids were determined in male golden Syrian hamsters (Mesocricetus auratus) fed on purified diets for 7 weeks. Diets were made by blending different fats containing characteristic fatty acids: butter (14:0 + 16:0), palm stearin (16:0), coconut oil (12:0 + 14:0), rapeseed oil (18:1), olive oil (18:1) and sunflowerseed oil (18:2). In all diets except the sunflowerseed oil diet dietary 18:2 was held constant at 2% energy. Total fat supplied 12% of energy and cholesterol was added at 4 g/kg diet. Plasma cholesterol and triacyglycerol concentrations were increased by dietary cholesterol. After 7 weeks, plasma cholesterol concentrations were highest with the palm stearin, coconut oil and olive oil diets (8.9, 8.9 and 9.2 mmol/l) and lowest with the rapeseed oil and sunflowerseed oil diets (6.7 and 5.5 mmol/l) while the butter diet was intermediate (8.5 mmol/l). Hepatic cholesterol concentration was highest in hamsters fed on the olive oil diet and lowest with the palm stearin diet (228 v. 144 mumol/g liver). Biliary lipids, lithogenic index and bile acid profile of the gall-bladder bile did not differ significantly among the six diets. Although the gallstone incidence was generally low in this study, three out of 10 hamsters fed on the palm stearin diet developed cholesterol gallstones. In contrast, no cholesterol gallstones were found with the other diets. Rapeseed and sunflowerseed oils caused the lowest plasma cholesterol and triacyglycerol concentrations whereas olive oil failed to demonstrate a cholesterol-lowering effect compared with diets rich in saturated fatty acids. Since 18:2 was kept constant at 2% of energy in all diets, the different responses to rapeseed and olive oils could possibly be attributed to their different contents of 16:0 (5.6% v. 12.8% respectively). Other possible explanations are discussed.

Olive oil and rapeseed oil differ in their effect on plasma low-density lipoprotein metabolism in the guinea-pig

The effects of olive oil and rapeseed oil, two different high-oleic-acid oils, on plasma LDL and hepatic cholesterol metabolism were compared in guinea-pigs. Animals were fed on semipurified diet containing 150 g fat/kg as either olive oil (OL), rapeseed oil plus 100 g palm oil/kg (C-P) or olive oil plus 350 g safflowerseed oil/kg (OL-S). Olive oil was enriched with safflowerseed oil (OL-S diet) to increase linoleic acid and to decrease palmitic acid concentrations, in order to evaluate whether differences in plasma LDL concentrations were due to intrinsic effects of the specific oil (rapeseed or olive oil) or to differences in the content of specific fatty acids. No differences due to dietary fat source were found in plasma total and HDL-cholesterol levels or in LDL composition. Plasma LDL-cholesterol levels were lower on the C-P diet than the OL diet (P < 0.05) while plasma LDL-cholesterol levels in animals fed on the OL-S diet were not significantly different from either dietary group (P > 0.05). The number of hepatic apo B/E (LDL) receptors was on average 25% higher in animals fed on the C-P diet compared with those fed on diets containing olive oil. Likewise, cardiac muscle lipoprotein lipase (EC 3.1.1.34) activity was significantly higher in the C-P group than in the OL and OL-S dietary groups. Dietary fat source had no effect on hepatic cholesterol levels or 3-hydroxy-3-methylglutaryl (HMG) CoA reductase (EC 1.1.1.34) activity. The results indicate that olive oil and rapeseed oil, both rich sources of monounsaturated fatty acids, differ in their effect on LDL metabolism in the guinea-pig.