Fatty acids and cardiovascular disease

Full-fat dairy products and cardiometabolic health outcomes: Does the dairy-fat matrix matter?

Reducing dairy fat intake is a common dietary guideline to limit energy and saturated fatty acid intake for the promotion of cardiometabolic health. However, research utilizing a holistic, food-based approach to assess the consumption of the fat found in dairy, a broad and diverse food group, may provide new insight into these guidelines. Dairy fat is comprised of a diverse assembly of fatty acids, triacylglycerols, sterols, and phospholipids, all uniquely packaged in a milk fat globule. The physical structure of this milk fat globule and its membrane is modified through different processing methods, resulting in distinctive dairy-fat matrices across each dairy product. The objectives of this narrative review were to first define and compare the dairy-fat matrix in terms of its unique composition, physical structure, and fat content across common dairy products (cow's milk, yogurt, cheese, and butter). With this information, we examined observational studies and randomized controlled trials published within the last 10 years (2013-2023) to assess the individual effects of the dairy-fat matrix in milk, yogurt, cheese, and butter on cardiometabolic health and evaluate the implications for nutrition guidance. Searches conducted on Ovid MEDLINE and PubMed® utilizing search terms for cardiometabolic health, both broadly and regarding specific disease outcomes and risk factors, yielded 59 studies that were analyzed and included in this review. Importantly, this review stratifies by both dairy product and fat content. Though the results were heterogeneous, most studies reported no association between intake of these individual regular-fat dairy products and cardiometabolic outcome measures, thus, the current body of evidence suggests that regular-fat dairy product consumption may be incorporated within overall healthy eating patterns. Research suggests that there may be a beneficial effect of regular-fat milk and yogurt intake on outcome measures related to body weight and composition, and an effect of regular-fat cheese intake on outcome measures related to blood lipids, but more research is necessary to define the directionality of this relationship. Lastly, we identify methodological research gaps and propose future research directions to bolster the current evidence base available for ascertaining the role of dairy fat in a healthy diet.

Linseed Oil Attenuates Liver Inflammation, Fatty Acid Accumulation, and Lipid Distribution in Periportal and Perivenous Hepatocytes Induced by a High-Carbohydrate Diet in Mice

We evaluated whether linseed oil (LO) modulates the effects of a high-carbohydrate diet (HCD) on liver inflammation, fatty acid (FA) accumulation, and lipid distribution in periportal and perivenous hepatocytes. The control group (control high-carbohydrate diet [HCD-C]) received an HCD with lard and soybean oil as the lipid source. The L10 and L100 groups received the HCD with 10% and 100% of LO as the lipid source, respectively. The animals were killed by decapitation before (day 0) and after receiving the diets. Liver FA composition, inflammation, and fibrogenesis gene expression were evaluated. Also, the percentage of lipid-occupied area in periportal end perivenous hepatocytes were measured. The L100 group exhibited a higher (P < .05) liver amount of omega-3 polyunsaturated FA (n-3 PUFA) and lower (P < .05) amounts of saturated FA (SFA), monounsaturated FA (MUFA), and omega-6 polyunsaturated FA (n-6 PUFA) compared with L10 or HCD-C mice. On day 56, interleukin 10 and type IV collagen gene expression were significantly upregulated and downregulated, respectively in L100. Also, the L100 group showed lower (P < .05) FA accumulation (i.e., total FA, SFA, MUFA, and n-6 PUFA). Also, L10 and L100 presented lower (P < .05) percentage of high lipid-containing portion in periportal and perivenous hepatocytes. We concluded that LO attenuation of liver inflammation promoted by an HCD is associated with increased liver n-3 PUFA levels, so modulating FA composition, deposition, and distribution in periportal and perivenous hepatocytes.

Serum fatty acids profile and association with early-onset coronary artery disease

Background:

Fatty acids (FAs) play crucial roles in modulating and preventing diseases in humans, including early-onset coronary artery disease (EOCAD). In this study, we aimed to provide a profile of FAs in the serum of EOCAD patients and identify potential EOCAD-associated FAs.

Methods:

In the first stage, we analyzed the FAs profiles in pooled samples of patients with EOCAD using gas chromatography-mass spectrometry. In the second stage, the serum levels of the candidate FAs were validated in EOCAD patients.

Results:

A total of 128 EOCAD patients and 64 controls were included in the study. Forty-nine serum FAs were quantified in pooled samples; three ω-3 FAs were identified to be associated with EOCAD. Moreover, results from the validation stage indicated that serum levels of docosahexaenoic acid (DHA) were significantly lower in EOCAD patients (55.43 ± 33.86 µg/ml) and myocardial infarction (MI) patients (47.49 ± 28.44 μg/ml) than those in the controls (70.65 ± 43.56 µg/ml). Multivariate regression analysis revealed that elevated serum DHA level was an independent protective factor for EOCAD [odds ratio (OR) = 0.8917, 95% confidence interval (CI): 0.879–0.957] and MI (OR = 0.835, 95% CI: 0.799–0.862). Decreased serum levels of docosapentaenoic acid (DPA) and eicosapentaenoic acid (EPA) were observed in the early-onset MI group.

Conclusion:

The study provided the serum FAs profile of EOCAD and confirmed that the decrease in serum levels of DHA, DPA, and EPA was associated with EOCAD. These findings might contribute to understanding the cardiovascular effects of FAs, particularly the protective effects of ω-3 polyunsaturated FAs.

A Validated Method for Quantification of Fatty Acids Incorporated in Human Plasma Phospholipids by Gas Chromatography-Triple Quadrupole Mass Spectrometry

Fatty acids (FA) are important mediators of health maintenance and disease risk. Optimal quantification assays of FA in high and low abundance as well the identification of 13C-labeled tracers to monitor FA metabolism are of major interest. The article on hand reports about the development and validation of a gas chromatography (GC)-triple quadrupole mass selective detection (GC-TQMS) method for absolute quantification of FA in human plasma phospholipids (hpPL). The quantification of the calibration solution by GC-flame ionization detection (GC-FID), with the introduction of a correction factor, allows the direct comparison of individual FA concentrations in hpPL by GC-TQMS. Specificity, sensitivity, and reproducibility are achieved by optimized chromatographic separation and employment of GC-TQMS. The inter-method comparison between GC-FID and GC-TQMS concentrations revealed good comparability for 27 FA. A full validation has been performed with linearity over 4 magnitudes, a limit of detection of 0.18-38.3 fmol on column, a recovery of 83.6-109.6%, and intraday and interday precision data meeting the criteria of EMA and FDA guidelines. The method includes the absolute quantification of 58 positional and geometrical (cis/trans) isomeric FA in hpPL in the concentration range of 1-3000 nmol/mL, covering also low abundant positional cis/trans isomers. Results obtained from both methods are highly comparable, and selectivity and sensitivity are improved by using GC-TQMS. Additionally, we show here that calculation of 13C-labeled C16:0 tracer/tracee ratios in hpPL in human isotope enrichment studies is possible.

Inclusion of Sunflower Oil in the Bovine Diet Improves Milk Nutritional Profile

Milk and its derivatives are important foods that contribute to daily nutrient requirements and improve consumers' health. This study evaluated the effects of supplementing the diet of lactating dairy cows with sunflower oil (SFO), selenium, and vitamin E on the milk's fatty acid profile and fat oxidative stability as well as the acceptability of the milk by consumers. For this purpose, 32 Jersey dairy cows were allocated to four treatment groups for 60 days, as follows: C (control diet); A (3.5 mg/kg DM (dry matter) organic selenium + 2000 IU vitamin E/cow per day); O (4% SFO DM); OA (equal doses of A and O treatments). The inclusion of SFO decreased the contents of 10:0, 10:1, 11:0, 12:0, 12:1, 14:0, and 9c-14:1 fatty acids as well as odd- and branched-chain fatty acids (13:0, iso 13:0, anteiso 13:0, 15:0, iso 15:0, and 17:0). There was also a tendency for 8:0 and 16:0 fatty acid concentrations to decrease when SFO was included in the cows´ diet. SFO decreased the concentration of 10:0 to 15:0 fatty acids in milk. The sum of the conjugated linoleic acids (CLAs), conjugated alpha-linolenic acid intermediates (CLnAs; 18:3 ω6 + 18:3 ω3), and 22:0 fatty acids in milk tended to increase, and there were significant increases in 18:0 and 9c11t-18:2 with SFO. In terms of the effects of SFO on the health-related lipid indices, the atherogenicity index tended to decrease and h/H tended to increase. When cows were supplemented with antioxidants, the concentration of 20:2 fatty acids decreased, the 6 + 7 + 8 + 9t-18:1, 16t-18:1, 20:0, 22:2, and 24:0 fatty acid concentrations increased, and there was a trend for the 22:1 ω9 fatty acid concentration to increase with antioxidants plus oil. There was a tendency for ω6 fatty acids and ω6/ω3 to increase with milk treated with antioxidants plus oil. The oxidative stability of milk was not influenced by the presence of SFO or antioxidants in the diet of dairy cows. Consumers desired the color and mouthfeel of the milk that was treated with SFO. Cows fed with 4% sunflower oil produced milk with an improved fatty acid profile for human nutrition, containing a higher CLA content and an improved ratio of hypocholesterolemic and hypercholesterolemic fatty acids, without increasing the milk's susceptibility to oxidation. The milk was also rated as being more acceptable by consumers.

Dual Emitter Nano-Electrospray Ionization Coupled to Differential Ion Mobility Spectrometry-Mass Spectrometry for Shotgun Lipidomics

Current lipidomics workflows are centered around acquisition of large data sets followed by lengthy data processing. A dual nESI-DIMS-MS platform was developed to perform real-time relative quantification between samples, providing data required for biomarker discovery and validation more quickly than traditional ESI-MS approaches. Nanosprayer activity and DIMS compensation field settings were controlled by a LabVIEW program synced to the accumulation portion of the ion trap scan function, allowing for full integration of the platform with a commercial mass spectrometer. By comparing samples with short electrospray pulses rather than constant electrospray, the DIMS and MS performance is normalized within an experiment, as signals are compared between individual mass spectra (ms time scale) rather than individual experiments (min-hr time scale). The platform was validated with lipid standards and extracts from nitrogen-deprived microalgae. Dual nESI-DIMS requires minimal system modification and is compatible with all traditional ion activation techniques and mass analyzers, making it a versatile improvement to shotgun lipidomics workflows.

Anti-obesity effect of a traditional Chinese dietary habit-blending lard with vegetable oil while cooking

Obesity, which is associated with dietary habits, has become a global social problem and causes many metabolic diseases. In China, both percentages of adult obesity and overweight are far lower compared to western countries. It was designed to increase the two levels of daily intake in human, namely 3.8% and 6.5%, which are recommendatory intake (25 g/d) and Chinese citizens’ practical intake (41.4 g/d), respectively. The mice were respectively fed with feeds added with soybean oil, lard or the oil blended by both for 12 weeks. In the mice fed with diet containing 3.8% of the three oils or 6.5% blended oil, their body weight, body fat rate, cross-sectional area of adipocytes, adipogenesis and lipogenesis in adipose were decreased, whereas hydrolysis of triglyserides in adipose was increased. This study demonstrated that the oil mixture containing lard and soybean oil had a remarkable anti-obesity effect. It suggests that the traditional Chinese dietary habits using oils blended with lard and soybean oil, might be one of the factors of lower percentages of overweight and obesity in China, and that the increasing of dietary oil intake and the changing of its component resulted in the increasing of obesity rate in China over the past decades.

Lipidomics to investigate the pharmacologic mechanisms of ginkgo folium in the hyperuricemic rat model

Hyperuricemia caused by purine metabolic abnormalities is reported to have close correlation with lipid metabolic disorders. Ginkgo folium, a frequently-used lipid-lowering medicine, has significant anti-hyperuricemia effects. However, it is poorly known about the interaction between lowering uric acid and regulation of lipid metabolic disorders. In this study, hyperuricemic rat model was induced by orally administration with fructose. Ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) combined with pattern recognition approaches were used to determine different lipid metabolites in serum of control group, model group, and different doses of ginkgo folium groups. Principal component analysis (PCA) was applied to analyze the MS data to assess the establishment of model, partial least squares-discriminate analysis (PLS-DA) and independent samples T-test were performed to indicate the differences between different groups of rats and to find biomarkers. Metabolomics pathway analysis (MetPA) was introduced to reveal the pharmacologic mechanisms of ginkgo folium. 19 potential biomarkers associated with hyperuricemia were found. After intervened by ginkgo folium, these biomarkers were returning to normal level. Among these biomarkers, 13 lipid biomarkers were significantly reversed. Ginkgo filum can lower uric acid via adjusting back the level of PCs and LPCs, which suggested that its treatment mechanisms may be related to reducing the activity of PLA2. In sum, the lipidomics analysis in the system level have enhanced our understanding to pathogenesis of hyperuricemia and the results suggested that ginkgo folium could alleviate the abnormal metabolic status of hyperuricemia. These results demonstrated a new mechanism for lowering uric acid, which was helpful to the early treatment for hyperuricemia.

Fatty acid profiling of blood cell membranes by gas chromatography with mass spectrometry

Fatty acids, which are well-known for their influence on human metabolism and signal transduction, are also a substantial component of cellular membranes and regulate the basic properties and functions of membranes. Owing to their multiple functions, fatty acid profiles of cell membranes are of great interest to those who are studying the relationship between membrane biochemical compositions and functions. A HCl-catalyzed derivation method and a gas chromatography with mass spectrometry analysis method were developed to accurately profile the fatty acids in cell membranes of erythrocytes, leukocytes, and platelets. The detection limits of all 35 fatty acids ranged from 0.58 to 22 ng/mL and the limits of quantitation were between 2.1 and 72 ng/mL. Finally, the established method was used to profile the membrane fatty acids of 44 healthy volunteers from the north and south of China. Results revealed significant differences in the fatty acid profiles from the two regions, particularly those of the erythrocytes. This technique may be applied to cell membrane studies to generate new biological hypotheses concerning fatty acid composition and membrane functions as well as to construct related disease profiles.

Applications of mass spectrometry for cellular lipid analysis

Mass spectrometric analysis of cellular lipids is an enabling technology for lipidomics, which is a rapidly-developing research field. In this review, we briefly discuss the principles, advantages, and possible limitations of electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) mass spectrometry-based methodologies for the analysis of lipid species. The applications of these methodologies to lipidomic research are also summarized.

Supplementation with a 9c,11t-rich conjugated linoleic acid blend shows no clear inhibitory effects on platelet function in healthy subjects at low and moderate cardiovascular risk: a randomized controlled trial

SCOPE

The 9cis,11trans-conjugated linoleic acid (9c,11t-CLA) is reported to have anti-atherogenic properties in animal models and to modulate protein expression in unstimulated human platelets in vivo. Platelet function was therefore investigated after dietary supplementation with 9c,11t-CLA enriched oil (CLA80:20) in a randomized, baseline-controlled cross-over trial.

METHODS AND RESULTS

Forty-three healthy adults at low to moderate risk of cardiovascular disease received 4 g/day of CLA80:20 or placebo for two weeks each. Platelet function, inflammation, and endothelial activation were assessed before and after each phase. Compared with placebo, supplementation had no significant effects on platelet function measured by Platelet Function Analyzer-100. Inhibitory effects on collagen-induced aggregation were sex-dependent (p = 0.005) that reached significance only in women (p = 0.045). Thrombin receptor-activating peptide (TRAP)-induced P-selectin expression was higher after supplementation in all subjects (p = 0.017). TRAP-induced platelet fibrinogen binding was also dependent on sex (p = 0.015), with fibrinogen binding after CLA80:20 being higher in males (p = 0.035). Plasma monocyte chemoattractant protein-1 was higher (p = 0.041) after CLA80:20.

CONCLUSION

No clear evidence was found for inhibition or activation of platelet function as well as inflammation by CLA80:20 in a low to moderate cardiovascular risk group.

The role of n - 6 and n - 3 polyunsaturated fatty acids in the manifestation of the metabolic syndrome in cardiovascular disease and non-alcoholic fatty liver disease

Cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD) are manifestations of the metabolic syndrome. CVD remains the number one cause of mortality in the West, while NAFLD is the most common liver disease. Growing evidence suggests that polyunsaturated fatty acids (PUFA) influence risk factors including circulating lipids and inflammation on the development of CVD and NAFLD. N - 6 and n - 3 PUFA are comprised of distinct family members, which are increasingly recognized for their individual effects. Therefore, this review examines what is currently known about the specific effects of the major n - 3 and n - 6 PUFA on CVD and NAFLD. Overall, this review supports a beneficial effect of n - 3 PUFA and highlights distinctive effects between alpha-linolenic acid found in plant oils relative to marine derived eicosapentaenoic acid and docosahexaenoic acid. This review also highlights contrasting health effects between the n - 6 PUFA, linoleic and arachidonic acid.

Natural forms of vitamin E: metabolism, antioxidant, and anti-inflammatory activities and their role in disease prevention and therapy

The vitamin E family consists of four tocopherols and four tocotrienols. α-Tocopherol (αT) is the predominant form of vitamin E in tissues and its deficiency leads to ataxia in humans. However, results from many clinical studies do not support a protective role of αT in disease prevention in people with adequate nutrient status. On the other hand, recent mechanistic studies indicate that other forms of vitamin E, such as γ-tocopherol (γT), δ-tocopherol, and γ-tocotrienol, have unique antioxidant and anti-inflammatory properties that are superior to those of αT in prevention and therapy against chronic diseases. These vitamin E forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids, and suppress proinflammatory signaling such as NF-κB and STAT3/6. Unlike αT, other vitamin E forms are significantly metabolized to carboxychromanols via cytochrome P450-initiated side-chain ω-oxidation. Long-chain carboxychromanols, especially 13'-carboxychromanols, are shown to have stronger anti-inflammatory effects than unmetabolized vitamins and may therefore contribute to the beneficial effects of vitamin E forms in vivo. Consistent with mechanistic findings, animal and human studies show that γT and tocotrienols may be useful against inflammation-associated diseases. This review focuses on non-αT forms of vitamin E with respect to their metabolism, anti-inflammatory effects and mechanisms, and in vivo efficacy in preclinical models as well as human clinical intervention studies.

Nutritional lipidomics: molecular metabolism, analytics, and diagnostics

The field of lipidomics is providing nutritional science a more comprehensive view of lipid intermediates. Lipidomics research takes advantage of the increase in accuracy and sensitivity of mass detection of MS with new bioinformatics toolsets to characterize the structures and abundances of complex lipids. Yet, translating lipidomics to practice via nutritional interventions is still in its infancy. No single instrumentation platform is able to solve the varying analytical challenges of the different molecular lipid species. Biochemical pathways of lipid metabolism remain incomplete and the tools to map lipid compositional data to pathways are still being assembled. Biology itself is dauntingly complex and simply separating biological structures remains a key challenge to lipidomics. Nonetheless, the strategy of combining tandem analytical methods to perform the sensitive, high-throughput, quantitative, and comprehensive analysis of lipid metabolites of very large numbers of molecules is poised to drive the field forward rapidly. Among the next steps for nutrition to understand the changes in structures, compositions, and function of lipid biomolecules in response to diet is to describe their distribution within discrete functional compartments lipoproteins. Additionally, lipidomics must tackle the task of assigning the functions of lipids as signaling molecules, nutrient sensors, and intermediates of metabolic pathways.

Body mass index and suicidal behaviors: a critical review of epidemiological evidence

INTRODUCTION

Obesity has been associated with an elevated risk of depression and other mental health symptoms. An increasing number of robust prospective studies, however, counter-intuitively and consistently suggested that body mass index (BMI) was inversely associated with the risk of completed suicide in a dose-response fashion. The current contribution appraised the epidemiological evidence and examined the nature of the purported relationship.

METHOD

We conducted a systematic review of English publications of original studies using the terms "obesity", "overweight", "body mass index", "BMI", "attempted suicide", "completed suicide", "suicide ideation", "suicidal behaviors" and "suicide". Data were extracted primarily through MEDLINE and PUBMED databases.

RESULTS

Almost all cohort studies reported an inverse relationship between BMI and the risk of completed suicide irrespective of region of origin and the gender of study participants. Overall, among men, a high BMI was associated with a low risk of attempted or completed suicide. There was a paradox among women, namely, a high BMI was associated with an elevated risk of attempted suicide but a low risk of completed suicide.

LIMITATIONS

As a narrative review, the current report was interpretive and qualitative in nature.

CONCLUSION

Consideration of observational data, methodological issues stemmed from the rarity of deaths by suicide, homogeneity of study populations, heterogeneity of suicide methods, and the corresponding neurobiological changes made interpretation difficult. Intercultural cohort observations across countries may help to weigh the contributions from biological and socio-cultural factors. The purported association not only represents a scientific challenge, it's also an opportunity potentially leading to important insights into prevention of suicide death.

Avocado consumption is associated with better diet quality and nutrient intake, and lower metabolic syndrome risk in US adults: results from the National Health and Nutrition Examination Survey (NHANES) 2001-2008

BACKGROUND

Avocados contain monounsaturated fatty acids (MUFA) dietary fiber, essential nutrients and phytochemicals. However, no epidemiologic data exist on their effects on diet quality, weight management and other metabolic disease risk factors. The objective of this research was to investigate the relationships between avocado consumption and overall diet quality, energy and nutrient intakes, physiological indicators of health, and risk of metabolic syndrome.

METHODS

Avocado consumption and nutrition data were based on 24-hour dietary recalls collected by trained NHANES interviewers using the USDA Automated Multiple Pass Method (AMPM). Physiological data were collected from physical examinations conducted in NHANES Mobile Examination Centers. Diet quality was calculated using the USDA's Healthy Eating Index-2005. Subjects included 17,567 US adults ≥ 19 years of age (49% female), including 347 avocado consumers (50% female), examined in NHANES 2001-2008. Least square means, standard errors, and ANOVA were determined using appropriate sample weights, with adjustments for age, gender, ethnicity, and other covariates depending on dependent variable of interest.

RESULTS

Avocado consumers had significantly higher intakes of vegetables (p<0.05); fruit, diet quality, total fat, monounsaturated and polyunsaturated fats, dietary fiber, vitamins E, K, magnesium, and potassium (p<0.0001); vitamin K (p=0.0013); and lower intakes of added sugars (p<0.0001). No significant differences were seen in calorie or sodium intakes. Body weight, BMI, and waist circumference were significantly lower (p<0.01), and HDL-C was higher (p<0.01) in avocado consumers. The odds ratio for metabolic syndrome was 50% (95th CI: 0.32-0.72) lower in avocado consumers vs. non-consumers.

CONCLUSIONS

Avocado consumption is associated with improved overall diet quality, nutrient intake, and reduced risk of metabolic syndrome. Dietitians should be aware of the beneficial associations between avocado intake, diet and health when making dietary recommendations.

Hepatic and plasma sex differences in saturated and monounsaturated fatty acids are associated with differences in expression of elongase 6, but not stearoyl-CoA desaturase in Sprague-Dawley rats

Monounsaturated fatty acids (MUFA) have been viewed as either beneficial or neutral with respect to health; however, recent evidence suggests that MUFA may be associated with obesity and cardiovascular disease. Sex differences in MUFA composition have been reported in both rats and humans, but the basis for this sexual dimorphism is unknown. In the current study, enzymes involved in MUFA biosynthesis are examined in rat and cell culture models. Male and female rats were maintained on an AIN-93G diet prior to killing at 14 weeks of age after an overnight fast. Concentrations of 16:0 (2,757 ± 616 vs. 3,515 ± 196 μg fatty acid/g liver in males), 18:1n-7 (293 ± 66 vs. 527 ± 49 μg/g) and 18:1n-9 (390 ± 80 vs. 546 ± 47 μg/g) were lower, and concentrations of 18:0 (5,943 ± 1,429 vs. 3,987 ± 325 μg/g) were higher in phospholipids in livers from female rats compared with males. Hepatic elongase 6 mRNA and protein were 5.9- and 2.0-fold higher, respectively, in females compared with males. Stearoyl-CoA desaturase expression did not differ. Specific hormonal effects were examined in HepG2 cells cultured with varying concentrations of 17β-estradiol, progesterone and testosterone (0, 10, 30 and 100 nM) for 72 h. Progesterone and 17β-estradiol treatments increased, while testosterone decreased, elongase 6 protein. Sex differences in MUFA composition were associated with increased expression of hepatic elongase 6 in females relative to male rats, which appears to be mediated by sex hormones based on observations of hormonal treatments of HepG2 cells.

Decreased plasma cholesterol concentrations after PUFA-rich diets are not due to reduced cholesterol absorption/synthesis

Plasma cholesterol concentrations increase with consumption of high saturated fatty acid (SFA) and decrease with high polyunsaturated fatty acid (PUFA) diets, leading to shifts in lipid levels consistent with reduction in heart disease risk. Direct measurements of cholesterol absorption, one of the key regulators of plasma cholesterol levels, have not been performed in humans after consumption of high PUFA diets. Thus, cholesterol absorption and fractional synthesis rates (FSRs) were measured in 16 healthy adults (8 males and 9 females) using a randomized cross-over study with a diet containing high (PUFA/SFA) P/S ratio (2:1) and a low P/S ratio (0.5:1). Cholesterol absorption and fractional cholesterol synthetic rates were measured using stable isotopes after 20 days of dietary intervention. Diet did not affect cholesterol absorption or synthesis. There was a significant decrease in plasma cholesterol concentrations (P < 0.02), specifically LDL-cholesterol (P < 0.02), without a change in HDL-cholesterol or triacylglycerol concentrations. Intraluminal cholesterol solubilization and plasma sterol (cholesterol biosynthetic intermediates and plant sterols) levels were not affected by diet. Thus, consumption of diets with a high P/S ratio reduces plasma total and LDL-cholesterol concentrations independent of shifts in cholesterol absorption or synthesis.

Effects of live Lactobacillus paracasei on plasma lipid concentration in rats fed an ethanol-containing diet

The protective effects of live Lactobacillus paracasei NFRI 7415 on alcoholic liver disease were investigated. Male Fischer 344 rats were fed a control diet (CD), an ethanol diet (ED) (35.8% of total energy from ethanol), or an ethanol diet containing 20% live Lb. paracasei NFRI 7415 (10(7) cfu/g) (LD) for 10 weeks. The results indicated that live Lb. paracasei NFRI 7415 reduced the total cholesterol concentration of the plasma and liver in the rats fed the LD. The level of docosahexaenoic acid (DHA; 22:6n-3) in the plasma and liver of the LD group was higher than in the ED group. Chronic alcohol consumption decreased the level of n-3 fatty acid in the plasma and liver of the ED group. These results indicated that live Lb. paracasei NFRI 7415 can adjust the fatty acid composition of the plasma and liver, and that it is possible to decrease liver damage due to chronic alcohol intake.

Genetic variation in fatty acid elongases is not associated with intermediate cardiovascular phenotypes or myocardial infarction

BACKGROUND/OBJECTIVES

Elongases 2, 4 and 5, encoded by genes ELOVL2, ELOVL4 and ELOVL5, have a key role in the biosynthesis of very long chain polyunsaturated fatty acids (PUFAs). To date, few studies have investigated the associations between elongase polymorphisms and cardiovascular health. We investigated whether ELOVL polymorphisms are associated with adipose tissue fatty acids, serum lipids, inflammation and ultimately with nonfatal myocardial infarction (MI) in a Costa Rican population.

SUBJECTS/METHODS

MI cases (n=1650) were matched to population-based controls (n=1650) on age, sex and area of residence. Generalized linear and multiple conditional logistic regression models were used to assess the associations between seven common ELOVL polymorphisms and cardiometabolic outcomes. Analyses were replicated in The Nurses' Health Study (n=1200) and The Health Professionals Follow-Up Study (n=1295).

RESULTS

Variation in ELOVL2, ELOVL4 and ELOVL5 was not associated with adipose tissue fatty acids, intermediate cardiovascular risk factors or MI. In the Costa Rica study, the number of the minor allele copies at rs2294867, located in the ELOVL5 gene, was associated with an increase in total and LDL cholesterol (adjusted P-values=0.001 and <0.0001 respectively). Additionally, the number of the minor allele copies at rs761179, also located in the ELOVL5 gene, was significantly associated with an increase in total cholesterol (adjusted P-value=0.04). However, the observed associations were not replicated in independent populations.

CONCLUSION

Common genetic variants in elongases are not associated with adipose tissue fatty acids, serum lipids, biomarkers of systemic inflammation, or the risk of MI.

Toxicity of fatty acids on ECV-304 endothelial cells

The effects of stearic (saturated) or oleic (monounsaturated) acids and their combination with ω-3 and ω-6 polyunsaturated fatty acids (PUFA) on death of endothelial cells (ECV-304 cell line) were investigated. We examined: loss of plasma membrane integrity, DNA fragmentation, accumulation of neutral lipids (NL) and release of reactive oxygen species (ROS). The fatty acids studied were: stearic (SA), oleic (OA), docosahexaenoic (DHA), eicosapentaenoic (EPA), linoleic (LA) and gamma-linolenic (γA) acids. SA at 150 μM induced cell death, did not lead to accumulation of NL and raised the release of ROS. ω-3 PUFA decreased ROS production, increased NL content but did not protect against ECV-304 cell death induced by SA. ω-6 PUFA inhibited SA-induced cell death, increased NL content and decreased ROS production. OA caused cell death but did not increase NL content and ROS production even at 300 μM. ω-3 and ω-6 FA associated with OA further increased cell death with no change in ROS production and NL content. Concluding, ω-6 PUFA had a greater protective effect than ω-3 PUFA on the deleterious effects caused by SA whereas OA had low cytotoxicity but, when associated with PUFA, presented marked toxic effects on ECV-304 endothelial cells.

Feeding the world healthily: the challenge of measuring the effects of agriculture on health

Agricultural production, food systems and population health are intimately linked. While there is a strong evidence base to inform our knowledge of what constitutes a healthy human diet, we know little about actual food production or consumption in many populations and how developments in the food and agricultural system will affect dietary intake patterns and health. The paucity of information on food production and consumption is arguably most acute in low- and middle-income countries, where it is most urgently needed to monitor levels of under-nutrition, the health impacts of rapid dietary transition and the increasing 'double burden' of nutrition-related disease. Food availability statistics based on food commodity production data are currently widely used as a proxy measure of national-level food consumption, but using data from the UK and Mexico we highlight the potential pitfalls of this approach. Despite limited resources for data collection, better systems of measurement are possible. Important drivers to improve collection systems may include efforts to meet international development goals and partnership with the private sector. A clearer understanding of the links between the agriculture and food system and population health will ensure that health becomes a critical driver of agricultural change.

Dairy products and plasma cholesterol levels

Cholesterol synthesized in the body or ingested is an essential lipid component for human survival from our earliest life. Newborns ingest about 3-4 times the amount per body weight through mother's milk compared to the dietary intake of adults. A birth level of 1.7 mmol/L plasma total cholesterol will increase to 4-4.5 mmol/L during the nursing period and continue to increase from adulthood around 40% throughout life. Coronary artery disease and other metabolic disorders are strongly associated with low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol as well as triacylglycerol concentration. Milk fat contains a broad range of fatty acids and some have a negative impact on the cholesterol rich lipoproteins. The saturated fatty acids (SFAs), such as palmitic acid (C16:0), myristic acid (C14:0), and lauric acid (C12:0), increase total plasma cholesterol, especially LDL, and constitute 11.3 g/L of bovine milk, which is 44.8% of total fatty acid in milk fat. Replacement of dairy SFA and trans-fatty acids with polyunsaturated fatty acids decreases plasma cholesterol, especially LDL cholesterol, and is associated with a reduced risk of cardiovascular disease. Available data shows different effects on lipoproteins for different dairy products and there is uncertainty as to the impact a reasonable intake amount of dairy items has on cardiovascular risk. The aim of this review is to elucidate the effect of milk components and dairy products on total cholesterol, LDL, HDL, and the LDL/HDL quotients. Based on eight recent randomized control trials of parallel or cross-over design and recent reviews it can be concluded that replacement of saturated fat mainly (but not exclusively) derived from high-fat dairy products with low-fat dairy products lowers LDL/HDL cholesterol and total/HDL cholesterol ratios. Whey, dairy fractions enriched in polar lipids, and techniques such as fermentation, or fortification of cows feeding can be used to produce dairy products with more beneficial effects on plasma lipid profile.

Dairy food consumption and obesity-related chronic disease

Dairy food comprises a range of different products with varying nutritional components. In the context of a healthy diet, dairy food may provide protection against and amelioration of chronic diseases related to obesity. These include overweight, insulin resistance/metabolic syndrome/type 2 diabetes, hypertension/stroke, and cardiovascular disease. Eliciting how dairy food may have this impact represents a challenge for modern nutritional science and requires an integration of knowledge from observational studies of population dietary patterns and disease prevalence, and experimental studies testing the effect of dairy food consumption. It also benefits from the recent identification of biomarkers of dairy fat intake and from mechanistic studies that support the plausibility of the observed effects. Future research might discriminate between types of dairy foods and focus on the synergy provided by the food matrix, rather than simply the component parts of the food.

Genetic variation in lipid desaturases and its impact on the development of human disease

Perturbations in lipid metabolism characterize many of the chronic diseases currently plaguing our society, such as obesity, diabetes, and cardiovascular disease. Thus interventions that target plasma lipid levels remain a primary goal to manage these diseases. The determinants of plasma lipid levels are multi-factorial, consisting of both genetic and lifestyle components. Recent evidence indicates that fatty acid desaturases have an important role in defining plasma and tissue lipid profiles. This review will highlight the current state-of-knowledge regarding three desaturases (Scd-1, Fads1 and Fads2) and their potential roles in disease onset and development. Although research in rodent models has provided invaluable insight into the regulation and functions of these desaturases, the extent to which murine research can be translated to humans remains unclear. Evidence emerging from human-based research demonstrates that genetic variation in human desaturase genes affects enzyme activity and, consequently, disease risk factors. Moreover, this genetic variation may have a trans-generational effect via breastfeeding. Therefore inter-individual variation in desaturase function is attributed to both genetic and lifestyle components. As such, population-based research regarding the role of desaturases on disease risk is challenged by this complex gene-lifestyle paradigm. Unravelling the contribution of each component is paramount for understanding the inter-individual variation that exists in plasma lipid profiles, and will provide crucial information to develop personalized strategies to improve health management.

Dietary arachidonic acid to EPA and DHA balance is increased among Canadian pregnant women with low fish intake

Arachidonic [ARA, 20:4(n-6)], eicosapentaenoic [EPA, 20:5(n-3)], and docosahexaenoic acids [DHA, 22:6(n-3)] occur in the diet in animal tissue lipids, play important roles in human development and health, but have interactive and opposing functions. Meat and poultry have higher ARA and fish are richer in EPA and DHA. National databases were recently revised to include complete data on ARA in foods. We used a validated FFQ and the revised nutrient databases to quantify the distribution of ARA, EPA, and DHA intakes and balance for 204 healthy Canadian pregnant women. We focused on intake distributions because risk of adverse health effects increases at lower nutrient intakes. RBC fatty acids were analyzed concurrenly with dietary assessment. The distribution of ARA, EPA, and DHA intakes were skewed (P < 0.001), with a median (5-95th percentile) of 107 (41-225), 65 (10-228), and 105 (10-430) mg/d ARA, EPA, and DHA, respectively. Fish provided 66 and 76% of EPA and DHA, respectively, whereas eggs, poultry, and meats provided 81% of ARA. Women consuming <101 g fish/wk consumed less EPA and DHA and had markedly elevated median dietary ARA:EPA and ARA:DHA ratios and RBC lipid ARA:EPA + DHA ratios compared with women consuming >or=101 g fish/wk (P < 0.001). Relatively small increases in fish intake of 1-2 servings (25-50 g)/wk corrected the distorted dietary (n-6):(n-3) fatty acid balance among women consuming meats, but not fish. Median fish and DHA intakes below the recommended 1-2 servings/wk fish for pregnant women suggest major changes in the availability, cost, or acceptance of fish are needed.