Trans fatty acids: effects on metabolic syndrome, heart disease and diabetes

Plasma trans-fatty acid concentrations continue to be associated with metabolic syndrome among US adults after reductions in trans-fatty acid intake

No study examined and compared the association between intake of trans-fatty acids (TFAs) and risk of metabolic syndrome before and after significant reduction of TFA intakes in the US population. We hypothesized that the relationship might remain significant after substantial reduction of TFA intakes in the population. We used data on 1442 and 2233 adults aged ≥20 years from the National Health and Nutrition Examination Survey 1999-2000 and 2009-2010, respectively. Multivariable logistic regression analysis was used to assess the association between plasma TFA concentrations and metabolic syndrome, including each of its 5 components. The median plasma TFA concentrations were reduced from 79.8 μmol/L in 1999-2000 to 36.9 μmol/L in 2009-2010. The fully adjusted prevalence ratios comparing the highest vs the lowest quintile of plasma TFA concentrations in 1999-2000 were 3.43 (95% confidence interval, 2.39-4.92) for metabolic syndrome, 1.72 (1.38-2.14) for large waistline, 8.25 (6.34-10.74) for high triglycerides, 1.96 (1.46-2.62) for low high-density lipoprotein cholesterol, 1.14 (0.85-1.55) for high blood pressure, and 1.48 (1.19-1.85) for high fasting glucose, respectively. The corresponding prevalence ratios in 2009-2010 were 2.93 (2.41-3.54), 1.62 (1.39-1.89), 14.93 (9.28-24.02), 3.09 (2.18-4.37), 1.27 (1.11-1.46), and 1.24 (1.06-1.46), respectively. The pattern of association between TFAs and metabolic syndrome and its components did not differ by cycles. The observed associations were consistent across the subgroups examined. Despite a 54% decline in plasma TFA concentrations from 1999-2000 to 2009-2010, it was positively associated with risk of metabolic syndrome and its individual components except for blood pressure in 1999-2000. Our findings support Food and Drug Administration initiatives to remove TFAs from the industrially-produced foods.

Plasma trans-Fatty Acid Concentrations Continue to Be Associated with Serum Lipid and Lipoprotein Concentrations among US Adults after Reductions in trans-Fatty Acid Intake

Background: High intakes of trans-fatty acids (TFAs), especially industrially produced TFAs, can lead to unfavorable lipid and lipoprotein concentrations and an increased risk of cardiovascular disease. It is unknown how this relation might change in a population after significant reductions in TFA intake.Objective: This study, which used a new analytical method for measuring plasma TFA concentrations, clarified the association between plasma TFA and serum lipid and lipoprotein concentrations before and after the US FDA enacted TFA food-labeling regulations in 2006.Methods: Data were selected from the NHANES of 1999-2000 and 2009-2010. Findings on 1383 and 2155 adults, respectively, aged ≥20 y, were evaluated. Multivariable linear regressions were used to examine the associations between plasma TFA concentration and lipid and lipoprotein concentrations. The outcome measures were serum concentrations of total cholesterol (TC), LDL cholesterol, HDL cholesterol, and triglycerides and the ratio of TC to HDL cholesterol.Results: The median plasma TFA concentration decreased from 80.6 μmol/L in 1999-2000 to 37.0 μmol/L in 2009-2010. Plasma TFA concentration continued to be associated with serum lipid and lipoprotein concentrations after significant reductions in TFA intake in the population. For example, by comparing the lowest with the highest quintiles of TFA concentration in 1999-2000, adjusted mean (95% CI) LDL-cholesterol concentrations increased from 118 mg/dL (112, 123 mg/dL) to 135 mg/dL (130, 141 mg/dL) (P-trend < 0.001). The corresponding values for 2009-2010 were 102 mg/dL (97.4, 107 mg/dL) and 129 mg/dL (125, 133 mg/dL) for LDL cholesterol (P-trend < 0.001). Differences between the highest and lowest quintiles were consistent across age groups, sexes, races/ethnicities, and other covariates.Conclusions: Despite a 54% reduction in plasma TFA concentrations in US adults from 1999-2000 to 2009-2010, concentrations remained significantly associated with serum lipid and lipoprotein concentrations. There does not appear to be a threshold under which the association between plasma TFA concentration and lipid profiles might become undetectable.

Actions and Mechanisms of Polyunsaturated Fatty Acids on Voltage-Gated Ion Channels

Polyunsaturated fatty acids (PUFAs) act on most ion channels, thereby having significant physiological and pharmacological effects. In this review we summarize data from numerous PUFAs on voltage-gated ion channels containing one or several voltage-sensor domains, such as voltage-gated sodium (Na_V), potassium (K_V), calcium (Ca_V), and proton (H_V) channels, as well as calcium-activated potassium (K_Ca), and transient receptor potential (TRP) channels. Some effects of fatty acids appear to be channel specific, whereas others seem to be more general. Common features for the fatty acids to act on the ion channels are at least two double bonds in cis geometry and a charged carboxyl group. In total we identify and label five different sites for the PUFAs. PUFA site 1: The intracellular cavity. Binding of PUFA reduces the current, sometimes as a time-dependent block, inducing an apparent inactivation. PUFA site 2: The extracellular entrance to the pore. Binding leads to a block of the channel. PUFA site 3: The intracellular gate. Binding to this site can bend the gate open and increase the current. PUFA site 4: The interface between the extracellular leaflet of the lipid bilayer and the voltage-sensor domain. Binding to this site leads to an opening of the channel via an electrostatic attraction between the negatively charged PUFA and the positively charged voltage sensor. PUFA site 5: The interface between the extracellular leaflet of the lipid bilayer and the pore domain. Binding to this site affects slow inactivation. This mapping of functional PUFA sites can form the basis for physiological and pharmacological modifications of voltage-gated ion channels.

Trans-Fatty Acid-Stimulated Mammary Gland Growth in Ovariectomized Mice is Fatty Acid Type and Isomer Specific

We previously reported that the trans-18:2 fatty acid trans-10, cis-12 conjugated linoleic acid (t10,c12-CLA) stimulates mammary gland development independent of estrogen and its receptor. Given the negative consequences of dietary trans-fatty acids on various aspects of human health, we sought to establish whether other trans-fatty acids could similarly induce ovary-independent mammary gland growth in mice. Prepubertal BALB/cJ mice were ovariectomized at 21 days of age then were fed diets enriched with cis-9, trans-11 CLA (c9,t11-CLA), or mixtures of trans-18:1 fatty acids supplied by partially hydrogenated sunflower, safflower, or linseed oil. The resultant mammary phenotype was evaluated 3 weeks later and compared to the growth response elicited by t10,c12-CLA, or the defined control diet. Whereas partially hydrogenated safflower oil increased mammary gland weight, none of the partially hydrogenated vegetable oils promoted mammary ductal growth. Similarly, the c9,t11-CLA supplemented diet was without effect on mammary development. Taken together, our data emphasize a unique effect of t10,c12-CLA in stimulating estrogen-independent mammary gland growth manifest as increased mammary ductal area and elongation that was not recapitulated by c9,t11-CLA or the partially hydrogenated vegetable oil diets.

PPARα protects against trans-fatty-acid-containing diet-induced steatohepatitis

Consumption of trans-fatty acids (TFA), unsaturated fatty acids (FA) containing trans double bonds, is a risk factor for metabolic syndrome and steatohepatitis. Peroxisome proliferator-activated receptor α (PPARα) is a master regulator of hepatic lipid homeostasis. To examine the contribution of PPARα to changes in liver phenotypes induced by TFA, two diets were used: a purified control diet and an isocaloric diet in which most of the soybean oil, a major source of FA in the diet, was replaced with TFA-rich shortening. The diets were fed to wild-type and Ppara-null mice for 2 months. Ppara-null mice fed a TFA-containing diet showed more severe hepatic steatosis and liver damage compared with similarly treated wild-type mice, as revealed by increased hepatic triglyceride (TG) contents and serum alanine aminotransferase activities. While the TFA-rich diet increased the hepatic expression of enzymes involved in de novo FA synthesis and decreased TG-hydrolyzing enzymes in both genotypes, the expression of FA-catabolizing enzymes was decreased in Ppara-null mice, resulting in more severe hepatosteatosis. Additionally, the expression levels of key contributors to inflammation, such as osteopontin, were increased, and nuclear factor-kappa B was activated in TFA-containing diet-fed Ppara-null mice. Enhanced inflammatory signaling in these mice was presumably mediated by toll-like receptor 2, with no accompanying inflammasome activation. Collectively, these results suggest a protective role for PPARα in the pathological changes in the liver following TFA consumption. PPARα might prevent TFA-containing diet-induced steatohepatitis.

The proportion of total C18:1 trans-fatty acids in red blood cell membranes relates to carotid plaque prevalence

Consistent evidence supports the pro-atherogenic properties of dietary trans-fatty acids (TFAs). However, there are no clinical data on TFA intake and atheroma plaque. We cross sectionally investigated whether the proportion of total C18:1 TFA in red blood cells (RBCs), which mirrors dietary TFA intake, independently relates to carotid plaque prevalence in subjects with new-onset type 2 diabetes mellitus without prior cardiovascular disease (n=101, 56% men, mean age 61 years) and age- and sex-matched controls (n=96). RBC fatty acid composition was determined by gas chromatography. Plaque (defined as carotid intima-media thickness ≥1.5 mm) was sonographically assessed at three bilateral carotid segments. In multivariate models adjusting for group (diabetes or control) and classical cardiovascular risk factors, for each 0.1% increase in RBC total C18:1 TFA isomers, plaque prevalence increased by 53% (P=.002). In contrast, for each 0.1% increase in RBC alpha-linolenic acid, the vegetable omega-3 fatty acid, plaque prevalence decreased by 43% (P<.001). We conclude that the RBC membrane proportion of total C18:1 TFA, considered a proxy of intake, directly relates to the ultrasound feature that best predicts future cardiovascular events. Our findings support current recommendations to limit TFA intake for cardiovascular health promotion.

Trans 18-carbon monoenoic fatty acid has distinct effects from its isomeric cis fatty acid on lipotoxicity and gene expression in Saccharomyces cerevisiae

Epidemiological studies have suggested that an excess intake of trans-unsaturated fatty acids increases the risk of coronary heart disease. However, the mechanisms of action of trans-unsaturated fatty acids in eukaryotic cells remain unclear. Since the budding yeast Saccharomyces cerevisiae can grow using fatty acids as the sole carbon source, it is a simple and suitable model organism for understanding the effects of trans-unsaturated fatty acids at the molecular and cellular levels. In this study, we compared the physiological effects of Δ9 cis and trans 18-carbon monoenoic fatty acids (oleic acid and elaidic acid) in yeast cells. The results obtained revealed that the two types have distinct effects on the expression of OLE1, which encodes Δ9 desaturase, and lipotoxicity in are1Δare2Δdga1Δlro1Δ and gat1Δ cells. Our results suggest that cis and trans 18-carbon monoenoic fatty acids exert different physiological effects in the regulation of gene expression and processing of excess fatty acids in yeast.

Urbanized South Asians' susceptibility to coronary heart disease: The high-heat food preparation hypothesis

OBJECTIVE

Known risk factors do not fully explain the comparatively high susceptibility to coronary heart disease (CHD) in South Asians (Indian, Pakistani, Bangladeshi, and Sri Lankan populations in South Asia and overseas). The search for explanatory hypotheses and cofactors that raise susceptibility of South Asians to CHD continues. The aim of this study was to propose "the high-heat food preparation hypothesis," where neo-formed contaminants (NFCs) such as trans-fatty acids (TFAs) and advanced glycation end-products (AGEs) are the cofactors.

METHODS

We reviewed the actions of AGEs and TFAs, the burden of these products in tissues and blood in South Asians, the relationship between these products and CHD, the effects of preparing food and reheating oils at high temperatures on NFCs, and the foods and mode of preparation in South Asian and Chinese cuisines.

RESULTS

Animal and human studies show NFCs increase the risk for CHD. Evidence on the consumption and body burden of these products across ethnic groups is not available, and comparable data on the NFC content of the cuisine of South Asians and potential comparison populations (e.g., the Chinese with lower CHD rates) are limited. South Asians' cuisine is dominated by frying and roasting techniques that use high temperatures. South Asian foods have high TFA content primarily through the use of partially hydrogenated fats, reheated oils, and high-heat cooking. Reheating oils greatly increases the TFA content. In comparison, Chinese cuisine involves mostly braising, steaming, and boiling rather than frying.

CONCLUSION

We hypothesize that South Asians' susceptibility to CHD is partly attributable to high-heat treated foods producing high NFCs. Research to accrue direct evidence is proposed.

Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation

Heating/frying and reuse of edible fats/oils induces chemical changes such as formation of trans fatty acids (TFAs). The aim of this study was to investigate the effect of heating/frying on formation of TFAs in fats/oils. Using gas chromatography with flame ionisation detector, TFA was estimated in six commonly used fat/oils in India (refined soybean oil, groundnut oil, olive oil, rapeseed oil, clarified butter, partially hydrogenated vegetable oil), before and after subjecting them to heating/frying at 180°C and 220°C. All six fats/oils subjected to heating/frying demonstrated an increase in TFAs (p<0.001), saturated fatty acids (p<0.001) and decrease in cis-unsaturated fatty acids (p<0.001). The absolute increase in TFA content of edible oils (after subjecting to heating/reheating) ranged between 2.30±0.89g/100g and 4.5±1.43g/100g; amongst edible fats it ranged between 2.60±0.38g/100g and 5.96±1.94g/100g. There were no significant differences between the two treatment groups (heating and frying; p=0.892). Considering the undesirable health effects of TFA, appropriate guidelines for heating/re-frying of edible fats/oils by Asian Indians should be devised.

Are Chinese edible oils safe? A survey of trans fatty acid contents in Chinese edible oils

Nine different edible oil types from 7 cities in China were analyzed. Trans fatty acid (TFA) contents in edible oils were determined, TFA distribution characteristics were analyzed, and a risk assessment was performed. Total TFA contents varied from 0.075±0.011 to 2.243±0.770 g/100 g of oil, with a mean content of 0.66 g/100 g of oil. TFA contents differed among different oil types and among different cities. Generally speaking, oil samples from northern areas of China contained more TFA, and lard usually had higher levels of TFA than other oils. An exposure assessment showed that the estimated daily intake of TFA from Chinese edible oils was low, and a risk assessment indicated that there was a low risk for TFA consumption in Chinese edible oils.

Dietary Fatty Acids and Their Potential for Controlling Metabolic Diseases Through Activation of FFA4/GPR120

It is well known that the amount and type of ingested fat impacts the development of obesity and metabolic diseases, but the potential for beneficial effects from fat has received less attention. It is becoming clear that the composition of the individual fatty acids in diet is important. Besides acting as precursors of potent signaling molecules, dietary fatty acids act directly on intracellular and cell surface receptors. The free fatty acid receptor 4 (FFA4, previously GPR120) is linked to the regulation of body weight, inflammation, and insulin resistance and represents a potential target for the treatment of metabolic disorders, including type 2 diabetes and obesity. In this review, we discuss the various types of dietary fatty acids, the link between FFA4 and metabolic diseases, the potential effects of the individual fatty acids on health, and the ability of fatty acids to activate FFA4. We also discuss the possibility of dietary schemes that implement activation of FFA4.

Elaidate, an 18-carbon trans-monoenoic fatty acid, but not physiological fatty acids increases intracellular Zn(2+) in human macrophages

Artificial trans fatty acids promote atherosclerosis by blocking macrophage clearance of cell debris. Classical fatty-acid response mechanisms include TLR4-NF-κB activation, and Erk1/2 phosphorylation, but these may not indicate long-term mechanisms. Indeed, nuclear NF-κB was increased by 60 min treatment by 30 μM of the 18 carbon trans unsaturated fatty acid elaidic acid (elaidate), the physiological cis-unsaturated fatty acid oleic acid (oleate), and the 18 or 16 carbon saturated fatty acids stearic and palmitic acid (stearate or palmitate). However, except for stearate, effects on related pathways were minimal at 44 h. To determine longer term effects of trans fatty acids, we compared mRNA expression profiles of (trans) elaidate to (cis) oleate, 30 μM, at 44 h in human macrophages. We found that elaidate changed Zn(2+) -homeostasis gene mRNAs markedly. This might be important because Zn(2+) is a major regulator of macrophage activity. Messenger RNAs of seven Zn(2+) -binding metallothioneins decreased 2-4-fold; the zinc importer SLC39A10 increased twofold, in elaidate relative to oleate-treated cells. Results were followed by quantitative PCR comparing cis, trans, and saturated fatty acid effects on Zn(2+) -homeostasis gene mRNAs. This confirmed that elaidate uniquely decreased metallothionein expression and increased SLC39A10 at 44 h. Further, intracellular Zn(2+) was measured using N-(carboxymethyl)-N-[2-[2-[2(carboxymethyl) amino]-5-(2,7,-difluoro-6-hydroxy-3-oxo-3H-xanthen-9-yl)-phenoxy]-ethoxy]-4-methoxyphenyl]glycine, acetoxymethyl ester (FluoZin-3-AM). This showed that, at 44 h, only cells treated with elaidate had increased Zn(2+) . The durable effect of elaidate on Zn(2+) activation is a novel and specific effect of trans fatty acids on peripheral macrophage metabolism.

Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: A Comprehensive Review

Suboptimal nutrition is a leading cause of poor health. Nutrition and policy science have advanced rapidly, creating confusion yet also providing powerful opportunities to reduce the adverse health and economic impacts of poor diets. This review considers the history, new evidence, controversies, and corresponding lessons for modern dietary and policy priorities for cardiovascular diseases, obesity, and diabetes mellitus. Major identified themes include the importance of evaluating the full diversity of diet-related risk pathways, not only blood lipids or obesity; focusing on foods and overall diet patterns, rather than single isolated nutrients; recognizing the complex influences of different foods on long-term weight regulation, rather than simply counting calories; and characterizing and implementing evidence-based strategies, including policy approaches, for lifestyle change. Evidence-informed dietary priorities include increased fruits, nonstarchy vegetables, nuts, legumes, fish, vegetable oils, yogurt, and minimally processed whole grains; and fewer red meats, processed (eg, sodium-preserved) meats, and foods rich in refined grains, starch, added sugars, salt, and trans fat. More investigation is needed on the cardiometabolic effects of phenolics, dairy fat, probiotics, fermentation, coffee, tea, cocoa, eggs, specific vegetable and tropical oils, vitamin D, individual fatty acids, and diet-microbiome interactions. Little evidence to date supports the cardiometabolic relevance of other popular priorities: eg, local, organic, grass-fed, farmed/wild, or non-genetically modified. Evidence-based personalized nutrition appears to depend more on nongenetic characteristics (eg, physical activity, abdominal adiposity, gender, socioeconomic status, culture) than genetic factors. Food choices must be strongly supported by clinical behavior change efforts, health systems reforms, novel technologies, and robust policy strategies targeting economic incentives, schools and workplaces, neighborhood environments, and the food system. Scientific advances provide crucial new insights on optimal targets and best practices to reduce the burdens of diet-related cardiometabolic diseases.

[Nutritional therapy in the obese patient with insulin resistance and cardiovascular risk]

Currently, each of the different scientific societies advocate one kind or another nutritional recommendations for patients with vascular risk. This variety of diets on the one hand enrich the nutritional therapeutic possibilities, but on the other can lead to some confusion, both for the patient and for the professional that advises. Furthermore, most studies assessing vascular risk mention a "diet" without defining or specifying to which kind of diet they refer, thereby introducing an important bias in the results of those studies. In fact, some of them bear a degree of contradiction. This review aims to shed some light on such a controversial topic.

Fermentation of bioactive solid lipid nanoparticles by human gut microflora

Solid lipid nanoparticles (SLNs) can be used for oral delivery of phenolic compounds in order to protect them from the harsh conditions of digestion and improve their bioavailability in the intestinal epithelium.

Current Evidence Supporting the Link Between Dietary Fatty Acids and Cardiovascular Disease

Lack of consensus exists pertaining to the scientific evidence regarding effects of various dietary fatty acids on cardiovascular disease (CVD) risk. The objective of this article is to review current evidence concerning cardiovascular health effects of the main dietary fatty acid types; namely, trans (TFA), saturated (SFA), polyunsaturated (PUFA; n-3 PUFA and n-6 PUFA), and monounsaturated fatty acids (MUFA). Accumulating evidence shows negative health impacts of TFA and SFA; both may increase CVD risk. Policies have been proposed to reduce TFA and SFA consumption to less than 1 and 7 % of energy intake, respectively. Cardiovascular health might be promoted by replacing SFA and TFA with n-6 PUFA, n-3 PUFA, or MUFA; however, the optimal amount of PUFA or MUFA that can be used to replace SFA and TFA has not been defined yet. Evidence suggests of the potential importance of restricting n-6 PUFA up to 10 % of energy and obtaining an n-6/n-3 ratio as close as possible to unity, along with a particular emphasis on consuming adequate amounts of essential fatty acids. The latest evidence shows cardioprotective effects of MUFA-rich diets, especially when MUFA are supplemented with essential fatty acids; namely, docosahexaenoic acid. MUFA has been newly suggested to be involved in regulating fat oxidation, energy metabolism, appetite sensations, weight maintenance, and cholesterol metabolism. These favorable effects might implicate MUFA as the preferable choice to substitute for other fatty acids, especially given the declaration of its safety for up to 20 % of total energy.

Fatty acid intake and metabolic syndrome among overweight and obese women

ABSTRACT: Objective: To examine relations between fatty acids intake and metabolic syndrome (MetS) status among overweight and obese women (n = 223). Methods: This was a cross-sectional study. The physical and laboratory tests included anthropometry, body composition evaluation and measurements of blood pressure, fasting blood glucose, insulinemia and lipid profiles. A three-day food diary was used to evaluate fatty acids consumption. Statistical analysis included χ2 test and odds ratio measurements. Results: The women had 35.2 (6.9) years old and 15.2% presented MetS. Women with MetS presented higher serum levels of very low-density lipoprotein cholesterol, triglycerides, glucose and insulin in addition to higher diastolic blood pressure in comparison to women without MetS. Overweight women with MetS consumed higher amounts of monounsaturated fatty acids - 24.3 g (24.7 - 36.4) versus overweight women without MetS - 23.9 g (23.8 - 26.8), polyunsaturated fatty acids - 16.7 g (14.6 - 21.1) versus overweight women without MetS - 13.6 g (13.8 - 15.8) and linoleic fatty acids - 15.9 g (6.5) versus overweight women without MetS - 13.1 g (5.1). Among obese women with MetS, higher intake of linoleic fatty acids was also noted - 17.6 g (6.1) versus obese women without MetS - 14.3 g (6.6) in addition to higher consumption of trans fatty acids - 4.7 g (4.8 - 6.3) versus obese women without MetS - 3.9 g (2.9 - 4.6). Increased quartiles of monounsaturated, polyunsaturated, linoleic and trans fatty acid intake were significantly associated with a greater occurrence of MetS. Conclusion: Lipid intake may be related to MetS, although other factors also need to be considered, such as lifestyle, genetics and metabolism.

Hepatocytes respond differently to major dietary trans fatty acid isomers, elaidic acid and trans-vaccenic acid

BACKGROUND

It has been discussed if the adverse health effect associated with the ingestion of trans fatty acids correlates with the food source, as the composition of the isomers varies in different foods. We have investigated the hepatocellular responses to the predominant trans fatty acid isomers in industrially produced partially hydrogenated vegetable oils (elaidic acid) and products of ruminant origin (trans-vaccenic acid).

RESULTS

The responses of HepG2-SF cells exposed to 100 μM fatty acids during 7 days were examined. Elaidic acid decreased the cellular proliferation rate while trans-vaccenic acid had no effect. Analysis of cellular triacylglycerol fractions showed, that both trans fatty acids were metabolized by HepG2-SF cells, although elaidic acid, to a higher degree than trans-vaccenic, accumulated in the triacylglycerol fraction. Proteome analysis revealed that the overlap of differentially regulated proteins only contained four proteins, suggesting that the two trans fatty acid isomers affect the cells in different ways. The data are available via ProteomeXchange with identifier PXD000760.

CONCLUSIONS

Our investigations revealed that the hepatocellular response to the two most abundant dietary positional C18:1 trans fatty acid isomers differ substantially. In addition, the results suggest that trans-vaccenic acid does not affect cholesterol metabolism adversely compared to elaidic acid.

European Code against Cancer 4th Edition: Diet and cancer

Lifestyle factors, including diet, have long been recognised as potentially important determinants of cancer risk. In addition to the significant role diet plays in affecting body fatness, a risk factor for several cancers, experimental studies have indicated that diet may influence the cancer process in several ways. Prospective studies have shown that dietary patterns characterised by higher intakes of fruits, vegetables, and whole-grain foods, and lower intakes of red and processed meats and salt, are related to reduced risks of death and cancer, and that a healthy diet can improve overall survival after diagnosis of breast and colorectal cancers. There is evidence that high intakes of fruit and vegetables may reduce the risk of cancers of the aerodigestive tract, and the evidence that dietary fibre protects against colorectal cancer is convincing. Red and processed meats increase the risk of colorectal cancer. Diets rich in high-calorie foods, such as fatty and sugary foods, may lead to increased calorie intake, thereby promoting obesity and leading to an increased risk of cancer. There is some evidence that sugary drinks are related to an increased risk of pancreatic cancer. Taking this evidence into account, the 4th edition of the European Code against Cancer recommends that people have a healthy diet to reduce their risk of cancer: they should eat plenty of whole grains, pulses, vegetables and fruits; limit high-calorie foods (foods high in sugar or fat); avoid sugary drinks and processed meat; and limit red meat and foods high in salt.

A randomized trial on the effects of 2010 Dietary Guidelines for Americans and Korean diet patterns on cardiovascular risk factors in overweight and obese adults

BACKGROUND

Dietary patterns that are considered healthy (eg, the Dietary Approaches to Stop Hypertension diet and Mediterranean diet) may be more successful in reducing typical cardiovascular disease risks compared to dietary patterns considered unhealthy (eg, energy-dense diets such as the typical American diet).

OBJECTIVE

This study assessed the effects of a Korean diet, the 2010 Dietary Guidelines for Americans (DGA), and a typical American diet on cardiometabolic risk factors, including lipid levels and blood pressure, in overweight, non-Asian individuals in the United States with elevated low-density lipoprotein cholesterol.

DESIGN/INTERVENTION

The study was a three-period crossover, controlled-feeding study from January 2012 to May 2012. Thirty-one subjects were randomly allocated to one of six possible sequential orders for consuming the three diets for 4 weeks, each separated by a 10-day break. Data analysis included 27 subjects on the Korean diet periods and 29 in the DGA and typical American diet periods. Subjects remained weight stable.

MAIN OUTCOME MEASURES

Lipid profile, blood pressure, insulin, glucose, and 24-hour urinary sodium were determined at baseline and at the end of each diet period.

STATISTICAL ANALYSES PERFORMED

The additive main effects multiplicative interactions model was used to test for a subject by diet interaction. Differences among diets were determined using a mixed-models procedure (PROC MIXED) with random intercept for each subject.

RESULTS

Total cholesterol and low-density lipoprotein cholesterol significantly decreased on Korean (P<0.0001 and P<0.01, respectively) and DGA (P<0.01 and P<0.05, respectively) diets, but not on the typical American diet. Although an unfavorable outcome, high-density lipoprotein cholesterol significantly decreased on all three diets (Korean: P<0.0001; DGA: P<0.0001; typical American: P<0.05). No diet had a significant effect on serum triglycerides, but a slight increase in triglycerides in the Korean and decrease in the DGA resulted in a significant difference between these two diets (P<0.01). All three diets caused modest decreases in systolic and diastolic blood pressure, which reached statistical significance for DGA only (P<0.05 and P<0.01, respectively). No diet had significant effect on fasting insulin, whereas fasting glucose decreased significantly on the Korean (P<0.01) and typical American (P<0.05) diets only. Urinary sodium output decreased significantly on DGA (P<0.0001).

CONCLUSIONS

After a 4-week feeding period, Korean and DGA diet patterns resulted in positive changes in cardiovascular disease risk factors.

Maternal saturated-fat-rich diet promotes leptin resistance in fetal liver lipid catabolism and programs lipid homeostasis impairments in the liver of rat offspring

We aimed to analyze if an overload of saturated fat in maternal diet induced lipid metabolic impairments in livers from rat fetuses that persist in the offspring and to identify potential mechanisms involving fetal leptin resistance. Female rats were fed either a diet enriched in 25% of saturated fat (SFD rats) or a regular diet (controls). Fetuses of 21days of gestation and offspring of 21 and 140days of age were obtained and plasma and liver were kept for further analysis. Livers from a group of control and SFD fetuses were cultured in the presence or absence of leptin. Leptin or vehicle was administered to control fetuses during the last days of gestation and, on day 21, fetal livers and plasma were obtained. Lipid levels were assessed by thin-layer chromatography and mRNA gene expression of CPT1, ACO and PPARα by RT-PCR. Liver lipid levels were increased and CPT1 and ACO were down-regulated in fetuses and offspring from SFD rats compared to controls. After the culture with leptin, control fetal livers showed increased ACO and CPT1 expression and decreased lipid levels, while fetal livers from SFD rats showed no changes. Fetal administration of leptin induced a decrease in ACO and no changes in CPT1 expression. In summary, our results suggest that a saturated fat overload in maternal diet induces fetal leptin resistance in liver lipid catabolism, which might be contributing to liver lipid alterations that are sustained in the offspring.

Activity of dietary fatty acids on FFA1 and FFA4 and characterisation of pinolenic acid as a dual FFA1/FFA4 agonist with potential effect against metabolic diseases

Various foods are associated with effects against metabolic diseases such as insulin resistance and type 2 diabetes; however, their mechanisms of action are mostly unclear. Fatty acids may contribute by acting as precursors of signalling molecules or by direct activity on receptors. The medium- and long-chain NEFA receptor FFA1 (free fatty acid receptor 1, previously known as GPR40) has been linked to enhancement of glucose-stimulated insulin secretion, whereas FFA4 (free fatty acid receptor 4, previously known as GPR120) has been associated with insulin-sensitising and anti-inflammatory effects, and both receptors are reported to protect pancreatic islets and promote secretion of appetite and glucose-regulating hormones. Hypothesising that FFA1 and FFA4 mediate therapeutic effects of dietary components, we screened a broad selection of NEFA on FFA1 and FFA4 and characterised active compounds in concentration-response curves. Of the screened compounds, pinolenic acid, a constituent of pine nut oil, was identified as a relatively potent and efficacious dual FFA1/FFA4 agonist, and its suitability for further studies was confirmed by additional in vitro characterisation. Pine nut oil and free and esterified pure pinolenic acid were tested in an acute glucose tolerance test in mice. Pine nut oil showed a moderately but significantly improved glucose tolerance compared with maize oil. Pure pinolenic acid or ethyl ester gave robust and highly significant improvements of glucose tolerance. In conclusion, the present results indicate that pinolenic acid is a comparatively potent and efficacious dual FFA1/FFA4 agonist that exerts antidiabetic effects in an acute mouse model. The compound thus deserves attention as a potential active dietary ingredient to prevent or counteract metabolic diseases.

Genetic loci associated with circulating phospholipid trans fatty acids: a meta-analysis of genome-wide association studies from the CHARGE Consortium

BACKGROUND

Circulating trans fatty acids (TFAs), which cannot be synthesized by humans, are linked to adverse health outcomes. Although TFAs are obtained from diet, little is known about subsequent influences (e.g., relating to incorporation, metabolism, or intercompetition with other fatty acids) that could alter circulating concentrations and possibly modulate or mediate impacts on health.

OBJECTIVE

The objective was to elucidate novel biologic pathways that may influence circulating TFAs by evaluating associations between common genetic variation and TFA biomarkers.

DESIGN

We performed meta-analyses using 7 cohorts of European-ancestry participants (n = 8013) having measured genome-wide variation in single-nucleotide polymorphisms (SNPs) and circulating TFA biomarkers (erythrocyte or plasma phospholipids), including trans-16:1n-7, total trans-18:1, trans/cis-18:2, cis/trans-18:2, and trans/trans-18:2. We further evaluated SNPs with genome-wide significant associations among African Americans (n = 1082), Chinese Americans (n = 669), and Hispanic Americans (n = 657) from 2 of these cohorts.

RESULTS

Among European-ancestry participants, 31 SNPs in or near the fatty acid desaturase (FADS) 1 and 2 cluster were associated with cis/trans-18:2; a top hit was rs174548 (β = 0.0035, P = 4.90 × 10(-15)), an SNP previously associated with circulating n-3 and n-6 polyunsaturated fatty acid concentrations. No significant association was identified for other TFAs. rs174548 in FADS1/2 was also associated with cis/trans-18:2 in Hispanic Americans (β = 0.0053, P = 1.05 × 10(-6)) and Chinese Americans (β = 0.0028, P = 0.002) but not African Americans (β = 0.0009, P = 0.34); however, in African Americans, fine mapping identified a top hit in FADS2 associated with cis/trans-18:2 (rs174579: β = 0.0118, P = 4.05 × 10(-5)). The association between rs174548 and cis/trans-18:2 remained significant after further adjustment for individual circulating n-3 and n-6 fatty acids, except arachidonic acid. After adjustment for arachidonic acid concentrations, the association between rs174548 and cis/trans-18:2 was nearly eliminated in European-ancestry participants (β-coefficient reduced by 86%), with similar reductions in Hispanic Americans and Chinese Americans.

CONCLUSIONS

Our findings provide novel evidence for genetic regulation of cis/trans-18:2 by the FADS1/2 cluster and suggest that this regulation may be influenced/mediated by concentrations of arachidonic acid, an n-6 polyunsaturated fat.

Nutrients other than carbohydrates: their effects on glucose homeostasis in humans

Besides carbohydrates, other nutrients, such as dietary protein and amino acids; the supply of fat, vitamin D, and vitamin K; and sodium intake seem to affect glucose homeostasis. Although their effect is less pronounced than that of the amount and composition of carbohydrates, it seems reasonable to consider how nutrient intake habits may be modified to support an improved glucose homeostasis. For instance, taking into account the effect of some nutrients to lower blood glucose concentration on a day-by-day basis might support improvement of glucose homeostasis in the long run. On the other hand, lowering sodium intake too much, as recommended to avoid the development of hypertension, particularly in sodium-sensitive people, might lead to insulin resistance and thereby might risk increasing fasting as well as postprandial blood glucose concentrations. This review summarizes the state of our knowledge of how several nutrients other than carbohydrates, such as protein, fatty acids, vitamin D, vitamin K, magnesium, zinc, chromium, and sodium, affect blood glucose concentrations. Sufficient evidence exists to show that, in prospective studies based on randomized controlled trials, these selected nutrients affect blood glucose regulation. The review describes potential mechanisms leading to the observed effect. As much as is possible from the available data, the extent of the effect, is considered.

F2-isoprostanes are correlated with trans fatty acids in the plasma of pregnant women

We hypothesized that the mild physiological oxidative stress present during pregnancy could increase both, plasma F2-isoprostanes (F2-isoPs) by lipid oxidation and trans fatty acids (TFA) through cis-trans isomerization respectively. Plasma samples collected at 12-18 weeks (MIROS cohort; n=65) and 38-41 weeks of pregnancy (CHUL cohort; n=21) were subjected to alkaline hydrolysis followed by liquid-liquid extraction in order to extract total F2-isoPs for quantification by HPLC-MS/MS. Several positive correlations were found between F2-isoPs and TFA, measured by GC-FID in plasma phospholipids, such as 6t-18:1, 9t-18:1 and 9t,12c-18:2 (r>0.306; p<0.045). Despite its low level, the 9t,12c-18:2 trans isomer, known to be associated to cardiovascular diseases, showed the most significant correlations with F2-isoPs. No correlation was observed between F2-isoPs and 9t-16:1 or 11t-18:1. In summary, this study suggests either a concomitant phenomenon or a competition between lipid peroxidation and cis-trans isomerisation of the cis precursor fatty acid in vivo during pregnancy.

Effects of elaidic acid, a predominant industrial trans fatty acid, on bacterial growth and cell surface hydrophobicity of lactobacilli

The consumption of trans fatty acids (TFAs) increases the risk of cardiovascular diseases and coronary heart disease in human, and there are no effective ways to remove TFAs after consumption. The aim of this study was to investigate the effects of elaidic acid on bacterial growth, cell surface hydrophobicity of lactobacilli, and metabolism of elaidic acid by lactobacilli. Lactobacilli were inoculated in MRS broth containing 0, 100, 200, and 500 mg/L of elaidic acid. Viable cell counts of lactobacilli were enumerated, concentrations of elaidic acid were determined, and cell surface hydrophobicity of lactobacilli was measured. The results showed that the growth of lactobacilli was significantly inhibited by 500 mg/L of elaidic acid, however, a cell count of 8.50 log10 CFU/mL was still reached for tested lactobacilli after 24-h incubation. In particular, a reduction of elaidic acid was found for tested lactobacilli after 24-h incubation as compared to its initial concentration of 200 mg/L. However, cell surface hydrophobicity showed no correlations with the metabolism of elaidic acid by lactobacilli. Moreover, elaidic acid was able to influence cell surface hydrophobicity, and the decrease in hydrophobicity was more obvious in Lactobacillus paracasei and Lactobacillus casei compared with that in other tested lactobacilli. This study suggests that elaidic acid could change physiochemical surface properties of lactobacilli and the lactobacilli have the potential to reduce TFAs.

Elaidate, an 18-carbon trans-monoenoic fatty acid, inhibits β-oxidation in human peripheral blood macrophages

Consumption of trans-unsaturated fatty acids promotes atherosclerosis, but whether degradation of fats in macrophages is altered by trans-unsaturated fatty acids is unknown. We compared the metabolism of oleate (C18:1Δ9-10 cis; (Z)-octadec-9-enoate), elaidate (C18:Δ9-10 trans; (E)-octadec-9-enoate), and stearate (C18:0, octadecanoate) in adherent peripheral human macrophages. Metabolism was followed by measurement of acylcarnitines in cell supernatants by MS/MS, determination of cellular fatty acid content by GC/MS, and assessment of β-oxidation rates using radiolabeled fatty acids. Cells incubated for 44 h in 100 µM elaidate accumulated more unsaturated fatty acids, including both longer- and shorter-chain, and had reduced C18:0 relative to those incubated with oleate or stearate. Both C12:1 and C18:1 acylcarnitines accumulated in supernatants of macrophages exposed to trans fats. These results suggested β-oxidation inhibition one reaction proximal to the trans bond. Comparison of [1-(14)C]oleate to [1-(14)C]elaidate catabolism showed that elaidate completed the first round of fatty acid β-oxidation at rates comparable to oleate. Yet, in competitive β-oxidation assays with [9,10-(3)H]oleate, tritium release rate decreased when unlabeled oleate was replaced by the same quantity of elaidate. These data show specific inhibition of monoenoic fat catabolism by elaidate that is not shared by other atherogenic fats.

Dietary fat quality impacts genome-wide DNA methylation patterns in a cross-sectional study of Greek preadolescents

The type and the amount of dietary fat have a significant influence on the metabolic pathways involved in the development of obesity, metabolic syndrome, diabetes type 2 and cardiovascular diseases. However, it is unknown to what extent this modulation is achieved through DNA methylation. We assessed the effects of cholesterol intake, the proportion of energy intake derived from fat, the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA), the ratio of monounsaturated fatty acids (MUFA) to SFA, and the ratio of MUFA+PUFA to SFA on genome-wide DNA methylation patterns in normal-weight and obese children. We determined the genome-wide methylation profile in the blood of 69 Greek preadolescents (∼10 years old) as well as their dietary intake for two consecutive weekdays and one weekend day. The methylation levels of one CpG island shore and four sites were significantly correlated with total fat intake. The methylation levels of 2 islands, 11 island shores and 16 sites were significantly correlated with PUFA/SFA; of 9 islands, 26 island shores and 158 sites with MUFA/SFA; and of 10 islands, 40 island shores and 130 sites with (MUFA+PUFA)/SFA. We found significant gene enrichment in 34 pathways for PUFA/SFA, including the leptin pathway, and a significant enrichment in 5 pathways for (MUFA+PUFA)/SFA. Our results suggest that specific changes in DNA methylation may have an important role in the mechanisms involved in the physiological responses to different types of dietary fat.

Trans fatty acid content in Malaysian supermarket foods: a field-to-laboratory approach in assessing food risk

The extent of industrial trans fatty acids (TFA) in the food supply is unknown in Malaysia, whilst TFA disclosure on food labels is not mandatory by Malaysian food standards. Supermarket foods such as dairy products, fats and oils, meat products, snack foods, soups, and confectionery are commonly cited to be major contributors of TFA in the diet. A consumer survey (n = 622) was used to develop a food listing of these 'high risk' foods. TFA content of high-risk foods were analysed by gas chromatography. Food samples (n = 158) were analysed and their total TFA content were compared with Malaysian Food Standards. A wide variation in TFA content within food categories was indicated. Of the foods containing TFA, many food labels did not cite TFA content or the use of partially hydrogenated vegetable oils (PHVO) as an ingredient. Hypothesised estimates of TFA intake from these supermarket foods in a sample day's menu providing 2000 kcal projected a minimum intake of 0.5 g and a maximum intake of 5.2 g TFA. This study found there was no voluntary disclosure of TFA content on food labels or identifying PHVO as an ingredient. It appears that health education targeting consumers to minimise TFA consumption is required supported by mandatory PHVO disclosure on the food label.

Modeling progressive non-alcoholic fatty liver disease in the laboratory mouse

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world and its prevalence is rising. In the absence of disease progression, fatty liver poses minimal risk of detrimental health outcomes. However, advancement to non-alcoholic steatohepatitis (NASH) confers a markedly increased likelihood of developing severe liver pathologies, including fibrosis, cirrhosis, organ failure, and cancer. Although a substantial percentage of NAFLD patients develop NASH, the genetic and molecular mechanisms driving this progression are poorly understood, making it difficult to predict which patients will ultimately develop advanced liver disease. Deficiencies in mechanistic understanding preclude the identification of beneficial prognostic indicators and the development of effective therapies. Mouse models of progressive NAFLD serve as a complementary approach to the direct analysis of human patients. By providing an easily manipulated experimental system that can be rigorously controlled, they facilitate an improved understanding of disease development and progression. In this review, we discuss genetically- and chemically-induced models of NAFLD that progress to NASH, fibrosis, and liver cancer in the context of the major signaling pathways whose disruption has been implicated as a driving force for their development. Additionally, an overview of nutritional models of progressive NAFLD is provided.

Influence of lifestyle on the course of type 1 diabetes mellitus

Type 1 diabetes (T1DM) is an autoimmune disease that requires insulin treatment from the time of diagnosis. Its clinical course depends on both genetic and environmental factors, and the lifestyle of a patient modulates their interaction. The evidence about the influence of lifestyle on the course of T1DM is increasing. In this paper, we present evidence on the relationship between lifestyle parameters and diabetes-related outcomes. We discuss the most commonly addressed factors associated with lifestyle, such as physical activity, nutrition and smoking, and those with sparse evidence in T1DM, such as socioeconomic status, sleep duration, psychological stress and illicit drugs intake.

Trans fatty acids exacerbate dextran sodium sulphate-induced colitis by promoting the up-regulation of macrophage-derived proinflammatory cytokines involved in T helper 17 cell polarization

Numerous reports have shown that a diet containing large amounts of trans fatty acids (TFAs) is a major risk factor for metabolic disorders. Although recent studies have shown that TFAs promote intestinal inflammation, the underlying mechanisms are unknown. In this study, we examined the effects of dietary fat containing TFAs on dextran sodium sulphate (DSS)-induced colitis. C57 BL/6 mice were fed a diet containing 1·3% TFAs (mainly C16:1, C18:1, C18:2, C20:1, C20:2 and C22:1), and then colitis was induced with 1·5% DSS. Colonic damage was assessed, and the mRNA levels of proinflammatory cytokines and major regulators of T cell differentiation were measured. The TFA diet reduced survival and exacerbated histological damage in mice administered DSS compared with those fed a TFA-free diet. The TFA diet significantly elevated interleukin (IL)-6, IL-12p40, IL-23p19 and retinoic acid-related orphan receptor (ROR)γt mRNA levels in the colons of DSS-treated animals. Moreover, IL-17A mRNA levels were elevated significantly by the TFA diet, with or without DSS treatment. We also examined the expression of proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and peritoneal macrophages. These cells were exposed to TFAs (linoelaidic acid or elaidic acid) with or without LPS and the mRNA levels of various cytokines were measured. IL-23p19 mRNA levels were increased significantly by TFAs in the absence of LPS. Cytokine expression was also higher in LPS-stimulated cells exposed to TFAs than in unexposed LPS-stimulated cells. Collectively, our results suggest that TFAs exacerbate colonic inflammation by promoting Th17 polarization and by up-regulating the expression of proinflammatory cytokines in the inflamed colonic mucosa.

Trans fatty acids in diets act as a precipitating factor for gut inflammation?

Fatty acids in our daily diet are broadly classified into cis and trans fatty acids (TFAs). TFAs are formed during the manufacturing process of hydrogenated vegetable oils such as margarine. Modern diets such as deep-fried products, frozen foods, and packaged snacks commonly include large quantities of margarine containing TFAs. Although an increased report in the effects of the diet containing TFAs on a risk factor of metabolic syndrome, diabetes mellitus, and coronary heart disease has been observed in the recent years, influence on intestinal inflammation remains unknown. This review describes pro-inflammatory effects of TFAs in our diary diet on various systemic disorders and also discusses a possible role of TFAs on gut inflammation.

Adipose tissue trans-fatty acids and changes in body weight and waist circumference

Previous studies have suggested that the intake of trans-fatty acids (TFA) plays a role in the development of obesity. The proportions of adipose tissue fatty acids not synthesised endogenously in humans, such as TFA, usually correlate well with the dietary intake. Hence, the use of these biomarkers may provide a more accurate measure of habitual TFA intake than that obtained with dietary questionnaires. The objective of the present study was to investigate the associations between the proportions of specific TFA in adipose tissue and subsequent changes in weight and waist circumference (WC). The relative content of fatty acids in adipose tissue biopsies from a random sample of 996 men and women aged 50-64 years drawn from a Danish cohort study was determined by GC. Baseline data on weight, WC and potential confounders were available together with information on weight and WC 5 years after enrolment. The exposure measures were total trans-octadecenoic acids (18:1t), 18:1 Δ6-10t, vaccenic acid (18:1 Δ11t) and rumenic acid (18:2 Δ9c, 11t). Data were analysed using multiple regression with cubic spline modelling. The median proportion of total adipose tissue 18:1t was 1.52% (90% central range 0.98, 2.19) in men and 1.47% (1.01, 2.19) in women. No significant associations were observed between the proportions of total 18:1t, 18:1 Δ6-10t, vaccenic acid or rumenic acid and changes in weight or WC. The present study suggests that the proportions of specific TFA in adipose tissue are not associated with subsequent changes in weight or WC within the exposure range observed in this population.

Dietary and lifestyle characteristics associated with normal-weight obesity: the National FINRISK 2007 Study

The aim of the present study was to compare the lifestyle (leisure-time physical activity, smoking habits and alcohol consumption) and dietary (energy-yielding nutrients, dietary fibre and foods) factors of Finns with a new syndrome called normal-weight obesity (NWO) with those of lean and overweight Finns. The representative population-based study included 4786 participants (25-74 years) from the National FINRISK 2007 Study with a health examination and questionnaires. Food intake was assessed using a validated FFQ. NWO was defined to include those with a normal BMI (<25 kg/m²) but excessive body fat (for men ≥20 % and for women ≥30 %) according to WHO definitions. The proportion of participants with a normal BMI was 28 % in men and 42 % in women. Of these, 34 % of the men and 45 % of the women had the NWO syndrome (among all the participants, 10 and 19 %, respectively). The waist circumference of the NWO participants was between that of the lean and overweight participants. Some potential risk factors, such as physical inactivity, (ex)-smoking and alcohol consumption, were related to NWO. In general, the intakes of energy-yielding nutrients were not associated with NWO. Instead, some healthy dietary factors (e.g. low intakes of meat and soft drinks) as well as unhealthy factors (e.g. low intakes of root vegetables, cereals and fish and high intake of confectionery) were related to NWO. The findings might explain why the NWO participants were of normal weight, but had an excessive body fat percentage. In conclusion, the proportion of normal-weight participants with an excessive body fat percentage was surprisingly high. The identification of NWO people may be of importance because although they appear lean, they have some unhealthy lifestyle and dietary habits related to obesity and overall health.

Metabolic disturbances connecting obesity and depression

Obesity markedly increases the odds of developing depression. Depressed mood not only impairs motivation, quality of life and overall functioning but also increases the risks of obesity complications. Abdominal obesity is a better predictor of depression and anxiety risk than overall adipose mass. A growing amount of research suggests that metabolic abnormalities stemming from central obesity that lead to metabolic disease may also be responsible for the increased incidence of depression in obesity. As reviewed here, a higher mass of dysfunctional adipose tissue is associated with several metabolic disturbances that are either directly or indirectly implicated in the control of emotions and mood. To better comprehend the development of depression in obesity, this review pulls together select findings addressing the link between adiposity, diet and negative emotional states and discusses the evidence that alterations in glucocorticoids, adipose-derived hormones, insulin and inflammatory signaling that are characteristic of central obesity may be involved.

Dietary trans fats enhance doxorubicin-induced cardiotoxicity in mice

This study investigated the combined effects of trans fat diet (TFD) and doxorubicin upon cardiac oxidative, inflammatory, and coagulatory stress. TFD increased trans fatty acid deposit in heart (P < 0.05), and decreased protein C and antithrombin-III activities in circulation (P < 0.05). TFD plus doxorubicin treatment elevated activities of plasminogen activator inhibitor-1, lactate dehydrogenase, and creatine phosphokinase (P < 0.05). This combination also raised xanthine oxidase activity, and enhanced cardiac levels of reactive oxygen species, interleukin (IL)-6, IL-10, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1 than TFD or doxorubicin treatment alone (P < 0.05). TFD alone increased cardiac nuclear factor kappa B (NF-κB) activity (P < 0.05), but failed to affect expression of NF-κB and mitogen-activated protein kinase (MAPK) (P > 0.05). Doxorubicin treatment alone augmented cardiac activity, mRNA expression, and protein production of NF-κB and MAPK (P < 0.05). TFD plus doxorubicin treatment further upregulated cardiac expression of NF-κB p65, p-p38, and p-ERK1/2 (P < 0.05). These findings suggest that TFD exacerbates doxorubicin-induced cardiotoxicity.

High-fat feeding-induced hyperinsulinemia increases cardiac glucose uptake and mitochondrial function despite peripheral insulin resistance

In obesity, reduced cardiac glucose uptake and mitochondrial abnormalities are putative causes of cardiac dysfunction. However, high-fat diet (HFD) does not consistently induce cardiac insulin resistance and mitochondrial damage, and recent studies suggest HFD may be cardioprotective. To determine cardiac responses to HFD, we investigated cardiac function, glucose uptake, and mitochondrial respiration in young (3-month-old) and middle-aged (MA) (12-month-old) male Ldlr(-/-) mice fed chow or 3 months HFD to induce obesity, systemic insulin resistance, and hyperinsulinemia. In MA Ldlr(-/-) mice, HFD induced accelerated atherosclerosis and nonalcoholic steatohepatitis, common complications of human obesity. Surprisingly, HFD-fed mice demonstrated increased cardiac glucose uptake, which was most prominent in MA mice, in the absence of cardiac contractile dysfunction or hypertrophy. Moreover, hearts of HFD-fed mice had enhanced mitochondrial oxidation of palmitoyl carnitine, glutamate, and succinate and greater basal insulin signaling compared with those of chow-fed mice, suggesting cardiac insulin sensitivity was maintained, despite systemic insulin resistance. Streptozotocin-induced ablation of insulin production markedly reduced cardiac glucose uptake and mitochondrial dysfunction in HFD-fed, but not in chow-fed, mice. Insulin injection reversed these effects, suggesting that insulin may protect cardiac mitochondria during HFD. These results have implications for cardiac metabolism and preservation of mitochondrial function in obesity.

Differential regulation of ABCA1 and macrophage cholesterol efflux by elaidic and oleic acids

Trans fatty acid consumption is associated with an increased risk of coronary heart disease. This increased risk has been attributed to decreased levels of HDL cholesterol and increased levels of LDL cholesterol. However, the mechanism by which trans fatty acid modulates cholesterol transit remains poorly defined. ATP-binding cassette transporter A1 (ABCA1)-mediated macrophage cholesterol efflux is the rate-limiting step initiating apolipoprotein A-I lipidation. In this study, elaidic acid, the most abundant trans fatty acid in partially hydrogenated vegetable oil, was shown to stabilize macrophage ABCA1 protein levels in comparison to that of its cis fatty acid isomer, oleic acid. The mechanism responsible for the disparate effects of oleic and elaidic acid on ABCA1 levels was through accelerated ABCA1 protein degradation in cells treated with oleic acid. In contrast, no apparent differences were observed in ABCA1 mRNA levels, and only minor changes were observed in Liver X receptor/Retinoic X receptor promoter activity in cells treated with elaidic and oleic acid. Efflux of both tracers and cholesterol mass revealed that elaidic acid slightly increased ABCA1-mediated cholesterol efflux, while oleic acid led to decreased ABCA1-mediated efflux. In conclusion, these studies show that cis and trans structural differences in 18 carbon n-9 monoenoic fatty acids variably impact cholesterol efflux through disparate effects on ABCA1 protein degradation.