History of recommendations to the public about dietary fat

The Effect of Maternal Exposure to a Diet High in Fats and Cholesterol on the Placental Function and Phenotype of the Offspring in a Rabbit Model: A Summary Review of About 15 Years of Research

The rates of obesity and being overweight are increasing all around the world, especially among women of childbearing age, in part due to overconsumption of lipids. The aim of this summary review was to present the cellular and molecular effects of a hyperlipidic high-cholesterol (H) diet on the maternal and offspring phenotype at the early embryonic, neonatal, weaning and adult stages while considering the effects of sex and to identify the window(s) of vulnerability linked to this exposure in a rabbit model. Before breeding, the H diet induced dyslipidemia and aortic atherosclerosis lesions and increased the number of atretic follicles. In the offspring, the H diet disrupted the embryonic phenotype and induced fetal hypotrophy associated with sex-specific disturbances of the feto-placental unit. In adulthood, the offspring of the H dams were heavier and hyperphagic and had increased blood pressure associated with disturbed gonadal development in both sexes. Vulnerability windows were explored via embryo transfers. The maternal gestational diet was shown to play a key role in the feto-placental phenotype, and preconception programming was unquestionably also observed. These two periods could represent windows of intervention in the context of obesity or being overweight to limit fetal and placental consequences.

Total added sugar consumption is not significantly associated with risk for prediabetes among U.S. adults: National Health and Nutrition Examination Survey, 2013-2018

Prediabetes affects 38% of U.S. adults and is primarily linked to added sugars consumed from sugar-sweetened beverages. It is unclear if total dietary intake of added sugar also increases the risk for prediabetes. This study examined if total (g/day) and percent intakes of <10%, 10-15%, or >15% added sugar increase the odds for prediabetes in U.S. adults. A cross-sectional, secondary analysis using 2013-2018 NHANES data was conducted. This study included data from U.S. adults ≥ 20 years with normoglycemia (N = 2,154) and prediabetes (N = 3,152) with 1-2 days of dietary recall information. Prediabetes was defined as a hemoglobin A1c of 5.7%-6.4% or a fasting plasma glucose of 100-125 mg/dL. Survey-weighted logistic regression was used to estimate odds ratios of prediabetes based on usual intakes of added sugar (total and percent intakes) using the National Cancer Institute Method. Differences in prediabetes risk and total and percent intakes of added sugar were compared by race/ethnicity. The sample's total energy intake from added sugar was 13.9%. Total (unadjusted: OR: 1.01, 95% CI: .99-1.00, p = .26; adjusted: OR: 1.00, 95% CI: .99-1.00, p = .91) and percent intakes of added sugar (unadjusted [<10%: (ref); 10-15%: OR: .93, 95% CI: .77-1.12, p = .44; >15%: OR: 1.03, 95% CI: .82-1.28, p = .82] and adjusted [<10%: (ref); 10-15%: OR: .82, 95% CI: .65-1.04, p = .09; >15%: OR: .96, 95% CI: .74-1.24, p = .73]) were not significantly associated with an increased odds of prediabetes. Prediabetes risk did not differ by race/ethnicity for total (unadjusted model [p = .65]; adjusted model [p = .51]) or percent (unadjusted model [p = .21]; adjusted model [p = .11]) added sugar intakes. In adults ≥20 years with normoglycemia and prediabetes, total added sugar consumption did not significantly increase one's risk for prediabetes and risk estimates did not differ by race/ethnicity. Experimental studies should expand upon this work to confirm these findings.

Fatty Acid Indices and the Nutritional Properties of Karakul Sheep Meat

This study aimed to evaluate the fatty acid profile and health lipid indices of sheep meat (from 52 Karakul sheep from NE Romania). The effect of age at slaughter and the influence of muscle region were studied for nutritional parameters, especially the fatty acids from lipid fractions. Based on the fatty acid profiles and lipid contents, the sanogenic indices were determined for two sheep muscle groups. Thus, two different muscle regions from lamb and adult sheep were analysed from both genders, the Longissimus dorsi and Triceps brachii, to argue the advantages of each category and the rationalization, in terms of meat consumption, regarding their impact on human health. Sheep meat has many components with beneficial effects on human health. Apart from the fact that it is an important source of nutrients due to its high content of proteins, lipids, and minerals, it is also a product that can provide fundamental bioactive compounds for maintaining metabolic functions. The qualitative indices assessment revealed that lambs have meat with high PUFA content on Longissimus dorsi muscles (approx. 25% of total fatty acids), 0.68 for PUFA/SFA, with highest values for n-3 (approx. 8%) and n-6 (approx. 14%). Appropriate values can also be observed in Triceps brachii muscles from adult sheep. The sanogenic indices also presented good values for Longissimus dorsi from lambs and Triceps brachii from adult sheep (polyunsaturation index = 7.2-10.2; atherogenic index = 0.56-0.67; thrombogenic index = 0.78-0.96; hypocholesterolemic/hypercholesterolemic index = 2.4-2.7 (for Longissimus dorsi)).

A 130-year global inventory of methane emissions from livestock: Trends, patterns, and drivers

Livestock contributes approximately one-third of global anthropogenic methane (CH₄ ) emissions. Quantifying the spatial and temporal variations of these emissions is crucial for climate change mitigation. Although country-level information is reported regularly through national inventories and global databases, spatially explicit quantification of century-long dynamics of CH₄ emissions from livestock has been poorly investigated. Using the Tier 2 method adopted from the 2019 Refinement to 2006 IPCC guidelines, we estimated CH₄ emissions from global livestock at a spatial resolution of 0.083° (~9 km at the equator) during the period 1890-2019. We find that global CH₄ emissions from livestock increased from 31.8 [26.5-37.1] (mean [minimum-maximum of 95% confidence interval) Tg CH₄ yr^-1 in 1890 to 131.7 [109.6-153.7] Tg CH₄ yr^-1 in 2019, a fourfold increase in the past 130 years. The growth in global CH₄ emissions mostly occurred after 1950 and was mainly attributed to the cattle sector. Our estimate shows faster growth in livestock CH₄ emissions as compared to the previous Tier 1 estimates and is ~20% higher than the estimate from FAOSTAT for the year 2019. Regionally, South Asia, Brazil, North Africa, China, the United States, Western Europe, and Equatorial Africa shared the majority of the global emissions in the 2010s. South Asia, tropical Africa, and Brazil have dominated the growth in global CH₄ emissions from livestock in the recent three decades. Changes in livestock CH₄ emissions were primarily associated with changes in population and national income and were also affected by the policy, diet shifts, livestock productivity improvement, and international trade. The new geospatial information on the magnitude and trends of livestock CH₄ emissions identifies emission hotspots and spatial-temporal patterns, which will help to guide meaningful CH₄ mitigation practices in the livestock sector at both local and global scales.

sEH-derived metabolites of linoleic acid drive pathologic inflammation while impairing key innate immune cell function in burn injury

Oxylipins alter immune cell function and potentially drive pathophysiology in burn and sepsis patients. Past and recent data reveal a correlation between increased systemic EpOME levels and reduced survival in human burn trauma and sepsis. This work extends these studies and provides evidence that the downstream sEH-derived metabolites, DiHOMEs, are driving worsening outcomes by altering the immune response. Inhibiting DiHOME metabolite formation with the sEH inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), restored immune function by increasing immune cell survival and function. These data support the hypothesis that sEH-derived linoleic acid diols are responsible for increased mortality in burn and sepsis patients and also provide a rationale for testing the therapeutic blockage of DiHOME generation in burn and sepsis patients to improve their outcomes.

Fatty acid composition in the Western diet has shifted from saturated to polyunsaturated fatty acids (PUFAs), and specifically to linoleic acid (LA, 18:2), which has gradually increased in the diet over the past 50 y to become the most abundant dietary fatty acid in human adipose tissue. PUFA-derived oxylipins regulate a variety of biological functions. The cytochrome P450 (CYP450)–formed epoxy fatty acid metabolites of LA (EpOMEs) are hydrolyzed by the soluble epoxide hydrolase enzyme (sEH) to dihydroxyoctadecenoic acids (DiHOMEs). DiHOMEs are considered cardioprotective at low concentrations but at higher levels have been implicated as vascular permeability and cytotoxic agents and are associated with acute respiratory distress syndrome in severe COVID-19 patients. High EpOME levels have also correlated with sepsis-related fatalities; however, those studies failed to monitor DiHOME levels. Considering the overlap of burn pathophysiology with these pathologies, the role of DiHOMEs in the immune response to burn injury was investigated. 12,13-DiHOME was found to facilitate the maturation and activation of stimulated neutrophils, while impeding monocyte and macrophage functionality and cytokine generation. In addition, DiHOME serum concentrations were significantly elevated in burn-injured mice and these increases were ablated by administration of 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), a sEH inhibitor. TPPU also reduced necrosis of innate and adaptive immune cells in burned mice, in a dose-dependent manner. The findings suggest DiHOMEs are a key driver of immune cell dysfunction in severe burn injury through hyperinflammatory neutrophilic and impaired monocytic actions, and inhibition of sEH might be a promising therapeutic strategy to mitigate deleterious outcomes in burn patients.

Diversity in citations to a single study: A citation context network analysis of how evidence from a prospective cohort study was cited

Between its origin in the 1950s and its endorsement by a consensus conference in 1984, the diet–heart hypothesis was the subject of intense controversy. Paul et al. (1963) is a highly cited prospective cohort study that reported findings inconvenient for this hypothesis, reporting no association between diet and heart disease; however, many other findings were also reported. By citation context and network analysis of 343 citing papers, I show how Paul et al. was cited in the 20 years after its publication. Generally, different findings were cited by different communities focusing on different risk factors; these communities were established by either research foci title terms or via cluster membership as established via modularity maximization. The most frequently cited findings were the significant associations between heart disease and serum cholesterol (n = 85), blood pressure (n = 57), and coffee consumption (n = 54). The lack of association between diet and heart disease was cited in just 41 papers. Yet, no single empirical finding was referred to in more than 25% of the citing papers. This raises questions about the value of inferring impact from citation counts alone and raises problems for studies using such counts to measure citation bias.

Low-Dose Coconut Oil Supplementation Induces Hypothalamic Inflammation, Behavioral Dysfunction, and Metabolic Damage in Healthy Mice

SCOPE

Coconut oil (CO) diets remain controversial due to the possible association with metabolic disorder and obesity. This study investigates the metabolic effects of a low amount of CO supplementation.

METHODS AND RESULTS

Swiss male mice are assigned to be supplemented orally during 8 weeks with 300 µL of water for the control group (CV), 100 or 300 µL of CO (CO100 and CO300) and 100 or 300 µL of soybean oil (SO; SO100 and SO300). CO led to anxious behavior, increase in body weight gain, and adiposity. In the hypothalamus, CO and SO increase cytokines expression and pJNK, pNFKB, and TLR4 levels. Nevertheless, the adipose tissue presented increases macrophage infiltration, TNF-α and IL-6 after CO and SO consumption. IL-1B and CCL2 expression, pJNK and pNFKB levels increase only in CO300. In the hepatic tissue, CO increases TNF-α and chemokines expression. Neuronal cell line (mHypoA-2/29) exposed to serum from CO and SO mice shows increased NFKB migration to the nucleus, TNF-α, and NFKBia expression, but are prevented by inhibitor of TLR4 (TAK-242).

CONCLUSIONS

These results show that a low-dose CO changes the behavioral pattern, induces inflammatory pathway activation, TLR4 expression in healthy mice, and stimulates the pro-inflammatory response through a TLR4-mediated mechanism.

A Villin-Driven Fxr Transgene Modulates Enterohepatic Bile Acid Homeostasis and Response to an n-6-Enriched High-Fat Diet

A diet high in n-6 polyunsaturated fatty acids (PUFAs) may contribute to inflammation and tissue damage associated with obesity and pathologies of the colon and liver. One contributing factor may be dysregulation by n-6 fatty acids of enterohepatic bile acid (BA) metabolism. The farnesoid X receptor (FXR) is a nuclear receptor that regulates BA homeostasis in the liver and intestine. This study aims to compare the effects on FXR regulation and BA metabolism of a palm oil-based diet providing 28% energy (28%E) from fat and low n-6 linoleic acid (LA, 2.5%E) (CNTL) with those of a soybean oil-based diet providing 50%E from fat and high (28%E) in LA (n-6HFD). Wild-type (WT) littermates and a transgenic mouse line overexpressing the Fxrα1 isoform under the control of the intestine-specific Villin promoter (Fxrα1^TG) were fed the CNTL or n-6HFD starting at weaning through 16 weeks of age. Compared to the CNTL diet, the n-6HFD supports higher weight gain in both WT and Fxrα^TG littermates; increases the expression of Fxrα1/2, and peroxisome proliferator-activated receptor-γ1 (Pparγ1) in the small intestine, Fxrα1/2 in the colon, and cytochrome P4507A1 (Cyp7a1) and small heterodimer protein (Shp) in the liver; and augments the levels of total BA in the liver, and primary chenodeoxycholic (CDCA), cholic (CA), and β-muricholic (βMCA) acid in the cecum. Intestinal overexpression of the Fxra1^TG augments expression of Shp and ileal bile acid-binding protein (Ibabp) in the small intestine and Ibabp in the proximal colon. Conversely, it antagonizes n-6HFD-dependent accumulation of intestinal and hepatic CDCA and CA; hepatic levels of Cyp7a1; and expression of Pparγ in the small intestine. We conclude that intestinal Fxrα1 overexpression represses hepatic de novo BA synthesis and protects against n-6HFD-induced accumulation of human-specific primary bile acids in the cecum.

Advances in Nutrition Science and Integrative Physiology: Insights From Controlled Feeding Studies

Nutrition science is a highly impactful but contentious area of biomedical science. Establishing cause and effect relationships between the nutrients and/or diets we consume and the avoidance of or risk of disease is extremely challenging. As such, evidence-based nutrition is best served by considering the totality of evidence across multiple study types including nutritional epidemiological studies, randomized controlled trials of behavioral interventions, and controlled feeding studies. The purpose of the present review is to provide an overview for those conducting research outside of clinical nutrition on how controlled feeding studies can be used to gain insight into integrative physiology/metabolism as well as to inform dietary guidelines. We discuss the rationale, basic elements, and complexities of conducting controlled feeding studies and provide examples of contributions of controlled feeding studies to advances in nutrition science and integrative physiology. Our goal is to provide a resource for those wishing to leverage the experimental advantage provided by controlled feeding studies in their own research programs.

Saturated Fat: Part of a Healthy Diet

PURPOSE OF REVIEW

Despite the American public following recommendations to decrease absolute dietary fat intake and specifically decrease saturated fat intake, we have seen a dramatic rise over the past 40 years in the rates of non-communicable diseases associated with obesity and overweight, namely cardiovascular disease. The development of the diet-heart hypothesis in the mid twentieth century led to faulty but long-held beliefs that dietary intake of saturated fat led to heart disease. Saturated fat can lead to increased LDL cholesterol levels, and elevated plasma cholesterol levels have been shown to be a risk factor for cardiovascular disease; however, the correlative nature of their association does not assign causation.

RECENT FINDINGS

Advances in understanding the role of various lipoprotein particles and their atherogenic risk have been helpful for understanding how different dietary components may impact CVD risk. Numerous meta-analyses and systematic reviews of both the historical and current literature reveals that the diet-heart hypothesis was not, and still is not, supported by the evidence. There appears to be no consistent benefit to all-cause or CVD mortality from the reduction of dietary saturated fat. Further, saturated fat has been shown in some cases to have an inverse relationship with obesity-related type 2 diabetes. Rather than focus on a single nutrient, the overall diet quality and elimination of processed foods, including simple carbohydrates, would likely do more to improve CVD and overall health. It is in the best interest of the American public to clarify dietary guidelines to recognize that dietary saturated fat is not the villain we once thought it was.

'The hunger trap hypothesis': New horizons in understanding the control of food intake

The global obesity epidemic continues to present significant challenges to individuals and healthcare providers. Public health initiatives to tackle the rise in overweight and obesity in developed and developing nations have largely failed to tackle the problem and research into the underlying causes is of increasing importance. Central to understanding overconsumption of calories is an appreciation of the mechanisms of hunger and satiety. Research to date has revealed considerable detail regarding meal size, macronutrient composition of the diet and control of energy balance via adipose store derived signalling. It is clear however that such control mechanisms are overwhelmed in a significant proportion of the population. We hypothesize the hitherto under-researched possibility that micronutrient status may have an important role in energy balance. Poor vitamin and mineral profiles in the diets of the obese may potentiate overconsumption of calories due to an insufficiency of micronutrient intake relative to macronutrient consumption, a situation aggravated by increased requirements in the obese state. Amongst the multiplicity of metabolic and biochemical processes dependent upon micronutrients and which are impacted by their relative insufficiency, there may be triggers for increased food consumption in an attempt to bridge the gap between high energy consumption and low co-factor availability. This 'hunger trap' will continue as long as low nutrient density foods represent the mainstay of the diet. The accepted paradigm of variety seeking leading to vitamin and mineral adequacy of diets may not apply in the context of highly processed foods which use technological means to mimic organoleptic properties of nutrient density without delivering the same at the level of metabolism.

Genome-nutrition divergence: evolving understanding of the malnutrition spectrum

Humans adapted over a period of 2.3 million years to a diet high in quality and diversity. Genome-nutrition divergence describes the misalignment between modern global diets and the genome formed through evolution. A survey of hominin diets over time shows that humans have thrived on a broad range of foods. Earlier diets were highly diverse and nutrient dense, in contrast to modern food systems in which monotonous diets of staple cereals and ultraprocessed foods play a more prominent role. Applying the lens of genome-nutrition divergence to malnutrition reveals shared risk factors for undernutrition and overnutrition at nutrient, food, and environmental levels. Mechanisms for food system shifts, such as crop-neutral agricultural policy, agroecology, and social policy, are explored as a means to realign modern diets with the nutritional patterns to which humans may be better adapted to thrive.

Setting the Lipid Component of the Diet: A Work in Process

Some of the most relevant yet controversial issues in nutrition are those surrounding the guidelines on quality and quantity of dietary fat in the prevention and treatment of cardiovascular diseases and coronary heart diseases. Conflicting evidence questions the credibility of the previous dietary guidelines, particularly the quality of the evidence on which these recommendations were based. It is therefore important to explore the changes that have occurred in these guidelines and their influence on the adoption of different dietary patterns over time. In this review, we summarize the evolution of the fat component of the dietary guidelines, discuss controversial aspects, and highlight the areas in which additional evidence is still needed. Over the years, the scientific community has shown an obsession for calories in a diet instead of focusing on the quality of the food that makes up the diet. This is why certain authors have identified the importance of evaluating a diet focusing on diet patterns, rather than single isolated nutrients. This approach has been proposed in the most recent Dietary Guidelines for Americans.

Robustness and evidence of mechanisms in early experimental atherosclerosis research

This article considers the evaluation of experimental evidence for a causal relation between cholesterol and atherosclerosis from the beginning of the 1900s until the late 1950s. It has been argued that the medical community failed to see the implications of this early research, and at first unjustifiably rejected a causal link between cholesterol and atherosclerosis. This article argues to the contrary that the medical community was justified to conclude based on the experimental evidence that cholesterol (dietary or blood) is probably not an effective target for preventive treatment. However, the evidence would have been sufficient to ascribe to cholesterol a contributing causal role in atherosclerotic heart disease. This view is argued for based on a rational reconstruction of the researchers' evaluation of evidence, specifically, the robustness of evidence for a manipulable dependence between cholesterol and atherosclerosis on the one hand, and the evidence for a mediating mechanism on the other. The case study is used to illustrate that robustness is a feasible methodological principle even when evidence is discordant, and evidence of mechanism should be evaluated on a par with evidence of statistical dependence in establishing causal claims.

Regular-Fat Dairy and Human Health: A Synopsis of Symposia Presented in Europe and North America (2014-2015)

In recent history, some dietary recommendations have treated dairy fat as an unnecessary source of calories and saturated fat in the human diet. These assumptions, however, have recently been brought into question by current research on regular fat dairy products and human health. In an effort to disseminate, explore and discuss the state of the science on the relationship between regular fat dairy products and health, symposia were programmed by dairy industry organizations in Europe and North America at The Eurofed Lipids Congress (2014) in France, The Dairy Nutrition Annual Symposium (2014) in Canada, The American Society for Nutrition Annual Meeting held in conjunction with Experimental Biology (2015) in the United States, and The Federation of European Nutrition Societies (2015) in Germany. This synopsis of these symposia describes the complexity of dairy fat and the effects regular-fat dairy foods have on human health. The emerging scientific evidence indicates that the consumption of regular fat dairy foods is not associated with an increased risk of cardiovascular disease and inversely associated with weight gain and the risk of obesity. Dairy foods, including regular-fat milk, cheese and yogurt, can be important components of an overall healthy dietary pattern. Systematic examination of the effects of dietary patterns that include regular-fat milk, cheese and yogurt on human health is warranted.

Egg Consumption and Human Cardio-Metabolic Health in People with and without Diabetes

The guidelines for dietary cholesterol and/or egg intake for both the general population and those at higher risk of cardiovascular disease (for example, people with type 2 diabetes mellitus (T2DM)) differ between countries, and even for different specialist societies in a country. The disparity between these guidelines is at least in part related to the conflicting evidence as to the effects of eggs in the general population and in those with T2DM. This review addresses the effect of eggs on cardiovascular disease (CVD) risk from both epidemiological research and controlled prospective studies, in people with and without cardio-metabolic disease. It also examines the nutritional qualities of eggs and whether they may offer protection against chronic disease. The evidence suggests that a diet including more eggs than is recommended (at least in some countries) may be used safely as part of a healthy diet in both the general population and for those at high risk of cardiovascular disease, those with established coronary heart disease, and those with T2DM. In conclusion, an approach focused on a person's entire dietary intake as opposed to specific foods or nutrients should be the heart of population nutrition guidelines.

Fatty acids linked to cardiovascular mortality are associated with risk factors

Background

Although saturated fatty acids (FAs) have been linked to cardiovascular mortality, it is not clear whether this outcome is attributable solely to their effects on low-density lipoprotein cholesterol (LDL-C) or whether other risk factors are also associated with FAs. The Western Alaskan Native population, with its rapidly changing lifestyles, shift in diet from unsaturated to saturated fatty acids and dramatic increase in cardiovascular disease (CVD), presents an opportunity to elucidate any associations between specific FAs and known CVD risk factors.

Objective

We tested the hypothesis that the specific FAs previously identified as related to CVD mortality are also associated with individual CVD risk factors.

Methods

In this community-based, cross-sectional study, relative proportions of FAs in plasma and red blood cell membranes were compared with CVD risk factors in a sample of 758 men and women aged ≥35 years. Linear regression analyses were used to analyze relations between specific FAs and CVD risk factors (LDL-C, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, systolic blood pressure, diastolic blood pressure, heart rate, body mass index, fasting glucose and fasting insulin, 2-hour glucose and 2-hour insulin).

Results

The specific saturated FAs previously identified as related to CVD mortality, the palmitic and myristic acids, were adversely associated with most CVD risk factors, whereas unsaturated linoleic acid (18:2n-6) and the marine n-3 FAs were not associated or were beneficially associated with CVD risk factors.

Conclusions

The results suggest that CVD risk factors are more extensively affected by individual FAs than hitherto recognized, and that risk for CVD, MI and stroke can be reduced by reducing the intake of palmitate, myristic acid and simple carbohydrates and improved by greater intake of linoleic acid and marine n-3 FAs.

Excessive dietary linoleic acid induces proinflammatory markers in rats

Following the historical dietary recommendations, the substitution of polyunsaturated fatty acids (PUFAs) for saturated fatty acids (SFAs) resulted in a dramatic increase of linoleic acid (LA) in the Western diet. While proatherogenic properties of SFAs have been described, the involvement of LA on the inflammatory process remains controversial. Herein, we evaluated the effects of an excessive LA intake on the cytokine-induced expression of endothelial adhesion molecules vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1), through the nuclear factor (NF)-κB pathway, in comparison with a control diet and regarding a "positive" SFA diet. Wistar rats were fed experimental diets - a control diet or diets enriched with LA or SFA - for 11 weeks. Plasma lipid parameters and proinflammatory cytokine production such as interleukin-1β and tumor necrosis factor (TNF)-α were analyzed. Expression of endothelial adhesion molecules and NF-κB was determined by immunohistochemical analysis. No difference was observed in body weight. The enriched diets did not affect triglyceride and total cholesterol levels in plasma. Our results demonstrated that excessive dietary LA intake increased TNF-α levels (P<.05) in plasma. Rats fed the LA-enriched diet showed a significantly higher expression of VCAM-1, ICAM-1 and NF-κB in aortas. In addition, our results demonstrated that an excess of LA is more efficient to activate endothelial molecular process than an excess of SFA. The present study provides further support for the proinflammatory properties of LA and suggests an LA-derivatives pathway involved in the inflammatory process.

Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver

The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose. Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic. Here, we designed a series of four isocaloric diets (HFD, SO-HFD, F-HFD, F-SO-HFD) to investigate the effects of saturated versus unsaturated fat, as well as fructose, on obesity and diabetes. C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD). They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length. While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury. The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight. Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.

Dietary saturated fat intake and atherosclerotic vascular disease mortality in elderly women: a prospective cohort study

BACKGROUND

The reduction of saturated fatty acid (SFA) intake has been the basis of long-standing dietary recommendations. However, recent epidemiologic studies have reported conflicting evidence in the relation between SFA consumption and risk of atherosclerotic vascular disease (ASVD) mortality.

OBJECTIVE

We investigated the association of SFA intake with serum lipid profiles and ASVD mortality in a population-based 10-y cohort study.

DESIGN

At baseline (1998) 1469 women living in Perth, Western Australia, with a mean ± SD age of 75.2 ± 2.7 y had SFA intake measured by using a validated food-frequency questionnaire. Outcome data were serum lipids at baseline and ASVD deaths over 10 y (13,649 person-years of follow-up), retrieved from the Western Australian Data Linkage System. Other risk factors for ASVD were assessed and adjusted for in multivariable analyses.

RESULTS

ASVD deaths occurred in 9.1% (134) of participants. The highest quartile of SFA intake (>31.28 g/d) had an ~16% cumulative mortality risk compared with ~5% in the lowest quartile (<17.39 g/d) (HR: 3.07; 95% CI: 1.54, 6.11; P = 0.001). Baseline SFA intake was associated with baseline serum total and LDL cholesterol in multivariable-adjusted models (β: 0.199, SE: 0.056, P < 0.001 and β: 0.190, SE: 0.051, P < 0.001, respectively). However, baseline serum total and LDL cholesterol were not associated with ASVD mortality.

CONCLUSIONS

High SFA intake was associated with the risk of ASVD mortality in this population of elderly women. Although there was a strong positive association between SFA intake and LDL cholesterol, LDL cholesterol was not associated with ASVD mortality in this cohort. Nevertheless, these data support dietary advice to reduce SFA intake.

Challenges of utilizing healthy fats in foods

Over the past few decades, the Dietary Guidelines for Americans has consistently recommended that consumers decrease consumption of saturated fatty acids due to the correlation of saturated fatty acid intake with coronary artery disease. This recommendation has not been easy to achieve because saturated fatty acids play an important role in the quality, shelf life, and acceptability of foods. This is because solid fats are critical to producing desirable textures (e.g., creaminess, lubrication, and melt-away properties) and are important in the structure of foods such as frozen desserts, baked goods, and confectionary products. In addition, replacement of saturated fats with unsaturated fats is limited by their susceptibility to oxidative rancidity, which decreases product shelf life, causes destruction of vitamins, and forms potentially toxic compounds. This article will discuss the fundamental chemical and physical properties in fats and how these properties affect food texture, structure, flavor, and susceptibility to degradation. The current sources of solid fats will be reviewed and potential replacements for solid fats will be discussed.

Statistical review of US macronutrient consumption data, 1965-2011: Americans have been following dietary guidelines, coincident with the rise in obesity

BACKGROUND

For almost 50 y, the US National Health and Nutrition Examination Survey (NHANES) has measured the caloric consumption, and body heights and weights of Americans. The aim of this study was to determine, based on that data, how macronutrient consumption patterns and the weight and body mass index in the US adult population have evolved since the 1960s.

METHODS

We conducted the first comprehensive analysis of the NHANES data, documenting how macronutrient consumption patterns and the weight and body mass index in the US adult population have evolved since the 1960s.

RESULTS

Americans in general have been following the nutrition advice that the American Heart Association and the US Departments of Agriculture and Health and Human Services have been issuing for more than 40 y: Consumption of fats has dropped from 45% to 34% with a corresponding increase in carbohydrate consumption from 39% to 51% of total caloric intake. In addition, from 1971 to 2011, average weight and body mass index have increased dramatically, with the percentage of overweight or obese Americans increasing from 42% in 1971 to 66% in 2011.

CONCLUSIONS

Since 1971, the shift in macronutrient share from fat to carbohydrate is primarily due to an increase in absolute consumption of carbohydrate as opposed to a change in total fat consumption. General adherence to recommendations to reduce fat consumption has coincided with a substantial increase in obesity.

Food for thought: dietary changes in essential fatty acid ratios and the increase in autism spectrum disorders

The last decades have shown a spectacular and partially unexplained rise in the prevalence of autism spectrum disorders (ASD). This rise in ASD seems to parallel changes in the dietary composition of fatty acids. This change is marked by the replacement of cholesterol by omega-6 (n-6) fatty acids in many of our food products, resulting in a drastically increased ratio of omega-6/omega-3 (n-6/n-3). In this context, we review the available knowledge on the putative role of fatty acids in neurodevelopment and describe how disturbances in n-6/n-3 ratios may contribute to the emergence of ASDs. Both clinical and experimental research is discussed. We argue that a change in the ratio of n-6/n-3, especially during early life, may induce developmental changes in brain connectivity, synaptogenesis, cognition and behavior that are directly related to ASD.

Differential responses to docosahexaenoic acid in primary and immortalized cardiac cells

The importance of dietary polyunsaturated fatty acids (PUFAs) in the reduction of cardiovascular disease has been recognized for many years. Docosahexaenoic acid (22:6n3, DHA) is an n-3 PUFA known to affect numerous biological functions and provide cardioprotection; however, the exact molecular and cellular protective mechanism(s) remain unknown. In contrast, DHA also possesses many anti-tumorgenic properties including suppressing cell growth and inducing apoptosis. In the present study, we investigated the effect of DHA toward H9c2 cells (an immortalized cardiac cell line) and neonatal primary cardiomyocytes (NCM). Cells were treated with 0μM, 10μM or 100μM DHA for upto 48h. Cell viability and mitochondrial activity were assayed at different time points. DHA caused a significant time- and dose-dependent decrease in cell viability and mitochondrial activity in H9c2 cells but not NCM. In addition, DHA decreased levels of TGF-β1 but increased IL-6 release in H9c2 cells. Significant induction of apoptosis was observed only in H9c2 cells, which involved activation of caspase-8 and -3 activities with a marked release of cytochrome c from mitochondria. DHA-induced severe mitochondrial damage resulting in a fragmented and punctated morphology with corresponding loss of mitochondrial membrane potential within 3h, prior to activation of caspases and cytochrome c release at 6h in H9c2 cells. Our data indicate that DHA treatment targets mitochondria, triggering collapse of mitochondrial membrane potential, increasing cellular stress and mitochondrial fragmentation resulting in apoptosis in immortalized cardiac cells, H9c2, but not neonatal primary cardiomyocyte.

Recommended dietary reference intakes, nutritional goals and dietary guidelines for fat and fatty acids: a systematic review

Dietary fat and its effects on health and disease has attracted interest for research and Public Health. Since the 1980s many bodies and organizations have published recommendations regarding fat intake. In this paper different sets of recommendations are analyzed following a systematic review process to examine dietary reference intakes, nutritional goals and dietary guidelines for fat and fatty acids. A literature search was conducted in relevant literature databases along a search for suitable grey literature reports. Documents were included if they reported information on either recommended intake levels or dietary reference values or nutritional objectives or dietary guidelines regarding fat and/or fatty acids and/or cholesterol intake or if reported background information on the process followed to produce the recommendations. There is no standard approach for deriving nutrient recommendations. Recommendations vary between countries regarding the levels of intake advised, the process followed to set the recommendations. Recommendations on fat intake share similar figures regarding total fat intake, saturated fats andtransfats. Many sets do not include a recommendation about cholesterol intake. Most recent documents provide advice regarding specificn-3 fatty acids. Despite efforts to develop evidence based nutrient recommendations and dietary guidelines that may contribute to enhance health, there are still many gaps in research. It would be desirable that all bodies concerned remain transparent about the development of dietary recommendations. In order to achieve this, the type of evidence selected to base the recommendations should be specified and ranked. Regular updates of such recommendations should be planned.

Dietary linoleic acid has no effect on arachidonic acid, but increases n-6 eicosadienoic acid, and lowers dihomo-gamma-linolenic and eicosapentaenoic acid in plasma of adult men

High intakes of linoleic acid (LA,18:2n-6) have raised concern due to possible increase in arachidonic acid (ARA, 20:4n-6) synthesis, and inhibition of alpha linolenic acid (ALA, 18:3n-3) desaturation to eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). In healthy men, 10.5% energy compared to 3.8% energy LA with 1% energy ALA increased plasma phospholipid LA and 20:2n-6, the elongation product of LA, and decreased EPA, with no change in ARA. However, LA was inversely related to ARA at both 10.5% energy and 3.8% energy LA, (r=-0.761, r=-0.817, p<0.001, respectively). A two-fold variability in ARA among individuals was not explained by the dietary LA, ARA, ALA, or fish intake. Our results confirm LA requirements for ARA synthesis is low, <3.8% energy, and they suggest current LA intakes saturate Delta-6 desaturation and adversely affect n-3 fatty acid metabolism. Factors other than n-6 fatty acid intake are important modifiers of plasma ARA.

Dietary omega 3 fatty acids and the developing brain

The omega-3 fatty acids are essential dietary nutrients and one of their important roles is providing the fatty acid with 22 carbons and 6 double bonds known as docosahexaenoic acid (DHA) for nervous tissue growth and function. Inadequate intakes of omega-3 fatty acids decrease DHA and increase omega-6 fatty acids in the brain. Decreased DHA in the developing brain leads to deficits in neurogenesis, neurotransmitter metabolism, and altered learning and visual function in animals. Western diets are low in omega-3 fatty acids, including the 18 carbon omega-3 fatty acid alpha linolenic acid found mainly in plant oils, and DHA, which is found mainly in fish. The DHA status of the newborn and breast-fed infant depends on the maternal intake of DHA and varies widely. Epidemiological studies have linked low maternal DHA to increased risk of poor child neural development. Intervention studies have shown improving maternal DHA nutrition decreases the risk of poor infant and child visual and neural development. Thus, sufficient evidence is available to conclude that maternal fatty acid nutrition is important to DHA transfer to the infant before and after birth, with short and long-term implications for neural function. However, genetic variation in genes encoding fatty acid desaturases also influence essential fatty acid metabolism, and may increase requirements in some individuals. Consideration of omega-3 fatty acid to include brain development, optimizing omega-3 and omega-6 fatty acids in gestation and lactation, and in fatty acid nutrition support for intravenous and formula-fed neonates is important.

Too much linoleic acid promotes inflammation-doesn't it?

Controversy exists over how much linoleic acid (LA) should be consumed in a healthy diet. Some claim that high LA intake promotes inflammation through accumulation of tissue arachidonic acid (AA) and subsequent production of pro-inflammatory lipid mediators. Here the author reviews the current available evidence from human studies that address this issue. The data indicate that high LA in the diet or circulation is not associated with higher in vivo or ex vivo pro-inflammatory responses. Surprisingly, several studies showed that those individuals consuming the highest level of LA had the lowest inflammatory status. Recent findings suggest that LA and AA are involved in both pro- and anti-inflammatory signaling pathways. Thus, within the ranges of intake that are achievable for most human populations, the evidence do not support reducing LA intake below current consumption levels.

High dietary omega-6 fatty acids contribute to reduced docosahexaenoic acid in the developing brain and inhibit secondary neurite growth

Docosahexaenoic acid (DHA, 22:6omega-3) is a major polyunsaturated fatty acid in the brain and is required in large amounts during development. Low levels of DHA in the brain are associated with functional deficits. The omega-3 fatty acids are essential nutrients and their metabolism and incorporation in developing brain depends on the composition of dietary fat. We assessed the importance of the intake of the omega-3 fatty acid, 18:3omega-3 and the balance with the omega-6 fatty acid, 18:2omega-6, and the effects of dietary arachidonic acid (20:4omega-6) and DHA in milk diets using the piglet as a model of early infant nutrition. Piglets were fed (% energy) 1.2% 18:2omega-6 and 0.05% 18:3omega-3 (deficient), 10.7% 18:2omega-6 and 1.1% 18:3omega-3 (contemporary), 1.2% 18:2omega-6 and 1.1% 18:3omega-3 (evolutionary), or the contemporary diet with 0.3% 20:4omega-6 and 0.3% DHA (supplemented) from birth to 30 days of age. Our results show that a contemporary diet, high in 18:2omega-6 compromises DHA accretion and leads to increased 22:4omega-6 and 22:5omega-6 in the brain. However, an evolutionary diet, low in 18:2omega-6, supports high brain DHA. DHA supplementation effectively increased DHA, but not the intermediate omega-3 fatty acids, 20:5omega-3 and 22:5omega-3. Using primary cultures of cortical neurons, we show that 22:5omega-6 is efficiently acylated and preferentially taken up over DHA. However, DHA, but not 22:5omega-6 supports growth of secondary neurites. Our results suggest the need to consider whether current high dietary omega-6 fatty acid intakes compromise brain DHA accretion and contribute to poor neurodevelopment.

Cardiovascular event risk in relation to dietary fat intake in middle-aged individuals: data from The Malmö Diet and Cancer Study

BACKGROUND AND DESIGN

The hypothesis that diets rich in total and saturated fat and poor in unsaturated fats increase the risk for cardiovascular disease is still vividly debated. The aim of this study was to examine whether total fat, saturated fat, or unsaturated fat intakes are independent risk factors for cardiovascular events in a large population-based cohort.

METHODS

28 098 middle-aged individuals (61% women) participated in the Malmö Diet and Cancer Study between 1991 and 1996. In this analysis, individuals with an earlier history of cardiovascular disease were excluded. With adjustments made for confounding by age and various anthropometric, social, dietary, and life-style factors, hazard ratios (HR) were estimated for individuals categorized by quartiles of fat intake [HR (95% confidence interval, CI), Cox's regression model].

RESULTS

No trend towards higher cardiovascular event risk for women or men with higher total or saturated fat intakes, was observed. Total fat: HR (95% CI) for fourth quartile was 0.98 (0.77-1.25) for women, 1.02 (0.84-1.23) for men; saturated fat: 0.98 (0.71-1.33) for women and 1.05 (0.83-1.34) for men. Inverse associations between unsaturated fat intake and cardiovascular event risk were not observed.

CONCLUSIONS

In relation to risks of cardiovascular events, our results do not suggest any benefit from a limited total or saturated fat intake, nor from relatively high intake of unsaturated fat.

Dietary fat intake and early mortality patterns--data from The Malmö Diet and Cancer Study

OBJECTIVES

Most current dietary guidelines encourage limiting relative fat intake to <30% of total daily energy, with saturated and trans fatty acids contributing no more than 10%. We examined whether total fat intake, saturated fat, monounsaturated, or polyunsaturated fat intake are independent risk factors for prospective all-cause, cardiovascular and cancer mortality.

DESIGN

Population-based, prospective cohort study.

SETTING AND SUBJECTS

The Malmö Diet and Cancer Study was set in the city of Malmö, southern Sweden. A total of 28,098 middle-aged individuals participated in the study 1991-1996.

MAIN OUTCOME MEASURES

Subjects were categorized by quartiles of relative fat intake, with the first quartile used as a reference point in estimating multivariate relative risks (RR; 95% CI, Cox's regression model). Adjustments were made for confounding by age and various lifestyle factors.

RESULTS

Women in the fourth quartile of total fat intake had a significantly higher RR of cancer mortality (RR 1.46; CI 1.04-2.04). A significant downwards trend was observed for cardiovascular mortality amongst men from the first to the fourth quartile (P=0.028). No deteriorating effects of high saturated fat intake were observed for either sex for any cause of death. Beneficial effects of a relatively high intake of unsaturated fats were not uniform.

CONCLUSIONS

With the exception of cancer mortality for women, individuals receiving more than 30% of their total daily energy from fat and more than 10% from saturated fat, did not have increased mortality. Current dietary guidelines concerning fat intake are thus generally not supported by our observational results.

A Review of Scientific Research and Recommendations Regarding Eggs

For much of the past 40 years, the public has been warned away from eggs because of a concern over coronary heart disease risk. This concern is based on three observations: 1. eggs are a rich source of dietary cholesterol; 2. when fed experimentally, dietary cholesterol increases serum cholesterol and; 3. high serum cholesterol predicts the onset of coronary heart disease. However, data from free-living populations show that egg consumption is not associated with higher cholesterol levels. Furthermore, as a whole, the epidemiologic literature does not support the idea that egg consumption is a risk factor for coronary disease. Within the nutritional community there is a growing appreciation that health derives from an overall pattern of diet rather than from the avoidance of particular foods, and there has been a shift in the tone in recent dietary recommendations away from "avoidance" messages to ones that promote healthy eating patterns. The most recent American Heart Association guidelines no longer include a recommendation to limit egg consumption, but recommend the adoption of eating practices associated with good health. Based on the epidemiologic evidence, there is no reason to think that such a healthy eating pattern could not include eggs.

Children's dietary fat intake and fat practices vary by meal and day

OBJECTIVE

This research examined the relationship between the dietary fat intake and fat practices of children by meal, day of week, and weekend day vs weekday.

DESIGN

Cross-sectional study.

SUBJECTS/SETTING

Fourth- to sixth-grade students (n = 520; 25% African-American, 32% white, 33% Mexican-American, 10% Asian/other, 58% girls) attending 8 parochial schools in Houston, Texas.

MAIN MEASURES

Students completed daily food records in the classroom for 7 days. Food records were hand-coded for high-fat (eg, frying foods, adding fat) and low-fat (eg, removing meat fat, drinking low-fat milk) practices, and percent energy from fat.

STATISTICAL ANALYSES

Descriptive statistics, Spearman correlation coefficients, and analysis of variance on fat intake and fat practices by demographic variables and weekend vs weekday.

RESULTS

Students consumed 36% of total energy from fat, reported 0.59 low-fat practices, and 6.3 high-fat practices per day. Only 13% consumed 30% or less energy from fat. Significant correlations were found between percent energy from fat and high-fat practices and low-fat practices (r = 0.27, P < .001 and r = -0.15, P < .01, respectively).

APPLICATIONS/CONCLUSIONS

Intervention programs targeting children's dietary fat behaviors should include teaching skills that enable children to ask for low-fat foods like fruit, vegetables, low-fat snacks and dairy foods. These foods should be made available in the home to encourage children to practice low-fat dietary behaviors, which may differ depending on meal, day, and meal source.

Familial concordance of dietary fat practices and intake

This study examined parent and child dietary fat practices and child dietary fat intake. High- and low-fat practices and percentage of kilocalories from fat were obtained from food records completed by 132 students in the 4th to 6th grades. Parents completed three scales: meat modifications (MMOD); fat substitutions (FSUB); and fruit, juice, and vegetable practices (FJVP). A parent low-fat practices (PLFP) scale was created with the items matching the child low-fat practices (LFPs). Parent PLFP, FSUB, and FJVP were significantly correlated with child LFPs. Parent LFP was a significant predictor of child LFP. Family intervention programs targeting dietary fat behaviors should encourage use of low-fat dietary behaviors.

Choose a diet that is low in saturated fat and cholesterol and moderate in total fat: subtle changes to a familiar message

"Choose a diet that is low in saturated fat and cholesterol and moderate in total fat," issued in Nutrition and Your Health: Dietary Guidelines for Americans in the year 2000, has an interesting and lengthy history. The first guideline, for which there was extensive scientific data to show that dietary excess increased chronic disease risk, prompted much scientific discussion and debate when implemented as dietary guidance. Three major changes in the guideline are noted since it was issued in 1980, i.e., numerical goals for dietary fats; the applicability of recommended fat intakes for all individuals > or =2 y old; and rewording to emphasize reducing saturated fat and cholesterol intakes. The shift in emphasis includes the terminology moderate fat, which replaces the phrasing low fat. National data about the food supply, the population's dietary intake, knowledge, attitudes and behaviors, and nutritional status indicators (e.g., serum cholesterol levels) related to dietary fats help to monitor nutrition and health in the population. Experts consider that national data, although not without limitations, are sufficient to conclude that U.S. intakes of fats, as a proportion of energy, have decreased. The lower intakes of saturated fat and cholesterol are consistent with decreases in blood cholesterol levels and lower rates of coronary mortality over the past 30 years. Strategies are needed and some are suggested, to further encourage the population to achieve a dietary pattern that is low in saturated fat and cholesterol and moderate in total fat. Other suggestions are offered to improve national nutrition monitoring and surveillance related to the guideline.

Ácidos graxos e doenças cardiovasculares: uma revisão

Nas últimas décadas a prevalência de doenças cardiovasculares tem aumentado progressivamente, tornando-se um grave problema de saúde pública. Alguns estudos têm demonstrado haver uma associação positiva entre a ingestão de gordura saturada e a prevalência dessas doenças, bem como uma associação negativa com a ingestão de gorduras insaturadas. Esses conhecimentos motivaram uma evolução nas recomendações dos ácidos graxos, visando melhor utilização destes e respeitando-se uma proporção adequada na dieta, a fim de diminuir a prevalência das doenças cardiovasculares. Este trabalho tem como objetivo realizar uma revisão da literatura médica sobre os estudos desenvolvidos com ácidos graxos e seus possíveis efeitos em doenças cardiovasculares, bem como evolução de suas recomendações através do tempo, tendências de consumo e perspectivas futuras.

Position of the American Dietetic Association and Dietitians of Canada: women's health and nutrition

Within the past 10 years women's health has evolved to a much broader paradigm, beyond reproductive issues. From a physiological perspective, women's health now refers to the prevention, diagnosis, and management of conditions or diseases that may be unique to women, be more prevalent in women, or manifest differently in women than men. Women's health encompasses emotional, social, cultural, spiritual, and physical well-being. It is determined by the social, political, and economic context of women's lives. Nutrition is involved in the etiology or treatment of half of the 10 leading causes of death in women. The incidence of osteoporosis and extremes in body weight are approaching epidemic proportions in women. This position reviews the following health problems: cardiovascular disease, cancer, osteoporosis, weight, and diabetes mellitus. Dietetics professionals are in the perfect position to understand the issues surrounding women's health in order to deliver a message to women that will allow them to make wise decisions regarding their health. Nutrition is a critical component of risk reduction and treatment, and must be included in clinical and preventive services for women. Dietetics professionals must work to increase their knowledge about women's health issues, to promote health and education programs, to influence policy makers, to deliver the highest-quality medical nutrition therapy, and to be proactive in documenting the effectiveness of outcomes-based research.