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Nature Reviews. Gastroenterology &... Nov 2021The global prevalence of nonalcoholic fatty liver disease (NAFLD) has dramatically increased in parallel with the epidemic of obesity. Controversy has emerged around... (Review)
Review
The global prevalence of nonalcoholic fatty liver disease (NAFLD) has dramatically increased in parallel with the epidemic of obesity. Controversy has emerged around dietary guidelines recommending low-fat-high-carbohydrate diets and the roles of dietary macronutrients in the pathogenesis of metabolic disease. In this Review, the topical questions of whether and how dietary fats and carbohydrates, including free sugars, differentially influence the accumulation of liver fat (specifically, intrahepatic triglyceride (IHTG) content) are addressed. Focusing on evidence from humans, we examine data from stable isotope studies elucidating how macronutrients regulate IHTG synthesis and disposal, alter pools of bioactive lipids and influence insulin sensitivity. In addition, we review cross-sectional studies on dietary habits of patients with NAFLD and randomized controlled trials on the effects of altering dietary macronutrients on IHTG. Perhaps surprisingly, evidence to date shows no differential effects between free sugars, with both glucose and fructose increasing IHTG in the context of excess energy. Moreover, saturated fat raises IHTG more than polyunsaturated or monounsaturated fats, with adverse effects on insulin sensitivity, which are probably mediated in part by increased ceramide synthesis. Taken together, the data support the use of diets that have a reduced content of free sugars, refined carbohydrates and saturated fat in the treatment of NAFLD.
Topics: Ceramides; Dietary Carbohydrates; Dietary Fats; Dietary Fats, Unsaturated; Dietary Sugars; Fructose; Glucose; Humans; Insulin Resistance; Liver; Non-alcoholic Fatty Liver Disease; Triglycerides
PubMed: 34257427
DOI: 10.1038/s41575-021-00472-y -
Nutrients Sep 2021The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack... (Review)
Review
The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S. Dietary Guidelines for Americans, the country's national nutrition policy, which recently reconfirmed its recommendation to limit saturated fats to 10% or less of total energy intake, based on insufficient and inconsistent evidence. Continuation of a cap on saturated fat intake also fails to consider the important effects of the food matrix and the overall dietary pattern in which saturated fatty acids are consumed.
Topics: Clinical Trials as Topic; Diet; Dietary Fats; Health; Humans; Nutrition Policy; United States
PubMed: 34684304
DOI: 10.3390/nu13103305 -
Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function.Nutrients Oct 2019Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a... (Review)
Review
Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a vitally important energy source; it affects brain function and provides direct energy. Several studies have indicated that high-fat consumption causes overproduction of circulating free fatty acids and systemic inflammation. Immune cells, free fatty acids, and circulating cytokines reach the hypothalamus and initiate local inflammation through processes such as microglial proliferation. Therefore, the role of high-fat diet (HFD) in promoting oxidative stress and neurodegeneration is worthy of further discussion. Of particular interest in this article, we highlight the associations and molecular mechanisms of HFD in the modulation of inflammation and cognitive deficits. Taken together, a better understanding of the role of oxidative stress in cognitive impairment following HFD consumption would provide a useful approach for the prevention of cognitive dysfunction.
Topics: Cell Proliferation; Cognition; Cognitive Dysfunction; Diet, High-Fat; Dietary Fats; Humans; Inflammation; Oxidative Stress
PubMed: 31731503
DOI: 10.3390/nu11112579 -
Nutrients Oct 2019Currently available pharmacological treatment of epilepsy has limited effectiveness. In epileptic patients, pharmacological treatment with available anticonvulsants... (Review)
Review
Currently available pharmacological treatment of epilepsy has limited effectiveness. In epileptic patients, pharmacological treatment with available anticonvulsants leads to seizure control in <70% of cases. Surgical intervention can lead to control in a selected subset of patients, but still leaves a significant number of patients with uncontrolled seizures. Therefore, in drug-resistant epilepsy, the ketogenic diet proves to be useful. The purpose of this review was to provide a comprehensive overview of what was published about the benefits of ketogenic diet treatment in patients with epilepsy. Clinical data on the benefits of ketogenic diet treatment in terms of clinical symptoms and adverse reactions in patients with epilepsy have been reviewed. Variables that could have influenced the interpretation of the data were also discussed (e.g., gut microbiota). The data in this review contributes to a better understanding of the potential benefits of a ketogenic diet in the treatment of epilepsy and informs scientists, clinicians, and patients-as well as their families and caregivers-about the possibilities of such treatment. Since 1990, the number of publications on attempts to treat drug-resistant epilepsy with a ketogenic diet has grown so rapidly that it has become a challenge to see the overall trajectory and major milestones achieved in this field. In this review, we hope to provide the latest data from randomized clinical trials, practice guidelines, and new research areas over the past 2 years.
Topics: Anticonvulsants; Diet, Ketogenic; Dietary Fats; Drug Resistant Epilepsy; Humans
PubMed: 31635247
DOI: 10.3390/nu11102510 -
Journal of Nutritional Science 2023Whilst dietary cholesterol guidelines have waivered through the years with historic restrictions lifted for the majority of the general population, recommendations to... (Review)
Review
Whilst dietary cholesterol guidelines have waivered through the years with historic restrictions lifted for the majority of the general population, recommendations to reduce saturated fat intake have been the mainstay of dietary guidelines since the 1980s and were recently reinforced by the Scientific Advisory Committee on Nutrition (SACN). Cholesterol metabolism is complex, with saturated fat known to have a more significant contribution at raising levels of low-density lipoprotein (LDL) cholesterol, a well-established risk factor for cardiovascular disease (CVD). However, it is clear from metabolic research that hyper-responsiveness to both dietary cholesterol and saturated fat exists; hence, for specific subsets of the population, reductions in both nutrients may be indicated. With this in mind, the current article aims to provide an overview of the mechanisms underlying biological variation in responsiveness and introduces research currently underway which will hopefully identify simple biomarkers that can be used to predict responsiveness and permit tailored, personalised, dietary advice. Eggs are a well-known source of dietary cholesterol whilst being low in saturated fat. A common question encountered in clinical practice is must individuals limit intake to manage blood cholesterol levels. This article summarises key recent papers which confirm that eggs can be enjoyed as part of a healthy balanced diet, whilst highlighting the need for further research in certain population groups, e.g. in individuals with diabetes.
Topics: Humans; Dietary Fats; Cholesterol, Dietary; Cardiovascular Diseases; Cholesterol; Diet
PubMed: 37706071
DOI: 10.1017/jns.2023.82 -
Current Atherosclerosis Reports May 2023This narrative review summarizes the current peer-reviewed literature and mechanisms surrounding the cardiovascular health impact of coconut oil. (Review)
Review
PURPOSE OF REVIEW
This narrative review summarizes the current peer-reviewed literature and mechanisms surrounding the cardiovascular health impact of coconut oil.
RECENT FINDINGS
No randomized controlled trials (RCTs) and/or prospective cohort studies have investigated the effect or association of coconut oil with cardiovascular disease. Evidence from RCTs indicated that coconut oil seems to have less detrimental effects on total and LDL-cholesterol compared to butter, but not compared to cis-unsaturated vegetable oils, such as safflower, sunflower, or canola oil. The isocaloric replacement (by 1% of energy intake) of carbohydrates with lauric acid (the predominant fatty acid in coconut oil) increased total cholesterol by 0.029 mmol/L (95% CI: 0.014; 0.045), LDL-cholesterol by 0.017 mmol/L (0.003; 0.031), and HDL-cholesterol by 0.019 mmol/L (0.016; 0.023). The current evidence from shorter term RCTs suggests that replacement of coconut oil with cis-unsaturated oils lowers total and LDL-cholesterol, whereas for the association between coconut oil intake and cardiovascular disease, less evidence is available.
Topics: Humans; Coconut Oil; Dietary Fats; Cardiovascular Diseases; Plant Oils; Cholesterol, LDL; Triglycerides
PubMed: 36971981
DOI: 10.1007/s11883-023-01098-y -
International Journal of Molecular... Jun 2020A high-fat diet (HFD) induces changes in gut microbiota leading to activation of pro-inflammatory pathways, and obesity, as a consequence of overnutrition, exacerbates... (Review)
Review
A high-fat diet (HFD) induces changes in gut microbiota leading to activation of pro-inflammatory pathways, and obesity, as a consequence of overnutrition, exacerbates inflammation, a known risk factor not only for cancer. However, experimental data showed that the composition of dietary fat has a greater impact on the pathogenesis of cancer than the total fat content in isocaloric diets. Similarly, human studies did not prove that a decrease in total fat intake is an effective strategy to combat cancer. Saturated fat has long been considered as harmful, but the current consensus is that moderate intake of saturated fatty acids (SFAs), including palmitic acid (PA), does not pose a health risk within a balanced diet. In regard to monounsaturated fat, plant sources are recommended. The consumption of plant monounsaturated fatty acids (MUFAs), particularly from olive oil, has been associated with lower cancer risk. Similarly, the replacement of animal MUFAs with plant MUFAs decreased cancer mortality. The impact of polyunsaturated fatty acids (PUFAs) on cancer risk depends on the ratio between ω-6 and ω-3 PUFAs. In vivo data showed stimulatory effects of ω-6 PUFAs on tumour growth while ω-3 PUFAs were protective, but the results of human studies were not as promising as indicated in preclinical reports. As for trans FAs (TFAs), experimental data mostly showed opposite effects of industrially produced and natural TFAs, with the latter being protective against cancer progression, but human data are mixed, and no clear conclusion can be made. Further studies are warranted to establish the role of FAs in the control of cell growth in order to find an effective strategy for cancer prevention/treatment.
Topics: Animals; Diet, High-Fat; Diet, Mediterranean; Dietary Fats; Fats; Fatty Acids, Unsaturated; Gastrointestinal Microbiome; Humans; Inflammation; Lipid Metabolism; Neoplasms; Obesity; Oxidative Stress; Xenobiotics
PubMed: 32526973
DOI: 10.3390/ijms21114114 -
Journal of Animal Science Apr 2020Fatty acids (FA) play a major role in relation to mucosal immune responses, epithelial barrier functions, oxidative stress, and inflammatory reactions. The dietary FA... (Review)
Review
Fatty acids (FA) play a major role in relation to mucosal immune responses, epithelial barrier functions, oxidative stress, and inflammatory reactions. The dietary FA composition and the molecular structures (chain length and number of double bonds) influence digestion, absorption and metabolism, and the bioactivity of the FA. Piglets post-weaning having an immature intestine and not fully formed immune functions are very vulnerable to invading microorganisms. Manipulation of the milk FA composition via sow nutrition, or inclusion of dietary fat sources in the feed for newly weaned pigs, may be used as a strategic tool to enhance pig performance and their gut health and function pre- and post-weaning. Medium-chain fatty acids (MCFA) are absorbed directly into the portal blood and may contribute to immediate energy for the enterocytes. In addition, the MCFA, similarly to the short-chain fatty acids (SCFA), possess antibacterial effects and may thereby prevent overgrowth of pathogenic bacteria in the gastrointestinal tract. The essential FA, linoleic (LA) and α-linolenic (ALA) FA, form the building blocks for the long-chain polyunsaturated n-3 and n-6 FA. The conversion of ALA and LA into n-3 and n-6 eicosanoids, respectively, influences the molecular structures of metabolites and inflammatory reactions and other immune responses upon bacterial challenges. Dietary manipulation of the lactating sow influences the transfer of the n-3 and n-6 polyunsaturated fatty acids (PUFA) from the sow milk to the piglet and the incorporation of the FA into piglet enteric tissues and cell membranes, which exerts bioactivity of importance for immune responses and the epithelial barrier function. Especially, the n-3 PUFA present in fish oil seem to influence the gut health and function of pigs, and this is of importance during the transition periods such as post-weaning in which piglets are prone to inflammation. The proportion of unsaturated FA in the cell membranes influences the susceptibility to oxidative stress. Oxidative stress accompanies infectious diseases, and the development of lipid peroxides and other reactive oxygen products may be harmful to the epithelial barrier function. Fatty acid peroxides from the feed may also be absorbed with other lipid-solubles and thereby harm the intestinal function. Hence, antioxidative protection is important for the enteric cells. In conclusion, manipulation of the dietary FA composition can influence the gut health and function in pigs and may support a normal immune system and modulate resistance to infectious diseases during especially stressful phases of a pig's life such as post-weaning.
Topics: Animal Feed; Animals; Diet; Dietary Fats; Fatty Acids; Swine; Weaning
PubMed: 32215565
DOI: 10.1093/jas/skaa086 -
Nutrients Dec 2019Diet plays a key role in the maintenance and optimal functioning of immune cells. The Mediterranean dietary pattern is an example of a prudent choice of lifestyle and... (Review)
Review
Diet plays a key role in the maintenance and optimal functioning of immune cells. The Mediterranean dietary pattern is an example of a prudent choice of lifestyle and scientifically accepted to help preserve human health by protecting against major chronic and inflammatory diseases. Mediterranean diets (MedDiets) are characteristically high in the consumption of fruits, vegetables and salad, bread and whole grain cereals, potatoes, legumes/beans, nuts, and seeds. Their common central feature is the usage of olive oil as the main source of fat. The health benefits attributed to olive oil are specifically related to extra virgin olive oil (EVOO) intake with its high nutritional quality and multiple positive effects on health. Overall, MedDiets have direct (mono-unsaturated fatty acids (MUFAs), tocopherols, polyphenols) and indirect (low saturated fats, well-balanced linoleic/alpha linolenic acid) effects on the immune system and inflammatory responses. In the present paper, we summarize the current knowledge on the effect of olive oil per se and MedDiets generally on immune-mediated and inflammatory diseases, such as coronary heart disease (CHD)/cardiovascular diseases (CVD), obesity, type-2 diabetes, cancer, asthma, and allergies.
Topics: Cardiovascular Diseases; Diet, Mediterranean; Dietary Fats; Food; Humans; Immunomodulation; Olive Oil
PubMed: 31817038
DOI: 10.3390/nu11122941 -
Advances in Nutrition (Bethesda, Md.) Jul 2019
Topics: Diet; Dietary Fats; Female; Humans; Lipids; Male; Nutritional Status; Recommended Dietary Allowances; Risk Factors
PubMed: 31147674
DOI: 10.1093/advances/nmz052