Fat
Geoffrey P. Webb in Nutrition, 2019
Carbon atoms have the potential to each form four covalent bonds (i.e. they have a valency of four). In saturated fatty acids, all of the carbon atoms in the hydrocarbon chain are joined together by single bonds and all of the remaining valencies (bonds) of the carbon atoms are occupied by bonding to hydrogen atoms as shown in Figure 12.1b. These fatty acids are termed as saturated because all of the available bonds of the carbon atoms are occupied or “saturated” with hydrogen atoms. No more hydrogen atoms can be added to this hydrocarbon chain. The chemical structure of fatty acids is often represented schematically as shown in Figure 12.1c. Each angle represents a carbon atom and the carbon atoms in this book are numbered starting with the carbon furthest away from the carboxyl or acid group. The fatty acid depicted in this diagram is called palmitic acid, it has 16-carbon atoms and no double bonds and, therefore, it can be written in shorthand notation as 16:0.
Reasoning in clinical practice
R. Paul Thompson, Ross E.G. Upshur in Philosophy of Medicine, 2017
For some 50 years, the mantra that saturated fats increased the risk of cardiovascular disease was widely believed and widely propagated. Along the way there was controversy about his conclusions and his methodology but only in the last decade or so has the social consensus dissipated. Recent evidence suggests that the assumed causal links between diet and cholesterol, and between cholesterol and cardiovascular disease are significantly less clear than Keys claimed. The conclusion of a 2010 meta-analysis published in The American Journal of Clinical Nutrition was:A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat. (Siri-Tarino 2010)There are critics of this meta-study just as there were, and are, critics of Keys’ work. A concrete example of the dissolving consensus is the butter vs. margarine advice. For many decades, based on the medical claims of Keys and others, the public was advised to limited the intake of butter – a saturated fat – and favour margarine instead. Saturated fats increase “bad” (LDL) cholesterol and elevated levels of “bad” cholesterol increase significantly the risk of cardiovascular disease. Most margarine is a trans-fatty acid (commonly called trans fats). Margarine and shortening are made from oils that are liquid at ambient temperatures. They are rendered solid at those temperatures by partially hydrogenating them. The oils used in this process are mostly polyunsaturated (olive oil, by contrast, has a high proportion of monounsaturated fats). If a fatty acid molecule contains one double bond, it is monounsaturated; if it contains more than one double bond, it is polyunsaturated. Hydrogenation uses hydrogen to break a double bond between carbon atoms or carbon-based molecules. For example, oleic fatty acid is hydrogenated by the addition of H (two atoms of hydrogen). The result is on the right-hand side of Figure 9.1. The double bond on the left-hand side between the CH molecules is broken and two hydrogen atoms are added. A result of the process of hydrogenating a polyunsaturated fat is a trans fat; the configuration of the hydrogen bonds is changed.
The Importance of Personalized Nutrition in Psychological Disorders
Nilanjana Maulik in Personalized Nutrition as Medical Therapy for High-Risk Diseases, 2020
The numerous types of fatty acids are classified into three basic groups: saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids ( Mizunoya, Ohnuki et al. 2013). Animal products such as butter, cows’ milk, meat, salmon and egg yolks, and some plant products such as chocolate, cocoa butter, coconut and palm kernel oils are the main sources of saturated fatty acids (de Souza, Mente et al. 2015). According to a recent review analyzing the effect of SFA on dementia, a positive correlation between SFA intake and Alzheimer’s disease (AD) has been found in three of the four studies reviewed. In the fourth one, on the other hand, an inverse relationship was observed. SFA consumption was found to have a positive relationship with total dementia in one of two studies, with mild cognitive impairment in one of four studies and with cognitive decline in two of four studies (Barnard, Bunner et al. 2014). Previous studies have also detected correlations between MUFA/SFA changes and behavioral and cognitive results. Sartorius et al. (Sartorius, Ketterer et al. 2012) proposed that a high-SFA diet and acute intraventricular injection of palmitic acid in mice inhibited insulin signaling in the brain and locomotor activity in response to acute intraventricular injection of insulin. Similarly, normal wakefulness and sleep behavior were disrupted compared to a high-MUFA diet.
Dietary enrichment with alpha-linolenic acid during pregnancy attenuates insulin resistance in adult offspring in mice
Published in Archives Of Physiology And Biochemistry, 2014
K. S. Hollander, C. Tempel Brami, F. M. Konikoff, M. Fainaru, A. Leikin-Frenkel
Objective: Our objective was to test the contribution of dietary enrichment in essential or saturated fatty acids, in normocaloric diets, on the lipid accumulation and insulin resistance in the adult offspring in a C57Bl6/J mice model. Methods: Pregnant mothers were fed normocaloric diets containing 6% fat enriched in essential fatty acids (EFA): alpha-linolenic (ALA-18:3, n-3), linoleic (LA-18:2, n-6), or saturated fatty acids (SFA). After a washing-out period with regular diet, the offspring received a high-fat diet before euthanization. Results: Adult mice fed maternal ALA showed lower body weight gain and lower liver fat accumulation, lower HOMA index and lower stearoyl-CoA desaturase (SCD1) activity than those fed maternal SFA. Conclusion: The results observed using this novel model suggest that ALA in maternal diet may have the potential to inhibit insulin resistance in adult offspring.
Role of different dietary saturated fatty acids for cardiometabolic risk
Published in Clinical Lipidology, 2011
There is clinical and observational evidence to suggest that saturated fatty acids (SFA) increase cardiovascular disease risk compared with polyunsaturated fatty acids from vegetable oils. Replacing SFA intake has thus been a public health target, but the role of individual SFA in metabolic disease is still incompletely understood. Observational data indicate that all SFA may not necessarily be detrimental. The cholesterol-raising effect of SFA differs among individual SFA and possibly also with regard to cardiovascular and metabolic risk factors. The impact of dietary SFA on cardiovascular disease remains somewhat controversial, possibly due to such individual differences. In this article, we will also separately discuss the effects of dairy SFA, including biomarkers, as a means to elucidate these relationships between fatty acids, foodstuffs and cardiometabolic disease.
Individual saturated fatty acids are associated with different components of insulin resistance and glucose metabolism: the GOCADAN study
Published in International Journal of Circumpolar Health, 2010
Sven O.E. Ebbesson, M. Elizabeth Tejero, Juan Carlos López-Alvarenga, William S. Harris, Lars O.E. Ebbesson, Richard B. Devereux, Jean W. MacCluer, Charlotte Wenger, Sandra Laston, Richard R. Fabsitz, Barbara V. Howard, Anthony G. Comuzzle
Objectives. Type 2 diabetes and the consumption of saturated fatty acids (FAs) are on the rise among Alaska Inuits. This analysis, based on a cross-sectional study, explores the possible associations of saturated FA content in red blood cells (RBCs) and parameters of glucose metabolism in a sample of Alaska Natives. Study design and methods. The sample included 343 women and 282 men aged 35–74. Statistical analyses explored the associations of selected RBC (myristic, palmitic and stearic acids) FAs with fasting glucose (plasma), fasting insulin (plasma), 2h glucose (2-hour glucose tolerance test), 2h insulin and homeostasis model assessment (HOMA) index. The models included sex and glucose metabolism status as fixed factors and age, body mass index (BMI), waist circumference, physical activity (METS) and FA content in RBCs as covariates. Measures of insulin, glucose and HOMA index were used as dependent variables. Results. Myristic acid was positively associated with fasting insulin (β=0.47, p&0.001), 2h insulin (β=0.53, p=0.02) and HOMA index (β=0.455, p&0.001). Palmitic acid was associated with 2h glucose (β=2.3×10–2, p&0.001) and 2h insulin (β=5.6×10-2, p=0.002) and stearic acid was associated with fasting glucose (β=4.8×10-3, p=0.006). Conclusions. These results strongly support the hypothesis that saturated fatty acids are associated with insulin resistance and glucose intolerance and that saturated fatty acids are significant risk factors for type 2 diabetes.
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