Article

Mechanisms by which Dietary Fatty Acids Modulate Plasma Lipids1

Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA.
Journal of Nutrition (Impact Factor: 4.23). 10/2005; 135(9):2075-8.
Source: PubMed

ABSTRACT Dietary fatty acids have a considerable effect on plasma LDL cholesterol (LDL-C) concentrations and therefore on the risk for coronary heart disease. Numerous studies have been conducted in animal models to elucidate the mechanisms by which different types of fatty acids modulate plasma cholesterol concentrations. In addition, multiple clinical trials and epidemiological data have demonstrated the effects of fatty acids in determining the concentrations of circulating LDL. SFAs and trans fatty acids have a detrimental effect on plasma lipids, whereas PUFAs of the (n-6) family and monounsaturated fatty acids decrease plasma LDL-C concentrations. Among the SFAs, stearic acid (18:0) appears to have a neutral effect on LDL-C, while lauric (12:0), myristic (14:0), and palmitic (16:0) acids are considered to be hypercholesterolemic. SFAs increase plasma LDL-C by increasing the formation of LDL in the plasma compartment and by decreasing LDL turnover. Although unsaturated fatty acids increase cholesterol synthesis, they also increase hepatic LDL receptor number and LDL turnover in vivo. Fatty acids are also ligands of important regulatory elements, which can play a role in determining plasma cholesterol. This article presents a summary of the major effects of various types of fatty acids on plasma lipid concentrations and the mechanisms involved.

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    • "Our analyses showed that although it contained similar amounts of total lipid and protein to the wild-caught diet, the latter was enriched in unsaturated fatty acid content. The commercial diet contained more myristic acid, but this saturated fatty acid is not regarded as providing nutritional benefit: it raises circulating cholesterol and decreases low-density lipoprotein (LDL) receptor activity, whereas the unsaturated fatty acids have the opposite effects (Fernandez and West 2005). Because dietary enrichment with polyunsaturated fatty acids leads to corresponding enrichment of the egg yolk content in seahorses (Saavedra et al. 2014), the two treatments would have resulted in major differences in egg provisioning. "
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    ABSTRACT: The aim of the present study was to investigate the hypothesis that parental periconception nutrition in adult seahorses affects the development and growth of their offspring. We tested the hypothesis that because seahorse embryos develop inside the male's brood pouch, manipulation of the male's diet would affect offspring growth and development independently of the female's diet. Adult males and females were fed separately with either wild-caught crustaceans or commercial aquarium diet for 1 month before conception to influence the periconception environment. Approximately 10000 offspring were obtained from four different treatment groups (Male/Wild or Male/Commercial×Female/Wild or Female/Commercial). Weights, physical dimensions and fatty acid profiles of the newborns were determined. Offspring produced when the males receiving commercial diet were mated with wild-fed females were larger (P<0.05) than those produced by wild-fed males. When both males and females were fed with commercial diet, their offspring were significantly smaller than those from the other treatment groups. When commercial diet-fed females were mated with wild-fed males, the offspring showed distortion of the snout:head length ratio. These results support the view that the preconception diet received by males and females differentially affects embryonic development.
    Reproduction Fertility and Development 12/2014; DOI:10.1071/RD14169 · 2.58 Impact Factor
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    • "Our analyses showed that although it contained similar amounts of total lipid and protein to the wild-caught diet, the latter was enriched in unsaturated fatty acid content. The commercial diet contained more myristic acid, but this saturated fatty acid is not regarded as providing nutritional benefit: it raises circulating cholesterol and decreases low-density lipoprotein (LDL) receptor activity, whereas the unsaturated fatty acids have the opposite effects (Fernandez and West 2005). Because dietary enrichment with polyunsaturated fatty acids leads to corresponding enrichment of the egg yolk content in seahorses (Saavedra et al. 2014), the two treatments would have resulted in major differences in egg provisioning. "
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    ABSTRACT: As in mammals, seahorse embryos develop internally but, unlike in mammals, this process occurs within a paternal structure (the brood pouch). Functionally, the brood pouch supports developing embryos through placenta-like interactions, but as egg quality is determined by the female's diet, the seahorse system offers opportunities to study the effect of the male's diet on embryo development while varying the female's diet independently. In this study, we investigated the hypothesis that development of seahorse embryos is affected differentially by independent manipulation of the male and female parental diets. Adult males and females were fed separately with either wild-caught crustaceans (Male-W or Female-W, respectively) or commercial aquarium diet (Male-C or Female-C, respectively) for 1 month before conception and during the subsequent pregnancy (approximately 15 days). Dietary unsaturated fatty acid content (18:3n-3) and (20:4n-6) in the W diet was approximately double that in the C diet. In total, 5231 first-brood offspring were obtained from 4 treatment groups formed from (1) Male-W×Female-W; (2) Male-C×Female-W; (3) Male-W×Female-C; and (4) Male-C×Female-C. Each treatment was replicated with 4 couples. Newborns (10 from each brood) were weighed and dimensions measured. Fifteen-day postnatal survival rates were determined from 40 offspring/couple (N at Day 0=160/treatment) and fatty acid profiles were evaluated. Data were analysed by nested analyses of covariance (ANCOVA); replicates were nested within treatments and individual offspring measurements were nested within replicates (male and female parental sizes were used as covariates). Offspring produced by the Male-C×Female-W were ~10% taller (both as standard length and tail length; P<0.05) than those produced by Male-W×Female-W couples but their 15-day survival was poorer (12.9% v. 39%; χ(2)=39.19, 1 DF; P<0.001). Fifteen-day survival of the other groups was 0% in both cases. When both male and female parents were fed the commercial diet, their offspring were considerably smaller than those from all the other treatments (P<0.05). The offspring produced by Male-W×Female-C couples showed distortion of the snout:head length ratio, a phenotypic feature that was highly consistent in the Male-W×Female-W treatment group. Fatty acid profiles of the offspring showed significant dependence on the preconception dietary treatment; 20:4n-6 and 22:6n-3 contents were significantly lower in Male-C×Female-C than in Male-W×Female-C (P<0.01) offspring, showing that the male's pouch could compensate for the poorer quality of lipids derived directly from eggs. These results support the hypothesis that diet received during the preconception period and pregnancy by the males and females differentially affects embryonic growth and fatty acid content, and suggest that seahorses are a suitable model species for understanding the effects of parental diet on offspring health.
    Reproduction Fertility and Development 12/2014; 27(1):153. DOI:10.1071/RDv27n1Ab122 · 2.58 Impact Factor
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    • "Short-chain (4–8 carbon) SFAs and medium-chain decanoic fatty acid (C10:0), as well as long-chain stearic acid (C18:0), do not increase the risk of CHD. In contrast, lauric (C12:0), myristic (C14:0) and palmitic (C16:0) acids can raise LDL-cholesterol (LDL-c) concentrations , mainly by decreasing LDL receptor activity (Fernandez & West, 2005). Monounsaturated fatty acids (MUFAs) and nÀ6 and nÀ3 polyunsaturated fatty acids (PUFAs) can decrease LDL-c by different mechanisms (Bays, Tighe, Sadovsky, & Davidson, 2008; Moreno & Mitjavila, 2003). "
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    ABSTRACT: Chitosan, a deacetylated form of chitin, is a dietary fibre known for its hypolipidemic properties, which are mainly attributed to its unique cationic characteristics. We studied the selective in vivo effect of chitosan on fat excretion in order to elucidate its hypolipidemic mechanism. A 4-week longitudinal study was conducted in guinea pigs and the effect of chitosan on fat-absorption was compared to that of a soluble fibre: digestion-resistant maltodextrin. Animals were fed with high-fat isocaloric diets containing 12/100g of cellulose, digestion-resistant maltodextrin or chitosan. Subsequently, the excretion of fatty acids, neutral sterols and bile acids was determined. Chitosan selectively reduced fat absorption in comparison to digestion-resistant maltodextrin. The excretion of lauric, myristic and palmitic fatty acids of animals fed with chitosan was more than 10-, 5- and 2-fold higher, respectively, than in the cellulose group, whereas stearic acid excretion was not significantly altered. Oleic, linoleic and α-linolenic acid excretion were also significantly higher (P<0.001). The n-6/n-3 ratio in faeces of the chitosan group was 23.68, compared to 13.95 in the cellulose group. Total neutral sterol excretion was increased by both dietary fibres, whereas bile acid excretion was only increased by chitosan. Nevertheless, chitosan inhibited the intestinal bioconversion of cholesterol and primary bile acids to secondary metabolites. Hence, these results reveal that chitosan and digestion resistant maltodextrin exert their hypolipidemic activity by different mechanisms.
    Food Chemistry 09/2012; 134(2):940-7. DOI:10.1016/j.foodchem.2012.02.211 · 3.26 Impact Factor
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