Showing papers in "Lipids in 2007"
TL;DR: The purpose of this review is to outline the emerging role of dietary phytosterols in human health and to suggest that the retention of phyllosterols during food manufacturing and the use of foods with highphytosterol content may constitute an alternative to theUse of supplements.
Abstract: The purpose of this review is to outline the emerging role of dietary phytosterols in human health. Dietary saturated fat, cholesterol and fiber are currently emphasized in the reduction of low-density lipoprotein cholesterol levels. However, other dietary components such as phytosterols may have equivalent or even larger effects on circulating cholesterol and need further study with respect to the potential for coronary heart disease risk reduction. Phytosterol effects were not considered in classic fat-exchange clinical trials and may account for some of the differences attributed to the food fats studied. Phytosterols reduce cholesterol absorption while being poorly absorbed themselves and the effects can be studied in human subjects in single-meal tests using stable isotopic tracers. Because phytosterols are insoluble and biologically inactive when purified, careful attention needs to be given to ensuring that commercial supplement products are rendered bioavailable by dissolution in fat or by emulsification. Recent work shows that phytosterols in natural food matrices are also bioactive. The retention of phytosterols during food manufacturing and the use of foods with high phytosterol content may constitute an alternative to the use of supplements.
143 citations
TL;DR: There are multiple adverse effects of trans fatty acids that are produced by partial hydrogenation on CVD, blood lipids, inflammation, oxidative stress, endothelial health, body weight, insulin sensitivity, and cancer, and numerous agencies and governing bodies recommend limiting T FA in the diet and reducing TFA in the food supply.
Abstract: There are multiple adverse effects of trans fatty acids (TFA) that are produced by partial hydrogenation (i.e., manufactured TFA), on CVD, blood lipids, inflammation, oxidative stress, endothelial health, body weight, insulin sensitivity, and cancer. It is not yet clear how specific TFA isomers vary in their biological activity and mechanisms of action. There is evidence of health benefits on some of the endpoints that have been studied for some animal TFA isomers, such as conjugated linoleic acid; however, these are not a major TFA source in the diet. Future research will bring clarity to our understanding of the biological effects of the individual TFA isomers. At this point, it is not possible to plan diets that emphasize individual TFA from animal sources at levels that would be expected to have significant health effects. Due to the multiple adverse effects of manufactured TFA, numerous agencies and governing bodies recommend limiting TFA in the diet and reducing TFA in the food supply. These initiatives and regulations, along with potential TFA alternatives, are presented herein.
138 citations
TL;DR: It is suggested that leucine and nifedipine promote energy partitioning from adipocytes to muscle cells, resulting in decreased energy storage in adipocytes and increasing fatty acid utilization in muscle.
Abstract: Dietary calcium modulation of adiposity is mediated, in part, by suppression of calcitriol, while the additional effect of dairy products is mediated by additional components; these include the high concentration of leucine, a key factor in the regulation of muscle protein turnover. We investigated the effect of leucine, calcitriol and calcium on energy metabolism in murine adipocytes and muscle cells and on energy partitioning between adipocytes and skeletal muscle. Leucine induced a marked increase in fatty acid oxidation in C2C12 muscle cells (P < 0.001) and decreased FAS expression by 66% (P < 0.001) in 3T3-L1 adipocytes. Calcitriol decreased muscle cell fatty acid oxidation by 37% (P < 0.001) and increased adipocyte FAS gene expression by threefold (P < 0.05); these effects were partially reversed by either leucine or calcium channel antagonism with nifedipine. Co-culture of muscle cells with adipocytes or incubation with 48-h adipocyte conditioned medium decreased muscle fatty acid oxidation by 62% (P < 0.001), but treating adipocytes with leucine and/or nifedipine attenuated this effect. Leucine, nifedipine and calcitriol also modulated adiponectin production and thereby exerted additional indirect effects on fatty acid oxidation in C2C12 myotubes. Adiponectin increased IL-15 and IL-6 release by myotubes and partially reversed the inhibitory effects of calcitriol. Comparable effects of leucine, calcitriol and adiponectin were found in myotubes treated with conditioned medium derived from adipocytes or co-cultured with adipocytes. These data suggest that leucine and nifedipine promote energy partitioning from adipocytes to muscle cells, resulting in decreased energy storage in adipocytes and increasing fatty acid utilization in muscle.
131 citations
TL;DR: Dietary FO reverses dyslipidemia and improves insulin action and adiposity in the SRD fed rats, and reduces adipocytes cell size and thus, the smaller adipocytes are more insulin sensitive and the release of fatty acids decreases.
Abstract: Both genetic and environmental factors (e.g. nutrition, life style) contribute to the development of the plurimetabolic syndrome, which has a high prevalence in the world population. Dietary n-3 PUFAs specially those from marine oil (EPA and DHA) appear to play an important role against the adverse effects of this syndrome. The present work examined the effectiveness of fish oil (FO) in reversing or improving the dyslipidemia, insulin resistance and adiposity induced in rats by long-term feeding a sucrose-rich diet (SRD). We studied several metabolic and molecular mechanisms involved in both lipid and glucose metabolisms in different tissues (liver, skeletal muscle, fat pad) as well as insulin secretion patterns from perifused islets under the stimulation of different secretagogues. Dietary FO reverses dyslipidemia and improves insulin action and adiposity in the SRD fed rats. FO reduces adipocytes cell size and thus, the smaller adipocytes are more insulin sensitive and the release of fatty acids decreases. In muscle, FO normalizes both the oxidative and non-oxidative glucose pathways. Moreover, FO modifies the fatty acid composition of membrane phospholipids. In isolated β cells, lipid contents and glucose oxidation return to normal. All these effects could contribute to the normalization of glucose-stimulated insulin secretion and muscle insulin insensitivity.
130 citations
TL;DR: Recent work done in the field is reviewed, focusing on branch points and metabolic engineering to enhance and alter vitamin E content and composition in oilseed crops.
Abstract: Naturally occurring vitamin E, comprised of four forms each of tocopherols and tocotrienols, are synthesized solely by photosynthetic organisms and function primarily as antioxidants. These different forms vary in their biological availability and in their physiological and chemical activities. Tocopherols and tocotrienols play important roles in the oxidative stability of vegetable oils and in the nutritional quality of crop plants for human and livestock diets. The isolation of genes for nearly all the steps in tocopherol and tocotrienol biosynthesis has facilitated efforts to alter metabolic flux through these pathways in plant cells. Herein we review the recent work done in the field, focusing on branch points and metabolic engineering to enhance and alter vitamin E content and composition in oilseed crops.
128 citations
TL;DR: Two different algal oil capsule supplements and anAlgal oil-fortified food represent bioequivalent and safe sources of DHA.
Abstract: Docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, is important for eye and brain development and ongoing visual, cognitive, and cardiovascular health Unlike fish-sourced oils, the bioavailability of DHA from vegetarian-sourced (algal) oils has not been formally assessed We assessed bioequivalence of DHA oils in capsules from two different algal strains versus bioavailability from an algal-DHA-fortified food Our 28-day randomized, placebo-controlled, parallel group study compared bioavailability of (a) two different algal DHA oils in capsules ("DHASCO-T" and "DHASCO-S") at doses of 200, 600, and 1,000 mg DHA per day (n = 12 per group) and of (b) an algal-DHA-fortified food (n = 12) Bioequivalence was based on changes in plasma phospholipid and erythrocyte DHA levels Effects on arachidonic acid (ARA), docosapentaenoic acid-n-6 (DPAn-6), and eicosapentaenoic acid (EPA) were also determined Both DHASCO-T and DHASCO-S capsules produced equivalent DHA levels in plasma phospholipids and erythrocytes DHA response was dose-dependent and linear over the dose range, plasma phospholipid DHA increased by 117, 228 and 303 g per 100 g fatty acid at 200, 600, and 1,000 mg dose, respectively Snack bars fortified with DHASCO-S oil also delivered equivalent amounts of DHA on a DHA dose basis Adverse event monitoring revealed an excellent safety and tolerability profile Two different algal oil capsule supplements and an algal oil-fortified food represent bioequivalent and safe sources of DHA
125 citations
TL;DR: It is concluded that DHA supplemented during pregnancy plays a role in the maturation of the visual system.
Abstract: Within the visual system, docosahexaenoic acid (DHA, 22:6n−3) is an important structural component for retinal photoreceptors and cortical gray matter. There is a marked decrease in neural DHA accumulation in the face of DHA deficiency. DHA is accumulated at an accelerated rate during pregnancy, especially in the third trimester. However, pregnant women in the US and Canada have dietary DHA intakes that are significantly below the optimal level. The main objective of this study was to determine whether a DHA-functional food during pregnancy would benefit infant visual acuity at four and six months of age measured behaviorally using the acuity card procedure (ACP). In a randomized, longitudinal, double-blinded, and placebo-controlled trial, 30 pregnant women received either the DHA-functional food (n = 16) or the placebo (n = 14). There were significant main effects for visual acuity at four months of age (P = 0.018). The mean acuity scores were 3.8 ± 1.1 cycles/degree in the DHA group versus 3.2 ± 0.7 cycles/degree in the placebo group. At six months there were no group differences. Based on our results, we conclude that DHA supplemented during pregnancy plays a role in the maturation of the visual system.
116 citations
TL;DR: Observations suggest that MGS are a major source of the nonpolar lipids of the THE AUTHORS and Chl-E families for the tear film lipid layer (TFLL), but not of the previously reported phospholipid components of the TFLL.
Abstract: The purpose of the study was to qualitatively characterize the major lipid species present in human meibomian gland secretions (MGS) by means of high-performance liquid chromatography with atmospheric pressure ionization mass spectrometric detection of the analytes (NP HPLC-MS). Two different NP HPLC-MS methods have been developed to analyze lipid species that were expected to be present in MGS. The first method was optimized for the analysis of relatively nonpolar lipids [wax esters (WE), di- and triacyl glycerols (DAG and TAG), cholesterol (Chl) and its esters (Chl-E), and ceramides (Cer)], while the second method was designed to separate and detect phospholipids. The major lipid species in MGS were found to be WE, Chl-E, and TAG. A minor amount of free Chl (less then 0.5% of the Chl-E fraction) was detected in MGS. No appreciable amounts of DAG and Cer were found in MGS. The second NP HPLC-MS method, capable of analyzing model mixtures of authentic phospholipids (e.g. phosphatidylglycerol, phosphatidylethanolamine, phosphatidic acid, phosphatidylinositol, phosphatidylserine, phosphatidylcholine, and sphingomyelin) in submicrogram/mL concentrations, showed little or no presence of these species in the MGS samples. These observations suggest that MGS are a major source of the nonpolar lipids of the WE and Chl-E families for the tear film lipid layer (TFLL), but not of the previously reported phospholipid components of the TFLL.
98 citations
TL;DR: The evidence that patterns of LCPUFA exposure in pregnancy can influence aspects of fetal immune in ways that are consistent with the immunological properties of these nutrients in adults is summarised.
Abstract: This review explores the effects of dietary long chain polyunsaturated fatty acids (LCPUFA) on various aspects of early immune development and their potential role in the development or the prevention of immune disease. Modern diets have become increasingly rich in n-6 LCPUFA and relatively n-3 LCPUFA deficient. These potentially “pro-inflammatory” dietary changes have clear implications for the immature and developing fetal immune system. It is now well known that immunological abnormalities precede the development of allergic disease and are frequently evident at birth or in the first months of life. This has lead to the hypothesis that potential effects of LCPUFA could be greatest in very early life before immune responses and clinical phenotype are established. Here we summarise the evidence that patterns of LCPUFA exposure in pregnancy can influence aspects of fetal immune in ways that are consistent with the immunological properties of these nutrients in adults. Specifically, human studies have shown that higher levels of n-3 LCPUFA are associated with reduction in neonatal oxidative stress, reduced production of inflammatory leukotienne B4 (LTB4) and altered T cell function. Inverse correlations between n-3 LCPUFA levels and neonatal T cell cytokine production, are consistent with adult studies showing reduction in T cell cytokine production with fish oil supplementation. At this stage the relevance of these effects in the prevention of disease is unclear. Although there have been no effects of postnatal fish oil supplementation (from 6 months of age) on allergy prevention, preliminary studies suggest possible merits in pregnancy and there are ongoing pregnancy intervention studies to address this more definitively.
98 citations
TL;DR: Overall, the high forage diet of muskox seemed to produce a healthier fatty acid profile and highlighted the need to develop feeding strategies for intensively raising beef that will not negatively impacting fatty acid composition.
Abstract: Muskox (Ovibos moschatus) are ruminant animals native to the far north and little is known about their fatty acid composition. Subcutaneous adipose tissue (backfat) from 16 wild muskox was analyzed and compared to backfat from 16 barley fed beef cattle. Muskox backfat composition differed substantially from beef and the most striking difference was a high content of 18:0 (26.8 vs. 9.77%). This was accompanied by higher levels of most other saturated fatty acids except beef had more 16:0. Muskox backfat also had a lower level of cis-18:1 and this was related to a lower expression of steroyl-CoA desaturase mRNA. Beef backfat had a higher level of total trans-18:1 (4.25 vs. 2.67%). The most prominent trans-18:1 isomers in beef backfat were 10t-18:1 (2.13%) and 11t-18:1 (0.77%) whereas the most prominent isomers in muskox backfat were 11t-18:1 (1.41%), 13t/14t- (0.27%) and 16t-18:1 (0.23%). The total conjugated linoleic acid (CLA) content was higher in beef backfat than muskox (0.67 vs. 0.50%) with 9c,11t-18:2 as the most abundant CLA isomer. The second most abundant CLA isomer in beef backfat was 7t,9c-18:2 (0.10%) whereas in muskox it was 11t13c-18:2 (0.04%). Muskox backfat had a higher content of 18:3n-3 and its elongation and desaturation products 20:5n-3, 22:5n-3 and 22:6n-3 and a lower n-6/n-3 ratio. Overall, the high forage diet of muskox seemed to produce a healthier fatty acid profile and highlighted the need to develop feeding strategies for intensively raising beef that will not negatively impacting fatty acid composition.
97 citations
TL;DR: Combined low dose treatment of γ-tocotrienol with individual statins may have potential value in the treatment of breast cancer without causing myotoxicity that is associated with high dose statin treatment.
Abstract: Statins are potent inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase and display anticancer activity, but their clinical use is limited by their high-dose toxicity. Similarly, γ-tocotrienol, an isoform of vitamin E, also reduces HMGCoA reductase activity and displays potent anticancer activity. Studies were conducted to determine if combined low dose treatment of γ-tocotrienol with individual statins resulted in a synergistic antiproliferative effect on neoplastic mouse +SA mammary epithelial cells. Treatment with 3–4 μM γ-tocotrienol or 2–8 μM simvastatin, lovastatin or mevastatin alone resulted in a significant decrease, whereas treatment with 10–100 μM pravastatin had no effect on +SA cell growth. However, combined treatment of subeffective doses (0.25 or 10 μM) of individual statins with 0.25–2.0 μM γ-tocotrienol resulted in a dose-responsive synergistic inhibition in +SA cell proliferation. Additional studies showed that treatment with subeffective doses of individual statins or γ-tocotrienol alone had no effect, whereas combined treatment of these compounds resulted in a relatively large decrease in intracellular levels of phosphorylated (activated) MAPK, JNK, p38, and Akt. These findings strongly suggest that combined low dose treatment of γ-tocotrienol with individual statins may have potential value in the treatment of breast cancer without causing myotoxicity that is associated with high dose statin treatment.
TL;DR: It is noted that in the rat membrane fatty acid composition is a regulated parameter being more influenced by the balance between n-3 and n-6 polyunsaturates in the diet than it is by general diet content of saturated, monounsaturated and total polyunsaturated fats.
Abstract: The recent discovery that the fatty acid composition of tissue phospholipids varies in a systematic manner among species has lead to the proposal that membrane fatty acid composition is an important determinant of the metabolic rate characteristic for each species. Endotherms (mammals and birds) have a basal metabolic rate (BMR) that is several times that of ectotherms and have more polyunsaturated membranes. In both birds and mammals, as species size increases there is a decrease in mass-specific BMR and a decrease in membrane polyunsaturation. Membrane-associated processes are significant components of BMR and important membrane proteins operate at much faster rates in species with high BMR than in those with low BMR. A series of "species-crossover" experiments show that the rate of this molecular activity is largely due to the nature of the membrane bilayer surrounding these membrane proteins such that polyunsaturated membranes are associated with fast membrane-associated processes. It is suggested that this influence is due to the physical properties that such polyunsaturated membranes possess. This has been called the membrane pacemaker theory of metabolism and provides a framework to understand factors such as the influence of diet on metabolism. It is noted that in the rat membrane fatty acid composition is a regulated parameter being more influenced by the balance between n-3 and n-6 polyunsaturates in the diet than it is by general diet content of saturated, monounsaturated and total polyunsaturated fats.
TL;DR: In the 12-week rabbits, higher plasma triglycerides and apolipoprotein B levels shown in the standard and trans-10 18:1 groups compared with those in the trans-11 18: 1/CLA group are associated with higher plasma levels of very low density lipoproteins (VLDL) and lowdensity lipoprotein B shown in these two groups.
Abstract: The experiment was designed to study the effects of butters differing in conjugated linoleic acid (CLA) and trans 18:1 contents on lipoproteins associated with the risk of atherogenesis. New Zealand White male rabbits (9.6 weeks; 2.1 kg) were assigned for 6 or 12 weeks to three diets (n = 6 per diet) made of conventional pellets with 0.2% cholesterol and with 12% fat provided from a butter poor in trans-10 and trans-11 18:1 and in CLA (standard group), or rich in trans-10 18:1 (trans-10 18:1 group) or rich in trans-11 18:1 and in cis-9,trans-11 CLA (trans-11 18:1/CLA group). Blood samples were collected at the end of dietary treatments. Lipoproteins were separated by gradient-density ultracentrifugation. Lipid classes were determined enzymatically and apolipoproteins A-I and B by radial immunodiffusion. Mainly in the 12-week rabbits, higher plasma triglycerides and apolipoprotein B levels shown in the standard and trans-10 18:1 groups compared with those in the trans-11 18:1/CLA group are associated with higher plasma levels of very low density lipoproteins (VLDL) and low density lipoproteins (LDL) also shown in these two groups. In the 12-week rabbits, a shift towards denser LDL, considered as more atherogenic, was shown only in the trans-10 18:1 group. In these animals, the VLDL + LDL to HDL ratio was 1.7-2.3 times higher in the trans-10 18:1 group than in the other groups (P = 0.076). These results suggest a rather neutral effect of trans-11 18:1/CLA butter towards the risk of atherogenesis, whereas trans-10 18:1 butter would tend to be detrimental.
TL;DR: It is now possible to engineer common omega-6 rich oilseeds such as soybean and canola to produce EPA and DHA and this has been the focus of a number of academic and industrial research groups.
Abstract: Numerous clinical studies have demonstrated the cardiovascular and mental health benefits of including very long chain omega-3 polyunsaturated fatty acids, namely eicospentaenoic acid (EPA) and docosohexaenoic acid (DHA) in the human diet. Certain fish oils can be a rich source of omega-3 long chain polyunsaturated fatty acids although processed marine oils are generally undesirable as food ingredients because of the associated objectionable flavors and contaminants that are difficult and cost-prohibitive to remove. Oilseed plants rich in omega-3 fatty acids, such as flax and walnut oils, contain only the 18-carbon omega-3 polyunsaturated fatty acid alpha-linolenic acid, which is poorly converted by the human body to EPA and DHA. It is now possible to engineer common omega-6 rich oilseeds such as soybean and canola to produce EPA and DHA and this has been the focus of a number of academic and industrial research groups. Recent advances and future prospects in the production of EPA and DHA in oilseed crops are discussed here.
TL;DR: This paper describes for the first time a second SCD isoform in cattle, which appears to be an ortholog of human SCD5 rather than a homolog of bovine SCD1 or any of the described murineSCD isoforms.
Abstract: Stearoyl-CoA desaturase (SCD) is an enzyme responsible for the production of cis-9, trans-11 conjugated linoleic acid in ruminant fats, and for the synthesis of palmitoleoyl-CoA and oleoyl-CoA. To date, only one SCD isoform has been described in ruminant species, although multiple isoforms have been found in many other mammalian species. In this paper, we describe for the first time a second SCD isoform in cattle, which appears to be an ortholog of human SCD5 rather than a homolog of bovine SCD1 or any of the described murine SCD isoforms. As described in other SCD proteins, the predicted amino acid sequence of bovine SCD5 includes four transmembrane domains and three conserved histidine motifs. The amino-terminus of the predicted protein sequence of SCD5 lacks the PEST sequences typically found in SCD1 homologs, which are thought to target proteins for rapid degradation. Similar to human SCD5, the bovine SCD5 gene is organized into five exons and four introns, and is highly expressed in the brain. In other tissues examined, mRNA expression of SCD5 was minimal. Furthermore, the expression levels of SCD5 between brain gray and white matter are not different. This is the first description of a homolog of human SCD5 in a non-primate species.
TL;DR: A comparative study of linolenic acid and linseed oil kinetics revealed that the BH process was not significantly slowed by the esterification of polyunsaturated FAs, but may have been limited by the isomerization step in which the cis12 double bond goes to the trans11 position.
Abstract: The lipid quality of ruminant products is largely determined by the extent of rumen microbial biohydrogenation (BH) of polyunsaturated fatty acids (FAs) and the substances formed thereby. In vitro batch incubations with mixed rumen bacteria were tracked over 24 h to characterize the profiles and kinetics of the BH products from three lipid sources: pure linoleic acid (c9,c12-18:2), pure linolenic acid (c9,c12,c15-18:3) and linseed oil (mainly c9,c12,c15-18:3 in triacylglycerols). After 24 h of incubation biohydrogenation was more complete for c9,c12-18:2, which gave mainly stearic acid (18:0), than for c9,c12,c15-18:3, which yielded mainly trans-18:1 FAs. This suggests inhibition of the final BH step (18:1 to 18:0). Incubations of c9,c12-18:2 resulted in high levels of carbon 10- and 12-desaturated 18:1, t10,c12- and c9,t11-CLAs. Incubations of c9,c12,c15-18:3 resulted in high levels of t11-18:1, carbon 13- and 15-desaturated 18:1 as well as t11,c15-18:2 and 11,13-CLAs. A comparative study of linolenic acid and linseed oil kinetics revealed that the BH process was not significantly slowed by the esterification of polyunsaturated FAs, but may have been limited by the isomerization step in which the cis12 double bond goes to the trans11 position. The disappearance rates of c9,c12-18:2 and c9,c12,c15-18:3 ranged from 23.6 to 44.6%/h. The wide variety of BH intermediates found here underlines the large number of possible BH pathways. These data help provide a basis for dynamic approaches to BH processes.
TL;DR: The use of molecular genetics, molecular biology, and bioorganic chemical approaches on these mutants, as well as inhibitors of the MVA pathway, should help to understand plant sterol biosynthesis comprehensively.
Abstract: Sterols, which are biosynthesized via the cytoplasmic mevalonate (MVA) pathway, are important structural components of the plasma membrane and precursors of steroid hormones in both vertebrates and plants. Ergosterol and cholesterol are the major sterols in yeast and vertebrates, respectively. In contrast, plants produce a wide variety of phytosterols, which have various functions in plant development. Although the general biosynthetic pathway to plant sterols has been defined, the details of the biochemical, physiological, and developmental functions of genes involved in the biosynthetic network and their regulation are not well understood. Molecular genetic analyses are an effective approach to use when studying these fascinating problems. Since three enzymes, 3-hydroxy-3-methylglutaryl CoA reductase, farnesyl diphosphate synthase, and lanosterol synthase, have been functionally characterized in planta, we reviewed recent progress on these enzymes. Arabidopsis T-DNA and transposon insertion mutants are now widely available. The use of molecular genetics, molecular biology, and bioorganic chemical approaches on these mutants, as well as inhibitors of the MVA pathway, should help us to understand plant sterol biosynthesis comprehensively.
TL;DR: Health beneficial hypolipidemic and antioxidant influences of dietary spice principles—curcumin, capsaicin alone and in combination included in the diet for 8 weeks were evaluated in induced hypercholesterolemic rats to verify if there is any additive or synergistic effect of these two bioactive compounds.
Abstract: Health beneficial hypolipidemic and antioxidant influences of dietary spice principles--curcumin, capsaicin alone and in combination included in the diet for 8 weeks were evaluated in induced hypercholesterolemic rats, in order to verify if there is any additive or synergistic effect of these two bioactive compounds. Dietary curcumin (0.2%), capsaicin (0.015%) or their combination significantly countered the hypercholesterolemia brought about by high cholesterol feeding. Hepatic cholesterol was lowered by dietary spice principles only in normal rats. Liver triglyceride levels were lowered in both normal and hypercholesterolemic rats by capsaicin. Curcumin and capsaicin lowered hepatic and blood lipid peroxides in hypercholesterolemic rats, while the effect in blood was additive with their combination. Hepatic ascorbic acid was enhanced by dietary spice principles in normal rats; glutathione was enhanced by their combination only in hypercholesterolemic rats. Activities of serum glutathione reductase, glutathione transferase and catalase and hepatic glutathione reductase in normal rats and serum glutathione peroxidase in hypercholesterolemic rats were enhanced by dietary spice principles. While dietary curcumin and capsaicin normalized the changes in the levels of antioxidant molecules and activities of antioxidant enzymes to a significant extent, this effect was not generally additive when given in combination, and was higher than the individual effects only in a few instances.
TL;DR: The study suggests that tilapia (O. niloticus) has a limited capacity to synthesise 20:5 n-3 and 22:6n-3 from dietary 18:3n- 3, and the replacement of FO in the diet of farmed tilapio with vegetable oils could therefore lower tissue concentrations of 20: 5n-4 and 21:6 n-4, and consequently produce an aquaculture product of lower lipid nutritional value for the consumer.
Abstract: A 20-week feeding trial was conducted to determine whether increasing linolenic acid (18:3n-3) in vegetable oil (VO) based diets would lead to increased tissue deposition of 22:6n-3 in Nile tilapia (Oreochromis niloticus). Five isonitrogenous and isoenergetic diets were supplemented with 3% of either linseed oil (LO), a mixture of linseed oil with refined palm olein oil (PO) (LO-PO 2:1) and a mixture of refined palm olein oil with linseed oil (PO-LO 3:2) or with fish oil (FO) or corn oil (CO) as controls. The PO-LO, LO-PO and LO diets supplied a similar amount of 18:2n-6 (0.5% of diet by dry weight) and 0.5, 0.7 and 1.1% of 18:3n-3, respectively. Increased dietary 18:3n-3 caused commensurate increases in longer-chain n-3 PUFA and decreases in longer-chain n-6 PUFA in the muscle lipids of tilapia. However, the biosynthetic activities of fish fed the LO-based diets were not sufficient to raise the tissue concentrations of 20:5n-3, 22:5n-3 and 22:6n-3 to those of fish fed FO. The study suggests that tilapia (O. niloticus) has a limited capacity to synthesise 20:5n-3 and 22:6n-3 from dietary 18:3n-3. The replacement of FO in the diet of farmed tilapia with vegetable oils could therefore lower tissue concentrations of 20:5n-3 and 22:6n-3, and consequently produce an aquaculture product of lower lipid nutritional value for the consumer.
TL;DR: This paper introduces a further development of the whole-body fatty acid balance method for the estimation of the elongation and desaturation of fatty acids, and spells out in detail the theoretical basis and the methods of application.
Abstract: Currently there are several contrasting methods utilized for estimating elongation and desaturation of fatty acids and their general metabolism. The majority of these methods involve an ex vivo approach, requiring expensive and sophisticated equipment, likely to result in considerable variation in enzyme activity between and within species. In the present paper we introduce a further development of the whole-body fatty acid balance method for the estimation of the elongation and desaturation of fatty acids. This method though receiving considerable attention because of its simplicity and reliability has yet to be presented in detail. Theoretically, the whole-body fatty acid balance method can potentially be applied to any organism and requires little more than a gas chromatography unit for fatty acid analysis and elementary calculations. As such in this paper we attempt to spell out in detail the theoretical basis and the methods of application drawing specific examples. Using the present method it is possible to measure the fate of individual fatty acids towards desaturation, elongation and oxidation and calculate the elongase, Δ-6 desaturase and Δ-5 desaturase activities.
TL;DR: In this review, the most useful and practical methods for the isolation and analysis of CLA isomers in tissues and in commercial CLA preparations are described.
Abstract: Natural and synthetic conjugated linoleic acids (CLA) are reputed to have therapeutic properties that are specific to particular geometrical and positional isomers. Analysis of these has presented unique problems that have brought forward distinctive solutions, especially the use of gas chromatography-mass spectrometry and silver-ion high-performance liquid chromatography. In the analysis of CLA present at low levels in tissue samples, it is sometimes necessary to use concentration methods. In this review, the most useful and practical methods for the isolation and analysis of CLA isomers in tissues and in commercial CLA preparations are described.
TL;DR: It is demonstrated, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake.
Abstract: Macadamia nuts are rich source of monounsaturated fats (oleic and palmitoleic acids) and contain polyphenol compounds, therefore, their consumption can be expected to impart health benefits to humans. This study was conducted to examine the effects of consuming macadamia nuts in hypercholesterolemic male individuals on plasma biomarkers of oxidative stress, coagulation and inflammation. Seventeen hypercholesterolemic male subjects were given macadamia nuts (40–90 g/day), equivalent to 15% energy intake, for a period of 4 weeks. As expected, monounsaturated fatty acids (16:1n-7, 18:1n-9 and 20:1n-9) were elevated in the plasma lipids of all volunteers following intervention with macadamia nuts. Plasma markers of inflammation (leukotriene, LTB4) and oxidative stress (8-isoprostane) were significantly lower (1,353 ± 225 vs. 1,030 ± 129 pg/mL and 876 ± 97 vs. 679 ± 116 pg/mL, respectively) within 4 weeks following macadamia nut intervention. There was a non-significant (23.6%) reduction in the plasma TXB2/PGI2 ratio following macadamia nut consumption. This study demonstrates, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake. These data, combined with our previous results on cholesterol-lowering effects of macadamia nuts, suggest that regular consumption of macadamia nuts may play a role in the prevention of coronary artery disease.
TL;DR: Interestingly, the developing olive fruit was found to accumulate significant amounts of parkeol as an ester conjugate, indicating a redirection of the carbon flux from the triterpenoid pathway towards the sterol pathway.
Abstract: Drupes were handpicked from olive (Olea europaea L.) trees, cv chemlali, at 13 distinct stages of fruit development, referred to as weeks after flowering (WAF), and analyzed for their free and esterified sterols and triterpenoids content. These two classes of compounds are synthesized via the acetate/mevalonate pathway and share common precursors up to oxidosqualene (OS). Cyclization of OS in either cycloartenol or β-amyrin constitutes a branch point between primary (sterol pathway) and secondary (triterpenoid pathway) metabolisms. At the onset of fruit development, i.e., between 12 and 18 WAF, drupes were found to contain high amounts of α- and β-amyrins as well as more-oxygenated compounds such as triterpenic diols (erythrodiol and uvaol) and acids (oleanolic, ursolic and maslinic acids). Concomitantly, sterol precursors were barely detectable. From 21 WAF, when the olive fruit reached its final size and began to turn from green to purple, α- and β-amyrins were no longer present, while 4,4-dimethyl- and 4α-methylsterols started to be formed, indicating a redirection of the carbon flux from the triterpenoid pathway towards the sterol pathway. Between 21 and 30 WAF, sterol end products, mainly represented by sitosterol, progressively accumulated and triterpenic diols were replaced by triterpenic acids, essentially maslinic acid. Interestingly, the developing olive fruit was found to accumulate significant amounts of parkeol as an ester conjugate. Whatever the stage of development, triterpenoids represent the major triterpenic compounds of the olive fruit.
TL;DR: SDA supplementation increased the EPA content of RBC and heart and may have utility as a plant-based source of omega-3 FA, compared to dietary EPA, which was 20–23% as efficient in raising tissue EPA levels.
Abstract: Plant sources of omega-3 fatty acids (FA) are needed that can materially raise tissue levels of long-chain omega-3 FA [i.e., eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 20:6n-3)]. Stearidonic acid (SDA; 18:4n-3) is the delta-6 desaturase product of alpha-linolenic acid (ALA; 18:3n-3), and when fed to humans, increases red blood cell (RBC) content of EPA to a greater extent than does ALA. This study was undertaken to determine the dose-dependence and time course of the increase in the EPA and DHA content of the heart and RBC in dogs. Adult male Beagles were fed 21, 64, or 193 mg/kg of SDA in in their food daily for up to 12 weeks. Positive and negative controls were given EPA (43 mg/kg) or high oleic acid sunflower oil, respectively. The baseline EPA content of RBC was 0.38 +/- 0.03% which increased (P<0.01) in a dose-dependent manner, with the high dose of SDA and EPA achieving levels of 1.33 +/- 0.26 and 1.55. +/- 0.28%, respectively. In the heart, the content of EPA rose from 0.06 +/- 0.01 to 1.24 +/- 0.22% in the EPA group and to 0.81 +/- 0.32% in the high SDA group (both P<0.01). In both tissues, DHA did not change. Compared to dietary EPA, SDA was 20-23% as efficient in raising tissue EPA levels. In conclusion, SDA supplementation increased the EPA content of RBC and heart and may have utility as a plant-based source of omega-3 FA.
TL;DR: A novel ESR approach was developed, which facilitates the investigation of the reaction stoichiometry of antioxidants towards stable radicals, and the influence of the hydrophobic properties of the antioxidant was clearly seen in Brij micelles.
Abstract: To characterize parameters influencing the antioxidant activity at interfaces a novel ESR approach was developed, which facilitates the investigation of the reaction stoichiometry of antioxidants towards stable radicals. To relate the activity of antioxidants towards the location of radicals at interfaces NMR experiments were conducted. Micellar solutions of SDS, Brij and CTAB were used to model interfaces of different chemical nature. The hydrophilic Fremy's radical was found to be solubilized exclusively in the aqueous phase of SDS micellar solution but partitioned partly into the hydrophilic headgroup area of Brij micelles. In contrast the hydrophobic galvinoxyl was exclusively located in the micellar phase with the increasing depth of intercalation in the order SDS < Brij < CTAB. Gallates revealed a higher stoichiometric factor towards galvinoxyl in CTAB systems, which is accounted to a concentration effect of antioxidant and radical being both solubilized in the palisade layer. In contrast, in SDS solutions hardly any reaction between galvinoxyl and gallates was found. SDS acted as a physical barrier between radical (palisade layer) and antioxidant (stern layer). The influence of the hydrophobic properties of the antioxidant was clearly seen in Brij micelles. Elongation of the alkyl chain in gallate molecule resulted in increasing stoichiometric factors in the presence of galvinoxyl being located in the deeper region of the bulky headgroup area. The reverse trend was found in the presence of Fremy's radical being located in the hydrated area of the micelles.
TL;DR: It is demonstrated that DHA-rich fish oil supplementation (2.16 g DHA/day) can improve plasma lipids in a dose-dependent manner in patients taking statins and these changes were achieved by 3 months.
Abstract: The objective of the study was to evaluate potential benefits of docosahexaenoic acid (DHA) rich fish oil supplementation as an adjunct to statin therapy for hyperlipidaemia. A total of 45 hyperlipidaemic patients on stable statin therapy with persistent elevation of plasma triglycerides (averaging 2.2 mmol/L) were randomised to take 4 g/day (n = 15) or 8 g/day (n = 15) of tuna oil or olive oil (placebo, n = 15) for 6 months. Plasma lipids, blood pressure and arterial compliance were assessed initially and after 3 and 6 months in 40 subjects who completed the trial. Plasma triglycerides were reduced 27% by 8 g/day DHA-rich fish oil (P < 0.05) but not by 4 g/day when compared with the placebo and this reduction was achieved by 3 months and was sustained at 6 months. Even though total cholesterol was already well controlled by the statin treatment (mean initial level 4.5 mmol/L), there was a further dose-dependent reduction with fish oil supplementation (r = -0.344, P < 0.05). The extent of total cholesterol reduction correlated (r = -0.44) with the initial total cholesterol levels (P < 0.005). In the subset with initial plasma cholesterol above 3.8 mmol/L, plasma very low density lipoprotein (VLDL), intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL) were isolated and assayed for cholesterol and apolipoprotein B (apoB) at the commencement of the trial and at 3 months of intervention. Fish oil tended to lower cholesterol and apoB in VLDL and raise both in LDL. There were no changes in IDL cholesterol, IDL apoB and high-density lipoprotein cholesterol. The results demonstrate that DHA-rich fish oil supplementation (2.16 g DHA/day) can improve plasma lipids in a dose-dependent manner in patients taking statins and these changes were achieved by 3 months. Fish oil in addition to statin therapy may be preferable to drug combinations for the treatment of combined hyperlipidaemia.
TL;DR: In this paper, the authors analyzed expression profiles of 12 castor genes involved in fatty acid and TAG synthesis using quantitative reverse transcription-polymerase chain reaction technology using a collection of castor seeds with well-defined developmental stages and morphologies was used to determine the levels of mRNA, ricinoleate and TAG.
Abstract: Castor seed triacylglycerols (TAGs) contain 90% ricinoleate (12-hydroxy-oleate) which has numerous industrial applications Due to the presence of the toxin ricin and potent allergenic 2S albumins in the seed, it is desirable to produce ricinoleate from temperate oilseeds To identify regulatory genes or genes for enzymes that may up-regulate multiple activities or entire pathways leading to the ricinoleate and TAG synthesis, we have analyzed expression profiles of 12 castor genes involved in fatty acid and TAG synthesis using quantitative reverse transcription-polymerase chain reaction technology A collection of castor seeds with well-defined developmental stages and morphologies was used to determine the levels of mRNA, ricinoleate and TAG The synthesis of ricinoleate and TAG occurred when seeds progressed to stages of cellular endosperm development Concomitantly, most of the genes increased their expression levels, but showed various temporal expression patterns and different maximum inductions ranging from 4- to 43,000-fold Clustering analysis of the expression data indicated five gene groups with distinct temporal patterns We identified genes involved in fatty acid biosynthesis and transport that fell into two related clusters with moderate flat-rise or concave-rise patterns, and others that were highly expressed during seed development that displayed either linear-rise or bell-shaped patterns Castor diacylglycerol acyltransferase 1 was the only gene having a higher expression level in leaf and a declining pattern during cellular endosperm development The relationships among gene expression, cellular endosperm development and ricinoleate/TAG accumulation are discussed
TL;DR: Asperamides A and B were characterized from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from marine brown alga Colpomenia sinuosa, and displayed moderate activity against Candida albicans.
Abstract: Asperamides A (1) and B (2), a sphingolipid and their corresponding glycosphingolipid possessing a hitherto unreported 9-methyl-C-20-sphingosine moiety, were characterized from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from marine brown alga Colpomenia sinuosa. The structures were elucidated by spectroscopic and chemical methods as (2S,2'R,3R,3'E,4E,8E)-N-(2'-hydroxy-3'-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (1) and 1-O-beta-D-glucopyranosyl-(2S,2'R,3R,3'E,4E,8E)-N-(2'-hydroxy-3'-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (2). In the antifungal assay, asperamide A (1) displayed moderate activity against Candida albicans.
TL;DR: Results show that, despite no effect on plasma cholesterol, the GTE upregulated the LDL receptor in vivo, which appears to be via a reduction in liver cholesterol concentration and suggests that the green tea extract was able to increase the efflux of cholesterol from liver cells.
Abstract: Green tea extracts have hypocholesterolaemic properties in epidemiological and animal intervention studies. Upregulation of the low-density lipoprotein (LDL) receptor may be one mechanism to explain this as it is the main way cholesterol is removed from the circulation. This study aimed to determine if a green tea extract could upregulate the hepatic LDL receptor in vivo in the rat. A green tea extract (GTE) enriched in its anti-oxidant constituents, the catechins, was fed to rats (n = 6) at concentrations of either 0, 0.5, 1.0 or 2.0% (w/w) mixed in with their normal chow along with 0.25% (w/w) cholesterol for 12 days. Administration of the GTE had no effect on plasma total or LDL cholesterol concentrations but high-density lipoprotein significantly increased (41%; p < 0.05). Interestingly, there was a significant increase in LDL receptor binding activity (2.7-fold) and LDL receptor protein (3.4-fold) in the 2% (w/w) treatment group compared to controls. There were also significant reductions in liver total and unesterified cholesterol (40%). Administration of the GTE significantly reduced cholesterol absorption (24%) but did not affect cholesterol synthesis. These results show that, despite no effect on plasma cholesterol, the GTE upregulated the LDL receptor in vivo. This appears to be via a reduction in liver cholesterol concentration and suggests that the green tea extract was able to increase the efflux of cholesterol from liver cells.
TL;DR: Virgin olive oil reduced oxidative stress and modulated the inducible isoform of nitric oxide synthase, diminishing platelet aggregation and protecting the brain from the effects of hypoxia–reoxygenation.
Abstract: We investigated how virgin olive oil (VOO) affected platelet and hypoxic brain damage in rats. Rats were given VOO orally for 30 days at 0.25 or 0.5 mL kg(-1) per day (doses A and B, respectively). Platelet aggregation, thromboxane B2, 6-keto-PGF(1alpha), and nitrites + nitrates were measured, and hypoxic damage was evaluated in a hypoxia-reoxygenation assay with fresh brain slices. Oxidative stress, prostaglandin E2, nitric oxide pathway activity and lactate dehydrogenase (LDH) activity were also measured. Dose A inhibited platelet aggregation by 36% and thromboxane B2 by 19%; inhibition by dose B was 47 and 23%, respectively. Virgin olive oil inhibited the reoxygenation-induced increase in lipid peroxidation (57% in control rats vs. 2.5% (P < 0.05) in treated rats), and reduced the decrease in glutathione concentration from 67 to 24% (dose A) and 41% (dose B). Brain prostaglandin E2 after reoxygenation was 306% higher in control animals, but the increases in treated rats were only 53% (dose A) and 45% (dose B). The increases in nitric oxide production (213% in controls) and activity of the inducible isoform of nitric oxide synthase (175% in controls) were both smaller in animals given VOO (dose A 84%; dose B 12%). Lactate dehydrogenase activity was reduced by 17% (dose A) and 42% (dose B). In conclusion, VOO modified processes related to thrombogenesis and brain ischemia. It reduced oxidative stress and modulated the inducible isoform of nitric oxide synthase, diminishing platelet aggregation and protecting the brain from the effects of hypoxia-reoxygenation.