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1.
The plasma cholesterol level is influenced by the quality and the quantity of the dietary fat. In regard to vegetable fat one has to distinguish between the opposing effects of saturated fatty acids and polyunsaturated fatty acids. If the normal diet, which contains predominantly saturated fatty acids is changed to a diet rich in polyunsaturated fatty acids one can observe a fall in plasma cholesterol. This phenomenon has been confirmed by many observers. A satisfactory explanation for the lipidlowering properties of polyunsaturated fats has not been found so far. Three theories are discussed: a. increase of cholesterol and bile acid excretion in the feces. b. decrease of the capacity of lipoproteins to carry lipids. c. redistribution of cholesterol with transport of plasma cholesterol to the tissues.  相似文献   

2.
Cobalamin deficiency represents a health issue for vegetarians, especially vegans, if supplements are not consumed. Vitamin B12 serum levels, traditionally used to assess the vitamin B12 status, can be normal under functional deficiency conditions. In this regard, methylmalonic acid (MMA) has proven to be a more specific marker to detect subclinical vitamin B12 deficiency. In this study, we present for the first time the cobalamin status of Spanish vegetarians using both vitamin B12 and MMA markers, and the effects of the plant-based diet and the intake of vitamin B12 supplements. Healthy adults were recruited (n?=?103, 52% vegans). Dietary preferences and use of supplements were assessed by questionnaires and serum samples were collected and stored. Vitamin B12 was measured by chemiluminiscence and MMA by liquid chromatography tandem mass spectrometry (LC-MS/MS) using solid phase extraction for sample preparation. Obtained values, median (IQR), were: vitamin B12, 278.9 (160.2) pmol/l and MMA, 140.2 (78.9) nmol/l. No significant differences between lacto-ovo vegetarians and vegans were observed. Considering these two markers, 10% of the participants were mild vitamin B12 deficient. Supplementation (75% of the participants) was associated with higher vitamin B12 (p?<?0.001) and lower MMA (p?=?0.012). In conclusion, Spanish vegetarians have low risk of vitamin B12 deficiency due to vitamin B12 supplementation and the MMA determination is useful to detect mild deficiency.  相似文献   

3.
Acidogenic diets, commonly measured by the potential renal acid load (PRAL), have been linked with metabolic diseases including insulin resistance, hepatic dysfunction, and cardiometabolic risk. Vegan diets are linked to low dietary acid loads, but the degree of adherence to a vegan diet to demonstrate this benefit is unknown. This study compared the change in PRAL and urine pH of omnivores who followed a vegan diet for either 2, 3, or 7 days over one week. Healthy adults were recruited from a campus population and randomly assigned to one of the three groups: VEG7 (vegan diet followed for seven consecutive days); VEG3 (vegan diet followed for three evenly spaced days over one week); or VEG2 (vegan diet followed for two evenly spaced days over one week). Gender, age, and body mass index did not differ between groups (overall: 21.8 ± 2.4 y and 24.4 ± 5.6 kg/m2). Following the one week intervention, outcome measures did not vary between the VEG2 and VEG3 groups, and these groups were collapsed for the final analyses. The 24-h urine pH was raised after seven consistent days of vegan diet adherence and was unchanged after 2–3 days of vegan diet adherence over the course of a week (+0.52 ± 0.69 and ?0.02 ± 0.56 respectively, p = 0.048). However, dietary PRAL scores fell significantly in both dietary groups during the 7-day trial. Since low dietary PRAL scores have been related to improve metabolic parameters, adoption of a vegan diets for several days per week should be explored as a diet strategy to lower disease risk.  相似文献   

4.
This study was undertaken to assess the effect of blended oils, i.e., polyunsaturated fatty acid (PUFA) rich vegetable oils like safflower oil (SFO) and sunflower oil (SNO) with the unconventional and hypocholesterolemic rice bran oil (RBO) on the serum lipid profile of rats. Rats fed RBO + SNO/SFO at 70:30 ratio for a period of 28 days showed significantly (p < 0.05) lower levels of total cholesterol (TC), triglycerides (TG) and low density lipoprotein (LDL) cholesterol and increased high density lipoprotein (HDL) cholesterol in animals fed a high cholesterol diet (HCD) and cholesterol free diet (CFD). Liver total cholesterol (TC) and triglycerides (TG) were also reduced. Fecal excretion of neutral sterols and bile acids was increased with use of RBO blends. RBO, which is rich in tocopherols and tocotrienols, may improve the oxidative stability of the blends. Tocotrienols are known to inhibit 3-hydroxy, 3-methyl, glutaryl CoA (HMG-COA) reductase (rate limiting enzyme in cholesterol biosynthesis), resulting in hypocholesterolemia. In addition to improving the lipid profile by lowering TC, TG and LDL-C and increasing HDL-C, blending of RBO with other oils can result in an economic advantage of lower prices.  相似文献   

5.
The aim of this study was to investigate possible blood glucose-lowering effects of plant extracts in vivo for which prior to this a peroxisome proliferator-activated receptor-γ activity in vitro was observed. The ability of extracts of winter savory, purple coneflower, buckwheat and black elder to dose-dependently activate peroxisome proliferator-activated receptor-γ was determined in a reporter gene assay in COS-1 cells. For evaluation of glucose-lowering effects in vivo, db/db mice were fed a diet containing either rosiglitazone (0.02 g/kg diet, positive control) or one of the plant extracts (0.1 and 1 g/kg diet) for four weeks. Apart from glucose, insulin, triacylglycerols, non-esterified fatty acids, cholesterol and adiponectin were determined in plasma. All plant extracts showed a dose-dependent peroxisome proliferator-activated receptor-γ-activating effect in vitro. In db/db mice none of the plant extracts exerted glucose-lowering effects at the used dosages compared to rosiglitazone. Non-esterified fatty acids, triacylglycerols, cholesterol, insulin and adiponectin in plasma were not altered by the plant extracts as well. Although dose-dependent peroxisome proliferator-activated receptor-γ activity could be shown in COS-1 cells, the experiments in db/db mice lacked to confirm any anti-diabetic effect of the plant extracts in vivo and emphasizes the importance of verifying cell culture data using an appropriate in vivo model.  相似文献   

6.
Previous research has demonstrated that the total replacement of corn oil (CO) with cottonseed oil (CSO) in the diets of growing male rats results in a lowering of the total cholesterol (TC) concentration in the serum. It is not, however, known if a partial replacement of dietary CO with CSO would be sufficient to lower TC levels, nor is the effect of replacing dietary CO with CSO on other indices of cholesterol status (e.g., the levels of high-density lipoprotein cholesterol [HDL-C], non-HDL-C [i.e., very-low and low-density lipoprotein-cholesterol], or the TC/HDL-C ratio). Growing male rats were fed diets having CO, CSO, or a CO/CSO (1:1, w/w) oil mixture (OM) as the source of dietary oil (diet groups CO, CSO, and OM, respectively). There were no differences between CO and OM groups for TC, HDL-C, non-HDL-C, or the TC/HDL-C ratio. However, TC was significantly lower (p 0.05)for the CSO group than the CO group (2.85 vs. 3.23 mmol/l, or 110 vs. 125 mg/dl, respectively) as was HDL-C (1.83 vs. 2.13 mmol/l, or 71 vs. 82 mg/dl, respectively), but there were no differences between these groups for non-HDL-C or the TC/HDL-C ratio. Diet had no effect on serum triglycerides (TGs) or on total liver content of either cholesterol or TGs. Thus, partial (50%) replacement of CO with CSO was without effect on any of these serum indices of cholesterol status, but total replacement resulted in lower TC and HDL-C, without affecting non-HDL-C or the TC/HDL-C ratio. Because, relative to CO, CSO has higher levels of saturated fatty acids but lower levels of monounsaturated and polyunsaturated fatty acids, the cholesterol-lowering effect of CSO appears to be unrelated to its fatty acid composition, and may be caused by a component of its nonsaponifiable fraction.  相似文献   

7.
Fatty acids are important compounds for insects, but the requirements for essential fatty acids may differ between insect species. Most of the fatty acids are acquired through the insect’s diet; therefore, supplementing the diet with baker’s yeast (Saccharomyces cerevisiae Meyen ex E.C. Hansen), which produces unsaturated fatty acids, was predicted to affect the fatty acid composition of the insect. The tested insect was the black soldier fly (BSF) (Hermetia illucens L.), that is used as a source of protein and fat in feed. Therefore, there is importance for BSF larvae (BSFL) nutritional composition, especially the unsaturated fatty acids content, which is one of the nutritional limitations for mammalian diets. The dominant fatty acids of the tested BSFL were the saturated fatty acids: lauric, myristic, and palmitic acids, as found in other BSF studies. Oleic acid (c18:1) and linoleic acid (C18:2) were the abundant unsaturated fatty acids in the BSFL. The proportion of linoleic acid was higher in the substrate with the supplemental yeast; however, this did not affect its proportion in the larvae. The higher proportion of linoleic acid may have been exploited as a source for production of saturated lauric acid. Therefore, providing unsaturated fatty acids to the substrate through supplemental baker’s yeast is not the most efficient way to increase the proportion of unsaturated fatty acids in the larvae.  相似文献   

8.
The aim of this work was to identify and quantify fatty acids presented in pollen samples collected from six different Serbian maize hybrids by GC capillary method. Due to great importance of fatty acids as food component potential nutritional value of maize pollen as food supplement in human diet was determined. It has been shown that pollen is a great source of different fatty acids, especially unsaturated fatty acids. In total, twenty eight fatty acids were quantify - the most abundant saturated FAs were palmitic and henicosanoic acid; the most prevalent monounsaturated FAs were oleic, elaidic and cis-10-heptadecenoic acid. Linoleic and cis-11,14-eicosadienoic acid were the most abundant polyunsaturated fatty acid. Also, it was found that FAs composition was significantly influenced by the type of maize hybrids. According to nutritional recommendations, four of six pollen samples had good nutritional quality with unsaturated/saturated fatty acids ratio higher than 1.6, but there is unsatisfied distribution of ω-6 and ω-3 fatty acids as the most important type of unsaturated fatty acids.  相似文献   

9.
To clarify the functional properties of potato pulp (PP), a waste product resulting from extraction of starch from potatoes, we examined the effects of PP on cholesterol metabolism and cecal conditions in rats. Plasma total cholesterol (T-Chol) levels were lower in rats fed a PP-supplemented diet for four weeks than in those fed a control diet. Cecal pH was lowered due to an increase in the levels of cecal total short-chain fatty acids, especially butyrate, in the PP group compared to the control group. Furthermore, animals fed with the PP-supplemented diet showed increased cecal ratios of Lactobacillus and Clostridia and decreased cecal ratios of Bacteroides and Gammaproteobacteria with slightly negative and positive correlations with plasma T-Chol levels, respectively. In conclusion, ingestion of PP for four weeks is likely to improve both cecal conditions and cholesterol metabolism, suggesting that PP has prebiotic effects.  相似文献   

10.
Florisil固相萃取法联用气相色谱测定油脂中sn-2位脂肪酸   总被引:1,自引:0,他引:1  
为探寻与气相色谱分析相配套的高效前处理方法,以测定不同物种来源的油脂中sn-2位(β位)脂肪酸组成及含量,考察了Florisil固相萃取柱对经sn-1,3专一性脂肪酶水解后的油脂各产物的分离富集能力,并对萃取条件进行了优化。结果表明,Florisil固相萃取柱能有效地将sn-2单甘脂从油脂水解产物中分离;同时发现Florisil固相萃取可以实现油脂水解产物中甘油三酯、甘油二酯、单甘脂及游离脂肪酸的依次分离。5种不同来源的油脂(植物油、藻油、微生物油脂、鱼油和海豹油脂),水解后经Florisil固相萃取柱萃取,联用气相色谱测定sn-2位脂肪酸组成及含量,结果表明,植物油、藻油和海豹油中sn-2位主要为中长链不饱和脂肪酸(植物油sn-2位中C18∶1,C18∶2和C18∶3约占95%;藻油sn-2位中C16∶1,C18∶1和C18∶2约占50%;海豹油sn-2位中C16∶1,C18∶1和C18∶2约占67%),菌油和鱼油中sn-2位多为长链多不饱和脂肪酸(菌油sn-2位中C20∶4约占37%;鱼油sn-2位中C20∶5,C22∶5和C22∶6约占40%)。  相似文献   

11.
There have been few studies on the effect of cottonseed oil (CSO), one of the most commonly used vegetable oils in the United States, on indices of lipid status either in the rat or in any other species. Previous studies with rats have focused on the effect of CSO, versus that of other vegetable oils, on the concentration of cholesterol in serum and liver or on a limited number of fatty acids in serum, adipose tissue, or liver. The present study was designed to compare more fully than in previous studies the effect of CSO to that of corn oil (CO) on the fatty acid composition of serum, adipose tissue, and liver. Two groups of male rats (n=10 each) were used, each fed one of two purified diets containing 100 g/kg of either CO or CSO. Between-group differences included higher values (mol% total fatty acids) in adipose tissue for palmitic acid and stearic acid, but lower values in serum, adipose tissue, and liver for cis-vaccenic acid and oleic acid (C18:1n-9) for the CSO group than the CO. In addition, values in serum, adipose tissue, and liver for -linolenic acid (C18:3n-3) and its metabolite, docosahexaenoic acid (C22:6n-3), were lower for the CSO group than the CO. There was no effect of diet on serum or tissue levels of n-6 fatty acids (linoleic acid, dihomo--linolenic acid, and arachidonic acid). Differences in fatty acid compositions noted, e.g., those for C18:1n-9 and C22:6n-3, mainly reflected compositional differences between the two oils. Thus, use of CSO rather than CO affected serum and tissue concentrations of saturated, monounsaturated, and n-3 polyunsaturated fatty acids (PUFAs) but had no effect on n-6 PUFA status.  相似文献   

12.
选用两组转基因品质改良大豆(富含硫氨基酸)为材料,利用磷脂脂肪酸(PLFA)法分析了在大田种植条件下,两组转基因大豆对土壤微生物群落结构的影响。结果表明,与非转基因大豆相比,转基因品种土壤微生物群落的结构发生明显的变化。在两组转基因品种中PLFA组分均发生变化,其中转基因品种A组中占主导地位的14种分别是是革兰氏阳性菌(GP)的特征脂肪酸16:0、10Me18:0和好氧细菌特征脂肪酸18:1ω7c,B组中占主导地位的13种是表征GP的脂肪酸15:0、16:0和非特征脂肪酸14Me16:0。在A组的OE-8品种及B组的17-4和57品种中,表征细菌的PLFA含量和总PLFA含量与非转基因品种相比有显著上升。结果表明种植转基因大豆影响根际土壤微生物群落结构。  相似文献   

13.
The production of polyunsaturated fatty acids (PUFA) in Tisochrysis lutea was studied using the gradual incorporation of a 13C-enriched isotopic marker, 13CO2, for 24 h during the exponential growth of the algae. The 13C enrichment of eleven fatty acids was followed to understand the synthetic pathways the most likely to form the essential polyunsaturated fatty acids 20:5n-3 (EPA) and 22:6n-3 (DHA) in T. lutea. The fatty acids 16:0, 18:1n-9 + 18:3n-3, 18:2n-6, and 22:5n-6 were the most enriched in 13C. On the contrary, 18:4n-3 and 18:5n-3 were the least enriched in 13C after long chain polyunsaturated fatty acids such as 20:5n-3 or 22:5n-3. The algae appeared to use different routes in parallel to form its polyunsaturated fatty acids. The use of the PKS pathway was hypothesized for polyunsaturated fatty acids with n-6 configuration (such as 22:5n-6) but might also exist for n-3 PUFA (especially 20:5n-3). With regard to the conventional n-3 PUFA pathway, Δ6 desaturation of 18:3n-3 appeared to be the most limiting step for T. lutea, “stopping” at the synthesis of 18:4n-3 and 18:5n-3. These two fatty acids were hypothesized to not undergo any further reaction of elongation and desaturation after being formed and were therefore considered “end-products”. To circumvent this limiting synthetic route, Tisochrysis lutea seemed to have developed an alternative route via Δ8 desaturation to produce longer chain fatty acids such as 20:5n-3 and 22:5n-3. 22:6n-3 presented a lower enrichment and appeared to be produced by a combination of different pathways: the conventional n-3 PUFA pathway by desaturation of 22:5n-3, the alternative route of ω-3 desaturase using 22:5n-6 as precursor, and possibly the PKS pathway. In this study, PKS synthesis looked particularly effective for producing long chain polyunsaturated fatty acids. The rate of enrichment of these compounds hypothetically synthesized by PKS is remarkably fast, making undetectable the 13C incorporation into their precursors. Finally, we identified a protein cluster gathering PKS sequences of proteins that are hypothesized allowing n-3 PUFA synthesis.  相似文献   

14.
The essential oil and fatty acid composition of two provenances of Ruta chalepensis from four organs (leaves, flowers, stems and fruits) was determined. The effect of the plant part on total fatty acid contents, essential oil yields, fatty acid and volatile constituents was significant.Fatty acid profiles varied significantly among the studied provenances and organs. Linolenic acid had the highest amount in leaves of the two provenances. From R. chalepensis, in all organs, the main fatty acids were palmitic (13.10-25.31%), followed by palmitoleic (0-15.72%), stearic (1.03-6.85%), oleic (1.90-24.04%), arachidic (0.11-4.03%), eicosatetraenoic (0.10-5.60%) and behenic (0.47-6.09%) acids. Saturated fatty acids had the highest amounts in growing wild R. chalepensis flowers, and cultivated R. chalepensis stems were characterized by the predominance of polyunsaturated fatty acids. Oil composition of all studied organs has a healthy and nutritionally value. Essential oil yields varied from 0.39% to 2.46% and showed a remarkable variation with plant organs. Thirty-six volatile compounds were identified in different analyzed essential oils; 2-undecanone, 2-nonanol and 2-dodecanone had the highest percentages.  相似文献   

15.
The hypocholesterolemic effect of dietary proteins could not be related to their vegetal or animal origin and seemed correlated to their different amino acids proportions. Comparing rats fed soy protein diet to those fed casein diet for 45 days, we observed a decrease of serum HDL cholesterol levels. Furthermore sequential centrifugation showed a decrease of HDL2–3 fraction and especially apolipoprotein E in the serum of soy protein fed rats. The sodium phytate, added to the diet, did not change the metabolism of sterols.  相似文献   

16.
Microalgae have been emerging as an important source for the production of bioactive compounds. Marine diatoms can store high amounts of lipid and grow quite quickly. However, the genetic and biochemical characteristics of fatty acid biosynthesis in diatoms remain unclear. Glycerophospholipids are integral as structural and functional components of cellular membranes, as well as precursors of various lipid mediators. In addition, diacylglycerol acyltransferase (DGAT) is a key enzyme that catalyzes the last step of triacylglyceride (TAG) biosynthesis. However, a comprehensive sequence-structure and functional analysis of DGAT in diatoms is lacking. In this study, an isoform of diacylglycerol acyltransferase type 2 of the marine diatom Phaeodactylum tricornutum was characterized. Surprisingly, DGAT2 overexpression in P. tricornutum stimulated more oil bodies, and the neutral lipid content increased by 35%. The fatty acid composition showed a significant increase in the proportion of polyunsaturated fatty acids; in particular, EPA was increased by 76.2%. Moreover, the growth rate of transgenic microalgae remained similar, thereby maintaining a high biomass. Our results suggest that increased DGAT2 expression could alter fatty acid profile in the diatom, and the results thus represent a valuable strategy for polyunsaturated fatty acid production by genetic manipulation.  相似文献   

17.
茶儿茶素对鱼油的抗氧化活性   总被引:12,自引:1,他引:12  
研究了添加茶儿茶素对鱼油中多烯脂肪酸(DHA、EPA)分解和过氧化物形成的抑制效果。结果表明,茶儿茶素可有效地抑制鱼油的过氧化物形成和多烯脂肪酸分解,在相同的温度(30℃)条件下,茶儿茶素的抗氧化活性优于维生素E  相似文献   

18.
脂肪酸是乌龙茶香气形成的关键前体。选择18个茶树品种的闽北乌龙茶(毛茶与其复焙茶)和3个茶树品种的闽南清香型乌龙茶,采用硫酸-甲醇法制备脂肪酸甲酯,运用气相色谱-质谱分析其脂肪酸的组成及含量。结果表明,福建乌龙茶中检测到11种脂肪酸,含量较高的主要是含16个和18个碳原子的脂肪酸;闽北乌龙茶的脂肪酸总量及不饱和度均低于闽南乌龙茶;十六碳酸(C16:0)、顺,顺-9,12-十八碳二烯酸(C18:2)和顺,顺-9,12,15-十八碳三烯酸(C18:3)等9种脂肪酸的含量在品种间差异显著,以雀舌的C18:3和多不饱和脂肪酸含量最高;复焙对闽北乌龙茶的脂肪酸的影响与其碳原子数和不饱和度有关,其中二十二碳酸(C22:0)和二十四碳酸(C24:0)全部降解,但含量下降最多的脂肪酸是C18:3。由此可见,福建乌龙茶的脂肪酸含量及组成差异特征与其产地有关,并受茶树品种和工艺的影响。  相似文献   

19.
Omega-3 polyunsaturated fatty acids are associated with a lower risk of cardiometabolic diseases. However, docosahexaenoic acid (DHA) is easily oxidized, leading to cellular damage. The present study examined the effects of an increased concentration of DHA in fish oil (80% of total fatty acids) on cardiometabolic risk factors and oxidative stress compared to coconut oil, soybean oil, and fish oil containing eicosapentaenoic acid (EPA) and DHA in a balanced ratio. Forty healthy male Sprague–Dawley rats were supplemented with corresponding oil for 10 weeks. Supplementation with the fish oil containing 80% DHA decreased plasma fat, plasma total cholesterol and muscle fat compared to the coconut oil and the soybean oil. Increasing concentrations of DHA induced incorporation of DHA and EPA in cell membranes and tissues along with a decrease in ω-6 arachidonic acid. The increase in DHA promoted lipid peroxidation, protein carbonylation and antioxidant response. Taken together, the increased concentration of DHA in fish oil reduced fat accumulation compared to the coconut oil and the soybean oil. This benefit was accompanied by high lipid peroxidation and subsequent protein carbonylation in plasma and in liver. In our healthy framework, the slightly higher carbonylation found after receiving fish oil containing 80% DHA might be a protecting mechanism, which fit with the general improvement of antioxidant defense observed in those rats.  相似文献   

20.
Kenaf (Hibiscus cannabinus L.) is a fibre plant native to east-central Africa. The potential for using kenaf seeds as a source of edible oil is often overlooked when considering kenaf as a fibre and feed crop. The aim of this research was to study and compare the fatty acid composition and oil content of eight commercial kenaf varieties from various countries. Linoleic, oleic, and palmitic acid were the predominant fatty acids in all cultivars. Percentages of fatty acids varied greatly among different kenaf varieties. Gregg had the highest percentage of linoleic acid whilst El Salvador had the lowest. El Salvador had the highest percentage of oleic acid and Endora had the highest percentage of palmitic acid. Stearic acid and palmitic acid were positively correlated, as well as stearic and linoleic acid. Increasing stearic and linolenic acid and reducing palmitic acid at the same time therefore might be difficult through conventional breeding. The oil content was 19.84% on average and there was not much difference between the varieties. The relatively high oil content and the unique fatty acid composition, suggested that kenaf seed could be used as a source of edible oil. Kenaf oil can be considered nutritionally healthy because of the relatively high amount of monounsaturated and polyunsaturated fatty acids.  相似文献   

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