Effects of palm oil on cardiovascular risk.

A major public health concern of affluent nations is the excessive consumption of dietary fats which are now closely linked to coronary heart disease. Against this scenario, the tropical oils and palm oil in particular, have been cast as major villains in the U.S.A., despite the fact that palm oil consumption there is negligible. The unsuspecting public may not realise that the call to avoid palm oil is nothing more than a trade ploy since in recent years palm oil has been very competitive and has gained a major share of the world's edible oils and fats market. Many also lose sight of the fact that, palm oil, like other edible oils and fats, is an important component of the diet. The allegation that palm oil consumption leads to raised blood cholesterol levels and is therefore atherogenic is without scientific foundation. Examination of the chemical and fatty acid composition of palm oil or its liquid fraction should convince most nutritionists that the oil has little cholesterol-raising potential. The rationale for these are: it is considered cholesterol free. its major saturated fatty acid, palmitic acid (16:0) has recently been shown to be neutral in its cholesterolaemic effect, particularly in situations where the LDL receptors have not been down-regulated by dietary means or through a genetic effect. palm oil contains negligible amounts (less than 1.5%) of the hypercholesterolemic saturated fatty acids, namely lauric acid (12:0) and myristic acid (14:0). it has moderately rich amounts of the hypocholesterolaemic, monounsaturated oleic acid (18:1, omega-9) and adequate amounts of linoleic acid. (18:2, omega-6). It contains minor components such as the vitamin E tocotrienols which are not only powerful antioxidants but are also natural inhibitors of cholesterol synthesis. Feeding experiments in various animal species and humans also do not support the allegation that palm oil is atherogenic. On the contrary, palm oil consumption reduces blood cholesterol in comparison with the traditional sources of saturated fats such as coconut oil, dairy and animal fats. In addition, palm oil consumption may raise HDL levels and reduce platelet aggregability. As with all nutrients, there is a need to obtain a balance of different fatty acids found in fats in edible oils and other food sources. There is no single ideal source of fat that answers to the recent American Heart Association's call to reflect a 1:1:1 ratio of saturated, monounsaturated and polyunsaturated fats in relation to the recommended dietary fat intake of 30% of calories or less.(ABSTRACT TRUNCATED AT 400 WORDS)     

不同类型脂肪酸对SD大鼠血清脂肪酸及胰岛素抵抗的影响

目的分析中链饱和脂肪酸(MC-SFA,MCF组)、长链饱和脂肪酸(LC-SFA,LCF组)、n-6多不饱和脂肪酸(n-6 PUFA,SUF组)和n-3多不饱和脂肪酸(n-3 PUFA,TUF组)四种脂肪酸对大鼠血清脂肪酸及胰岛素抵抗的影响。方法雄性SD大鼠40只随机分为5组,对照组给予普通日粮,高脂组给予脂肪热量比相同的高脂日粮。喂养10周,每18 d测定空腹血糖(GLU)、血清脂肪酸、血清胰岛素水平,根据胰岛素敏感性指数(ISI)=ln1/(FPG×FINS)评定大鼠的胰岛素敏感性。结果10周后,LCF组和SUF组大鼠体重显著高于对照组和其它高脂组;LCF组血清胰岛素显著高于对照组(P﹤0.05);LCF组、TUF组ISI显著低于对照组(P﹤0.05);各组间血糖无明显差异(P0.05)。SUF组、TUF组血清LC-SFA浓度显著低于LCF组(P﹤0.05);TUF组血清(n-3 PUFA)显著高于对照组和其它高脂组(P﹤0.05)。结论不同类型脂肪酸的高脂饲料对SD大鼠的血清脂肪酸组成和含量有显著的影响,SD大鼠脂肪沉积及胰岛素抵抗程度随血清脂肪酸代谢作用的不同而变化。     

Dietary fatty acids and coronary heart disease

Epidemiological studies have confirmed a strong association between fat intake, especially saturated and trans fatty acids, plasma cholesterol levels and rate of coronary heart disease (CHD) mortality. Meanwhile it is clear, that early atherosclerosis is largely preventable by modifying nutritional behaviour and lifestyle. There is clear evidence that a diet moderate in total fat (25-35 % energy) is superior to extremes in dietary fat. Because fat is energy dense moderation in fat intake is also essential for weight control. Saturated fatty acids are very potent in increasing LDL-cholesterol concentration in plasma a dangerous risk factor for early CHD. Unsaturated fatty acids have numerous beneficial health effects. The results of prospective cohort studies fit well to the experimental experience of the antihypercholesterolemic action of Omega-6 fatty acids and the antithrombotic, vasodilatory and antiarrhythmic properties of Omega-3 fatty acids, while the optimistic rating of Omega-9 fatty acids is less supported by epidemiologic studies. The results of prospective cohort studies are confirmed by intervention trials revealing that saturated fatty acids enhance early development of CHD whereas polyunsaturated fatty acids, especially of the Omega-3 type, significantly preserve from CHD. In context with a prudent diet pattern favourable dietary fatty acid composition offers the best chance for a reduced risk of CHD.     

Coconut fats

In many areas of Sri Lanka the coconut tree and its products have for centuries been an integral part of life, and it has come to be called the "Tree of life". However, in the last few decades, the relationship between coconut fats and health has been the subject of much debate and misinformation. Coconut fats account for 80% of the fat intake among Sri Lankans. Around 92% of these fats are saturated fats. This has lead to the belief that coconut fats are 'bad for health', particularly in relation to ischaemic heart disease. Yet most of the saturated fats in coconut are medium chain fatty acids whose properties and metabolism are different to those of animal origin. Medium chain fatty acids do not undergo degradation and re-esterification processes and are directly used in the body to produce energy. They are not as 'bad for health' as saturated fats. There is the need to clarify issues relating to intake of coconut fats and health, more particularly for populations that still depend on coconut fats for much of their fat intake. This paper describes the metabolism of coconut fats and its potential benefits, and attempts to highlight its benefits to remove certain misconceptions regarding its use.     

Changes in the fatty acid composition and hydroxyproline content in rat lung in relation to collagen synthesis after paraquat administration

OBJECTIVES: Effect of paraquat on the fatty acid composition (weight percentage) of rat lung was studied with particular reference to the change of hydroxyproline content in the course of paraquat-induced dysfunction and subsequent repair. METHODS: Eight-week-old male Wistar rats were administered paraquat at 20 mg/kg body weight subcutaneously, and the wet weight, hydroxyproline content and fatty acid composition of lungs of each group rats were analyzed at 2, 7, 14 or 28 days after treatment, respectively. RESULTS: The percentage of palmitic acid (C16:0), arachidonic acid (C20:4) and docosahexaenoic acid (C22:6) significantly increased, and the percentage of oleic acid (C18:1) and the ratio of monounsaturated fatty acids/saturated fatty acids (M/S) significantly decreased comparing to control on day 28 after paraquat administration. The time-course of each fatty acid was observed for 28 days after paraquat administration. M/S ratio decreased after paraquat administration up to the 28th day, but the polyunsaturated fatty acids/saturated fatty acids (P/S) ratio decreased during the first 7 days, followed by a increase, and then reached higher level than the 0 day control at the 28th day. Hydroxyproline also increased between the 14th and the 28th days. Eicosapentaenoic acid (C20:5) had once increased during the first 2 days and decreased gradually, while C20:4 maintained high level in this period. C22:6 increased after paraquat administration and maintained high level up to the 28th day. This result indicated that desaturation and elongation in n-3 series fatty acids were accelerated after paraquat treatment, and consequently C20:5 was rapidly converted into C22:6 and decreased. CONCLUSIONS: Paraquat might cause elevation of unsaturated fatty acids, espe- cially C20:4 but not C20:5 by the stimulation of the fatty acid desaturase system, and could consequently stimulate local collagen synthesis by C20:4 metabolites in the healing stage.     

玫瑰茄花萼中脂肪酸成分的GC-MS分析

目的:采用气相色谱-质谱联用技术(GC-MS)对玫瑰茄花萼中提取的油脂进行脂肪酸组成分析。方法:采用索氏提取法提取玫瑰茄花萼中的油脂,甲酯化后运用GC-MS联用技术进行分离和结构鉴定。结果:玫瑰茄花萼油脂中含有17种脂肪酸,其中主要的脂肪酸为亚油酸(45.03%)、油酸(23.62%)、棕榈酸(22.91%)、硬脂酸(3.41%)、(10E)-10-十九烯酸(1.91%)、棕榈油酸(0.84%)、花生酸(0.53%)和肉豆蔻酸(0.34%)。其中不饱和脂肪酸含量高达71.40%以上。结论:玫瑰茄油脂中富含不饱和脂肪酸,具有较高的营养价值和保健功能。     

大叶福王草的脂溶性化学成分

目的 研究大叶福王草的脂溶性化学成分。方法 溶剂萃取法提取脂溶性成分，采用气相色谱-质谱-计算机联用技术，结合标准谱库，对大叶福王草脂溶性成分进行分析鉴定。结果 共鉴定出22个化合物，占脂溶性总成分74，84％，主要为萜类和脂肪酸类化合物，亚油酸含量占14．73％。结论 大叶福王草脂溶性化学成分中主要为脂肪酸及其酯类化合物，亚油酸含量最高。     

Serum cholesterol predictive equations in product development

The aim of the study was to incorporate trans fatty acids into predictive equations for serum cholesterol and compare their effects with the effects of the individual saturated fatty acids 12:0, 14:0 and 16:0. We have introduced trans fatty acids from partially hydrogenated soybean oil (TransV) and fish oil (TransF) into previously published equations by constrained regression analysis. Prior knowledge about the signs and ordering of existing regression coefficients were incorporated into the regression modelling by adding lower and upper bounds to the coefficients. Oleic acid (18:1) and polyunsaturated fatty acids (18:2, 18:3) were not sufficiently varied in the studies and the respective regression coefficients therefore set equal to those found by Yu et al. (Am J Clin Nutr 1995;61:1129-39). Stearic acid (18:0) considered to be neutral was not included in the equations. The regression analyses were based on results from four controlled dietary studies with a total of 95 participants and including 10 diets differing in fatty acid composition. The analyses resulted in the following equations where the change in cholesterol is expressed in mmol/L and the change in intake of fatty acids is expressed in E%: Delta Total cholesterol = 0.01 delta(12:0) + 0.12 Delta(14:0) + 0.057 delta(16:0) + 0.039 delta(TransF) + 0.031 delta(TransV)- 0.0044 delta(18:1) - 0.017 delta(18:2, 18:3) and deltaLDL cholesterol = 0.01 delta(12:0) + 0.071 delta(14:0) + 0.047 delta(16:0) + 0.043 delta(TransF) + 0.025 delta(TransV) - 0.0044 delta(18:1) - 0.017 delta(18:2, 18:3). The test set used for validation consisted of 22 data points from seven recently published dietary studies. The equation for total cholesterol showed good prediction ability with a correlation coefficient of 0.981 between observed and predicted values. The equation has been used to reformulate margarines into "trans free" products all with more favourable effects on serum cholesterol than previous products. Also a cholesterol reducing margarine has been produced. When tested against butter in an open clinical trial among subjects with mild hypercholesterolemia the observed cholesterol-lowering effect of this margarine corresponded reasonably well with the predicted (0.77 vs. 0.64 mmol/L). We conclude that the equation has practical applicability and can be used to formulate and nutritionally optimise fat products as well as to evaluate already existing products on the market.     

Changing concepts in lipid nutrition in health and disease

Fat remains a hot topic because of concerns over associations between consumption of fats and the incidence of some chronic conditions including coronary artery disease, diabetes, cancer and obesity. Dietary fats serve multiple purposes. The effects of dietary fats generally reflect the collective influences of multiple fatty acids in the diet or food. This presentation highlights some recent developments on the role of dietary fats and oils in health and disease. Debate continues over the role of dietary modification in coronary prevention by lipid lowering. The degree to which a recommended diet will result in health benefits for an individual is difficult to predict, because the outcome will depend on the influence of other factors such as a person's genetic constitution, level of physical activity and total diet composition. There can now be little doubt about the importance of genetic factors in the etiology of cardiovascular disease, diabetes, obesity and cancer. The importance of antioxidant status in the prevention of cardiovascular disease as well as many cancers is being increasingly recognised. It is now evident that not all saturated fatty acids are equally cholesterolemic. Recent accounts evaluating palm oil's effects on blood lipids and lipoproteins suggest that diets incorporating palm oil as the major dietary fat do not raise plasma total and LDL cholesterol levels to the extent expected from its fatty acid composition. Palm oil is endowed with a good mixture of natural antioxidants and together with its balanced composition of the different classes of fatty acids, makes it a safe, stable and versatile edible oil with many positive health and nutritional attributes. In recent times, adverse health concerns from the consumption of trans fatty acids arising from hydrogenation of oils and fats have been the subject of much discussion and controversy. Trans fatty acids when compared with cis fatty acids or unhydrogenated fats have been shown to lower serum HDL cholesterol, raise serum LDL cholesterol and when substituted for saturated fatty acids, increase lipoprotein Lp (a) level, an independent risk factor for the development of coronary heart disease. The idea of which foods, nutrients and supplements are "healthy" is often being amended as new scientific data is presented and then simplified for the consumers. What was once perceived as a healthy diet is often no longer considered as such and vice versa. Dietary recommendations have to change with time and the evidence available. Nutritional recommendations should encourage eating a great variety of nutrient sources within our food supply in moderation. Various lifestyle options to improve health should also be promoted.     

Regulation of Acyl-coenzyme A:Cholesterol Acyltransferase 2 Expression by Saturated Fatty Acids

Objective To verify the regulation of acyl-coenzyme A：cholesterol acyltransferase 2 （ACAT 2）, which is associated with cholesterol metabolism, by saturated fatty acids （SFAs）. Methods Palmitic acid （PA）, the most abundant saturated fatty acid in plasma, and oleic acid （OA）, a widely distributed unsaturated fatty acid, were used to treat hepatic cells HepG2, HuH7, and mouse primary hepatocytes. In addition, PA at different concentrations and PA treatment at different durations were applied in HepG2 cells. In in vivo experiment, three-month male C57/BL6 mice were fed with control diet and SFA diet containing hydrogenated coconut oil rich of SFAs. The mRNA level of ACAT2 in those hepatic cells and the mouse livers was detected with real-time polymerase chain reaction （PCR）. Results In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression （P〈0.01）, whereas treatment with OA showed no significant effect. That effect of PA was noticed gradually rising along with the increase of PA concentration and the extension of PA treatment duration （both P〈0.05）. SFA diet feeding in mice resulted in a short-term and transient increase of ACAT2 expression in vivo, with a peak level appearing in the mice fed with SFA diet for two days （P〈0.05）. Conclusion SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.     

Dietary prevention of coronary heart disease. Effect of dietary fats on arterial thrombosis.

Epidemiological studies indicate that dietary saturated fats are implicated in coronary heart disease (CHD). Human prospective studies have shown that diets low in long chain saturated fatty acids and enriched in linoleic acid are beneficial in CHD-prevention. Experiments in animals have shown that such diets diminish atherosclerosis and the tendency to arterial thrombosis; they also lower the ability of platelets to aggregate in animals and in man. The mechanisms by which these diets produce these effects are not yet completely understood. Platelets and vascular prostaglandin-like substances may be involved as well as platelet membrane fluidity and platelet coagulant activities. On the basis of the available evidence, measures to decrease the intake of long chain saturated fatty acids (concomitant with an enhanced consumption of linoleic acid-rich products) are justified. Although certain marine oils may also have anti-thrombotic properties the possibility of undesirable side effects compels extensive investigation before their wide-spread use can be recommended.     

几个不同产地的小油桐种子含油率及其脂肪酸组成

目的 比较我国的广东、海南、贵州和印度等地所产小油桐种子含油率及其脂肪酸组成.方法 采用索氏抽提法测定小油桐种子的含油率,采用GC-MS对小油桐油的脂肪酸组成进行分析.结果 不同产地的小油桐种子干基含油率分别为32.43%(广东)、31.41%(海南)、37.56%(贵州)和41.04%(印度);GC.MS鉴定出12种脂肪酸成分,其中不饱和脂肪酸分别占总脂肪酸的80.93%(广东)、79.53%(海南)、77.24%(贵州)和78.22%(印度).结论 不同产地的小油桐种子的含油率和脂肪酸组成方面均存在差异,这在小油桐引种与育种过程中应予以考虑.     

蒺藜炒制前后挥发性成分和脂肪油的GC-MS分析

目的:对蒺藜炒制前后挥发性成分和脂肪油进行分析,为科学评价蒺藜炒制意义提供相关化学依据。方法:利用自制实验室炒制装置收集蒺藜炒制过程中挥发出的成分,利用挥发油提取器收集生、炒品挥发油及甲酯化脂肪油中的脂肪酸,用气相色谱-质谱联用法对其组分进行测定和分析。结果:从生蒺藜挥发油中鉴定出14个化合物,炒蒺藜中鉴定出13个,炒制中挥发出的成分鉴定出11个。3类挥发性成分之间的相对含量亦发生变化,生、炒蒺藜中脂肪油含量相近,两者脂肪油中均检出了亚油酸、棕榈酸、硬脂酸、油酸、花生酸、反-9,12-十八碳二烯酸、山嵛酸。结论:蒺藜生、炒品挥发性成分存在一定差异。炒制对蒺藜脂肪油的含量和其中的脂肪酸组分没有影响。     

再次改善膳食模式对北京市房山区张坊村中老年超重或肥胖高血压患者血压和人体成分及血脂谱的影响研究

目的　在前期研究基础上,观察再次改善膳食模式对北京市房山区张坊村中老年超重或肥胖高血压患者血压、人体成分、血脂谱的影响,探讨营养成分通过改变人体成分、血脂谱,从而对血压产生影响的可能机制。方法　2017-05-21至2017-07-01,根据纳入与排除标准,从北京市房山区张坊村245例中老年（45~75岁）村民数据库中,选取超重或肥胖的1级高血压患者54例为研究对象。采用随机数字表法将其分为A组（27例,采用标准均衡膳食）和B组（27例,采用补充抗动脉粥样硬化食疗粉的均衡膳食）。按照剔除标准,最终共纳入30例患者,其中A组15例,B组15例。分别记录患者干预前（T0）、干预中（T1）、干预结束（T2）时血压（收缩压、舒张压）、人体成分〔体质指数（BMI）、体脂含量（BF）、体脂肪量、腰臀比（WHR）、内脏脂肪面积〕、血脂谱〔总胆固醇（TC）、三酰甘油（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）〕及干预前后总能量摄入量、各类食物（主食、叶菜类蔬菜、根茎类蔬菜、盐、食用油、鸡蛋、全脂牛奶、红色肉类、白色肉类、豆腐、水果）摄入量、营养素〔碳水化合物、蛋白质、脂肪、膳食纤维、维生素A（VitA）、维生素B1（VitB1）、维生素B2（VitB2）、维生素C（VitC）、钙、铁、锌、硒、镁、锰、胆固醇、烟酸、叶酸、饱和脂肪酸（SFA）、单不饱和脂肪酸（MUSF）和多不饱和脂肪酸（PUFA）〕摄入量/比例。结果　A组、B组T1、T2时收缩压均低于T0时,T2时舒张压均低于T0时（P<0.05）。A组T1时BMI、体脂肪量、内脏脂肪面积低于T0时,T2时体脂肪量、WHR、内脏脂肪面积低于T0时,T2时WHR低于T1时,T2时内脏脂肪面积高于T1时（P<0.05）;B组T1时BMI、BF、体脂肪量、内脏脂肪面积低于T0时,T2时BMI、BF、体脂肪量、WHR、内脏脂肪面积低于T0时,T2时内脏脂肪面积高于T1时（P<0.05）。A组T2时TC、HDL-C、LDL-C低于T1时,T1时HDL-C高于T0时（P<0.05）;B组T1时TG低于T0时、HDL-C高于T0时,T2时HDL-C高于T0时、TG高于T1时、HDL-C低于T1时（P<0.05）。两组干预前、干预后总能量摄入量比较,差异无统计学意义（P>0.05）;A组、B组干预后总能量摄入量与同组干预前比较,差异无统计学意义（P>0.05）。B组干预前食用油摄入量高于A组（P<0.05）。A组、B组干预后叶菜类蔬菜、根茎类蔬菜、鸡蛋、全脂牛奶、白色肉类、豆腐、水果摄入量高于同组干预前,盐、食用油摄入量低于同组干预前（P<0.05）。B组干预后碳水化合物、硒摄入量低于A组,蛋白质、镁、锰摄入量高于A组（P<0.05）。A组、B组干预后蛋白质、膳食纤维、VitA、VitB1、VitB2、VitC、钙、铁、锌、镁、锰、胆固醇、烟酸、叶酸、SFA、PUFA摄入量及蛋白质摄入比例高于同组干预前（P<0.05）;B组干预后脂肪摄入比例低于干预前,硒摄入量高于干预前（P<0.05）。结论　对北京市房山区张坊村中老年超重或肥胖高血压患者给予标准均衡膳食和补充抗动脉粥样硬化食疗粉的均衡膳食后,其膳食模式得以改善,进而优化人体成分,平稳血脂水平,显著降低血压。     

The amino acid and fatty acid composition of the thermostable lipoprotein ("Antigen 880") of hydatid cyst fluid (HCF)

Analysis for the amino acid composition of "Antigen 880" was carried out by use of double dimension paper chromatography and Biotronik 2,000 automatic amino acid analyzer. By the double dimension paper chromatography, leucine, phenylalanine, tyrosine and alanine were identified as amino acid components of the protein moiety of "Antigen 880". In the Biotronik 2,000 automatic amino acid analyzer showed the concentration of the various amino acids to be as follows: isoleucine, leucine, tyrosine, phenylalanine, lysine and histidine were identified as amino acid constituents of "Antigen 880". Quantitative studies in Biotronik 2,000 analyzer showed the concentration of the various amino acids to be as follows: valine -0.85 mumol/ml; leucine - 0.22 mumol/ml. /ml; iso-leucine - 0.18 mumol/ml; tyrosine - 0.04 mumol/ml, and histidine - 0.02 mumol/ml. The fatty acid composition of the lipid moiety of "Antigen 880" was investigated by use of Gas-Liquid chromatography. In this method, C8:0. C10:0, C12:0, C14:0, C16:0 and C18 were identified as the fatty acid constituents of the lipid moiety of "Antigen 880".     

Effect of coconut oil in plaque related gingivitis — A preliminary report

Background:

Oil pulling or oil swishing therapy is a traditional procedure in which the practitioners rinse or swish oil in their mouth. It is supposed to cure oral and systemic diseases but the evidence is minimal. Oil pulling with sesame oil and sunflower oil was found to reduce plaque related gingivitis. Coconut oil is an easily available edible oil. It is unique because it contains predominantly medium chain fatty acids of which 45-50 percent is lauric acid. Lauric acid has proven anti inflammatory and antimicrobial effects. No studies have been done on the benefits of oil pulling using coconut oil to date. So a pilot study was planned to assess the effect of coconut oil pulling on plaque induced gingivitis.

Materials and Methods:

The aim of the study was to evaluate the effect of coconut oil pulling/oil swishing on plaque formation and plaque induced gingivitis. A prospective interventional study was carried out. 60 age matched adolescent boys and girls in the age-group of 16-18 years with plaque induced gingivitis were included in the study and oil pulling was included in their oral hygiene routine. The study period was 30 days. Plaque and gingival indices of the subjects were assessed at baseline days 1,7,15 and 30. The data was analyzed using paired t test.

Results:

A statistically significant decrease in the plaque and gingival indices was noticed from day 7 and the scores continued to decrease during the period of study.

Conclusion:

Oil pulling using coconut oil could be an effective adjuvant procedure in decreasing plaque formation and plaque induced gingivitis.     

江门市区食品中沙门菌污染状况及其耐药性调查

目的了解江门市区各类食品中沙门菌污染和耐药状况。方法采用国家标准检测方法,并参照全国食源性检测工作手册,采集市区集贸市场、大型超市及个体熟食销售点等的生肉类、生奶等9类食品检测沙门菌,检出菌株做药物敏感试验。结果从9类550份食品中的31份检出沙门菌31株,阳性率为5．64%。其中以生肉类（生猪肉、生鸡内、生羊肉、生牛肉）阳性率最高,分别为11．67％、10．00％、10．00％和9．09％,其次为非定型包装熟肉类,阳性率为3．70％。生奶和冰洪淋均未检出沙门菌。捡出沙门菌对20种抗生素中的17种出现不同程度的耐药。结论本市区9类食品中有7娄存在沙门菌污染和发生食物中毒的潜在危险,应加强食品卫生管理尤其是生肉类和非定型包装熟内的管理,控制动物饲料亚治疗抗生素的使用井严格遵守休药期对防止耐药菌株、控制食源性疾病很有必要。     

Trans fatty acids (TFA): analysis,occurrence, intake and clinical relevance

More than one quarter of total daily calories are normally provided by fatty acids which contain at least one double bond. The usual configuration of these double bonds is the cis configuration. Trans fatty acids (TFA) are formed in technological and microbiological processes by isomerization of cis double bonds to trans double bonds. In the 1990s, there was public health concern about epidemiological studies suggesting that TFA increase the risk of coronary heart disease. High intakes of TFA may have an influence on total cholesterol and other blood parameters; but on the other hand there have been a lot of studies which have not been able to confirm these results. TFA are formed in varying amounts during the industrial hydrogenation of vegetable oils and in the first stomach of ruminants. Regular margarines contain varying contents of partially hydrogenated vegetable oils, and therefore of TFA. The main dietary TFA are the trans octadecenoic acids, which contribute to approximately 80-90 % of total TFA content in foods. The predominant isomer of milk fat is trans vaccenic acid, which is directly influenced by ruminant feeding conditions. For a reliable identification and quantification of TFA in foods and other biological matrices it is necessary to use a combination of chromatographic methods (GC-FID, GC-MS, GC-FTIR, Ag superset +-HPLC).     

对叶大戟种子中脂肪酸的气相色谱-质谱联用分析

目的研究对叶大戟种子油脂成分。方法采用索式提取法提取对叶大戟种子油,气相色谱-质谱联用(GC-MS)法鉴定化学成分,归一化法测定各成分相对含量。结果对叶大戟种子油中共鉴定出10种脂肪酸,其主要脂肪酸成分为棕搁酸5.608%,硬脂酸2.219%,油酸13.857%,亚油酸17.623%,a-亚麻酸50.854%。结论对叶大戟种子因富含人体必须脂肪酸而极具开发价值,尤其是a-亚麻酸和亚油酸占到了对叶大戟种子油的68.477%。     

乙酰辅酶A羧化酶抑制剂的研究进展

非酒精性脂肪肝病是以肝细胞内脂肪过度沉积为主要特征的代谢性疾病，脂肪主要以甘油三酯的形式存在，由甘油和脂肪酸通过酯化作用形成；而且肿瘤细胞中脂肪酸的合成异常活跃，明显高于正常细胞，为肿瘤细胞旺盛的增殖、发育过程中生物膜的形成、信号分子和能量的产生提供必要的脂质底物。乙酰辅酶A羧化酶(acetyl-CoA carboxylase，ACC)是脂肪酸从头合成过程的限速酶，同时也是催化该脂肪酸合成通路中第一步反应的酶；其催化生成的产物丙二酰辅酶A亦能抑制脂肪酸的氧化。因此，ACC抑制能降低脂肪酸合成和促进脂肪酸氧化，降低体内脂肪酸的含量，进而减弱肝细胞内脂肪的堆积来达到改善非酒精性脂肪肝病；同时体内脂肪酸含量的降低使肿瘤细胞发育所必须的脂质底物得不到满足，从而能够抑制肿瘤组织的发育，所以乙酰辅酶A羧化酶抑制剂有望成为新型治疗非酒精性脂肪肝病和肿瘤的药物。本文对ACC的结构特点、作用机制及其抑制剂的研究进展进行了综述。