LINOLENIC ACID, AN ESSENTIAL FATTY ACID?

Several species of fish require dietary linolenic acid and other ω3 fatty acids. While there is no evidence, by the usual criteria, for dietary requirement in warm-blooded animals. 22: 6ω9 is a major constituent of phospholipids in brain and retina of many species including man.     

脂肪酸对糖尿病模型大鼠血磷脂脂肪谱的影响

目的　观察富含n - 6和n - 3多不饱和脂肪酸 (PUFA)饲料对自发性 2型糖尿病模型OtsukaLong -E vansTokushimaFatty(OLETF)大鼠糖代谢及血清磷脂 (S -PL)中脂肪酸 (FA)组成的影响。 方法　将 2 0只 14周龄雄性OLETF大鼠随机分为 2组。两组大鼠饲料总能量相同 ,其中饱和脂肪酸 (SFA)、单不饱和脂肪酸 (MUFA)和PU FA的百分含量亦相同 ,但分别富含n - 6PUFA〔4 1 6mol/ (10 0mol·脂肪 )〕和n - 3PUFA〔2 0 4mol/ (10 0mol·脂肪 )〕 ,饮食干预 10周。第 2 4周时实施口服糖耐量试验 (OGTT)、胰岛素水平测定和S -PL中FA组成测定。结果　干预期间 ,两组大鼠总进食量及体重增长无显著性差异 ;干预后OGTT及胰岛素水平测定表明 ,n - 3组相对于n - 6组具有较好的胰岛素敏感性。n - 3组大鼠S -PL中 18∶1(n - 9)、MUFA总量、18∶2 (n - 6 )、各n - 3系PUPA百分含量较n- 6组高 ,n - 6PUFA总量、2 0∶4 (n - 6 )百分含量较低。结论　n - 3PUFA的摄入相对于n - 6PUFA对OLETF大鼠的糖代谢有益 ,OLETF大鼠S -PL的FA组成受到饲料中FA的影响 ,但并不是其直接反应。     

动植物油脂中反式脂肪酸测定方法的建立

目的建立适合国内条件的动植物油脂中反式脂肪酸测定方法,为国标方法提供依据。方法选择普通植物油、动物油和氢化植物油三个大类共9种动植物油脂样品,参照国际标准经部分修改,建立了适合国内条件的反式脂肪酸气相色谱分析及用面积归一法定量的测定方法,并进行了重复性测定和实验室间的验证。结果在实验条件下,油脂中脂肪酸可以得到很好的分离;除个别含量极低的脂肪酸外,各脂肪酸组分10次分析结果的相对标准偏差均小于10%,其中反式脂肪酸总和的RSD值在豆油和氢化豆油中分别是2.0%和0.3%;实验室间验证结果也表明,该方法在不同实验室间的结果有很好的一致性,豆油、氢化豆油、猪油三种样品的反式脂肪酸总和的RSD值分别是5.0%、1.1%和4.6%,均远小于10%。结论该检测方法实验室内和实验室间的精密度均较高,且所需仪器比较普及,操作步骤简单易行,分析时间短,适合国内开展,可作为我国动植物油脂反式脂肪酸的测定方法之一。     

TRANS FATTY ACIDS IN FOODS

The trans fatty acid contents of foods as determined by capillary gas-liquid chromatography are presented. Mayonnaise had the least amount and margarine the most.     

Increasing trends in dietary total fat and fatty acid intake among Korean children: using the 2007–2017 national data

BACKGROUND/OBJECTIVESThe prevalence of obesity has been increasing in Korean children. As an unhealthy diet is known as one of the major determinants of childhood obesity, assessing and monitoring dietary fat intake of children is needed.SUBJECTS/METHODSThis analysis included 9,998 children aged 3–11 yrs from the 2007–2017 Korea National Health and Nutrition Examination Surveys. Dietary data were obtained from a single 24-h dietary recall. Intakes of total fat and fatty acids, including saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), n-3 fatty acid (n-3 FA), and n-6 fatty acid (n-6 FA) were evaluated as the absolute amount (g) and proportion of energy from each fatty acid (% of energy). The total fat and SFA intake were also assessed according to compliance with dietary guidelines. Linear trends in the dietary fats intake across the survey period were tested using multiple regression models.RESULTSTotal fat intake significantly increased from 38.5 g (20.3% of energy) to 43.4 g (23.3% of energy) from 2007 to 2017. This increase was mainly accounted for the increases in intakes of SFA (7.2% to 8.4% of energy) and MUFA (6.2% to 7.5% of energy). PUFA intake increased from 4.4 to 4.7% of energy during the 11-yrs period: from 0.57 to 0.63% of energy for n-3 FA and from 3.8 to 4.1% of energy for n-6 FA. The proportions of children who consumed amounts exceeding the dietary guidelines for total fat and SFA significantly increased from 2007 to 2017, with increases from 9.8% to 17.4% for total fat and from 36.9% to 50.9% for SFA.CONCLUSIONSProminent increasing trends in the consumption of total fat and SFA but tiny change in n-3 FA intake were observed in Korean children. The healthy intake of dietary fats should be emphasized in this population.     

Food behaviors accounting for the recent trends in dietary fatty acid profiles among Korean adults

BACKGROUND/OBJECTIVESThis study examined the changes in food behaviors of dietary fatty acids over 2007–2018 among Korean adults.SUBJECTS/METHODSThis study used data from the 4th (2007–2009), 5th (2010–2012), 6th (2013–2015), and 7th (2016–2018) Korea National Health and Nutrition Examination Surveys. A total of 46,307 adults aged 19–64 yrs were selected and dietary data were obtained from a single 24-h recall. In the 4th and 7th data, the major food sources for each fatty acid based on the contributing percentage of the food item were compared. The consumption trends in the major food sources were presented as grams per day over 2007–2018 and compared across the survey periods using the multiple regression model.RESULTSFrom 2007 to 2018, for total fat, saturated fatty acid (SFA), and monounsaturated fatty acid, the contribution of animal food sources, including beef, chicken, and eggs increased but plant food sources (e.g., tofu, soybean, and plant oil) decreased. As polyunsaturated fatty acid sources, mayonnaise, eggs, and bread showed higher contributions, whereas soybean and tofu showed lower contributions in the 7th data compared to the 4th data. For n-3 fatty acids, the contribution of fish decreased between the 4th and 7th data. Over 12 yrs, the significant increases in the absolute amount of consumption from animal sources were observed. In contrast, decreases in the consumption from plant sources and fish were seen across the survey periods.CONCLUSIONSIn Korean adults, increases in the intake of dietary fatty acids along with changes in the food behaviors during 2007–2018 have evoked great concern for SFA intake, which is a cardiovascular disease risk factor. Healthy food sources of dietary fatty acids should be emphasized in this population.     

Interesterified fats: What are they and why are they used? A briefing report from the Roundtable on Interesterified Fats in Foods

Interesterification rearranges the position of fatty acids within triacylglycerols, the main component of dietary fat, altering physical properties such as the melting point and providing suitable functionality for use in a range of food applications. Interesterified (IE) fats are one of a number of alternatives which have been adopted to reformulate products to remove fats containing trans fatty acids generated during partial hydrogenation, which are known to be detrimental to cardiovascular health. The use of IE fats can also reduce the saturated fatty acid (SFA) content of the final product (e.g. up to 20% in spreads), while maintaining suitable physical properties (e.g. melt profile). A novel analysis was presented during the roundtable which combined data from the UK National Diet and Nutrition Survey (2012/2013–2013/2014) with expert industry knowledge of the IE fats typically used in food products, to provide the first known estimate of population intakes of IE fats among UK children and adults. IE fats were found to contribute approximately 1% of daily energy across all ages. The major contributors to overall IE fat intakes were fat spreads (~54%) and bakery products (~22%), as well as biscuits (~8%), dairy cream alternatives (~6%) and confectionery (~6%). Increasing use of IE fats could contribute towards reducing total SFA intakes in the population, but would depend on which food products were reformulated and their frequency of consumption among sub‐groups of the population. Studies comparing the effect of IE and non‐IE fats on markers of lipid metabolism have not shown any consistent differences, either in the fasted or in the postprandial state, suggesting a neutral effect of IE fats on cardiovascular disease risk. However, these studies did not use the type of IE fats present in the food supply. This issue has been addressed in two studies by King's College London, which measured the postprandial response to a commercially relevant palm stearin/palm kernel (80:20) IE ‘hard stock’, although again no consistent effects of the IE fat on markers of lipid metabolism were found. Another study is currently investigating the same IE hard stock, consumed as a fat spread (blended with vegetable oil), and will measure a broader range of postprandial cardiometabolic risk factors. However, further long‐term trials using commercially relevant IE fats are needed. Subsequent to the roundtable, a consumer survey of UK adults (n = 2062; aged 18+ years) suggested that there is confusion about the health effects of dietary fats/fatty acids, including trans fats and partially hydrogenated fats. This may indicate that providing evidence‐based information to the public on dietary fats and health could be helpful, including the reformulation efforts of food producers and retailers to improve the fatty acid profile of some commonly consumed foods.     

Effects of Highly Consumed Dietary Oils on Several Hepatic Transaminases and Lipid Oxidation in Chick

The incidence of cardiovascular disease is well correlated with diets high in saturated fatty acids (such as butter). On the other hand, oils, which are rich in unsaturated fatty acids (e.g., sunflower oil and corn oils), reduce cholesterol synthesis and thus show protective effects against arteriosclerosis. However, sunflower oil and corn oil are also considered as risk factors for their sensitivities to free radical formation because of their high contents of polyunsaturated fatty acids (PUFAs). The aim of the present study described herein was to investigate the production of reactive oxygen metabolites (an indicator of oxidative stress) and the activities of several transaminases (markers of hepatic injury) in chick liver treated with highly consumed dietary oils (differing in the degree of saturation). The animals were randomly assigned to six groups of 29 and fed dietary butter, margarine, olive oil, sunflower oil, or corn oil for 2 months. The results indicated that the level of reactive oxygen metabolites (ROM) was lowest in the dietary butter-fed group but highest in the corn oil-fed group. Similarly, the activities of all transaminases measured were lowest in the butter group, and in the margarine-fed group only the Gama-glutamyl transaminase activity was lowest as compared to the control group. From these findings, it was concluded that the dietary butter was the most resistant oil to lipid oxidation, whereas corn oil was the most susceptible one, which may thus challenge the antioxidant defense system and increase the susceptibility of tissues to degradation products of lipid oxidation.     

高脂饲料对OLETF大鼠糖代谢及血清磷脂脂肪酸组成的影响

目的:观察高脂饲料对自发性2型糖尿病模型OLETF大鼠糖代谢及血清磷脂脂肪酸组成的影响。方法:将20只14w雄性OLETF大鼠随机分为两组,分别以高脂及标准饲料喂饲10w,两种饲料中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸占总脂肪酸的百分含量相似。大鼠第24w龄时进行口服糖耐量试验,同时测定大鼠的胰岛素水平和血清磷脂脂肪酸组成。结果:实验期间两组大鼠总进食量无统计学差异,但高脂饲料组大鼠体重明显高于标准饲料组(P<0.01);口服糖耐量试验和胰岛素水平测定结果表明,两组大鼠的糖代谢状态无统计学差异;血清磷脂脂肪酸组成中,除总n-6PUFA和18:3(n-3)的百分含量无统计学差异外,其他各脂肪酸组分在两组间的差异均具有统计学意义(P<0.01)。结论:在饲料脂肪酸组成保持可比的情况下,饲料脂肪量的增加可使OLETF大鼠的体重明显增加,而对糖代谢的影响不明显,同时对OLETF大鼠血清磷脂脂肪酸组成产生明显影响。     

PARTIALLY HYDROGENATED FATS IN THE DIETS OF NURSING MOTHERS: EFFECT ON CONTENTS OF TRANS FATTY ACIDS AND PROSTAGLANDINS IN MILK

Consumption of trans fats rapidly increases the amounts of trans fatty acids in human milk, but does not alter contents of prostaglandins.     

中长链脂肪酸食用油对不同BMI男性高甘油三酯血症体脂肪的影响

目的探讨中长链脂肪酸食用油对不同BMI男性高甘油三酯血症患者体成分的影响。方法将74名男性高甘油三酯血症患者随机分为中长链脂肪酸食用油组和长链脂肪酸食用油组。各组再按BMI分为体重正常组、超重组和肥胖组。控制每日膳食摄人量及食用油摄入量（25～30g／人／d），规定运动方式，实验周期为8周。分别于实验开始前和8周后对两组实验对象进行人体成分测量（身高、体重、体脂肪量、腰围、臀围等）、腹部CT扫描（腹部脂肪总面积、腹部皮下脂肪面积）。结果获得男性有效数据67例，长链脂肪酸食用油组34例；中长链脂肪酸食用油组33例，两组BMI分布无显著性差异。实验过程中两组膳食摄人量及体力活动时间无显著性差异，实验前两组间体成分测量指标、腹部CT扫描结果也无显著性差异。实验结束后，体型超重人群中长链脂肪酸食用油组体重、腰围、肩胛下皮褶厚度、体脂肪重、腹部脂肪总面积、腹部皮下脂肪面积显著降低，且降低的程度明显优于长链组。结论在合理膳食条件下，使用中长链脂肪酸食用油可减轻男性超重高甘油三酯血症患者的体重、体脂肪、皮下脂肪，而对体型正常和肥胖者效果不明显。     

Fatty acid consumption pattern of Americans: 1987–1988 USDA Nationwide Food Consumption Survey

This study characterized the fatty acid intake pattern and the contribution of different food groups to the fatty acid intake of Americans using the U.S. Department of Agriculture's 1987–1988 Nationwide Food Consumption Survey. The fatty acid intake was estimated using three-day food consumption data for children age 6–11 and for males and females age 12–19, 20–39 and 40 and older. Palmitic acid was the predominant saturated fatty acid (SFA) in the diet for all age sex groups, contributing 52–57% of SFA intake. Oleic acid was the primary monounsaturated fatty acid (MUFA) for all age sex groups, comprising 91–95% of MUFA intake. Linoleic acid was the principle polyunsaturated fatty acid (PUFA) for all age sex groups, contributing 87–92% of PUFA intake. The Milk and Milk Products group was the major contributor of the short chain SFA and lauric and myristic acids. Meat, Poultry and Meat Mixtures were the main sources of palmitic and stearic acids. Grain Products contributed appreciably to the long chain SFA intake. Oleic acid was obtained mainly from Meat, Poultry, Fish and Mixtures. Yeast breads, rolls, cakes, cookies and pastries were the main contributors of linoleic acid intake. A variety of animal and vegetable products contributed to the linolenic acid and C_18:4+20:4 intake, while fish and shellfish were the main sources of C_20:5+22:6 fatty acids. The contribution of the various food groups to intake of individual fatty acids was similar for both males and females. The results of the present study indicate that a wide variety of food groups contribute to the total fat intake Americans.     

Fat intakes of children with PKU on low phenylalanine diets

BACKGROUND: As part of a study on the effects of a fat-supplemented phenylalanine (phe)-free protein substitute on the fatty acid status of children with phenylketonuria (PKU), the adequacy of the diets of children aged 1-10 years for fat and essential fatty acids (EFA) was assessed. METHODS: Subjects randomized in a 1 : 1 ratio to a phe-free protein substitute supplemented with EFA (test-treatment group) or a phe-free, fat-free protein substitute (control group) for 20 weeks. 3-day semi-weighed records of food intakes collected at the end of the study period. RESULTS: Total fat and alpha-linolenic acid (alpha-LA) intakes were found to be poor in the control group (n = 19). Those in the test-treatment group (n = 24) had higher fat and EFA intakes (P < 0.05), bringing intakes closer to population norms. The youngest children (<5 years of age) in the control group appeared to be especially vulnerable to poor fat intakes because of the restricted diversity of their diets and, regardless of age, alpha-LA intakes by this group were poor compared with the non-PKU population. CONCLUSIONS: The quantity and quality of fat in the diets of children with PKU, in particular young children, should be given careful consideration in trying to optimize the ratio of linoleic acid: alpha-LA in their diets and in satisfying the requirements of this group for fat and alpha-LA.     

Update on alpha-linolenic acid

Consumption of omega 3 fatty acids is known to have health benefits. For many years, the importance of the only member of the omega 3 family considered to be essential, alpha-linolenic acid (ALA), has been overlooked. Current research indicates that ALA, along with its longer chain metabolites, may play an important role in many physiological functions. Potential benefits of ALA include cardioprotective effects, modulation of the inflammatory response, and a positive impact on both central nervous system function and behavior. Recommended levels for ALA intake have been set, yet the possible advantages of its consumption are just being revealed.     

The ω-3 and ω-6 fats in meals: a proposal for a simple new label

Objective

The ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are separate essential dietary fatty acids that play a key role in many physiologic processes in higher animals. The content of these PUFAs is relatively well described for many individual food components. Our goal in this study was to analyze the PUFA content of whole meals and produce a simple measurement to estimate the intake of these fatty acids.

Methods

The fatty acid profile and macronutrient composition were determined for a range of fast food, cuisine (restaurant-prepared), and home-prepared whole meals commonly consumed by Australians.

Results

Across the different meals there was significant variation in protein (4-fold), fat (13-fold), and carbohydrate (23-fold) contents. With regard to the fatty acid profile, saturated and monounsaturated fatty acids made up approximately 80% of total fatty acids for most meals. The ω-6 PUFAs were substantially more abundant than ω-3 PUFAs for most meals. The balance of dietary ω-3 and ω-6 PUFAs is an important determinant of their metabolic effects within the body, and accordingly we calculated the percentage of the total PUFA comprised of ω-3 PUFAs and referred to this as the PUFA Balance. This parameter showed the greatest variation among the different meals (>45-fold).

Conclusion

The relative proportions of ω-3 and ω-6 PUFAs vary greatly across meals. PUFA Balance is a useful tool that will allow individuals to more easily monitor and balance their intake of ω-3 and ω-6 fats.     

FISH OILS AS HYPOTRIGL YCERIDEMIC AGENTS

Fish oils, partially hydrogenated or not, increase fatty acid oxidation in the liver, but only those with polyunsaturated fatty acids of the n-3 type are strongly hypotriglyceridemic.     

ω-3脂肪酸与冠状动脉性心脏病

ω-3多不饱和脂肪酸对冠状动脉性心脏病有潜在的预防和治疗作用，其保护心血管的可能作用机制包括：（1）抗心律失常；（2）调节脂代谢；（3）延缓动脉粥样硬化斑块的发展。     

EFFECTS OF FEEDING DIHOMO- γ-LINOLENIC ACID (20: 3ω6) IN MAN

Feeding 1 g to 2 g daily of 20: 3ω6 to humans rapidly increased the proportion of this fatty acid in plasma and in platelet lipids, as well as the formation of PGE₁ by platelets. Conversion of 20: 3ω6 to arachidonic acid by the liver appears to be greater in rodents than in man.