Nationwide product reformulations to reduce trans fatty acids in Canada: when trans fat goes out, what goes in?

The impact of recent efforts to reduce the content of industrially produced trans fatty acids (TFA) in foods has not been systematically assessed in any country. Concerns exist that food manufacturers/restaurants may replace TFA with saturated fat acids (SFA), rather than cis unsaturated fats, or increase the total fat content. We present findings from a national systematic assessment of grocery and restaurant foods likely to contain TFA in Canada in 2005-2007. Of the total of 221 assessed products, 92 (42%) contained TFA (> or = 5% of fatty acids) on initial assessment. Of an unselected sample assessed more than once, 72% were reformulated during 2005-2007: mean+/-s.d. TFA levels decreased from 26+/-13 to 2+/-4%. Following reformulation, one product had similar TFA+SFA content; all others had decreased TFA+SFA and increased cis unsaturated fat content. The total fat content was generally unaffected. The findings suggest that manufacturers/restaurants generally take advantage of costs and efforts of reformulation to not only reduce TFA but also increase the content of cis unsaturated fats.     

Exchanging partially hydrogenated fat for palmitic acid in the diet increases LDL-cholesterol and endogenous cholesterol synthesis in normocholesterolemic women

Partial hydrogenation of oil results in fats containing unusual isomeric fatty acids characterized by cis and trans configurations. Hydrogenated fats containing trans fatty acids increase plasma total cholesterol (TC) and LDL-cholesterol while depressing HDL-cholesterol levels. Identifying the content of trans fatty acids by food labeling is overshadowed by a reluctance of health authorities to label saturates and trans fatty acids separately. Thus, it is pertinent to compare the effects of trans to saturated fatty acids using stable isotope methodology to establish if the mechanism of increase in TC and LDL-cholesterol is due to the increase in the rate of endogenous synthesis of cholesterol. Ten healthy normocholesterolemic female subjects consumed each of two diets containing approximately 30% of energy as fat for a fourweek period. One diet was high in palmitic acid (10.6% of energy) from palm olein and the other diet exchanged 5.6% of energy as partially hydrogenated fat for palmitic acid. This fat blend resulted in monounsaturated fatty acids decreasing by 4.9 % and polyunsaturated fats increasing by 2.7%. The hydrogenated fat diet treatment provided 3.1% of energy as elaidic acid. For each dietary treatment, the fractional synthesis rates for cholesterol were measured using deuterium-labeling procedures and blood samples were obtained for blood lipid and lipoprotein measurements. Subjects exhibited a higher total cholesterol and LDL-cholesterol level when consuming the diet containing trans fatty acids while also depressing the HDL-cholesterol level. Consuming the partially hydrogenated fat diet treatment increased the fractional synthesis rate of free cholesterol. Consumption of hydrogenated fats containing trans fatty acids in comparison to a mixtur e of palmitic and oleic acids increase plasma cholesterol levels apparently by increasing endogenous synthesis of cholesterol.     

银离子固相萃取-气相色谱法检测食品中的反式脂肪酸

[目的]评价银离子固相萃取结合气相色谱（silver ion solid phase extraction-gas chromatography,Ag＋-SPE/GC）对市售加工食品中反式脂肪酸（trans fatty acids,TFA）的定性和定量检测效果。[方法]采用Ag＋-SPE小柱预分离牛肉火腿、豆奶粉和巧克力威化中的TFA甲酯,然后按食品中反式脂肪酸的检测标准（GB/T 22110—2008）进行气相色谱检测。[结果]该方法对食品中TFA甲酯异构体的回收率为71.0%~90.5%,相对标准偏差（relative standard deviation,RSD）均小于13%,该方法对TFA甲酯单标的回收率为84.1%~98.7%,RSD均小于5.6%;最低检出限为10mg/100g（按脂肪计）。牛肉火腿、豆奶粉和巧克力威化中TFA含量依次为37.26mg/100g、24.64mg/100g和162.85mg/100g;3种食品中t C18∶1含量较高,t C18∶2次之,t C18∶3较少;均未检测到t C16∶1。[结论]Ag＋-SPE/GC方法灵敏度较高、分离效果好、重现性好,可以避免顺式脂肪酸和饱和脂肪酸的干扰,适用于乳、肉、巧克力及其制品等食物中TFA含量的测定。     

Dietary fatty acids affect plasma markers of inflammation in healthy men fed controlled diets: a randomized crossover study

BACKGROUND: The effect of individual dietary fatty acids on emerging risk factors for cardiovascular disease that are associated with subclinical inflammation is unknown. OBJECTIVE: The goal was to evaluate the role of dietary fat and specific fatty acids, especially trans fatty acids, in altering concentrations of markers of inflammation in humans fed controlled diets. DESIGN: In a randomized crossover design, 50 men consumed controlled diets for 5 wk that provided 15% of energy from protein, 39% of energy from fat, and 46% of energy from carbohydrate. Eight percent of fat or fatty acids was replaced across diets with the following: cholesterol, oleic acid, trans fatty acids (TFAs), stearic acid (STE), TFA+STE (4% of energy each), and 12:0-16:0 saturated fatty acids (LMP). RESULTS: Fibrinogen concentrations were higher after consumption of the diet enriched in stearic acid than after consumption of the carbohydrate diet. C-reactive protein concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet, but were not significantly different after consumption of the TFA and TFA+STE diets than after consumption of the LMP diet. Interleukin 6 concentrations were lower after consumption of the oleic acid diet than after consumption of the LMP, TFA, and STE diets. E-selectin concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet. Consumption of the TFA but not the TFA+STE diet resulted in higher E-selectin concentrations than did the LMP diet. CONCLUSIONS: These data provide evidence that dietary fatty acids can modulate markers of inflammation. Although stearic acid minimally affects LDL cholesterol, it does appear to increase fibrinogen concentrations.     

Milk fat depression in C57Bl/6J mice consuming partially hydrogenated fat

Mice of the C57Bl/6J strain were maintained on diets in which the unsaturated fatty acids were all cis fatty acids (CFA) or a mixture of CFA and trans fatty acids (TFA). The fats used were mixtures of corn oil, olive oil, cocoa butter, margarine and shortening blended to yield similar fatty acid compositions, except for the ratio of the CFA to TFA and the percentage of linoleic acid (EFA). Regardless of the level of fat (20 or 40 energy %) or the level of EFA (2 to 12 energy %), diets with TFA decreased the percentage of fat in mouse milk. When lactating females raised on the CFA diets were crossed to the TFA diets, TFA appeared in the milk at 12 h postcross, and within 4 d postcross the percent of milk fat was decreased to levels similar to that of nursing females raised continuously on the TFA diets. Conversely, lactating females crossed from TFA to CFA diets produced milk with percentage fat values and fatty acid compositions that approached those seen in nursing females fed the CFA diets continuously. The possible involvement of TFA in the classical milk fat depression phenomenon in ruminants and its potential relevance in human lactation are discussed.     

Occurrence and biochemical characteristics of natural bioactive substances in bovine milk lipids

Bovine milk lipids (BML) contain a number of bioactive substances with positive as well as negative properties, mainly in the class of fatty acids. Besides trans fatty acids (TFA), conjugated linoleic acids (CLA) are of particular interest. Apart from ruminant meat products the main source of CLA in food are BML. Although TFA as well as saturated fatty acids (12:0-16:0) are thought to be positively correlated with atherosclerosis and coronary heart disease, CLA are considered antiatherogenic. Further, CLA are reported to reduce adipose fat and to have anticarcinogenic properties. The varying CLA and TFA contents of lipids from milk and dairy products are positively correlated with one another. However, TFA are also negatively correlated with 12:0-16:0 in BML. Anticarcinogenic effects are also ascribed to butyric acid as well as to some phospholipids and ether lipids present in BML. Moreover, the essential fatty acids 18:2n-6 and 18:3n-3 are found in BML which are involved in a variety of biochemical processes and thus have numerous functions in human metabolism. Contents of the individual bioactive components of BML are summarised taking into account also seasonal variations. The total content of bioactive substances in BML is approximately 75 % but their overall impact on human health considering benefits and drawbacks is difficult to assess.     

Intake of fatty acids in western Europe with emphasis on trans fatty acids: the TRANSFAIR Study

OBJECTIVE: To assess the intake of trans fatty acids (TFA) and other fatty acids in 14 Western European countries. DESIGN AND SUBJECTS: A maximum of 100 foods per country were sampled and centrally analysed. Each country calculated the intake of individual trans and other fatty acids, clusters of fatty acids and total fat in adults and/or the total population using the best available national food consumption data set. RESULTS: A wide variation was observed in the intake of total fat and (clusters) of fatty acids in absolute amounts. The variation in proportion of energy derived from total fat and from clusters of fatty acids was less. Only in Finland, Italy, Norway and Portugal total fat did provide on average less than 35% of energy intake. Saturated fatty acids (SFA) provided on average between 10% and 19% of total energy intake, with the lowest contribution in most Mediterranean countries. TFA intake ranged from 0.5% (Greece, Italy) to 2.1% (Iceland) of energy intake among men and from 0.8% (Greece) to 1.9% among women (Iceland) (1.2-6.7 g/d and 1.7-4.1 g/d, respectively). The TFA intake was lowest in Mediterranean countries (0.5-0.8 en%) but was also below 1% of energy in Finland and Germany. Moderate intakes were seen in Belgium, The Netherlands, Norway and UK and highest intake in Iceland. Trans isomers of C18:1 were the most TFA in the diet. Monounsaturated fatty acids contributed 9-12% of mean daily energy intake (except for Greece, nearly 18%) and polyunsaturated fatty acids 3-7%. CONCLUSION: The current intake of TFA in most Western European countries does not appear to be a reason for major concern. In several countries a considerable proportion of energy was derived from SFA. It would therefore be prudent to reduce intake of all cholesterol-raising fatty acids, TFA included.     

Changes in dietary intake and food sources of saturated and cis and trans unsaturated fatty acids in Costa Rican adolescents: 1996 versus 2006

ObjectiveTo identify how dietary intake and food sources of saturated (SFA) and cis (PUFA) and trans (TFA) unsaturated fatty acids in the diet of Costa Rican adolescents changed from 1996 to 2006—a period with several public health nutrition changes.MethodsCross-sectional comparisons used data from measured food records of 133 adolescents (ages 12–17 y) surveyed in 1996 and a similar group of adolescents surveyed in 2006. Values obtained in 1996 and 2006 were compared with the current World Health Organization guidelines for chronic disease prevention.ResultsAdolescents surveyed in 2006 reported a significantly higher mean daily energy intake from linoleic acid (LA) and alpha-linolenic acid (ALA) (0.9% and 7.8%, respectively) compared with the 1996 cohort, whereas SFA and TFA were significantly lower (9.5% and 1.3%, respectively). Food sources of fat also changed. In 2006, 2% of SFA in the diet came from palm shortening (compared with 34% in 1996); 39% of TFA came from ruminant-derived foods (in 1996, soybean oil was the main contributor of TFA, 34%), and bakery products (mainly pre-packaged cookies) provided 25% of the source of TFA, compared with only 11% in 1996. Dietary fatty intake of Costa Rican adolescents in 2006 is closer to WHO guidelines compared with 1996.ConclusionsAfter public health initiatives that changed fatty acid profile of most foods, intakes of TFA, SFA, and food sources of fatty acids in adolescents’ diets improved. Public health nutrition efforts should continue to strengthen diets that are low in SFA and TFA and higher in ALA content among Costa Rican adolescents.     

The relation between trans fatty acid levels and increased risk of myocardial infarction does not hold at lower levels of trans fatty acids in the Costa Rican food supply

Data on the effects of recent industrial modifications that reduced the trans fatty acid (TFA) content in food supplies are scarce. In this study, incident cases (n = 1797) of a first nonfatal myocardial infarction (MI) were matched with population controls (n = 1797) for age, sex, and area of residence in Costa Rica. Odds ratio (OR) and 95% CI were calculated from conditional logistic regressions before and after a reduction of TFA in Costa Rican foods. Initially, the median quintiles of total adipose tissue TFA were 1.85, 2.47, 2.99, 3.58, and 4.40 g/100 g; total TFA was positively associated with increased MI risk after adjusting for established risk factors (OR by quintiles of total TFA: 1.00, 1.37, 1.91, 1.86, 3.28; P for trend < 0.001). This association was mostly due to 18:2 trans. In contrast, after industrial modification, median quintiles of total adipose tissue TFA were 1.84, 2.26, 2.57, 2.88, and 3.42 g/100 g; the association with MI was no longer significant (OR by quintiles of total TFA: 1.00, 0.78, 1.03, 0.88, and 1.03; P for trend = 0.65). Adipose tissue 18:1 trans fatty acids were not associated with risk of MI before or after the modification. Although to date there are no TFA regulations in Costa Rica, it appears that indirect international influence has led to a TFA reduction in the food supply and, consequently, to a reduction in the risk of nonfatal MI. The public health sector of Costa Rica should regulate food labeling and content to ensure very low levels of TFA intake.     

Trans fatty acids in the New Zealand food supply

Adverse health effects from the consumption of trans fatty acids (TFA) have led to efforts to decrease the consumption of these lipids. There is a need for up to date information on TFA levels in foods to support decision-making by regulators on labelling and health claims. This paper reports the results from a 2006 survey of New Zealand manufactured food items for fatty acid content, including TFA, determined using gas chromatography. The TFA levels in snack bars, margarines/table spreads, biscuits and cakes, pies and pastries were all below 10 g/100 g fatty acids (less than 3.5 g/100 g product). Also reported are results from a 1998 survey of margarines and table spreads which are compared with those from a previously published 1996 survey conducted by the same organisation. The conclusion is that the TFA content of foods in New Zealand has declined over the previous decade, with a likely decrease in consumption of these lipids by New Zealanders.     

Intake of trans fatty acid-rich hydrogenated fat during pregnancy and lactation inhibits the hypophagic effect of central insulin in the adult offspring

OBJECTIVE: Using rats we examined whether maternal intake of hydrogenated fat rich in trans fatty acids affects brain fatty acid profile, hypothalamic content of insulin receptor and insulin receptor substrate-1 proteins, and the hypophagic effect of centrally administered insulin in 3-mo-old male progeny. METHODS: Throughout pregnancy and lactation, Wistar rats ate isocaloric/normolipidic diets with soybean oil (control) or soybean oil-derived hydrogenated fat (trans diet) as a fat source. Upon weaning, the trans offspring continued on the trans diet (trans group) or were switched to a control diet (trans-control group). RESULTS: Compared with control rats, trans rats had lower brain levels of eicosapentaenoic acid. Compared with trans rats, trans-control rats had increased levels of total polyunsaturated fatty acids and arachidonic acid and decreased levels of trans fatty acids, saturated fatty acids, and monounsaturated fatty acids. Insulin receptor and insulin receptor substrate-1 levels were significantly lower (44% and 38%, respectively) in trans than in control rats. In trans-control rats, insulin receptor was 26% lower (P < 0.05), whereas insulin receptor substrate-1 was 50% lower, than in control rats. Insulin decreased 24-h feeding in control (27%) and trans (38%) rats but failed to do so in trans-control rats. The latter group had increased serum glucose levels. CONCLUSIONS: The data suggest that the early (intrauterine/perinatal) exposure to hydrogenated fat rich in trans fatty acids programmed the hypothalamic feeding control mechanisms. As young adults, only trans-control animals showed loss of insulin-induced hypophagia, indicating that the mismatch between early and later nutritional environments was relevant. However, the trans group also showed signs of altered appetite signaling mechanisms, suggesting that the early adaptations may have deleterious consequences later in life.     

Fatty acid composition of sweet bakery goods and chocolate products and evaluation of overall nutritional quality in relation to the food label information

The study aimed to determine fatty acid (FA) composition of some sweet bakery goods and chocolate products on Turkey market (n = 35) and to evaluate their overall nutritional quality in relation with the nutritional facts on the label. Moreover,“trans fatty acid (TFA)-free” declaration on the label was checked with the current labelling regulations in Turkey. Majority of the sample groups represented the prevalence of palmitic and oleic acid; on the other hand, it was difficult to specify a sample group with a specific FA. Erucic acid, for which European Commission set maximum limits, was not detected in any of the samples. It was observed that total saturated fatty acids (SFA) constituted more than 44 % of total FA. In all cases, total TFA content was lower than 1 % of total FA. Based on nutritional facts on the label, that type of products provide higher energy with the main source of fat and carbohydrates. Therefore, consumption of those products in a diet should be limited not to gain an excess amount of body weight and to have adverse health effects related to higher SFA content. This study can be regarded as a case surveillance study by providing updated data that can be used by Nutritionals and authorities to make risk assessments on consumer health.     

Fatty acid composition of Greek margarines and their change in fatty acid content over the past decades

Thirty-one brands of margarines from the Greek market were analyzed for their fatty acid composition including trans-fatty acids by gas chromatography. Trans fatty acids (TFAs) were found within the range of 0.16-0.97% of total fat content, with no sample found to have TFA in a concentration more than 1% of the total fat content. Increased levels of either saturated or cis-unsaturated was observed in each brand. Saturated, cis-monounsaturated and cis-polyunsaturated were found in the ranges of 11.26-51.75%, 22.98-60.37% and 12.09-56.30% of total fat content respectively, with mean values of 30.81 ± 10.40%, 34.41 ± 10.46% and 34.28 ± 14.02% of total fat. The chemical analysis of Greek margarines over the past decades has indicated that the TFA content of Greek margarines has declined over the past 20 years by approximately 95%.     

Variability in the trans fatty acid content of foods within a food category: implications for estimation of dietary trans fatty acid intakes.

OBJECTIVE: Currently, the published information on trans fatty acid composition of foods is incomplete and of questionable accuracy. Detailed fatty acid analysis of over 200 foods was undertaken for the purpose of determining the variability in trans fatty acid content among foods within a product category, and the significance of this variability to the estimation of trans fatty acids intakes from analysis of dietary intake data. METHODS: The analysis of food fatty acids used gas-liquid chromatography with 100 m capillary columns and standardized methodologies for food sampling, fat extraction, separation and quantification of trans fatty acid isomers. For the purposes of this report, trans refers to all non-naturally occurring isomers including trans, cis-trans, geometric and positional isomers. RESULTS: The results show that the amount of trans fatty acids varies considerably among foods within a category, reflecting differences in the fats and oils used in the manufacturing or preparation process. For example, the range of trans fatty acids in 17 brands of crackers was 23 to 51% total fatty acids, representing differences of from 1 to 13 g trans fatty acids per 100 g cracker. The large errors that may arise in estimates of the trans fatty acid intake of an individual are illustrated by analyses of the potential trans fatty acid intake in a sample diet, for each food as calculated using the minimum and maximum values for trans fatty acids within a given category. The results of these analyses show estimates of trans fatty acid intake from a low of 1.4 to 25.4 g a day for the same diet. CONCLUSION: This study shows that the wide variability in trans fatty acid content of different foods may result in large errors in the estimation of trans fatty acid intake of individuals and, potentially, groups.     

Analysis of Fat Content with Special Emphasis on Trans Isomers in Frequently Consumed Food Products in Egypt: The First Steps in the Trans Fatty Acid Elimination Roadmap

Trans Fatty Acid (TFA) intake is a risk factor for coronary heart diseases and cancer. Egypt, considered among the highest TFA consumers in the world, lacks proper dietary analysis of TFAs. This cross-sectional study aimed to analyze TFAs in traditional and frequently consumed food products. A market survey was conducted to identify products and brands that are mostly consumed in major governorates in Egypt. Laboratory analysis allowed for the profiling of TFAs, and saturated and unsaturated fatty acids. Products having more than 2 g of TFA/100 g of fat were considered to have an elevated TFA content. Commonly consumed food items (n = 208) in the Egyptian market were identified. On average, 34% of the products exceeded the TFA limit. Sambosk meat, a traditional meat item, had the highest TFA content of 5.2%, followed by foods fried with used oils. Oriental sweets had a TFA content three times higher than that of doughnuts. The fast-food group had the largest proportion of TFA-rich products, followed by the canned and frozen item groups and confectionaries. This study revealed that around one third of products in the Egyptian market have a high TFA content. This calls for urgent legislative action to regulate composition.     

Role of trans fatty acids in health and challenges to their reduction in Indian foods

Evidence indicates that dietary trans fatty acids (TFA) obtained from partially hydrogenated vegetable oils (PHVO) increase the risk of coronary heart disease (CHD). Studies have implicated TFA in increasing the risk and incidence of diabetes. Furthermore, TFA may compromise fetal and early infant growth and development. In rats, partial substitution of either linoleic acid (18:2 n-6) with saturated fatty acids (SFA, 6 en %) or SFA with TFA (3 en % from vanaspati) decreased peripheral insulin sensitivity, but these effects were greater in TFA group. Since a large proportion of Indian population is insulin resistant, the TFA content in Indian edible fats/oils and foods should be reduced. Vanaspati (PHVO) provides up to 40% TFA, is used in Indian cooking and in the preparation of commercially fried, processed, bakery, ready-to-eat and street foods. TFA in biscuits and sweets range 30-40 and 6-26% of total fatty acids respectively. There is no regulation on TFA content in vanaspati, bakery fats and shortenings. Reduction in Indian edible fats/ oils and foods can be achieved by: a) specifying limits of TFA in vanaspati, bakery fats and shortenings by upgrading technology; b) advocating the substitution of natural plant oils containing lower percent of polyunsaturated fatty acids for PHVO. Indian edible oil industry needs to develop and adopt alternative technologies to produce zero TFA. Consumer education about negative health effects of TFA and providing food based guidelines to reduce TFA consumption in the entire population need to be actively pursued.     

傅立叶变换红外光谱法分析食品及油脂中反式脂肪酸

目的：采用傅立叶变换红外光谱法定性定量分析食品及油脂中反式脂肪酸含量。方法：食品中提取的脂肪或油脂样品直接置于红外光谱仪的水平衰减全反射（HATR）部件的槽式ZnSe晶体上,氘化三甘氨酸硫酸酯（DTGS）检测器检测。通过966 cm-1处反式双键的特征峰进行定性,由峰面积与反式脂肪酸含量的线性校准曲线定量计算反式脂肪酸在油脂中的百分含量。结果：该方法可通过反式双键的特征峰对样品油脂中的反式脂肪酸进行准确定量。结论：此方法具有简单、快速、准确的特点,适用于食品营养标签的测定。     

Trans fatty acids in human milk lipids: influence of maternal diet and weight loss

Geometric and positional isomers of octadecanoic acid in milk expressed during the first 9 weeks of lactation were determined for mothers delivering prematurely (PT) and at term (FT). Total C18:1 concentration was lower in PT than FT milk. C18:1 trans (elaidic acid) content was higher in PT and FT colostrum compared with subsequent milk samples. No relationship was observed between C18:1 trans level in milk and oleic acid, linoleic acid, total fatty acid levels, or volume of milk expressed. While gestational age and lactational stage appeared to affect the trans fatty acid pattern, the overriding influence was rate of maternal postpartum weight loss. Effect of weight loss on milk trans fatty acid levels was independent of maternal diet. Trans fatty acid content of milk as a function of recent maternal fat intake was also demonstrated. This study indicates that infants receiving human milk ingest levels of trans fatty acids reflecting short and long term maternal diet.     

The importance of essential fatty acids and the effect of trans fatty acids in human milk on fetal and neonatal development

Breastfeeding has a major impact on public health, since human breast milk is the best food for infants up to six months of age. The lipid fraction in human milk is the main source of energy for the infant and supplies essential nutrients such as fat-soluble vitamins and polyunsaturated fatty acids (PUFA). Essential fatty acids (EFA), specifically linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3), are precursors of long-chain polyunsaturated fatty acids (LC-PUFA), including docosahexaenoic (DHA) and arachidonic (ARA) acids. Quality of lipids in secreted milk is precisely related to maternal ingestion. LC-PUFAs protect against allergy and infection and are important for visual and cognitive development in infancy. Industrial food processing has introduced the trans fatty acids (TFA) among the nutrients available to the population. TFA can interfere with the metabolism of essential fatty acids by decreasing LC-PUFA synthesis. It is thus important to raise population awareness on the importance of adequate PUFA consumption and reduced TFA intake during prenatal and postnatal development.