Isomeric trans fatty acids in the U.S. diet

Since actual consumption data for trans fatty acid (FA) intakes for the U.S. population do not exist, estimates of trans fatty acids (FAs) available in the U.S. food supply have been calculated from U.S. Department of Agriculture-Economic Research Service (USDA-ERS) fats and oils production figures and food disappearance data for fats and oils. Based on weighted averages for the trans levels in each fats and oils category, these estimates of trans FAs available in the U.S. food supply range from 12.5 to 15.2 g/person/day (average 13.3 +/- 1.1 g/person/day). Estimates of trans FA consumption have been calculated; these estimates predict a wide range from 1.6 to 38.7 g/person/day. These calculations are based on published estimates of trans FAs available in the total fat of 5-15%, and the total fat intake (range 31-258 g/person/day) of a representative sample of adults (ages 20-59) as determined by the Lipid Research Clinics (LRC). Using an equation based on a relationship between trans FAs in adipose tissue and dietary fat, an intake range of 0.7-28.7 g/person/day trans FAs for the same LRC fat consumption data can be predicted. Adipose tissue isomer profiles that indicate 90-95% of the trans FAs in the tissues comes from partially hydrogenated vegetable fats and oils allow us to predict a dietary intake range from 11.1 to 27.6 g/person/day trans FAs. The significance of these estimates to nutrition policy is discussed.     

Isomeric trans fatty acids in the U.S. diet.

Since actual consumption data for trans fatty acid (FA) intakes for the U.S. population do not exist, estimates of trans fatty acids (FAs) available in the U.S. food supply have been calculated from U.S. Department of Agriculture-Economic Research Service (USDA-ERS) fats and oils production figures and food disappearance data for fats and oils. Based on weighted averages for the trans levels in each fats and oils category, these estimates of trans FAs available in the U.S. food supply range from 12.5 to 15.2 g/person/day (average 13.3 +/- 1.1 g/person/day). Estimates of trans FA consumption have been calculated; these estimates predict a wide range from 1.6 to 38.7 g/person/day. These calculations are based on published estimates of trans FAs available in the total fat of 5-15%, and the total fat intake (range 31-258 g/person/day) of a representative sample of adults (ages 20-59) as determined by the Lipid Research Clinics (LRC). Using an equation based on a relationship between trans FAs in adipose tissue and dietary fat, an intake range of 0.7-28.7 g/person/day trans FAs for the same LRC fat consumption data can be predicted. Adipose tissue isomer profiles that indicate 90-95% of the trans FAs in the tissues comes from partially hydrogenated vegetable fats and oils allow us to predict a dietary intake range from 11.1 to 27.6 g/person/day trans FAs. The significance of these estimates to nutrition policy is discussed.     

2006 marketplace survey of trans-fatty acid content of margarines and butters, cookies and snack cakes, and savory snacks

In recent years, newer technologies have been developed to reduce the trans-fat content of fats and oils used in manufacturing food products. To examine the implications of these changes on foods in the marketplace, a survey was conducted to assess current levels of trans and saturated fat in three food categories: margarines and butters; cookies and snack cakes; and savory snacks. A sampling of products from each category was conducted at a Wal-Mart Supercenter in the Minneapolis-St Paul, MN, metropolitan area in July of 2006. All information was obtained from product labels, except price, which was recorded from price listings on product shelving. Most margarines and butters (21 of 29), cookies and snack cakes (34 of 44), and savory snacks (31 of 40) were labeled as containing 0 g trans fat. However, some products contained substantial amounts of trans fat. Most notably, 3 of 40 savory snack products were labeled as containing > or =3 g trans fat. Significant inverse correlations were found between product price and the saturated and trans-fat content of margarines (r=-0.45) and savory snacks (r=-0.32). In conclusion, it appears that the food industry has made progress in reducing the trans-fat content in a variety of products. Nonetheless, consumers need to read product labels because the trans-fat content of individual products can vary considerably. Products that are lower in trans and saturated fat tend to cost more, which may be a barrier to their purchase for price-conscious consumers.     

Stages of Change and Reduction of Dietary Fat: Effect of Knowledge and Attitudes in an Australian University Population

This survey focused on the use of the stages of change model of behavior change in reducing dietary fat intake while identifying attitudinal variables that might be relevant in the decision to change one's dietary habits. Knowledge of dietary fat and reported fat intake were also examined. Data were obtained using a cross-sectional survey of 1081 university employees. The Precontemplation stage comprised the largest group of respondents (33%) while the Contemplation stage was the smallest group, containing only 6% of respondents. Twelve percent of respondents were in the Preparation stage while the Action and Maintenance groups comprised 22% and 27% of the total population, respectively. Two one-way multivariate analyses of variance were used to compare male and female respondents across the five stages of change on knowledge, dietary fat intake, benefits, and barriers. Dietary fat intake and barriers to reducing fat intake decreased significantly across the stages of change while the benefits to change increased significantly across the stages. The results of our study confirm differences in stages of change in fat intake and indicate the need for taking these phases of change into account in nutrition advice.     

Long-term maintenance of a low-fat diet: durability of fat-related dietary habits in the Women's Health Trial.

The Women's Health Trial (WHT) was a feasibility study for a randomized trial of a low-fat diet for the prevention of breast cancer. One year after the WHT was terminated, a random sample of 894 participants who had been active in the WHT for an average of 16 months (range = 5 to 37) completed questionnaires about their dietary habits (a 21-item instrument that measures five dimensions of low-fat dietary habits) and food intake (a food frequency questionnaire). Women who participated in the intervention program maintained most of the low-fat dietary habits adopted during the study: mean total fat intake increased from 37.8 g to 41.0 g and scales describing substitution of specially manufactured low-fat foods and modification of meats to be lower in fat increased only slightly (by 0.11 and 0.14, respectively, on a scale of 1 = always to 4 = never). Scales describing avoiding meat and avoiding fats as a flavoring increased by 0.23 and 0.22, respectively, which suggests some recidivism. Women in the control group lowered their dietary fat intake from 65.0 to 57.5 g, but all differences in fat intake and fat-related dietary habits scales between women in the control and intervention groups remained highly statistically significant. In multiple regression models, all five low-fat dietary habits scales were independently associated with percentage of energy from fat, but the strongest association was for avoiding fats as flavorings. These results suggest that substitutions of specially manufactured low-fat foods are easily adopted and maintained dietary changes, but that maintenance of new habits related to avoiding fats as flavorings and avoiding meat will require long-term reinforcement strategies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Are awareness of dietary fat intake and actual fat consumption associated?--a Dutch-American comparison

OBJECTIVES: To compare dietary fat intake, the accuracy of individuals' awareness about their fat intake, and sociodemographic and psychosocial correlates of awareness, in Dutch and American samples of employed adults. A discrepancy between objective dietary intake data and subjective self-evaluation of dietary fat consumption has been recognized in the past and might undermine healthy diet promotion interventions, and this is important because people who believe that their diets are healthful are less likely to be interested in making changes. Further, international comparisons have not been examined to date. DESIGN: Data collected for the baseline surveys of the 'Healthy Bergeijk' study in the Netherlands and the 'Working Well Trial' in the United States were compared. SUBJECTS: Working adults from a Dutch community health intervention study (n = 768) and an American worksite health promotion trial (n = 15,440). MAIN OUTCOME MEASURES: Objectively assessed dietary fat intake, measured by food frequency questionnaires, and subjective ratings of fat intake (self-rated fat intake). RESULTS: Findings show that the Dutch respondents had higher objectively assessed fat intake and lower subjective ratings of fat intake (P < 0.001). American respondents perceived their diets as higher in fat, more often stated their intentions to reduce fat intake, and were slightly more likely to make realistic estimates of their dietary fat. Dutch subjects were significantly more likely to underestimate their fat intakes. In both samples, women were most likely to underestimate their fat consumption and the most educated persons were most likely to be realistic. CONCLUSIONS: A substantial proportion of adults, both in the United States and the Netherlands, lack accurate awareness about how much fat they consume, though errors tend to be in opposite directions in the two countries. This study is an important first step toward broadening our international understanding of human dietary behavior for disease prevention.     

Association of fruit and vegetable intake with dietary fat intake

We examined the relation of fruit and vegetable intake with dietary fat intake under conditions in which individuals consume recommended number of portions of dairy, meat and grain foods, using 24-hour dietary recall data from the NHANES II of 1976–80. Only recalls that included at least 2 servings each of dairy foods and meat and 4 servings of grains, but variable servings of fruits and vegetables (ranging from 0 to 2 or more) were examined, yielding a total of 9 food group patterns (possible combinations of food group servings) as reported by 1,490 respondents. In patterns ranging from 0 to 2 servings each of fruits and vegetables, the mean percent of energy as fat varied from 39% to 36%. We observed a slight trend for decreasing energy from fat with increasing number of fruit-but not vegetable-servings. Consumption of fruits and vegetables was not associated with selection of lower-fat foods in the meat, dairy or grain groups. The percent of daily fat contributed by the miscellaneous food group (containing visible fats, sweeteners, and baked products with a high fat or sugar content) increased with increasing vegetable-but not fruit-servings. These results suggest that without conscious effort to reduce fat intake, an increase in fruit and vegetable intake may have a relatively minor impact on reduction of dietary fat.     

Use of Trans Fat Information on Food Labels and Its Determinants in a Multiethnic College Student Population

ObjectivesTo examine the correlates of trans fat knowledge and trans fat label use; to examine the influence of trans fat knowledge, trans fat label use, and dietary attitudes on intake of high trans fat food.DesignCross-sectional survey.SettingAn urban commuter college.SubjectsTwo hundred twenty-two college students.Variables measuredTrans fat knowledge, food label use, high trans fat food consumption, dietary attitudes, and sociodemographic factors.AnalysisChi-square tests and multivariate logistic regression analysis assessed relationships between trans fat knowledge, trans fat label use, and consumption of high trans fat food.ResultsThirty-seven percent of participants reported never using trans fat information on food labels. Males and minority ethnic groups were less likely to report always using trans fat label information and displayed lower trans fat knowledge compared to females and non-Hispanic whites, respectively. Trans fat knowledge and importance of eating a low-fat diet were positively associated with both food label use and use of trans fat information on food labels. Nonuse of food labels and trans fat information on food labels were associated with higher consumption of fried food.Conclusions and ImplicationsTrans fat education and promotion of food label use is needed in college students, especially in high-risk groups such as males and ethnic minorities.     

Dietary fat reduction strategies used by a group of adults aged 50 years and older

OBJECTIVE: To investigate the fat-reduction strategies used by a group of older adults who successfully made and maintained positive dietary changes for 5 years or longer. DESIGN: Participants completed 2 copies of a self-administered food frequency questionaire: The first copy assessed diet before they began making changes and the second copy assessed diet after initiation of healthful dietary changes. Positive food changes were identified from the food frequency questionnaires. During in-person interviews, participants placed food changes onto a time line according to the nearest estimated date of initiation of the change. SUBJECTS: Participants were 65 free-living older adults (aged >50 years) who had maintained substantial changes to decrease fat intake in their diet for at least 5 years. Statistical analyses performed Quantitative and qualitative data were used to identify the fat-reduction strategies and to confirm and validate the fat-reduction strategy model. Confirmatory factor analysis was performed to confirm the new model. The Kuder-Richardson-20 reliability coefficient (kr) was used to determine internal consistency of the scales developed for the study. RESULTS: The majority of participants decreased their fat intake gradually, at different time points in their lives, and over a long period of time (5 to 43 years). Mean percent energy intake from fat decreased from 44.3 +/- 5.9% before dietary improvement to 25.9 +/- 7.1% at the time of the study. The final model consisted of 5 fat-reduction strategies with 63 food changes. The strategies were: increase summer fruits (4 items; kr=0.66), increase vegetables and grains (14 items; kr=0.79), decrease recreational foods (14 items; kr=0.76), decrease cooking fat (20 items; kr=0.86), and use fat-modified foods (11 items; kr=0.80). APPLICATIONS/CONCLUSIONS: Dietetics professionals should base their advice on the dietary strategies used by consumers rather than hypothetical premises such as food or nutrient groupings. Nutrition education interventions will have better chances for success if they are based on a set of customized programs that guide appropriate consumer segments through a series of small, comfortable, and sustainable dietary changes over a prolonged period of time.     

Use of Qualitative and Quantitative Methods to Define Behavioral Fat-Reduction Strategies and Their Relationship to Dietary Fat Reduction in the Patterns of Dietary Change Study

Objective The purposes of this study were to identify specific food choice behaviors used to decrease dietary fat intake in a community-dwelling population; assess how people categorize changes to diet; determine whether logical grouping of food intake changes revealed one or more common patterns or strategies used by these participants to decrease fat; and determine which strategies were responsible for the greatest decrease in dietary fat intake in the study population.

Design Survey analysis and in-depth interviews were used to quantitatively and qualitatively define dietary change patterns retrospectively in a population who, according to self-report, had decreased their fat intake. Specific food changes made to decrease fat intake, interview statements, and participants' reduction of percentage energy from fat were examined.

Setting Interviews were conducted from June 1993 through April 1994.

Subjects Included in the study were 145 persons aged 30 to 55 years who reported that they had been decreasing their dietary fat intake for 5 years or more, maintained a healthful diet for at least 5 months, and resided in the United States while changing their diets.

Statistical analyses performed Confirmatory factor analysis, reliability analysis, and linear regression analysis were performed.

Results Nine fat-reduction strategies were identified. Decrease fat flavorings, decrease “recreational foods,” decrease cooking fat, replace meat, change breakfast, and use fat-modified foods accounted for significant reduction in fat intake.

Conclusions People use a variety of dietary changes to reduce their fat intake. These changes can be categorized into strategies according to the way people change their diets. Knowledge of these strategies and their importance in dietary fat reduction can improve and help nutritionists prioritize the messages they convey. J Am Diet Assoc. 1996; 96:1245–1250,1253.     

Recommended dietary reference intakes, nutritional goals and dietary guidelines for fat and fatty acids: a systematic review

Dietary fat and its effects on health and disease has attracted interest for research and Public Health. Since the 1980s many bodies and organizations have published recommendations regarding fat intake. In this paper different sets of recommendations are analyzed following a systematic review process to examine dietary reference intakes, nutritional goals and dietary guidelines for fat and fatty acids. A literature search was conducted in relevant literature databases along a search for suitable grey literature reports. Documents were included if they reported information on either recommended intake levels or dietary reference values or nutritional objectives or dietary guidelines regarding fat and/or fatty acids and/or cholesterol intake or if reported background information on the process followed to produce the recommendations. There is no standard approach for deriving nutrient recommendations. Recommendations vary between countries regarding the levels of intake advised, the process followed to set the recommendations. Recommendations on fat intake share similar figures regarding total fat intake, saturated fats and trans fats. Many sets do not include a recommendation about cholesterol intake. Most recent documents provide advice regarding specific n-3 fatty acids. Despite efforts to develop evidence based nutrient recommendations and dietary guidelines that may contribute to enhance health, there are still many gaps in research. It would be desirable that all bodies concerned remain transparent about the development of dietary recommendations. In order to achieve this, the type of evidence selected to base the recommendations should be specified and ranked. Regular updates of such recommendations should be planned.     

Reported adoption of dietary fat and fiber recommendations among consumers

OBJECTIVE: To identify constraints in adopting dietary fat and fiber recommendations. DESIGN: A questionnaire was mailed to a sample of the general population, a convenience sample of persons with heart disease and cancer in 11 states, and registered dietitians in 5 states. The survey included questions on demographic and attitudinal factors that were correlated with specific practices to reduce fat intake and increase fiber intake. SETTING: From the general population sample of 6,206 eligible respondents (return rate of 51.5%), those selected were respondents who indicated that they would adopt a dietary recommendation if it were good for them (n = 2,682). Subsamples from the general population were matched to 362 registered dietitians and 147 persons with cancer or heart disease on selected demographic variables. Factors associated with adoption of specific behaviors were identified. STATISTICAL ANALYSIS PERFORMED: Statistical analysis included chi 2, factor analysis, and analysis of variance. RESULTS: The majority of persons who said they would adopt a fat-reducing behavior if it were good for their health reported practicing that behavior often or usually. More than 60% reported consuming whole grains; however, only 15% reported eating fruits and vegetables frequently. Among the general population sample, those more likely to practice a behavior had the following characteristics: female, college educated, older than 60 years, white, higher income, no children younger than 18 years, perceived health status as excellent, and absence of chronic disease. Registered dietitians and those with chronic disease were also more likely to follow dietary fat and fiber recommendations. APPLICATIONS: Nutrition education messages that lead to increased consumption of dietary fiber need to be developed. Nutrition educators should provide strategies for consumers for increasing use of fruits and vegetables in all meals. Good taste and convenience are critical components. The food industry may assist by providing a wider array of convenience entrees or side dishes that feature produce and whole grains.     

Animal Fat Intake Is Associated with Albuminuria in Patients with Non-Alcoholic Fatty Liver Disease and Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) are associated with chronic kidney disease (CKD). Diet could play a predisposing role in the development of increased albuminuria in patients with NAFLD and MetS; however, published evidence is still limited. The aim of this cross-sectional analysis was to assess whether dietary fats are associated with changes in urinary albumin-to-creatinine ratio (UACR) in 146 patients aged 40–60-years with NAFLD and MetS. Dietary data were collected by food frequency questionnaire; UACR was measured in a single first morning void. Sources and types of dietary fats used in the analysis were total fat, fats from animal and vegetable sources, saturated, monounsaturated, polyunsaturated, and trans fats. One-way analysis of variance was performed to assess differences in dietary fats intakes across stages of UACR. The association between dietary fats and UACR was assessed by Pearson’s correlation coefficient and multivariable linear regression. Patients with increased UACR showed a worse cardiometabolic profile and higher intakes of animal fat, as compared to patients with normal levels of albuminuria. Animal fat intake was associated with mean UACR, independent of potential covariates.     

Trans fatty acids– Metabolic and nutritional significance

'Trans' fatty acids are unsaturated acids with special structural features that occur naturally in dietary fats from animal and plant sources and in fats processed by catalytic hydrogenation. They are readily metabolized by the human body. Thus, although when consumed in the diet they are incorporated into body fat (including depot and milk fats), they are subject to rapid 'turnover'. In physical properties, trans monounsaturatedfatty acids are intermediate between cis-monounsaturated and saturated acids, and they tend to be treated either as saturated or cis-monounsaturated acids in metabolic pathways. The author argues in this article that any adverse effects on health or metabolism that may have been observed can be ascribed to an imbalance between the intake of trans and essential fatty acids. Such imbalances, could also occur with non-essential fatty acids other than trans fats. Normally, the amounts eaten in average diets would not pose serious problems and only when products have excessively high trans contents and make a significant contribution to the diet need trans acids be highlighted on labels.     

Consumer heterogeneity in sugar consumption with special reference to fat and cholesterol intake

Consumers make dietary choices based on information they have. This study examines consumer choice of food products considering the healthfulness of multiple nutrients. We focus on high levels of sugars because higher levels of intake are associated with adverse health and nutritional outcomes. We find an important association of sugar consumption with the healthfulness of a diet based on saturated fat intake and cholesterol intake. Consumers making healthier choices in one nutrient are not making healthier choices on other nutrients. Our results suggest that individuals who were making better dietary choices based on saturated fats were consuming more sugars. This could indicate challenges with the existing standard nutrition label as an information tool towards making healthful choices on multiple nutrients.     

The effects of individual milk-drinking habits on nutrient intake and dietary patterns in men and women in Tottori Prefecture

This study was performed to determine the actual conditions of milk-drinking habits in men and women, and to ascertain their effects on nutrient intake and dietary patterns. The 809 subjects were over 20 years of age and were obtained from the Tottori Prefecture Dietary Survey. The results are summarized as follows: 1. Over 40 percent of the subjects did not consume any milk during the three days of the dietary survey. Furthermore, only 38 percent of men and 46 percent of women have daily milk-drinking habits according to the results of the questionnaire. 2. Calcium and Vitamin B2 intake level and total serum cholesterol level were higher in milk-drinkers than non-milk-drinkers, in both men and women. The regression of total calcium intake from 6 groups of food was analyzed by multiple regression analysis. For both men and women who were milk-drinkers, total calcium intake was determined mostly by milk. In the case of non-milk-drinkers, total calcium intake came mostly from green vegetables for men, and other vegetables for women. 3. The ratios of both animal proteins and animal fats were higher in milk-drinkers. For women, energy percentage of fats was high and that of carbohydrates was low in milk-drinkers. The results seem to suggest that differences in dietary patterns is based on milk-drinking habits. Using the Hayashi's quantification method 3, dietary patterns were classified into two groups based on milk-drinking habits. Dietary patterns of milk-drinkers included the characteristic of eating bread, meats, and fats more frequently in men, fresh vegetables, eggs, fats and bread in women. In men, milk-drinking habits had a lesser influence on diet than in women.     

Promoting dietary change in adolescents: a school-based approach for modifying and maintaining healthful behavior

We examined the immediate and long-term effects of a school-based, behaviorally focused dietary change program for tenth-graders. Our behavioral change objectives included increased consumption of complex carbohydrates and decreased intake of saturated fats, sugar, and salt, particularly in the form of snack foods. We randomly assigned tenth-grade classes in two northern California high schools to either a five-session dietary change program or an assessment-only control group. We collected pre- and postprogram self-report data on 218 students in areas of dietary knowledge, behavior, attitudes, food availability in the home, and intentions and self-efficacy concerning eating in specific ways. We also observed school snack choices both directly and indirectly. Our results indicated significant changes in reported behavior, knowledge, and food availability at home, as well as changes in snack choices at school. We found these changes to be durable at one-year follow-up. Our findings suggest ways in which school-based programs focused on behavioral and environmental changes may be effective in promoting dietary changes at school and at home.     

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.     

The effects of dieting on food and nutrient intake of lactating women

The purpose of this report was to identify and evaluate dietary changes in women who were participating in a study on the effects of weight loss in overweight lactating women on the growth of their infants. Women were randomly assigned at 4 weeks postpartum to either restrict energy intake by 500 kcal/day (diet and exercise group) or to maintain usual dietary intake (control group) for 10 weeks. The diet and exercise group significantly decreased fats, sweetened drinks, sweets and desserts, snack foods, and energy intake. Micronutrient intake decreased in the diet and exercise group; however, mean intakes were not significantly different from those of the control group except for calcium and vitamin D. Both groups consumed less than 76% of the Recommended Dietary Allowance for vitamins E and C at the end of the study. Mean intake of all other nutrients was adequate in both groups. These results suggest that overweight lactating women can restrict their energy intake by 500 kcal per day by decreasing consumption of foods high in fat and simple sugars. However, they must be advised to increase their intakes of foods high in calcium and vitamin D. Increased intake of fruits and vegetables should also be recommended to all lactating women, as well as multivitamin and calcium supplements to those who do not consume adequate amounts of these foods.