Proportion Of Dietary Fat Research Articles

Gastric bypass reduces fat intake and preference

Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation.

Cardiovascular Disease Risk Factors in Adolescent British South Asians and Whites: A Pilot Study

Background: Cardiovascular disease (CVD) and associated mortality are more common in British South Asians than in the British white population. Most of the aspects of the cardiovascular risk profile are modifiable, and are thought to be established in childhood. However, the role of genetics and ethnicity has not been fully elucidated. Objectives: This pilot study compared cardiovascular risk profiles in British South Asian and British white adolescents, and investigated the relationships between physical activity, cardiorespiratory fitness, nutrition, and CVD risk profile in both ethnic groups. Methods: Cardiovascular risk factors included systolic and diastolic blood pressure, body composition, fasting glucose, cholesterol, and triglycerides. Physical activity was measured using 7-day accelerometry; diet was measured from a 3-day dietary record. Fitness was assessed from running economy, submaximal exercise lactate response, and peak oxygen uptake. Body composition was determined through a bioelectrical impedance analyzer (BIA). Finger-prick blood samples were taken for fasting glucose, cholesterol, and triglycerides. Results: Twelve British South Asian males (aged 15.2 ± 0.3 years) and 11 British white males (aged 15.1 ± 0.3 years) were recruited. Mean systolic blood pressure in British South Asian adolescents was 6.9 mm Hg higher (95% confidence interval [CI], −13.4 to 0.4 mm Hg) than in their British white counterparts. Following multifactorial adjustment, this increased to 12.4 mm Hg. Fasting blood triglycerides were 1.04 mmol/L (0.52-1.57 mmol/L) higher in Asians; this was nonsignificant following adjustment for dietary factors. The British South Asian adolescents' diet contained 42 g (23-61 g) more fat per day. Conclusions: Differences in cardiovascular risk profile between British South Asian and British white males are present in adolescence, with higher fasting blood triglycerides in British South Asian adolescent males being attributed to a higher proportion of dietary fat. Interventions may thus be developed to influence dietary choices during childhood, and therefore potentially reduce CVD in adulthood.

Price Changes Alone Are Not Adequate to Produce Long-Term Dietary Change

Taxation has been proposed as a means to reduce consumption of unhealthy food items. However, it is unknown if taxation without regulations or other activities known to shift eating behaviors lead to long-term dietary change. This unexplored issue is examined using data from the Russia Longitudinal Monitoring Survey. Data were from adults aged 25–55 y who participated in the nationally representative Russian Longitudinal Monitoring Survey. Twenty-four–hour dietary recalls, detailed food expenditure data, and community-level food prices collected over 1994–2005 were used for these analyses. Longitudinal random effects models were used to test the relation of time on the structure of diet while controlling for total household expenditures. The proportion of total energy consumed from fat was higher in all other years combined compared with 1998 (P < 0.001). The proportion of dietary fat from high-fat meat and high-fat dairy items were lowest in 1998 and increased over subsequent years despite increasing costs. Percent fat from fats and oils continued to decline with rising costs. Price changes led to substantial shifts in the structure of food consumption. However, except for the most expensive items, consumption of items returned to levels consumed in the former Soviet Union following price stabilization.

Is Dietary Fat “Fattening”? A Comprehensive Research Synthesis

The goal of this research synthesis was to separate and articulate questions that had clear meaning, were empirically addressable, and were germane to the broad question “Is fat fattening?” Four such questions addressing the effect of varying the proportion of dietary fat on body weight and body fat were formulated. A comprehensive review of electronic citation databases was conducted to identify studies that addressed each question. The results of the studies addressing each question were tabulated and summarized, and an answer for each question was formulated. The results indicated that whether “fat is fattening” depends on exactly what one means by the question. It is apparent that under conditions of energy deficit, high-fat diets lead to greater weight loss than low-fat diets, but under ad libitum feeding conditions, instructing persons to follow a low-fat diet promotes loss of body weight and body fat. For one question, studies were few but convincing that altering the proportion of energy from fat in daily snacks has no effect on weight, while for another there were not enough studies available to answer the question with confidence. General recommendations to reduce dietary fat to promote weight loss or maintenance in all circumstances may merit reconsideration.

Differential Effects of Restricted Versus Unlimited High‐Fat Feeding in Rats on Fat Mass, Plasma Hormones and Brain Appetite Regulators

The rapid rise in obesity has been linked to altered food consumption patterns. There is increasing evidence that, in addition to total energy intake, the macronutrient composition of the diet may influence the development of obesity. The present study aimed to examine the impact of high dietary fat content, under both isocaloric and hypercaloric conditions, compared with a low fat diet, on adiposity, glucose and lipid metabolism, and brain appetite regulators in rats. Male Sprague-Dawley rats were exposed to one of three diets: control (14% fat), ad lib high-fat palatable (HFD, 35% fat) or high-fat palatable restricted (HFD-R, matched to the energy intake of control) and were killed in the fasting state 11 weeks later. Body weight was increased by 28% in unrestricted HFD fed rats, with an almost tripling of caloric intake and fat mass (P < 0.001) and double the plasma triglycerides of controls. Glucose intolerance and increased insulin levels were observed. HFD-R animals calorie matched to control had double their fat mass, plasma insulin and triglycerides (P < 0.05). Only ad lib consumption of the HFD increased the hypothalamic mRNA expression of the appetite-regulating peptides, neuropeptide Y and pro-opiomelanocortin. Although restricted consumption of palatable HFD had no significant impact on hypothalamic appetite regulators or body weight, it increased adiposity and circulating triglycerides, suggesting that the proportion of dietary fat, independent of caloric intake, affects fat deposition and the metabolic profile.

Erythrocyte Membrane Phospholipid Composition as a Biomarker of Dietary Fat

Background/Aims: In a cross-sectional study, we investigated the relationship between erythrocyte membrane phospholipid fatty acid composition and dietary fat; we also investigated roles of menopausal status, age, body mass index (BMI) and waist-to-hip ratio (WHR) in interindividual variation of the biomarker. Methods: Study participants were 204 women, aged 39–65 years, drawn from the ORDET cohort and selected as controls in a study of breast cancer. Membrane composition was assessed using capillary gas chromatography. Dietary fat composition was evaluated using a food frequency questionnaire. Results: In pre- and postmenopausal women, erythrocyte membrane phospholipid levels of linoleic acid, oleic acid, and mono-unsaturated fatty acids were significantly associated with corresponding dietary measures (partial correlation coefficients: 0.23 and 0.39; 0.45 and 0.47; 0.40 and 0.48; respectively, in pre- and postmenopausal women). Among postmenopausal women, membrane poly-unsaturated fatty acids were correlated with the corresponding dietary measure (r = 0.39, p < 0.001). Membrane eicosapentanoic and docosahexanoic acid levels were significantly correlated with intake of fish/shell fish : r = 0.21 and r = 0.43 (premenopausal), and r = 0.41 and r = 0.44 (postmenopausal). Age, BMI and WHR had independent effects on membrane lipid composition. Age was associated with delta-6 desaturase activity in postmenopausal women (r = 0.25, p < 0.05). BMI was negatively associated with delta-9 desaturase activity in both pre- and postmenopausal women (r = –0.29, p = 0.01 and r = –0.22, p < 0.01, respectively). WHR was negatively associated with delta-5 desaturase activity in pre-menopausal women (r = –024, p < 0.05). Conclusions: Erythrocyte membrane levels of some specific fatty acids can be used as biomarkers of these fatty acids as proportions of dietary fat.

Th-W55:2 Optimal proportions of dietary fat, protein, and carbohydrate for cardiovascular health

Th-W55:2 Optimal proportions of dietary fat, protein, and carbohydrate for cardiovascular health

Postmenopausal breast cancer is associated with high intakes of omega6 fatty acids (Sweden).

To estimate the postmenopausal breast cancer risk associated with total fat intake, different types and relative proportions of dietary fat using a nested, matched case-control study within the Malmö Diet and Cancer (MDC) cohort, Sweden. Among women 50 years or older at baseline (n = 12,803), incident breast cancer cases (n = 237) were matched to controls (n = 673) on age and screening date. Data were obtained by a "novel" diet history method, a structured questionnaire, and anthropometric measurements. Conditional logistic regression examined breast cancer risks associated with quintiles of fat intake residuals adjusted for energy and potential confounders. Saturated fat and the omega3-omega6 fatty acid ratio were not related to increased risks, but positive trends were seen for total (p = 0.031), monounsaturated (p = 0.002), and polyunsaturated fat (p = 0.0009), especially omega6 fatty acids and the polyunsaturated-saturated fat ratio (p = 0.004). With mutual adjustment for different types of fat, an elevated risk remained significant in the highest omega6 fatty acid quintile (RR= 2.08, 95% CI 1.08-4.01). Postmenopausal breast cancer was positively associated with total, monounsaturated, and polyunsaturated fat. However, with mutual adjustment for other types of fat, specifically high intakes of omega6 fatty acids were associated with an increased risk.

Effect of dietary α-linolenic acid on thrombotic risk factors in vegetarian men

Vegetarians have lower platelet and plasma concentrations of n-3 polyunsaturated fatty acids (PUFAs) than do omnivores. We recently showed that male vegetarians have higher platelet aggregability than do omnivores. We investigated whether male vegetarians (n = 17) who consumed an increased amount of dietary alpha-linolenic acid (ALA) showed any changes in their tissue profile of PUFAs, plasma thromboxane concentrations, platelet aggregability, or hemostatic factors. During the study, all subjects maintained their habitual vegetarian diets except that a proportion of dietary fat was replaced with vegetable oils and margarines that were provided. Initially, all subjects consumed a low-ALA diet (containing safflower oil and safflower oil-based margarine) for 14 d; they then consumed either a moderate-ALA diet (containing canola oil and canola oil-based margarine) or a high-ALA diet (containing linseed oil and linseed oil-based margarine) for 28 d. Blood samples were collected at day 0 (baseline), day 14, and day 42. Eicosapentaenoic acid, docosapentaenoic acid, total n-3 PUFAs, and the ratio of n-3 to n-6 PUFAs were significantly increased (P < 0.05), whereas the ratio of arachidonic acid to eicosapentaenoic acid was decreased (P < 0.05), in platelet phospholipids, plasma phospholipids, and triacylglycerols after either the moderate-ALA or high-ALA diet compared with the low-ALA diet. No significant differences were observed in thrombotic risk factors. ALA from vegetable oils (canola and linseed) has a beneficial effect on n-3 PUFA concentrations of platelet phospholipids and plasma lipids in vegetarian males.

Fatty Fish and Defatted Fish Products for Male Mink (Mustela vison) in the Growing-Furring Period: I. Effects on growth and pelt characteristics

Investigations on the use of fatty herring (Clupea harengus) scrap and mackerel (Scomber scombrus) (whole and scrap), and defatted herring scrap for male mink kits in the growing-furring periods were carried out in two consecutive years. Each year, three diets containing fatty herring scrap and three diets containing fatty mackerel, supplying 30, 50 or 70% of the dietary fat were compared with a control diet supplying only 20% of dietary fat as marine fat. In one of the experiments, another three groups were fed 12, 23 or 32% of defatted herring scrap in the diet. Each experimental group consisted of ∼75 male Scanglow mink kits. The energy content of the feed was 8.5 MJ kg-1 and there was ∼360 g crude protein per kg dry matter in all diets. When supplying up to a level of 50% of the fat from marine fat, the same or better weight gain, pelt length and fur quality in male mink kits were found compared with the control group. Increasing the proportion of dietary fat from herring scrap or mackerel up to 70% reduced both pelt length and fur quality compared with inclusion of 50% marine fat. Defatted herring scrap resulted in good pelt length and fur quality compared with the control group when used in proportions up to 32% of the diet, and the product is a good alternative feedstuff for mink feed.

Intestinal Worm Burden and Serum Cholesterol or Lipid Concentration in a Shipibo Population (Peru)

Paired samples of stool and serum of 32 members of the Shipibo tribe resident in the rain forest of the Peruvian lowlands were tested for worm egg count and serum lipid parameters, respectively. 90% of the stool samples tested were found to contain eggs or larvae of several worm species, most commonly 3 or 4 different species. Serum lipid levels were found to be relatively low, most probably due to a low proportion of dietary fat ranging from 16-31%. Statistical analysis showed a significant inverse correlation between worm egg excretion and HDL levels which was true for hookworm, strongyloides and trichuris, but not for ascaris. The mechanisms underlying the observed association between intestinal worm load and HDL reduction are not completely understood and may include reduced HDL synthesis in the gut wall due to inflammatory and/or toxic irritation.

Educational attainment and nutrient consumption patterns: The Minnesota Heart Survey

To explore whether dietary patterns differ according to educational attainment, we examined the associations of nutrient intake with educational level in a sample of 825 male and 893 female Twin Cities (Minneapolis and St. Paul) residents aged 25 to 74 years who were surveyed between 1980 and 1982. Of particular interest was the pattern of macronutrient consumption, since the proportion of fat and type of fat in the diet is thought to be related to the development of chronic disease. Estimates of nutrient intake were based on 24-hour dietary recalls, while information on education was obtained through interview. Educational attainment was positively associated with nutrient consumption patterns that may decrease risk of chronic disease for both men and women. For women, the proportion of dietary fat was less (p=.03) and carbohydrate greater (p=.004) with increasing education. For men, the Keys dietary score decreased as education increased (p=.05) (high scores indicate greater blood cholesterol-raising effect of the diet). Inverse associations of average total serum cholesterol level with education in both men (p=.02) and women (p=.06) support these dietary associations. These results suggest that educational attainment is related positively to eating patterns that may carry a decreased risk of cardiovascular and other chronic disease. Whether or not this association is causal, it would appear to point to a need for more effective nutrition education strategies for those with less education. J Am Diet Assoc 88:1230, 1988.

Effects of ethanol diets on cholesterol content and phospholipid acyl composition of rat hepatocytes.

Chronic treatment of adult male rats with ethanol liquid diets resulted in alterations in phospholipid and cholesterol contents as well as the acyl composition of phosphatidylethanolamine (PE), phosphatidylinositol (PI)-phosphatidylserine (PS) mixture, and phosphatidylcholine (PC) of isolated hepatocytes. The influence of ethanol on these lipids was largely dependent on the proportion of dietary fat. Phospholipid and total cholesterol contents were elevated 23 and 27%, respectively, by ethanol when offered in a low-fat diet (5% corn oil). Only the percentage of arachidonic acid from PI-PS was significantly reduced in the low-fat ethanol group. Exposure to a high-fat (34% corn oil) diet in the presence of ethanol for 4-5 weeks resulted in a significant decrease in arachidonate/linoleate ratios of hepatic PE, PS-PI and PC, while total phospholipid content remained constant. In the high-fat, ethanol-treated group, hepatic cholesterol content was increased 2-fold. These results suggest that the level of dietary fat plays an important role in determining the effects of chronic ethanol consumption on hepatic cholesterol content and phospholipid acyl composition.

Ethanol—A direct inducer of drug metabolism

The inductive effects of chronic phenobarbital and ethanol ingestion on hepatic microsomal drug metabolism were examined in rats consuming different proportions of dietary fat. Eight groups of rats were fed for 1 week on matched amounts of nutritionally adequate liquid diets providing 2, 5, 10 or 41% of calories as fat (safflower oil), two groups at each level. One group at each level received phenobarbital (80 mg/kg daily by intubation), the other getting water. In a parallel experiment, one group at each fat level received 36% of calories as ethanol, the other as sucrose, and these regimens were continued for 1 month. Dietary fat content per se had no significant effect on body weight, liver weight, microsomal protein, cytochrome P-450 content, or hepatic triglycerides (TG) during the 1-week experiment, but significantly increased all these measures in the 1-month experiment. Both phenobarbital and ethanol treatment increased all these measures except body weight, but phenobarbital had a greater effect on liver weight, microsomal protein and cytochrome P-450, while ethanol had a greater effect on hepatic TG and a significant interaction with dietary fat content in relation to TG levels. In contrast, microsomal metabolism of aminopyrine, aniline and meprobamate in vitro was increased approximately equally by phenobarbital and ethanol, while dietary fat content had no effect alone, and no significant interaction with phenobarbital or ethanol. Ethanol, like phenobarbital, therefore, appears to induce microsomal drug metabolism independently of its effects on TG metabolism.

Nutrition in Relation to Cancer

Publisher Summary When living cells are subjected to carcinogenic influences, they may undergo changes that result in a growing neoplasm. The energy and substance for the development of the first cancer cells are principally derived from the animal; the new cell type increases in number by assimilating nutrients from the host. The diet and the nutritional state of the host influence the formation and growth of tumors. This chapter discusses some general and methodological considerations that may facilitate an understanding of the nutrition-related problems in context of cancer. The chapter emphasizes the influence of diet on the genesis and growth of neoplasms and discusses the significance of the level of caloric intake and the proportions of dietary fat, protein, vitamins, and minerals. Investigations on the action of crude materials and extracts are not included because exact compositions and effective components are generally not known. The chapter reviews the studies suggesting that nutrition plays a role in the formation of cancer in man.