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PubMed1995

Olive oil, other dietary fats, and the risk of breast cancer (Italy).

Data from a multicenter case-control study on breast cancer conducted in Italy have been used to analyze the relationship of olive oil and other dietary fats to breast cancer risk. Cases were 2,564 women hospitalized with histologically confirmed, incident breast cancer. Controls were 2,588 women admitted to the same network of hospitals for acute, non-neoplastic, non-hormone related, non-digestive tract disorders. Cases and controls were interviewed between 1991 and 1994 using a validated food-frequency questionnaire. The data were modelled through multiple logistic regression controlling for demographic and reproductive breast-cancer risk factors, energy intake and, mutually, for types of dietary fat. For olive oil, compared with the lowest quintile, the odds ratios (OR) were 1.05, 0.99, 0.93, and 0.87 for increasing quintiles of intake; in a model postulating linear logit increase, the OR per unit (30 g) was 0.89 (95 percent confidence interval [CI] = 0.81-0.99, P = 0.03). Among other oils or fats considered, the OR for the highest level of intake was 0.72 (CI = 0.6-0.9) for a group of specific seed oils (including safflower, maize, peanut, and soya) compared with nonusers. The ORs for the highest cf lowest level of intake were 0.80 for mixed or unspecified seed oils, 0.95 for butter, and 0.96 for margarine. The study, based on a large dataset from various Italian regions, shows an inverse relationship of breast cancer risk with intake of olive oil and other vegetable oils, but not with butter or margarine.

Adult↗

PubMed2004

Effect of dietary fat intake and exercise on inflammatory mediators of the immune system in sedentary men and women.

OBJECTIVE: Dietary fat intake and exercise affect the immune system. This study determined the changes in inflammatory components of the immune system in response to maximal exercise with three levels of dietary fat intake: 19%, 30%, and 50% of total calories. METHODS: Five men and six women were randomly assigned to consume diets with 19% and 50% calories from fat for three weeks each, with a one-week washout. The habitual and washout diets were 30% calories from fat. At the beginning and the end of each diet, body composition and maximal exercise tests were performed. Blood samples were collected before and after exercise to determine the immunological parameters. RESULTS: The subject's energy intake was balanced to expenditure on the 30% and 50% diets, but was in negative balance on the 19% diet. Exercise led to significant increases in the concentrations of leukocytes, neutrophils, lymphocytes, monocytes, plasma tumour necrosis factor (TNF)-alpha, plasma interleukin (IL)-2, plasma soluble vascular cell adhesion molecule (sVCAM)-1, and the production of IL-1beta and IL-6 by peripheral blood mononuclear (PBMN) cells stimulated with lipopolysaccharide (LPS), irrespective of diets (p < 0.05). The 19% fat diet resulted in increased plasma soluble intercellular adhesion molecule (sICAM)-1 after exercise. Leukotriene (LT) B4 concentration released by neutrophils stimulated with LPS was higher in the 50% fat diet, compared to the lower fat diets, and the sICAM-1 production of neutrophils stimulated with LPS was significantly increased after exercise only with 30% fat diet. CONCLUSION: While a short, intense bout of exercise increased pro-inflammatory mediators of the immune system, decreasing fat intake to 19% on a caloric deficient diet caused a greater increase in plasma TNF-alpha, sVCAM-1 and sICAM-1 concentration than the 30% and 50% fat diets in male and female subjects. Increasing fat calories to 50% with caloric balance did not exacerbate pro-inflammatory mediators compared to a 30% fat diet.

Adult↗

PubMed2003

Association of glutathione peroxidase activity with insulin resistance and dietary fat intake during normal pregnancy.

Glutathione peroxidase (GPx) is one of the most important antioxidant enzymes in humans. We studied the relationship between erythrocyte GPx activity and fasting serum insulin, plasma glucose, and C-peptide, estimates of insulin resistance from the homeostasis model of assessment as well as dietary fat intake in 408 normotensive nondiabetic pregnant women from Camden, NJ. GPx activity and the metabolic parameters were determined at entry to care (16 wk of pregnancy) and during the third trimester. GPx activity and the levels of insulin resistance increased significantly between entry and the third trimester. Statistically significant associations, all positive, were observed between GPx activity and fasting insulin (beta = 0.009, P < 0.001), glucose (beta = 0.975, P < 0.05), C-peptide (beta = 1.537, P < 0.01), and insulin resistance from the homeostasis model of assessment (beta = 0.209, P < 0.01). Dietary intakes of fat and polyunsaturated fatty acids were positively correlated with GPx activity as well. African Americans had significantly higher GPx activity, dietary fat, and polyunsaturated fatty acid intake than Hispanics and Caucasians. In conclusion, we demonstrated that normal pregnancy is associated with increased GPx activity and insulin resistance. There are ethnic differences in antioxidant response and dietary fat intake. Our findings suggest a potential link among antioxidant defenses, insulin resistance, and dietary fat intake.

Adult↗

PubMed1996

Effects of breeder hen age and dietary fat on embryonic and neonatal broiler serum lipids and glucose.

In two experiments, the effects of dietary fat and breeder hen age on relative yolk sac weight (RYSW) and total serum cholesterol (CHOL), high (HDLC) and low (LDLC) density lipoprotein cholesterol, triglycerides (TRI), and glucose (GLU) were monitored in broiler embryos and chicks. In Experiment 1, embryos at 18 d of incubation and chicks at hatch were sampled from eggs laid by breeder hens at 26 (young), 36, and 48 wk of age. No dietary effects were noted in either experiment; however, chicks from young hens exhibited elevated serum CHOL, HDLC, LDLC, and lower GLU when compared with chicks from hens at either 36 or 48 wk of age. Additionally, embryos from young breeders displayed a lower RYSW at 18 d of incubation. Conversely, by hatch there was no difference in RYSW among offspring from different aged hens. In Experiment 2, newly hatched chicks were sampled from breeder hens at 36, 51, and 64 wk of age. Dietary effects were also not evident in this experiment; however, chicks from 51-wk-old breeders displayed the highest and lowest serum HDLC and TRI, respectively, compared to the other two age groups, whereas chicks from either 51- or 64-wk-old breeders exhibited higher levels of CHOL than those at 36 wk. Chicks from 64-wk-old breeders displayed an increase in LDLC when compared with the other two ages. These data suggest that serum concentrations of lipids and GLU, and RYSW in 18 d embryos and newly hatched chicks are influenced by hen age and not by added dietary fat.

Age Factors↗

PubMed1999

Dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans.

Understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. Rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. Analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance contribute independently to increased mammary gland tumorigenesis. These findings were seen in female rats fed diets high in fat (35-40% of calories) compared to rats fed control diets, with approximately 10% of calories as fat (Fay and Freedman, 1997, Breast Cancer Res. Treat. 46, 215-223). The methods used permit comparison of experimental and epidemiological data, and they may be useful in extrapolating between species and developing public health recommendations. In addition to the contributions of lifetime-diet composition, intake, energy balance, and physical activity to cancer risk, there are questions about the timing and duration of alterations in these factors and about the "dose-response" characteristics of cancer risk to the factors. Endocrine mechanisms may be significant in mammary gland tumor risk, but experimental and epidemiological data indicate that cancers at other sites, such as colon and liver, also are influenced by the factors listed. Other diet and lifestyle factors that influence energy, or specifically fat, metabolism may also affect risk for cancers that are promoted by increased intake of fat and calories. Studies of separate and interactive effects of dietary fat, black tea, weight gain, and mammary gland tumorigenesis (Rogers, et al, 1998, Carcinogenesis 19, 1269-1273) have been analyzed. Using adjustment of carcinogenesis endpoints for body weight, tumor burden, and latency, they were found to be related to weight gain within treatment groups in 2 of 3 experiments.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1987

Dietary fat and colon cancer: animal models.

During the past 15 years, human and animal model studies performed in our laboratory indicate that dietary fat plays an important role in the etiology of colon cancer. The effect of dietary fat during the stages of initiation and postinitiation of colon carcinogenesis depends on not only the amount of fat but also the type of fat and its fatty acid composition. Studies conducted in animal models have shown that high intake of dietary corn oil, beef fat, safflower oil, and lard increases colon carcinogenesis, whereas diets high in olive oil, coconut oil, and fish oil are without enhancing effect. The mechanisms by which various types of fat increase colon carcinogenesis are not fully understood; however, in most instances, the high-fat diet seems to enhance colon carcinogenesis through its elevation of agents that act as promoters of tumor development.

Animals↗

PubMed1994

Changes in cytochromes P-450, 2E1, 2B1, and 4A, and phospholipases A and C in the intragastric feeding rat model for alcoholic liver disease: relationship to dietary fats and pathologic liver injury.

The influence of dietary fat and alcohol on hepatic microsomal levels of cytochromes P-450 2E1, 2B, and 4A; phospholipases A and C; and UDP-glucuronosyltransferase was studied in the intragastric feeding rat model for alcoholic liver injury. Eight groups of animals were evaluated. Control and ethanol fed rats received either saturated fat or corn oil and were killed after 2 weeks and 1 month of feeding. All animals were pair-fed by continuous infusion of liquid diet through permanently implanted gastric cannulas. Alcoholic liver injury developed only in the corn oil-ethanol-fed groups and was manifest by 1 month. Livers were subjected to the following analyses: pathologic evaluation of liver injury; levels of cytochromes P-450 2E1, 2B, and 4A protein and mRNA; aniline hydroxylase activity; and phospholipase A and C and UDP-glucuronosyltransferase activities. Ethanol-induced increases in cytochromes P-450 2E1 and 2B protein determined by Western blotting were greatest in the corn oil-ethanol-fed group, which developed pathologic changes in the liver. Cytochromes P-450 2E1 and 2B1 mRNA levels were unaffected, suggesting that posttranscriptional mechanisms are responsible for the increase in the corresponding P-450 proteins. In contrast, cytochrome P-450 4A levels were higher in the saturated fat-ethanol groups compared with the corn oil-ethanol groups. Phospholipase A and phospholipase C levels were higher in the corn oil-ethanol groups compared with pair-fed dextrose controls and the saturated fat-ethanol groups. UDP-glucuronosyltransferase levels declined with time in the ethanol-fed groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2005

Dietary fats and membrane function: implications for metabolism and disease.

Lipids play varied and critical roles in metabolism, with function dramatically modulated by the individual fatty acid moities in complex lipid entities. In particular, the fatty acid composition of membrane lipids greatly influences membrane function. Here we consider the role of dietary fatty acid profile on membrane composition and, in turn, its impact on prevalent disease clusters of the metabolic syndrome and mental illness. Applying the classical physiological conformer-regulator paradigm to quantify the influence of dietary fats on membrane lipid composition (i.e. where the membrane variable is plotted against the same variable in the environment--in this case dietary fats), membrane lipid composition appears as a predominantly regulated parameter. Membranes remain relatively constant in their saturated (SFA) and monounsaturated (MUFA) fatty acid levels over a wide range of dietary variation for these fatty acids. Membrane composition was found to be more responsive to n-6 and n-3 polyunsaturated fatty acid (PUFA) levels in the diet and most sensitive to n-3 PUFA and to the n-3/n-6 ratio. These differential responses are probably due to the fact that both n-6 and n-3 PUFA classes cannot be synthesised de novo by higher animals. Diet-induced modifications in membrane lipid composition are associated with changes in the rates of membrane-linked cellular processes that are major contributors to energy metabolism. For example, in the intrinsic activity of fundamental processes such as the Na+/K+ pump and proton pump-leak cycle. Equally, dietary lipid profile impacts substantially on diseases of the metabolic syndrome with evidence accruing for changes in metabolic rate and neuropeptide regulation (thus influencing both sides of the energy balance equation), in second messenger generation and in gene expression influencing a range of glucose and lipid handling pathways. Finally, there is a growing literature relating changes in dietary fatty acid profile to many aspects of mental health. The understanding of dietary lipid profile and its influence on membrane function in relation to metabolic dysregulation has exciting potential for the prevention and treatment of a range of prevalent disease states.

Animals↗

PubMed1983

Response of bile flow, biliary lipids and bile acid pool in the pig to quantitative variations in dietary fat.

Bile flow, biliary lipids and bile acid pool have been studied in growing pigs adapted to a semipurified diet of 2, 10 or 20% lard. After a 5-day period of apparent digestibility measurement, bile secretion was studied in previously fistulated pigs. The apparent digestibility of lard was maintained at a very high level, whatever quantity of lard was ingested. Daily bile acid output was 49% higher with the 10% lard diet than with the 2% lard diet, whereas no further increase was observed with the 20% lard diet. There was a direct relationship between bile acid output and pool size. Biliary phospholipid output increased by 29.0% between 2 and 10% dietary lard and by 69.5% between 10 and 20% lard. The corresponding rise in biliary cholesterol output was +33% between 2 and 10 or 10 and 20% lard in the diet. A study of biliary kinetics showed that this adaptation of biliary lipid to dietary fat was observed whatever time of the light/dark cycle was considered. These results, together with a recent demonstration of the implication of endogenous phospholipids in fat digestion, suggested that, in the course of biliary lipid adaptation to dietary fat content, biliary phospholipid could act in synergy with bile salt, resulting in the maintenance of excellent dietary fat digestion.

Animals↗

PubMed1992

The combined effects of dietary fat, protein, and energy intake on azoxymethane-induced intestinal and renal carcinogenesis.

Two 3 x 3 factorial experiments were conducted to examine the effects of dietary protein (8, 16, and 32% of energy from casein) and dietary fat (12, 24, and 48% of energy from corn oil) on the initiation and promotion of azoxymethane-induced carcinogenesis in rats. For the initiation study, 33 weanling male Sprague-Dawley rats were randomized to each of nine diets fed ad libitum. Azoxymethane was administered s.c. between the fourth to sixth weeks of feeding, providing a total dose of 6 mg/100 g body weight. All rats were subsequently fed a common diet containing 16% energy from protein and 24% energy from fat for an additional 30 to 38 weeks. For the promotion study, all rats were fed a common diet containing 16% of energy from protein and 12% of energy from fat until the completion of azoxymethane administration, when 33 rats were randomized to each of nine diets varying in fat and protein content and fed these diets until sacrifice. Low-protein diets during the initiation phase were associated with increased risk of renal adenocarcinomas (P less than 0.001) and mesenchymal (P = 0.005) malignancies. No other statistically significant relationships were found between the levels of dietary fat or protein and the prevalence of malignant lesions of the small intestine, colon, or kidney in either the initiation or promotion study (although polypoid adenocarcinoma of the colon increased suggestively from 13 to 19 to 26% of rats with increasing dietary protein during initiation). Results of a multiple logistic regression analysis, combining both studies, showed that ad libitum energy intake was significantly associated with intestinal carcinogenesis. The odds of finding an intestinal adenocarcinoma increased by 6.2 +/- 2.6% (SE) for each additional kilocalorie of mean daily ad libitum intake (P = 0.014). The quintile of rats which consumed the least averaged 60 kcal/day, while the most voracious quintile averaged 74 kcal/day. This 14 kcal/day difference in mean ad libitum intake corresponded to more than a doubling (146% increase) of the odds of developing an intestinal adenocarcinoma. These studies suggest that ad libitum energy intake is a critical factor modulating experimental colon carcinogenesis.

Adenocarcinoma↗

PubMed2000

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.

Adult↗

PubMed2006

Modulating effects of dietary fats on methylmercury toxicity and distribution in rats.

Fish consumption is the most important source of human exposure to methylmercury (MeHg). Since fish is also a rich source of n-3 polyunsaturated fatty acids, this study was conducted to examine the effects of dietary fats on MeHg-induced acute toxicity in rats. Weanling male Sprague Dawley rats were administered semi-purified casein-based isocaloric diet containing soy oil, seal oil, docosahexaenoic acid (DHA), fish oil, or lard for 28 days. Rats were then gavaged with 0, 1, or 3 mg MeHg/kg body weight (BW) per day and fed the same diet for 14 consecutive days. On 43rd day of the experiment, rats were sacrificed and blood samples were collected and analyzed for hematology. Liver and spleen were removed, fixed, and examined for pathological changes. Blood, feces, liver, and brain were analyzed for total mercury and/or MeHg contents. Serum samples were analyzed for clinical markers of hepatic injury and immunoglobulin. Total mercury contents in all tissues measured increased with dose. Mercury excretion in feces increased with dose and duration of MeHg treatment. Both diets and MeHg showed significant effects and interacted significantly on many of the toxicological endpoints measured. Many of the effects of MeHg were diet-dependent. For example, in the rats fed the lard diet, 3mg MeHg/kg BW significantly increased relative liver and spleen weight as compared with vehicle control; whereas in rats fed the fish oil, soy oil, seal oil, or DHA, this effect of MeHg was less obvious or absent, suggesting a protective effect of these diets. MeHg at 3mg/kg BW significantly decreased serum albumin level in all except DHA dietary groups, implying a protection by the DHA diet on this parameter. Only in the lard dietary group, did 3mg MeHg/kg BW significantly increase serum bilirubin level, indicating an enhancing effect of this diet on MeHg toxicity. MeHg suppressed the adaptive immune system and stimulated the innate immune system in rats in a diet-dependent fashion. The seal oil diet provided more resistance, while the fish oil diet rendered greater sensitivity to these effects of MeHg on the immune system. These results imply significant modulating effects of dietary fats on MeHg toxicity which may translate into more severe or protective clinical outcomes. Therefore, dietary fats are important factors to be considered in the risk assessment of MeHg exposure.

Animals↗

PubMed1994

The Eating Pattern Assessment Tool: a simple instrument for assessing dietary fat and cholesterol intake.

OBJECTIVE: This study describes the development of the self-administered Eating Pattern Assessment Tool (EPAT), which is designed to assess dietary fat and cholesterol intake and aid patients and health professionals in achieving control of blood cholesterol levels. DESIGN: Test-retest reliability of the instrument over five visits and concurrent validity testing compared with 4-day food records. SETTING AND SAMPLE: The instrument was tested at multiple sites of a large manufacturing corporation using 436 adult volunteers with approximately equal proportions of men and women from three socioeconomic levels. MAIN OUTCOME MEASURE: Development of the EPAT centered on creating an instrument that was simple and easy to use in a primary-care setting, that would provide a reliable assessment of intake of dietary fat and cholesterol among adults, and that would measure frequency of consumption of foods from high-fat and low-fat categories. ANALYSES: Test-retest reliability for repeated use was estimated by between-visit Pearson product-moment correlations of EPAT section scores. Concurrent validity was assessed by using product-moment correlation between EPAT section scores and mean daily B-scores obtained from 4-day food records. RESULTS: Test-retest reliability estimates were 0.91 between all adjacent pairs of visits and 0.83 between visits 1 and 5 (4 months). Validity was 0.56. APPLICATIONS/CONCLUSIONS: The EPAT is a simple, quick, self-administered tool using an easy scoring method for accurately assessing fat and cholesterol intake. It is a reliable and valid substitute for more time-consuming food records. EPAT also provides an efficient way to monitor eating patterns of patients over time and is arranged to provide an educational message that reinforces the consumption of recommended types and numbers of servings of low-fat foods.

Adult↗

PubMed1991

Dietary cholesterol influences on various lipid indices and eicosanoid production in rats fed dietary fat desirable for the protection of ischemic heart disease.

Young male Sprague-Dawley rats were fed diets containing 10% fat with P/S and n-6/n-3 ratios of 1.2 and 5.0, respectively, and differing levels of dietary cholesterol (0.05 to 1.0% by weight) for 3 weeks, following which the tissue lipid concentration, fatty acid composition, desaturation of linoleic acid, and eicosanoid production were examined. The composition of dietary fat was that recommended for the prevention of atherosclerosis. Dietary cholesterol did not largely influence the concentration of serum cholesterol, but it markedly increased liver cholesterol in a dose-dependent manner. The delta 6-desaturase activity in liver microsomes, linoleate desaturation index in liver phosphatidylcholine, and the production of prostaglandin by the aorta and thromboxane A2 by platelets all decreased to a similar extent in relation to dietary cholesterol above 0.2%. Thus, dietary cholesterol influenced various lipid parameters characteristically even when dietary fat with a fatty acid composition desirable for the prevention of atherosclerosis was consumed simultaneously. The dietary cholesterol level of 0.2% was the point of maximum influence in rats upon the indices examined.

Animals↗

PubMed1996

Dietary fat effects on brush border membrane composition and enzyme activities in rat intestine.

The effect of dietary fats on the chemical composition and enzyme activities has been studied in intestinal brush border membranes (BBM) or rats. Animals were given commercial rat pellet diet (RP) or semisynthetic diet rich in either saturated [coconut oil (CCO))] or polyunsaturated [n-6, corn oil (CO) or n-3, fish oil (FO)] fat at the 10% level for 5 weeks. The membrane cholesterol/phospholipid ratio was augmented in CO- or RP-fed rats. There was an increase in level of saturated fatty acids in BBM from CCO- or FO-fed animals. n-3 polyunsaturated fatty acid content was raised in FO-fed rats, while the proportion of linoleic acid and arachidonic acid was enhanced in animals given a CO diet. Membrane fluidity was in the order of CCO < RP = CO < FO. The membrane hexose content was high (p < 0.05) in the CCO group. Hexosamines were elevated (p < 0.05) in CCO- or FO-fed rat brush borders. Membrane fucose was unaltered, while sialic acid content was elevated in CO- (p < 0.05) and FO- (p < 0.01) fed vs. CCO-fed rats. Lectin binding to brush borders corroborated these findings. The activities of alkaline phosphatase, sucrase and lactase were augmented (p < 0.001) in CCO-fed animals. Leucine-aminopeptidase and sucrase activities were depressed by FO feeding. The activities of PNP-beta-glycosidases were the highest in FO-fed rats. These results indicate that dietary fat quality markedly affects microvillus membrane lipid composition, glycosylation and enzyme functions in rat intestine.

Alkaline Phosphatase↗

PubMed1996

Dietary fat affects heat production and other variables of equine performance, under hot and humid conditions.

Does dietary fat supplementation during conditioning improve athletic performance, especially in the heat? Fat adaptation has been used to increase energy density, decrease bowel bulk and faecal output and reduce health risks associated with hydrolysable carbohydrate overload. It may also reduce spontaneous activity and reactivity (excitability), increase fatty acid oxidation, reduce CO2 production and associated acidosis, enhance metabolic regulation of glycolysis, improve both aerobic and anaerobic performance and substantially reduce heat production. A thermochemical analysis of ATP generation showed the least heat release during the direct oxidation of long chain fatty acids, which have a 3% advantage over glucose and 20 to 30% over short chain fatty acids and amino acids. Indirect oxidation via storage as triglyceride increased heat loss during ATP generation by 3% for stearic acid, 65% for glucose and 174% for acetic acid. Meal feeding and nutrient storage, therefore, accentuates the advantage of dietary fat. A calorimetric model was based on initial estimates of net energy for competitive work (10.76 MJ for the Endurance Test of an Olympic level 3-day-event), other work (14.4 MJ/day) and maintenance (36 MJ), then applied estimates of efficiencies to derive associated heat productions for the utilisation of 3 diets, Diet A: hay (100), Diet B: hay and oats (50:50) and Diet C: hay, oats and vegetable oil (45:45:10), the difference between the last 2 diets representing fat adaptation. During a 90.5 min speed and stamina test, heat production was estimated as 37, 35.4 and 34.6 MJ for the 3 diets, respectively, an advantage 0.8 MJ less heat load for the fat adapted horse, which would reduce water needed for evaporation by 0.33 kg and reduce body temperature increase by about 0.07 degree C. Total estimated daily heat production was 105, 93 and 88 MJ for the 3 diets, respectively, suggesting a 5 MJ advantage for the fat adapted horse (Diet C vs. Diet B). Estimated intake energy was 348, 269 and 239 MJ for the 3 diets, respectively, and corresponding daily intakes as fed were 22.2, 16.6 and 12.9 kg, an advantage of 3.7 kg for the fat adapted horse. Water requirement was estimated to decrease by about 6 kg/day in the fat adapted horse: 4 kg less faecal water output and 2 kg less water for evaporation. This model indicated that the fat supplemented diet reduced daily heat load by 5%, feed intake by 22%, faecal output (and bowel ballast) by 31% and water requirement by 12%. The advantage of fat supplementation over hay and oats was in general about half that gained by hay and oats over hay alone.

Adenosine Triphosphate↗

PubMed1994

Influence of mutation in human apolipoprotein A-1 gene promoter on plasma LDL cholesterol response to dietary fat.

The plasma lipid response to changes in dietary fat and cholesterol can vary between individuals. At present, responders cannot be identified in advance. An adenine to guanine (A-->G) mutation in the promoter of the apolipoprotein A1 gene (apoA-1) has been suggested as affecting plasma high-density lipoprotein cholesterol. In 50 young men we examined the effect of the same mutation on the responses of both high and low density lipoprotein cholesterol to low-fat diet. The frequency for the A allele was 0.14. Subjects were fed a low-fat diet for 25 days, followed by a diet rich in monounsaturated fatty acid (MUFA, 22% out of 40% fat) for 28 days and lipoproteins were measured at the end of each diet. There were no differences in initial total cholesterol between subjects with the G/G mutation (170 mg/dL: 100 mg/dL = 2.59 mmol/L) and the G/A mutation (169 mg/dL) genotypes. After consumption of the high monounsaturated fat diet, significant increases were noted in plasma LDL cholesterol (10 mg/dL, p = 0.035) in the G/A subjects but not in the G/G subjects (1 mg/dL, p = 0.996). These differences showed that a significant diet-gene interaction (p = 0.015) existed. No differences were observed on HDL cholesterol between groups. Plasma low-density lipoprotein cholesterol responsiveness to diet may be explained by variation at the apoA-I gene locus.

Adult↗

PubMed1992

Role of dietary fat in obesity. Fat is fattening.

Total caloric intake has not increased significantly over the last century as obesity increased, but there has been an increase in consumption of dietary fat. Its role in obesity is reviewed. Fat is the most concentrated form of calories in the diet; being compact, it contributes to overeating. High fat foods can be eaten faster with less chewing. Dietary fat is the most efficiently stored foodstuff, thus contributing to obesity. A low fat diet is an important adjunct to advising decreasing caloric intake for a weight reduction plan. Physicians should advise patients to decrease fat, not just "count calories."

Dietary Fats↗