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PubMed1989

Effects of dietary fats on fatty acid composition and delta 5 desaturase in normal and diabetic rats.

We have studied the effect of various diets on the phospholipid fatty acid composition and in vitro delta 5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin-induced diabetic rat. The diets studied were the standard rat chow diet and a basal fat-free diet supplemented either with 20 percent saturated fat, 20 percent unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased delta 5 desaturase activities and decreased 18:2n-6 intake. On the contrary, the unsaturated fat diet decreased dihomo-gamma-linolenate and increased arachidonate levels, without increased delta 5 desaturase activity. Streptozotocin-induced diabetes resulted in decreased arachidonate and delta 5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased delta 5 desaturase activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n-3 fatty acids in both normal and diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids. Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n-6 fatty acids, reduced delta 5 desaturase activity, and enhanced 22:6n-3 incorporation into diabetic microsomes.

Animals↗

PubMed2006

Vitamin K intake and calcifications in breast arteries.

OBJECTIVES: Vitamin K is an important co-factor in the production of proteins that inhibit vascular calcification. A low dietary Vitamin K intake has been associated with aortic and coronary calcifications and an elevated cardiovascular risk. Calcifications in the arteries of the breasts have also been associated with cardiovascular risk, but whether there is a relation with a low Vitamin K intake has not yet been studied. METHODS: We conducted a cross-sectional study among 1689 women, aged 49-70 years. Dietary Vitamins K1 and K2 intake was calculated from a validated food frequency questionnaire. Breast arterial calcifications (BAC) were assessed on standard screening mammograms by two independent radiologists. With a general linear model mean Vitamins K1, K2 and Vitamin K2 subtypes were calculated for women with BAC and without, adjusted for age, smoking, diabetes, intake of saturated fat, mono-unsaturated fat, poly-unsaturated fat and protein- and calcium-intake. RESULTS: BAC was less common in the highest (9%) quartile of Vitamin K2 intake, compared to the lowest (13%) (OR 0.7, 95% CI 0.5-1.1) and not different across quartiles of Vitamin K1 intake. Mean Vitamin K2 levels and mean levels of Vitamin K2 subtypes MK-5 through MK-10 were lower in the participants with BAC (p=0.01) compared to participants without BAC. However, after adjustment for aging, smoking, diabetes and dietary factors the association of mean Vitamin K2 intake with BAC was no longer significant. CONCLUSION: Calcifications in breast arteries are not associated with a lower dietary intake of Vitamin K.

Aged↗

PubMed1997

Macronutrients, energy intake, and breast cancer risk: implications from different models.

We used data from a case-control study, conducted in Italy on 2,569 incident cases of breast cancer and 2,588 controls, to fit various energy adjustment models in the estimate of the effect of selected nutrients and alcohol on breast cancer risk. When we fit the standard multivariate and residual models, including total energy intake and the different macronutrients one at a time, the odds ratios (OR) related to 100 kcal per day were 0.90 for protein, 0.96 for saturated fat, 0.88 for unsaturated fat, 0.95 for sugar, 1.07 for starch, and 1.06 for alcohol. When we included all of the different sources of calorie intake in a single model with energy sources partitioned, the OR of adding 100 kcal per day was 0.91 for protein, 1.22 for saturated fat, 0.89 for unsaturated fat, 0.98 for sugar, 1.08 for starch, and 1.07 for alcohol. The estimates from the residual models that included various macronutrients separately were similar to those of the extended energy partition model.

Adult↗

PubMed1989

Seven Countries Study. First 20-year mortality data in 12 cohorts of six countries.

Out of the original 16 cohorts in the Seven Countries Study on Cardiovascular Diseases, 12 population samples in six countries have reached the 20 year follow-up deadline. Data on mortality became fully available for a total of 8287 men aged 40-59 at entry examination (two cohorts in Finland, one in the Netherlands, three in Italy, two in Yugoslavia, two in Greece, and two in Japan). Death rates from CHD as well as from all causes follow the traditional falling north to south trend (18 fold between the extremes for CHD; 2.7 fold for total mortality). The differences in all causes mortality are, however, largely accounted for by the variation in CHD mortality. The mean entry levels of serum cholesterol and representative levels of the consumption of saturated fats, mono-unsaturated fats, poly-unsaturated fats and carbohydrates explain a large proportion of inter-cohort difference in CHD mortality (81% for saturated fats). By applying the proportional hazards model to the pools of national cohorts, with CHD deaths as end-point and five risk factors as covariates, only age and mean blood pressure are universally significant predictors of fatal events. Cholesterol, smoking habits, body mass index and physical activity play some part but not in all the pools. Age and mean blood pressure are also the only universal risk factors for all causes of death.

Adult↗

PubMed1997

Dietary fat intake and risk of prostate cancer: a prospective study of 25,708 Norwegian men.

The relationship between incidence of prostate cancer and intake of dietary fat and foods rich in fat was studied in 25,708 men aged 16-56 years attending a Norwegian health screening in 1977-1983. Linkage to the Cancer Registry of Norway and the Central Bureau of Statistics of Norway ensured a complete follow-up until December 31, 1992. Diet was recorded on a semi-quantitative food-frequency questionnaire at the time of screening, and 72 cases of prostate cancer were identified during follow-up. At the end of follow-up, mean age of the total study sample was 56 years (range 19-68), while mean age at diagnosis of prostate cancer was 60 years (range 47-67). No association was found between energy-adjusted intake of total fat, saturated fat, mono-unsaturated fat or poly-unsaturated fat and the incidence of prostate cancer. Significant positive associations were found for body mass index (BMI) and consumption of hamburgers/meatballs, while no association was found with consumption of frankfurters/sausages and a significant negative association with the weekly number of main meals with meat. A significantly increased risk of prostate cancer was associated with skim milk as compared to whole milk. Milk preference (skim vs. whole) was associated significantly positively with BMI. Our study of a relatively young cohort does not confirm previous case-control and cohort studies suggesting that dietary fat, especially from animal sources, is associated positively with risk of prostate cancer.

Adenocarcinoma↗

PubMed1994

Dietary fat affects plasma prolactin in female F344 rats under conditions of ether stress.

The influence of amount and type of dietary fat on circulating concentrations of prolactin and estradiol-17 beta in female F344 rats from which blood was sampled by decapitation under ether anesthesia was compared with that in rats from which blood was collected without anesthesia. The animals were fed isonutrient (adjusted for differences in energy density) semipurified diets containing 5% or 20% (by weight) sunflower seed oil or lard. Blood was sampled by decapitation with or without standardized ether anesthesia during the afternoon of proestrus-estrus or the morning of metestrus-diestrus, as determined by examination of vaginal smears. Plasma hormone concentrations were measured by radioimmunoassay. Prolactin levels were lower during proestrus-estrus in rats fed a low-fat diet than in animals fed a high-fat diet, statistically independent of the type of dietary fat, but only when blood was sampled by decapitation under ether anesthesia [p = 0.0384, 2-way analysis of variance (ANOVA)]. No such difference was found in rats decapitated without anesthesia. This effect of amount of dietary fat on prolactin in proestrus-estrus animals anesthetized with ether was predominantly present in animals fed polyunsaturated fat (p < 0.05, 1-way ANOVA and Tukey's test) and was statistically not significant in rats fed saturated fat diets. During metestrus-diestrus, prolactin levels were significantly lower in animals fed a high-saturated fat diet than in those fed low-saturated fat, low-unsaturated fat, or high-unsaturated fat diets, independent of the blood sampling conditions (p < 0.05, 2-way ANOVA and Tukey's test). No consistent effects on estradiol-17 beta levels were found in type or amount of dietary fat or in presence or absence of ether anesthesia before decapitation. Growth, apparent digestibility of fat, and caloric intake were similar in all four dietary groups, but food consumption was higher and food conversion efficiency was lower in animals fed low-fat diets than in those fed high-fat diets. This study confirms the hypothesis that effects of dietary fat, particularly polyunsaturated fat, on circulating prolactin occur only during (ether) stress. Because stress is a frequent and normal phenomenon, this observation implies that the mammary glands of animals with a high dietary intake of polyunsaturated fat are frequently exposed to higher circulating prolactin concentrations than rats fed a low-fat diet, which may be a major mechanism by which dietary fat enhances rat mammary carcinogenesis.

Anesthesia, General↗

PubMed1987

Effects of dietary saturated and polyunsaturated fat on lipoprotein lipase and hepatic triglyceride lipase activity.

The effects of saturated and polyunsaturated dietary fat on the lipolytic activity of post-heparin plasma, lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were studied in the rat. The lipolytic activity was studied from 0 to 60 min using labelled chylomicrons as the substrate. Triacylglycerol hydrolysis rate was higher for the plasma of rats fed high fat diets (14% fat by weight). Chylomicrons of rats fed saturated or unsaturated fats were hydrolyzed at the same rate within the first 15 min but afterwards hydrolysis of chylomicrons of rats fed saturated fat was slower. The activities of LPL and HTGL were increased by high fat diets. Unsaturated fat increased more LPL activity than saturated fat conversely, HTGL activity was enhanced more by saturated fat than by unsaturated fat.

Animals↗

PubMed2004

Impact of nutrition counselling on nutrition knowledge and nutrient intake of 7- to 9-y-old children in an atherosclerosis prevention project.

OBJECTIVE: To assess the impact of nutrition counselling given to 7.5- to 9-y-old children and their parents on children's nutrition knowledge and nutrient intakes. DESIGN AND SUBJECTS: The study children are participants in a prospective, randomised STRIP study (Special Turku Coronary Risk Factor Intervention Project for Children), whose aim was to decrease the intakes of saturated fat and cholesterol while increasing the intake of unsaturated fat in the intervention children from the age of 7 months onwards. Nutrition counselling was given only to the parents until the child's age of 7 y. Nutrition knowledge and nutrient intakes (total energy, total fat, saturated fat, unsaturated fat and sodium) were studied in a time-restricted cohort of 47, 7-y-old intervention and 51 control children. Thereafter, nutrition counselling was given both to the children and parents. Children's nutrition knowledge and nutrient intakes were measured again at the age of 9 y. RESULTS: Biannual nutrition counselling given to the intervention children and the parents maintained the differences in saturated fatty acid intake attained during the intervention given to the parents alone (11.5 vs 13.3 E% (percent of energy intake), at the age of 7 y, P<0.01; 11.1 vs 13.4 E% at the age of 9 y, respectively; P<0.01). The intervention children used more polyunsaturated fatty acids at the age of 9 y than the control children (5.7 vs 5.1 E%, P=0.05). At 7 y, the intervention and control children had similar nutrition knowledge scores (total knowledge score 12.9 vs 12.0, respectively, P=0.13). After 1.5 y of nutrition intervention, at 9 y, the intervention children's nutrition knowledge was higher than that of the controls (total nutrition score 16.5 vs 13.2, respectively, P<0.001) and the ability to explain the reasons for their picture choices in the nutrition knowledge test had increased. CONCLUSION: This study showed that only a relatively short period of counselling with low input is needed to increase in children's nutrition knowledge and ability to explain nutrition-related subjects if advice has first been given to the parents and if the parents have received reinforcement and concrete help with parent-child communication after their children have been involved in the counselling. The differences attained in nutrient intake could also be maintained.

Arteriosclerosis↗

PubMed1989

Effect of dietary lipids on hepatic and plasma beta-carotene and vitamin A levels in rats fed beta-carotene.

Diets low in carotenoids have been associated with greater risks of developing certain cancers. Diets high in fats, especially unsaturated fats, have also been associated with increased risks of developing cancer. This study was undertaken to evaluate the effect of fat type on the beta-carotene status in a rat model. Rats were fed diets containing 2 g/kg beta-carotene or placebo and either 10% lard or corn oil for 13-16 weeks. Plasma vitamin A was unaffected by the dietary regimes. Liver vitamin A levels were significantly increased in the beta-carotene groups and were greater in the lard-fed animals. No detectable level of plasma beta-carotene was found in the rats fed placebo diets. In animals given dietary beta-carotene, plasma beta-carotene levels were significantly reduced in the group fed corn oil compared to the group fed lard. Liver beta-carotene levels were higher in the groups fed corn oil. The results suggest that the type of dietary fat can significantly affect the circulating and tissue levels of beta-carotene.

Animals↗

PubMed1995

LDL receptor activity is down-regulated similarly by a cholesterol-containing diet high in palmitic acid or high in lauric and myristic acids in cynomolgus monkeys.

To determine the mechanisms whereby diets differing widely in fatty acid composition affect plasma LDL cholesterol and apolipoprotein B concentrations, LDL kinetics and receptor- and nonreceptor-mediated LDL catabolism were investigated in 27 cynomolgus monkeys fed diets containing 0.05 mg cholesterol/kJ and 40% fat energy as corn oil alone (unsaturated fat diet rich in oleic and linoleic acids), nonhydrogenated coconut oil alone (saturated fat diet, rich in lauric and myristic acids) or an oil blend (rich in palmitic acid). Consumption of the oil blend and saturated fat diets significantly elevated total cholesterol, LDL cholesterol and apolipoprotein B concentrations relative to the unsaturated fat diet and the saturated fat diet significantly increased plasma total cholesterol and LDL cholesterol compared with the oil blend diet. However, despite the greater increases in plasma total cholesterol, LDL cholesterol and apolipoprotein B in the saturated fat vs. the oil blend dietary group, the receptor-mediated LDL fractional catabolic rate was comparable in the oil blend and saturated fat diet groups. In addition, consumption of the oil blend or saturated fat diet increased the production rate of LDL apolipoprotein B and nonreceptor-mediated LDL apolipoprotein B transport (disposal) relative to the unsaturated fat diet. Our data, therefore, suggest that consumption of the oil blend or saturated fat diet elevated plasma total cholesterol and LDL cholesterol relative to the unsaturated fat diet, and the oil blend diet abundant in palmitic acid seems to have down-regulated the LDL receptor as much as a more saturated fat diet abundant in lauric and myristic acids.

Animals↗

PubMed1986

Dietary fat influences the expression of autoimmune disease in MRL/lpr/lpr mice.

Near-isocaloric diets with qualitative and quantitative differences in fat content have a profound influence on the manifestation and progression of the autoimmune syndrome that occurs in female MRL/lpr mice. In these animals, a high (9%) lipid intake resulted in a significantly higher mortality rate: 60% (saturated fat) and 75% (unsaturated fat) compared to 35% at 1 year for a group fed a diet low in fat. Furthermore, beginning at 7 months of age mice from both of the high fat diet groups exhibited a significantly higher incidence of proteinuria than mice in the low fat group. Immunologically, the group fed the high unsaturated fat diet had the highest incidence of anti-dsDNA autoantibodies, and the high saturated fat group had the poorest macrophage phagocytic function. The low fat diet preserved near 'normal' immune function in general, particularly IL-2 production. No significant differences were noted in either the production of rheumatoid factor or natural killer cell activity, irrespective of age or diet.

Animals↗

PubMed1994

Vagotomy and mercaptoacetate influence the effect of dietary fat on macronutrient selection by rats.

We have previously shown that rats fed saturated fat prefer a high protein, low carbohydrate diet, whereas animals fed unsaturated fat prefer a low protein, high carbohydrate diet. The purpose of the present study was to determine whether this "saturated fat effect" requires 1) the oxidation of the dietary fat and 2) an intact hepatic vagus nerve. Male Sprague-Dawley rats were vagotomized (hepatic branch) or sham-operated and injected with either mercaptoacetate (fatty acid oxidation inhibitor) or saline. Next, half of each group was given saturated fat (beef tallow) or unsaturated fat (corn oil) by gastric tube. All animals were given a choice between two mixed diets that differed in protein and carbohydrate. Sham-operated rats fed saturated fat ate more of the protein diet than did rats fed unsaturated fat. Vagotomy attenuated the intake of the protein diet in animals fed saturated fat. Mercaptoacetate or vagotomy had no effect on diet selection in rats fed unsaturated fat. These data indicate that the effect of saturated fat on diet selection requires an intact hepatic vagus and may be modulated by fatty acid oxidation. Furthermore, the mechanism for altering diet selection can be induced after a single meal.

3-Hydroxybutyric Acid↗

PubMed1990

Effects of feeds on flavor of red meat: a review.

The effects of diet ingredients on red meat flavor are dependent on the type of diet, and, to a large extent, on the species: pork, mutton or lamb and beef. Sensory analysis of meat flavor has been used in most of the studies on the effects of feeds on meat flavor. In general, high-energy grain diets produced a more acceptable or a more intense flavor in red meats than low-energy forage or grass diets. Feeding pigs unsaturated fats increases the unsaturation in pork fat but results in only minor changes in pork flavor. Sheep must be fed protected, unsaturated fats in order to increase the unsaturation in their fat to be similar to pork fat. This increased unsaturation results in a greater flavor change in lamb or beef than in pork. Several dietary ingredients such as fish products, raw soybeans, canola oil and meal, and pasture grasses cause undesirable flavors in red meat. Analyses of lamb and beef produced on different diets have shown that type of feed affects the concentration of many flavor volatile compounds. However, only a few studies have quantified the volatiles of beef and lamb produced on different diets, and no reports of studies were found in which the volatiles of pork produced on different diets had been investigated. Hence, the importance of these changes in volatile concentration to meat flavor has not been determined.

Animal Feed↗

PubMed2003

Dietary fats and the risk of incident Alzheimer disease.

BACKGROUND: Few studies have investigated the effects of dietary fats on the development of Alzheimer disease. We examined the associations between intake of specific types of fat and incident Alzheimer disease in a biracial community study. METHODS: We performed clinical evaluations on a stratified random sample of 815 community residents aged 65 years and older who were unaffected by Alzheimer disease at baseline and who completed a food-frequency questionnaire a mean of 2.3 years before clinical evaluation. RESULTS: After a mean follow-up of 3.9 years, 131 persons developed Alzheimer disease. Intakes of saturated fat and trans-unsaturated fat were positively associated with risk of Alzheimer disease, whereas intakes of omega-6 polyunsaturated fat and monounsaturated fat were inversely associated. Persons in the upper fifth of saturated-fat intake had 2.2 times the risk of incident Alzheimer disease compared with persons in the lowest fifth in a multivariable model adjusted for age, sex, race, education, and apolipoprotein E epsilon4 allele status (95% confidence interval, 1.1-4.7). Risk also increased with consumption of trans-unsaturated fats, beginning with the second fifth of intake (relative risk, 2.4 compared with the lowest fifth; 95% confidence interval, 1.1-5.3). We observed linear inverse associations between Alzheimer disease and vegetable fat (P =.002), and, after further adjustment for other types of fat, marginally significant associations with intake of omega-6 polyunsaturated fat (P =.10 for trend) and monounsaturated fat (P =.10 for trend). Intakes of total fat, animal fat, and dietary cholesterol were not associated with Alzheimer disease. CONCLUSION: High intake of unsaturated, unhydrogenated fats may be protective against Alzheimer disease, whereas intake of saturated or trans-unsaturated (hydrogenated) fats may increase risk.

Aged↗

PubMed1992

Dietary and erythrocyte fatty acids in experimental colorectal carcinogenesis.

The influence of dietary fat on the erythrocyte stearic:oleic acid ratio was investigated in an experimental model of colorectal cancer. One hundred male Wistar rats were divided into four separate dietary groups: A (5% saturated fat), B (20% saturated fat), C (5% n-6 unsaturated fat) or D (20% n-6 unsaturated fat). Colorectal tumours were induced by intraperitoneal injection of azoxymethane (n = 60) and control animals received saline (n = 40). Animals were killed after 26 weeks and erythrocyte fatty acid profiles were determined by gas liquid chromatography. Although there were no differences in the incidence of adenoma formation in the four dietary groups, there was a significantly lower incidence of carcinomas in rats fed a 5% or 20% unsaturated fat diet when compared with either a 5% (P less than 0.05) or a 20% saturated fat diet (P less than 0.01). Multivariate analysis of fatty acid profiles demonstrated that both the type and quantity of dietary fat had a highly significant influence on the fatty acid profile of erythrocytes. The stearic:oleic acid ratio varied considerably between the four dietary groups but was only significantly lower in tumour bearing animals compared with controls in group B (20% saturated fat diet).

Animals↗

PubMed1991

Bile composition of adult baboons is influenced by breast versus formula feeding.

We tested the hypothesis that infant cholesterol intake and breast- versus formula-feeding influence the bile cholesterol saturation index and bile acid conjugate composition in adult baboons at 7-8 years of age. We also measured the influence of the postweaning intake of dietary cholesterol and fat (saturated and unsaturated) on the effects of the infant diets. The 80 baboons were derived from six sires and 80 dams and randomly assigned at birth to breast-feeding or to one of three formulas containing about 2, 30, or 60 mg cholesterol/dl. After weaning at 16 weeks of age the animals were assigned to one of four adult diets, which contained 0.01 or 1.0 mg/kcal of cholesterol containing 40% of calories from saturated or unsaturated fat. The bile cholesterol saturation index was significantly higher at 7-8 years of age in baboons breast-fed as infants compared with those fed formula (87.0% versus 72.8%, p less than 0.004). The cholesterol saturation index was not significantly different among the three formula groups. Among baboons who were breast-fed and subsequently fed saturated fat as adults, the glycine/taurine (G/T) ratios of the bile acid conjugates were about three times those of baboons fed unsaturated fat (1.53 versus 0.47); whereas among formula-fed animals the type of fat did not influence the G/T ratio (interaction, p = 0.022). Adult baboons fed the three formulas in infancy had an inverse relationship of the G/T ratio to the level of formula cholesterol (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

Protein modification by advanced Maillard adducts can be modulated by dietary polyunsaturated fatty acids.

Advanced Maillard adducts, such as N epsilon-(carboxymethyl)lysine and N epsilon-(carboxyethyl)lysine, can be formed efficiently in vitro from both peroxidation of polyunsaturated fatty acids and glycolysis intermediates. In an attempt to differentiate the in vivo influence of the two pathways in these modifications, Wistar rats were chronically fed with specially designed diets rich in saturated or unsaturated fats. The degree of fatty acid unsaturation of all analysed organs (liver, kidney, brain) was altered by these dietary stresses. Protein glycoxidative and lipoxidative modifications were measured by GC/MS. In accordance with fatty acid profiles, concentrations of N epsilon-(malondialdehyde)lysine in these tissues were significantly increased in animals fed the unsaturated fat diet. In contrast, N epsilon-(carboxymethyl)lysine and N epsilon-(carboxyethyl)lysine concentrations were strongly dependent on the tissue analysed; although the unsaturated fat diet increased their levels significantly in brain, levels were unchanged in kidney and decreased in liver. These later results could be interpreted on the basis that polyunsaturated fatty acids decrease the expression of several glycolytic enzymes in liver. Globally, these data suggest that tissue-specific metabolic characteristics play a key role in the degree of cellular protein modification by Maillard reactions, e.g. by modulation of the concentration of glycolysis intermediates or via specific defensive systems in these organs.

Animals↗

PubMed1987

Effects of fatty acids on gap junctional communication: possible role in tumor promotion by dietary fat.

Dietary lipids, in particular unsaturated fat, promote the development of many experimental tumors. However, no mechanisms to fully explain these effects have been elucidated. Recent reports, which we summarize here, suggest a role for gap junction-mediated intercellular communication in the process of tumor promotion. We also review tumor-promoting effects of dietary fat on experimental, particularly mammary, carcinogenesis. Our main focus is to review recent data examining the inhibitory effects of unsaturated fatty acids on metabolic cooperation in Chinese hamster V79 cells. These data suggest that inhibition of junctional communication may be involved mechanistically in the promotion of tumors by high levels of dietary unsaturated fat. Finally, potential mechanisms by which unsaturated fatty acids inhibit metabolic cooperation are examined.

Animals↗