| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Dietary fat saturation, but not the feeding state, modulates rates of cholesterol esterification in normolipidemic men Mazier, M. J. and P. J. Jones (1999), Metabolism 48(10): 1210-5. Abstract: To determine whether the rates of cholesterol esterification in normal individuals are affected by diets differing in fats, nine men were randomly assigned to three groups receiving a diet rich in monounsaturated (MONO), polyunsaturated (POLY), or saturated (SAT) fat for 2 weeks using a crossover design. Subjects drank a dose of deuterium oxide, and the fractional esterification rate (FER) was calculated during fed and unfed periods. Total esterified cholesterol was calculated as the product of the FER and pool size, the latter obtained from a decay curve following injection of 4-14C-cholesterol. The POLY diet produced the lowest serum cholesterol concentration and the SAT diet the highest (P <.001). For cholesterol ester (CE) deuterium enrichment, an interaction was noted between diet and time (P <.01). The FER was greater (P <.003) in subjects fed the POLY diet versus either of the other diets, although the amount of esterified cholesterol produced, expressed as either milligrams per day (P <.103) or milligrams per kilogram of body weight per day (P <.100), did not differ among groups. No effect of the feeding state was found for either the FER (P <.187) or total esterified cholesterol expressed as milligrams per day (P <.146) or milligrams per kilogram of body weight per day (P <.128). The results suggest that the diet fat type, but not the feeding state, may be responsible for serum esterified cholesterol concentrations. |
| Dietary fat source and cholesterol interactions alter plasma lipids and tissue susceptibility to oxidation in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats Yuan, Y. V. and D. D. Kitts (2002), Mol Cell Biochem 232(1-2): 33-47. Abstract: Due to the potential for dietary fat source to alter plasma lipids and tissue antioxidant status, we hypothesized that blends of saturated, n-6 and n-3 fats with cholesterol would affect LDL and tissue susceptibility to in vitro oxidation. The effects of dietary fat blends of butter (B), beef tallow (T), soybean oil (SBO) or menhaden oil (MO) and cholesterol on systolic blood pressure (SBP), plasma lipoproteins and tissue susceptibility to glutathione (GSH) depletion and lipid peroxidation (TBARS) were examined in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. SBP in SHRs was higher (p < 0.001) than in WKYs at 13-weeks of age but was not altered by dietary fat or cholesterol. LDL- and HDL-cholesterol were greater (p < 0.001) in WKY than SHR. LDL-cholesterol and (VLDL- + LDL-cholesterol)/HDL-cholesterol ratios were reduced in MO vs. B, T and SBO groups. HDL-cholesterol levels tended to be lower and greater in B and MO groups, respectively vs. T and SBO groups. Initial LDL fluorescence was greater (p < 0.001) in high- vs. low-cholesterol groups. The change in LDL fluorescence was reduced (p < 0.001) in high-cholesterol groups, and MO vs. B, T and SBO rats. MO fed rats had reduced (p < 0.001) RBC, heart and liver GSH depletion and reduced (p < 0.01) tissue TBARS and RBC MDA production. In summary, a moderate level of dietary MO did not increase tissue and LDL in vitro oxidizability in SHR and WKY rats. High dietary cholesterol exhibited a protective effect against in vitro oxidation of LDL and selected tissues. |
| Dietary fat type and cholesterol quantity interact to affect cholesterol metabolism in guinea pigs Lin, E. C., M. L. Fernandez, et al. (1992), J Nutr 122(10): 2019-29. Abstract: Interactions of dietary fat saturation with dietary cholesterol on cholesterol homeostasis in guinea pigs were studied by feeding 15% (wt/wt) fat diets containing lard, olive oil or corn oil, with 0.00, 0.08, 0.17 or 0.33% added cholesterol. Plasma total and LDL cholesterol concentrations significantly increased with increasing dietary cholesterol, with pronounced increments occurring at the pharmacologic (0.33%) level. An interaction between fat type and dietary cholesterol was seen for HDL cholesterol concentrations. Saturated fat and the pharmacologic level of dietary cholesterol increased plasma HDL concentrations, whereas polyunsaturated fat minimized the dietary cholesterol-mediated increase. Interactions were also observed for hepatic cholesterol: dietary cholesterol increased both free and esterified hepatic cholesterol concentrations in all groups fed all the dietary fats, and fat type influenced the extent of hepatic cholesterol accumulation. Lard-fed animals accumulated the least hepatic cholesterol over the range of dietary cholesterol intakes. Dietary cholesterol suppressed hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, with maximal suppression at all levels of cholesterol intake. Dietary cholesterol had a greater effect on plasma and hepatic cholesterol concentrations and hepatic HMG-CoA reductase activity than did fat type. The data indicated limited interactions of fat type and cholesterol quantity in altering mechanisms regulating plasma cholesterol homeostasis. |
| Dietary fat type related changes in tissue cholesterol and fatty acid synthesis are influenced by energy intake level in rats Cha, M. C. and P. J. Jones (1997), J Am Coll Nutr 16(6): 592-9. Abstract: OBJECTIVE: To investigate the interaction of dietary fat source and energy intake level on tissue cholesterol and triacylglycerol fatty acid (TG-FA) synthesis. METHODS: Ninety-six rats were randomly divided into 12 groups and fed diets containing fish oil, safflower oil, olive oil or beef tallow, each consumed ad libitum and at 85% and 68% of ad libitum intake for 10 weeks. Cholesterol and TG-FA fractional and absolute synthesis rates in the liver and fractional synthesis rates in the small intestine were determined using deuterium (D) incorporation 2 hours after injecting D2O. RESULTS: Olive oil feeding was associated with higher (p < 0.05) cholesterol and TG-FA synthesis rates in the liver and small intestine compared with other fats. Modifications in cholesterol synthesis by fat type depended on energy intake level. With ad libitum feeding, synthesis rates were lower (p < 0.01) following the safflower oil vs. the olive oil treatment. This effect was not observed in 68% energy restricted animals. However, in the intestine, differences (p < 0.01) in cholesterol synthesis rates between groups fed fish oil and beef tallow ad libitum were not observed with energy restriction. Energy restriction increased (p < 0.05) TG-FA synthesis rates in intestine of fish and safflower oil-fed groups, but not in that of olive oil- and beef tallow-fed animals. CONCLUSIONS: These results demonstrate the possible importance of dietary fat selection to control against hyperlipidemia during consumption of weight-reduction diets. |
| Dietary fat, cholesterol and colorectal cancer in a prospective study Jarvinen, R., P. Knekt, et al. (2001), Br J Cancer 85(3): 357-61. Abstract: The relationships between consumption of total fat, major dietary fatty acids, cholesterol, consumption of meat and eggs, and the incidence of colorectal cancers were studied in a cohort based on the Finnish Mobile Clinic Health Examination Survey. Baseline (1967-1972) information on habitual food consumption over the preceding year was collected from 9959 men and women free of diagnosed cancer. A total of 109 new colorectal cancer cases were ascertained late 1999. High cholesterol intake was associated with increased risk for colorectal cancers. The relative risk between the highest and lowest quartiles of dietary cholesterol was 3.26 (95% confidence interval 1.54-6.88) after adjusting for age, sex, body mass index, occupation, smoking, geographic region, energy intake and consumption of vegetables, fruits and cereals. Consumption of total fat and intake of saturated, monounsaturated, or polyunsaturated fatty acids were not significantly associated with colorectal cancer risk. Nonsignificant associations were found between consumption of meat and eggs and colorectal cancer risk. The results of the present study indicate that high cholesterol intake may increase colorectal cancer risk, but do not suggest the presence of significant effects of dietary fat intake on colorectal cancer incidence. |
| Dietary fats and cholesterol in italian infants and children Agostoni, C., E. Riva, et al. (2000), Am J Clin Nutr 72(5 Suppl): 1384S-1391S. Abstract: The fat intake of Italian infants has peculiar characteristics that begin quite early because their mothers' milk has a monounsaturated fat content (45%) at the upper limit of the values found in Europe. Comparison studies in breast-fed and formula-fed infants were conducted to evaluate growth and developmental correlates and differences in fat intakes in the early months of life. Breast-fed infants have higher blood lipid concentrations at 4 mo of age than do formula-fed infants. The addition of long-chain polyunsaturated fatty acids (LCPUFAs) and cholesterol to formulas for term infants may affect concentrations of circulating blood lipids as well as the LCPUFA composition of the lipids during the breast-feeding period. The addition of LCPUFAs does not seem to affect the growth rate of formula-fed infants. Although an initial benefit of LCPUFA feeding on eye-hand coordination was observed, this effect was not sustained; by 24 mo, different feeding groups had similar developmental scores. Other peculiarities of the Italian experience are presented, including body weights from infancy to early childhood in 147 children, the nutrient densities of different diets in Italian schoolchildren, and the effects of nutritional education on dietary intakes. The diets of these children were high in animal protein and supplied approximately 30-35% of energy from fats throughout childhood. Both the dietary protein intakes at 1 y of age and parental body mass indexes were associated with 5-y body mass index values. Classroom education may be useful to lower the plasma lipid concentrations in healthy, primary school-age children. It is not known whether this early modification can be maintained and whether it influences the later development of cardiovascular disorders. |
| Dietary fats modulate age-dependent effects of dietary proteins on cholesterol metabolism in rats Choi, Y. S., I. Ikeda, et al. (1990), J Nutr Sci Vitaminol (Tokyo) 36 Suppl 2: S181-4. Abstract: Different aged male rats, 4 weeks or 9 months old, were fed diets containing either casein (CAS), milk whey protein (WHY) or soybean protein (SOY) with corn oil or sardine oil for 4 weeks. The hypocholesterolemic effect of SOY, compared to CAS, was more evident in rats fed corn oil than in those fed sardine oil, and in young rats than in adult rats, irrespective of dietary cholesterol. In contrast, the liver cholesterol-lowering effect of SOY was more marked in adult than in young rats in all experiments. WHY exerted an intermediate effect on the concentration of liver cholesterol. At both ages, the response of liver 3-hydroxy-3-methylglutaryl (HMG) CoA reductase activity was diverse and dependent upon the source of dietary fat and age of the animal. Fecal steroid excretion was significantly higher in rats fed SOY than in those fed either CAS or WHY, especially in adult rats. The results showed a diverse interaction of the protein type, fat and age in respect to lipid metabolism. |
| Dietary fats modulate the regulatory potential of dietary cholesterol on cholesterol 7 alpha-hydroxylase gene expression Cheema, S. K., D. Cikaluk, et al. (1997), J Lipid Res 38(2): 315-23. Abstract: Cholesterol 7 alpha-hydroxylase (cyp7) is the rate-limiting enzyme in bile acid biosynthesis. Previously, dietary cholesterol was shown to induce cyp7 gene expression. However, recent studies have produced data that are inconsistent with this observation, suggesting the possibility that other factors in the diet are also important in the regulation of cyp7 by dietary cholesterol. The effect of dietary fats on the ability of dietary cholesterol to regulate cyp7 activity and mRNA abundance was assessed. High fat diets composed primarily of polyunsaturated (PUFA), monounsaturated (MUFA), or saturated (SFA) fatty acids induced hypercholesterolemia regardless of whether cholesterol was present or not. However, the effects of each diet on bile composition and hepatic cholesterol content were variable. Microsomal fatty acid profiles reflected the fatty acid composition of the diets. Addition of cholesterol to the PUFA diet increased cyp7 mRNA abundance and activity, analogous with the results observed in mice fed a chow plus cholesterol diet. On the other hand, addition of cholesterol to diets high in MUFA or SFA caused a significant reduction of cyp7 mRNA abundance and activity. Addition of cholesterol to all the diets caused the expected changes in low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA abundance but was not correlated with the changes in cyp7 mRNA abundance. The relationship between cyp7 mRNA abundance and hepatic total cholesterol content or hepatic microsomal cholesterol content was evident, suggesting that cholesterol status does not necessarily determine cyp7 mRNA abundance. The results of this study illustrate that the type of dietary fat is important in elaborating the regulatory potential of dietary cholesterol on cyp7 gene expression and suggest that the regulation of cyp7 gene expression does not involve the classical sterol-mediated pathway. |
| Dietary fats rich in saturated fatty acids (12:0, 14:0, and 16:0) enhance gallstone formation relative to monounsaturated fat (18:1) in cholesterol-fed hamsters Jonnalagadda, S. S., E. A. Trautwein, et al. (1995), Lipids 30(5): 415-24. Abstract: To test the possibility that dietary palmitic acid (16:0) may be lithogenic, different fats were blended to exchange 18:1 in olive oil with either 16:0 in palm stearin, 12:0 + 14:0 in coconut oil, or 14:0 + 16:0 in butterfat. Dietary 18:2 was held constant at 1.2% energy (en) (with extra safflower oil as needed) in these four purified diets containing low fat (11% of total energy) and 0.4% cholesterol. A fifth, high-fat diet provided 40% of the total energy as the 16:0-rich blend. All hamsters fed the low-fat 16:0-rich blend for six weeks developed cholesterol gallstones (8/8). Although the gallstone incidence was lower for the 12:0 + 14:0-rich diet (5/8), the severity of stone formation in affected hamsters was equal to that in the low-fat, 16:0-rich group. Mucin accumulation in gallbladder bile was often associated with cholesterol gallstones in diets containing 16:0, but was minimal in 18:1-rich and 12:0 + 14:0-rich groups. Neither the lithogenic index (all > 1.0), plasma lipids, nor liver cholesterol was a selective predictor of stone formation. The high-fat, 16:0-rich diet actually decreased cholesterol stone incidence (3/8) and severity, but yielded a high incidence of pigment stones (5/8). Thus, saturated fat and 16:0 per se were not responsible for the exaggerated lithogenesis. Because the antilithogenic 18:1-rich diet also normalized the 18:2 intake (1.2% en) relative to previous butter diets (0.3% en), the potential importance of essential fatty acids (EFA) deficiency in the model was tested in a second study by feeding graded amounts of 18:2 (0.3, 0.6, 0.9, and 1.2% en) as safflower oil in four low-fat, butter-rich diets (11% en as fat) without alleviating gallstone incidence or severity. These studies indicate that substitution of 18:1 for saturated fatty acids in low-fat diets reduces gallstone formation without affecting the lithogenic index. Furthermore, intake of 18:2 at or below the EFA requirement does not appear to be a major factor in this model. |
| Dietary fatty acid modification of HDL phospholipid molecular species alters lecithin: cholesterol acyltransferase reactivity in cynomolgus monkeys Thornburg, J. T., J. S. Parks, et al. (1995), J Lipid Res 36(2): 277-89. Abstract: In the following report, cynomolgous monkeys, fed atherogenic diets containing either saturated, monounsaturated, polyunsaturated (n-6 Poly) or fish oil (n-3 Poly) fat as 35% of total calories, provide a model for the study of dietary fat effects on plasma lipoproteins and atherosclerosis. We have previously described the ability of polyunsaturated fat diets to lower plasma described the ability of polyunsaturated fat diets to lower plasma high density lipoprotein (HDL) cholesterol levels and alter HDL subpopulation distribution in the primate model. These experiments investigate possible mechanisms responsible for such modifications. Animals fed polyunsaturated fat had significantly lower plasma concentrations of HDL cholesterol, total plasma cholesterol, and apolipoprotein A-I. Such changes were reflected in the distribution of protein among HDL subfractions, with the most remarkable modification in subclass distribution being the preponderance of small HDL particles in the n-3 Poly-fed animals. Striking alterations were also observed in the distribution of phosphatidylcholine (PC) molecular species (diet effect P < 0.0001 for all major molecular species). Phosphatidylcholine isolated from lipoproteins were used to make recombinant HDL (rHDL) particles. The reaction rate of purified lecithin:cholesterol acyltransferase (LCAT) with particles made from n-3 Poly-derived PC was 50% of that determined using rHDL formed with PC from other dietary groups (P < 0.0001). When the distribution of LCAT-derived rHDL cholesteryl esters was analyzed, LCAT demonstrated little selectivity for certain PC molecular species except in n-3 Poly-derived rHDL where 18:2-containing PC was selectively utilized. These data demonstrate that differences in dietary fat intake can significantly alter HDL PC concentration and molecular species distribution. We suggest that diet-induced alterations in HDL PC molecular species modify the type of cholesteryl esters produced during the LCAT reaction thereby affecting the plasma cholesteryl ester pool. We also propose that dietary n-3 Poly affects cholesteryl ester metabolism in part via LCAT by lowering PC (LCAT substrate) availability, altering the rate of the LCAT reaction, and decreasing HDL cholesterol concentrations; however, n-6 Poly dietary fat effects on HDL concentration appear to be through some mechanism other than LCAT. |
| Dietary fatty acids and cholesterol differentially modulate HDL cholesterol metabolism in Golden-Syrian hamsters Dorfman, S. E., S. Wang, et al. (2005), J Nutr 135(3): 492-8. Abstract: Dietary fatty acids alter HDL cholesterol concentrations, presumably through mechanisms related to reverse cholesterol transport. The effect of dietary fats (coconut oil, butter, traditional stick margarine, soybean oil, canola oil) differing in fatty acid profile on this antiatherogenic process was assessed with respect to plasma lipids; exogenous and endogenous lecithin-cholesterol acyltransferase (LCAT), cholesterol ester transfer protein (CETP), phospholipid transfer protein (PLTP) activities; and LCAT, apolipoprotein (apo) A-I and scavenger receptor B class-1 (SR-B1) mRNA abundance. Golden-Syrian hamsters were fed a nonpurified (6.25 g/100 g fat) diet containing an additional 10 g/100 g experimental fat and 0.1 g/100 g cholesterol for 6 wk. Canola and soybean oils significantly lowered serum HDL cholesterol concentrations relative to butter. Canola oil, relative to butter, resulted in higher exogenous LCAT activity, and both soybean and canola oils significantly increased hepatic apo A-I and SR-B1 mRNA abundance. Butter, relative to margarine, coconut and soybean oils, significantly increased serum non-HDL cholesterol concentrations. Endogenous and exogenous LCAT, CETP, and PLTP activities did not differ in hamsters fed margarine or saturated fat diets, despite lower hepatic LCAT, apo A-I, and SR-B1 mRNA abundance, suggesting that changes in available substrate and/or modification to the LCAT protein may have been involved in lipoprotein changes. These results suggest that lower HDL cholesterol concentrations, as a result of canola and soybean oil feeding, may not be detrimental due to increases in components involved in the reverse cholesterol transport process in these hamsters and may retard the progression of atherosclerosis. |
| Dietary fatty acids and cholesterol in the first 2 years of life Agostoni, C. and E. Riva (1998), Prostaglandins Leukot Essent Fatty Acids 58(1): 33-7. Abstract: Both long-chain polyunsaturated (LCP) fatty acids and cholesterol are supplied by human milk. Dietary long-chain polyunsaturated fatty acids in the first 2 years of life have been associated with growth and developmental indices. Cholesterol supply does not seem relevant for structural purposes, but could have a role in the metabolism of LCP. Complex relationships between dietary fatty acids and cholesterol seem to be major determinants of blood lipid levels in the first months of life. Data from both suckling and weaned infants indicate that their blood lipid profile reacts to changes in their diet in a manner similar to adults. Early intervention trials on weaned infants (<2 years of age) have been addressed in populations at high risk for early cardiovascular disorders and seem safe for growth at short-term assessments, but the balance of all the macronutrients should be carefully considered. While the effects of plasma cholesterol concentrations in the suckling infant on the subsequent development of atheroslerosis are still unknown, both the diet composition and the way by which food is supplied to infants seem to be major determinants of their metabolic profile. |
| Dietary fatty acids and dietary cholesterol differ in their effect on the in vivo regulation of apolipoprotein A-I and A-II gene expression in inbred strains of mice Srivastava, R. A., J. Tang, et al. (1992), Biochim Biophys Acta 1125(3): 251-61. Abstract: Dietary cholesterol and dietary saturated fatty acids affected the plasma concentrations of various HDL components and the hepatic and intestinal expression of the apolipoprotein (apo) A-I gene and the hepatic expression of the A-II gene differently in three inbred strains of female mice. Thus, the HC diet (0.5% cholesterol, no added fatty acids) decreased HDL-cholesterol in C57BL and SWR strains but not in the C3H strain; plasma apo A-I and apo A-II concentrations decreased in all three strains. HDL-C/apo A-I and apo A-I/apo A-II mass ratios increased, suggesting that the HC diet altered both the concentrations and the compositions of HDL particles. In contrast, the HF diet (20% hydrogenated coconut oil, no added cholesterol) increased HDL cholesterol and apo A-I concentrations. The combination diet (HF/C, 20% coconut oil plus 0.5% cholesterol) increased HDL cholesterol and decreased triacylglycerols. Apo A-I concentrations were unaltered except for a significant increase in SWR mice. Apo A-II concentrations decreased in all strains. To examine molecular events that could lead to the changes in plasma apo A-I and apo A-II, we measured transcription rates in hepatic nuclei and steady state mRNA concentrations in liver and intestine and apo A-I synthetic rates in liver. Dietary cholesterol and fatty acids produced differing effects at transcriptional as well as post-transcriptional loci and the changes differed according to mouse strain. The most pronounced strain-related differences for both apo A-I and apo A-II occurred at post-transcriptional loci of apoprotein production. These could represent altered rates of translation in, or secretion from liver and/or intestine, or altered rates of clearance from plasma. In conclusion, the regulation of apo A-I and apo A-II gene expression by diet occurs at several steps of their production and perhaps also in catabolic pathways. This study identifies potential loci of regulation and forms the basis for future studies investigating specific genetic and molecular regulatory mechanisms. |
| Dietary fatty acids and the regulation of plasma low density lipoprotein cholesterol concentrations Dietschy, J. M. (1998), J Nutr 128(2 Suppl): 444S-448S. Abstract: Epidemiologic studies over the past 25 years have shown that the level of dietary fat intake is positively correlated with the average serum cholesterol value and mortality from coronary heart disease (CHD). A number of different investigators demonstrated that in addition to total fat, the fatty acid composition of diets influenced serum total cholesterol (TC) in humans. In general, saturated fatty acids were found to elevate the serum cholesterol concentration, and unsaturated fatty acids were found to decrease this value. The lipoprotein fraction most affected was the level of cholesterol carried in low density lipoprotein (LDL-C). It has now been demonstrated that the steady-state level of LDL-C is predominantly dictated by metabolic events in the liver. As the amount of dietary cholesterol entering the body is increased, there is expansion of the sterol pool in the liver cell and down regulation of LDL receptors (LDLR) that are primarily responsible for clearing LDL-C from the blood stream. When dietary cholesterol intake is kept constant, however, long-chain saturated fatty acids further suppress hepatic LDLR activity, whereas several unsaturated fatty acids have the opposite effect. These regulatory events depend upon the availability of the various fatty acids to shift intracellular cholesterol between a regulatory and storage pool of cholesterol, and this effect is mediated by the enzyme acyl-CoA:cholesterol acyltransferase (ACAT). |
| Dietary fatty acids regulate cholesterol induction of liver CYP7alpha1 expression and bile acid production Li, Y., M. J. Hou, et al. (2005), Lipids 40(5): 455-62. Abstract: In the present study we investigated the effects of dietary fats containing predominantly PUFA, monounsaturated FA (MUFA), or saturated FA (SFA) on lipid profile and liver cholesterol 7alpha-hydroxylase (CYP7alpha1) mRNA expression and bile acid production in C57BL/6J mice. The animals (n = 75) were randomly divided into five groups and fed a basic chow diet (AIN-93G) (BC diet), a chow diet with 1 g/100 g of cholesterol (Chol diet), a chow diet with 1 g/100 g of cholesterol and 14 g/100 g of safflower oil (Chol + PUFA diet), a chow diet with 1 g/100 g of cholesterol and olive oil (Chol + MUFA diet), or a chow diet with 1 g/100 g of cholesterol and myristic acid (Chol + SFA diet) for 6 wk. The results showed that the Chol + SFA diet decreased CYP7alpha1 gene expression and bile acid pool size, resulting in increased blood and liver cholesterol levels. Addition of PUFA and MUFA to a 1% cholesterol diet increased the bile acid pool production or bile acid excretion and simultaneously decreased liver cholesterol accumulation despite decreased CYP7alpha1 mRNA expression. The results indicate that the decreased bile acid pool size induced by the SFA diet is related to inhibition of the liver CYP7alpha1 gene expression, but an increased bile acid pool size and improved cholesterol homeostasis are disassociated from the liver CYP7alpha1 gene expression. |
| Dietary fatty acids, cholesterol, and the lipoprotein profile Hayes, K. C. (2000), Br J Nutr 84(4): 397-9. |
| Dietary fiber for reducing blood cholesterol Lipsky, H., M. Gloger, et al. (1990), J Clin Pharmacol 30(8): 699-703. Abstract: Soluble dietary fiber, including psyllium, has been shown to have mild to modest cholesterol lowering properties. Psyllium hydrophilic mucilloid (Metamucil, Procter and Gamble, Cincinnati, OH), a bulk laxative, when used as a dietary supplement in combination with a low fat diet, can lower total serum cholesterol and low-density lipoprotein (LDL) cholesterol, and raise high-density lipoprotein (HDL) cholesterol in hypercholesterolemic patients. The cholesterol lowering effects of psyllium are much less evident than those observed with cholestyramine and the HMG-CoA reductase inhibitors. The mechanism for the cholesterol lowering effect of psyllium is not known. The substance is well tolerated with long-term use. |
| Dietary fiber in industrial tomato residue and its effects on glycaemic response and seric cholesterol in rats Alvarado, M., E. Pacheco-Delahaye, et al. (1999), Arch Latinoam Nutr 49(2): 138-42. Abstract: The left over after ketchup sauce is obtained is a tomato residue (RIT) that contains skin and seeds. Proximal analysis of the flour of this industrial product reveals that it has 50% dietary fiber, 18% protein and 10% fat. Due to the high dietary fiber content the effect on glucose absorption and seric cholesterol was studied. Sprague-Dawley rats were given an intragastric meal after a 12 hours fast containing 263 g tomato residue flour (RIT)/diet or a control meal (0% RIT) and glucose plasma levels were determined. Results show that the presence of RIT in the test meal flattened glucose response curves. Ad lib administration of four diets differing in RIT content to four groups of rats for 18 days showed that although animals on a high RIT diet ate increased amounts of cholesterol the plasma lipid levels remained constant which suggest that the presence of RIT fibre on the diet is responsible for this effect. The results reported in this paper suggest that the dietary fiber of RIT diminishes glucose absorption and reduces seric cholesterol levels, which in turn could be useful in the treatment of NIDD and hypercholesterolaemic patients. |
| Dietary fiber sources lower blood cholesterol in C57BL/6 mice Hundemer, J. K., S. P. Nabar, et al. (1991), J Nutr 121(9): 1360-5. Abstract: Five sources of dietary fiber were compared for their effect on blood and liver cholesterol. The effects of soybean fiber, rice bran (full fat), oat bran, barley bran and mixed bran on total blood cholesterol concentrations and liver cholesterol concentrations were measured in beef-fed C57BL/6 male mice. Each diet contained cooked beef, beef tallow, corn starch and 7% dietary fiber from one of the five fiber sources. A control group consumed a fiber-free diet. Dietary cholesterol was provided by the beef and beef tallow only. The experimental diets were fed for 3 wk; blood and liver were collected when the mice were 18 wk old. The liver cholesterol concentration in the rice bran-fed group was the lowest of the six diet groups and was significantly different than concentrations in the oat bran-fed group and the barley bran-fed group (P less than 0.05). The oat bran, mixed bran, and barley bran did not significantly lower blood cholesterol in the mice. Both the soybean fiber and rice bran diet groups had significantly lower total blood cholesterol than did the fiber-free controls (P less than 0.05). The soybean fiber group also had significantly lower blood cholesterol than the mixed-bran group. |
| Dietary fibres reduce blood pressure, serum total cholesterol and platelet aggregation in rats Bagger, M., O. Andersen, et al. (1996), Br J Nutr 75(3): 483-93. Abstract: The effects of dietary fat and dietary fibres on blood pressure, serum lipids and platelet aggregation in spontaneously hypertensive and Wistar-Kyoto rats have been investigated. The systolic and diastolic blood pressure values were increased with increasing amounts of dietary fat and normalized by dietary fibre supplementation. The greatest reduction in blood pressure was obtained by a combination of reduced dietary fat and supplementary dietary fibre. Addition of dietary fibre when the amount of dietary fat was high or reduction of dietary fat when the amount of dietary fibre was low gave a smaller effect. In both rat strains the decreases in systolic and diastolic blood pressure values after reducing dietary fat and/or increasing dietary fibre were about 10-15 mmHg. Serum total cholesterol and serum HDL-cholesterol concentrations were reduced by reduction of dietary fat or a combination of dietary fat reduction and dietary fibre addition. A combination of dietary fat reduction and dietary fibre addition was the most effective dietary change for reducing serum triacylglycerol concentration and platelet aggregation. The present study demonstrates that in this experimental model it is possible to reduce risk indicators of coronary heart disease significantly by changing dietary habits. |