Changes In Dietary Cholesterol Research Articles

Meta-regression analysis of the effects of dietary cholesterol intake on LDL and HDL cholesterol

Elevated low-density lipoprotein (LDL) cholesterol is a major risk factor for cardiovascular disease. Dietary guidance recommends reducing saturated fatty acid, trans fatty acid, and cholesterol intakes to reduce circulating LDL cholesterol. Cholesterol intake may also affect high-density lipoprotein (HDL)-cholesterol concentrations, but its impact has not been fully quantified. The aims of this study were to investigate the dose-response relation between changes in dietary cholesterol intake and changes in lipoprotein-cholesterol markers for cardiovascular disease risk and to provide a reference for clinicians on how changes in dietary cholesterol intake affect circulating cholesterol concentrations, after accounting for intakes of fatty acids. We used a Bayesian approach to meta-regression analysis, which uses Markov chain Monte Carlo techniques, to assess the relation between the change in dietary cholesterol (adjusted for dietary fatty acids) and changes in LDL and HDL cholesterol based on the use of data from randomized dietary intervention trials. Fifty-five studies (2652 subjects) were included in the analysis. The nonlinear Michaelis-Menten (MM) and Hill models best described the data across the full spectrum of dietary cholesterol changes studied (0-1500 mg/d). Mean predicted changes in LDL cholesterol for an increase of 100 mg dietary cholesterol/d were 1.90, 4.46, and 4.58 mg/dL for the linear, nonlinear MM, and Hill models, respectively. The change in dietary cholesterol was positively associated with the change in LDL-cholesterol concentration. The linear and MM models indicate that the change in dietary cholesterol is modestly inversely related to the change in circulating HDL-cholesterol concentrations in men but is positively related in women. The clinical implications of HDL-cholesterol changes associated with dietary cholesterol remain uncertain.

Effects of cholesterol on growth, feed utilization, body composition and immune parameters in juvenile oriental river prawn,Macrobrachium nipponense(De Haan)

An 8-week feeding trial was conducted to investigate the effects of dietary cholesterol levels on growth, feed utilization, body composition and immune parameters in juvenile oriental river prawn, Macrobrachium nipponense. Six isolipid (80 g kg−1 crude lipid) and isoproteic (400 g kg−1 crude protein) diets, supplemented with 0, 3.0, 6.0, 9.0, 12.0 and 15.0 g kg−1 cholesterol, were evaluated. Growth performance and feed utilization of M. nipponense were improved as dietary cholesterol levels increased. Weight gain and specific growth rate were highest, and feed conversation ratio was lowest, when prawns were fed a diet supplemented with 9.0 g kg−1 cholesterol. However, final body weights and survival rates of juvenile M. nipponense were not affected significantly by dietary cholesterol. Body composition of prawns, including moisture, crude protein and crude lipid, was not significantly affected by changes in dietary cholesterol. The immune parameters measured in hepatopancreas, including total antioxidant capacity, and glutathione, catalase, alkaline phosphatase and acid phosphatase activities, were at optimum levels in prawns fed with 9.0 g kg−1 dietary cholesterol. In summary, the best growth performance, lowest feed conversation ratio, and the most enhanced antioxidant capacity and immunity parameters were attained in juvenile M. nipponense when fed a diet supplemented with 9.0 g kg−1 cholesterol.

The Amount of Dietary Cholesterol Changes the Mode of Effects of (n-3) Polyunsaturated Fatty Acid on Lipoprotein Cholesterol in Hamsters

This study was designed to investigate the effects of the interaction between dietary (n-3) polyunsaturated fatty acids (PUFA) and different dietary cholesterol content on plasma and liver cholesterol in hamsters. Male Syrian hamsters consumed diets containing an incremental increase in dietary cholesterol content (0, 0.025, 0.05, 0.1 and 0.2%, w/w) with either (n-3) PUFA (21 g/100 g fatty acids) or (n-6) PUFA (37.4 g/100 g fatty acids) fat for 6 weeks. In hamsters fed the nonatherogenic diet (0 or 0.025% dietary cholesterol), very low density lipoprotein (VLDL)-cholesterol levels in the (n-3) PUFA group were not significantly different from those in the (n-6) PUFA group, and low density lipoprotein (LDL)-cholesterol levels in the (n-3) PUFA group were significantly lower than those in the (n-6) PUFA group. In contrast, in hamsters fed the atherogenic diet (0.1 or 0.2% dietary cholesterol), VLDL- and LDL-cholesterol levels in the (n-3) PUFA group were significantly higher than those in the (n-6) PUFA group, in a dose-dependent manner. When the hamsters were fed with 0, 0.025, 0.05, 0.1 or 0.2% (w/w) dietary cholesterol, high density lipoprotein (HDL) cholesterol concentration was significantly lower in the (n-3) PUFA group than those in the (n-6) PUFA group. Hepatic cholesteryl esters were significantly lower, while hepatic microsomal acyl-coenzyme A:cholesterol acyltransferase activity and VLDL-cholesteryl esters were significantly higher in hamsters fed (n-3) PUFA with the atherogenic diet (0.1 or 0.2% dietary cholesterol) than in those fed (n-6) PUFA with the atherogenic diet. Our results demonstrate that the amount of dietary cholesterol is an important factor in determining the mode and extent of effects of dietary (n-3) PUFA, especially on VLDL- and LDL-cholesterol levels. When dietary cholesterol intake was above 0.1% (w/w), the plasma cholesterol-lowering effect of (n-3) PUFA disappeared, and instead, it showed a cholesterol-increasing effect. However, the effects of dietary (n-3) PUFA on HDL-cholesterol are independent of dietary cholesterol content.

The Impact of Egg Limitations on Coronary Heart Disease Risk: Do the Numbers Add Up?

For over 25 years eggs have been the icon for the fat, cholesterol and caloric excesses in the American diet, and the message to limit eggs to lower heart disease risk has been widely circulated. The “dietary cholesterol equals blood cholesterol” view is a standard of dietary recommendations, yet few consider whether the evidence justifies such restrictions. Over 50 years of cholesterol-feeding studies show that dietary cholesterol does have a small effect on plasma cholesterol concentrations. The 167 cholesterol feeding studies in over 3,500 subjects in the literature indicate that a 100 mg change in dietary cholesterol changes plasma total cholesterol by 2.2 mg/dL.Today we recognize that dietary effects on plasma cholesterol must be viewed from effects on the atherogenic LDL cholesterol as well as anti-atherogenic HDL cholesterol since the ratio of LDL:HDL cholesterol is a major determinant of heart disease risk. Cholesterol feeding studies demonstrate that dietary cholesterol increases both LDL and HDL cholesterol with little change in the LDL:HDL ratio. Addition of 100 mg cholesterol per day to the diet increases total cholesterol with a 1.9 mg/dL increase in LDL cholesterol and a 0.4 mg/dL increase in HDL cholesterol. On average, the LDL:HDL ratio change per 100 mg/day change in dietary cholesterol is from 2.60 to 2.61, which would be predicted to have little effect on heart disease risk. These data help explain the epidemiological studies showing that dietary cholesterol is not related to coronary heart disease incidence or mortality across or within populations.

Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a meta-analysis

Quantitative relations between dietary fat and cholesterol and plasma lipid concentrations have been the subject of much study and some controversy during the past 40 y. Previous meta-analyses have focused on the most tightly controlled, highest-quality experiments. To test whether the findings of these investigations are generalizable to broader experimental settings and to the design of practical dietary education interventions, data from 224 published studies on 8143 subjects in 366 independent groups including 878 diet-blood lipid comparisons were subjected to weighted multiple-regression analysis. Inclusion criteria specified intervention studies published in English between 1966 and 1994 reporting quantitative data on changes in dietary cholesterol and fat and corresponding changes in serum cholesterol, triacylglycerol, and lipoprotein cholesterol concentrations. Regression models are reported for serum total cholesterol, triacylglycerol, and low-density-high-density-, and very-low-density-lipoprotein cholesterol, with multiple correlations of 0.74, 0.65, 0.41, 0.14, and 0.34, respectively. Interactions of dietary factors, initial dietary intakes and serum concentrations, and study and subject characteristics had little effect on these models. Predictions indicated that compliance with current dietary recommendations (30% of energy from fat, < 10% from saturated fat, and < 300 mg cholesterol/d) will reduce plasma total and low-density-lipoprotein-cholesterol concentrations by approximately 5% compared with amounts associated with the average American diet.

Dietary cholesterol and the optimal diet for reducing risk of atherosclerosis: D.J. McNamara. Lipid Metabolism Laboratory, University of Arizona, Tuczon, AZ. Can J Cardiol 1995;11(Suppl. G):123G–6G

The importance of dietary cholesterol in the incidence of hypercholesterolemia in the population remains a topic of scientific debate. Analysis of the results from over 30 years of cholesterol feeding studies (n = 128) in more than 2750 patients indicate that for the majority of individuals modest changes in dietary cholesterol have little if any effect on plasma lipoprotein cholesterol levels. Data demonstrate that on average a change in cholesterol intake of 100 mg/day results in a change in plasma total cholesterol of 0.07 mmol/L (2.5 mg/dL). The studies also show that the extent of response to dietary cholesterol is independent of the amount of dietary fat and of the baseline plasma cholesterol level. In contrast, the dose adjusted plasma cholesterol response to a dietary cholesterol challenge is affected by the type of dietary fat and the baseline dietary cholesterol intake. Based on these data a reduction in dietary cholesterol intake from 450 to 300 mg/day will, on average, lower plasma cholesterol levels by 0.10 mmol/L (3.7 mg/dL). This decrease is modest and highly variable due to significant interindividual heterogeneity of responses. It is estimated that one-third of the population is sensitive to dietary cholesterol whereas two-thirds are resistant to plasma cholesterol changes. In comparison, a 1% decrease in energy intake from saturated fat decreases plasma cholesterol 0.08 mmol/L (3 mg/dL). Consumption of products marketed as 'No cholesterol' with high total and saturated fat clearly does not contribute to the optimal diet for reducing plasma cholesterol levels of risk of atherosclerosis.

Gene-diet interaction in determining plasma lipid response to dietary intervention

It has long been known that there is an extremely high degree of variability in both human and nonhuman primates in terms of low density lipoprotein cholesterol (LDL-C) lowering in response to restriction of dietary saturated fat and cholesterol. In this regard we have reviewed the current knowledge regarding the gene-diet interaction in relation to plasma lipid response to dietary intervention. Several candidate gene loci have been examined in humans: apolipoprotein (apo) A-I, apo A-IV, apo B, apo C-111 and apo E, as well as lipoprotein lipase (LPL). Several mutations at these loci have been found to be associated with responsiveness. We and others have documented that subjects carrying the apo E4 allele are more responsive with regard to LDL-C lowering in response to dietary fat and cholesterol restriction than subjects carrying the apo E3 or apo E2 alleles, whereas some studies report no association of apo E phenotypes with lipid response to some dietary interventions. Our own meta-analysis indicates that apo E genotype effects are modulated via alterations of amount and type of dietary fat. We have also documented that subjects carrying the common glutamine for histidine mutation at amino acid 360 of apo A-IV are significantly less responsive in terms of LDL-C lowering than subjects with the normal apo A-IV allele. These findings have been confirmed by other investigators. The data suggest that the effect of apo A-IV genotype is modulated via changes in dietary cholesterol. In addition, we have documented that the common G/A mutation within the promoter region of the apo A-I gene is associated with greater responsiveness of LDL-C to dietary fat alterations. The XbaI and insertion/deletion polymorphisms at the apo B gene locus and the HindIIl restriction fragment length polymorphism (RFLP) at the LPL locus have also been associated with diet responsiveness. Therefore, in humans these gene loci account for a significant portion of the variability in plasma lipid response to dietary alterations.

Dietary factors relate to cardiovascular risk factors in early life. Bogalusa Heart Study.

Relationships between diet and cardiovascular disease risk factors were studied in a cohort of infants in Bogalusa, Louisiana. The 24-hour dietary recalls and cardiovascular measurements were obtained on each child at age 6 months, yearly through age 4, and again at age 7 (cardiovascular measurements only). At ages 4 and 7, children with persistently high intakes of dietary cholesterol (three or more measurements in the upper tertile) had levels of serum total cholesterol approximately 14 mg/dl higher than children whose intakes of cholesterol were not persistently high. Children in the upper tertile for dietary cholesterol had levels of low density lipoprotein cholesterol (15 mg/dl at age 4 and 18 mg/dl at age 7) higher than children in the lower tertile for dietary cholesterol. Children with high intakes of animal fat were 2 to 6 kg heavier (p less than 0.05) than those with lower intakes. Changes in dietary cholesterol correlated significantly with changes in serum total cholesterol (r = 0.42) and low density lipoprotein cholesterol (r = 0.50) from 6 months to 4 years of age. Changes in subscapular skinfold measurements correlated significantly with changes in intake of total protein (r = 0.31), total fat (r = 0.25), starch (r = 0.31), and energy (r = 0.39) from ages 6 months to 4 years. Results indicate that tracking of dietary components and their relationships with cardiovascular disease risk factors can be detected at an early age. These findings may well be the groundwork for later studies of obesity and the early onset of hyperlipoproteinemia.

Body weight, diet, and serum cholesterol in 871 middle-aged men during 10 years of follow-up (the Zutphen Study)

Information about anthropometric, dietary variables and serum cholesterol was collected in the Zutphen Study in 1960, 1965, and 1970. Relationships among those variables were analyzed both cross-sectionally and longitudinally. In all 3 yr significant correlations were observed between body weight and serum cholesterol. Serum cholesterol was also significantly inversely related to energy intake per kg body weight in all 3 yr after both univariate and multivariate analyses. The percentage energy intake from alcohol was significantly positively related to serum cholesterol in all 3 yr after univariate analyses and in 2 of the 3 yr after multivariate analyses. Changes in body weight during 5 and 10 yr of follow-up were strongly positively related to changes in serum cholesterol during those periods. Multivariate analyses showed that a change of 1 kg in body weight was accompanied by a change in serum cholesterol of 2 mg/dl. Changes in dietary cholesterol per 1000 kcal were weakly significantly related to changes in serum cholesterol during 10 yr of follow-up.

Changes in plasma lipid and lipoprotein fractions after alteration in dietary cholesterol, polyunsaturated, saturated, and total fat in free-living normal and hypercholesterolemic children

To assess the effects of dietary cholesterol and the amount and type of fat on plasma lipid and lipoproteins, nutrient intakes were altered sequentially over 15 months in 11 normal children and 12 children with heterozygous familial hypercholesterolemia. After a 3-month base-line assessment period, on an ad libitum diet, the following diets were given sequentially for three months each: dietary cholesterol greater than 450 mg/day, total fat less than 35% of total calories, and polyunsaturated fat to saturated fat ratio (P/S) greater than 1.5 (diet 1); dietary cholesterol less than 160 mg/day, total fat less than 35% total calories and P/S greater than 1.5 (diet 2); dietary cholesterol less than 160 mg/day, total fat 40% total calories P/S = 1 (diet 3), and dietary cholesterol greater than 450 mg/day total fat greater than 40% total calories, P/S less than 0.04 (diet 4). In normal and familial hypercholesterolemic children the high dietary P/S ratio lowered total and low-density lipoprotein cholesterol in the presence of high dietary cholesterol; sharp reductions in dietary cholesterol lowered the total and low-density lipoprotein cholesterol slightly in familial hypercholesterolemia subjects when P/S was high. High-density lipoprotein cholesterol was not affected by large changes in dietary cholesterol or amount or type of fat. Sustained dietary alteration which significantly lowers total and low-density lipoprotein cholesterol with commercially available products is achievable and practical in free-living children.

Influence of Dietary Cholesterol and Fat on Serum Lipids in Men

The effect of changes in dietary cholesterol and fat on serum lipids was studied in 32 healthy men (mean age = 24.8 years). Subjects were fed a controlled diet for 10 days providing 42 to 45% of the total calories from fat, a P/S ratio of 0.3 to 0.5 and two eggs per day. During the next eight weeks, 16 subjects received each of the following diets for four weeks in a crossover design: 1) a control diet with two eggs per day or 2) the control diet with eggs replaced by a cholesterol-free egg substitute. The remaining 16 subjects received each of the following diets in a similar crossover design: 1) a modified-fat diet containing 35% of the total calories from fat, a P/S ratio ≥ 1.0 and two eggs per day or 2) the same modified-fat diet with the egg substitute replacing the eggs. The two-week cycle of menus repeated throughout the study included a wide variety of foods commonly consumed in this country. Although the response of individual subjects varied, analysis of variance showed a significant decrease in serum total cholesterol related to replacement of eggs with the egg substitute and to modification in the type and amount of dietary fat. A significant diet-treatment interaction or sequencing effect was not found. Change in cholesterol intake related to addition or deletion of two eggs in the daily diet had no significant effect on serum triglycerides, high density lipoprotein cholesterol, or relative lipoprotein concentrations.serum lipids dietary cholesterol dietary fat

Influence of Dietary Cholesterol on Mitochondrial Function in the Rat

Rat-liver mitochondrial cholesterol ester levels were increased nine-fold and free cholesterol levels were doubled by feeding 10% lard and 2% cholesterol with Purina rabbit chow pellets to weanling male Sprague-Dawley rats for 5 weeks. This resulted in depression of State 3 (ADP-stimulated) glutamate respiration and reduced sensitivity to inhibition of phosphyorylation by tetrabutylammonium bromide and oligomycin. Brain, heart, lung, spleen, kidney and testis mitochondrial functions were not responsive to changes in dietary cholesterol nor were increases noted in free cholesterol content; mitochondrial cholesterol esters in these six tissues remained at extremely low levels regardless of treatment. Inclusion of 0.01% oleyl-p-decylbenzene sulfonate (a hypocholesterolemic agent) in the 10% lard and 2% cholesterol diet prevented elevation of rat-liver cholesterol esters and restored "normal" mitochondrial functions of respiratory control. This compound had no lowering effect on the raised level of liver mitochondrial free cholesterol nor on the reduced mitochondrial sensitivity to the phosphorylation inhibitors. We concluded that cholesterol esters were associated with depression of liver mitochondrial respiratory control and that free cholesterol was related to desensitization of mitochondria to the phosphorylation inhibitors.

Dependence of the effects of dietary cholesterol and experimental conditions on serum lipids in man III. The effect on serum cholesterol of removal of eggs from the diet of free-living habitually egg-eating people

Forty-four healthy free living volunteers were used to study the effect of the removal of eggs from a habitual egg-rich diet. The subjects, recruited by advertising, normally consumed at least 1 egg per day. During the 3-week experimental period they were not allowed to eat any eggs or products containing large amounts of eggs, except cakes and tarts. Elimination of eggs from a habitual egg-rich diet did result in a small but significant decrease in serum cholesterol levels in all subjects. No correlation could be demonstrated between changes in serum cholesterol levels and the age of the subjects and between changes in serum cholesterol levels and the numbers of eggs eaten per week before the experimental period. A significant negative correlation was found between changes in serum cholesterol levels and the Quételet index for obesity and between changes in serum cholesterol levels and the serum cholesterol levels before the experimental period. The results indicate that a very variable response is present in a human population toward dietary cholesterol. More research seems to be necessary to describe and select the population of hyperresponders, the subjects who are more sensitive to changes in dietary cholesterol, and the hyporesponders. The results moreover indicate that effects of dietary changes in a free-living population are much smaller than can be accomplished in populations under controlled conditions.

Quantitative Estimation of Diets to Control Serum Cholesterol

The serum cholesterol responses of men to alterations of the fatty acid and cholesterol composition of their diets have been described by previously published, empirical equations derived from data on groups of middle-aged men, under metabolic ward conditions. A nomograph is here presented, constructed from these equations, to facilitate the estimation of serum cholesterol changes to be expected from specific fatty acid and dietary cholesterol changes. The nomograph can also be used to estimate dietary lipid changes required to effect a predetermined serum cholesterol change. A listing of foods is given, with lipid compositions in additive units, such that daily intakes can be readily computed and either applied directly to the nomograph or derived from it. This material is communicated as an interim tool for the approximate prediction of dietary and serum cholesterol changes, and for evaluation and eventual improvement of predictive accuracy.