Changes in atherogenic dyslipidemia induced by carbohydrate restriction in men are dependent on dietary protein source

Previous studies have shown that multiple features of atherogenic dyslipidemia are improved by replacement of dietary carbohydrate with mixed sources of protein and that these lipid and lipoprotein changes are independent of dietary saturated fat content. Because epidemiological evidence suggests that red meat intake may adversely affect cardiovascular disease risk, we tested the effects of replacing dietary carbohydrate with beef protein in the context of high- vs. low-saturated fat intake in 40 healthy men. After a 3-wk baseline diet [50% daily energy (E) as carbohydrate, 13% E as protein, 15% E as saturated fat], participants consumed for 3 wk each in a randomized crossover design two high-beef diets in which protein replaced carbohydrate (31% E as carbohydrate, 31% E as protein, with 10% E as beef protein). The high-beef diets differed in saturated fat content (8% E vs. 15% E with exchange of saturated for monounsaturated fat). Two-week washout periods were included following the baseline diet period and between the randomized diets periods. Plasma TG concentrations were reduced after the 2 lower carbohydrate dietary periods relative to after the baseline diet period and these reductions were independent of saturated fat intake. Plasma total, LDL, and non-HDL cholesterol as well as apoB concentrations were lower after the low-carbohydrate, low-saturated fat diet period than after the low-carbohydrate, high-saturated fat diet period. Given our previous observations with mixed protein diets, the present findings raise the possibility that dietary protein source may modify the effects of saturated fat on atherogenic lipoproteins.     

High carbohydrate and high monounsaturated fatty acid diets similarly affect LDL electrophoretic characteristics in men who are losing weight

We compared the effects of ad libitum consumption of a defined high complex carbohydrate (CHO) diet (% of energy: CHO, 58.3; fat, 25.8) vs. a defined high monounsaturated fatty acid (MUFA) diet (% of energy: CHO, 44.7; fat, 40.1; MUFA, 22.5) on LDL electrophoretic characteristics. Healthy men [n = 65; age, 37.5 +/- 11.2 (mean +/- SD) y; BMI, 29.2 +/- 4.9 kg/m2] were randomly assigned to one of the two diets that they consumed for 6-7 wk. The high CHO diet significantly reduced body weight (-2%). The diet-induced reduction in plasma LDL cholesterol (C) levels in the high-CHO diet group was due mainly to concurrent reductions in the cholesterol content of small (<25.5 nm, P < 0.01) and medium-sized LDL (25.5-26.0 nm, P = 0.01). The high MUFA diet also reduced body weight, and LDL-C and LDL-apolipoprotein (apo)B levels, which were comparable to those in the high CHO group. The cholesterol levels of small LDL particles tended to be reduced (P = 0.24) in the high MUFA group (-12%), similar to changes in the high CHO group. These results suggest that, when associated with weight loss, ad libitum consumption of high CHO and high MUFA diets may be considered to be equally beneficial for the management of LDL-related atherogenic dyslipidemia. However, the high MUFA diet more favorably affected triglyceride levels, suggesting that it may be preferable to a high CHO diet in cardiovascular disease prevention.     

A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men

Very low-carbohydrate (ketogenic) diets are popular yet little is known regarding the effects on serum biomarkers for cardiovascular disease (CVD). This study examined the effects of a 6-wk ketogenic diet on fasting and postprandial serum biomarkers in 20 normal-weight, normolipidemic men. Twelve men switched from their habitual diet (17% protein, 47% carbohydrate and 32% fat) to a ketogenic diet (30% protein, 8% carbohydrate and 61% fat) and eight control subjects consumed their habitual diet for 6 wk. Fasting blood lipids, insulin, LDL particle size, oxidized LDL and postprandial triacylglycerol (TAG) and insulin responses to a fat-rich meal were determined before and after treatment. There were significant decreases in fasting serum TAG (-33%), postprandial lipemia after a fat-rich meal (-29%), and fasting serum insulin concentrations (-34%) after men consumed the ketogenic diet. Fasting serum total and LDL cholesterol and oxidized LDL were unaffected and HDL cholesterol tended to increase with the ketogenic diet (+11.5%; P = 0.066). In subjects with a predominance of small LDL particles pattern B, there were significant increases in mean and peak LDL particle diameter and the percentage of LDL-1 after the ketogenic diet. There were no significant changes in blood lipids in the control group. To our knowledge this is the first study to document the effects of a ketogenic diet on fasting and postprandial CVD biomarkers independent of weight loss. The results suggest that a short-term ketogenic diet does not have a deleterious effect on CVD risk profile and may improve the lipid disorders characteristic of atherogenic dyslipidemia.     

Lack of efficacy of a food-frequency questionnaire in assessing dietary macronutrient intakes in subjects consuming diets of known composition

BACKGROUND: We compared the validity of a semiquantitative food-frequency questionnaire in assessing intakes of macronutrients (absolute amounts and percentages of energy) by 19 subjects fed natural-food diets of known composition. In small subsets (n = 5 or 6), we also tested 3-d diet records. OBJECTIVE: The objective of this study was to investigate the efficacy of food-frequency questionnaires and diet records in subjects fed natural-food diets of known composition. DESIGN: Each subject consumed 3 different diets for >/=6 wk and self-reported his or her food intake by using a food-frequency questionnaire and a diet record. The diets varied in their chemically analyzed contents of fat (15-35% energy), saturated fat (5-14%), monounsaturated fat (5-14.5%), polyunsaturated fat (2.5-10.5%), carbohydrate (49-68%), and cholesterol (108-348 mg/d). RESULTS: The food-frequency questionnaire significantly underestimated fat, saturated fat, monounsaturated fat, and protein intakes and significantly overestimated carbohydrate intake with the high-fat diet. The percentage of energy from fat was significantly underestimated for the high-fat diet and significantly overestimated for the very-low-fat diet. Estimates from the food-frequency questionnaire differed significantly from actual intakes for fat (absolute and percentage), saturated fat (absolute and percentage), monounsaturated fat (absolute and percentage), and protein (percentage) in the high-fat diet and for polyunsaturated fat (absolute and percentage), saturated fat (percentage), fiber (absolute), and cholesterol (daily absolute; in mg/d) in the lower-fat diet. Estimates from the diet records better agreed with actual intakes than did estimates from the food-frequency questionnaire except for monounsaturated fat (absolute and percentage) in the high-fat diet and polyunsaturated fat (percentage) in the lower-fat diet and the very-low-fat diet. CONCLUSION: Our data indicated that the food-frequency questionnaire did not provide reliable estimates of absolute amounts of dietary fats or cholesterol.     

Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women

BACKGROUND: Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight. OBJECTIVE: The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity. DESIGN: A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30-38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints. RESULTS: Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption. CONCLUSION: Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.     

Changes in plasma lipids and other cardiovascular risk factors during 3 energy-restricted diets differing in total fat and fatty acid composition

BACKGROUND: The well-established relation between changes in dietary fatty acids and plasma lipids has been determined in energy-balance states. Whether this relation is altered in states of energy restriction and active weight loss is not clear. OBJECTIVE: The objective of this 12-wk study was to compare the time course of lipid changes and other cardiovascular risk factors in 3 energy-restricted diets (all 6500 kJ) with different total fat and fatty acid compositions. DESIGN: Sixty-two subjects with a body mass index (in kg/m(2)) >24 were stratified into 1 of 3 parallel dietary intervention groups: 1) a very-low-fat (VLF) diet (10% of energy from fat; 3% from saturated fat), 2) a high-saturated-fat (HSF) diet (32% of energy from fat; 17% from saturated fat), and 3) a high-unsaturated-fat (HUF) diet (32% of energy from fat; 6% from saturated fat). RESULTS: After 12 wk, LDL cholesterol decreased by 0. 66 +/- 0.11 (mean +/- SEM) and 0.68 +/- 0.12 mmol/L ( approximately 20%) with the VLF and HUF diets, respectively, compared with a decrease of only 0.24 +/- 0.11 mmol/L (7%) with the HSF diet (P < 0.02 between groups). Diet affected the time course of changes in HDL cholesterol with both high-fat diets, resulting in smaller reductions in HDL cholesterol at weeks 1 (P = 0.0004) and 4 (P = 0.02); however, these differences were no longer apparent by 12 wk. Overall weight loss was 8.6 +/- 0.4 kg (9.7%) and waist circumference decreased by 7.3 +/- 5 cm (8%) for the combined groups, with no significant differences between diets. CONCLUSIONS: Significantly greater decreases in LDL cholesterol during active weight loss are achieved with diets low in saturated fatty acids. Changes in HDL cholesterol between diets appear dependent on both the fat content of the diet and the duration of energy restriction.     

Effects of a lacto-ovo vegetarian diet on serum concentrations of cholesterol, triglyceride, HDL-C, HDL2-C, HDL3-C, apoprotein-B, and Lp(a)

The effect of intervention with a lacto-ovo vegetarian diet on serum concentrations of cholesterol, triglyceride, total high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL3-C, low-density lipoprotein cholesterol, apoprotein-B, apoprotein-HDL, and Lp(a) was studied in 19 men and 17 women. Most weekday meals were obtained from a single source and dietary records were completed to assess the changes in nutrient intakes. Blood was collected in the 6th wk of each dietary period. Because of strong correlations between many of the changes in nutrient intakes, principal component (factor) analysis was used followed by stepwise multiple regression analysis to identify associations between changes in diet and changes in lipid, lipoprotein or apoprotein levels. Three principal components accounted for 92.0% of the variation in lipid levels: factor 1 represented an increase in saturated fat, total fat, monounsaturated fat, cholesterol, and energy intake: factor 2 represented an increase in fiber and polyunsaturated fat, and decrease in protein intake; factor 3 an increase in total carbohydrate, complex carbohydrate, and energy intake. Where a change in a variable was significantly associated with change in diet, one factor appeared primarily responsible for the change; total cholesterol (factor 2, p = 0.034); triglyceride (factor 3, p = 0.005); apo-HDL (factor 1, p = 0.014); HDL2-C (factor 2, p = 0.023), HDL3-C (factor 3, p = 0.015). A borderline significant association was seen for total HDL-C (factor 2, p = 0.055).     

Concordant lipoprotein and weight responses to dietary fat change in identical twins with divergent exercise levels 1

BACKGROUND: Individuals vary greatly in their lipoprotein responses to low-fat diets, with some of this variation being attributable to genes. OBJECTIVE: The purpose was to test the extent to which individual lipoprotein responses to diet can be attributed to genes in the presence of divergent exercise levels. DESIGN: Twenty-eight pairs of male monozygotic twins (one twin mostly sedentary, the other running an average of 50 km/wk more than the sedentary twin) went from a 6-wk 40%-fat diet to a 6-wk 20%-fat diet in a crossover design. The diets reduced fat primarily by reducing saturated and polyunsaturated fat (both from 14% to 4%) while increasing carbohydrate intake from 45% to 65%. RESULTS: Despite the twins' differences in physical activity, the dietary manipulation produced significantly correlated changes (P < 0.05) in the twins' total cholesterol (r = 0.56); LDL cholesterol (r = 0.70); large, buoyant LDL [Svedberg flotation rate (S(f)) 7-12; r = 0.52]; apolipoprotein A-I (r = 0.49); lipoprotein(a) (r = 0.49); electrophoresis measurements of LDL-I (LDLs between 26 and 28.5 nm in diameter; r = 0.48), LDL-IIB (25.2-24.6 nm; r = 0.54), and LDL-IV (22-24.1 nm; r = 0.50); and body weight (r = 0.41). Replacing fats with carbohydrates significantly decreased the size and ultracentrifuge flotation rate of the major LDL and the LDL mass concentrations of large, buoyant LDL; LDL-I; HDL cholesterol; and apolipoprotein A-I and significantly increased concentrations of LDL-IIIA (24.7-25.5 nm) and lipoprotein(a). CONCLUSIONS: Even in the presence of extreme differences in exercise, genes significantly affect changes in LDL, apolipoprotein A-I, lipoprotein(a), and body weight when dietary fats are replaced with carbohydrates.     

Effect of diets high in butter, corn oil, or high-oleic acid sunflower oil on serum lipids and apolipoproteins in men

This randomized blind crossover study compared serum lipid and apolipoprotein concentrations in 20 men consuming 37-43% of energy as fat from diets based on corn oil, high-oleic acid sunflower oil, and butter. Each phase of the crossover design included 2 wk of butter-based diet followed by 5 wk of designated vegetable-oil-based diet with a 7-wk washout period between phases. Compared with values for the butter-based diet, the vegetable-oil-based diets reduced serum total cholesterol by 16-21% (p less than 0.001), LDL cholesterol by 21-26% (p less than 0.001), triglycerides by 10-21% (p less than 0.01 for the higher figure), and apolipoprotein B-100 by 22-29% (p less than 0.001). When values fell, they fell further on the corn-oil-based diet. There were no significant changes in serum HDL cholesterol or apolipoprotein A-1. These data suggest that when men on diets high in saturated fatty acids reduce their saturated fatty acid intake but not their total fat intake, many can still experience a significant lowering in serum total cholesterol.     

Effects of a low-fat vegan diet and a Step II diet on macro- and micronutrient intakes in overweight postmenopausal women

OBJECTIVE: This study investigated the nutrient intake of overweight postmenopausal women assigned to a low-fat vegan diet or a Step II diet. METHODS: Fifty-nine overweight (body mass index, 26 to 44 kg/m2) postmenopausal women were randomly assigned to a self-selected low-fat vegan or a National Cholesterol Education Program Step II diet in a 14-wk controlled trial on weight loss and metabolism. Nutrient intake, which was measured per 1000 kcal, was the main outcome measure. Statistical analyses included within-group and between-group t tests examining changes associated with each diet. RESULTS: Consumption of a low-fat vegan diet was associated with greater decreases in fat, saturated fat, protein, and cholesterol intakes and greater increases in carbohydrate, fiber, beta-carotene, and total vitamin A intakes than was a Step II diet. The low-fat vegan group also increased thiamin, vitamin B6, and magnesium intakes more than the Step II group, and both groups increased folic acid, vitamin C, and potassium intakes. If considering only food sources of micronutrients, the low-fat vegan group decreased vitamin D, vitamin B12, calcium, selenium, phosphorous, and zinc intakes compared with baseline. However, with incidental supplements included, decreases were evident only in phosphorous and selenium intakes. No micronutrient decreases were found in the Step II group. CONCLUSIONS: Individuals on a low-fat vegan or Step II diet should take steps to meet the recommended intakes of vitamin D, vitamin K, folic acid, calcium, magnesium, and zinc. Individuals on a low-fat vegan diet should also ensure adequate intakes of vitamin B12, phosphorous, and selenium.     

北京市区儿童营养状况与血脂谱水平相关性分析

目的 :　了解儿童营养状况与血脂谱水平的相关性。方法 :　对北京市朝阳区 3 1 6名7～ 1 1岁儿童进行血脂谱水平检测、膳食调查及体格检测。结果 :　儿童脂肪供能比为 3 6.2 1 % ,超出标准上限 (2 5 %～ 3 0 % ) ,60 .1 %儿童每日胆固醇摄入量≥ 3 0 0 mg;儿童每日胆固醇摄入量与TC、apo B水平呈正相关 ,糖类供能比与 HDL-C水平正相关 ;高胆固醇摄入组儿童 TC、LDL-C、apoAI水平大于低胆固醇组 ;超重 /肥胖儿童 TC、TG、LDL-C、apo B、Lp(a)水平高于体重正常组及体重不足组 ,并随肥胖程度的增加而增加 ;男童腰臀围比与 TC、TG、LDL-C、apo B水平正相关 ,与HDL-C负相关。结论 :　超重 /肥胖 (尤其向心性肥胖 )、不合理膳食与儿童血脂异常关系密切 ,可以作为早期诊断血脂异常高危儿童的指标     

Weight Loss is Correlated with an Improved Lipoprotein Profile in Obese Postmenopausal Women

Background: Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight.

Objective: The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity.

Design: A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin®, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30–38 kg/m²) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints.

Results: Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption.

Conclusion: Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.     

Fish consumption shifts lipoprotein subfractions to a less atherogenic pattern in humans

The effect of fish consumption on plasma lipoprotein subfraction concentrations was studied in 22 men and women (age > 40 y). Subjects were provided an average American diet (AAD, 35% of energy as fat, 14% as saturated fat, and 35 mg cholesterol/MJ) for 6 wk before being assigned to a National Cholesterol Education Program (NCEP) Step 2 high-fish diet (n = 11, 26% of energy as fat, 4.5% as saturated fat, and 15 mg cholesterol/MJ) or a NCEP Step 2 low-fish diet (n = 11, 26% of energy as fat, 4.0% as saturated fat, and 11 mg cholesterol/MJ) for 24 wk. All food and drink were provided to study participants. Consumption of the high-fish NCEP Step 2 diet was associated with a significant reduction in medium and small VLDL, compared with the AAD diet, whereas the low-fish diet did not affect VLDL subfractions. Both diets significantly reduced LDL cholesterol concentrations, without modifying LDL subfractions. Both diets also lowered HDL cholesterol concentrations. However, the high-fish diet significantly lowered only the HDL fraction containing both apolipoprotein (apo) AI and AII (LpAI:AII) and did not change HDL subfractions assessed by NMR, whereas the low-fish diet significantly lowered the HDL fraction containing only apo AI (LpAI) and the large NMR HDL fractions, resulting in a significant reduction in HDL particle size. Neither diet affected VLDL and LDL particle size. Our data indicate that within the context of a diet restricted in fat and cholesterol, a higher fish content favorably affects VLDL and HDL subspecies.     

The effects of low cholesterol, high polyunsaturated fat, and low fat diets on plasma lipid and lipoprotein cholesterol levels in normal and hypercholesterolemic subjects

The effects of various cholesterol-lowering diets on plasma lipid and lipoprotein cholesterol levels were assessed in normal and hypercholesterolemic subjects. The base-line diet was an ad libitum hospital diet of normal composition. Diet A was a 20% protein, 40% carbohydrate, 40% fat, polyunsaturated:saturated fat ratio 0.1 to 0.3, 250 to 300 mg cholesterol diet, diet B was identical to diet A except that the polyunsaturated/saturated fat ratio was 1.8 to 2.2, and diet C was a 20% protein, 80% carbohydrate, very low fat (5 to 10 g), polyunsaturated/saturated fat ratio 0.1 to 0.3, 150 to 200 mg cholesterol diet. Diet A (low cholesterol) caused mean reductions in plasma, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol of 5.9, 5.6, and 6.3%, respectively, in 11 normal subjects. Diet B (low cholesterol, high polyunsaturated fat) caused significant decreases in plasma cholesterol, LDL cholesterol and HDL cholesterol of 17.0, 16.2, and 17.4%, respectively, in 12 normal subjects; and reductions of 11.0, 10.8, and 17.1%, respectively, in 19 hypercholesterolemic subjects. Diet C (low cholesterol, very low fat) produced significant mean decreases in plasma, LDL, and HDL cholesterol of 26.7, 29.9, and 27.9%, respectively, in 11 normal subjects, and in nine hypercholesterolemic patients of 22.6, 27.2, and 28.6%, respectively. The reductions in plasma cholesterol caused by these diets were therefore due to decreases in both LDL and HDL cholesterol with no significant changes in the LDL cholesterol:HDL cholesterol ratio.     

A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations

BACKGROUND: Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake. OBJECTIVE: We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake. DESIGN: Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin. RESULTS: Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (+/-SE) spontaneous energy intake decreased by 441 +/- 63 kcal/d, body weight decreased by 4.9 +/- 0.5 kg, and fat mass decreased by 3.7 +/- 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC. CONCLUSIONS: An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.     

Reducing total dietary fat without reducing saturated fatty acids does not significantly lower total plasma cholesterol concentrations in normal males.

Forty-eight healthy male students ate an average American diet (AAD) with 37% of calories from fat and 16% from saturated fatty acids for 3 wk. During the next 7 wk, one-third of the students continued to eat the AAD, one-third switched to a 30%-fat diet with 9% saturated fatty acids (Step 1 diet), and one-third switched to a 30%-fat diet with 14% saturated fatty acids (Sat diet). The Step 1 group had a significant reduction in plasma total cholesterol (TC) (0.36 +/- 0.37 mmol/L) compared with the AAD group (0.07 +/- 0.39 mmol/L) and the Sat group (0.08 +/- 0.25 mmol/L). The Sat group did not differ from the AAD group. Changes in low-density-lipoprotein (LDL) cholesterol paralleled changes in total cholesterol. High-density-lipoprotein cholesterol fell significantly in the Step 1 group (0.11 +/- 0.08 mmol/L) compared with the AAD group. Plasma triglycerides did not differ between groups at the end of the randomized periods. In summary, reduction of dietary fat intake from 37% to 30% of calories did not lower plasma total and LDL cholesterol concentrations unless the reduction in total fat was achieved by decreasing saturated fatty acids.     

Low-fat and high-monounsaturated fatty acid diets decrease plasma cholesterol ester transfer protein concentrations in young, healthy, normolipemic men

BACKGROUND: Cholesterol ester transfer protein (CETP) mediates the transfer of cholesteryl esters from HDL to apolipoprotein (apo) B-containing lipoproteins. The possible atherogenic role of this protein is controversial. Diet may influence plasma CETP concentrations. OBJECTIVE: The objective was to determine whether the changes in plasma lipids observed after consumption of 2 lipid-lowering diets are associated with changes in plasma CETP concentrations. DESIGN:: We studied 41 healthy, normolipidemic men over 3 consecutive 4-wk dietary periods: a saturated fatty acid-rich diet (SFA diet: 38% fat, 20% saturated fat), a National Cholesterol Education Program Step I diet (NCEP Step I diet: 28% fat, 10% saturated fat), and a monounsaturated fatty acid-rich diet (MUFA diet: 38% fat, 22% monounsaturated fat). Cholesterol content (27.5 mg/MJ) was kept constant during the 3 periods. Plasma concentrations of total, LDL, and HDL cholesterol; triacylglycerol; apo A-I and B; and CETP were measured at the end of each dietary period. RESULTS: Compared with the SFA diet, both lipid-lowering diets significantly decreased plasma total and LDL cholesterol, apo B, and CETP. Only the NCEP Step I diet lowered plasma HDL cholesterol. Positive, significant correlations were found between plasma CETP and total (r = 0.3868, P < 0.0001) and LDL (r = 0.4454, P < 0.0001) cholesterol and also between changes in CETP concentrations and those of total (r = 0.4543, P < 0.0001) and LDL (r = 0.4554, P < 0.0001) cholesterol. CONCLUSIONS: The isoenergetic substitution of a high-saturated fatty acid diet with an NCEP Step I or a high-monounsaturated fatty acid diet decreases plasma CETP concentrations.     

Men and women differ in lipoprotein response to dietary saturated fat and cholesterol restriction

A diet restricted in saturated fat and cholesterol is recommended for subjects with elevated LDL cholesterol concentrations before and during drug therapy. Gender differences in lipoprotein subspecies response to such diets have not been studied in detail. We examined the effects of a diet low in total fat, saturated fat and cholesterol (Therapeutic Lifestyle Changes, TLC, diet: 26% of energy as fat, 4% as saturated fat, and 45 mg cholesterol/4.2 MJ), compared with an average American diet (AAD: 35% of energy as fat, 14% as saturated fat, and 147 mg cholesterol/4.2 MJ), on plasma lipoprotein subspecies in men and women. Each diet period lasted 6 wk. Body weight was kept constant during each diet period. Men (n = 19) and postmenopausal women (n = 14) >40 y old with moderate hypercholesterolemia participated in this study. Plasma lipoprotein concentrations were assessed by standardized methodology, and lipoprotein sizes were determined by gradient gel electrophoresis and NMR spectroscopy. The TLC diet resulted in greater reductions in total cholesterol and plasma apolipoprotein B concentrations in men than in women (-19% vs. -12%, P < 0.05, and -18% vs. -9%, P < 0.05, respectively). Postprandial triacylglycerol and LpAI:AII concentrations were reduced in men, but not in women (-15% vs. 8%, P < 0.05, and -9% vs. -2%, respectively, P < 0.05). Similar decreases in LpAI concentrations and LDL and HDL particle size were observed in men and women. These data are consistent with the concept that middle aged/elderly men may have a more favorable lipoprotein response to a low fat, low cholesterol diet than postmenopausal women.     

An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations,the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight,normolipidemic women

Very low carbohydrate diets are popular, yet little is known about their effects on blood lipids and other cardiovascular disease risk factors. We reported previously that a very low carbohydrate diet favorably affected fasting and postprandial triacylglycerols, LDL subclasses and HDL cholesterol (HDL-C) in men but the effects in women are unclear. We compared the effects of a very low carbohydrate and a low fat diet on fasting lipids, postprandial lipemia and markers of inflammation in women. We conducted a balanced, randomized, two-period, crossover study in 10 healthy normolipidemic women who consumed both a low fat (<30% fat) and a very low carbohydrate (<10% carbohydrate) diet for 4 wk each. Two blood draws were performed on separate days at 0, 2 and 4 wk and an oral fat tolerance test was performed at baseline and after each diet period. Compared with the low fat diet, the very low carbohydrate diet increased (P 相似文献