Association of sex, adiposity, and diet with HDL subclasses in middle-aged Chinese.

BACKGROUND: There is limited information regarding the associations of lifestyle factors and sex with HDL subclasses containing apolipoprotein (apo) A-I (Lp A-I) and both apo A-I and apo A-II (Lp A-I:A-II). OBJECTIVE: We sought to examine the relations between 2 major HDL subclasses and sex, menopausal status, nutrient intakes, and adiposity. DESIGN: We conducted interviews and measured blood variables in 409 government employees aged 40-59 y in Taiwan. RESULTS: Women (n = 203) had significantly higher concentrations of HDL cholesterol, Lp A-I, and Lp A-I:A-II than did men (n = 206). Postmenopausal women (n = 72) had higher concentrations of HDL cholesterol, Lp A-I, and Lp A-I:A-II than did premenopausal women (n = 131). Body mass index and waist-to-hip ratio were strong predictors of and exerted an independent additive effect on Lp A-I concentrations in both men and women. However, body adiposity was associated with Lp A-I:A-II concentrations only in men. Waist-to-hip ratio was an independent determinant of Lp A-I but not of Lp A-I:A-II in men and postmenopausal women after adjustment for age, body mass index, smoking, and diet. Although there were relatively weak associations between dietary factors and both HDL subclasses (r = 0.01-0.26) in men and women according to bivariate analyses, multiple regression models showed that total fat, saturated fat, and cholesterol intakes were significantly correlated with HDL cholesterol and both Lp A-I and Lp A-I:A-II in men, but not in women. CONCLUSION: Our data suggest that body adiposity and dietary fat consumption affect 2 major HDL subclasses differently depending on subject sex and menopausal status.     

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.     

Dietary mono- and polyunsaturated fatty acids similarly increase plasma apolipoprotein A-IV concentrations in healthy men and women

We investigated the effect of dietary fatty acid composition on plasma apolipoprotein (apo) A-IV concentrations. Plasma apo A-IV concentrations were measured by ELISA in plasma of 48 healthy men and women in a controlled dietary study. First, all participants consumed a 2-wk baseline diet rich in saturated fatty acids (SFA). Then, they were randomly assigned to one of three dietary treatments, which contained refined olive oil [rich in monounsaturated fatty acids (MUFA), n = 17], rapeseed oil [rich in MUFA and alpha-linolenic acid [18:3(n-3)], n = 13], or sunflower oil [rich in (n-6) PUFA, n = 18] as the principal source of fat for 4 wk. The plasma concentrations of apo A-IV increased when subjects consumed the diets rich in unsaturated fatty acids, by 16% or 13.0 mg/L [F((2,76)) = 12.874, P < 0.001 by repeated-measures ANOVA]. The increase was not affected by diet group affiliation, gender or apo A-IV genotype. In conclusion, diets rich in unsaturated fatty acids, independent of the degree of unsaturation, gender and apo A-IV genotype, increase plasma apo A-IV concentrations compared with a baseline diet rich in SFA in healthy men and women.     

Effect of dietary monounsaturated fatty acids on plasma lipoproteins and apolipoproteins in women.

To determine the effects of dietary fat saturation on plasma lipoproteins, we studied 21 free-living normolipidemic women (13 pre- and 8 postmenopausal) on three consecutive diet periods. During the first 4 wk they consumed a saturated diet rich in palm oil and butter [19% saturated fatty acids (S), 14% monounsaturated fatty acids (M), and 3.5% polyunsaturated fatty acids (P)], followed by 6 wk of a monounsaturated diet rich in olive oil (11% S, 22% M, and 3.6% P), and 6 wk of a polyunsaturated diet rich in sunflower oil (10.7% S, 12.5% M, and 12.8% P). Compared with the diet rich in saturated fatty acids, both diets rich in unsaturated fatty acids had similar lowering effects on total and low-density-lipoprotein cholesterol. High-density lipoprotein cholesterol and apolipoprotein A-I were higher in the monounsaturated-rich period than in the polyunsaturated-rich (10.5% and 12.7% respectively, P less than 0.001) and the saturated-rich period (5.3%, and 7.9%, respectively, P less than 0.05). These effects were independent of menopause status. Our data show that at this level of fat intake (36% as calories), a monounsaturated-rich diet results in a less atherogenic lipid profile than either polyunsaturated- or saturated-rich diets.     

Increased plasma concentrations of lipoprotein(a) during a low-fat, high-carbohydrate diet are associated with increased plasma concentrations of apolipoprotein C-III bound to apolipoprotein B-containing lipoproteins

BACKGROUND: Low-fat, high-carbohydrate (LFHC) diets have been shown to increase plasma concentrations of lipoprotein(a) [Lp(a)] and of triacylglycerol- rich lipoproteins (TRLs). OBJECTIVE: We tested whether increases in plasma Lp(a) induced by an LFHC diet are related to changes in TRLs. DESIGN: Healthy men (study 1; n = 140) consumed for 4 wk each a high-fat, low-carbohydrate diet (HFLC; 40% fat, 45% carbohydrate) and an LFHC diet (20% fat, 65% carbohydrate). Plasma lipids; lipoproteins; apolipoprotein (apo) B, A-I, and C-III; and Lp(a) were measured at the end of each diet. In a second group of men following a similar dietary protocol (study 2; n = 33), we isolated apo(a)-containing particles by immunoaffinity chromatography and determined the concentrations of apo C-III in ultracentrifugally isolated subfractions of apo B-containing lipoproteins. RESULTS: In study 1, plasma concentrations of Lp(a) (P < 0.001), triacylglycerol (P < 0.001), apo B (P < 0.005), apo C-III (P < 0.005), and apo C-III in apo B-containing lipoproteins (non-HDL apo C-III) (P < 0.001) were significantly higher with the LFHC diet than with the HFLC diet. Stepwise multiple linear regression analysis showed that the association of changes in Lp(a) with changes in non-HDL apo C-III was independent of changes in body mass index, apo B, LDL cholesterol, and HDL cholesterol. Plasma lipid and lipoprotein changes were similar in study 2, and we found that both total apo C-III and the apo C-III content of apo(a)-containing particles were increased in a TRL fraction consisting predominantly of large VLDL particles [TRL-apo(a)]. CONCLUSIONS: The increase in plasma Lp(a) with an LFHC diet is significantly associated with an increase in non-HDL apo C-III. Enrichment of TRL-apo(a) with apo C-III may contribute to this dietary effect on Lp(a) concentrations.     

Olive oil, corn oil, and n-3 fatty acids differently affect lipids, lipoproteins, platelets, and superoxide formation in type II hypercholesterolemia.

To evaluate which dietary fat may provide the best response in terms of plasma lipids and lipoproteins and also of platelet aggregability and superoxide formation by white blood cells, 12 type II patients were randomly allocated to three different diets, which provided polyunsaturated fatty acids (corn oil), monounsaturated fatty acids (olive oil), and a supplementation of ethyl esters of n-3 fatty acids to a prudent diet. Olive oil and, more significantly, n-3 ethyl esters lowered total cholesterol best (-2.2% and -5.8%, respectively); the latter diet, as expected, also significantly lowered triglyceridemia (-21.4%). The corn-oil diet exerted a small, statistically significant reduction of high-density-lipoprotein cholesterol (HDL) (-4.3%), and it also lowered plasma total apo B concentrations (-3.8%). n-3 ethyl esters significantly raised both total (+3.1%) and particularly HDL2 cholesterol (+24%). Platelet reactivity was insignificantly reduced by the three regimens, but all three significantly reduced thrombin-stimulated formation of thromboxane B2. Finally, only the n-3 fatty acid supplementation significantly reduced O2- generation by adherent monocytes. Dietary unsaturated fatty acids are generally effective on the plasma lipid and lipoproteins in type II patients, but significant differences may be found between the three tested regimens.     

Lipoprotein-containing apolipoprotein A-I: sex-related quantitative and qualitative changes in this lipoprotein subspecies after ingestion of fat.

We investigated the postprandial changes of two species of lipoproteins containing apolipoprotein (apo)A-I: lipoprotein containing apo A-I but no apo A-II (LpA-I), and lipoprotein containing apo A-I and apo A-II (LpA-I/A-II). These lipoproteins were isolated from 10 men and 11 women at 0, 4, and 6 h after they had eaten butter. In LpA-I, the concentrations of all lipids except triglyceride were increased at 4 and 6 h in the women. In the men all lipids were increased only at 4 h. The increase of apo A-I concentration was found at 6 h only in the women. In LpA-I/A-II, the concentrations of all lipids were increased at 4 h and only phospholipid (PL) was increased at 6 h in the women. In the men, free cholesterol and PL were increased at 4 and 6 h. The increases of apo A-I and apo A-II concentrations were found at 4 and 6 h only in the men. These results suggest that the postprandial changes are sex-related and may relate to the different incidence of atherosclerotic cardiovascular disorders.     

Balance of unsaturated fatty acids is important to a cholesterol-lowering diet: comparison of mid-oleic sunflower oil and olive oil on cardiovascular disease risk factors

OBJECTIVE: To evaluate the effects of a trans fat-free monounsaturated fatty acid-rich vegetable oil (NuSun sunflower oil, National Sunflower Association, Bismark, ND) that is a good source of polyunsaturated fatty acids (PUFA) and low in saturated fatty acids on lipid and lipoprotein levels and oxidative stress. DESIGN: A double-blinded, randomized, three period crossover, controlled feeding study. SUBJECTS/SETTING: Thirty-one men (n=12) and women (n=19) with moderate hypercholesterolemia who were 25 to 64 years of age. INTERVENTION: Experimental diets provided 30% fat (olive oil or NuSun sunflower oil contributed one half of the total fat), 8.3% vs 7.9% saturated fatty acid, 17.2% vs 14.2% monounsaturated fatty acid, and 4.3% vs. 7.7% PUFA (olive oil and NuSun sunflower oil, respectively), and 294 mg cholesterol. The control diet was an average American diet (34% fat, 11.2% saturated fatty acid, 14.9% monounsaturated fatty acid, 7.8% PUFA). Subjects consumed each diet for 4 weeks with a 2-week compliance break before crossing over to another diet. MAIN OUTCOME MEASURES: Lipid and lipoprotein levels were measured, and measures of oxidative stress, including lag time, rate of oxidation, total dienes, and lipid hydroperoxides, were assessed. STATISTICAL ANALYSIS: The mixed model procedure was used to test for main effects of diet, feeding period, and order of diets. Tukey-Kramer adjusted P values were used to determine diet effects. RESULTS: The NuSun sunflower oil diet decreased both total and low-density lipoprotein cholesterol levels compared with the average American diet and the olive oil diet. There was no effect of the olive oil diet compared with the average American diet. Total cholesterol decreased 4.7% and low-density lipoprotein cholesterol decreased 5.8% on the NuSun sunflower oil diet vs the average American diet. There was no effect of the experimental diets on triglyceride levels, rate of oxidation, total dienes, lipid hydroperoxides, or alpha-tocopherol. Lag time was the longest following the olive oil diet and shortest following the NuSun sunflower oil diet. CONCLUSIONS: The higher PUFA content appeared to account for the greater total and low-density lipoprotein cholesterol lowering and reduction in lag time of the NuSun sunflower oil diet. However, the fact that there were no differences in the resulting oxidation products suggests there were no adverse effects on low-density lipoprotein oxidation. Since PUFAs are important for cholesterol lowering, foods that replace saturated fatty acids should include a balance of unsaturated fatty acids.     

Dietary exchange of an olive oil and sunflower oil blend for extra virgin olive oil decreases the estimate cardiovascular risk and LDL and apolipoprotein AII concentrations in postmenopausal women

BACKGROUND: Dietary supplementation with Virgin olive oil is considered cardioprotective. Decreasing LDL and apolipoprotein (apo) AII-lipoproteins is also appropriate for CHD protection and treatment. AIM: To study the effects of an 8%En dietary exchange of linoleic acid for oleic acid on serum and lipoprotein levels and serum and LDL-TBARS in postmenopausal women consuming a diet rich in fat (46%En; saturated/monounsaturated/polyunsaturated profile: 1.1/1.9/1). EXPERIMENTAL DESIGN: 14 postmenopausal women (63 +/- 11 years) were assigned to exchange during 28-day dietary period the culinary oil used for years consisting in a blend of olive oil plus sunflower oil (SO) for extra virgin olive oil (EVOO). SO and EVOO represented 62% of the total lipid intake. DETERMINATIONS: Dietary intakes, serum Lp(a), and cholesterol, triglycerides, phospholipids, protein, apolipoproteins AI, AII, B were determined in serum and lipoproteins. RESULTS: The dietary intervention decreased serum total cholesterol (TC), phospholipids, apo AII (all, p < 0.001) and apo B (p < 0.01). Except for triglycerides, all components of the LDL fraction decreased (at least, p < 0.05). HDL-cholesterol was not affected but HDL-phospholipids and HDL-lipids decreased (at least, p < 0.01). VLDL-apo B and VLDL-proteins decreased (all, p < 0.001). Serum Lp(a), TBARS and LDL-TBARS were not affected by the dietary exchange. The estimate of 10-year cardiovascular risk decreased (p < 0.05). Apo AII (p = 0.061) and LDL-cholesterol (p < 0.05) underwent greater modifications in normocholesterolemics, while LDL-phospholipids (p = 0.094), experienced greater alterations in hypercholesterolemics. No significant interaction was observed between dietary exchange and age (> or <65 yrs). CONCLUSIONS: These findings suggest that the dietary exchange of an olive oil and sunflower oil blend for extra virgin olive decreases LDL and apo AII levels, and the estimate of 10-year cardiovascular risk.     

The effect of a high cholesterol and saturated fat diet on serum high-density lipoprotein-cholesterol, apoprotein A-I, and apoprotein E levels in normolipidemic humans

The effects of a high cholesterol, high saturated fat diet on serum high density lipoprotein cholesterol, apo A-I, and apo E levels were studied in six normolipidemic subjects. The study was done on an outpatient basis and mixed natural foods normally consumed by humans were used. When compared with a low cholesterol (98 mg/day) high polyunsaturated fat (P/S ratio 1.6) diet, the high cholesterol (1021 mg/day), high saturated fat (P/S ratio 0.4) diet increased serum cholesterol (23%) by raising the cholesterol concentration in very low-density lipoproteins (59%), low-density lipoproteins (15%), and high-density lipoproteins (30%). The low-density lipoprotein-cholesterol/high-density lipoprotein-cholesterol ratio fell significantly from 1.78 to 1.58. The increased high-density lipoprotein-cholesterol was associated with an elevation of serum apo A-I but not apo E. Serum triglycerides did not change significantly.     

The effect of replacing dietary saturated fat with polyunsaturated or monounsaturated fat on plasma lipids in free-living young adults

OBJECTIVE: To examine, in free-living adults eating self-selected diets, the effects on plasma cholesterol of substituting saturated fat rich foods with either n-6 polyunsaturated or monounsaturated fat rich foods while at the same time adhering to a total fat intake of 30-33% of dietary energy. DESIGN: Two randomised crossover trials. SETTING: General community. SUBJECTS: Volunteer sample of healthy free-living nutrition students at the University of Otago. Trial I, n=29; and trial II, n=42. INTERVENTIONS: In trials I and II participants were asked to follow for 2(1/2) weeks a diet high in saturated fat yet with a total fat content that conformed to nutrition recommendations (30-33% energy). During the 2(1/2) week comparison diet, saturated fat rich foods were replaced with foods rich in n-6 polyunsaturated fats (trial I) whereas in trial II the replacement foods were rich in monounsaturated fats. Participants were asked to maintain a total fat intake of 30-33% of energy on all diets. MAIN OUTCOME MEASURES: Energy and nutrient intakes, plasma triglyceride fatty acids, and plasma cholesterol. RESULTS: When replacing saturated fat with either n-6 polyunsaturated fat or monounsaturated fat, total fat intakes decreased by 2.9% energy and 5.1% energy, respectively. Replacing saturated fat with n-6 polyunsaturated fat (trial I) lowered plasma total cholesterol by 19% [from 4.87 (0.88) to 3.94 (0.92) mmol/l, mean (s.d.)], low density lipoprotein cholesterol by 22% [from 2.87 (0.75) to 2.24 (0.67) mmol/l], and high density lipoprotein cholesterol by 14% [from 1.39 (0.36) to 1.19 (0.34) mmol/l], whereas replacing saturated fat with monounsaturated fat (trial II) decreased total cholesterol by 12%, low density lipoprotein cholesterol by 15%, and high density lipoprotein cholesterol by 4%, respectively. The change in the ratio of total to high density lipoprotein cholesterol was similar during trial I and trial II. CONCLUSIONS: Young adults are very responsive to dietary-induced changes in plasma cholesterol even when an isocaloric replacement of saturated fat with n-6 polyunsaturated or monounsaturated fat is not achieved. Replacing saturated fat with either n-6 polyunsaturated or monounsaturated fat is equally efficacious at reducing the total to high density lipoprotein cholesterol ratio. SPONSORSHIP: University of Otago, Meadow Lea Ltd.     

Interrelationship of plasma triglycerides and HDL size and composition in rats fed different dietary saturated fats

We investigated the relative effects of different dietary saturated fats on the size distribution, apolipoprotein (apo) and chemical composition of HDL in fasted rats. Male Sprague-Dawley rats (174 +/- 2 g) were fed diets containing 0.035% cholesterol and 16% fat (wt/wt) from corn oil (CO diet) or from 2% CO plus 14% butterfat (BF diet), beef tallow (BT diet), palm oil (PO diet) or coconut oil (CN diet) for 6 wk. Apparent lipid digestibility was significantly lower with the PO and BT diets vs. the CO, BF and CN diets. Plasma total cholesterol levels were significantly higher in rats fed the PO and BT diets than in rats fed the BF and CN diets but were not different among the PO-, BT- and CO-fed groups. Nondenaturing gradient gel electrophoresis immunoblot analysis indicated that HDL apo A-I and E resided on particles with significantly smaller modal diameters in rats fed all saturated fats compared with those fed the CO diet. Chemical analyses indicated that HDL generally contained proportionately less protein and more triglyceride, free cholesterol and apo E with saturated fat feeding than with CO diet feeding. Significantly higher plasma and VLDL triglyceride levels were noted with ingestion of the BT, PO or CN diet than with the CO diet. Butterfat feeding resulted in lower plasma triglycerides and HDL-esterified cholesterol than did feeding the other saturated fats. Very low density lipoprotein triglyceride concentrations were inversely correlated with HDL modal diameter of apo E containing lipoproteins (P less than 0.005). These data provide further evidence of the interrelationship of triglyceride and HDL metabolism and suggest that mechanisms independent of cholesterol ester transfer protein may mediate this response in rats.     

Olive-oil-enriched diet: effect on serum lipoprotein levels and biliary cholesterol saturation

The effect of diet enriched with a monounsaturated fatty acid (olive oil) on serum lipoproteins, biliary cholesterol saturation index, and gallbladder motility compared with a standard low-fat diet was evaluated in 11 young volunteers admitted to a metabolic ward. A significant decrease of mean total cholesterol (-9.5%), total apo B (-7.4%), LDL cholesterol (-12.2%), and total triglycerides (-25.5%) was observed after the olive-oil-enriched diet. Total HDL- and HDL-subfractions-cholesterol levels as well as serum apo A-I mean levels remained unchanged. Cholesterol saturation index of the bile and fasting and after-meal gallbladder volumes were unaffected by the enriched diet as compared with the low-fat diet. Olive oil may be a natural fat that can be used for the control of plasma and LDL cholesterol as a valid alternative to polyunsaturated fatty acids.     

Effects of saturated, monounsaturated, and omega-6 polyunsaturated fatty acids on plasma lipids, lipoproteins, and apoproteins in humans

The effects of dietary fats on plasma cholesterol, serum lipoproteins, and apoproteins (Apo), A-1, B, and CIII were studied. Twelve men consumed three different cholesterol-free formula diets in which polyunsaturated and saturated fats were partially substituted (20% of calories) for monoenoic fats with a constant of 40% of calories from fat. Total cholesterol and low-density lipoprotein cholesterol dropped from base-line values of 166 and 103 to 133 and 81 mg/dl (sat), 127 and 71 mg/dl (mono), and 123 and 65 mg/dl (poly), respectively. High-density lipoprotein cholesterol changed very little from base-line values of 46 to 40 mg/dl (sat), 45 mg/dl (poly), and 43 mg/dl (mono). The plasma concentrations of ApoB declined from base-line values of 80.3 mg/dl to 54.6 mg (mono), 51.8 mg (poly), and 59.6 mg (sat) while Apo CIII and Apo AI did not show any changes. This study demonstrates that: 1) changes in dietary fat affect serum lipids, lipoproteins, and apoproteins even when consumed on a cholesterol-free diet, and 2) omega-6 polyunsaturated fat lowers low-density lipoprotein cholesterol, total cholesterol, and ApoB to a greater extent than monounsaturated or saturated fat, 3) consumption of a cholesterol-free formula diet results in significant decreases in the concentrations of total and low-density lipoprotein cholesterol in plasma when compared to values obtained on a mixed food home diet containing approximately 300 mg cholesterol/day.     

Lowering of HDL2-cholesterol and lipoprotein A-I particle levels by increasing the ratio of polyunsaturated to saturated fatty acids

The protective role of high-density lipoproteins (HDLs) has been attributed to the subfractions HDL2 (according to the density) and lipoprotein A-I (LpA-I) (according to the composition in apolipoproteins). We investigated the effect of a high ratio of polyunsaturated to saturated fatty acids (P:S) on these subfractions in a homogeneous group of young adult males. Two prescribed diets were consumed successively at the subjects' homes for 3 wk each in a random order; one diet contained 70 g butter (P:S 0.2, diet B), the other contained 70 g sunflower margarine (P:S 1.1, diet M). Total calorie, fat, and cholesterol intakes were similar for the two diets. Cholesterol and apolipoprotein B in serum and in low-density lipoproteins (LDLs) were lower with diet M than with diet B. However, significant decreases in protective subfractions of HDL, HDL2, and LpA-I were observed. This undesirable effect of the diet with a high P:S could cancel the benefits of lowering the LDL-cholesterol concentrations.     

Effects of long-term monounsaturated- vs polyunsaturated-enriched diets on lipoproteins in healthy men and women.

The effect of dietary-fat saturation on plasma lipoprotein concentrations was assessed in 46 men and 32 women placed on a diet enriched in polyunsaturated fatty acids (sunflower oil) for 12 wk and, under isocaloric conditions, on a diet enriched in monounsaturated fatty acids (olive oil) for the next 16 wk in men and 28 wk in women. Fat comprised 37% of the total energy intake in men and 36% in women. At the end of the monounsaturated fatty acid diet no change occurred in total cholesterol (TC) in men but it increased by 9% in women. High-density-lipoprotein (HDL) cholesterol increased by 17% in men and by 30% in women. The atherogenic index (TC:HDL cholesterol) fell significantly in both sexes. No significant changes occurred in plasma low-density-lipoprotein cholesterol or in total triglycerides values. These data show that when compared with polyunsaturates, monounsaturates increased HDL cholesterol and reduced the atherogenic risk profile in both sexes.     

Changes in plasma lipoproteins during low-fat, high-carbohydrate diets: effects of energy intake

BACKGROUND: Low-fat diets can increase plasma triacylglycerol and reduce HDL cholesterol. Changes in energy intake and body weight can influence the lipoprotein response. OBJECTIVE: We sought to prospectively examine the effects of euenergetic and ad libitum dietary fat restriction on plasma lipoproteins in healthy postmenopausal women. DESIGN: Participants first received a controlled euenergetic diet in which dietary fat was reduced stepwise from 35% to 25% to 15% over 4 mo. Thereafter, participants followed an ad libitum 15%-fat diet for 8 mo; 54 women completed the intervention. RESULTS: During the controlled euenergetic diet, plasma triacylglycerol increased from 1.70 +/- 0.10 to 2.30 +/- 0.16 mmol/L, total cholesterol decreased from 5.87 +/- 0.13 to 5.53 +/- 0. 13 mmol/L, LDL cholesterol decreased from 3.41 +/- 0.10 to 2.87 +/- 0.10 mmol/L, HDL cholesterol decreased from 1.76 +/- 0.08 to 1.50 +/- 0.08 mmol/L, and apolipoprotein (apo) A-I decreased from 5.11 +/- 0.14 to 4.78 +/- 0.14 mmol/L (P < 0.0001 for all changes). Hormone replacement therapy did not affect the relative change in HDL cholesterol. Plasma glucose, insulin, hemoglobin A(1C,) free fatty acid, and apo B concentrations did not change significantly. During the ad libitum 15%-fat diet, participants lost 4.6 +/- 0.4 kg. Plasma triacylglycerol and LDL cholesterol returned to baseline values (1.77 +/- 0.12 and 3.31 +/- 0.08 mmol/L, respectively), whereas HDL cholesterol and apo A-I remained low (1.40 +/- 0.08 and 4.82 +/- 0.18 mmol/L, respectively). HDL cholesterol and apo A-I concentrations stabilized in subjects who were not receiving hormone replacement therapy but continued to decline in women who were receiving hormone therapy. CONCLUSIONS: The ad libitum 15%-fat diet resulted in significant weight loss. The euenergetic but not the ad libitum diet caused hypertriacylglycerolemia. HDL cholesterol decreased during both low-fat diets.     

Effects of low fat diets differing in degree of fat unsaturation on plasma lipids, lipoproteins, and apolipoproteins in adult men

The effects of two low fat diets with differing ratios of polyunsaturated to saturated fatty acids (P/S) on blood lipids, lipoproteins (LP), and apolipoproteins (Apo) were studied in 23 adult men, 30-60 years old, using a crossover design. Both test diets had 25% fat calories with either a P/S of 0.3 (Diet 1) or a P/S of 1.0 (Diet 2) and equivalent amounts of cholesterol. The study consisted of four periods: a 5-week prestudy on self-selected diet (SS), two 6-week test diet periods followed by a second 5-week post-study period on the SS diet. When compared with the SS diet, Diet 2 lowered the mean plasma total cholesterol (TC) by about 20% (P less than 0.01). Low density lipoprotein (LDL) cholesterol was also decreased by about 18% by Diet 2 (P less than 0.01). The high P/S diet did not cause a change in total cholesterol in the high density lipoprotein (HDL) subclass2 (HDL2) when compared to the SS diet. Levels of triglycerides (TG) were slightly reduced in HDL2 but showed a greater reduction in HDL3 in both diets. Phospholipids (PL) were significantly reduced in HDL2 and in HDL3, but the reduction in HDL3 PL was not statistically significant. Apo A-I levels were not changed by either diet when compared with the SS diet, but Apo A-II levels of HDL2 and HDL3 were significantly decreased by the low fat diets, and there was no P/S effect. No other consistent changes in apoprotein levels occurred. Our data suggest that, in men with normal lipid levels, practical dietary changes involving a moderate increase in P/S from 0.3 to 1.0 in a low fat, low cholesterol diet do influence lipoprotein composition and apoprotein distribution in a short time. The reduction in cholesterol in total lipid composition and in LDL lipids which accompanied the reduction of dietary fat and cholesterol are considered to be beneficial.     

Macrophage cholesterol efflux elicited by human total plasma and by HDL subfractions is not affected by different types of dietary fatty acids

BACKGROUND: Plasma HDL concentrations and composition, important predictors of coronary heart disease, are modified by fatty acids (FAs) in high-fat diets. OBJECTIVE: Following the National Cholesterol Education Program Adult Treatment Panel III recommendation that 25%-30% of total calorie intake be in the form of fat, we compared the results of the intake of 30% of energy as fat in diets enriched with trans, polyunsaturated, or saturated FAs. These dietary effects on the composition and ability of HDL(2), HDL(3), and total plasma to efflux cholesterol from mouse peritoneal macrophages that previously were loaded with LDL-acetylated 14C-cholesteryl ester were evaluated by using ultracentrifugally isolated lipoproteins. DESIGN: After a 2-wk run-in period, 30 healthy persons (9 M, 21 F), were randomly distributed among 3 groups (n = 10/group) and fed for 4 wk with either an 8.3% trans FA, a 14.6% polyunsaturated FA, or a 13.2% saturated FA diet. The 3 diets had similar proportions of monounsaturated FAs. RESULTS: The percentage of radioactive cell cholesterol removal did not vary among these diets, possibly because of the small difference in the composition of the HDL fraction elicited by the different diets. However, the percentage was consistently higher for HDL(3) than for HDL(2). CONCLUSION: Differences in the cell cholesterol efflux with these diets were not observed, probably because the changes in the HDL composition were quite modest as a result of the limitation of the fat intake to 30% of total calories and because of the rigorous control of the proportions of FAs in the experimental diets used in this investigation.     

Olive oil containing olive oil fatty acid esters of plant sterols and dietary diacylglycerol reduces low-density lipoprotein cholesterol and decreases the tendency for peroxidation in hypercholesterolaemic subjects

Plant sterols (PS) and MUFA are well-documented cholesterol lowering agents. We aimed to determine the effect of PS esterified to olive oil fatty acids (PS-OO) on blood lipid profile and lipid peroxidation in hypercholesterolaemic subjects. Twenty-one moderately overweight, hypercholesterolaemic subjects consumed three consecutive treatment diets, each lasting 28 d and separated by 4-week washout periods, using a randomized crossover design. Diets contained 30 % energy as fat, 70 % of which was provided by olive oil (OO), and differed only in the treatment oils: OO, PS esterified to sunflower oil fatty acids (PS-SO), and PS-OO. Both PS-SO and PS-OO treatments provided 1.7 g PS /d. PS-OO and PS-SO consumption resulted in a decrease (P = 0.0483) in LDL-cholesterol (LDL-C) concentrations compared with the OO diet. Although total cholesterol and apo B-100 levels were not significantly affected, PS-SO and, to some extent, PS-OO reduced the total:HDL-cholesterol (HDL-C) ratio (P = 0.0142) and the apo B-100:apo A-I ratio (P = 0.0168) compared with the OO diet. There were no differences across diets in lipoprotein(a) (Lp(a)) and lipid peroxidation levels. However, following consumption of OO and PS-SO, Lp(a) concentrations increased (P = 0.0050 and 0.0421, respectively), while PS-OO treatment did not affect Lp(a) levels. Furthermore, there was a decrease (P = 0.0097) in lipid peroxidation levels with PS-OO treatment during the supplementation phase. Our results suggest that supplementing an OO-rich diet with PS-OO favourably alters the plasma lipid profile and may decrease the susceptibility of LDL-C to lipid peroxidation in hypercholesterolaemic subjects.