Supplementation with calcium + vitamin D enhances the beneficial effect of weight loss on plasma lipid and lipoprotein concentrations

BACKGROUND: Adequate calcium intake can have a favorable effect on some metabolic variables. OBJECTIVE: The objective of the study was to determine the effects of daily calcium intake and of supplementation with calcium and vitamin D (calcium+D) during a weight-loss intervention on blood pressures, plasma lipid and lipoprotein concentrations, and glucose and insulin concentrations in low calcium consumers. DESIGN: Healthy, overweight or obese women (n = 63) with a daily calcium intake of < 800 mg/d were randomly assigned in a double-blind manner to 1 of 2 groups: the group consuming 2 tablets/d of a calcium + vitamin D supplement (600 mg elemental calcium and 200 IU vitamin D/tablet) or the group consuming placebo; both groups observed a 700 kcal/d energy restriction. These 63 women then completed a 15-wk weight-loss intervention. RESULTS: Initial daily calcium intake was significantly correlated with plasma HDL cholesterol (r = 0.41, P < 0.001) and with 2-h postload glycemia (r = -0.29, P < 0.05) during an oral-glucose-tolerance test, independent of fat mass and waist circumference. After the 15-wk intervention, significantly greater decreases in total:LDL and LDL:HDL (P < 0.01 for both) and of LDL cholesterol (P < 0.05) were observed in the calcium+D group than in the placebo group. The differences in total:HDL and LDL:HDL were independent of changes in fat mass and in waist circumference. A tendency for more beneficial changes in HDL cholesterol, triacylglycerol, and total cholesterol was also observed in the calcium+D group (P = 0.08). CONCLUSION: Consumption of calcium+D during a weight-loss intervention enhanced the beneficial effect of body weight loss on the lipid and lipoprotein profile in overweight or obese women with usual low daily calcium intake.     

Plasma triacylglycerol and HDL cholesterol concentrations confirm self-reported changes in carbohydrate and fat intakes in women in a diet intervention trial

Diet intervention trials are currently testing whether reduced fat intake can reduce the risk and progression of breast cancer. Energy from dietary fat is generally replaced by energy from carbohydrate in these studies, and altering the proportion of energy from dietary carbohydrate and fat has been shown to affect plasma lipid concentrations in controlled feeding studies. The purpose of this study was to examine the effect of increased carbohydrate and reduced fat intakes on plasma lipids in a randomized, controlled trial that is testing the effect of diet modification on risk for recurrence and survival in women previously treated for breast cancer. Plasma concentrations of lipids and related factors were measured at enrollment and 1-y follow-up in 393 women enrolled in the trial. Dietary goals for the intervention group focused on an increase in vegetable, fruit and fiber intakes, and reduced fat intake. Women assigned to the intervention group significantly reduced fat intake (from 28.1 to 21.0% of energy), and significantly increased intakes of carbohydrate (from 56.9 to 65.3% of energy) and fiber (from 21.0 to 29.6 g/d) (P < 0.05). Body weight did not change significantly in either study group. A small but significant increase in fasting plasma triacylglycerol concentration, and decreases in HDL cholesterol and apoprotein-A1 concentrations, were observed in the intervention group (P < 0.05) but not in the comparison group. Changes in total cholesterol, LDL cholesterol, apoprotein-B, lipoprotein (a), and insulin concentrations, and in the LDL cholesterol/HDL cholesterol ratio, were not observed in either group. The lipid responses that were observed in this study provide biological evidence that validates the self-reported change in dietary intakes of fat and carbohydrate in response to the intervention efforts. The degree of change in these lipid concentrations was small and does not suggest increased cardiovascular disease risk.     

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.     

Soy isoflavones improve plasma lipids in normocholesterolemic, premenopausal women

BACKGROUND: Soy consumption is known to reduce plasma total cholesterol and LDL cholesterol in hypercholesterolemic subjects, but the responsible soy components and the effects in normocholesterolemic subjects remain unclear. OBJECTIVE: The effects of soy isoflavone consumption on plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerol, apolipoprotein A-I, apolipoprotein B, and lipoprotein(a) concentrations and on LDL peak particle diameter were examined in normocholesterolemic, premenopausal women. DESIGN: Thirteen healthy, normocholesterolemic, free-living, premenopausal female volunteers took part in this randomized, crossover-controlled trial. Each subject acted as her own control. Three soy isoflavone intakes (control: 10.0 +/- 1.1; low: 64.7 +/- 9.4; and high: 128.7 +/- 15.7 mg/d), provided as soy protein isolate, were consumed for 3 menstrual cycles each. Total cholesterol, HDL cholesterol, LDL cholesterol, and triacylglycerol were measured over the menstrual cycle. Apolipoprotein A-I, apolipoprotein B, lipoprotein(a), and LDL peak particle diameter were evaluated in the midluteal phase. RESULTS: Total cholesterol, HDL-cholesterol, and LDL-cholesterol concentrations changed significantly across menstrual cycle phases (P < 0.005). During specific phases of the cycle, the high-isoflavone diet lowered LDL cholesterol by 7.6-10.0% (P < 0.05), the ratio of total cholesterol to HDL cholesterol by 10.2% (P < 0.005), and the ratio of LDL to HDL cholesterol by 13.8% (P < 0.002). CONCLUSIONS: Isoflavones significantly improved the lipid profile across the menstrual cycle in normocholesterolemic, premenopausal women. Although of small magnitude, these effects could contribute to a lower risk of developing coronary heart disease in healthy people who consume soy over many years.     

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.     

Replacing cows' with sheep's dairy fat lowers plasma cholesterol concentration in participants consuming dairy fat-rich diets

OBJECTIVE: To determine the effects on plasma cholesterol concentration of replacing cows' dairy fat with sheep's dairy fat. DESIGN: Randomised crossover dietary intervention. SETTING: General community, Dunedin, New Zealand. SUBJECTS: Volunteer sample of 41 healthy adults with initial plasma cholesterol concentration between 4.8 and 7.8 mmol/l. INTERVENTIONS: Participants were asked to follow a self-selected low-fat background diet throughout the study to which, during each of the 2, 3-week dairy diets, they were asked to add sheep's or cows' dairy products. MAIN OUTCOME MEASURES: Energy and nutrient intakes, plasma triacylglycerol fatty acids, and plasma cholesterol. RESULTS: Energy and nutrient intakes on the sheep-dairy and cow-dairy diets were very similar, with total, saturated, monounsaturated and polyunsaturated fat contributing 34, 18-19, 9, and 3% of total energy intake, respectively. Participants consumed approximately 50 g/day of dairy fat on each diet. Replacing cows' with sheep's dairy fat led to a 0.33 (0.11-0.56, 95% CI) mmol/l decrease (6%) in plasma total cholesterol concentration, from 5.53 (0.90, s.d.) to 5.20 (0.90) mmol/l. Plasma low-density lipoprotein (LDL) cholesterol was 0.18 (0.02-0.33) mmol/l lower on the sheep-dairy diet as was the concentration of plasma high-density lipoprotein (HDL) cholesterol, 0.11 (0.02-0.20) mmol/l. The LDL to HDL cholesterol ratio at the end of the sheep-dairy diet, 2.91 (1.10), was not significantly different (P>0.05) from the cow-dairy diet, 2.73 (0.83). CONCLUSIONS: Within the context of a diet high in dairy fat (50 g/day), replacing cows' milk fat with sheep's milk fat leads to a small reduction in plasma cholesterol concentration, but no change in the ratio of LDL to HDL cholesterol.     

Soy isoflavones improve plasma lipids in normocholesterolemic and mildly hypercholesterolemic postmenopausal women

BACKGROUND: Soy-protein consumption is known to reduce plasma total and LDL cholesterol concentrations. However, the responsible soy component or components and the magnitude of effects in normocholesterolemic and mildly hypercholesterolemic subjects are unclear. OBJECTIVE: The present study examined the effects of soy isoflavone consumption on plasma concentrations of triacylglycerol, apolipoprotein (apo) A-I, apo B, lipoprotein(a), and total, LDL, and HDL cholesterol and on LDL peak particle diameter in normocholesterolemic and mildly hypercholesterolemic postmenopausal women. DESIGN: In a randomized crossover trial, fasting plasma samples were obtained from 18 postmenopausal women throughout three 93-d periods of daily isolated soy protein (ISP) consumption providing an average of 7.1 +/- 1.1 (control), 65 +/- 11 (low isoflavone), or 132 +/- 22 (high isoflavone) mg isoflavones/d. RESULTS: Compared with values measured during the control diet, the plasma LDL cholesterol concentration was 6.5% lower (P < 0.02) during the high-isoflavone diet and the ratio of LDL to HDL cholesterol was 8.5% and 7.7% lower during the low- and high-isoflavone diets, respectively (P < 0.02). Isoflavone consumption did not significantly affect plasma concentrations of total or HDL cholesterol, triacylglycerol, apo A-I, apo B, or lipoprotein(a) or the LDL peak particle diameter. CONCLUSIONS: Consumption of isoflavones as a constituent of ISP resulted in small but significant improvements in the lipid profile in normocholesterolemic and mildly hypercholesterolemic postmenopausal women. Although the effects were small, it is possible that isoflavones may contribute to a lower risk of coronary heart disease if consumed over many years in conjunction with other lipid-lowering strategies.     

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.     

Gene-diet interactions and plasma lipoproteins: role of apolipoprotein E and habitual saturated fat intake

To test whether plasma lipoprotein levels and low density lipoprotein (LDL) particle size are modulated by an interaction between habitual saturated fat intake and apolipoprotein E (APOE) genotype, we studied 420 randomly selected free-living Costa Ricans. The APOE allele frequencies were 0.03 for APOE2, 0.91 for APOE3, and 0.06 for APOE4. The median saturated fat intake, 11% of energy, was used to divide the population into two groups, LOW-SAT (mean intake 8.6% energy) represents those below median intake, and HIGH-SAT (mean intake 13.5%) represents those above median intake. Significant interactions between APOE genotype and diet were found for VLDL (P = 0.03) and HDL cholesterol (P = 0.02). Higher saturated fat intake was associated with higher VLDL cholesterol (+29%) and lower HDL cholesterol (-22%) in APOE2 carriers, while the opposite association was observed in APOE4 carriers (-31% for VLDL cholesterol and +10% for HDL cholesterol). Higher saturated fat intake was associated with smaller LDL particles (-2%, P < 0.05) in APOE2 carriers, and larger LDL particles (+2%, P < 0.05) in APOE4 carriers, but the gene-diet interaction was not statistically significant (P = 0.09). Higher saturated fat intake was associated with higher LDL cholesterol in all genotypes (mean +/- SEM, LOW-SAT 2.61 +/- 0.05 vs. HIGH-SAT 2.84 +/- 0.05 mmol/L, P = 0.009). These data suggest that the APOE2 allele could modulate the effect of habitual saturated fat on VLDL cholesterol and HDL cholesterol in a population with an average habitual total fat intake of less than 30%.     

Breast cancer risk factors in two distinct ethnic groups: Indian and Pakistani vs. American premenopausal women

Asian Indians from the Indian subcontinent have low rates of breast cancer, but studies on breast cancer risk factors in Indian and Pakistani women living in the United States are lacking. This study contrasted breast cancer risk factors [serum total 17 beta-estradiol (E2), sex hormone-binding globulin-bound E2, available E2, estrone (E1), and dehydroepiandrosterone sulfate, reproductive history, family history of cancer, body composition/size, dietary intake, physical activity, and excretion of isoflavones] between two distinct ethnic groups of premenopausal women residing in the United States. We also determined the contribution of these and other factors to the variability of each sex hormone. Distributions of values for serum total E2, available E2, and sex hormone-binding globulin-bound E2 (%) were greater (p < 0.005) in American (n = 47) than in Indian and Pakistani (n = 47) women. Multiple regression analysis indicated that 26% of the variability (p < or = 0.0001) in serum E2 was accounted for by the ratio of total cholesterol to high-density-lipoprotein cholesterol, length of time in the United States, and saturated fat intake, whereas less (17%) variability was accounted for by available E2 (representing free E2 + albumin-bound E2), contributed by the ratio of total cholesterol to high-density-lipoprotein cholesterol and saturated fat intake. Five variables accounted for 31% of the variability (p < or = 0.0001) in E1. The major finding of this study was that circulating sex hormone concentrations were determined more by environmental factors than by ethnicity, which was not a significant contributor to any of the serum hormones.     

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.     

A very low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins

BACKGROUND: We found previously that men with a predominance of large LDL particles (phenotype A) consuming high-fat diets (40-46% fat) show less lipoprotein benefits of low-fat diets (20-24% fat) than do men with a high-risk lipoprotein profile characterized by a predominance of small LDL (phenotype B). Furthermore, one-third of men with phenotype A consuming a high-fat diet converted to phenotype B with a low-fat diet. OBJECTIVE: We investigated effects of further reduction in dietary fat in men with persistence of LDL subclass phenotype A during both high- and low-fat diets. DESIGN: Thirty-eight men who had shown phenotype A after 4-6 wk of both high- and low-fat diets consumed for 10 d a 10%-fat diet (2.7% saturates) with replacement of fat with carbohydrate and no change in cholesterol content or ratio of polyunsaturates to saturates. RESULTS: In 26 men, phenotype A persisted (stable A group) whereas 12 converted to phenotype B (change group). LDL cholesterol did not differ from previous values for 20-24%-fat diets in either group, whereas in the change group there were higher concentrations of triacylglycerol and apolipoprotein B; greater mass of HDL, large LDL-I, small LDL-III and LDL-IV, and HDL3; lower concentrations of HDL cholesterol, apolipoprotein A-I; and lower mass of large LDL-I and HDL2. CONCLUSIONS: There is no apparent lipoprotein benefit of reduction in dietary fat from 20-24% to 10% in men with large LDL particles: LDL-cholesterol concentration was not reduced, and in a subset of subjects there was a shift to small LDL along with increased triacylglycerol and reduced HDL-cholesterol concentrations.     

Dairy fat in cheese raises LDL cholesterol less than that in butter in mildly hypercholesterolaemic subjects

OBJECTIVE: To determine whether dairy fat in cheese raises low-density lipoprotein (LDL) cholesterol as much as in butter, since epidemiology suggests a different impact on cardiovascular disease. DESIGN: A randomised crossover trial testing the daily consumption of 40 g dairy fat as butter or as matured cheddar cheese, each of 4 weeks duration, was preceded by and separated by 2-week periods when dietary fat was less saturated. SETTING: Free-living volunteers. SUBJECTS: A total of 14 men and five women of mean age 56+/-8 y, with mean total cholesterol of 5.6+/-0.8 mmol/l. MAIN OUTCOME MEASURES: Plasma cholesterol, LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triacylglycerol and glucose. RESULTS: Saturated fat intake was significantly lower during the run-in than during the cheese and butter periods. Mean lipid values did not differ significantly between the cheese and run-in periods, but total cholesterol and LDL-C were significantly higher with butter: total cholesterol (mmol/l): butter 6.1+/-0.7; run-in 5.6+/-0.8 (P < 0.05; ANOVA with Bonferroni adjustment); vs cheese 5.8+/-0.6 (P > 0.05); median LDL-C (mmol/l): butter 3.9 (3.5-4.1) vs run-in 3.4 (3.0-4.1) (P < 0.05; Tukey test); vs cheese 3.7 (3.3-3.9) (P > 0.05). Among 13 subjects whose initial LDL-C was >4 mmol/l, the difference between butter (4.4+/-0.3 mmol/l) and cheese (3.9+/-0.3 mmol/l) was significant (P = 0.014). HDL-C was highest with butter and triacylglycerol with cheese (neither was significant). CONCLUSION: A total of 40 g dairy fat eaten daily for 4 weeks as butter, but not as cheese, raised total and LDL cholesterol significantly compared with a diet containing significantly less saturated fat. Dietary advice regarding cheese consumption may require modification.     

Effects of medium-chain fatty acids and oleic acid on blood lipids, lipoproteins, glucose, insulin, and lipid transfer protein activities

BACKGROUND: Dietary medium-chain fatty acids (MCFAs) are of nutritional interest because they are more easily absorbed from dietary medium-chain triacylglycerols (MCTs) than are long-chain fatty acids from, for example, vegetable oils. It has generally been claimed that MCFAs do not increase plasma cholesterol, although this claim is poorly documented. OBJECTIVE: We compared the effects of a diet rich in either MCFAs or oleic acid on fasting blood lipids, lipoproteins, glucose, insulin, and lipid transfer protein activities in healthy men. DESIGN: In a study with a double-blind, randomized, crossover design, 17 healthy young men replaced part of their habitual dietary fat intake with 70 g MCTs (66% 8:0 and 34% 10:0) or high-oleic sunflower oil (89.4% 18:1). Each intervention period lasted 21 d, and the 2 periods were separated by a washout period of 2 wk. Blood samples were taken before and after the intervention periods. RESULTS: Compared with the intake of high-oleic sunflower oil, MCT intake resulted in 11% higher plasma total cholesterol (P = 0.0005), 12% higher LDL cholesterol (P = 0.0001), 32% higher VLDL cholesterol (P = 0.080), a 12% higher ratio of LDL to HDL cholesterol (P = 0.002), 22% higher plasma total triacylglycerol (P = 0.0361), and higher plasma glucose (P = 0.033). Plasma HDL-cholesterol and insulin concentrations and activities of cholesterol ester transfer protein and phospholipid transfer protein did not differ significantly between the diets. CONCLUSIONS: Compared with fat high in oleic acid, MCT fat unfavorably affected lipid profiles in healthy young men by increasing plasma LDL cholesterol and triacylglycerol. No changes in the activities of phospholipid transfer protein and cholesterol ester transfer protein were evident.     

A solid dietary fat containing fish oil redistributes lipoprotein subclasses without increasing oxidative stress in men

There is a demand and need for healthy solid dietary fats. However, synthetic fats can be tailored to contain specific physiologic properties. Our goal was to design dietary solid test fats that would be both beneficial to the atherogenic lipid profile and stable against lipid peroxidation. Sixteen men (age 35-75 y) substituted 80 g of their normal dietary fat intake with test fat for two periods of 21 d each in a double-blind, randomized, crossover study. Although solid, both test fats were low in cholesterol-raising SFA. Test fat "F" contained 5 g/100 g long chain (n-3) fatty acids matched by oleic acid in test fat "O." Plasma total triacylglycerol (TAG), VLDL TAG, cholesterol in VLDL, and intermediate density lipoproteins (IDL) were lower (P < 0.05), whereas apolipoprotein (apo) B of the large LDL-2 (d = 1031-1042 g/L) subclass, and cholesterol of HDL(2b) subclass, were higher after intake of F than O fat (P < 0.05). There was no difference in the effect on in vivo oxidation measured as the ratio of plasma isoprostanes F(2) to arachidonic acid and urinary isoprostanes, whereas the vitamin E activity/plasma total lipids ratio was higher after intake of F than O (P = 0.008). In conclusion, a solid dietary fat containing (n-3) PUFA decreased plasma TAG, VLDL, and IDL cholesterol, and redistributed lipoprotein subclasses in LDL and HDL, with a higher concentration of the larger and less atherogenic subfractions. These changes took place without an increase in oxidative stress as measured by in vivo markers.     

High-fiber oat cereal compared with wheat cereal consumption favorably alters LDL-cholesterol subclass and particle numbers in middle-aged and older men

BACKGROUND: No studies have examined whether increased consumption of oat cereal, rich in soluble fiber, favorably alters lipoprotein particle size and number. OBJECTIVE: We examined the effects of large servings of either oat or wheat cereal on plasma lipids, lipoprotein subclasses, lipoprotein particle diameters, and LDL particle number. DESIGN: Thirty-six overweight men aged 50-75 y were randomly assigned to consume daily for 12 wk either oat or wheat cereal providing 14 g dietary fiber/d. Before and after the intervention, plasma lipid and lipoprotein subclasses were measured with proton nuclear magnetic resonance spectroscopy, and whole-body insulin sensitivity was estimated with the frequently sampled intravenous-glucose-tolerance test. RESULTS: Time-by-treatment interactions (P < 0.05) for LDL cholesterol (oat: -2.5%; wheat: 8.0%), small LDL cholesterol (oat: -17.3%; wheat: 60.4%), LDL particle number (oat: -5.0%; wheat: 14.2%), and LDL:HDL cholesterol (oat: -6.3%; wheat: 14.2%) were observed. Time-by-treatment interactions were nearly significant for total cholesterol (oat: -2.5%; wheat: 6.3%; P = 0.08), triacylglycerol (oat: -6.6%; wheat: 22.0%; P = 0.07), and VLDL triacylglycerol (oat: -7.6%; wheat: 2.7%; P = 0.08). No significant time-by-treatment interactions were observed for HDL cholesterol, HDL-cholesterol subclasses, or LDL, HDL, and VLDL particle diameters. Insulin sensitivity did not change significantly with either intervention. CONCLUSIONS: The oat compared with the wheat cereal produced lower concentrations of small, dense LDL cholesterol and LDL particle number without producing adverse changes in blood triacylglycerol or HDL-cholesterol concentrations. These beneficial alterations may contribute to the cardioprotective effect of oat fiber.     

Dietary intake and gene variation influence the response of plasma lipids to dietary intervention.

We have examined whether variation at the apolipoprotein (apo) B, apo E, apo AII, and apo AI-CIII-AIV genes affected the relationship between dietary intake and serum lipid traits in individuals who had participated in dietary intervention from a basal high fat diet to a low fat diet followed by a return to their natural diet, the switchback. On both the basal and switchback diets where the variance of dietary intake was great, there was a significant correlation between P/S ratio and serum total, low-density lipoprotein (LDL) cholesterol, and apo AI levels. In addition dietary cholesterol (dchol) levels correlated significantly with serum apo AI levels on the basal diet. Comparing the difference between basal and intervention (delta 1) and between switchback and intervention diets (delta 2), changes in dchol and P/S ratio correlated significantly with changes in serum total, high-density lipoprotein (HDL) and LDL cholesterol, and apo B levels. There was a significant correlation between monounsaturated fatty acid (MUFA) and apo AI levels during both changes. Furthermore we have examined whether the relationship between variables was homogeneous among genotypes of candidate gene polymorphisms. A heterogeneous effect (P less than 0.01) was seen among genotypes of the PvuII-AIV restriction fragment length polymorphism (RFLP) on the correlation of serum LDL cholesterol levels and dietary MUFA during both dietary changes (delta 1 and delta 2). A heterogeneous effect among genotypes of the apo B XbaI RFLP on the correlation between dchol versus total and LDL cholesterol during the change delta 1, but not delta 2, was observed. Thus our results show that both dietary components and genetic variation affect the response of serum lipid, lipoprotein, and apolipoprotein levels to dietary change.     

Effects of weight loss on changes in insulin sensitivity and lipid concentrations in premenopausal African American and white women

BACKGROUND: Few studies have tested the hypothesis that changes in disease risk factors are more closely associated with changes in visceral fat than with changes in other adipose tissue depots, particularly in subjects with different ethnic or racial backgrounds. OBJECTIVE: We describe changes in triacylglycerol, total cholesterol, HDL cholesterol, LDL cholesterol, insulin sensitivity (S(i)), visceral fat, and subcutaneous abdominal adipose tissue (SAAT) with weight loss in premenopausal, overweight [body mass index (in kg/m(2)): 27-30], African American (n = 19) and white (n = 18) women. DESIGN: Assessments were performed before and after diet-induced weight loss to a BMI < 25. Body composition and body fat distribution were assessed with dual-energy X-ray absorptiometry and computed tomography, respectively; S(i) was assessed with an intravenous-glucose-tolerance test and minimal modeling. RESULTS: White women lost significantly more visceral fat and less SAAT than did African American women despite similar weight losses (approximately 13 kg). Mixed-model analysis indicated significant effects of time (ie, weight loss) on S(i), triacylglycerol, HDL cholesterol, and LDL cholesterol and of race on triacylglycerol. Time x race interaction terms were not significant. After adjustment for either total body or visceral fat, time was not related to any outcome variable; however, race remained significantly related to triacylglycerol. CONCLUSIONS: With weight loss, moderately overweight African American and white women experienced significant improvements in S(i) and lipids. The beneficial effects of weight loss did not differ with race and could not be attributed to a specific body fat depot. Lower triacylglycerol concentrations among African American women are independent of both obesity status and body fat distribution.     

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.     

Changes in women's plasma lipid and lipoprotein concentrations due to moderate consumption of alcohol are affected by dietary fat level.

We studied the impact of substituting ethanol for dietary carbohydrate, in high- and low-fat diets, on plasma lipids and lipoprotein concentrations. During a 12-wk, weight maintaining, controlled feeding study, women consumed only food and beverage provided by the Human Studies Facility of the USDA Beltsville Human Nutrition Research Center. Twenty-six women (age 41-59 y) consumed either a high-fat diet (38% of energy from fat) or a low-fat diet (18% of energy from fat) for 12 wk. The 12-wk feeding period was divided into two 6-wk periods in a cross-over design during which either ethanol or carbohydrate was added to the diet (5% of total daily energy intake). When the women consuming the high-fat diet had ethanol added to their diet, they had 6% lower plasma cholesterol (P = 0.003), 11% lower LDL cholesterol (P = 0.001) and 3% higher HDL cholesterol (P = 0.06) than when they had an equal amount (% energy) of carbohydrate added to their diet. The greater HDL cholesterol concentration was due to a 21% greater the HDL(2) subfraction (P = 0. 001). The ratio of LDL to HDL cholesterol was 14% lower. No significant differences existed in plasma lipids in women consuming the low-fat diet between the periods in which they had ethanol or carbohydrate added to their diet. This study suggests that the decreases in cardiovascular disease risk factors typically seen with moderate alcohol consumption may not be evident in individuals consuming a diet low in fat. Therefore changes in the risk factors associated with a low-fat diet and moderate alcohol consumption do not appear to be additive.