Interactions of dietary fat intake and the hepatic lipase -480C-->T polymorphism in determining hepatic lipase activity: the Hoorn Study

BACKGROUND: Gene-nutrient interactions affecting hepatic lipase (HL) activity may contribute to the interindividual variability of the cardiovascular disease risk associated with dietary fat intake. OBJECTIVE: We determined the associations of dietary fat intake with postheparin HL activity and the possible modifying effect of the HL -480C-->T polymorphism on these associations. DESIGN: Subjects were recruited from participants in the 2000-2001 follow-up examination of the Hoorn Study. HL activity was determined in postheparin plasma in a sample of 211 men and 218 women aged 60-87 y. Information about dietary intake of the participants was obtained with a validated food-frequency questionnaire. Linear regression was performed, adjusted for age. RESULTS: Total dietary fat was positively associated with HL activity (standardized beta: 0.11; 95% CI: 0.02, 0.21), and this association was also seen for saturated fat (0.10; 0.01, 0.20) and monounsaturated fatty acid (0.10; 0.01, 0.19). We observed a significant interaction of the HL polymorphism with the relation between total fat intake and HL activity. The association of total fat with HL activity was stronger in subjects with CT (0.27; 0.11, 0.43) and TT (0.39; -0.22, 1.00) genotypes than in subjects with the CC genotype (0.06; -0.06, 0.18; P for interaction < 0.10). The interaction remained statistically significant in models that included age, sex, carbohydrate and protein intakes, and insulin or body mass index. CONCLUSIONS: Higher intakes of total and saturated fat were positively associated with higher HL activity. In addition, the observed association of total fat with HL activity was modified by the HL-480C-->T polymorphism, after adjustment for age, sex, carbohydrate and protein intakes, and insulin or body mass index.     

Lipoprotein lipase activity and chylomicron clearance in rats fed a high fat diet

The relationships of tissue and plasma lipoprotein lipase (LPL) activities to tissue uptake and plasma clearance of 14C-labeled chylomicron-triglyceride (14C-CM-TG) were studied in female rats fed isoenergetic and isonitrogenous control (12% kJ from fat) or high fat diets (72% kJ from fat) for 8 wk. Animals fed the high-fat diet had higher levels of fasting plasma triglycerides and lower LPL activities in heart, renal adipose tissue and post-heparin plasma. Changes in LPL activities of skeletal muscles varied among muscles with higher values in the soleus and plantaris (32-61%) and no differences in the gastrocnemius. The lower LPL activity in renal adipose tissue was associated with lower uptake of fatty acids from 14C-CM-TG by adipose. Fatty-acid uptake from labeled TG was not associated with tissue LPL activity in other tissues. Clearance of 14C-CM-TG from plasma and the half-lives of 14C-CM-TG were similar in both dietary groups. These data indicate that tissue and plasma LPL activities are not a direct index of uptake of fatty acids by tissues or clearance of chylomicron triglycerides.     

Effect of highly active antiretroviral therapy on fat, lean, and bone mass in HIV-seropositive men and women.

BACKGROUND: Alterations in body composition have been reported in HIV-positive adults receiving highly active antiretroviral therapy (HAART), but the magnitude and potential determinants of these changes are unclear. OBJECTIVE: We compared total and regional body composition, as measured by dual-energy X-ray absorptiometry, in 203 HIV-positive men and 62 HIV-positive women according to HAART. DESIGN: This was a cross-sectional analysis of a cohort study of nutrition and HIV infection. RESULTS: After adjustment for age, weight, race, and exercise habits, total weight and fat mass did not differ significantly in men or women by HAART. Trunk fat was greater in men (1.0 kg; P < 0.001) and women (1.4 kg; P = 0.005) and leg fat was lower in men (-1.0 kg; P < 0.001) and women (-1.5 kg, P = 0.005) receiving HAART than in those not. This corresponded to a greater percentage of total fat mass located in the trunk (men: 7.5%, P < 0.001; women: 5.1%, P = 0.02). Lean mass was also greater with longer duration of HAART in men (P < 0.002). In men receiving HAART, total and regional bone mineral content were less than in the men not receiving HAART (P < 0.001). These effects increased with longer duration of HAART. Protease inhibitors were associated with the largest differences in regional fat. CONCLUSIONS: HAART is associated with redistribution of fat mass from the legs to the trunk, despite no significant differences in total fat mass or weight. In men, HAART is also associated with a reduction in bone mineral content, suggesting that HAART increases the risk of central obesity and osteoporosis.     

Age-related decrease in resting energy expenditure in sedentary white women: effects of regional differences in lean and fat mass

BACKGROUND: Lean mass and resting energy expenditure (REE) decrease with age. However, it is unknown whether age-related changes in regional lean and fat mass are responsible for the age-related decrease in REE. OBJECTIVE: Our objective was to determine how regional lean and fat mass vary with age and whether age is independently related to REE after adjustment for regional fat and lean mass. DESIGN: The study was a cross-sectional evaluation of 58 white women aged 23-77 y. Regional and whole-body lean and fat mass were measured by dual-energy X-ray absorptiometry, subcutaneous abdominal tissue (SAT) and intraabdominal adipose tissue (IAF) by computed tomography, and REE by ventilated-canopy indirect calorimetry. RESULTS: Independent of other significant correlates, age was significantly and independently associated with greater IAF (beta = 0.49) and less leg lean mass (beta = -0.35). IAF (r = -0.28) and IAF:SAT (r = -0.31) correlated negatively with REE. REE was negatively associated with greater age (beta = -0.42), independent of changes in lean and fat mass in different parts of the body. By contrast, trunk lean (beta = 0.27) and leg fat (beta = 0.27) mass were associated with greater REE independent of age and other body-composition variables. CONCLUSIONS: These results suggest that trunk lean mass (presumably primarily organ tissue) is relatively resistant to age-related changes in body composition, whereas muscle mass, especially leg muscle, tends to be lost. These data also suggest that the age-related decreases in REE are not fully explained by changes in body composition.     

Lipoprotein lipases, lipoproteins and tissue lipids in rats fed fish oil or coconut oil

The effect of fish oil and coconut oil on plasma lipoproteins and lipoprotein-catabolizing enzymes [lipoprotein lipase (LPL) and hepatic endothelial lipase (HL)] was studied in rats. Male rats were fed for 4 wk purified diets containing equienergetic, amounts of either coconut oil (group A), coconut oil:fish oil, 50:50 (group B) or fish oil (group C). Whole plasma triacylglycerol, cholesterol and phospholipid concentrations were appreciably lower in group C than in group A, mainly due to a fall in very low density lipoprotein (VLDL) and subgroup 2 of high density lipoprotein (HDL2), with less consistent changes in LDL and HDL3. VLDL components of group B were also considerably lower than corresponding ones in group A. LPL and HL activities were about 50% lower in groups B and C than in group A. Increased hepatic triacylglycerol and cholesterol concentrations were observed in groups B and C. It is suggested that the decrease in LPL and HL activity of fish oil-fed rats may be an adaptive response to the low concentration of the substrate (triacylglycerols) for these enzymes.     

Interactions between the -514C->T polymorphism of the hepatic lipase gene and lifestyle factors in relation to HDL concentrations among US diabetic men

BACKGROUND: Low plasma HDL-cholesterol concentrations are a hallmark of diabetic dyslipidemia. A common polymorphism (-514C-->T) of the hepatic lipase gene (LIPC), which accounts for up to 30% of the variation in hepatic lipase activity, has been associated with low hepatic lipase activity and high HDL-cholesterol concentrations. OBJECTIVE: We examined the association between this polymorphism and plasma HDL-cholesterol concentrations and evaluated whether this association was modified by adiposity and dietary fat intake. DESIGN: We followed men aged 40-75 y who participated in the Health Professionals Follow-Up Study in 1986. Among 18 159 men who returned blood samples by 1994, 780 had confirmed type 2 diabetes at blood drawing or during follow-up to 1998 and were free of cardiovascular disease at blood drawing. RESULTS: After adjustment for age, smoking, alcohol consumption, fasting status, glycated hemoglobin concentration, physical activity, and body mass index, HDL-cholesterol concentrations were significantly higher in men with the C/T or T/T genotype than in those with the C/C genotype (adjusted x: 40.9 and 38.8 mg/dL, respectively; P = 0.01). We observed significant LIPC -514 polymorphism x body mass index and LIPC -514 polymorphism x saturated fat intake interactions for HDL-cholesterol concentrations (P = 0.003 for both). The T allele was associated with higher HDL-cholesterol concentrations only in men who were not overweight or who had higher saturated fat intake. CONCLUSION: Our study suggests that the effects of -514C-->T of the LIPC gene on HDL concentrations were modified by saturated fat intake and obesity.     

Postheparin lipolytic activity and plasma lipoprotein response to omega-3 polyunsaturated fatty acids in patients with primary hypertriglyceridemia

The hypotriglyceridemic action of omega-3 (n-3) fatty acids is attributed primarily to reduction in hepatic triglyceride synthesis and reduced secretion of very-low-density lipoproteins (VLDLs). However, increased catabolism of triglyceride-rich lipoproteins was reported and could be due to increased availability of peripheral lipoprotein lipase (LPL) or hepatic lipase (HL). In this study plasma lipoproteins and postheparin activities of LPL and HL were determined in 12 patients with primary hypertriglyceridemia before and during isocaloric substitution of omega-3 fatty acids (10 g/d) for 4 wk. Omega-3 polyunsaturates resulted in 53% and 61% reductions in plasma triglyceride and VLDL-cholesterol concentrations, respectively (P less than 0.0001). However, low-density-lipoprotein (LDL)-cholesterol concentrations increased by 26% (P less than 0.001). Activities of postheparin LPL and HL essentially remained the same. Thus, in patients with primary hypertriglyceridemia, reduction in plasma triglyceride concentrations and increase in LDL-cholesterol concentrations mediated by omega-3 polyunsaturates seem to occur without an increase in LPL or HL activities.     

A high dietary lipid intake during pregnancy and lactation enhances mammary gland lipid uptake and lipoprotein lipase activity in rats.

Rats fed a diet with high fat concentration produce larger amounts of milk with a higher lipid concentration than rats fed a lower fat diet. This investigation was designed to study the relationship between dietary fat intake, mammary gland lipid uptake and lipogenesis in rat dams fed, during pregnancy and lactation, one of two purified diets, with equal energy density, containing 2.5 (LL) or 20 g fat/100 g diet (HL). Milk lipid concentration and fatty acid composition were determined at d 14 of lactation. Mammary gland lipogenesis, lipoprotein lipase (LPL) activity and the uptake of [1-(14)C]triolein by the mammary gland and its transfer to the pups was measured. The intestinal absorption of oral (14)C-lipid, (14)CO(2) production and the amount of (14)C-lipid transferred to the pups (milk clot + pups carcass) were significantly higher in the HL group than in the LL group (P < 0.05). Mammary gland lipogenesis was 75% lower and LPL activity was 30% higher in the HL group (P < 0.05). Medium-chain fatty acids (C6-C14) excretion was 46% lower and that of long-chain fatty acids was 142% (P < 0.001) higher in the HL group than in the LL group. The higher milk lipid excretion in the rats fed a high-fat diet resulted from a larger uptake of dietary lipid by the mammary gland, indicated by a larger transfer of (14)C-lipid to the pups and by a higher LPL activity in the mammary gland.     

The impact of the leucine 7 to proline 7 polymorphism of the neuropeptide Y gene on postprandial lipemia and on the response of serum total and lipoprotein lipids to a reduced fat diet

OBJECTIVE: The aim of the study was to examine the impact of the leucine7 to proline7 (Leu7Pro) polymorphism of the NPY gene on postprandial (PP) lipemia, post-heparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities, and the response of serum lipids to a reduced fat diet. DESIGN AND SUBJECTS: Seven middle-aged obese subjects with Leu7Pro genotype were matched with seven subjects with Leu7Leu genotype for gender, age, apolipoprotein E phenotype and BMI. These 14 subjects participated in the oral 8 h fat tolerance test. Sixty-eight slightly obese middle-aged subjects (10 with the Leu7Pro genotype) had participated in intervention studies and consumed a reduced fat diet for 8 weeks. RESULTS: There were no statistically significant differences in PP areas under the curve of plasma total triglycerides (TG), chylomicron TG, VLDL-TG or insulin between the genotype groups. The TG-to-cholesterol (C) ratio in VLDL was significantly lower in the subjects with Leu7Pro genotype compared to those with the Leu7Leu genotype at time points 30 min and 1 h in the fat tolerance test. Heparin-induced activities of LPL or HL or the response of serum total or LDL-C to the reduced fat diet did not differ between the groups. CONCLUSIONS: The NPY genotype neither affects the magnitude of postprandial lipemia induced by a fat tolerance test nor the response of serum total lipids or lipids in different lipoprotein classes to the reduced fat diet. However, this preliminary study suggests that there might be compositional differences in the lipoprotein particles between the genotype groups that affect postprandial lipid metabolism. SPONSORSHIP: The Council for Health Sciences of the Academy of Finland, Kuopio University Hospital and the National Technology Agency, Finland.     

Nutritional risk assessment and obesity in rural older adults: a sex difference

BACKGROUND: Many older Americans are overweight or obese, but it is unclear whether obesity is associated with other nutritional risk indicators. OBJECTIVE: This study investigated sex-associated differences in nutritional risk among community-dwelling, rural older adults and determined whether weight status [body mass index (BMI; in kg/m(2)) and waist circumference] was related to other measures of nutritional risk. DESIGN: This cross-sectional study explored relations between weight status and nutritional risk, which was determined on the basis of the Level II Screen, overall diet quality, nutrient intakes, and plasma biomarkers. RESULTS: Of the 179 subjects, 44% were overweight (BMI 25-29.9) and 35% were obese (BMI > 30). There were few differences in nutrient intakes between older men and women after we controlled for energy intake. In women, BMI was directly associated with multiple additional nutritional risk indicators, including the number of Level II items (r = 0.30), intakes of fat (r = 0.26) and saturated fat (r = 0.21), and homocysteine concentration (r = 0.25). Weight status in women was inversely associated with intakes of carbohydrates (r = -0.25), fiber (r = -0.35), folate (r = -0.24), magnesium (r = -0.29), iron (r = -0.22), and zinc (r = -0.23); Healthy Eating Index scores (r = -0.22); and plasma pyridoxal 5' phosphate (r = -0.30). Associations with waist circumference were similar. In men, weight status was associated only with plasma cobalamin (r = -0.33 for BMI) and pyridoxal 5' phosphate (r = -0.24 for waist circumference). CONCLUSIONS: Overweight and obese older women, particularly those living alone, may be at greater nutritional risk than are men with a high BMI. Targeted nutritional intervention emphasizing nutrient-dense food choices to improve dietary patterns may be warranted.     

Association of a Pvull RFLP at the lipoprotein lipase locus with fasting insulin levels in Hispanic men

We present results from an association study between RFLPs in the lipoprotein lipase (LPL) gene and lipid and insulin levels. The study population consisted of 102 Hispanic men and 97 Hispanic women. The subjects were genotyped for two previously reported RFLPs detected with the restriction enzymes HindIII and PvuII. The frequencies of the RFLPs in the Hispanic population are similar to those seen in other Caucasian populations. Strong linkage disequilibrium was detected between the sites in Hispanics. Genotypes were used separately in analyses of variance with fasting serum triglycerides, total cholesterol, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, HDL₂/HDL₃-cholesterol, and insulin levels, as well as two measures of adiposity: waist-hip ratio and body mass index. Men and women were analyzed separately. Mean fasting insulin levels of the LPL PvuII genotypes were significantly different from each other in Hispanic men. The mean fasting insulin level of men who were homozygous for the presence of the PvuII site (+/+) was 9.20 ± 0.24 μunits/ml, men who were heterozygous had a mean level of 10.54 ± 0.20 μunits/ml, and men who were homozygous for the absence of the site (-/-) had a mean of 12.91 ± 0.30 μunits/ml. This effect was not seen in Hispanic women. These results suggest that the regulation of LPL by insulin may be different in Hispanics with different LPL PvuII genotypes. © 1993 Wiley-Liss, Inc.     

Purified chickpea or lentil proteins impair VLDL metabolism and lipoprotein lipase activity in epididymal fat,but not in muscle,compared to casein,in growing rats

Background  It is well known that the legume proteins have a lowering effect on plasma cholesterol and triacylglycerols (TG) concentrations compared to animal proteins. The protein itself, as well as non-protein constituents, naturally present in legumes may be implicated. Aim of the study  The effects of various dietary purified legumes proteins compared to casein, were determined on plasma TG level, VLDL concentration and composition. Moreover, lipoprotein lipase (LPL) activity in epididymal fat, gastrocnemius and heart was investigated to evaluate in these tissues their capacity to release free fatty acids from their TG substrate and the liver capacity to stock the TG. Methods  Weaning male Wistar rats were fed ad libitum one of the following diets: 200 g/kg diet of purified proteins of lentil (L), or chickpea (CP) or casein (CAS). At day 28, VLDL were isolated from plasma sample by a single ultracentrifugation flotation. Hepatic lipase and LPL activity in epididymal fat, gastrocnemius and heart were measured by using glycerol tri [9–10(n)-³H] oleate emulsion as substrate. Results  Compared with CAS diet, the CP and L protein diets exhibited similar cholesterolemia, but lower triglyceridemia (1.9-fold and 2.5-fold) and VLDL particle number, as measured by their reduced contents of TG and apolipoproteins. CP and L protein diets reduced liver TG and cholesterol by 31 and 45%, respectively compared to CAS diet. Furthermore, LPL activity in adipose tissue of rats fed CP or L was 1.6-fold lower than that of rats fed CAS. There was no significant difference in heart and gastrocnemius LPL activities with the three proteins. In contrast, hepatic lipase activity was higher in rats fed CP and L diets. Conclusion  The low food efficiency ratio of purified CP and L proteins related to CAS is associated with decreased plasma VLDL and adipose tissue LPL activity. The low liver TG concomitant with reduced TG and apolipoproteins contents of VLDL confirm that hypotriglyceridemia is essentially due to impaired synthesis, exportation and transport of TG by VLDL which prevent lipid storage in adipose tissue.     

Leg fat might be more protective than arm fat in relation to lipid profile

Purpose

The objective of this study was to determine the independent relationships of trunk fat, leg fat and arm fat to cardiovascular (CVD) risk factors, after controlling for relevant confounders such as fat mass index, cardiorespiratory fitness and objectively measured physical activity.

Methods

This is a cross-sectional study involving 683 university students, aged 18–30 years. Total and regional body fat distribution was measured using dual-energy X-ray absorptiometry. The associations of trunk, leg and arm fat with CVD risk factors (triglycerides-TG-, high-density lipoprotein cholesterol-HDL-c-, TG/HDL-c ratio, HOMA_IR, mean arterial pressure, C-reactive protein) were examined using regression linear models, controlling for age, sex, fat mass index [total body fat(kg)/height(m²)], maximal oxygen consumption and physical activity by accelerometer.

Results

After controlling for fat mass index, and other confounders, higher levels of trunk fat were found to be associated with a poorer lipid profile, while higher levels of leg fat were found to be associated with a better lipid profile. We did not find any association between arm fat and lipid profile after controlling for total fatness and other confounders. Neither trunk, leg or arm fat was found to be related to insulin resistance, blood pressure or inflammation markers.

Conclusions

Our data suggest that the region where fat is accumulated might have a differential effect on lipid profile: trunk fat has an adverse effect, leg fat has a protective effect, and arm fat has no effect. The differences observed between upper- and lower-body peripheral fat depots should be further explored.     

Gender differences in lipoprotein lipase activity after acute exercise

OBJECTIVE: To determine whether gender differences exist in lipoprotein lipase (LPL) activity in response to exercise and/or insulin. Exercise and insulin are known modulators of LPL activity in men, but this is less clear in women. LPL activity may predict propensity for obesity; therefore, understanding its modulators is of considerable importance. RESEARCH METHODS AND PROCEDURES: Gender differences in skeletal muscle and adipose tissue LPL activity were determined after a single bout of exercise followed by a hyperinsulinemic/euglycemic clamp and compared with an identical rest day in healthy lean men (n = 10) and women (n = 10). Muscle and adipose tissue biopsies were obtained pre- (post-exercise vs. rest) and post-clamp. RESULTS: Basal levels of muscle and adipose tissue LPL activity were not different between men and women. There was, however, a significant gender by day interaction for muscle LPL activity (p = 0.023) and adipose tissue LPL activity (p = 0.013). In muscle, this was because of a significant increase in LPL activity on the exercise vs. rest day in men (p < 0.001) but not women. Adipose tissue LPL activity also increased significantly in men on the exercise day relative to rest day (p = 0.04) but decreased in women (p = 0.10). The hyperinulinemic/euglycemic clamp had no independent effect on tissue LPL activity, in either gender, after rest or exercise. DISCUSSION: In the 3 to 4 hours after exercise, muscle and adipose tissue LPL activity increased significantly in men, whereas LPL activity remained unchanged in women.     

Effects of an 8-week weight-loss program on cardiovascular disease risk factors and regional body composition

OBJECTIVE: To determine the influence of weight loss on multiple cardiovascular disease (CVD) risk factors. DESIGN: Overweight women (n = 12; mean 44.2% fat) and men (n = 10; mean 30.7% fat) participated in an 8 week weight-loss program that included dietary, exercise, multi-vitamin/mineral supplementation, and behavior modification components. Measurement of total and regional body composition assessed using dual energy X-ray absorptiometry (DEXA), circumferences and blood sampling for total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, homocysteine, insulin and leptin were performed before and after the weight loss intervention. RESULTS: Subjects increased their physical activity and decreased their energy intake, resulting in a mean decrease in body mass of - 4.3 +/- 3.4 kg in women and -4.7 +/- 3.1 kg in men. Fat accounted for 88 and 58% of the decrease in body mass in men and women, respectively. Proportionally, men lost significantly more fat mass from the trunk region compared to women. Serum total and LDL cholesterol were significantly decreased in men (-11 and -14%, respectively) but not women (-3 and -3%, respectively) and there were no changes in HDL cholesterol and triacylglycerols. Serum leptin was significantly decreased (-36%) and highly correlated to fat mass (r= 0.839). There were no changes in serum insulin and plasma homocysteine. CONCLUSIONS: These data indicate that short-term weight loss resulting from reducing percentage energy from fat, increasing physical activity and vitamin/mineral supplements including folic acid has a favorable effect on regional body composition and total and LDL cholesterol with minimal effects on HDL cholesterol, triacylglycerols, homocysteine and insulin and the effects are greater in men compared to women. Supplementation with folic acid or emphasis on folic acid-rich foods may be an important component of a weight loss program to prevent increases in homocysteine.     

Plasma activities of lipoprotein lipase, hepatic lipase and lecithin: cholesterol acyltransferase in patients considered for parenteral nutrition with fat emulsion

Intralipid is a fat emulsion which is widely used for intravenous nutrition in very ill patients. In order to know more about the capacity of these patients to metabolize exogenous triglycerides, the plasma activities of lipoprotein lipase (LPL), hepatic lipase (HL) and lecithin: cholesterol acyltransferase (LCAT), the key enzymes in the metabolism of serum lipoproteins were measured by a radioisotope technique in 23 critically ill patients and 20 patients with recent major surgery. Compared with normal volunteers, the activities were significantly decreased. On the other hand, the capacity to clear intravenously given Intralipid (0.1 g/kg), expressed as fractional removal rate (K2), was retained in patients. It is suggested that the measurement of K2 could not be useful to evaluate the capacity of Intralipid administration to satisfy the metabolic needs and also that its utilization must be reevaluated in terms of potential harmful effects.     

Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women

OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.     

Whole-body fat oxidation rate and plasma triacylglycerol concentrations in men consuming an ad libitum high-carbohydrate or low-carbohydrate diet

BACKGROUND: High-carbohydrate diets may increase plasma triacylglycerol concentrations either by increasing production of triacylglycerols or by reducing their clearance. OBJECTIVE: We assessed whether the changes in plasma triacylglycerol concentrations induced by dietary interventions were associated with the changes in whole-body fat oxidation rates. DESIGN: In a parallel study, 37 healthy male subjects [body mass index (in kg/m(2)): 28 +/- 5, age: 34 +/- 11 y (x +/- SD)] consumed an ad libitum high-carbohydrate (60% of energy; n = 19) or low-carbohydrate (46% of energy), high-fat (41% of energy, 23% as monounsaturated fatty acids; n = 18) diet for 7 wk. The following variables were measured before and after the dietary interventions: 1) plasma triacylglycerols before and 2, 4, 6, and 8 h after a meal (containing 40% of daily energy needs and 41% fat); 2) indirect calorimetry throughout the 8-h test; and 3) postheparin plasma lipoprotein lipase (phLPL) activity at time 8 h of the test. RESULTS: The diets induced changes in 1) body weight: -2.5 +/- 2.8 kg (P < 0.01) and -1.7 +/- 3.1 kg (P < 0.05) and 2) fasting plasma triacylglycerols: 0.0 +/- 0.4 mmol/L (NS) and -0.3 +/- 0.3 mmol/L (P < 0.05) for the high-carbohydrate and the low-carbohydrate diets, respectively. In normoinsulinemic subjects (fasting insulin < 100 pmol/L), dietary changes in postprandial triacylglycerols were significantly predicted by changes in phLPL, body weight, respiratory quotient (or fat oxidation), and the type of diet (stepwise multiple linear regression). CONCLUSION: Postprandial plasma triacylglycerol concentrations may depend at least partly on fat oxidation, body weight, and LPL activity.     

Responses of plasma lipoproteins and sex hormones to the consumption of lean fish incorporated in a prudent-type diet in normolipidemic men

OBJECTIVE: The effects of lean fish on plasma lipoproteins, postheparin plasma lipolytic activities and sex hormones were examined in 11 normolipidemic male subjects. METHODS: This study was a randomized crossover trial of two isoenergetic prudent-type diets, lean fish diet and beef, pork, veal, eggs and milk (nonfish) diet. Experimental diets provided approximately 11800 kJ--18% as proteins, 50% as carbohydrates, 32% as lipids [ratio of polyunsaturated to saturated fatty acids (P:S) of 1:1 compared with 0.5:1 in preexperimental diet], and 260 mg cholesterol/day. RESULTS: Compared with the nonfish diet, the lean fish diet induced higher plasma total and LDL apolipoprotein (apo) B and apo B:apo A-1 ratio, indicating that the substitution of lean fish for beef, veal, pork, eggs and milk provides little benefits with regard to plasma apo B concentrations in a low-fat high P:S diet. Moreover, triglycerides:apo B and cholesterol:apo B ratios of VLDL were lower following the lean fish diet than the nonfish diet, suggesting the presence of smaller very low-density lipoprotein (VLDL) particles following the consumption of lean fish. Higher plasma concentrations of sex hormone-binding globulin (SHBG), HDL2 cholesterol and HDL2:HDL3 cholesterol ratio were found with the lean fish diet compared with the nonfish diet. Negative correlations between plasma postheparin lipoprotein lipase (LPL) activity and VLDL triglycerides (n = 11, r = -0.53, p = 0.02), and between plasma postheparin LPL activity and VLDL triglycerides:apo B ratio (n = 11, r = -0.64, p = 0.02) were also observed following the lean fish diet. CONCLUSION: These results suggest that the effects of substituting lean fish for beef, veal, pork, eggs and milk on plasma lipoproteins may be partly associated with variations in plasma sex hormone status and plasma LPL activity in normolipidemic men.     

Energy costs of standard activities among Indian adults

OBJECTIVES: To estimate the energy cost of resting (RMR), sitting and standing for urban Indian adults and compare these estimates with the reported values. DESIGN: Energy costs were measured using oxylog while body fat was estimated using equipment (HBF300, OMRON Corporation, Japan) that works on the principle of bioelectrical impedance, for 24 men and 40 women, aged 20-50 y, engaged in sedentary activities. SETTINGS: Agharkar Research Institute, Pune, India. RESULTS: Mean energy cost (kJ/min) of resting (RMR), sitting and standing were significantly (P<0.01, for all) higher for men (4.01+/-0.42, 5.0+/-0.72 and 5.74+/-0.69, respectively) than women (3.54+/-0.28, 4.03+/-0.41 and 4.35+/-0.52, respectively). Gender difference increased with the level of activity, from 13% for RMR to 32% for standing. These differences reduced when adjusted (using analysis of covariance) for body weight and became non-significant on adjusting for fat-free mass (FFM) in the case of RMR and sitting activity. The measured values of energy cost (absolute and per kg weight) for these activities were similar to African subjects but lower compared to Asian or European subjects for both sexes. The stepwise regression analysis done separately by sexes showed weight (29%) in men and body mass index (44%) in women to be the best predictors of RMR, while regression analysis for combined sexes indicated FFM and height as predictors of RMR (r(2)=56%, P<0.01). If means to estimate body fat were not available, RMR could best be predicted with BMI and sex as predictors (r(2)=55%; P<0.01). This was mainly due to the fact that the sex differences in our population were more prominent in FFM than that in BMI. Our observations thus indicate the need to develop prediction equations separately for different populations owing to differences in their body compositions, especially in fat mass (FM) or FFM. CONCLUSION: The energy costs of activities were associated with body composition, especially with absolute fat-free mass, which may vary even with the same body fat percentage. Therefore, there is a need to develop separate prediction equations for different communities.