Variations in body composition and plasma lipids in response to a high-carbohydrate diet

Validation of Nutritional Approaches to Modulate Cardiovascular and Diabetic Risk Factors in Patients with Hypertriglyceridemia or Prediabetes-The MoKaRi II Randomized Controlled Study

Hypertriglyceridemia and diabetes mellitus type 2 are among the most important metabolic diseases globally. Diet plays a vital role in the development and progression of both clinical pictures. For the 10-week randomized, controlled, intervention study, 67 subjects with elevated plasma triglyceride (TG) concentrations (≥1.7 mmol/L) and 69 subjects with elevated fasting glucose concentrations (≥5.6 < 7.0 mmol/L) were recruited. The intervention groups received specially developed, individualized menu plans and regular counseling sessions to lower (A) TG or (B) fasting glucose and glycated hemoglobin A1c as well as other cardiovascular and diabetic risk factors. The hypertriglyceridemia intervention group was further supplemented with fish oil (3.5 g/d eicosapentaenoic acid + docosahexaenoic acid). The two control groups maintained a typical Western diet. Blood samples were taken every 2 weeks, and anthropometric data were collected. A follow-up examination was conducted after another 10 weeks. In both intervention groups, there were comparable significant reductions in blood lipids, glucose metabolism, and anthropometric parameters. These results were, with a few exceptions, significantly more pronounced in the intervention groups than in the corresponding control groups (comparison of percentage change from baseline). In particular, body weight was reduced by 7.4% (6.4 kg) and 7.5% (5.9 kg), low-density lipoprotein cholesterol concentrations by 19.8% (0.8 mmol/L) and 13.0% (0.5 mmol/L), TG concentrations by 18.2% (0.3 mmol/L) and 13.0% (0.2 mmol/L), and homeostatic model assessment for insulin resistance by 31.8% (1.1) and 26.4% (0.9) (p < 0.05) in the hypertriglyceridemia and prediabetes intervention groups, respectively. Some of these changes were maintained until follow-up. In patients with elevated TG or fasting glucose, implementing individualized menu plans in combination with regular counseling sessions over 10 weeks led to a significant improvement in cardiovascular and diabetic risk factors.

Moderate intake of BCAA-rich protein improves glucose homeostasis in high-fat-fed mice

Notwithstanding the fact that dietary branched-chain amino acids (BCAAs) have been considered to be a cause of insulin resistance (IR), evidence indicates that BCAA-rich whey proteins (WPs) do not lead to IR in animals consuming high-fat (HF) diets and may instead improve glucose homeostasis. To address the role of BCAA-rich WP as dietary protein in IR and inflammatory response, we fed C57BL/6J mice either high-fat (HF) or low-fat (LF) diets formulated with moderate protein levels (13% w/w) of either WP or hydrolyzed WP (WPH) and compared them with casein (CAS) as a reference. The muscle and plasma free amino acid profiles, inflammatory parameters and glycemic homeostasis were examined. While the LF/CAS diet promoted the rise in triglycerides and inflammatory parameters, the HF/CAS induced typical IR responses and impaired biochemical parameters. No differences in plasma BCAAs were detected, but the HF/WPH diet led to a twofold increase in gastrocnemius muscle free amino acids, including BCAAs. In general, ingestion of WPH was effective at averting or attenuating the damage caused by both the LF and HF diets. No high concentrations of BCAAs in the plasma or signs of IR were found in those mice fed an HF diet along with the hydrolyzed whey proteins. It is concluded that consumption of BCAA-rich whey proteins, especially WPH, does not result in the development of IR.

Impact of milk consumption on cardiometabolic risk in postmenopausal women with abdominal obesity

Background

The impact of dairy intake on cardiometabolic risk factors associated with metabolic syndrome (MetS) needs further research.

Objective

To investigate the impact of milk consumption on a wide array of cardiometabolic risk factors associated with MetS (blood lipids, cholesterol homeostasis, glucose homeostasis, systemic inflammation, blood pressure, endothelial function) in postmenopausal women with abdominal obesity.

Methods

In this randomized, crossover study, 27 women with abdominal obesity consumed two 6-week diets based on the National Cholesterol Education Program (NCEP), one with 3.2 servings/d of 2% fat milk per 2000 kcal (MILK) and one without milk or other dairy (NCEP). The macronutrient composition of both diets was comparable (55% carbohydrates, 15% proteins, 30% fat and 10% saturated fat).

Results

The MILK diet had no significant effect on LDL-C, triglycerides, LDL size, CRP and cell adhesion molecule concentrations and on indicators of insulin sensitivity. The MILK diet reduced HDL-C, adiponectin, endothelin and fasting glucose levels as well blood pressure (all P ≤ 0.01), but those changes were comparable to those seen with the NCEP milk-free diet (all between-diet P ≥ 0.07). Finally, the MILK diet was associated with lower VLDL apolipoprotein B fractional catabolic rate (−13.4%; P = 0.04) and plasma sterol concentrations (−12.0%; P = 0.04) compared with the control NCEP milk-free diet.

Conclusions

These data suggest that short-term consumption of low fat milk in the context of a prudent NCEP diet has no favorable nor deleterious effect on cardiometabolic risk factors associated with MetS in postmenopausal women with abdominal obesity.

Electronic supplementary material

The online version of this article (doi:10.1186/1475-2891-14-12) contains supplementary material, which is available to authorized users.

The impact of abdominal obesity status on cardiovascular response to the mediterranean diet

We investigated the impact of abdominal obesity status on the cardiovascular response to a fully controlled 4-week isoenergetic Mediterranean diet (MedDiet). Thirty-eight abdominally obese individuals (waist circumference >102 cm in men and >88 cm in women) and thirty-one nonabdominally obese individuals were recruited and studied before and after the MedDiet. All analyses were adjusted for the slight decrease in body weight, which occurred during the MedDiet (mean: 0.9 ± 1.2 kg). A group by time interaction was noted for waist circumference (P = 0.02), abdominally obese subjects showing a significant decrease and nonabdominally obese subjects a nonsignificant increase (resp., -1.1 and +0.3%). The MedDiet resulted in decreases in total cholesterol, LDL-C, HDL-C, apolipoprotein B, A-1, and A-2, total cholesterol/HDL-C ratio, LDL-C/HDL-C ratio, and systolic and diastolic blood pressure (time effect: P < 0.05). For all variables related to glucose/insulin homeostasis, no change was observed except for a decrease in 2 h glucose concentrations (time effect: P = 0.03). No group by time interaction was observed in any of the metabolic variables studied. Results from our study suggest that the adoption of the MedDiet leads to beneficial metabolic effects, irrespective of the abdominal obesity status.

Hypocaloric peripheral parenteral nutrition with lipid emulsion in postoperative gastrointestinal cancer patients

AIM: To investigate the use of lipid emulsion substituting for glucose in postoperative hypocaloric peripheral parenteral nutrition (HPPN).

METHODS: This prospective, randomized study was conducted on 20 postoperative gastrointestinal cancer patients. They were randomized and equally divided into interventional group and control group, and both were administered isocaloric and isonitrogenous diets with for lipid emulsion substituting for partial glucose loads in the interventional group.

RESULTS: Nutritional parameters and biochemical data were compared between the two groups before and after 6-d of HPPN. Most investigated variables showed no significant changes after administration of HPPN with lipid emulsion. However, the postoperative triglyceride level was significantly lower in the interventional group than in the control group (P < 0.05). In comparison with lipid emulsion, glucose administration resulted in less decrease in postoperative prealbumin level (P < 0.05).

CONCLUSION: In addition to supplementing with essential fatty acid, it seems that HPPN with lipid emulsion is well-tolerated and beneficial to postoperative gastrointestinal cancer patients.

Intravascular kinetics of C-reactive protein and their relationships with features of the metabolic syndrome

OBJECTIVE

The objective of the study was to describe, for the first time, the intravascular kinetics of C-reactive protein (CRP), using stable isotopes, and its relationship with features of the metabolic syndrome.

METHODS

Sixteen men and 16 women [aged 49 +/- 9 years, body mass index (BMI) 28.7 +/- 4.5 kg/m(2)] underwent a 12-h primed-constant infusion of 5,5,5-(2)H(3)-l-leucine. CRP was purified from the plasma fraction rho greater than 1.25 g/ml by affinity chromatography, and isotopic enrichment over time was determined by gas chromatography/mass spectrometry.

RESULTS

The CRP fractional catabolic rate was 60% higher in men than women (0.49 +/- 1.83 vs. 0.30 +/- 1.80 pool/d, P = 0.03), but this difference was no longer significant in a multivariate model that included several features associated with the metabolic syndrome. The CRP production rate (PR) and pool size were not statistically different between sexes. Plasma CRP concentrations were more strongly correlated with the PR (r = 0.80, P < 0.0001) than with the fractional catabolic rate of CRP (r = 0.39, P < 0.05). The PR of CRP was positively correlated with waist girth (r = 0.53, P < 0.01), plasma low-density lipoprotein apolipoprotein B-100 (r = 0.42, P = 0.07), triglyceride (r = 0.41, P = 0.06), and IL-6 concentrations (r = 0.61, P = 0.0008) and inversely correlated with high-density lipoprotein-cholesterol (r = -0.47, P = 0.03) and adiponectin (r = -0.63, P < 0.0005) after adjustment for sex. Blood pressure and low-density lipoprotein-cholesterol showed no association with CRP kinetics.

CONCLUSION

The PR of CRP appeared as the main determinant of CRP concentrations and showed significant associations with features of the metabolic syndrome as well as with adipose tissue-derived cytokines such as IL-6 and adiponectin.

A MUFA-rich diet improves posprandial glucose, lipid and GLP-1 responses in insulin-resistant subjects

OBJECTIVE

To study the effects of three weight-maintenance diets with different macronutrient composition on carbohydrate, lipid metabolism, insulin and incretin levels in insulin-resistant subjects.

METHODS

A prospective study was performed in eleven (7 W, 4 M) offspring of obese and type 2 diabetes patients. Subjects had a BMI > 25 Kg/m2, waist circumference (men/women) > 102/88, HBA1c < 6.5% and were regarded as insulin-resistant after an OGTT (Matsuda ISIm <4). They were randomly divided into three groups and underwent three dietary periods each of 28 days in a crossover design: a) diet high in saturated fat (SAT), b) diet rich in monounsaturated fat (MUFA; Mediterranean diet) and c) diet rich in carbohydrate (CHO).

RESULTS

Body weight and resting energy expenditure did not changed during the three dietary periods. Fasting serum glucose concentrations fell during MUFA-rich and CHO-rich diets compared with high-SAT diets (5.02 +/- 0.1, 5.03 +/- 0.1, 5.50 +/- 0.2 mmol/L, respectively. Anova < 0.05). The MUFA-rich diet improved insulin sensitivity, as indicated by lower homeostasis model analysis-insulin resistance (HOMA-ir), compared with CHO-rich and high-SAT diets (2.32 +/- 0.3, 2.52 +/- 0.4, 2.72 +/- 0.4, respectively, Anova < 0.01). After a MUFA-rich and high-SAT breakfasts (443 kcal) the postprandial integrated area under curve (AUC) of glucose and insulin were lowered compared with isocaloric CHO-rich breakfast (7.8 +/- 1.3, 5.84 +/- 1.2, 11.9 +/- 2.7 mmol . 180 min/L, Anova < 0.05; and 1004 +/- 147, 1253 +/- 140, 2667 +/- 329 pmol . 180 min/L, Anova <0.01, respectively); while the integrated glucagon-like peptide-1 response increased with MUFA and SAT breakfasts compared with isocaloric CHO-rich meals (4.22 +/- 0.7, 4.34 +/- 1.1, 1.85 +/- 1.1, respectively, Anova < 0.05). Fasting and postprandial HDL cholesterol concentrations rose with MUFA-rich diets, and the AUCs of triacylglycerol fell with the CHO-rich diet. Similarly fasting proinsulin (PI) concentration fell, while stimulated ratio PI/I was not changed by MUFA-rich diet.

CONCLUSIONS

Weight maintenance with a MUFA-rich diet improves HOMA-ir and fasting proinsulin levels in insulin-resistant subjects. Ingestion of a virgin olive oil-based breakfast decreased postprandial glucose and insulin concentrations, and increased HDL-C and GLP-1 concentrations as compared with CHO-rich diet.

Kinetics of plasma apolipoprotein C-III as a determinant of diet-induced changes in plasma triglyceride levels

OBJECTIVE

To compare the effect of a high monounsaturated fatty acid (MUFA) diet and of a control low-fat diet consumed under ad libitum conditions on plasma apolipoprotein (apo) C-III metabolism.

DESIGN

Randomized, two-arm parallel dietary trial.

SETTING

Diets were prepared and consumed at the metabolic kitchen of the Department of Food Sciences and Nutrition, and laboratory analyses were performed at the Institute of Nutraceuticals and Functional Foods at Laval University.

SUBJECTS AND INTERVENTIONS

Eighteen men were randomly assigned to either the high MUFA diet or the low-fat control diet, which they consumed for 6-7 weeks. Before and after the dietary intervention, subjects received a primed-constant infusion of [5,5,5-D(3)]-L-leucine for 12 h under constant feeding conditions for the determination of plasma apoC-III kinetics.

RESULTS

The high-MUFA diet and the low-fat control diet had no significant impact on plasma apoC-III production rate (PR) or fractional catabolic rate. However, diet-induced variations in plasma apoCIII PR predicted the reduction in plasma triglycerides and apoC-III levels (r=0.85, P<0.01 and r=0.73, P<0.05, respectively) in the high MUFA group only.

CONCLUSIONS

These results suggest that the hypotriglyceridemic effect of a high-MUFA diet may be attributable in part to a reduced hepatic production of apoC-III.

SPONSORSHIP

This study was supported in part by an operating grant from the Canadian Institutes of Health Research (CIHR), and the Canada Research Chair in Nutrition and Cardiovascular Health (B Lamarche).

Effect of a nutritional intervention promoting the Mediterranean food pattern on anthropometric profile in healthy women from the Québec city metropolitan area

OBJECTIVE

To evaluate the impact of a nutritional intervention promoting a Mediterranean food pattern on anthropometric profile in healthy women.

DESIGN

Nutritional intervention study.

SETTING

Laval University, Canada.

SUBJECTS

Seventy-seven healthy women started the study and four did not complete the study.

METHODS

A 12-week nutritional intervention in free-living conditions consisted of two group courses on nutrition and seven individual sessions with a dietitian. A follow-up visit was performed 12 weeks after the end of the intervention (week 24). A Mediterranean dietary score (MedScore), based on the 11 components of the Mediterranean pyramid, was established to evaluate the adherence to the Mediterranean food pattern.

RESULTS

Small but significant decreases in body weight and waist circumference were observed after 12 weeks of intervention (0.5 kg and 1.2 cm, respectively (P<0.01)). Increase in partial MedScore for legumes, nuts and seeds (increase in consumption) as well as increase in partial MedScore for sweets (decrease in consumption) were significantly associated with changes in waist circumference (r=-0.36, P=0.001; r=0.24, P=0.05, respectively). No association was observed between changes in anthropometric profile and changes in the consumption of olive oil.

CONCLUSION

Changes in dietary food pattern, more specifically an increase in the consumption of legumes, nuts and seeds, and a decrease in the consumption of sweets, were associated with some beneficial changes in anthropometric profile.

Visceral adiposity and endothelial lipase

CONTEXT

Overexpression of endothelial lipase (EL) has been shown to reduce plasma high-density lipoprotein cholesterol levels in animal models. However, the extent to which EL contributes to modulate the deteriorated high-density lipoprotein profile observed in obesity in humans is less clear.

OBJECTIVES

The objectives of this study were to investigate the association between levels of obesity and visceral adiposity in particular and plasma EL concentrations.

METHODS

Postheparin plasma EL concentrations were measured by ELISA and visceral adiposity by computed tomography in a sample of 80 sedentary men in good health. EL mRNA levels in abdominal sc and omental adipose tissues obtained during abdominal hysterectomies were measured in another sample of 14 women.

RESULTS

Plasma EL levels were positively correlated with body mass index (R = 0.46, P < 0.0001), visceral adipose tissue accumulation (R = 0.44, P < 0.0001), and a proatherogenic lipid profile including increased plasma cholesterol and triglycerides. However, EL mRNA levels were similar in sc and omental AT and were 10,000-fold lower than lipoprotein lipase mRNA levels in those tissues.

CONCLUSIONS

Increased visceral adiposity is significantly correlated with elevated plasma EL levels, but this association is unlikely to be causal and may reflect other common metabolic alterations.

Apolipoprotein C-III isoforms: kinetics and relative implication in lipid metabolism

Apolipoprotein C-III (apoC-III) production rate (PR) is strongly correlated with plasma triglyceride (TG) levels. ApoC-III exists in three different isoforms, according to the sialylation degree of the protein. We investigated the kinetics and respective role of each apoC-III isoform in modulating intravascular lipid/lipoprotein metabolism. ApoC-III kinetics were measured in a sample of 18 healthy men [mean age (+/-SD) 42.1 +/- 9.5 years, body mass index 29.8 +/- 4.6 kg/m2] using a primed-constant infusion of l-(5,5,5-D3) leucine for 12 h. Mono-sialylated and di-sialylated apoC-III (apo-CIII1 and apoC-III2) exhibited similar PRs (means +/- SD, 1.22 +/- 0.49 mg/kg/day vs. 1.15 +/- 0.59 mg/kg/day, respectively) and similar fractional catabolic rates (FCRs) (0.51 +/- 0.13 pool/day vs. 0.61 +/- 0.24 pool/day, respectively). Nonsialylated apoC-III (apoC-III0) had an 80% lower PR (0.25 +/- 0.12 mg/kg/day) and a 60% lower FCR (0.21 +/- 0.07 pool/day) (P < 0.0001 for comparison with CIII1 and CIII2 isoforms). The PRs of apoC-III1 and apoC-III2 were more strongly correlated with plasma TG levels (r > 0.8, P < 0.0001) than was apoC-III0 PR (r = 0.54, P < 0.05). Finally, the PR of apoC-III2 was strongly correlated with the proportion of LDL <255 A (r = 0.72, P = 0.002). These results suggest that all apoC-III isoforms, especially the predominant CIII1 and CIII2 isoforms, contribute to hypertriglyceridemia and that apoC-III2 may play a significant role in the expression of the small, dense LDL phenotype.

Treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause for elevated liver enzymes in the developed nations. Beyond prevention programs which are of particular interest because of the increasing number of overweight children, treatment should be focussed on the most important risk factors, obesity and insulin resistance. As a consequence of elucidating the pathomechanisms of NAFLD, the number of potential therapeutic options increased. However, many studies investigating the therapeutic effect show shortcomings in at least one of the following points: lack of a serial liver biopsy, short term of treatment and limited number of included patients. The second generation insulin sensitizer pioglitazone and rosiglitazone show the most promising improvements in NAFLD, but weight gain and potential hepatotoxicity calls for attention. In conclusion, a general recommendation for the application of specific drugs cannot be given. Besides controlled clinical trials, weight reduction and physical activity to improve insulin sensitivity in obese patients should be the priority objective.

Baseline plasma C-reactive protein concentrations influence lipid and lipoprotein responses to low-fat and high monounsaturated fatty acid diets in healthy men

To date, no studies have compared the effects of consuming a low-fat diet and a high monounsaturated fatty acid (MUFA) diet, under unrestricted energy intake conditions, on plasma C-reactive protein (CRP) concentrations. Men [n = 61; 37.5 +/- 11.5 y old (mean +/- SD), mean BMI 29.0 +/- 5.0 kg/m2] were randomly assigned to consume ad libitum a moderately low-fat diet (25.8% of energy intake from fat) or a high-fat diet rich in MUFA (40.1% of energy intake from fat, 22.5% from MUFA) for 6-7 wk. Plasma CRP concentrations were measured using a highly sensitive assay. Neither diet affected the plasma CRP concentration. However, baseline CRP concentrations predicted lipoprotein/lipid responsiveness to the experimental diets. After intake of the low-fat diet, plasma total and VLDL-triglyceride (TG) concentrations were increased in the subgroup with high CRP concentrations (P < 0.05 and P < 0.01, respectively) whereas they were reduced in the subgroup with low CRP concentrations at baseline (P < 0.01 for both). The high-MUFA diet reduced plasma TG, VLDL-TG, and VLDL cholesterol only in the subgroup with low CRP at baseline (P < 0.0001). In conclusion, the low-fat diet and the high-MUFA diet did not affect plasma CRP concentrations. However, baseline plasma CRP concentrations may modulate the diet-induced changes in plasma lipid and lipoprotein concentrations.

Visceral adipose tissue accumulation, secretory phospholipase A2-IIA and atherogenecity of LDL

OBJECTIVE

The aim of the present study was to investigate the combined impact of visceral adipose tissue (VAT) and secretory group IIA phospholipase A(2) (sPLA(2)-IIA) concentrations on the atherogenicity of low-density lipoprotein (LDL) particles among men.

SUBJECTS

Analyses were conducted in 74 mid-obese healthy men (age: (mean+/-s.d.) 37.9+/-11.7 years).

METHODS

Plasma levels of sPLA(2)-IIA were measured with a commercial ELISA and VAT levels were assessed by computed tomography. Distinct subpopulations of LDL particles were characterized from whole plasma using nondenaturating 2-16% gradient gel electrophoresis.

RESULTS

Data indicated that plasma sPLA(2)-IIA levels were approximately 29% (P=0.007) higher among men characterized by a higher accumulation of VAT (>142 vs < or =142 cm(2)). Men having high plasma sPLA(2)-IIA levels (> or =127.2 ng/dl, the median value), were characterized by higher levels of plasma cholesterol (C) and apolipoprotein (apo) B, LDL-C, LDL-apoB, oxidized LDL (OxLDL) and by smaller LDL particles compared to men with sPLA(2)-IIA<127.2 ng/dl. Multiple regression analyses showed that plasma triglycerides and sPLA(2)-IIA levels explained 22.7 and 11.8% of the variance in LDL peak particle size, respectively. Levels of VAT and of sPLA(2)-IIA were the strongest correlates of OxLDL levels explaining, respectively, 15.0 and 5.5% of their variability.

CONCLUSION

Both VAT and sPLA(2)-IIA levels modulate the atherogenecity of LDL by accounting for the reduction in their size and their susceptibility to oxidation.

Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1

BACKGROUND

It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone.

OBJECTIVE

The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction.

DESIGN

English-language studies with a dietary intervention of > or =4200 kJ/d (1000 kcal/d), with a duration of > or =4 wk, and conducted in subjects aged > or =19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria.

RESULTS

After control for energy intake, diets consisting of < or =35-41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes < or =1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed.

CONCLUSION

Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.

Low- and high-carbohydrate diets: body composition differences in rats

OBJECTIVE

To determine differences in adipose tissue mass, cell size, and lipid metabolism transcripts and differences in composition of body weight loss and energy expenditure (EE) after isoenergetic, energy-restricted intake of low-carbohydrate/high-fat/high-protein (LC) and high-carbohydrate/low-fat/moderate-protein (HC) diets.

RESEARCH METHODS AND PROCEDURES

Ten-week old female Sprague-Dawley rats were fed a high-fat diet ad libitum for 8 weeks to induce weight gain and fat deposition. Weight-matched rats were then assigned to isoenergetic LC (Atkins) and HC (American Dietary Association Exchange) diets for 10 weeks at 65% of ad libitum energy intake.

RESULTS

There was no significant difference in the serum lipid profiles or amount of body weight lost between the HC and LC groups, whereas a higher insulin sensitivity index (p < 0.01) resulted from the HC compared with the LC diet. Compared with the post-restriction LC group, the HC group demonstrated (p < 0.05) higher EE during active hours, lower mRNA levels for the lipogenic genes peroxisome proliferator-activated receptor gamma2, lipoprotein lipase, and, adipocyte fatty acid binding protein, decreased adipocyte cell volume, and decreased fat mass.

DISCUSSION

Results indicated down-regulation of lipogenic genes, decreased fat mass, and, therefore, improved body composition in the post-restriction HC compared with the LC group. The small mean differences between the two diet groups (p = 0.11) in 24-hour EE over the 10 weeks of diet intervention would account for the majority of the lower mean body weights in the post-restriction HC group. These data suggest that macronutrient composition of the diet influences body composition and indicate a distinction between HC and LC diets.

Evaluation of epidemiologic evidence on the role of nutrition in the development of diabetes and its complications

This article evaluates the body of epidemiologic evidence on the effects of nutritional factors in diabetes development published within the past 5 years (2000-2004), considering strengths and weaknesses of specific studies, as well as of various study designs in general. Furthermore, this article aims to determine whether clinical practice and public health practice guidelines should, or should not, be determined based on the totality of available scientific evidence.

Variations in plasma apolipoprotein C-III levels are strong correlates of the triglyceride response to a high-monounsaturated fatty acid diet and a high-carbohydrate diet

The objective of this study was to examine how a diet rich in carbohydrates (high-CHO) vs a diet rich in monounsaturated fatty acids (high MUFA) consumed ad libitum modulated plasma apolipoprotein C-III (apo C-III) levels and to examine the extent to which diet-induced changes in plasma apo C-III were associated with concurrent variations in plasma triglyceride (TG) levels. Forty-seven men (mean age, 35.7 +/- 11.4 years; body mass index, 29.0 +/- 5.1 kg/m2) were randomly assigned to either a high-CHO diet (CHO, 58%; fat, 26%; n = 23) or a high-MUFA diet (CHO, 45%; fat, 40%; MUFA, 22.5%; n = 24), which they consumed for 6 to 7 weeks. Fasting and postprandial lipemia after an oral fat load and fasting plasma apo C-III were measured at the beginning and at the end of the dietary intervention. Ad libitum consumption of the high-CHO diet induced a significant reduction in body weight (-2.6%, P < .0001), but had no impact on plasma apo C-III concentrations and on fasting and postprandial plasma TG levels. In contrast, ad libitum consumption of the high-MUFA diet also resulted in a significant reduction in body weight (-2.3%, P < .01) as well as in significant reductions in plasma apo C-III (-11%, P = .05) and fasting plasma TG (-17%, P < .01). Diet-induced variations in plasma apo C-III concentrations were correlated with changes in fasting and postprandial TG levels both in the high-CHO (r > 0.70, P < .001) and the high-MUFA groups (r > 0.42, P < .05). These results indicate that variations in plasma apo C-III levels are strong correlates of the fasting and postprandial plasma TG responses to high-MUFA and high-CHO diets.

Combination diet and exercise interventions for the treatment of dyslipidemia: an effective preliminary strategy to lower cholesterol levels?

At present, dyslipidemia is most commonly treated with drug therapy. However, because safety concerns regarding the use of pharmaceutical agents have arisen, a need for alternative nonpharmacological therapies has become increasingly apparent. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) recommends lifestyle therapies, which include a combination of diet and exercise modifications, in place of drug treatment for patients who fall into an intermediate range of coronary heart disease (CHD) risk. This review examined the cholesterol lowering efficacy of the following 2 NCEP-recommended combination therapies: 1) low saturated fat diets combined with exercise, and 2) nutritional supplementation, i.e., fish oil, oat bran, or plant sterol supplementation, combined with exercise, in the treatment of dyslipidemia. Combination therapies are particularly advantageous because diet and exercise elicit complementary effects on lipid profiles. More specifically, diet therapies, with some exceptions, lower total (TC) and LDL cholesterol (LDL-C) concentrations, whereas exercise interventions increase HDL cholesterol (HDL-C) while decreasing triglyceride (TG) levels. With respect to specific interventions, low saturated fat diets combined with exercise lowered TC, LDL-C, and TG concentrations by 7-18, 7-15, and 4-18%, respectively, while increasing HDL-C levels by 5-14%. Alternatively, nutritional supplements combined with exercise, decreased TC, LDL-C, and TG concentrations by 8-26, 8-30, and 12-39%, respectively, while increasing HDL-C levels by 2-8%. These findings suggest that combination lifestyle therapies are an efficacious, preliminary means of improving cholesterol levels in those diagnosed with dyslipidemia, and should be implemented in place of drug therapy when cholesterol levels fall just above the normal range.

Apolipoprotein A-I, A-II, and VLDL-B-100 metabolism in men

The impact of a low-fat diet and a high-MUFA diet on apolipoprotein A-I (apoA-I), apoA-II, and VLDL-apoB-100 metabolism in conditions of unrestricted (ad libitum) energy intake was compared in 65 men randomly assigned to one of two predefined experimental diets. A subsample of 18 men participated in the kinetic study. Before and after the 6-7 week dietary intervention, kinetic subjects received a primed-constant infusion of [5,5,5-2H3]L-leucine for 12 h under feeding conditions. ApoA-I production rate (PR; -31.5%; P <0.001) and fractional catabolic rate (FCR; -24.3%; P <0.05) were significantly decreased after the low-fat diet. These changes in apoA-I PR and FCR with the low-fat diet were also significantly different from those observed with the high-MUFA diet (P <0.01 and P <0.05, respectively). ApoA-II FCR was significantly increased in the high-MUFA group only. No significant within- or between-diet difference was found in VLDL-apoB-100 PR or FCR. These results emphasize the differential impact of the low-fat diet and high-MUFA diet on HDL metabolism.

Very low-fat (12%) and high monounsaturated fat (35%) diets do not differentially affect abdominal fat loss in overweight, nondiabetic women

Studies in women with type 2 diabetes demonstrated adverse effects on body fat distribution of a low-fat diet relative to a high monounsaturated fat diet. We performed a randomized 12-wk parallel design study of two 6000-kJ diets: 35% energy from fat (high monounsaturated fat diet, HIMO), or 12% energy from fat (very low-fat diet, VLF) to determine whether this also occurred in nondiabetic women. Body fat distribution, fasting plasma glucose, blood pressure, and fasting serum lipids were measured at wk 0 and 12 in 62 women (BMI > 27 kg/m(2)). Weight loss (9.5 +/- 2.4 vs. 9.4 +/- 3.4 kg, VLF vs. HIMO) and total fat loss (6.1 +/- 2.4 vs. 6.3 +/- 2.7 kg, VLF vs. HIMO) did not differ in the groups. There was a diet x menopausal status interaction in lean mass changes (P = 0.005) such that in premenopausal women, HIMO produced a lower loss of lean mass than the low-fat diet (0.4 +/- 2.3 vs. 2.9 +/- 2.7 kg, P = 0.006) with the opposite but nonsignificant effect seen in postmenopausal women. There was a greater decrease in total plasma cholesterol in women who consumed VLF compared with those who consumed HIMO (0.82 +/- 0.0.51 vs. 0.50 +/- 0.48 mmol/L, P < 0.001 for time, P < 0.05 for diet effect). This was also true for the change in HDL cholesterol (0.18 +/- 0.23 vs. 0.04 +/- 0.19 mmol/L, VLF and HIMO, respectively, P < 0.001 for time, P < 0.05 for diet effect). The LDL/HDL ratio was reduced in both groups with no effect of diet (0.16 +/- 0.51 vs. 0.16 +/- 0.45, VLF and HIMO, respectively, P < 0.05). In conclusion, weight, total fat mass, and regional fat mass loss did not differ in the 2 groups of women but there was an apparent preservation of lean mass in premenopausal women consuming HIMO.