A reduction of 3 g/day from a usual 9 g/day salt diet improves endothelial function and decreases endothelin-1 in a randomised cross_over study in normotensive overweight and obese subjects

BACKGROUND AND AIM

It is unclear if a modest reduction in dietary salt intake has beneficial effects on vascular function. The aim was to compare the effects of 9 g salt/day with 6 g salt/day intake on measures of vascular function and explore mechanisms of effect in overweight and obese adults.

METHODS

Twenty-five overweight/obese subjects (BMI 27-40 kg/m(2)) completed a randomised cross-over study of 6 weeks each on a reduced salt (RS) (6 g/day) and usual salt diet (US) (9 g/day). Flow-mediated-dilatation (FMD), 24 h blood pressure (BP), augmentation index (AIx), pulse wave velocity (PWV), plasma and urinary nitrate/nitrite, asymmetric dimethylarginine (ADMA), renin, aldosterone and endothelin-1 and vascular adhesion molecules were measured after 2 days and 6 weeks. Adherence to the diets was determined from two 24 h urine collections.

RESULTS

Urinary sodium excretion was 155 ± 58 mmol/24 h US vs 113 ± 45 mmol/24 h RS (p = 0.002). Following the RS diet there was a significant improvement in FMD from 3.5 ± 2.8% to 5.6 ± 2.8% (P < 0.001) and decrease in serum endothelin-1 from 1.45 ± 0.38 pg/ml to 1.25 ± 0.39 pg/ml (P < 0.05). Endothelium-independent vasodilatation was also significantly different between treatments (P < 0.05). AIx, PWV, serum ADMA and plasma and urinary nitrate/nitrite concentrations were not different between treatments. Change in FMD was related to the urinary sodium: creatinine ratio (r = -0.47, P < 0.05) and was independent of blood pressure. Aldosterone and renin were unchanged.

CONCLUSIONS

A small reduction in dietary salt intake of 3 g/day improves endothelial function in normotensive overweight and obese subjects. This response may be mediated by serum endothelin-1. This small reduction in salt had no effect on aldosterone and renin concentrations. This trial was registered with the Australian and New Zealand Clinical Trials Registry Unique Identifier: ACTRN12609000321246 http://www.anzctr.org.au/ACTRN12609000321246.aspx.

Postprandial effects of a high salt meal on serum sodium, arterial stiffness, markers of nitric oxide production and markers of endothelial function

AIM

The aim of the study was to determine if a high salt meal containing 65 mmol Na causes a rise in sodium concentrations and a reduction in plasma nitrate/nitrite concentrations (an index of nitric oxide production). Secondary aims were to determine the effects of a high salt meal on augmentation index (AIx) a measure of arterial stiffness and markers of endothelial function.

METHODS AND RESULTS

In a randomised cross-over study 16 healthy normotensive adults consumed a low sodium soup containing 5 mmol Na and a high sodium soup containing 65 mmol Na. Sodium, plasma nitrate/nitrite, endothelin-1 (ET-1), C-reactive protein (CRP), vasopressin (AVP) and atrial natriuretic peptide (ANP) concentrations before and every 30 min after the soup for 2 h. Blood pressure (BP) and AI were also measured at these time points. There were significant increases in serum sodium, osmolality and chloride in response to the high sodium meal. However plasma nitrate/nitrite concentrations were not different between meals (meal p = 0.812; time p = 0.45; meal × time interaction p = 0.50). Plasma ANP, AVP and ET-1 were not different between meals. AI was significantly increased following the high sodium meal (p = 0.02) but there was no effect on BP.

CONCLUSIONS

A meal containing 65 mmol Na increases serum sodium and arterial stiffness but does not alter postprandial nitrate/nitrite concentration in healthy normotensive individuals. Further research is needed to explore the mechanism by which salt affects vascular function in the postprandial period. This trial was registered with the Australian and New Zealand Clinical Trials Registry Unique Identifier: ACTRN12611000583943http://www.anzctr.org.au/trial_view.aspx?ID=343019.

Remission of diabetes in patients with long-standing type 2 diabetes following placement of adjustable gastric band: a retrospective case control study

Rates of remission in obese patients with long-standing type 2 diabetes (>2 years), following an adjustable gastric band are unclear. We conducted a retrospective case-control study of patients (n = 89) matched for age and body mass index with non-surgical controls. Cases had a longer duration of diabetes (99 ± 53 and 80 ± 59 months, p < 0.05) and a lower HbA1c than controls (7.9 ± 1.6 vs. 8.5 ± 1.9%, p < 0.05). At follow-up (median 105 weeks) cases had lost 16.8 ± 13.5 kg and controls 1.7 ± 8.9 kg (p < 0.001) and HbA1c decreased by 0.6-0.8% (p < 0.001 for time) with no difference between cases and controls. Diabetes resolution, defined by HbA1c less than 6.5% and taking no medications, occurred in 14 (16%) cases and 2 controls. This is in contrast to published outcomes of resolution of type 2 diabetes after bariatric surgery. We conclude that there is a clear need for randomized studies of the effect of gastric banding in patients with long-standing type 2 diabetes.

Evaluation of the Swedish adjustable gastric band VC (SAGB-VC) in an Australian population: early results

BACKGROUND

The Swedish adjustable gastric band VC (SAGB-VC) has been in use in Australia since 2007. We evaluated its efficacy and safety.

METHODS

We retrospectively analyzed the prospective clinical data of patients who received the implant between November 2007 and June 2009 at 3 Australian bariatric centres.

RESULTS

In all, 1176 patients (mean age 45.9 [standard deviation (SD) 12.3] yr, mean body mass index 43.4 [SD 7.6]) received the SAGB-VC. At a mean follow-up of 11 (SD 3) months, weight reduced by a mean of 18.4 (SD 11.1) kg with an excess weight loss of 37.8% (SD 19.9%). Body mass index decreased (from mean 43.4 [SD 7.7] to mean 36.7 [SD 6.5], p < 0.001). Type 2 diabetes (T2DM) was reported in 167 patients and hypertension in 373. Improvement occurred in 73.5% of patients with T2DM and 31% with hypertension, with patient-reported reduction or cessation of medication. Metabolic syndrome indices improved during follow-up: high-density lipoprotein cholesterol (mean 1.3 [SD 0.3] v. mean 1.4 [SD 0.3] mmol/L, p < 0.001), triglycerides (mean 1.6 [SD 0.8] v. mean 1.3 [SD 0.7] mmol/L, p < 0.001), waist circumference (men 141 [SD 103] to 121 [SD 15] cm, women 117 [SD 14] to 105 [SD 14] cm, both p < 0.001), C-reactive protein (90.5 [SD 75.2] v. 53.3 [SD 61.9] nmol/L, p < 0.001). The complication rate was 4.2%.

CONCLUSION

The SAGB-VC is safe and effective for treating obesity and its comorbidities. The results are reproducible in separate Australian centres and consistent with published literature.

Increased thiamine intake may be required to maintain thiamine status during weight loss in patients with type 2 diabetes

During weight loss, erythrocyte thiamine pyrophosphate (TPP) decreased (221±52 to 195±39 nmol/L, P<0.05) on a diet with adequate thiamine (1.1 mg/day) but was unchanged (217±55 vs 218±52 nmol/L, NS) on a high thiamine diet (2.8 mg/day). Attention to thiamine status may be required in patients with diabetes after weight loss.

Adherence to a Mediterranean diet and Alzheimer's disease risk in an Australian population

The Mediterranean diet (MeDi), due to its correlation with a low morbidity and mortality for many chronic diseases, has been widely recognised as a healthy eating model. We aimed to investigate, in a cross-sectional study, the association between adherence to a MeDi and risk for Alzheimer's disease (AD) and mild cognitive impairment (MCI) in a large, elderly, Australian cohort. Subjects in the Australian Imaging, Biomarkers and Lifestyle Study of Ageing cohort (723 healthy controls (HC), 98 MCI and 149 AD participants) completed the Cancer Council of Victoria Food Frequency Questionnaire. Adherence to the MeDi (0- to 9-point scale with higher scores indicating higher adherence) was the main predictor of AD and MCI status in multinominal logistic regression models that were adjusted for cohort age, sex, country of birth, education, apolipoprotein E genotype, total caloric intake, current smoking status, body mass index, history of diabetes, hypertension, angina, heart attack and stroke. There was a significant difference in adherence to the MeDi between HC and AD subjects (P < 0.001), and in adherence between HC and MCI subjects (P < 0.05). MeDi is associated with change in Mini-Mental State Examination score over an 18-month time period (P < 0.05) in HCs. We conclude that in this Australian cohort, AD and MCI participants had a lower adherence to the MeDi than HC participants.

Slowly and rapidly digested fat emulsions are equally satiating but their triglycerides are differentially absorbed and metabolized in humans

Little is known about the effect of dietary fat emulsion microstructure on plasma TG concentrations, satiety hormones, and food intake. The aim of this study was to structure dietary fat to slow digestion and flatten postprandial plasma TG concentrations but not increase food intake. Emulsions were stabilized by egg lecithin (control), sodium sterol lactylate, or sodium caseinate/monoglyceride (CasMag) with either liquid oil or a liquid oil/solid fat mixture. In a randomized, double-blind, crossover design, 4 emulsions containing 30 g of fat in a 350-mL preload were consumed by 10 men and 10 women (BMI = 25.1 ± 2.8 kg/m(2); age = 58.8 ± 4.8 y). Pre- and postprandial plasma TG, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) concentrations and food intake were measured. In a second experiment in a subset of the participants (n = 8, 4 men and 4 women), (13)C-labeled mixed TG was incorporated into 2 different emulsions and breath (13)C was measured over 6 h. In the first experiment, the postprandial rise in plasma TG concentrations following the CasMag-stabilized emulsion containing 30% solid fat was lower than all other emulsions at 90 and 120 min (P < 0.05). Plasma CCK (P < 0.0001), GLP-1 (P < 0.01), and PYY (P < 0.001) concentrations were also reduced following this emulsion compared with control. Food intake at a test meal, eaten 3 h after the preload, did not differ among the emulsions. In the second experiment, when measured by the (13)C breath test, 25% of the TG in the CasMag emulsion was absorbed and metabolized compared with control. In conclusion, fat can be structured to decrease its effect on plasma TG concentrations without increasing food intake.

Fecal butyrate levels vary widely among individuals but are usually increased by a diet high in resistant starch

Butyrate and other SCFA produced by bacterial fermentation of resistant starch (RS) or nonstarch polysaccharides (NSP) promote human colonic health. To examine variation in fecal variables, especially butyrate, among individuals and the response to these fibers, a randomized cross-over study was conducted that compared the effects of foods supplying 25 g of NSP or 25 g of NSP plus 22 g of RS/d over 4 wk in 46 healthy adults (16 males, 30 females; age 31-66 y). Fecal SCFA levels varied widely among participants at entry (butyrate concentrations: 3.5-32.6 mmol/kg; butyrate excretions: 0.3-18.2 mmol/48 h). BMI explained 27% of inter-individual butyrate variation, whereas protein, starch, carbohydrate, fiber, and fat intake explained up to 16, 6, 2, 4, and 2% of butyrate variation, respectively. Overall, acetate, butyrate, and total SCFA concentrations were higher when participants consumed RS compared with entry and NSP diets, but individual responses varied. Individual and total fecal SCFA excretion, weight, and moisture were higher than those for habitual diets when either fiber diet was consumed. SCFA concentrations (except butyrate) and excretions were higher for males than for females. Butyrate levels increased in response to RS in most individuals but often decreased when entry levels were high. Fecal butyrate and ammonia excretions were positively associated ((2) = 0.76; P < 0.001). In conclusion, fecal butyrate levels vary widely among individuals but consuming a diet high in RS usually increases levels and may help maintain colorectal health.

Endothelial function is impaired after a high-salt meal in healthy subjects

BACKGROUND

Dietary salt is related to blood pressure (BP), and cardiovascular disease and increased sodium intakes have been shown to impair vascular function. The effect of salt on endothelial function postprandially is unknown.

OBJECTIVE

The aim was to investigate the postprandial effect of dietary salt on endothelial function as measured by flow-mediated dilatation (FMD) and peripheral arterial tonometry in healthy subjects.

DESIGN

Sixteen healthy, normotensive subjects received a meal with added salt (HSM; 65 mmol Na) and a control low-salt meal (LSM; 5 mmol Na) on 2 separate occasions in a randomized order. Endothelial function was measured while fasting and postprandially at 30, 60, 90, and 120 min by using FMD and reactive hyperemia peripheral arterial tonometry. BP was also measured.

RESULTS

Baseline FMD, reactive hyperemia index (RHI), and BP values were similar across interventions. Overall FMD was reduced 2 h postprandially. FMD was significantly more impaired after the HSM than after the LSM at 30 min [HSM (mean ± SD): 3.39 ± 2.44%; LSM: 6.05 ± 3.21%; P < 0.01] and at 60 min (HSM: 2.20 ± 2.77%; LSM: 4.64 ± 2.48%; P < 0.01). No significant differences in BP or RHI were observed between meals.

CONCLUSIONS

An HSM, which reflects the typical amount of salt consumed in a commonly eaten meal, can significantly suppress brachial artery FMD within 30 min. These results suggest that high salt intakes have acute adverse effects on vascular dilatation in the postprandial state. This trial was registered at www.anzctr.org.au/trial_view.aspx?ID=335115 as ACTRN12610000124033.

A pilot comprehensive lifestyle intervention program (CLIP)--comparison with qualitative lifestyle advice and simvastatin on cardiovascular risk factors in overweight hypercholesterolaemic individuals

BACKGROUND AND AIMS

Escalating costs of pharmaceuticals for cardiovascular management highlight the need to develop effective lifestyle intervention programs to reduce reliance on these agents. The aim of this pilot study was to evaluate the efficacy of a Comprehensive Lifestyle Intervention Program (CLIP) compared with qualitative lifestyle advice (L) and Simvastatin plus qualitative lifestyle (S+L) on cardiovascular risk factors.

METHODS AND RESULTS

Sixty-five overweight adults with hypercholesterolemia were randomised to either L (qualitative advice on diet, exercise), S+L (20 mg/day Simvastatin plus L) or CLIP (6500 kJ structured menu plan: conventional and functional foods contributing <10% energy from saturated fat, ≥3 g soluble fibre, 2.4 g plant sterols, oily fish ≥2 times/week at lunch and dinner, plus exercise advice and self monitoring) for 6 weeks. LDL-cholesterol was lowered in CLIP (-0.57±0.67 mmol/L, 15%) and S+L (-1.43±0.59 mmol/L, 37%), but did not change significantly in L (-0.17±0.59, 4%) (P<0.001 time-by-treatment interaction). Weight and waist circumference were significantly lowered by CLIP (-4.2±2.2 kg; -5.1±2.3 cm) compared to L (-1.0±1.6 kg; -2.7±3.3 cm) and L+S (-0.7±1.4 kg; -2.4±2.3 cm), (P≤0.003 time-by-treatment interactions). B-carotene levels within treatment groups did not change over time and were not lowered by the CLIP diet compared to L (P>0.05, all). Blood pressure changes were not different between groups.

CONCLUSIONS

The structured CLIP program was more effective than qualitative lifestyle advice in improving weight, waist circumference and LDL-cholesterol without adverse effects on plasma carotenoids over a 6 week period. This program may therefore assist in comprehensive risk factor management, although the sustainability of these benefits needs confirmation.

Timing of protein ingestion relative to resistance exercise training does not influence body composition, energy expenditure, glycaemic control or cardiometabolic risk factors in a hypocaloric, high protein diet in patients with type 2 diabetes

AIM

To investigate timing of protein ingestion relative to resistance exercise training (RT) on body composition, cardiometabolic risk factors, glycaemic control and resting energy expenditure (REE) during weight loss on a high-protein (HP) diet in overweight and obese patients with type 2 diabetes (T2DM).

METHODS

Thirty-four men/women with T2DM (age 57 ± 7 years and body mass index 34.9 ± 4.2 kg m(-2) ) were randomly assigned to the ingestion of a HP meal (860 kJ, 21 g protein, 0.7 g fat, 29.6 g carbohydrate) either immediately prior to RT or at least 2 h following RT. All participants followed a 16-week, energy-restricted (6-7 MJ day(-1) ), HP diet (carbohydrate : protein : fat 43 : 33 : 22) and participated in supervised RT (3 day week(-1) ). Outcomes were assessed pre- and postintervention at 16 weeks.

RESULTS

There was an overall reduction in bodyweight (-11.9 ± 6.1 kg), fat mass (-10.0 ± 4.4 kg), fat-free mass (-1.9 ± 3.1 kg), waist circumference (-12.1 ± 5.3 cm), REE (-742 ± 624 kJ day(-1) ), glucose (-1.9 ± 1.7 mmol l(-1) ), insulin (-6.1 ± 6.7 mU l(-1) ) and glycosylated haemoglobin (-1.1 ± 0.1%), p ≤ 0.01 time for all variables, with no difference between groups (p ≥ 0.41 group effect). Strength improved and cardiometabolic risk factors were reduced similarly in both groups; single repetition maximum chest press 11.0 ± 8.7 kg, single repetition maximum lat pull down 9.9 ± 6.0 kg, total cholesterol -0.6 ± 0.5 mmol l(-1) , high-density lipoprotein cholesterol -0.1 ± 0.2 mmol l(-1) , low-density lipoprotein cholesterol -0.3 ± 0.5 mmol l(-1) , triglycerides -0.6 ± 0.7 mmol l(-1) , blood pressure (systolic/diastolic) -13 ± 10/-7 ± 7 mmHg (p ≤ 0.04 time effect, p ≥ 0.24 group effect).

CONCLUSION

A HP, energy-restricted diet with RT was effective in improving glycaemic control, body composition, strength and cardiometabolic risk factors in overweight/obese patients with T2DM irrespective of altering the timing of protein ingestion relative to RT.

Long-term effects of a low carbohydrate, low fat or high unsaturated fat diet compared to a no-intervention control

BACKGROUND AND AIM

Very low carbohydrate ad libitum diets have been shown to enhance weight loss without increasing cardiometabolic risk factors but no kilojoule-controlled trials have been conducted relative to no intervention. The aim of this study was to compare the changes in weight and other cardiovascular risk factors in 3 isocaloric energy-restricted diets to no-intervention control after 1 year.

METHODS AND RESULTS

One hundred and thirteen subjects (age 47 ± 10 years, BMI 32 ± 6 kg/m(2) with one additional cardiovascular risk factor) were randomly allocated to one of three isocaloric diets (VLC-very low carbohydrate, 60% fat, 4% carbohydrate, n=30; VLF-very low fat, 10% fat, n = 30; HUF-high unsaturated fat, 30% fat, n = 30) with intensive support for 3 months followed by minimal support for 12 months compared to a control group (no intervention, n = 23). The estimated weight change was -3.0 ± 0.2 kg for VLC, -2.0 ± 0.1 kg for VLF, -3.7 ± 0.01 kg for HUF and 0.8 ± 0.5 kg for controls (P=0.065). After correcting for baseline values, decreases in body weight and diastolic blood pressure in the diet groups (-2.9 ± 5.2) were significantly different to the increase in the control group (0.8 ± 5.0) (P<0.05). No differences in cardiovascular risk factors were observed between the diet groups.

CONCLUSION

Significant cardiometabolic risk factor reduction was observed equally with VLC, VLF and HUF diets after 15 months, compared to an exacerbation of risk factors in the control group. At a modest level of adherence, 3 months of intensive support on these dietary patterns confer an improvement in cardiometabolic profile compared to no dietary intervention after 15 months.

A high-protein diet with resistance exercise training improves weight loss and body composition in overweight and obese patients with type 2 diabetes

OBJECTIVE To evaluate the effects of two low-fat hypocaloric diets differing in the carbohydrate-to-protein ratio, with and without resistance exercise training (RT), on weight loss, body composition, and cardiovascular disease (CVD) risk outcomes in overweight/obese patients with type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 83 men and women with type 2 diabetes (aged 56.1 +/- 7.5 years, BMI 35.4 +/- 4.6 kg/m(2)) were randomly assigned to an isocaloric, energy-restricted diet (female subjects 6 MJ/day, male subjects 7 MJ/day) of either standard carbohydrate (CON; carbohydrate:protein:fat 53:19:26) or high protein (HP; 43:33:22), with or without supervised RT (3 days/week) for 16 weeks. Body weight and composition, waist circumference (WC), and cardiometabolic risk markers were assessed. RESULTS Fifty-nine participants completed the study. There was a significant group effect (P <or= 0.04) for body weight, fat mass, and WC with the greatest reductions occurring in HP+RT (weight [CON: -8.6 +/- 4.6 kg, HP: -9.0 +/- 4.8 kg, CON+RT: -10.5 +/- 5.1 kg, HP+RT: -13.8 +/- 6.0 kg], fat mass [CON: -6.4 +/- 3.4 kg, HP: -6.7 +/- 4.0 kg, CON+RT: -7.9 +/- 3.7 kg, HP+RT: -11.1 +/- 3.7 kg], and WC [CON: -8.2 +/- 4.6 cm, HP: -8.9 +/- 3.9 cm, CON+RT: -11.3 +/- 4.6 cm, HP+RT: -13.7 +/- 4.6 cm]). There was an overall reduction (P < 0.001) in fat-free mass (-2.0 +/- 2.3 kg), blood pressure (-15/8 +/- 10/6 mmHg), glucose (-2.1 +/- 2.2 mmol/l), insulin (-4.7 +/- 5.4 mU/l), A1C (-1.25 +/- 0.94%), triglycerides (-0.47 +/- 0.81 mmol/l), total cholesterol (-0.67 +/- 0.69 mmol/l), and LDL cholesterol (-0.37 +/- 0.53 mmol/l), with no difference between groups (P >or= 0.17). CONCLUSIONS An energy-restricted HP diet combined with RT achieved greater weight loss and more favorable changes in body composition. All treatments had similar improvements in glycemic control and CVD risk markers.

Long-term effects of weight loss with a very low carbohydrate and low fat diet on vascular function in overweight and obese patients

OBJECTIVE

To compare the effects of an energy reduced very low carbohydrate, high saturated fat diet (LC) and an isocaloric high carbohydrate, low fat diet (LF) on endothelial function after 12 months.

DESIGN AND SUBJECTS

Forty-nine overweight or obese patients (age 50.0 +/- 1.1 years, BMI 33.7 +/- 0.6 kg m(-2)) were randomized to either an energy restricted ( approximately 6-7 MJ), planned isocaloric LC or LF for 52 weeks. Body weight, endothelium-derived factors, flow-mediated dilatation (FMD), adiponectin, augmentation index (AIx) and pulse wave velocity (PWV) were assessed. All data are mean +/- SEM.

RESULTS

Weight loss was similar in both groups (LC -14.9 +/- 2.1 kg, LF -11.5 +/- 1.5 kg; P = 0.20). There was a significant time x diet effect for FMD (P = 0.045); FMD decreased in LC (5.7 +/- 0.7% to 3.7 +/- 0.5%) but remained unchanged in LF (5.9 +/- 0.5% to 5.5 +/- 0.7%). PWV improved in both groups (LC -1.4 +/- 0.6 m s(-1), LF -1.5 +/- 0.6 m s(-1); P = 0.001 for time) with no diet effect (P = 0.80). AIx and VCAM-1 did not change in either group. Adiponectin, eSelectin, tPA and PAI-1 improved similarly in both groups (P < 0.01 for time).

CONCLUSION

Both LC and LF hypoenergetic diets achieved similar reductions in body weight and were associated with improvements in PWV and a number of endothelium-derived factors. However, the LC diet impaired FMD suggesting chronic consumption of a LC diet may have detrimental effects on endothelial function.

High protein diets decrease total and abdominal fat and improve CVD risk profile in overweight and obese men and women with elevated triacylglycerol

BACKGROUND AND AIMS

It is unclear whether high protein weight loss diets have beneficial effects on weight loss, abdominal fat mass, lipids, glucose and insulin compared to conventional low fat diets in subjects at increased risk of cardiovascular disease (CVD) because of elevated glucose and triglyceride concentrations. Our objective was to determine the effects of high protein (HP) compared to standard protein (SP) diets on CVD risk in obese adults.

METHODS AND RESULTS

Data from three, 12 week, randomized parallel trials with subjects assigned to either HP or SP diet (5500-6500 kJ/day) were pooled. Weight, body composition (dual energy X-ray absorptiometry), lipids, insulin and glucose were measured before and after weight loss. Data from 215 subjects (49.9+/-9.8 years, BMI 33.5+/-3.7 kg/m(2)), 108 HP, 107 SP were analyzed. Weight loss (HP diet 7.82+/-0.37 kg; SP diet 7.65+/-0.39 kg, NS) and total fat loss were not different (HP 6.8+/-4.3 kg; LP 6.4+/-4.7 kg, NS on intention to treat analysis). The reduction in triacylglycerol (TAG) was greater on HP than SP 0.48+/-0.07 mmol/L vs 0.27+/-0.06 mmol/L, (P<0.001). Subjects with TAG greater than the median (>1.54 mmol/L at baseline) lost more weight (HP 8.5+/-0.6; SP 6.9+/-0.6 kg, P=0.01, diet by TG group), total (HP 6.17+/-0.50 kg; SP 4.52+/-0.52 kg, P=0.007) and abdominal fat (HP 1.92+/-0.17 kg; SP 1.23+/-0.19 kg, P=0.005) on HP. Total cholesterol (12 vs 6%, HP vs SP) and TAG (39 vs 20%, HP vs SP) decreased to a greater extent in these subjects (both P</=0.05) on HP.

CONCLUSION

Short-term high protein weight loss diets had beneficial effects on total cholesterol and triacylglycerol in overweight and obese subjects and achieved greater weight loss and better lipid results in subjects at increased risk of CVD. These observations provide further information regarding the utility of this dietary approach in effectively managing body weight and composition and reducing CVD risk in overweight and obese individuals.

Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo

BACKGROUND

Long-term weight loss and cardiometabolic effects of a very-low-carbohydrate, high-saturated-fat diet (LC) and a high-carbohydrate, low-fat diet (LF) have not been evaluated under isocaloric conditions.

OBJECTIVE

The objective was to compare an energy-controlled LC diet with an LF diet at 1 y.

DESIGN

Men and women (n = 118) with abdominal obesity and at least one additional metabolic syndrome risk factor were randomly assigned to either an energy-restricted (approximately 6-7 MJ) LC diet (4%, 35%, and 61% of energy as carbohydrate, protein, and fat, respectively) or an isocaloric LF diet (46%, 24%, and 30% of energy as carbohydrate, protein, and fat, respectively) for 1 y. Weight, body composition, and cardiometabolic risk markers were assessed.

RESULTS

Sixty-nine participants (59%) completed the trial: 33 in the LC group and 36 in the LF group. Both groups lost similar amounts of weight (LC: -14.5 +/- 1.7 kg; LF: -11.5 +/- 1.2 kg; P = 0.14, time x diet) and body fat (LC: -11.3 +/- 1.5 kg; LF: -9.4 +/- 1.2 kg; P = 0.30). Blood pressure, fasting glucose, insulin, insulin resistance, and C-reactive protein decreased independently of diet composition. Compared with the LF group, the LC group had greater decreases in triglycerides (-0.36 +/- 0.15 mmol/L; 95% CI: -0.67, -0.05 mmol/L; P = 0.011), increases in HDL cholesterol (0.23 +/- 0.09 mmol/L; 95% CI: 0.06, 0.40 mmol/L; P = 0.018) and LDL cholesterol (0.6 +/- 0.2 mmol/L; 95% CI: 0.2, 1.0 mmol/L; P = 0.001), and a greater but nonsignificant increase in apolipoprotein B (0.08 +/- 0.04 g/L; 95% CI: -0.004, 0.171 g/L; P = 0.17).

CONCLUSIONS

Under planned isoenergetic conditions, as expected, both dietary patterns resulted in similar weight loss and changes in body composition. The LC diet may offer clinical benefits to obese persons with insulin resistance. However, the increase in LDL cholesterol with the LC diet suggests that this measure should be monitored. This trial was registered with the Australian New Zealand Clinical Trials Registry at (http://www.anzctr.org.au) as ACTR 12606000203550.

Effects of a low-salt diet on flow-mediated dilatation in humans

BACKGROUND

The effect of salt reduction on vascular function, assessed by brachial artery flow-mediated dilatation (FMD), is unknown.

OBJECTIVE

Our aim was to compare the effects of a low-salt (LS; 50 mmol Na/d) diet with those of a usual-salt (US; 150 mmol Na/d) diet on FMD.

DESIGN

This was a randomized crossover design in which 29 overweight and obese normotensive men and women followed an LS diet and a US diet for 2 wk. Both diets had similar potassium and saturated fat contents and were designed to ensure weight stability. After each intervention, FMD, pulse wave velocity, augmentation index, and blood pressure were measured.

RESULTS

FMD was significantly greater (P = 0.001) with the LS diet (4.89 +/- 2.42%) than with the US diet (3.37 +/- 2.10%), systolic blood pressure was significantly (P = 0.02) lower with the LS diet (112 +/- 11 mm Hg) than with the US diet (117 +/- 13 mm Hg), and 24-h sodium excretion was significantly lower (P = 0.0001) with the LS diet (64.1 +/- 41.3 mmol) than with the US diet (156.3 +/- 56.7 mmol). There was no correlation between change in FMD and change in 24-h sodium excretion or change in blood pressure. No significant changes in augmentation index or pulse wave velocity were observed.

CONCLUSIONS

Salt reduction improves endothelium-dependant vasodilation in normotensive subjects independently of the changes in measured resting clinic blood pressure. These findings suggest additional cardioprotective effects of salt reduction beyond blood pressure reduction. The trial is registered with the Australian and New Zealand Clinical Trials Registry (unique identifier: ANZCTR12607000381482; http://www.anzctr.org.au/trial_view.aspx?ID=82159).

Effect of a low-resource-intensive lifestyle modification program incorporating gymnasium-based and home-based resistance training on type 2 diabetes risk in Australian adults

OBJECTIVE

The purpose of this study was to assess the effectiveness of a low-resource-intensive lifestyle modification program incorporating resistance training and to compare a gymnasium-based with a home-based resistance training program on diabetes diagnosis status and risk.

RESEARCH DESIGN AND METHODS

A quasi-experimental two-group study was undertaken with 122 participants with diabetes risk factors; 36.9% had impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) at baseline. The intervention included a 6-week group self-management education program, a gymnasium-based or home-based 12-week resistance training program, and a 34-week maintenance program. Fasting plasma glucose (FPG) and 2-h plasma glucose, blood lipids, blood pressure, body composition, physical activity, and diet were assessed at baseline and week 52.

RESULTS

Mean 2-h plasma glucose and FPG fell by 0.34 mmol/l (95% CI -0.60 to -0.08) and 0.15 mmol/l (-0.23 to -0.07), respectively. The proportion of participants with IFG or IGT decreased from 36.9 to 23.0% (P = 0.006). Mean weight loss was 4.07 kg (-4.99 to -3.15). The only significant difference between resistance training groups was a greater reduction in systolic blood pressure for the gymnasium-based group (P = 0.008).

CONCLUSIONS

This intervention significantly improved diabetes diagnostic status and reduced diabetes risk to a degree comparable to that of other low-resource-intensive lifestyle modification programs and more intensive interventions applied to individuals with IGT. The effects of home-based and gymnasium-based resistance training did not differ significantly.

Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity

BACKGROUND

The effects of a very-low-carbohydrate, high-saturated-fat weight-loss diet (LC) on brachial artery flow-mediated dilatation (FMD) and markers of endothelial function are unknown.

OBJECTIVE

The effect of an LC on markers of endothelial function and cardiovascular disease (CVD) risk was compared with that of an isocaloric high-carbohydrate, low-saturated-fat diet (HC).

DESIGN

FMD and markers of endothelial function (n = 70) and CVD risk were measured before and after 8 wk of weight loss. Ninety-nine subjects aged 50.0 +/- 8.3 y with a body mass index (in kg/m2) of 33.7 +/- 4.1 completed the study.

RESULTS

Mean (+/-SD) FMD did not change significantly (P = 0.55) with either diet. Pulse wave velocity improved with both diets (P < 0.01). Endothelial markers, E- and P selectin, intracellular and cellular-adhesion molecule-1, tissue-type plasminogen activator, and plasminogen activator inhibitor-1 decreased (P < 0.001), with no diet effect. Adiponectin did not change significantly. More weight (P = 0.05 for diet x time interaction) and more abdominal fat mass (P = 0.05 for diet x time interaction) were lost with the LC than with the HC. LDL cholesterol decreased more with the HC than with the LC (P < 0.05, time x diet), and C-reactive protein decreased more with the HC than with the LC (P < 0.05 for diet x time interaction). Homocysteine increased more with the LC (P < 0.01 for diet x time interaction). Folate decreased with the LC and increased with the HC (P < 0.05, time; P < 0.001 for diet x time interaction).

CONCLUSION

An LC does not impair FMD. We observed beneficial effects of both diets on most of the CVD risk factors measured. This trial was registered with the Australian Clinical Trials Registry as ACTR N0 12606000203550.

Long-term effects of a high-protein weight-loss diet

BACKGROUND

Evidence that high-protein diets are an effective strategy for the maintenance of long-term weight loss is limited.

OBJECTIVE

The objective was to determine the efficacy of a higher protein intake on the maintenance of weight loss after 64 wk of follow-up.

DESIGN

Seventy-nine healthy women with a mean (+/-SD) age of 49+/-9 y and a body mass index (in kg/m2) of 32.8+/-3.5 completed an intensive 12-wk weight-loss program and 52 wk of follow-up to compare the effects on weight-loss maintenance of a high-protein (HP) diet (34% of energy) or a high-carbohydrate (HC) diet (64% of energy).

RESULTS

Mean (+/-SD) weight loss was not significantly different between groups: (HP: 4.6+/-5.5 kg; HC: 4.4+/-6.1 kg). Protein intake (g) from dietary records at 64 wk was directly related to weight loss (P<0.0001), accounting for 15% of the variance. Protein intake as a percentage of energy was also related to weight change (P=0.003), accounting for 10% of the variance. In the upper tertile (88 g protein/d), weight loss was 6.5+/-7.5 and 3.4+/-4.4 kg (P=0.03) in the 2 lower tertiles, respectively. This difference did not translate to a difference in central fat loss between groups. Lipids, glucose, insulin, C-reactive protein, and homocysteine all improved with weight loss and were not significantly different between groups. HDL cholesterol rose by 20%. Higher serum vitamin B-12 was observed in the HP group, and folate concentrations were not significantly different between groups.

CONCLUSIONS

A reported higher protein intake appears to confer some weight-loss benefit. Cardiovascular disease risk factors, biomarkers of disease, and serum vitamins and minerals improved with no differences between groups.

The effect of milk protein on the bioavailability of cocoa polyphenols

In order to determine whether milk proteins interact with cocoa polyphenols to modulate the uptake and concentration of polyphenols in plasma, 24 middle-aged men and women consumed 2 g of chocolate polyphenols, plus sugar and cocoa butter in 200 mL water, on 2 occasions. On 1 occasion, the chocolate mix contained 2.45 g of milk proteins. Blood samples were taken fasting and at regular intervals for 8 h. Catechin and epicatechins levels were measured in these samples and no differences were seen in average concentrations between the 2 treatments. Milk protein caused a slight increase in concentration at the early time points and a decrease at the later time points. In conclusion, milk powder did not influence the average concentration of polyphenols. While it slightly accelerated absorption, this is of no physiological significance.

Moderate weight loss reduces renin and aldosterone but does not influence basal or stimulated pituitary-adrenal axis function

Body fat mass and nutrition influence secretion of the adrenocortical hormones--aldosterone and cortisol--via several mechanisms. However, there are no data on adrenocortical function following widely prescribed mild diet-induced weight loss (10%) in obese subjects. In the present study, 25 healthy obese volunteers (BMI 32.9+/-4.3 kg/m (2)) followed a 30% calorie restricted diet over 12 weeks. Hypothalamic-pituitary-adrenal (HPA) axis function was assessed by 24-hour urine free cortisol/cortisone and a 1 mcg ACTH stimulation test with measurement of total and free cortisol and corticosteroid-binding globulin (CBG). The renin-angiotensin-aldosterone system (RAAS) was assessed by measurement of plasma aldosterone and renin under salt depleted (30 mmol/d) and loading (250 mmol/d) conditions. Volunteers' weight fell by 8.5+/-0.8 kg (8.9+/-0.7%) and seated systolic blood pressure fell by 8.7+/-2.7 mmHg and diastolic blood pressure by 7.0+/-1.4 mmHg (p<0.01). Plasma aldosterone and renin levels fell significantly with weight loss (aldosterone: 853+/-156-635+/-73 pmol/l; renin: 35.4+/-7-24+/-3 mU/l, both p<0.05). The volunteers were relatively salt insensitive (mean arterial pressure change with salt intake: 4 mmHg) and this was not affected by weight loss. Moderate weight loss had no effect on 24-hour urine free cortisol/cortisone, or on basal, or ACTH-stimulated free and total cortisol, or CBG. Hence this conventional weight loss program reduces blood pressure and activity of the RAAS via an effect on renin release. Despite various described influences of fat mass and energy restriction on HPA axis function, there were no changes in basal and stimulated HPA axis function with moderate weight loss. There may be a threshold effect of weight loss/energy restriction required to alter HPA axis function, or moderate weight loss may lead to a counterbalanced effect of stimulatory and inhibitory influences on HPA axis function.

Low- and high-carbohydrate weight-loss diets have similar effects on mood but not cognitive performance

BACKGROUND

Low-carbohydrate diets are often used to promote weight loss, but their effects on psychological function are largely unknown.

OBJECTIVE

We compared the effects of a low-carbohydrate, high-fat (LCHF) diet with a conventional high-carbohydrate, low-fat (HCLF) diet on mood and cognitive function.

DESIGN

Ninety-three overweight or obese participants [x +/- SEM age: 50.2 +/- 0.8 y; body mass index (in kg/m2): 33.6 +/- 0.4] were randomly assigned to an energy-restricted ( approximately 6-7 MJ, 30% deficit), planned isocaloric LCHF diet or an HCLF diet for 8 wk. Body weight and psychological well-being were measured by using the Profile of Mood States, Beck Depression Inventory, and Spielberger State Anxiety Inventory instruments at baseline and fortnightly. Cognitive functioning (working memory and speed of processing) was assessed at baseline and week 8.

RESULTS

The LCHF diet resulted in significantly greater weight loss than did the HCLF diet (7.8 +/- 0.4 and 6.4 +/- 0.4 kg, respectively; P = 0.04). Both groups showed improvements in psychological well-being (P < 0.01 for time), with the greatest effect occurring during the first 2 wk, but there was no significant difference between groups. There were no significant between-group differences in working memory (P = 0.68), but there was a significant time x diet interaction for speed of processing (P = 0.04), so that this measure improved less in the LCHF than in the HCLF diet group.

CONCLUSIONS

Both dietary patterns significantly reduced body weight and were associated with improvements in mood. There was some evidence for a smaller improvement in cognitive functioning with the LCHF diet with respect to speed of processing, but further studies are required to determine the replicability of this finding.

Long-term weight maintenance and cardiovascular risk factors are not different following weight loss on carbohydrate-restricted diets high in either monounsaturated fat or protein in obese hyperinsulinaemic men and women

The aim of this study was to determine after 52 weeks whether advice to follow a lower carbohydrate diet, either high in monounsaturated fat or low fat, high in protein had differential effects in a free-living community setting. Following weight loss on either a high monounsaturated fat, standard protein (HMF; 50 % fat, 20 % protein (67 g/d), 30 % carbohydrate) or a high protein, moderate fat (HP) (40 % protein (136 g/d), 30 % fat, 30 % carbohydrate) energy-restricted diet (6000 kJ/d) subjects were asked to maintain the same dietary pattern without intensive dietary counselling for the following 36 weeks. Overall weight loss was 6.2 (SD 7.3) kg (P < 0.01 for time with no diet effect, 7.6 (SD 8.1) kg, HMF v. 4.8 (SD 6.6) kg, HP). In a multivariate regression model predictors of weight loss at the end of the study were sex, age and reported percentage energy from protein (R2 0.22, P < 0.05 for the whole model). Fasting plasma insulin decreased (P < 0.01, with no difference between diets), 13.9 (SD 4.6) to 10.2 (SD 5.2) mIU/l, but fasting plasma glucose was not reduced. Neither total cholesterol nor LDL-cholesterol were different but HDL was higher, 1.19 (SD 0.26) v. 1.04 (SD 0.29) (P < 0.001 for time, no diet effect), while TAG was lower, 1.87 (SD 1.23) v. 2.22 (SD 1.15) mmol/l (P < 0.05 for time, no diet effect). C-reactive protein decreased (3.97 (SD 2.84) to 2.43 (SD 2.29) mg/l, P < 0.01). Food records showed that compliance to the prescribed dietary patterns was poor. After 1 year there remained a clinically significant weight loss and improvement in cardiovascular risk factors with no adverse effects of a high monounsaturated fat diet.

Effects of weight loss on a low-carbohydrate diet on flow-mediated dilatation, adhesion molecules and adiponectin

Our aim was to determine whether short-term weight loss on a low-carbohydrate/low-saturated fat diet improved endothelial function compared with a conventional high-carbohydrate diet, as this diet is expected to lower both blood glucose and LDL-cholesterol. In a randomised parallel design of two energy-restricted diets in an outpatient setting, thirty-six subjects (BMI 33 (sem 4) kg/m2) were randomised to a low- or high-carbohydrate diet both low in saturated fat. Flow-mediated dilatation (FMD), fasting glucose, insulin, lipids, adiponectin and adhesion molecules were measured at baseline, during weight loss and at 52 weeks. FMD did not change with either diet (5.2 (sem 0.6) to 5.5 (sem 0.6) %) despite weight loss of 5 % and significant reductions in glucose and insulin and LDL-cholesterol and was not different after sustained weight loss of 5 % at 52 weeks. Adiponectin fell by 6 % at 12 weeks (P = 0.1) with weight loss but rose by 17 % at 12 months (P < 0.05) with 5 % weight loss. There were no effects of diet. In contradistinction, adhesion molecules fell at 12 weeks, vascular cell adhesion molecule-1 by 14 % and intracellular adhesion molecule-1 by 13 % (both P < 0.05). There were correlations between change in adiponectin at 12 months and change in HDL (r 0.778, P < 0.01) and glucose (r - 0.563, P = 0.057). In summary, weight loss does not improve FMD. Novel cardiovascular risk factors improved at 12 weeks but the improvement in adiponectin was delayed.

Effects of meals with high soluble fibre, high amylose barley variant on glucose, insulin, satiety and thermic effect of food in healthy lean women

OBJECTIVE

To examine the effect of barley flour (barley cultivar, Hordeum Vulgare var Himalaya 292) incorporated into breakfast and lunch compared with otherwise identical meals containing white wheat flour on the thermic effect of food (TEF), subsequent food intake and metabolic parameters.

DESIGN

Randomized single blinded crossover study.

SETTING

Outpatient setting.

SUBJECTS AND METHODS

Fourteen healthy women consumed a test breakfast at 0700 h. Energy expenditure, respiratory quotient (RQ), appetite ratings using a visual analogue scale (VAS), insulin and glucose levels were measured before and after a test lunch at 1330 h. Food intake was recorded for the remainder of the day.

RESULTS

The TEF was 5% for both test lunches and meal type did not affect any variable measured by the VAS. There was an increase in post-prandial RQ above baseline (0.80) independent of treatment (0.88 and 0.90 for barley and wheat-containing meals, respectively, P<0.001). Mean area under the glycaemic response curve (AUC) for wheat-containing meals was 4.68+/-1.67 mmol/l/h, 22% higher than for the barley-containing meals (3.67+/-1.91 mmol/l/h), P=0.05. AUC of insulin in response to wheat-containing meals (78.1+/-35.3 mIU/l/h) was 32% greater than barley-containing meals (52.8+/-24.7 mU/l/h), P<0.02. Ad libitum food intake over the next 10 h was reduced by 23% (9.6 vs 11.0 MJ, P<0.05) after the wheat-containing meals compared to the barley-containing glycaemic index meals.

CONCLUSION

Inclusion of an ingredient containing increased soluble fibre and amylose did not reduce spontaneous food intake but rather was associated with higher subsequent energy intakes despite its reduced glycaemic and insulinemic effects.

SPONSORSHIP

CSIRO, Human Nutrition, Adelaide, Australia.

Health benefits of herbs and spices: the past, the present, the future

Herbs and spices have a traditional history of use, with strong roles in cultural heritage, and in the appreciation of food and its links to health. Demonstrating the benefits of foods by scientific means remains a challenge, particularly when compared with standards applied for assessing pharmaceutical agents. Pharmaceuticals are small-molecular-weight compounds consumed in a purified and concentrated form. Food is eaten in combinations, in relatively large, unmeasured quantities under highly socialised conditions. The real challenge lies not in proving whether foods, such as herbs and spices, have health benefits, but in defining what these benefits are and developing the methods to expose them by scientific means.

CULTURAL ASPECTS

The place of herbs and spices in the diet needs to be considered in reviewing health benefits. This includes definitions of the food category and the way in which benefits might be viewed, and therefore researched. Research may focus on identifying bioactive substances in herbs and spices, or on their properties as a whole food, and/or be set in the context of a dietary cuisine.

THE ROLE OF HERBS AND SPICES IN HEALTH

The antioxidant properties of herbs and spices are of particular interest in view of the impact of oxidative modification of low-density lipoprotein cholesterol in the development of atherosclerosis. There is level III-3 evidence (National Health and Medical Research Council [NHMRC] levels of evidence) that consuming a half to one clove of garlic (or equivalent) daily may have a cholesterol-lowering effect of up to 9%. There is level III-1 evidence that 7.2 g of aged garlic extract has been associated with anticlotting (in-vivo studies), as well as modest reductions in blood pressure (an approximate 5.5% decrease in systolic blood pressure). A range of bioactive compounds in herbs and spices have been studied for anticarcinogenic properties in animals, but the challenge lies in integrating this knowledge to ascertain whether any effects can be observed in humans, and within defined cuisines. Research on the effects of herbs and spices on mental health should distinguish between cognitive decline associated with ageing and the acute effects of psychological and cognitive function. There is level I and II evidence for the effect of some herbal supplements on psychological and cognitive function. There is very limited scientific evidence for the effects of herbs and spices on type 2 diabetes mellitus, with the best evidence being available for the effect of ginseng on glycaemia, albeit based on four studies. More research is required, particularly examining the effects of chronic consumption patterns. With increasing interest in alternatives to non-steroidal anti-inflammatory agents in the management of chronic inflammation, research is emerging on the use of food extracts. There is level II evidence for the use of ginger in ameliorating arthritic knee pain; however, the improvement is modest and the efficacy of ginger treatment is ranked below that of ibuprofen. More definitive research is required.

PUBLIC HEALTH AND DIETARY IMPLICATIONS

Recommendations for intakes of food in the Australian guide to healthy eating do not yet include suggested intakes of herbs and spices. Future consideration should be given to including more explicit recommendations about their place in a healthy diet. In addition to delivering antioxidant and other properties, herbs and spices can be used in recipes to partially or wholly replace less desirable ingredients such as salt, sugar and added saturated fat in, for example, marinades and dressings, stir-fry dishes, casseroles, soups, curries and Mediterranean-style cooking. Vegetable dishes and vegetarian options may be more appetising when prepared with herbs and spices.

FUTURE DIRECTIONS

As several metabolic diseases and age-related degenerative disorders are closely associated with oxidative processes in the body, the use of herbs and spices as a source of antioxidants to combat oxidation warrants further attention. Immediate studies should focus on validating the antioxidant capacity of herbs and spices after harvest, as well as testing their effects on markers of oxidation. This will work in parallel with clinical trials that are aiming to establish antioxidants as mediators of disease prevention. From a dietary perspective, the functionality of herbs and spices will be exposed through consideration of their properties as foods. As with most foods, the real benefits of including them in the diet are likely to emerge with a better understanding of the attributes of health that are best supported by food, and in methodological developments addressing the evidence base for their effects. These developments are well underway through evidence-based frameworks for substantiating health claims related to foods. At present, recommendations are warranted to support the consumption of foods rich in bioactive components, such as herbs and spices. With time, we can expect to see a greater body of scientific evidence supporting the benefits of herbs and spices in the overall maintenance of health and protection from disease.

Comparison of isocaloric very low carbohydrate/high saturated fat and high carbohydrate/low saturated fat diets on body composition and cardiovascular risk

Background

It is speculated that high saturated fat very low carbohydrate diets (VLCARB) have adverse effects on cardiovascular risk but evidence for this in controlled studies is lacking. The objective of this study was to compare, under isocaloric conditions, the effects of a VLCARB to 2 low saturated fat high carbohydrate diets on body composition and cardiovascular risk.

Methods

Eighty three subjects, 48 ± 8 y, total cholesterol 5.9 ± 1.0 mmol/L, BMI 33 ± 3 kg/m² were randomly allocated to one of 3 isocaloric weight loss diets (6 MJ) for 8 weeks and on the same diets in energy balance for 4 weeks: Very Low Fat (VLF) (CHO:Fat:Protein; %SF = 70:10:20; 3%), High Unsaturated Fat (HUF) = (50:30:20; 6%), VLCARB (4:61:35; 20%)

Results

Percent fat mass loss was not different between diets VLCARB -4.5 ± 0.5, VLF-4.0 ± 0.5, HUF -4.4 ± 0.6 kg). Lean mass loss was 32-31% on VLCARB and VLF compared to HUF (21%) (P < 0.05). LDL-C increased significantly only on VLCARB by 7% (p < 0.001 compared with the other diets) but apoB was unchanged on this diet and HDL-C increased relative to the other 2 diets. Triacylglycerol was lowered by 0.73 ± 0.12 mmol/L on VLCARB compared to -0.15 ± 0.07 mmol/L on HUF and -0.06 ± 0.13 mmol/L on VLF (P < 0.001). Plasma homocysteine increased 6.6% only on VLCARB (P = 0.026). VLCARB lowered fasting insulin 33% compared to a 19% fall on HUF and no change on VLF (P < 0.001). The VLCARB meal also provoked significantly lower post prandial glucose and insulin responses than the VLF and HUF meals. All diets decreased fasting glucose, blood pressure and CRP (P < 0.05).

Conclusion

Isocaloric VLCARB results in similar fat loss than diets low in saturated fat, but are more effective in improving triacylglycerols, HDL-C, fasting and post prandial glucose and insulin concentrations. VLCARB may be useful in the short-term management of subjects with insulin resistance and hypertriacylglycerolemia.

Effect of weight loss on inflammatory and endothelial markers and FMD using two low-fat diets

OBJECTIVE

Cardiovascular disease is strongly associated with obesity and there is evidence that weight loss has positive effects on cardiovascular disease risk. The aims of this study were to compare meal replacements (MR) with a conventional low-fat diet as weight loss strategies and to examine the effect of weight loss on flow-mediated dilatation (FMD) and other markers of endothelial function in overweight Australians with raised triglycerides (TG) (> 2 mmol/l).

RESEARCH METHODS

Subjects matched for age, gender, fasting plasma TG and body mass index were randomized to two low- fat high- carbohydrate weight loss strategies (both < 6000 kJ), one using MR and the other a structured eating plan, control (C). Subjects followed both diets for 3 months. In total, 55 subjects completed the study. FMD, pulse wave velocity and blood pressure (BP) were measured at baseline and at 3 months, as were fasting blood samples for lipids, glucose, insulin, C reactive protein (CRP) and endothelium-derived factors.

RESULTS

Mean weight loss was 6.3 +/- 3.7 kg (6.0 +/- 4.2 vs 6.63 +/- 3.35 kg, MR vs C) with no difference between diet groups. TG, insulin, CRP, plasminogen activator inhibitor 1 (PAI-1) and soluble intracellular adhesion molecule-1 (sICAM1) fell after weight loss, but FMD did not change. Systolic BP fell by 8 mmHg and pulse wave velocity improved.

DISCUSSION

In subjects with elevated TG, weight loss resulted in significant improvements in cardiovascular risk markers, particularly endothelium-derived factors (PAI-1 and sICAM1). However, FMD did not improve with weight loss.

The satiating effect of dietary protein is unrelated to postprandial ghrelin secretion

CONTEXT

Increasing dietary protein relative to carbohydrate and fat enhances weight loss, at least in part by increasing satiety. The mechanism for this is unclear.

OBJECTIVE

The objective of this study was to compare the effects of isocaloric test meals with differing protein to fat ratios on fasting and postprandial ghrelin, insulin, glucose, appetite, and energy expenditure before and after weight loss on the respective dietary patterns.

DESIGN

The study design was a randomized parallel design of 12 wk of weight loss (6 MJ/d) and 4 wk of weight maintenance (7.3 MJ/d) with meals administered at wk 0 and 16.

SETTING

The study was performed at an out-patient research clinic.

PATIENTS AND OTHER PARTICIPANTS

Fifty-seven overweight (body mass index, 33.8 +/- 3.5 kg/m2) hyperinsulinemic men (n = 25) and women (n = 32) were studied.

INTERVENTIONS

High-protein/low-fat (34% protein/29% fat) or standard protein/high-fat (18% protein/45% fat) diets/meals were given.

MAIN OUTCOME MEASURES

The main outcome measures were weight loss and fasting and postprandial ghrelin, insulin, glucose, appetite, and energy expenditure before and after weight loss.

RESULTS

Weight loss (9.2 +/- 0.7 kg) and improvements in fasting and postprandial insulin and glucose occurred independently of diet composition. At wk 0 and 16, subjects wanted less to eat after the high-protein/low-fat than the standard protein/high-fat meal (P = 0.02). Fasting ghrelin increased (157.5 +/- 3.4 pg/ml or 46.6 +/- 1.0 pmol/liter; P < 0.001), and the postprandial ghrelin response improved with weight loss (P = 0.043) independently of diet composition. Postprandial hunger decreased with weight loss (P = 0.018) and was predicted by changes in fasting and postprandial ghrelin (r2 = 0.246; P = 0.004). Lean mass was the best predictor of fasting (r2 = 0.182; P = 0.003) and postprandial ghrelin (r2 = 0.096; P = 0.039) levels.

CONCLUSIONS

Exchanging protein for fat produced similar weight loss and improvements in metabolic parameters and ghrelin homeostasis. The reduced appetite observed with increased dietary protein appears not to be mediated by ghrelin homeostasis.

The role of meal replacements in obesity treatment

Effective weight loss strategies are needed to help overweight and obese people lose weight and maintain weight loss in the long term. Meal replacements for weight loss are available in the community; however, their efficacy in the longer term is not clear. This review summarizes recent evidence on the use of meal replacements as a weight loss strategy.

Flow-Mediated Dilatation Is Impaired by a High–Saturated Fat Diet but Not by a High-Carbohydrate Diet

Objective— It is unknown whether a low-fat diet, which may elevate triglycerides and lower high-density lipoprotein (HDL) cholesterol, harms the endothelium. Our aim was to determine whether a low-fat, high-carbohydrate (CARB) diet impaired endothelial vasodilation compared with high saturated fat (SFA), monounsaturated fat (MUFA), or polyunsaturated fat (PUFA) diets.

Methods and Results— Forty healthy subjects were randomly crossed over to 4, 3-week isocaloric diets high in PUFA, MUFA, or SFA, containing at least 25 g of the relevant fat or a low-fat, CARB, high–glycemic load diet. Flow-mediated dilatation (FMD), fasting blood lipids, high sensitivity C-reactive protein, plasma intercellular, and vascular adhesion molecules plasma E- and P-selectin were measured after each intervention. SFA impaired FMD compared with all other diets (5.41±2.45% versus 10.80±3.69%; P =0.01). FMD did not change on CARB relative to MUFA or PUFA, despite 23% to 39% rises in triglyceride and 10% to 15% falls in HDL cholesterol. P-selectin was highest after SFA (121±52.7 ng/mL) versus MUFA (98±44.5 ng/mL; P =0.001) and PUFA (96±36.4 ng/mL; P =0.001).

Conclusion— High SFA caused deterioration in FMD compared with high PUFA, MUFA, or CARB diets. Inflammatory responses may also be increased on this diet.

Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women

BACKGROUND

Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages.

OBJECTIVE

The objective was to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition, cardiovascular disease risk, nutritional status, and markers of bone turnover and renal function in overweight women.

DESIGN

The subjects were randomly assigned to 1 of 2 isocaloric 5600-kJ dietary interventions for 12 wk according to a parallel design: a high-protein (HP) or a high-carbohydrate (HC) diet.

RESULTS

One hundred women with a mean (+/-SD) body mass index (in kg/m(2)) of 32 +/- 6 and age of 49 +/- 9 y completed the study. Weight loss was 7.3 +/- 0.3 kg with both diets. Subjects with high serum triacylglycerol (>1.5 mmol/L) lost more fat mass with the HP than with the HC diet (x +/- SEM: 6.4 +/- 0.7 and 3.4 +/- 0.7 kg, respectively; P = 0.035) and had a greater decrease in triacylglycerol concentrations with the HP (-0.59 +/- 0.19 mmol/L) than with the HC (-0.03 +/- 0.04 mmol/L) diet (P = 0.023 for diet x triacylglycerol interaction). Triacylglycerol concentrations decreased more with the HP (0.30 +/- 0.10 mmol/L) than with the HC (0.10 +/- 0.06 mmol/L) diet (P = 0.007). Fasting LDL-cholesterol, HDL-cholesterol, glucose, insulin, free fatty acid, and C-reactive protein concentrations decreased with weight loss. Serum vitamin B-12 increased 9% with the HP diet and decreased 13% with the HC diet (P < 0.0001 between diets). Folate and vitamin B-6 increased with both diets; homocysteine did not change significantly. Bone turnover markers increased 8-12% and calcium excretion decreased by 0.8 mmol/d (P < 0.01). Creatinine clearance decreased from 82 +/- 3.3 to 75 +/- 3.0 mL/min (P = 0.002).

CONCLUSION

An energy-restricted, high-protein, low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet.

Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids

BACKGROUND

When substituted for carbohydrate in an energy-reduced diet, dietary protein enhances fat loss in women. It is unknown whether the effect is due to increased protein or reduced carbohydrate.

OBJECTIVE

We compared the effects of 2 isocaloric diets that differed in protein and fat content on weight loss, lipids, appetite regulation, and energy expenditure after test meals.

DESIGN

This was a parallel, randomized study in which subjects received either a low-fat, high-protein (LF-HP) diet (29 +/- 1% fat, 34 +/- 0.8% protein) or a high-fat, standard-protein (HF-SP) diet (45 +/- 0.6% fat, 18 +/- 0.3% protein) during 12 wk of energy restriction (6 +/- 0.1 MJ/d) and 4 wk of energy balance (7.4 +/- 0.3 MJ/d). Fifty-seven overweight and obese [mean body mass index (in kg/m(2)): 33.8 +/- 0.9] volunteers with insulin concentrations >12 mU/L completed the study.

RESULTS

Weight loss (LF-HP group, 9.7 +/- 1.1 kg; HF-SP group, 10.2 +/- 1.4 kg; P = 0.78) and fat loss were not significantly different between diet groups even though the subjects desired less to eat after the LF-HP meal (P = 0.02). The decrease in resting energy expenditure was not significantly different between diet groups (LF-HP, -342 +/- 185 kJ/d; HF-SP, -349 +/- 220 kJ/d). The decrease in the thermic effect of feeding with weight loss was smaller in the LF-HP group than in the HF-SP group (-0.3 +/- 1.0% compared with -3.6 +/- 0.7%; P = 0.014). Glucose and insulin responses to test meals improved after weight loss (P < 0.001) with no significant diet effect. Bone turnover, inflammation, and calcium excretion did not change significantly.

CONCLUSION

The magnitude of weight loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets, and neither diet had any detrimental effects on bone turnover or renal function.

Meal replacements are as effective as structured weight-loss diets for treating obesity in adults with features of metabolic syndrome

Meal replacements are widely used as a weight-loss strategy; however, their effectiveness outside controlled clinical trial environments is unknown. We compared meal replacements with a structured weight-reduction diet in overweight/obese Australians with raised triglycerides. In a randomized parallel design, 2 groups [meal replacement (MR) and control (C)] of 66 matched subjects underwent a 6000 kJ intervention for 3 mo (stage 1) and a further 3 mo (stage 2). The groups were provided oral and written information. The C group was supplied with shopping vouchers and followed a low fat/energy diet. The MR group was supplied with Slim-Fast trade mark products for 2 meals (1800 kJ) and consumed a low-fat evening meal. Clients were weighed every 2 wk and received structured supervision without professional dietary input, with compliance assessed by 3-d weighed food records. Blood biomarkers were used to assess fruit/vegetable intake and a questionnaire was used to assess attitudes to treatment. Fifty-five subjects completed stage 1 (withdrawals: 7 in the MR group, 4 in the C group) and 42 subjects completed stage 2. Weight loss was 6.0 +/- 4.2 kg (6.3%) for the MR group and 6.6 +/- 3.4 kg (6.9%) for the C group at 3 mo, and 9.0 +/- 6.9 kg (9.4%) for the MR group and 9.2 +/- 5.1 kg (9.3%) for the C group at 6 mo (different over time within but not between treatments). Serum folate and plasma beta-carotene were higher in the MR group. Plasma homocysteine fell in both groups (P < 0.005). Dietary fiber intake was higher in the C group (P < 0.02) and calcium was higher in the MR group (P < 0.001). We concluded meal replacement is equally effective for losing weight compared with conventional but structured weight-loss diets. Dietary compliance and convenience were viewed more favorably by participants who consumed meal replacements than by those in a conventional weight-loss program.

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.

Trans fatty acids in adipose tissue and the food supply are associated with myocardial infarction

Metabolic studies have clearly shown that trans fatty acids (TFAs) elevate LDL and lower HDL cholesterol. Epidemiologic studies showed a relation between TFA intake and the risk of myocardial infarction (MI), but studies examining adipose tissue TFAs have not uniformly confirmed this. We performed a case control study examining both adipose tissue levels and dietary intake of TFAs and first MI. Between 1995 and 1997, 209 cases of first MI completed a 300-item FFQ and 79 had an adipose tissue biopsy; 179 matched controls completed the FFQ and 167 had a biopsy. During the course of the study (mid-1996), TFAs were eliminated from margarines sold in Australia. Cases biopsied before mid-1996 had greater levels of trans 18:1(n-9) (32% P < 0.03) and trans 18:1(n-11) (23%, P < 0.001) than controls biopsied before mid-1996. After June 1996, there were no differences between cases and controls in any of the adipose tissue TFAs measured. Logistic regression showed that trans 18:1(n-11) (P = 0.03) was an independent predictor of a first MI. Cases consumed 0.5 g/d (P = 0.002) more TFAs than controls. Subjects in the highest quintile of TFA intake had an OR for first MI of 2.1 (95% CI, 1.1-4.3), which was not independent of saturated fat intake. Apparent TFA intake from margarine was related to adipose tissue 18:1t[(n-9) and (n-10)] in 1995 (r = 0.66, 0.66, respectively). We conclude that TFAs in adipose tissue are associated with an increased risk of coronary artery disease and rapidly disappear from adipose tissue when not included in margarines.

Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects

OBJECTIVE

To compare the long-term compliance and effects of two low-fat diets differing in carbohydrate to protein ratio on body composition and biomarkers of cardiovascular disease risk in obese subjects with hyperinsulinemia.

DESIGN

Outpatient, parallel, clinical intervention study of two groups of subjects randomly assigned to either a standard protein (SP; 15% protein, 55% carbohydrate) or high-protein (HP; 30% protein, 40% carbohydrate) diet, during 12 weeks of energy restriction (approximately 6.5 MJ/day) and 4 weeks of energy balance (approximately 8.3 MJ/day). Subsequently, subjects were asked to maintain the same dietary pattern for the succeeding 52 weeks with minimal professional support.

SUBJECTS

A total of 58 obese, nondietetic subjects with hyperinsulinemia (13 males/45 females, mean age 50.2 y, mean body mass index (BMI) 34.0 kg/m2, mean fasting insulin 17.8 mU/l) participated in the study.

MEASUREMENTS

: Body composition, blood pressure, blood lipids, fasting glucose, insulin, CRP and sICAM-1 were measured at baseline and at weeks 16 and 68. Urinary urea/creatinine ratio was measured at baseline, week 16 and at 3 monthly intervals thereafter.

RESULTS

In total, 43 subjects completed the study with similar dropouts in each group (P=0.76). At week 68, there was net weight loss (SP -2.9+/-3.6%, HP -4.1+/-5.8%; P<0.44) due entirely to fat loss (P<0.001) with no diet effect [corrected]. Both diets significantly increased HDL cholesterol concentrations (P<0.001) and decreased fasting insulin, insulin resistance, sICAM-1 and CRP levels (P<0.05). Protein intake was significantly greater in HP during the initial 16 weeks (P<0.001), but decreased in HP and increased in SP during 52-week follow-up, with no difference between groups at week 68, indicating poor long-term dietary adherence behaviour to both dietary patterns.

CONCLUSION

Without active ongoing dietary advice, adherence to dietary intervention is poor. Nonetheless, both dietary patterns achieved net weight loss and improvements in cardiovascular risk factors.

Bone loss at the proximal femur and reduced lean mass following liver transplantation: a longitudinal study

The longevity of recipients of liver transplant may be compromised by spinal osteoporosis and vertebral fractures. However, femoral neck fractures are associated with a higher morbidity and mortality than spine fractures. As there is little information on bone loss at this clinically important site of fracture, the aim of this study was to determine whether accelerated bone loss occurs at the proximal femur following transplantation. Bone mineral density and body composition were measured at the femoral neck, lumbar spine and total body, using dual x-ray absorptiometry in 22 men and 19 women, age 46 +/- 1.4 y (mean +/- SEM) before and at a mean of 19 mo after surgery (range 3-44). Results were expressed in absolute terms (g/cm2) and as a z score. Before transplantation, z scores for bone mineral density were reduced at the femoral neck (-0.47 +/- 0.21 SD), trochanter (-0.56 +/- 0.19 SD), Ward's triangle (-0.35 +/- 0.14 SD), lumbar spine (-0.76 +/- 0.13 SD), and total body (-0.78 +/- 0.15 SD) (all P < 0.01 to < 0.001). Following transplantation, bone mineral density decreased by 8.0 +/- 1.7% at the femoral neck (P < or = 0.01) and by 2.0 +/- 1.2% at the lumbar spine (P < or = 0.05). Total weight increased by 12.2 +/- 2.3%, lean mass decreased by 5.7 +/- 1.4%, while fat mass increased from 24.1 +/- 2.0% to 35.1 +/- 1.8% (all P < or = 0.001). Patients with end-stage liver disease have reduced bone mineral density. Liver transplantation is associated with a rapid decrease in bone mineral density at the proximal femur, further increasing fracture risk and a reduction in lean (muscle) mass, which may also predispose to falls. Prophylactic therapy to prevent further bone loss should be considered in patients after liver transplantation.

Hand grip dynamometry as a predictor of postoperative complications reappraisal using age standardized grip strengths

A mechanical hand grip dynamometer was used to derive age- and sex-related standard grip strengths from 247 healthy volunteers between 16 and 95 yr old. Preoperative grip strength was measured in 90 patients and related to postoperative complication rates. A grip strength of 85% standard for age and sex was found to be the most effective cut-off for prediction of postoperative complications in terms of sensitivity and specificity, predicting 74% of the complications (p less than 0.05). Specificity is improved over previously published standards related to sex alone especially when assessing the elderly patient (50% vs 21%). A grip strength below the recommended cut-off for age and sex suggests that the patient is in a high-risk group and demands further investigation of nutritional status. Studies of pre-operative nutritional support for the at risk group need to be undertaken.

Renal clearance of pancreatic and salivary amylase relative to creatinine in patients with chronic renal insufficiency

Pancreatic and salivary amylase/creatinine clearance ratios in patients with various degrees of renal impairment were compared with those obtained for control subjects. In chronic renal insufficiency (mean GFR 30 ml/min +/- 15 SD; n = 13) the clearance ratios for pancreatic (mean 3.5 +/- 1.85 SD) and salivary (mean 2.3 +/- 1.3 SD) amylase were significantly higher (P less than 0.05) than those in controls. Corresponding control values (n = 26) were 2.64 +/- 0.86 (pancreatic) and 1.64 +/- 0.95 (salivary). Three patients showed values above the normal limit. In the diabetic group (mean GFR 41 ml/min +/- 22 SD; n = 10) salivary amylase/creatinine clearance ratios (mean 2.36 +/- 1.55 SD) were significantly higher than in controls (P less than 0.05). Three patients showed raised values. Pancreatic amylase clearance was raised in only one of these patients. Three patients with terminal disease (mean GFR 10 ml/min) showed markedly raised (two- to threefold) clearance ratios for both salivary and pancreatic amylase. Of a total of 26 patients, eight had increased total amylase/creatinine clearance ratios. Pancreatic amylase/creatinine clearance was increased in seven patients, while nine patients showed raised salivary amylase/creatinine ratios. Patients with raised clearance ratios did not have clinical evidence of pancreatitis. We suggest that, in the presence of impaired renal function, a high amylase/creatinine clearance ratio need not be indicative of pancreatic disease.

A new quantitative procedure for proteinuria

Abnormalities of tubular cells were treated by administration of nephrotoxin and studied by specialized gel filtration methods to discern early quantitative and qualitative changes in proteinuria. Dogs given nephrotoxic doses of Diglycoaldehyde, alpha-(hydroxymethyl)-alpha1-(6-hydroxy-9H-purine-9-yl) 60 mg per kg per day intravenously, for 3 days showed a marked reduction in effective renal plasma flow from 264.91 +/- 90.05 ml per min to 125.0 +/- 19.0 ml per min as measured by 131I sodium iodohippurate, and corresponding decrease in total renal perfusion by 131I xenon wash-out from 222.2 +/- 8.6 to 124.0 +/- 28.38. However, after treating four dogs with 20 mg per kg, an increase in effective renal plasma flow was obtained. Histologic changes of glomerular and tubular damage were demonstrated. Urine from this same series of animals was examined on a daily basis by sucrose-acrylamide gradient gel centrifugation together with ultraviolet scanning. Specific patterns were also obtained using dialyzed urine which eliminated molecules greater than 3500 mol wt. The ultraviolet pattern data were digitized and analyzed on computers to augment pattern recognition. These techniques indicted that molecules (3500 mol wt or less) were excreted in response to a known nephrotoxic agent, establishing early distinctive changes in tubular cells and also relating to alteration in renal function.

Plasma amino acids and protein levels in chronic renal failure and changes caused by oral supplements of essential amino acids

1. Plasma amino acids and six proteins have been measured in patients with chronic renal failure receiving low protein diets before and after oral supplementation with essential amino acids. 2. All the patients on low protein diets had a lower percentage of essential amino acids in their plasma than normal subjects but after supplementation, plasma levels increased significantly with minimal increase in non-essential amino acids or urea nitrogen. 3. Mean levels of plasma transferrin, complement C3 and globulin Gc were lower and plasma prealbumin higher in patients than in normal subjects. Plasma complement C4 and albumin were not different from normal. 4. Seven out of nine patients who tolerated the supplementation showed a significant increase in plasma transferrin, prealbumin and complement C3 but not in complement C4, globulin Gc or albumin. 5. Correlations between the percentage of essential amino acids and each of plasma transferrin, prealbumin and complement C3 and also between several of the plasma proteins further substantiate their value in the assessment of dietary intake in chronic renal failure. 6. The value of amino acid supplementation on low protein diets in chronic renal failure is discussed in relation to these observations.