Effect of Improving Dietary Quality on Arterial Stiffness in Subjects with Type 1 and Type 2 Diabetes: A 12 Months Randomised Controlled Trial

People with diabetes have accelerated arterial stiffening. The aim of this study was to determine the effect of increasing fruit, vegetable and dairy intake for 12 months on carotid femoral pulse wave velocity (cfPWV), augmentation index (AIx), and central blood pressure (cBP), compared to a usual diet control, in people with type 1 and type 2 diabetes. In a 12 months randomised controlled trial, cfPWV, AIx and cBP were measured every 3 months. The intervention group received dietary counselling to increase consumption of fruit (+1 serving/day; 150 g/day), vegetables (+2 servings/day; 150 g/day) and dairy (+1 serving/day; 200–250 g/day) at baseline, 1, 3, 6 and 9 months. The control group continued on their usual diet. One hundred and nine participants were randomised and 92 (intervention n = 45; control n = 47) completed. At 3 months, fruit (184 g/day; p = 0.001) and dairy (83 g/day; p = 0.037) intake increased in the intervention group compared with the control group but this increase was not maintained at 12 months. After adjustment for baseline measurements there was no time by treatment effect for central systolic or diastolic BP, AIx or cfPWV. A time effect existed for AIx which modestly increased over time. Peripheral diastolic BP and central pulse pressure were improved in the intervention group compared with the control group at 12 months. In the cohort with type 1 and type 2 diabetes, improving dietary quality by increasing consumption of fruit, vegetables and dairy did not improve cBP, AIx or cfPWV, compared with a control group continuing on their usual diet, after 12 months.

Fructose acute effects on glucose, insulin, and triglyceride after a solid meal compared with sucralose and sucrose in a randomized crossover study

BACKGROUND

Fructose, which is a sweetener with a low glycemic index, has been shown to elevate postprandial triglyceride compared with glucose. There are limited data on the effect of fructose in a solid mixed meal containing starch and protein.

OBJECTIVE

We determined the effects of sucrose, fructose, and sucralose on triglyceride, glucose, and insulin in an acute study in healthy, overweight, and obese individuals.

DESIGN

The study had a randomized crossover design. Twenty-seven participants with a mean age of 44 y and a mean body mass index (in kg/m(2)) of 26 completed the study. Fructose (52 g), sucrose (65 g), and sucralose (0.1 g) were delivered as sweet-taste-balanced muffins with a total fat load (66 g). Blood samples were taken at baseline and every 30 min for 4-h glucose, triglyceride, and insulin concentrations, and the area under the curve (AUC) and the incremental area under the curve (iAUC) were analyzed.

RESULTS

No significant difference was shown between the 3 sweeteners for triglyceride and glucose concentrations and the AUC. The glucose iAUC was lower for fructose than for sucrose and sucralose (P < 0.05). Insulin concentrations differed significantly by the type of muffin (P = 0.001), the interaction of time by type of muffin (P = 0.035), the AUC (P < 0.001), and the iAUC (P < 0.001). Fructose had a significantly lower insulin response than that of either sucrose (P-treatment = 0.006) or sucralose (P-treatment = 0.041).

CONCLUSIONS

Fructose, at a moderate dose, did not significantly elevate triglyceride compared with sucrose or sucralose and lowered the glucose iAUC. These results indicate that these sweeteners, at an equivalent sweetness, can be used in normal solid meals. Fructose showed a lower insulin response, which may be beneficial in the long term in individuals at risk of type 2 diabetes. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12615000279527.

Acute effect of red meat and dairy on glucose and insulin: a randomized crossover study

BACKGROUND

In contrast with some epidemiologic evidence, our previous research showed that a 4-wk diet that was high in low-fat dairy reduced insulin sensitivity compared with the effect of a diet that was high in red meat.

OBJECTIVE

We investigated whether a dairy meal would produce a greater insulin response than a carbohydrate-matched red meat meal would, which might account for the change in insulin sensitivity.

DESIGN

One meal contained lean red meat, bread, and orange juice, and the other meal contained skim milk, low-fat yogurt, cheese, and bread. Meals were isoenergetic, equal in macronutrient profile, and consumed 1 wk apart. Glucose, insulin, and triglycerides were measured before and 30, 60, 90, 120, 150, and 180 min after meal consumption. Differences between meals were tested with the use of a repeated-measures ANOVA and paired sample t tests.

RESULTS

Nineteen men and 24 women [mean ± SD age: 50.8 ± 16.0 y; body mass index (in kg/m(2)): 30.0 ± 3.5] completed the study. Twenty-two participants had normal glucose tolerance, and 21 participants had impaired fasting glucose or impaired glucose tolerance. The red meat meal resulted in a higher glucose response at 30 min after consumption (P < 0.001); however, the glucose total AUC was not different between meals (P = NS). The mean ± SEM incremental AUC (iAUC) for glucose was significantly higher after the dairy meal than after the red meat meal (2.23 ± 0.49 compared with 0.88 ± 0.57 mmol/L · 3 h, respectively; P = 0.004). The insulin total AUC and iAUC were not different between meals (iAUC: 159.65 ± 20.0 mU/L · 3 h for red meat compared with 167.49 ± 24.1 mU/L · 3 h for dairy; P = NS).

CONCLUSIONS

Lean red meat and low-fat dairy produced a similar glycemic response. The higher glucose response 30 min after consumption of the red meat meal was likely attributable to differences in the glycemic load between orange juice and milk and yogurt. An insulinotropic effect of dairy was not observed. This trial was registered at www.anzctr.org.au as ACTRN12615000164594.

Effect of improving dietary quality on carotid intima media thickness in subjects with type 1 and type 2 diabetes: a 12-mo randomized controlled trial

BACKGROUND

People with diabetes are at a heightened risk of cardiovascular disease compared with the general population. To our knowledge, randomized controlled trials investigating the effect of improving dietary quality on carotid intima media thickness, a marker of subclinical atherosclerosis and predictor of cardiovascular disease, have not been conducted in populations with diabetes.

OBJECTIVE

We aimed to determine whether increasing fruit (+1 serving; 150 g/d), vegetable (+2 servings; 150 g/d), and dairy (+1 serving; 200-250 g/d) intakes slows 12-mo common carotid artery intima media thickness (CCA IMT) progression, compared with a control group continuing to consume their usual diet, in people with type 1 and type 2 diabetes.

DESIGN

A 12-mo randomized controlled trial was conducted. The primary outcome was mean CCA IMT, measured at baseline and 12 mo, with B-mode ultrasound. Participants in the intervention group received counseling from a dietitian at baseline and 1, 3, 6, and 9 mo, and compliance was measured with a food-frequency questionnaire at baseline, 3 mo, and 12 mo. The control group continued consuming their usual diet.

RESULTS

In total, 118 participants completed the study. Vegetable (46 g/d; 95% CI: 14, 77 g/d; P < 0.001) and fruit (179 g/d; 95% CI: 119, 239 g/d; P < 0.001) intakes were increased at 3 mo in the intervention group compared with the control group. This increase was not maintained at 12 mo, but intake increased overall in the cohort (fruit, 48 g/d; vegetables, 14 g/d). An increase in dairy consumption was not achieved, but yogurt intake was higher in the intervention group at 3 mo (38 g; 95% CI: 12, 65 g; P < 0.001); this was not maintained at 12 mo. At 12 mo, CCA IMT regressed (mean ± SD: -0.01 ± 0.04 mm; P < 0.001), with a greater effect in the treatment group (mean ± SD: -0.02 ± 0.04 mm compared with -0.004 ± 0.04 mm; P = 0.009).

CONCLUSION

Improving dietary quality in people with well-controlled type 1 and type 2 diabetes may slow CCA IMT progression. This trial was registered at https://www.anzctr.org.au as ACTRN12613000251729.

Salt Restriction in Diabetes

There are no long-term interventions examining the effects of salt reduction in people with diabetes, and these are urgently required. Sodium reduction is controversial as it appears that an intake below 2.5 g and above 6 g/day of salt is associated with increased cardiovascular disease risk. However, pre-existing illness leading to a lower salt intake may confound the findings. Only a few studies have prospectively collected data on the sodium intake and excretion of people with diabetes and examined hard end points. In addition, future studies need to collect more data on food intake as well as coexistent illnesses to address potential confounding. The World Health Organization recommends a reduction to less than 5 g/day salt in adults. Given that the available evidence suggests that the salt intake of people with type 2 diabetes is generally well above 6 g/day it seems reasonable to ensure individuals with diabetes have an intake below 6 g/day. However, such recommendations need to be individualized.

Red meat, dairy, and insulin sensitivity: a randomized crossover intervention study

BACKGROUND

Epidemiologic studies have linked high consumption of red and processed meat with risk of developing type 2 diabetes, whereas high dairy consumption has been associated with decreased risk, but interventions have been limited.

OBJECTIVE

We compared the effects on insulin sensitivity of consuming a diet high in lean red meat with minimal dairy, a diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat, and a control diet that contained neither red meat nor dairy.

DESIGN

A randomized crossover study was undertaken with 47 overweight and obese men and women divided into 2 groups as follows: those with normal glucose tolerance and those with impaired fasting glucose or impaired glucose tolerance. Participants followed the 3 weight-stable dietary interventions for 4 wk with glucose, insulin, and C-peptide measured by using oral-glucose-tolerance tests at the end of each diet.

RESULTS

Fasting insulin was significantly higher after the dairy diet than after the red meat diet (P < 0.01) with no change in fasting glucose resulting in a decrease in insulin sensitivity after the high-dairy diet (P < 0.05) as assessed by homeostasis model assessment of insulin resistance (HOMA-IR). A significant interaction between diet and sex was observed such that, in women alone, HOMA-IR was significantly lower after the red meat diet than after the dairy diet (1.33 ± 0.8 compared with 1.71 ± 0.8, respectively; P < 0.01). Insulin sensitivity calculated by using the Matsuda method was 14.7% lower in women after the dairy diet than after the red meat diet (P < 0.01) with no difference between diets in men. C-peptide was not different between diets.

CONCLUSION

In contrast to some epidemiologic findings, these results suggest that high consumption of dairy reduces insulin sensitivity compared with a diet high in lean red meat in overweight and obese subjects, some of whom had glucose intolerance. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12613000441718.

Effect of sodium and potassium supplementation on vascular and endothelial function: a randomized controlled trial

BACKGROUND

It is known that increased potassium and reduced sodium intakes can improve postprandial endothelial function. However, the effect of increasing potassium in the presence of high sodium in the postprandial state is not known.

OBJECTIVE

We aimed to determine the effect of high potassium and high sodium on postprandial endothelial function as assessed by using flow-mediated dilatation (FMD) and arterial compliance as assessed by using pulse wave velocity (PWV) and central augmentation index (AIx).

DESIGN

Thirty-nine healthy, normotensive volunteers [21 women and 18 men; mean ± SD age: 37 ± 15 y; BMI (in kg/m(2)): 23.0 ± 2.8] received a meal with 3 mmol K and 65 mmol Na (low-potassium, high-sodium meal (LKHN)], a meal with 38 mmol K and 65 mmol Na [high-potassium, high-sodium meal (HKHN)], and a control meal with 3 mmol K and 6 mmol Na (low-potassium, low-sodium meal) on 3 separate occasions in a randomized crossover trial. Brachial artery FMD, carotid-femoral PWV, central AIx, and blood pressure (BP) were measured while participants were fasting and at 30, 60, 90, and 120 min after meals.

RESULTS

Compared with the LKHN, the addition of potassium (HKHN) significantly attenuated the postmeal decrease in FMD (P-meal by time interaction < 0.05). FMD was significantly lower after the LKHN than after the HKHN at 30 min (P < 0.01). AIx decreased after all meals (P < 0.05). There were no significant differences in AIx, PWV, or BP between treatments over time.

CONCLUSION

The addition of potassium to a high-sodium meal attenuates the sodium-induced postmeal reduction in endothelial function as assessed by FMD. This trial was registered at http://www.anzctr.org.au/ as ACTRN12613000772741.

Sustained effects of a protein 'preload' on glycaemia and gastric emptying over 4 weeks in patients with type 2 diabetes: A randomized clinical trial

We have shown that the capacity of 25g whey preloads to slow gastric emptying and reduce postprandial glycaemia persists after 4 weeks regular exposure in patients with diet-controlled type 2 diabetes. This dietary strategy therefore appears feasible for larger clinical trials to evaluate beneficial effects on long-term glycaemic control. Registered with the Australian New Zealand Clinical Trials Registry: ACTRN12614000831684.

A systematic review of vascular and endothelial function: effects of fruit, vegetable and potassium intake

AIM

To review the relationships between: 1) Potassium and endothelial function; 2) Fruits and vegetables and endothelial function; 3) Potassium and other measures of vascular function; 4) Fruits and vegetables and other measures of vascular function.

DATA SYNTHESIS

An electronic search for intervention trials investigating the effect of potassium, fruits and vegetables on vascular function was performed in MEDLINE, EMBASE and the Cochrane Library. Potassium appears to improve endothelial function with a dose of >40 mmol/d, however the mechanisms for this effect remain unclear. Potassium may improve measures of vascular function however this effect may be dependent on the effect of potassium on blood pressure. The effect of fruit and vegetables on endothelial function independent of confounding variables is less clear. Increased fruit and vegetable intake may improve vascular function only in high risk populations.

CONCLUSION

Increasing dietary potassium appears to improve vascular function but the effect of increasing fruit and vegetable intake per se on vascular function is less clear.

Dietary quality in people with type 1 and type 2 diabetes compared to age, sex and BMI matched controls

A case-control analysis involving 98 individuals with diabetes and 98 age, sex and BMI matched controls was conducted to determine dietary quality and adherence to dietary recommendations. Diet quality was comparable and intake of fat, saturated fat, fibre, fruit and vegetables did not meet recommendations in both groups.

Dairy consumption and insulin sensitivity: a systematic review of short- and long-term intervention studies

AIM

Evidence from epidemiological studies suggests that higher consumption of dairy products may be inversely associated with risk of type 2 diabetes and other components of the metabolic syndrome, although the evidence is mixed. Intervention studies that increase dairy intake often involve lifestyle changes, including weight loss, which alone will improve insulin sensitivity. The aim of this review was to examine weight stable intervention studies that assess the effect of an increased intake of dairy products or dairy derived supplements on glucose metabolism and insulin sensitivity.

DATA SYNTHESIS

An electronic search was conducted using MEDLINE, EMBASE, the Cochrane Database and Web of Science for randomised controlled trials altering only dairy intake in humans with no other lifestyle or dietary change, particularly no weight change, and with measurement of glucose or insulin. Healthy participants and those with features of the metabolic syndrome were included. Chronic whey protein supplementation was also included. Ten studies were included in this systematic review.

CONCLUSIONS

In adults, four of the dairy interventions showed a positive effect on insulin sensitivity as assessed by Homeostasis Model Assessment (HOMA); one was negative and five had no effect. As the number of weight stable intervention studies is very limited and participant numbers small, these findings need to be confirmed by larger trials in order to conclusively determine any relationship between dairy intake and insulin sensitivity.

Dietary predictors of arterial stiffness in a cohort with type 1 and type 2 diabetes

OBJECTIVE

To determine the dietary predictors of central blood pressure, augmentation index and pulse wave velocity (PWV) in subjects with type 1 and type 2 diabetes.

METHODS

Participants were diagnosed with type 1 or type 2 diabetes and had PWV and/or pulse wave analysis performed. Dietary intake was measured using the Dietary Questionnaire for Epidemiological Studies Version 2 Food Frequency Questionnaire. Serum lipid species and carotenoids were measured, using liquid chromatography electrospray ionization-tandem mass spectrometry and high performance liquid chromatography, as biomarkers of dairy and vegetable intake, respectively. Associations were determined using linear regression adjusted for potential confounders.

RESULTS

PWV (n = 95) was inversely associated with reduced fat dairy intake (β = -0.01; 95% CI -0.02, -0.01; p = 0 < 0.05) in particular yoghurt consumption (β = -0.04; 95% CI -0.09, -0.01; p = 0 < 0.05) after multivariate adjustment. Total vegetable consumption was negatively associated with PWV in the whole cohort after full adjustment (β = -0.04; 95% CI -0.07, -0.01; p < 0.05). Individual lipid species, particularly those containing 14:0, 15:0, 16:0, 17:0 and 17:1 fatty acids, known to be of ruminant origin, in lysophosphatidylcholine, cholesterol ester, diacylglycerol, phosphatidylcholine, sphingomyelin and triacylglycerol classes were positively associated with intake of full fat dairy, after adjustment for multiple comparisons. However, there was no association between serum lipid species and PWV. There were no dietary predictors of central blood pressure or augmentation index after multivariate adjustment.

CONCLUSION

In this cohort of subjects with diabetes reduced fat dairy intake and vegetable consumption were inversely associated with PWV. The lack of a relationship between serum lipid species and PWV suggests that the fatty acid composition of dairy may not explain the beneficial effect.

Abstract 464: Effects of Increased Potassium and Sodium on Endothelial Function: A Pilot Study

Background and aim: Increased potassium intake has been related to reduced blood pressure (BP) and improved endothelial function. High sodium intake increases BP and impairs endothelial function. The effect of increasing potassium in the presence of high dietary sodium is not known. The aim was to determine the effect of increased potassium and increased sodium on post prandial endothelial function, as assessed by flow mediated dilatation (FMD).

Materials and methods: Eighteen healthy, normotensive volunteers (age 41±16 and BMI 23.0±2.7) received a meal with 3.1mmol potassium and 65mmol sodium (LKHNa), a meal with 38mmol potassium and 65mmol sodium (HKHNa) and a control meal (LKLNa) with 5.5mmol sodium and 3.1mmol potassium on three separate occasions in a randomized order. FMD, pulse wave velocity (PWV), augmentation index (AI) and BP were measured while participants were fasting and at 30, 60, 90 and 120 minutes after the meal.

Results: The LKHNa meal produced a significant reduction in FMD at 90 minutes when compared to the LKLNa control meal (p<0.01). The addition of potassium (HKHNa) significantly attenuated the post meal decrease in FMD when compared to the high sodium meal (p<0.05) at 90 minutes (Figure 1) . There was no significant differences in PWV, AI, or BP. The study will continue until n=40.

Conclusions: The addition of potassium to a high sodium meal may attenuate the post meal reduction in endothelial function as assessed by FMD. Increases in sodium and potassium do not appear to effect PWV, AI or BP in the postprandial state. Additional data collection will continue to elucidate the effect of increased potassium in the presence of high sodium.

Effect of high potassium diet on endothelial function

BACKGROUND AND AIMS

Increased potassium intake is related to reduced blood pressure (BP) and reduced stroke rate. The effect of increased dietary potassium on endothelial function remains unknown. The aim was to determine the effect of increased dietary potassium from fruit and vegetables on endothelial function.

METHODS AND RESULTS

Thirty five healthy men and women (age 32 ± 12 y) successfully completed a randomised cross-over study of 2 × 6 day diets either high or low in potassium. Flow mediated dilatation (FMD), BP, pulse wave velocity (PWV), augmentation index (AI) and a fasting blood sample for analysis of Intercellular Adhesion Molecule-1 (ICAM-1), E-selectin, asymmetric dimethylarginine (ADMA) and endothelin-1 were taken on completion of each intervention. Dietary change was achieved by including bananas and potatoes in the high potassium and apples and rice/pasta in the low potassium diet. Dietary adherence was assessed using 6 day weighed food diaries and a 24 h urine sample. The difference in potassium excretion between the two diets was 48 ± 32 mmol/d (P = 0.000). Fasting FMD was significantly improved by 0.6% ± 1.5% following the high compared to the low potassium diet (P = 0.03). There were no significant differences in BP, PWV, AI, ICAM-1, ADMA or endothelin-1 between the interventions. There was a significant reduction in E-selectin following the high (Median = 5.96 ng/ml) vs the low potassium diet (Median = 6.24 ng/ml), z = -2.49, P = 0.013.

CONCLUSION

Increased dietary potassium from fruit and vegetables improves FMD within 1 week in healthy men and women but the mechanisms for this effect remain unclear.

CLINICAL TRIAL REGISTRY

ACTRN12612000822886.

Abstract 463: Dietary Intake and Arterial Compliance in a Cohort of People with Type 1 and Type 2 Diabetes

Background: Diabetes is associated with a higher risk of cardiovascular disease (CVD) and diet is a modifiable risk factor. However, few studies have examined the association between dietary intake and measures of arterial compliance, a well-established predictor of CVD, in people with diabetes. The aim was to investigate the relationship between dietary intake, augmentation index (AI), and pulse wave velocity (PWV) in a cohort of people with type 1 and type 2 diabetes.

Methods: Participants were adults with type 1 or type 2 diabetes who completed the Dietary Questionnaire for Epidemiological Studies (v2) Food Frequency Questionnaire and had carotid- femoral PWV (n=95) and/or AI (n=110) measured using a SphygmoCor ® XCEL (Sydney, Australia). A random spot urine sample was provided and predicted 24 hour urinary sodium excretion was calculated using the Kawasaki equation.

Results: A negative linear relationship was observed between tertile of dairy intake and PWV which persisted after multivariate adjustment (demographic variables and cardiovascular risk factors) (t=-2.4; p=0.019). PWV was 0.9m/s (95% CI 0.2 to 1.7m/s) lower in the highest tertile (>434g/d) compared to the lowest tertile (<260g/d) of dairy consumption (p=0.02 after multivariate adjustment). There was also a negative linear relationship between AI and tertile of fibre intake (t=-2.6; p=0.012) and tertile of potassium intake (t=-2.4; p=0.019), after multivariate adjustment. Predicted 24hr sodium excretion was positively associated with AI (t=2.2; p=0.029) after adjustment. The lowest tertile of sodium excretion (<69mmol/d) was associated with a 4.7% lower AI compared with the high tertile (>90mmol/d) (p=0.02 after multivariate adjustment). It was estimated that a 100mmol increase in sodium excretion would result in an 8.2% increase in AI.

Conclusion: A dietary pattern that is high in dairy, fibre, and potassium and lower in sodium may improve arterial compliance in people with diabetes.

Attitudes and beliefs of health risks associated with sodium intake in diabetes

BACKGROUND

  Despite good evidence that reducing sodium intake can reduce blood pressure (BP), salt intake in people with type 1 diabetes (T1DM) or type 2 diabetes (T2DM) remains high. The purpose of this study was to describe the knowledge and beliefs of health risks associated with a high salt diet in adults with diabetes.

METHODS

Men and women with T1DM (n = 27; age 38 ± 16 years) or T2DM (n = 124; age 60 ± 11 years) were recruited.

RESULTS

Nine (6.0%) respondents knew the correct maximum daily recommended upper limit for salt intake. Thirty-six (23.9%) participants were not concerned with the amount of salt in their diet. Most participants knew that a diet high in salt was related to high BP (88.1%) and stroke (78.1%) and that foods such as pizza (80.8%) and bacon (84.8%) were high in salt. Fewer than 30% of people knew that foods such as white bread, cheese and breakfast cereals are high in salt (white bread 28.5%, cheese 29.1%, breakfast cereals 19.9%) and 51.0% correctly ranked three different nutrition information panels based on the sodium content. Label reading and purchase of low salt products was used by 60-80% of the group. Estimated average 24 hour urinary sodium excretion was 169 ± 32 mmol/24 h in men and 115 ± 27 mmol/24 h in women.

CONCLUSION

Label reading and purchase of low salt products was used by the majority of the group but their salt excretion was still high. Men who used label reading had a lower salt intake. Other strategies to promote a lower sodium intake such as reducing sodium in staple foods such as bread need investigation.

Effects of intermittent compared to continuous energy restriction on short-term weight loss and long-term weight loss maintenance

Effective strategies are needed to help individuals lose weight and maintain weight loss. The primary aim of this study was to investigate the effect of intermittent energy restriction (IER) compared to continuous energy restriction (CER) on weight loss after 8 weeks and weight loss maintenance after 12 months. Secondary aims were to determine changes in waist and hip measurements and diet quality. In a randomized parallel study, overweight and obese (body mass index [BMI] ≥ 27 kg m(-2)) women were stratified by age and BMI before randomization. Participants undertook an 8-week intensive period with weight, waist and hip circumference measured every 2 weeks, followed by 44 weeks of independent dieting. A food frequency questionnaire was completed at baseline and 12 months, from which diet quality was determined. Weight loss was not significantly different between the two groups at 8 weeks (-3.2 ± 2.1 kg CER, n = 20, -2.0 ± 1.9 kg IER, n = 25; P = 0.06) or at 12 months (-4.2 ± 5.6 kg CER, n = 17 -2.1 ± 3.8 kg IER, n = 19; P = 0.19). Weight loss between 8 and 52 weeks was -0.7 ± 49 kg CER vs. -1 ± 1.1 kg IER; P = 0.6. Waist and hip circumference decreased significantly with time (P < 0.01), with no difference between groups. There was an increase in the Healthy Eating Index at 12 months in the CER compared with the IER group (CER 8.4 ± 9.1 vs. IER -0.3 ± 8.4, P = 0.006). This study indicates that intermittent dieting was as effective as continuous dieting over 8 weeks and for weight loss maintenance at 12 months. This may be useful for individuals who find CER too difficult to maintain.

The association between carotid intima media thickness and individual dietary components and patterns

AIMS

To review: 1) the correlation between individual dietary components and carotid intima media thickness (cIMT); 2) the relationship between dietary patterns and cIMT; 3) the effect of dietary interventions on cIMT progression.

DATA SYNTHESIS

An electronic search for epidemiological and intervention trials investigating the association between dietary components or patterns of intake and cIMT was performed in PUBMED, EMBASE and the Cochrane Library. Epidemiological data shows that a higher intake of fruit, wholegrains and soluble fibre and lower consumption of saturated fat in favour of polyunsaturated fat is associated with lower cIMT. In people at high risk of cardiovascular disease >93 g/day of fruit is associated with lower cIMT. Lower cIMT has also been observed when >0.79 serves/day of wholegrains and >25 g/day of fibre, predominately in the soluble form is consumed. Saturated fat is positively associated with cIMT, for every 10 g/day increase in saturated fat cIMT is 0.03 mm greater. Olive oil is inversely associated with cIMT, with a benefit seen when >34 g/day is consumed. While there are many epidemiological studies exploring the association between dietary intake and cIMT there are few intervention studies. Intervention studies show that a Mediterranean diet may reduce cIMT progression, especially in those with a higher cIMT.

CONCLUSIONS

A Mediterranean style dietary pattern, which is high in fruits, wholegrains, fibre and olive oil and low in saturated fat, may reduce carotid atherosclerosis development and progression. However further research from randomised controlled trials is required to understand the association between diet and cIMT and the underlying mechanisms.

Sodium and potassium excretion are related to bone mineral density in women with coeliac disease

BACKGROUND & AIMS

Women with coeliac disease may have a lower bone mineral density due to the malabsorption of calcium before diagnosis. A high sodium excretion is associated with increased calcium and bone loss. Our aim was to describe the bone mineral density (BMD) and sodium excretion in women with coeliac disease.

METHODS

In a cross-sectional study BMD of the lumbar spine and hip was assessed by dual energy X-ray absorptiometry. Sodium, potassium and calcium excretion were measured from a 24 h urine collection.

RESULTS

In 33 women (51 ± 16 yr) BMD was 1.14 ± 0.19 g/cm(2) and 0.94 ± 0.14 g/cm(2) at the lumbar spine and hip respectively. Age matched Z-scores were -0.1 ± 1.2 and -0.3 ± 1.1 at lumbar spine and hip respectively. Sodium excretion was 107 ± 51 mmol/d; 14 (42%) had a sodium excretion >100 mmol Na/d (145 ± 45 mmol/d). Potassium and calcium excretion were 87 ± 25 mmol/d and 4.1 ± 2.0 mmol/d respectively. In women with Na excretion >100 mmol Na/d, Ca excretion was significantly greater than those with <100 mmol/d (4.9 ± 2.0 vs 3.4 ± 1.8, p < 0.05). Sodium excretion and BMI were positively correlated (r = 0.61, p < 0.001) as were sodium and calcium excretion (r = 0.43, p < 0.05). Sodium excretion was inversely related to femoral neck BMD (t = -2.4 p = 0.023) after adjustment for weight, age, years since diagnosis and potassium excretion. Weight, but no other variable, was a predictor of BMD at the lumbar spine (t = 2.58 p = 0.018).

CONCLUSIONS

Sodium excretion was inversely related and potassium excretion positively related to femoral neck density which was similar to age matched women without coeliac disease.

Long term weight maintenance after advice to consume low carbohydrate, higher protein diets--a systematic review and meta analysis

BACKGROUND

Meta analysis of short term trials indicates that a higher protein, lower carbohydrate weight loss diet enhances fat mass loss and limits lean mass loss compared with a normal protein weight loss diet. Whether this benefit persists long term is not clear.

METHODS AND RESULTS

We selected weight loss studies in adults with at least a 12 month follow up in which a higher percentage protein/lower carbohydrate diet was either planned or would be expected for either weight loss or weight maintenance. Studies were selected regardless of the success of the advice but difference in absolute and percentage protein intake at 12 months was used as a moderator in the analysis. Data was analysed using Comprehensive Meta analysis V2 using a random effects analysis. As many as 32 studies with 3492 individuals were analysed with data on fat and lean mass, glucose and insulin from 18 to 22 studies and lipids from 28 studies. A recommendation to consume a lower carbohydrate, higher protein diet in mostly short term intensive interventions with long term follow up was associated with better weight and fat loss but the effect size was small-standardised means of 0.14 and 0.22, p = 0.008 and p < 0.001 respectively (equivalent to 0.4 kg for both). A difference of 5% or greater in percentage protein between diets at 12 mo was associated with a 3 fold greater effect size compared with <5% (p = 0.038) in fat mass (0.9 vs. 0.3 kg). Fasting triglyceride and insulin were also lower with high protein diets with effect sizes of 0.17 and 0.22, p = 0.003 and p = 0.042 respectively. Other lipids and glucose were not different.

CONCLUSION

The short term benefit of higher protein diets appears to persist to a small degree long term. Benefits are greater with better compliance to the diet.

Postprandial effects of potassium supplementation on vascular function and blood pressure: a randomised cross-over study

BACKGROUND AND AIMS

Endothelial dysfunction, as assessed by flow mediated dilatation (FMD) is an early event in atherosclerosis and an independent predictor of cardiovascular events. The effect of potassium supplementation on endothelial function and blood pressure (BP) in the postprandial state is not known. The aim of this study was to assess endothelial function using FMD in healthy volunteers.

METHODS AND RESULTS

Thirty-two normotensive volunteers received a meal with 36 mmol potassium (High K) and a control 6 mmol potassium (Low K) meal on 2 separate occasions in a randomized order. FMD and BP were measured while participants were fasting and at 30, 60, 90 and 120 min after the meal. There was a postprandial decrease in FMD in both groups. FMD decreased overall less after the High K meal compared to the Low K meal (meal effect p < 0.05). Both meals produced a postprandial decrease in BP at 30 min which returned to baseline levels by 120 min. No significant differences in BP were observed between meals. FMD and systolic BP were negatively correlated at 90 (r = -0.54-0.55, p < 0.01) and 120 min (r = -0.42-0.56, p < 0.01) after both meals.

CONCLUSIONS

A high potassium meal, which contains a similar amount of potassium as 2.5 serves of bananas, can lessen the postprandial reduction in brachial artery FMD when compared to a low potassium meal.