The effect of a plant-based low-carbohydrate ("Eco-Atkins") diet on body weight and blood lipid concentrations in hyperlipidemic subjects

Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis

BACKGROUND

Some popular weight loss diets restricting carbohydrates (CHO) claim to be more effective, and have additional health benefits in preventing cardiovascular disease compared to balanced weight loss diets.

METHODS AND FINDINGS

We compared the effects of low CHO and isoenergetic balanced weight loss diets in overweight and obese adults assessed in randomised controlled trials (minimum follow-up of 12 weeks), and summarised the effects on weight, as well as cardiovascular and diabetes risk. Dietary criteria were derived from existing macronutrient recommendations. We searched Medline, EMBASE and CENTRAL (19 March 2014). Analysis was stratified by outcomes at 3-6 months and 1-2 years, and participants with diabetes were analysed separately. We evaluated dietary adherence and used GRADE to assess the quality of evidence. We calculated mean differences (MD) and performed random-effects meta-analysis. Nineteen trials were included (n = 3209); 3 had adequate allocation concealment. In non-diabetic participants, our analysis showed little or no difference in mean weight loss in the two groups at 3-6 months (MD 0.74 kg, 95%CI -1.49 to 0.01 kg; I2 = 53%; n = 1745, 14 trials; moderate quality evidence) and 1-2 years (MD 0.48 kg, 95%CI -1.44 kg to 0.49 kg; I2 = 12%; n = 1025; 7 trials, moderate quality evidence). Furthermore, little or no difference was detected at 3-6 months and 1-2 years for blood pressure, LDL, HDL and total cholesterol, triglycerides and fasting blood glucose (>914 participants). In diabetic participants, findings showed a similar pattern.

CONCLUSIONS

Trials show weight loss in the short-term irrespective of whether the diet is low CHO or balanced. There is probably little or no difference in weight loss and changes in cardiovascular risk factors up to two years of follow-up when overweight and obese adults, with or without type 2 diabetes, are randomised to low CHO diets and isoenergetic balanced weight loss diets.

Gut microbiota and cardiometabolic outcomes: influence of dietary patterns and their associated components

Many dietary patterns have been associated with cardiometabolic risk reduction. A commonality between these dietary patterns is the emphasis on plant-based foods. Studies in individuals who consume vegetarian and vegan diets have shown a reduced risk of cardiovascular events and incidence of diabetes. Plant-based dietary patterns may promote a more favorable gut microbial profile. Such diets are high in dietary fiber and fermentable substrate (ie, nondigestible or undigested carbohydrates), which are sources of metabolic fuel for gut microbial fermentation and, in turn, result in end products that may be used by the host (eg, short-chain fatty acids). These end products may have direct or indirect effects on modulating the health of their host. Modulation of the gut microbiota is an area of growing interest, and it has been suggested to have the potential to reduce risk factors associated with chronic diseases. Examples of dietary components that alter the gut microbial composition include prebiotics and resistant starches. Emerging evidence also suggests a potential link between interindividual differences in the gut microbiota and variations in physiology or predisposition to certain chronic disease risk factors. Alterations in the gut microbiota may also stimulate certain populations and may assist in biotransformation of bioactive components found in plant foods. Strategies to modify microbial communities may therefore provide a novel approach in the treatment and management of chronic diseases.

Initial investigation of dietitian perception of plant-based protein quality

Interest in plant-based diets is increasing, evidenced by scientific and regulatory recommendations, including Dietary Guidelines for Americans. Dietitians provide guidance in dietary protein selection but little is known about how familiar dietitians are with the quality of plant versus animal proteins or methods for measuring protein quality. Likewise, there is a need to explore their beliefs related to dietary recommendations. The aim of this study was to assess dietitians' perceptions of plant-based protein quality and to determine if these are affected by demographic factors such as age and dietary practice group (DPG) membership. This was a cross-sectional design using an online survey. The survey was sent to all members of the Missouri Dietetic Association. All completed surveys (136) were analyzed. The main outcome measures were responses to belief and knowledge questions about the protein quality of plant-based diets, along with demographic information including age and DPG membership. Descriptive statistics and frequencies were determined, and chi-square analysis was used to determine the associations between belief and knowledge responses and demographic characteristics. Responses to belief statements suggested a high level of support for plant-based diets. No associations were found between any of the belief questions and demographic factors. A majority of respondents were not familiar with protein quality determination methods that are currently recognized by global regulatory and advisory agencies. Potential barriers identified in shifting to a more plant-based diet were lack of interest and perceived difficulty. Knowledge among dietitians of plant-based protein quality in general, and methods of protein quality measurement more specifically, needs to be addressed to enhance their knowledge base for making dietary protein recommendations. Two potential avenues for training are university curricula and continuing education opportunities provided to practitioners who provide dietary advice.

Vegetarian diets in the Adventist Health Study 2: a review of initial published findings

The Adventist Health Study 2 is a large cohort that is well suited to the study of the relation of vegetarian dietary patterns to health and disease risk. Here we review initial published findings with regard to vegetarian diets and several health outcomes. Vegetarian dietary patterns were associated with lower body mass index, lower prevalence and incidence of diabetes mellitus, lower prevalence of the metabolic syndrome and its component factors, lower prevalence of hypertension, lower all-cause mortality, and in some instances, lower risk of cancer. Findings with regard to factors related to vegetarian diets and bone health are also reviewed. These initial results show important links between vegetarian dietary patterns and improved health.

Inclusion of red meat in healthful dietary patterns

Dietary patterns are an important concept in dietary recommendations. The Western pattern is most commonly defined as a diet characterized by high intakes of refined grains, sugar and red meat, and has been shown to be associated with increased risks for certain types of cancer, coronary heart disease, diabetes, and obesity. However, isolating the independent effects of individual foods on health outcomes is central to helping individuals choose foods to build healthier dietary patterns to which they can adhere. Red meat is a popular source of high quality protein and provides a variety of essential nutrients that improve overall diet quality. It is also a source of saturated fatty acids, which observational evidence suggests are associated with heart disease, although recent data challenge this. Several studies have shown that lean red meat can be successfully included in recommended heart-healthy dietary patterns without detriment to blood lipids. Furthermore, increased dietary protein has been shown to promote healthy body weight and composition, in part by increasing satiety, and to improve vitality and stamina.

Social and behavioral risk marker clustering associated with biological risk factors for coronary heart disease: NHANES 2001-2004

BACKGROUND

Social and behavioral risk markers (e.g., physical activity, diet, smoking, and socioeconomic position) cluster; however, little is known whether clustering is associated with coronary heart disease (CHD) risk. Objectives were to determine if sociobehavioral clustering is associated with biological CHD risk factors (total cholesterol, HDL cholesterol, systolic blood pressure, body mass index, waist circumference, and diabetes) and whether associations are independent of individual clustering components.

METHODS

Participants included 4,305 males and 4,673 females aged ≥ 20 years from NHANES 2001-2004. Sociobehavioral Risk Marker Index (SRI) included a summary score of physical activity, fruit/vegetable consumption, smoking, and educational attainment. Regression analyses evaluated associations of SRI with aforementioned biological CHD risk factors. Receiver operator curve analyses assessed independent predictive ability of SRI.

RESULTS

Healthful clustering (SRI = 0) was associated with improved biological CHD risk factor levels in 5 of 6 risk factors in females and 2 of 6 risk factors in males. Adding SRI to models containing age, race, and individual SRI components did not improve C-statistics.

CONCLUSIONS

Findings suggest that healthful sociobehavioral risk marker clustering is associated with favorable CHD risk factor levels, particularly in females. These findings should inform social ecological interventions that consider health impacts of addressing social and behavioral risk factors.

Effect of a 6-month vegan low-carbohydrate ('Eco-Atkins') diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: a randomised controlled trial

OBJECTIVE

Low-carbohydrate diets may be useful for weight loss. Diets high in vegetable proteins and oils may reduce the risk of coronary heart disease. The main objective was to determine the longer term effect of a diet that was both low-carbohydrate and plant-based on weight loss and low-density lipoprotein cholesterol (LDL-C).

DESIGN, SETTING, PARTICIPANTS

A parallel design study of 39 overweight hyperlipidaemic men and postmenopausal women conducted at a Canadian university-affiliated hospital nutrition research centre from April 2005 to November 2006.

INTERVENTION

Participants were advised to consume either a low-carbohydrate vegan diet or a high-carbohydrate lacto-ovo vegetarian diet for 6 months after completing 1-month metabolic (all foods provided) versions of these diets. The prescribed macronutrient intakes for the low-carbohydrate and high-carbohydrate diets were: 26% and 58% of energy from carbohydrate, 31% and 16% from protein and 43% and 25% from fat, respectively.

PRIMARY OUTCOME

Change in body weight.

RESULTS

23 participants (50% test, 68% control) completed the 6-month ad libitum study. The approximate 4 kg weight loss on the metabolic study was increased to -6.9 kg on low-carbohydrate and -5.8 kg on high-carbohydrate 6-month ad libitum treatments (treatment difference (95% CI) -1.1 kg (-2.1 to 0.0), p=0.047). The relative LDL-C and triglyceride reductions were also greater on the low-carbohydrate treatment (treatment difference (95% CI) -0.49 mmol/L (-0.70 to -0.28), p<0.001 and -0.34 mmol/L (-0.57 to -0.11), p=0.005, respectively), as were the total cholesterol:HDL-C and apolipoprotein B:A1 ratios (-0.57 (-0.83, -0.32), p<0.001 and -0.05 (-0.09, -0.02), p=0.003, respectively).

CONCLUSIONS

A self-selected low-carbohydrate vegan diet, containing increased protein and fat from gluten and soy products, nuts and vegetable oils, had lipid lowering advantages over a high-carbohydrate, low-fat weight loss diet, thus improving heart disease risk factors.

TRIAL REGISTRATION

clinicaltrials.gov (http://www.clinicaltrials.gov/), #NCT00256516.

A high-fibre bean-rich diet versus a low-carbohydrate diet for obesity

BACKGROUND

High-fibre and low-carbohydrate diets may enhance satiety and promote weight loss. We compared a diet rich in beans aiming to increase dietary fibre and promote weight loss with a low-carbohydrate diet in a randomised controlled trial to assess effect and tolerability of the high-fibre bean-rich diet.

METHODS AND RESULTS

One hundred and seventy-three women and men, with a mean body mass index of approximately 36 kg m(-2) (one-fifth with diabetes type 2) were randomised to a high-fibre bean-rich diet that achieved mean (SD) fibre intakes of 35.5 (18.6) g day(-1) for women and 42.5 (30.3) g day(-1) for men, or a low-carbohydrate diet. Both diets were induced gradually over 4 weeks and included a 3-day feeding phase. Among 123 (71.1%) completers at 16 weeks, mean (SD) weight loss was 4.1 (4.0) kg in the high-fibre versus 5.2 (4.5) kg in the low-carbohydrate group [difference, 1.1 kg, 95% confidence interval (CI) = -2.6 to -0.5; P = 0.2], with results similar to the intent-to-treat population. Low-density lipoprotein (LDL)-cholesterol levels decreased with the high-fibre diet (difference in LDL-cholesterol versus low-carbohydrate diet, 0.2 mmol L(-1) , 95% CI = 0.01-0.44 mmol L(-1) ; P = 0.045), as did total cholesterol (P = 0.038), whereas changes in other lipids and glucose did not differ. After 52 weeks, the low-carbohydrate (n = 24) group tended to retain weight loss better than the high-fibre group (P = 0.06), although total cholesterol remained lower with the bean-rich diet (P = 0.049).

CONCLUSIONS

A high-fibre bean-rich diet was as effective as a low-carbohydrate diet for weight loss, although only the bean-rich diet lowered atherogenic lipids.

Effects of diet supplementation with Camu-camu (Myrciaria dubia HBK McVaugh) fruit in a rat model of diet-induced obesity

Amazonian Camu-camu fruit (Myrciaria dubia HBK Mc Vaugh) has attracted interest from food and cosmetics industries because of its rich content of vitamin C, flavonoids and anthocyanins. The goal of this study was investigates the antiobesity action of the ingestion of the Camu-camu pulp in a rat model of diet-induced obesity. Wistar rats with obesity induced by subcutaneous injection of monosodium glutamate receiving diet ad libitum. The rats were divided in two groups: an experimental group that ingested 25 mL/day of Camu-camu pulp (CCG) and a non treated group (CG). After 12 weeks, the animals were sacrificed. Blood, liver, heart, white adipose tissues were collected and weighted, biochemical and inflammatory profiles were determinate as well. Animals that received the pulp of Camu-camu reduced their weights of the fat in white adipose tissues, glucose, total cholesterol, triglycerides, LDL-c and insulin blood levels. There was an increase in HDL-c levels. No change was observed in inflammatory markers and liver enzymes. Camu-camu pulp was able to improve the biochemical profile of obesity in rats suggesting that this Amazonian fruit can be further used such a functional food ingredient in control of chronic diseases linked to obesity.

Kimchi, a fermented vegetable, improves serum lipid profiles in healthy young adults: randomized clinical trial

Vegetable-based diets have generally focused on their health benefits including negative associations with the serum cholesterol concentrations. The aim of this study was to investigate whether serum lipid concentrations are influenced by the amount of kimchi intake. For the study, 100 volunteers were assigned to 2 dietary groups, low (15 g/day, n=50) and high (210 g/day, n=50) kimchi intake, and were housed together in a dormitory for 7 days. Identical meals except with different amount of kimchi were provided and subjects were instructed to maintain their normal physical activity. Concentrations of fasting blood glucose (FBG), total glucose, total cholesterol and low density lipoprotein (LDL)-C significantly decreased in both groups after 7 days of kimchi intake, but the effects were dose dependent. Lipid lowering effects of kimchi were more profound in the subjects with total cholesterol and LDL-C level over 190 and 130 mg/dL, respectively, in both groups. FBG was significantly decreased in the high kimchi intake as compared to the low intake group (P=.003). In conclusion, greater consumption of kimchi improved FBG and serum total cholesterol in young healthy adults.

Alternate day fasting (ADF) with a high-fat diet produces similar weight loss and cardio-protection as ADF with a low-fat diet

Alternate day fasting (ADF) with a low-fat (LF) diet is effective for weight loss and cardio-protection. However, the applicability of these findings is questionable as the majority of Americans consume a high-fat (HF) diet.

OBJECTIVE

The goal of this study was to determine if these beneficial changes in body weight and coronary heart disease (CHD) risk can be reproduced if an HF background diet is used in place of an LF diet during ADF.

METHODS

Thirty-two obese subjects were randomized to an ADF-HF (45% fat) or ADF-LF diet (25% fat), which consisted of two phases: 1) a 2-week baseline weight maintenance period, and 2) an 8-week ADF weight loss period. All food was provided during the study.

RESULTS

Body weight was reduced (P<0.0001) by ADF-HF (4.8%±1.1%) and by ADF-LF (4.2%±0.8%). Fat mass decreased (P<0.0001) by ADF-HF (5.4±1.5 kg) and ADF-LF (4.2±0.6 kg). Fat free mass remained unchanged. Waist circumference decreased (P<0.001) by ADF-HF (7.2±1.5 cm) and ADF-LF (7.3±0.9 cm). LDL cholesterol and triacylglycerol concentrations were reduced (P<0.001) by both interventions (ADF-HF: 18.3%±4.6%, 13.7%±4.8%; and ADF-LF: 24.8%±2.6%, 14.3%±4.4%). HDL cholesterol, blood pressure, and heart rate remained unchanged. There were no between-group differences for any parameter.

CONCLUSION

These findings suggest that an ADF-HF diet is equally as effective as an ADF-LF diet in helping obese subjects lose weight and improve CHD risk factors.

Food combinations for cholesterol lowering

Reducing elevated LDL-cholesterol is a key public health challenge. There is substantial evidence from randomised controlled trials (RCT) that a number of foods and food components can significantly reduce LDL-cholesterol. Data from RCT have been reviewed to determine whether effects are additive when two or more of these components are consumed together. Typically components, such as plant stanols and sterols, soya protein, β-glucans and tree nuts, when consumed individually at their target rate, reduce LDL-cholesterol by 3-9 %. Improved dietary fat quality, achieved by replacing SFA with unsaturated fat, reduces LDL-cholesterol and can increase HDL-cholesterol, further improving blood lipid profile. It appears that the effect of combining these interventions is largely additive; however, compliance with multiple changes may reduce over time. Food combinations used in ten 'portfolio diet' studies have been reviewed. In clinical efficacy studies of about 1 month where all foods were provided, LDL-cholesterol is reduced by 22-30 %, whereas in community-based studies of >6 months' duration, where dietary advice is the basis of the intervention, reduction in LDL-cholesterol is about 15 %. Inclusion of MUFA into 'portfolio diets' increases HDL-cholesterol, in addition to LDL-cholesterol effects. Compliance with some of these dietary changes can be achieved more easily compared with others. By careful food component selection, appropriate to the individual, the effect of including only two components in the diet with good compliance could be a sustainable 10 % reduction in LDL-cholesterol; this is sufficient to make a substantial impact on cholesterol management and reduce the need for pharmaceutical intervention.

A symposium and workshop report from the Global Nutrition and Epidemiologic Transition Initiative: nutrition transition and the global burden of type 2 diabetes

The present report summarises the symposium ‘Nutrition Transition and the Global Burden of Type 2 Diabetes’ and a workshop on strategies for dietary interventions to prevent type 2 diabetes held by the Global Nutrition and Epidemiologic Transition Initiative, Boston, MA, USA in November 2011. The objectives of this event were to bring attention to the global epidemic of type 2 diabetes in light of the ongoing nutrition transition worldwide, especially in low- and middle-income countries, and to highlight the present evidence on key dietary risk factors contributing to the global diabetes burden. The meeting put forward ideas for further research on this topic and discussed practical recommendations to design and implement culturally appropriate dietary interventions with a focus on improving carbohydrate quality to help alleviate this growing health problem.

Egg yolk consumption and carotid plaque

BACKGROUND

Increasingly the potential harm from high cholesterol intake, and specifically from egg yolks, is considered insignificant. We therefore assessed total plaque area (TPA) in patients attending Canadian vascular prevention clinics to determine if the atherosclerosis burden, as a marker of arterial damage, was related to egg intake. To provide perspective on the magnitude of the effect, we also analysed the effect of smoking (pack-years).

METHODS

Consecutive patients attending vascular prevention clinics at University Hospital had baseline measurement of TPA by duplex ultrasound, and filled out questionnaires regarding their lifestyle and medications, including pack-years of smoking, and the number of egg yolks consumed per week times the number of years consumed (egg-yolk years).

RESULTS

Data were available in 1262 patients; mean (SD) age was 61.5 (14.8) years; 47% were women. Carotid plaque area increased linearly with age after age 40, but increased exponentially with pack-years of smoking and with egg-yolk years. Plaque area in patients consuming <2 eggs per week (n = 388) was 125 ± 129 mm(2), versus 132 ± 142 mm(2) in those consuming 3 or more eggs per week (n = 603); (p < 0.0001 after adjustment for age). In multiple regression, egg-yolk years remained significant after adjusting for coronary risk factors.

INTERPRETATION

Our findings suggest that regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease. This hypothesis should be tested in a prospective study with more detailed information about diet, and other possible confounders such as exercise and waist circumference.

Dyslipidemia Management for Secondary Prevention in Women with Cardiovascular Disease: What Can We Expect From Non-pharmacologic Strategies?

Cardiovascular disease is the leading cause of death in women and the treatment of dyslipidemia is a cornerstone of secondary prevention. Pharmacologic therapy with statins can lower LDL-C by 30-50% and reduce the risk of recurrent coronary heart disease in both men and women. While significant reductions in LDL-C can be achieved with statin therapy, diet and lifestyle modification remain an essential part of the treatment regimen for cardiovascular disease. Moreover, a large proportion of the U.S. population is sedentary, overweight, and does not consume a heart-healthy diet. Non-pharmacologic treatment strategies also improve other cardiovascular risk factors and are generally easily accessible. In this review, we examine the effect of non-pharmacologic therapy on lipids as part of the secondary prevention strategy of cardiovascular disease in women.

Effects of sleep restriction on glucose control and insulin secretion during diet-induced weight loss

Insufficient sleep is associated with changes in glucose tolerance, insulin secretion, and insulin action. Despite widespread use of weight-loss diets for metabolic risk reduction, the effects of insufficient sleep on glucose regulation in overweight dieters are not known. To examine the consequences of recurrent sleep restriction on 24-h blood glucose control during diet-induced weight loss, 10 overweight and obese adults (3F/7M; mean (s.d.) age 41 (5) years; BMI 27.4 (2.0) kg/m(2)) completed two 14-day treatments with hypocaloric diet and 8.5- or 5.5-h nighttime sleep opportunity in random order 7 (3) months apart. Oral and intravenous glucose tolerance test (IVGTT) data, fasting lipids and free fatty acids (FFA), 24-h blood glucose, insulin, C-peptide, and counter-regulatory hormone measurements were collected after each treatment. Participants had comparable weight loss (1.0 (0.3) BMI units) during each treatment. Bedtime restriction reduced sleep by 131 (30) min/day. Recurrent sleep curtailment decreased 24-h serum insulin concentrations (i.e., enhanced 24-h insulin economy) without changes in oral glucose tolerance and 24-h glucose control. This was accompanied by a decline in fasting blood glucose, increased fasting FFA, which suppressed normally following glucose ingestion, and lower total and low-density lipoprotein cholesterol concentrations. Sleep-loss-related changes in counter-regulatory hormone secretion during the IVGTT limited the utility of the test in this study. In conclusion, sleep restriction enhanced 24-h insulin economy without compromising glucose homeostasis in overweight individuals placed on a balanced hypocaloric diet. The changes in fasting blood glucose, insulin, lipid and FFA concentrations in sleep-restricted dieters resembled the pattern of human metabolic adaptation to reduced carbohydrate availability.

Effects of higher- versus lower-protein diets on health outcomes: a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Numerous randomised controlled trials (RCTs) published in first tier medical journals have evaluated the health effects of diets high in protein. We conducted a rigorous systematic review of RCTs comparing higher- and lower-protein diets.

METHODS

We searched several electronic databases up to July 2011 for studies focusing on patient-important outcomes (for example, cardiovascular disease) and secondary outcomes such as risk factors for chronic disease (for example, adiposity).

RESULTS

We identified 111 articles reporting on 74 trials. Pooled effect sizes using standardised mean differences (SMDs) were small to moderate and favoured higher-protein diets for weight loss (SMD -0.36, 95% confidence interval (CI) -0.56 to -0.17), body mass index (-0.37, CI -0.56 to 0.19), waist circumference (-0.43, CI -0.69 to -0.16), blood pressure (systolic: -0.21, CI -0.32 to -0.09 and diastolic: -0.18, CI -0.29 to -0.06), high-density lipoproteins (HDL 0.25, CI 0.07 to 0.44), fasting insulin (-0.20, CI -0.39 to -0.01) and triglycerides (-0.51, CI -0.78 to -0.24). Sensitivity analysis of studies with lower risk of bias abolished the effect on HDL and fasting insulin, and reduced the effect on triglycerides. We observed nonsignificant effects on total cholesterol, low-density lipoproteins, C-reactive protein, HbA1c, fasting blood glucose, and surrogates for bone and kidney health. Adverse gastrointestinal events were more common with high-protein diets. Multivariable meta-regression analysis showed no significant dose response with higher protein intake.

CONCLUSIONS

Higher-protein diets probably improve adiposity, blood pressure and triglyceride levels, but these effects are small and need to be weighed against the potential for harms.

Dietary fat and heart failure: moving from lipotoxicity to lipoprotection

There is growing evidence suggesting that dietary fat intake affects the development and progression of heart failure. Studies in rodents show that in the absence of obesity, replacing refined carbohydrate with fat can attenuate or prevent ventricular expansion and contractile dysfunction in response to hypertension, infarction, or genetic cardiomyopathy. Relatively low intake of n-3 polyunsaturated fatty acids from marine sources alters cardiac membrane phospholipid fatty acid composition, decreases the onset of new heart failure, and slows the progression of established heart failure. This effect is associated with decreased inflammation and improved resistance to mitochondrial permeability transition. High intake of saturated, monounsaturated, or n-6 polyunsaturated fatty acids has also shown beneficial effects in rodent studies. The underlying mechanisms are complex, and a more thorough understanding is needed of the effects on cardiac phospholipids, lipid metabolites, and metabolic flux in the normal and failing heart. In summary, manipulation of dietary fat intake shows promise in the prevention and treatment of heart failure. Clinical studies generally support high intake of n-3 polyunsaturated fatty acids from marine sources to prevent and treat heart failure. Additional clinical and animals studies are needed to determine the optimal diet in terms of saturated, monounsaturated, and n-6 polyunsaturated fatty acids intake for this vulnerable patient population.

Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial

BACKGROUND

Weight loss reduces body fat and lean mass, but whether these changes are influenced by macronutrient composition of the diet is unclear.

OBJECTIVE

We determined whether energy-reduced diets that emphasize fat, protein, or carbohydrate differentially reduce total, visceral, or hepatic fat or preserve lean mass.

DESIGN

In a subset of participants in a randomized trial of 4 weight-loss diets, body fat and lean mass (n = 424; by using dual-energy X-ray absorptiometry) and abdominal and hepatic fat (n = 165; by using computed tomography) were measured after 6 mo and 2 y. Changes from baseline were compared between assigned amounts of protein (25% compared with 15%) and fat (40% compared with 20%) and across 4 carbohydrate amounts (35% through 65%).

RESULTS

At 6 mo, participants lost a mean (±SEM) of 4.2 ± 0.3 kg (12.4%) fat and 2.1 ± 0.3 kg (3.5%) lean mass (both P < 0.0001 compared with baseline values), with no differences between 25% and 15% protein (P ≥ 0.10), 40% and 20% fat (P ≥ 0.34), or 65% and 35% carbohydrate (P ≥ 0.27). Participants lost 2.3 ± 0.2 kg (13.8%) abdominal fat: 1.5 ± 0.2 kg (13.6%) subcutaneous fat and 0.9 ± 0.1 kg (16.1%) visceral fat (all P < 0.0001 compared with baseline values), with no differences between the diets (P ≥ 0.29). Women lost more visceral fat than did men relative to total-body fat loss. Participants regained ~40% of these losses by 2 y, with no differences between diets (P ≥ 0.23). Weight loss reduced hepatic fat, but there were no differences between groups (P ≥ 0.28). Dietary goals were not fully met; self-reported contrasts were closer to 2% protein, 8% fat, and 14% carbohydrate at 6 mo and 1%, 7%, and 10%, respectively, at 2 y.

CONCLUSION

Participants lost more fat than lean mass after consumption of all diets, with no differences in changes in body composition, abdominal fat, or hepatic fat between assigned macronutrient amounts. This trial was registered at clinicaltrials.gov as NCT00072995.

Equol status and blood lipid profile in hyperlipidemia after consumption of diets containing soy foods

BACKGROUND

Recent analyses have challenged the effectiveness of soy foods as part of a cardiovascular risk reduction diet.

OBJECTIVE

The objective of the study was to show whether equol status determines the effectiveness of soy foods to lower LDL cholesterol and to raise HDL cholesterol.

DESIGN

Eighty-five hypercholesterolemic men and postmenopausal women (42 men, 43 women) participated in 1 of 3 studies that represented a range of soy interventions and that followed the same general protocol at a Canadian university hospital research center. Soy foods were provided for 1 mo at doses of 30-52 g/d for the 3 studies as follows: 1) soy foods with either high-normal (73 mg/d) or low (10 mg/d) isoflavones, 2) soy foods with or without a prebiotic to enhance colonic fermentation (10 g polyfructans/d), or 3) soy foods with a low-carbohydrate diet (26% carbohydrate). Studies 1 and 2 were randomized controlled crossover trials, and study 3 was a parallel study.

RESULTS

The separation of the group into equol producers (n = 30) and nonproducers (n = 55) showed similar reductions from baseline in LDL cholesterol (-9.3 ± 2.5% and -11.1 ± 1.6%, respectively; P = 0.834), with preservation of HDL cholesterol and apolipoprotein A-I only in equol producers compared with reductions in nonproducers (HDL cholesterol: +0.9 ± 2.7% compared with -4.3 ± 1.1%, P = 0.006; apolipoprotein A-I: -1.0 ± 1.1% compared with -4.7 ± 1.0%; P = 0.011). The amount of urinary equol excreted did not relate to the changes in blood lipids.

CONCLUSIONS

Soy foods reduced serum LDL cholesterol equally in both equol producers and nonproducers. However, in equol producers, ~35% of our study population, soy consumption had the added cardiovascular benefit of maintaining higher HDL-cholesterol concentrations than those seen in equol nonproducers. This trial was registered at clinicaltrials.gov as NCT00877825 (study 1), NCT00516594 (study 2), and NCT00256516 (study 3).

Protein and coronary heart disease: the role of different protein sources

Meat protein is associated with an increase in risk of heart disease. Recent data have shown that meat protein appeared to be associated with weight gain over 6.5 years, with 1 kg of weight increase per 125 g of meat per day. In the Nurses' Health Study, diets low in red meat, containing nuts, low-fat dairy, poultry, or fish, were associated with a 13% to 30% lower risk of CHD compared with diets high in meat. Low-carbohydrate diets high in animal protein were associated with a 23% higher total mortality rate whereas low-carbohydrate diets high in vegetable protein were associated with a 20% lower total mortality rate. Recent soy interventions have been assessed by the American Heart Association and found to be associated with only small reductions in LDL cholesterol. Although dairy intake has been associated with a lower weight and lower insulin resistance and metabolic syndrome, the only long-term (6 months) dairy intervention performed so far has shown no effects on these parameters.

The effect of increased dietary fruit and vegetable consumption on endothelial activation, inflammation and oxidative stress in hypertensive volunteers

BACKGROUND AND AIMS

Public health campaigns recommend increased fruit and vegetable (FV) consumption as an effective means of cardiovascular risk reduction. During an 8 week randomised control trial among hypertensive volunteers, we noted significant improvements in endothelium-dependent vasodilatation with increasing FV consumption. Circulating indices of inflammation, endothelial activation and insulin resistance are often employed as alternative surrogates for systemic arterial health. The responses of several such biomarkers to our previously described FV intervention are reported here.

METHODS AND RESULTS

Hypertensive volunteers were recruited from medical outpatient clinics. After a common 4 week run-in period during which FV consumption was limited to 1 portion per day, participants were randomised to 1, 3 or 6 portions daily for 8 weeks. Venous blood samples for biomarker analyses were collected during the pre and post-intervention vascular assessments. A total of 117 volunteers completed the 12 week study. Intervention-related changes in circulating levels of high sensitivity C-reactive protein (hsCRP), soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1) did not differ significantly between FV groups. Similarly, there were no significant between group differences of change in homeostasis model assessment (HOMA) scores.

CONCLUSIONS

Despite mediating a significant improvement in acetylcholine induced vasodilatation, increased FV consumption did not affect a calculated measure of insulin resistance or concentrations of the circulating biomarkers measured during this study. Functional indices of arterial health such as endothelium-dependent vasomotion are likely to provide more informative cardiovascular end-points during short-term dietary intervention trials.

Nuts as a replacement for carbohydrates in the diabetic diet

OBJECTIVE

Fat intake, especially monounsaturated fatty acid (MUFA), has been liberalized in diabetic diets to preserve HDL cholesterol and improve glycemic control, yet the exact sources have not been clearly defined. Therefore, we assessed the effect of mixed nut consumption as a source of vegetable fat on serum lipids and HbA(1c) in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 117 type 2 diabetic subjects were randomized to one of three treatments for 3 months. Supplements were provided at 475 kcal per 2,000-kcal diet as mixed nuts (75 g/day), muffins, or half portions of both. The primary outcome was change in HbA(1c).

RESULTS

The relative increase in MUFAs was 8.7% energy on the full-nut dose compared with muffins. Using an intention-to-treat analysis (n = 117), full-nut dose (mean intake 73 g/day) reduced HbA(1c) (-0.21% absolute HbA(1c) units, 95% CI -0.30 to -0.11, P < 0.001) with no change after half-nut dose or muffin. Full-nut dose was significantly different from half-nut dose (P = 0.004) and muffin (P = 0.001), but no difference was seen between half-nut dose and muffins. LDL cholesterol also decreased significantly after full-nut dose compared with muffin. The LDL cholesterol reduction after half-nut dose was intermediate and not significantly different from the other treatments. Apolipoprotein (apo) B and the apoB:apoA1 ratio behaved similarly. Nut intake related negatively to changes in HbA(1c) (r = -0.20, P = 0.033) and LDL cholesterol (r = -0.24, P = 0.011).

CONCLUSIONS

Two ounces of nuts daily as a replacement for carbohydrate foods improved both glycemic control and serum lipids in type 2 diabetes.

Diets of modern hunter-gatherers vary substantially in their carbohydrate content depending on ecoenvironments: results from an ethnographic analysis

In the past, attempts have been made to estimate the carbohydrate contents of preagricultural human diets. Those estimations have primarily been based on interpretations of ethnographic data of modern hunter-gatherers. In this study, it was hypothesized that diets of modern hunter-gatherers vary in their carbohydrate content depending on ecoenvironments. Thus, using data of plant-to-animal subsistence ratios, we calculated the carbohydrate intake (percentage of the total energy) in 229 hunter-gatherer diets throughout the world and determined how differences in ecological environments altered carbohydrate intake. We found a wide range of carbohydrate intake (≈3%-50% of the total energy intake; median and mode, 16%-22% of the total energy). Hunter-gatherer diets were characterized by an identical carbohydrate intake (30%-35% of the total energy) over a wide range of latitude intervals (11°-40° north or south of the equator). However, with increasing latitude intervals from 41° to greater than 60°, carbohydrate intake decreased markedly from approximately equal to 20% to 9% or less of the total energy. Hunter-gatherers living in desert and tropical grasslands consumed the most carbohydrates (≈29%-34% of the total energy). Diets of hunter-gatherers living in northern areas (tundra and northern coniferous forest) contained a very low carbohydrate content (≤15% of the total energy). In conclusion, diets of hunter-gatherers showed substantial variation in their carbohydrate content. Independent of the local environment, however, the range of energy intake from carbohydrates in the diets of most hunter-gatherer societies was markedly different (lower) from the amounts currently recommended for healthy humans.

Comparison of high protein and high fiber weight-loss diets in women with risk factors for the metabolic syndrome: a randomized trial

BACKGROUND

Studies have suggested that moderately high protein diets may be more appropriate than conventional low-fat high carbohydrate diets for individuals at risk of developing the metabolic syndrome and type 2 diabetes. However in most such studies sources of dietary carbohydrate may not have been appropriate and protein intakes may have been excessively high. Thus, in a proof-of-concept study we compared two relatively low-fat weight loss diets - one high in protein and the other high in fiber-rich, minimally processed cereals and legumes - to determine whether a relatively high protein diet has the potential to confer greater benefits.

METHODS

Eighty-three overweight or obese women, 18-65 years, were randomized to either a moderately high protein (30% protein, 40% carbohydrate) diet (HP) or to a high fiber, relatively high carbohydrate (50% carbohydrate, > 35 g total dietary fiber, 20% protein) diet (HFib) for 8 weeks. Energy intakes were reduced by 2000 - 4000 kJ per day in order to achieve weight loss of between 0.5 and 1 kg per week.

RESULTS

Participants on both diets lost weight (HP: -4.5 kg [95% confidence interval (CI):-3.7, -5.4 kg] and HFib: -3.3 kg [95% CI: -4.2, -2.4 kg]), and reduced total body fat (HP: -4.0 kg [5% CI:-4.6, -3.4 kg] and HFib: -2.5 kg [95% CI: -3.5, -1.6 kg]), and waist circumference (HP: -5.4 cm [95% CI: -6.3, -4.5 cm] and HFib: -4.7 cm [95% CI: -5.8, -3.6 cm]), as well as total and LDL cholesterol, triglycerides, fasting plasma glucose and blood pressure. However participants on HP lost more body weight (-1.3 kg [95% CI: -2.5, -0.1 kg; p = 0.039]) and total body fat (-1.3 kg [95% CI: -2.4, -0.1; p = 0.029]). Diastolic blood pressure decreased more on HP (-3.7 mm Hg [95% CI: -6.2, -1.1; p = 0.005]).

CONCLUSIONS

A realistic high protein weight-reducing diet was associated with greater fat loss and lower blood pressure when compared with a high carbohydrate, high fiber diet in high risk overweight and obese women.

Fibroblast growth factor 21 is a metabolic regulator that plays a role in the adaptation to ketosis

Fibroblast growth factor 21 (FGF21) was originally identified as a member of the FGF family in homology studies and is a member of the endocrine FGF subfamily that lacks heparin binding domains and is released into the circulation. A potential role as a metabolic regulator emerged when FGF21 was shown to increase glucose uptake in adipocytes. Subsequently, marked elevations in FGF21 expression were observed in mice that ate a ketogenic diet and when fasting, which suggests that FGF21 expression plays a role in the adaptation to metabolic states that require increased fatty acid oxidation. Consistent with this evidence, FGF21 knockout mice were not able to respond appropriately to consumption of a ketogenic diet. FGF21 expression is downstream of peroxisome proliferator-activated receptor (PPAR) α in the liver and PPARγ in adipose tissue. FGF21 concentrations are higher in both rodent and human obesity, and recent data suggest that obesity may be an FGF21-resistant state. Recent data increasingly suggest that FGF21 is an important metabolic regulator that may have potential clinical implications.

Low-carbohydrate diet scores and risk of type 2 diabetes in men

BACKGROUND

Fat and protein sources may influence whether low-carbohydrate diets are associated with type 2 diabetes (T2D).

OBJECTIVE

The objective was to compare the associations of 3 low-carbohydrate diet scores with incident T2D.

DESIGN

A prospective cohort study was conducted in participants from the Health Professionals Follow-Up Study who were free of T2D, cardiovascular disease, or cancer at baseline (n = 40,475) for up to 20 y. Cumulative averages of 3 low-carbohydrate diet scores (high total protein and fat, high animal protein and fat, and high vegetable protein and fat) were calculated every 4 y from food-frequency questionnaires and were associated with incident T2D by using Cox models.

RESULTS

We documented 2689 cases of T2D during follow-up. After adjustments for age, smoking, physical activity, coffee intake, alcohol intake, family history of T2D, total energy intake, and body mass index, the score for high animal protein and fat was associated with an increased risk of T2D [top compared with bottom quintile; hazard ratio (HR): 1.37; 95% CI: 1.20, 1.58; P for trend < 0.01]. Adjustment for red and processed meat attenuated this association (HR: 1.11; 95% CI: 0.95, 1.30; P for trend = 0.20). A high score for vegetable protein and fat was not significantly associated with the risk of T2D overall but was inversely associated with T2D in men aged <65 y (HR: 0.78; 95% CI: 0.66, 0.92; P for trend = 0.01, P for interaction = 0.01).

CONCLUSIONS

A score representing a low-carbohydrate diet high in animal protein and fat was positively associated with the risk of T2D in men. Low-carbohydrate diets should obtain protein and fat from foods other than red and processed meat.

Changes in body weight and metabolic indexes in overweight breast cancer survivors enrolled in a randomized trial of low-fat vs. reduced carbohydrate diets

Overweight status is common among women breast cancer survivors and places them at greater risk for metabolic disorders, cardiovascular morbidity, and breast cancer recurrence than nonoverweight survivors. Efforts to promote weight control in this population are needed. The objective of this research was to evaluate the effect of low-fat or low-carbohydrate diet counseling on weight loss, body composition, and changes in metabolic indexes in overweight postmenopausal breast cancer survivors. Survivors (n = 40) were randomized to receive dietitian counseling for a low-fat or a reduced carbohydrate diet for 6 mo. Weight and metabolic measures, including glucose, insulin, HbA1c, HOMA, lipids, hsCRP, as well as blood pressure were measured at baseline, 6, 12 and 24 wk. Dietary intake of fat and carbohydrate was reduced by 24 and 76 g/day, respectively. Weight loss averaged 6.1 (± 4.8 kg) at 24 wk and was not significantly different by diet group; loss of lean mass was also demonstrated. All subjects demonstrated improvements in total/HDL cholesterol ratio, and significant reductions in HbA1c, insulin, and HOMA. Triglycerides levels were significantly reduced only in the low-carbohydrate diet group (-31.1 ± 36.6; P = 0.01). Significant improvements in weight and metabolic indexes can be demonstrated among overweight breast cancer survivors adherent to either a carbohydrate- or fat-restricted diet.

Low-fat diets for acquired hypercholesterolaemia

BACKGROUND

Hypercholesterolaemia, characterised by raised blood cholesterol levels, is not a disease itself but a metabolic derangement that often contributes to many diseases, notably cardiovascular disease. In most cases, elevated cholesterol levels are associated with high-fat diet, especially saturated fat, coupled with an inactive lifestyle. Less commonly, raised cholesterol may be related to an inherited disorder, familial hypercholesterolaemia. This systematic review is only concerned with acquired hypercholesterolaemia.

OBJECTIVES

To assess the effects of low-fat diets for acquired hypercholesterolaemia and to investigate the incidence of adverse effects from low-fat dietary interventions. We planned to compare the relative effectiveness of low-fat diets with calorie-restricted diets for acquired hypercholesterolaemia. We also wanted to look into the relative effectiveness of low-fat diets and pharmacological interventions for acquired hypercholesterolaemia.

SEARCH STRATEGY

Studies were obtained from computerised searches of The Cochrane Library, MEDLINE, EMBASE and databases of ongoing trials. Date of last search was February 2010.

SELECTION CRITERIA

Otherwise healthy adults (equal to or greater than 18 years) with acquired (not familial) hypercholesterolaemia. We defined hypercholesterolaemia as either total cholesterol greater than 5.2 mmol/L, LDL-cholesterol greater than 3.0 mmol/L, HDL-cholesterol less than 1.0 mmol/L or a combination thereof, although investigators' definitions were also accepted. We wanted to include any low-fat dietary intervention, like low-fat and low-saturated fat diets, intended to lower serum total and LDL-cholesterol or to raise HDL-cholesterol. A low-fat diet was considered as a fat calorie intake less than 20% of the total calories. The minimum duration of the intervention had to be six months. We excluded studies in unhealthy people.

DATA COLLECTION AND ANALYSIS

Two authors were planned to independently assess risk of bias and extract data.

MAIN RESULTS

No study met our inclusion criteria.

AUTHORS' CONCLUSIONS

Well designed, adequately powered randomised controlled trials investigating patient-relevant outcomes of low-fat diets for otherwise healthy people with hypercholesterolaemia are required.

Plant and animal protein intake and its association with overweight and obesity among the Belgian population

The objective of the present study was to assess animal and plant protein intakes in the Belgian population and to examine their relationship with overweight and obesity (OB). The subjects participated in the Belgian National Food Consumption Survey conducted in 2004. Food consumption was assessed by using two non-consecutive 24 h dietary recalls. About 3083 participants ( ≥ 15 years of age; 1546 males, 1537 females) provided completed dietary information. Animal protein intake (47 g/d) contributed more to total protein intakes of 72 g/d than plant protein intake, which accounted for 25 g/d. Meat and meat products were the main contributors to total animal protein intakes (53 %), whereas cereals and cereal products contributed most to plant protein intake (54 %). Males had higher animal and plant protein intakes than females (P < 0·001). Legume and soya protein intakes were low in the whole population (0·101 and 0·174 g/d, respectively). In males, animal protein intake was positively associated with BMI (β = 0·013; P = 0·001) and waist circumference (WC; β = 0·041; P = 0·002). Both in males and females, plant protein intake was inversely associated with BMI (males: β = − 0·036; P < 0·001; females: β = − 0·046; P = 0·001) and WC (male: β = − 0·137; P < 0·001; female: β = − 0·096; P = 0·024). In conclusion, plant protein intakes were lower than animal protein intakes among a representative sample of the Belgian population and decreased with age. Associations with anthropometric data indicated that plant proteins could offer a protective effect in the prevention of overweight and OB in the Belgian population.

Short term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels

BACKGROUND

The aim of this study was to evaluate short-term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels.

METHODS

Overweight (BMI between 25-30 kg/m2) or obese (BMI over 30 kg/m2) subjects with low HDL-C levels (men with HDL-C <1.03, women <1.29 mmol/l) were invited to the study. A 1400 kcal 75-gram carbohydrate (CHO) diet was given to women and an 1800 kcal 100-gram CHO diet was given to men for four weeks. The distribution of daily energy of the prescribed diet was 21-22% from CHO, 26-29% from protein and 49-53% from fat. Subjects completed a three-day dietary intake record before each visit. Anthropometric indices, body fat ratio, blood lipids, glucose and insulin were measured. Baseline and week-four results were compared with a Wilcoxon signed ranks test.

RESULTS

Twenty-five women and 18 men participated. Basal median LDL-C level of men was 3.11 and basal median LDL-C level of women was 3.00 mmol/l. After four weeks of a low-carbohydrate diet, the median energy intake decreased from 1901 to 1307 kcal/day, daily energy from carbohydrate from 55% to 33%, body weight from 87.7 to 83.0 kg and HDL-C increased from 0.83 to 0.96 mmol/l in men (p < 0.002, for all). After four weeks of a low-carbohydrate diet, the median energy intake tended to decrease (from 1463 to 1243 kcal, p = 0.052), daily energy from carbohydrate decreased from 53% to 30% (p < 0.001) and body weight decreased from 73.2 to 70.8 kg (p < 0.001) in women, but HDL-C did not significantly change (from 1.03 to 1.01 mmol/l, p = 0.165). There were significant decreases in body mass index, waist circumference, body fat ratio, systolic blood pressure, total cholesterol, triglyceride and insulin levels in all subjects.

CONCLUSIONS

HDL-C levels increased significantly with energy restriction, carbohydrate restriction and weight loss in men. HDL-C levels didn't change in women in whom there was no significant energy restriction but a significant carbohydrate restriction and a relatively small but significant weight loss. Our results suggest that both energy and carbohydrate restriction should be considered in overweight and obese subjects with low HDL-C levels, especially when LDL-C levels are not elevated.

Dietary protein and risk of ischemic heart disease in middle-aged men

BACKGROUND

Prospective studies in US women have suggested an inverse relation between dietary protein and risk of ischemic heart disease (IHD). However, no large-scale prospective studies have been conducted in US men.

OBJECTIVE

The objective was to examine the association between dietary protein and risk of IHD in a prospective study of US men.

DESIGN

Intakes of protein and other nutrients were assessed by using a validated food-frequency questionnaire at 4 time points during follow-up of 43,960 men participating in the Health Professionals Follow-Up Study. Cox proportional hazards models were used to calculate multivariable-adjusted relative risks (RRs) and 95% CIs.

RESULTS

During 18 y of follow-up, we documented 2959 incident cases of IHD. The RR of IHD was 1.08 (95% CI: 0.95, 1.23; P for trend = 0.30) comparing the top with the bottom quintile of percentage of energy from total protein. RRs for animal and vegetable protein were 1.11 (95% CI: 0.97, 1.28; P for trend = 0.18) and 0.93 (95% CI: 0.78, 1.12; P for trend = 0.49), respectively. When the population was restricted to "healthy" men (those free of hypertension, hypercholesterolemia, and diabetes at baseline), the RR of IHD was 1.21 (95% CI: 1.01, 1.44; P for trend = 0.02) for total protein, 1.25 (95% CI: 1.04, 1.51; P for trend = 0.02) for animal protein, and 0.93 (95% CI: 0.72, 1.19; P for trend = 0.65) for vegetable protein.

CONCLUSIONS

We observed no association between dietary protein and risk of total IHD in this group of men aged 40-75 y. However, higher intake of animal protein may be associated with an increased risk of IHD in "healthy" men.

Effect of a 21 day Daniel Fast on metabolic and cardiovascular disease risk factors in men and women

Background

Dietary modification via caloric restriction is associated with multiple effects related to improved metabolic and cardiovascular health. However, a mandated reduction in kilocalories is not well-tolerated by many individuals, limiting the long-term application of such a plan. The Daniel Fast is a widely utilized fast based on the Biblical book of Daniel. It involves a 21 day ad libitum food intake period, devoid of animal products and preservatives, and inclusive of fruits, vegetables, whole grains, legumes, nuts, and seeds. The purpose of the present study was to determine the efficacy of the Daniel Fast to improve markers of metabolic and cardiovascular disease risk.

Methods

43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day period of modified food intake in accordance with detailed guidelines provided by investigators. All subjects purchased and prepared their own food. Following initial screening, subjects were given one week to prepare for the fast, after which time they reported to the lab for their pre-intervention assessment (day 1). After the 21 day fast, subjects reported to the lab for their post-intervention assessment (day 22). For both visits, subjects reported in a 12 hr fasted state, performing no strenuous physical activity during the preceding 24-48 hrs. At each visit, mental and physical health (SF-12 form), resting heart rate and blood pressure, and anthropometric variables were measured. Blood was collected for determination of complete blood count, metabolic panel, lipid panel, insulin, HOMA-IR, and C-reactive protein (CRP). Subjects' self-reported compliance, mood, and satiety in relation to the fast were also recorded. Diet records were maintained by all subjects during the 7 day period immediately prior to the fast (usual intake) and during the final 7 days of the fast.

Results

Subjects' compliance to the fast was 98.7 ± 0.2% (mean ± SEM). Using a 10 point scale, subjects' mood and satiety were both 7.9 ± 0.2. The following variables were significantly (p < 0.05) lower following the fast as compared to before the fast: white blood cell count (5.68 ± 0.24 vs. 4.99 ± 0.19 10³·μL^-1), blood urea nitrogen (13.07 ± 0.58 vs. 10.14 ± 0.59 mg·dL^-1), blood urea nitrogen/creatinine (14.74 ± 0.59 vs. 11.67 ± 0.68), protein (6.95 ± 0.07 vs. 6.77 ± 0.06 g·dL^-1), total cholesterol (171.07 ± 4.57 vs. 138.69 ± 4.39 mg·dL^-1), LDL-C (98.38 ± 3.89 vs. 76.07 ± 3.53 mg·dL^-1), HDL-C (55.65 ± 2.50 vs. 47.58 ± 2.19 mg·dL^-1), SBP (114.65 ± 2.34 vs. 105.93 ± 2.12 mmHg), and DBP (72.23 ± 1.59 vs. 67.00 ± 1.43 mmHg). Insulin (4.42 ± 0.52 vs. 3.37 ± 0.35 μU·mL^-1; p = 0.10), HOMA-IR (0.97 ± 0.13 vs.0.72 ± 0.08; p = 0.10), and CRP (3.15 ± 0.91 vs. 1.60 ± 0.42 mg·L^-1; p = 0.13), were lowered to a clinically meaningful, albeit statistically insignificant extent. No significant difference was noted for any anthropometric variable (p > 0.05). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total kilocalorie intake (2185 ± 94 vs. 1722 ± 85).

Conclusion

A 21 day period of modified dietary intake in accordance with the Daniel Fast is 1) well-tolerated by men and women and 2) improves several risk factors for metabolic and cardiovascular disease. Larger scale, randomized studies, inclusive of a longer time period and possibly a slight modification in food choice in an attempt to maintain HDL cholesterol, are needed to extend these findings.

Rice protein isolate improves lipid and glucose homeostasis in rats fed high fat/high cholesterol diets

In order to understand the molecular mechanisms underlying effects of feeding rice protein on lipid and glucose homeostasis, weanling rats were fed AIN-93G diets made with casein or rice protein isolate (RPI) for 14 d. Peroxisome proliferator-activated receptor (PPAR)alpha genes and proteins involved in fatty acid degradation were upregulated by feeding RPI (P < 0.05), accompanied by increased promoter binding and nuclear expression of PPARalpha and its heterodimerization partner retinoid X receptor (P < 0.05). Effects of RPI feeding on hepatic PPARgamma signaling were significant but less robust. Feeding RPI also increased hepatic genes involved in cholesterol metabolism and transport. However, feeding RPI had no effect on binding of liver X-receptor (LXR)alpha to the cytochrome P450 (CYP)7A1 promoter. The effect of RPI feeding on PPARalpha signaling appeared to be direct and was reversed when RPI diets were switched to casein. In another experiment, male Sprague-Dawley rats were fed casein diets from postnatal day (PND) 24 to PND64 or were fed high fat 'Western' diets containing 0.5% cholesterol made with either casein or RPI. Increased liver triglyceride content, hypercholesterolemia and insulin resistance in the 'Western' diet-fed rats were partially prevented by feeding RPI (P < 0.05). mRNA and protein expression of hepatic enzymes involved in fatty acid synthesis were suppressed by feeding 'Western diets' containing RPI (P < 0.05), despite a lack of effects on nuclear concentrations of sterol regulatory element binding protein-1c. These data suggest that attenuation of metabolic syndrome observed in RPI-fed rats after consumption of diets high in fat and cholesterol occur as a result of improved lipid and glucose homeostasis partly as a result of activation of PPARs.

Nuts, metabolic syndrome and diabetes

The ability of nuts to improve the blood lipid profile and reduce the risk of CHD is now well established. The interest that health effects of nuts have gained recently has brought the possible benefits of consuming nuts, such as improvement in the conditions of the metabolic syndrome, and their potential to prevent and control diabetes into focus. Results from cohort studies have associated nut consumption with a reduced risk of developing diabetes and CVD. However, few randomised controlled trials have assessed the effect of nuts on diabetes control, and those that have been undertaken have shown improvements in blood lipids but not in the glycaemic control. Diabetes agencies are increasingly recognising the importance of controlling postprandial glycaemia fluctuations. Acute feeding studies indicate that nuts have minimal effects on rising postprandial blood glucose levels when eaten alone, and diminish the postprandial glycaemic response when consumed with high-glycaemic index carbohydrate foods in both normoglycaemic and type 2 diabetic individuals. Nuts have a healthy nutritional profile, high in MUFA and PUFA, are a good source of vegetable protein and are rich in fibre, vitamins and minerals. Incorporation of nuts in the diet may therefore improve the overall nutritional quality of the diet. While more research is required to establish the ability of nuts to improve glycaemic control in the long run, early data indicate that the inclusion of nuts in the diets of individuals with diabetes and the metabolic syndrome is warranted, in view of their potential to reduce CHD risk.

Purines and the Anti-Epileptic Actions of Ketogenic Diets

Ketogenic diets are high in fat and low in carbohydrates and represent a well-established and effective treatment alternative to anti-epileptic drugs. Ketogenic diets are used for the management of a variety of difficult-to-treat or intractable seizure disorders, especially pediatric refractory epilepsy. However, it has been shown that this dietary therapy can reduce seizures in people of all ages, and ketogenic diets are being applied to other prevalent medical conditions such as diabetes. Although used effectively to treat epilepsy for nearly 90 years, the mechanism(s) by which ketogenic diets work to reduce seizures remain ill-understood. One mechanism receiving increased attention is based on findings that ketogenic diets increase the brain energy molecule ATP, and may also increase the levels and actions of the related endogenous inhibitory neuromodulator adenosine. ATP and adenosine have both been identified as important modulators of seizures; seizures increase the actions of these purines, these purines regulate epileptic activity in brain, adenosine receptor antagonists are pro-convulsant, and adenosinergic mechanisms have been implicated previously in the actions of approved anti-epileptic therapeutics. Here we will review recent literature and describe findings that shed light on mechanistic relationships between ketogenic diets and the purines ATP and adenosine. These emerging mechanisms hold great promise for the effective therapeutic management of epileptic seizures and other neurological conditions.

Session 4: CVD, diabetes and cancer A dietary portfolio for management and prevention of heart disease

CHD is the leading cause of worldwide mortality. The prevalence of heart disease has been linked to the adoption of a sedentary lifestyle and the increased dietary dependence on saturated fats from animal sources and the intake of refined foods. Elevated blood cholesterol level is one of the major risk factors for CHD. While cholesterol-lowering drug therapy (statins) has been effective in reducing the risk of heart disease, there are those individuals who are unwilling or because of muscle pains or raised levels of liver or muscle enzymes are unable to take cholesterol-lowering medication. Fortunately, there is evidence linking a number of dietary components to CHD risk reduction. The strength of this evidence has prompted various regulatory bodies to advocate diet as the first line of defence for primary prevention of heart disease. It was therefore decided to combine four dietary components that have been shown to lower blood cholesterol concentrations (nuts, plant sterols, viscous fibre and vegetable protein) in a dietary portfolio in order to determine whether the combined effect is additive. In a metabolically-controlled setting this dietary portfolio has proved to be as effective as a starting dose of a first-generation statin cholesterol-lowering medication in reducing the risk of CHD. The dietary portfolio has also been shown to be effective in sustaining a clinically-significant effect in the long term under a ‘real-world’ scenario. However, success of the diet depends on compliance and despite the accessibility of the foods adherence has been found to vary greatly. Overall, the evidence supports the beneficial role of the dietary portfolio in reducing blood cholesterol levels and CHD risk.