The effect of fiber-rich carbohydrates on features of Syndrome X

Effect of Psyllium husk fiber and lifestyle modification on human body insulin resistance

Insulin resistance is a metabolic disorder that is increasing worldwide and is associated with some of the most common diseases affecting modern societies including diabetes, hypertension, obesity, and coronary heart disease. Changes in diet and physical activity have a profound effect on lowering the risk and cost of managing insulin resistance compared to the pharmacological approach. An interventional study of 16 weeks explored the effect of Psyllium husk fiber in combination with lifestyle modification on insulin resistance among the centrally obese school teachers of district Malakand Khyber Pakhtunkhwa. One Hundred twenty school teachers with central obesity, aged 40-60 years, with no chronic disease history were divided into four subgroups (n = 30) with equal gender bifurcation; a control group, lifestyle modification (LSM) group, psyllium husk fiber (PSH) group, and the combined intervention of LSM & PSH group. Fasting serum was collected to analyze fasting blood glucose, and insulin resistance by using the HOMA-IR method at baseline and post-intervention. A significant effect of the intervention was observed on fasting blood glucose. The combined group of LSM&PSH showed the highest mean change of -7.5 ± 2.6 mg/dl (-9%), followed by the PSH group with a mean change of -6.3 ± 2.1 mg/dl, (-7%). Likewise a significant effect (P < 0.05) on HOMA-IR was observed in the combined group of LSM&PSH with a mean of 1.02 ± 0.14 molar units (-58%), followed by the PSH group with a mean of 1.55 ± 0.14 molar units (-33%). The current study was carried out to assess the effect of regular consumption of Psyllium husk fiber in combination with lifestyle modification on insulin resistance and fasting blood glucose.

Working for Long Hours Is Associated With Dietary Fiber Insufficiency

It has been suggested that long working hours are associated with various diseases through dietary patterns. However, few studies have reported the association between working hours and dietary habits. Thus, the objective of this cross-sectional study was to explore the difference in dietary fiber intake by working hours. Data of a total of 10,760 workers in South Korea who participated in the Korea National Health and Nutrition Survey (KNHANES), a nation-wide survey, were analyzed to determine different distributions of dietary fiber insufficiency using multiple logistic regression models. Fiber insufficiency proportion was different from working hour groups. 70.1% of the total population eat fiber insufficiently. Working &lt;40 h group showed 66.8% of fiber insufficiency. But working more than 52 h group marked 73.2% of fiber insufficiency. Logistic regression analysis of 10,760 nation-wide study participants revealed that working for 41–52 h a week (OR: 1.32, 95% CI: 1.18–1.47) and working for over 52 h a week (OR: 1.42, 95% CI: 1.25–1.62) were significantly associated with insufficient fiber intake compared to workers with standard working hours (30–40 h a week). These associations were still robust in an adjusted model, with working for 41–52 h a week (OR: 1.13, 95% CI: 1.01–1.27) and working for over 52 h (OR: 1.26, 95% CI: 1.09–1.45) showing high associations with dietary fiber insufficiency. Those with long working hours tend to have insufficient intake of dietary fiber. To promote desirable dietary habits, intervention programs on working conditions should be considered.

Fibre Intake Is Associated with Cardiovascular Health in European Children

BACKGROUND

We aimed at analysing the association between dietary fibre intake during childhood and cardiovascular health markers.

METHODS

We used observational longitudinal analysis and recorded diet using 3-day diaries at the ages of 3, 4, 5, 6, and 8 years in children from the EU Childhood Obesity Project Trial. At the age of 8, waist circumference, systolic and diastolic blood pressure (SBP and DBP) and biochemical analyses (lipoproteins, triglycerides and homeostasis model for insulin resistance (HOMA-IR)) were evaluated. Those parameters were combined into a cardiometabolic risk score through the sum of their internal z-scores.

RESULTS

Four-hundred children (51.8% girls) attended to the 8-year visit with a 3-day diary. Adjusted linear regression models showed that children who repeatedly stayed in the lowest tertile of fibre intake during childhood had higher HOMA-IR (p = 0.004), higher cardiometabolic risk score (p = 0.02) and a nonsignificant trend toward a higher SBP at 8 years. The higher the dietary intake of soluble fibre (from fruits and vegetables) at 8 years, the lower the HOMA-IR and the cardiometabolic risk score (p = 0.002; p = 0.004). SBP was directly associated with fibre from potatoes and inversely with fibre from nuts and pulses.

CONCLUSION

A diet rich in dietary fibre from fruits, vegetables, pulses and nuts from early childhood was associated to a healthier cardiovascular profile, regardless of children's weight.

Dietary Factors in Reducing Risk of Cardiovascular Diseases

Diet influences many modifiable risk factors for cardiovascular diseases (CVDs). Considering this, moderation of total dietary fat, particularly trans and saturated fats, as well as cholesterol is recommended. Dietary fats should come mainly from plants and fatty fish, providing monounsaturated and polyunsaturated (including omega-3) fatty acids. Carbohydrate sources to emphasize include whole grains, legumes, vegetables, fruits, and other fiber-rich sources, rather than sugars. Although vitamins such as E, C, and some B vitamins are associated with reduced CVD risk, data do not support the use of supplements, but foods rich in these nutrients are advocated. Dietary minerals such as potassium, magnesium, and calcium may be beneficial to heart health, while reduction of dietary sodium decreases risk of hypertension. A large variety of phytonutrients are also associated with reduced CVD risk. Other dietary factors receiving research attention regarding CVD risk. Other dietary factors receiving research attention regarding CVD risk include caffeine, alcobol, and meal frequency, although more work is needed in these areas. In contrast, data are quite robust to support the importance of healthy body weight management in cardiovascular health. In general, diets based on a variety of less processed foods, mainly of plant origin, in the context of an active lifestyle, are conducive to heart health.

Dietary factors associated with metabolic syndrome and its components in overweight and obese Brazilian schoolchildren: a cross-sectional study

BACKGROUND

The metabolic syndrome (MS) has been assessed since childhood mainly because of the nutritional and epidemiological transition that has occurred worldwide. Our objectives were to explore the MS and its components according to anthropometric and demographic factors and to assess the relationship among MS components and dietary characteristics in overweight and obese schoolchildren.

METHODS

This was a cross-sectional study which included 147 schoolchildren (aged 6-10 years) from three elementary schools, with body mass index (BMI) higher than the 85th percentile. Sexual maturation stages, anthropometric measures (weight, height, skinfold thickness and waist circumference), biochemical data (glucose, HDL-C and triacylglycerol), blood pressure and dietary intake were assessed. The metabolic syndrome was diagnosed if three or more of the following components were presented: waist circumference ≥90th age and sex-specific cut-off, blood pressure ≥90th age, sex and height-specific cut-off, glucose ≥100 mg/dL, HDL-C ≥ 40 mg/dL and triacylglycerols ≥ 110 mg/dL. The dietary intake was assessed by three non-consecutive 24-h recalls. The T test, Kruskal-Wallis and multiple linear regression analysis were applied to assess MS components and dietary intake.

RESULTS

The MS percentage was 10.2 % and it was higher in obese children and ones with high body fat percentage. The waist circumference was the main altered component of MS and 62 % of overweight schoolchildren showed at least one altered component of MS. The components of metabolic syndrome associated with dietary intake were triacylglycerol (positive association with saturated and monounsaturated fat, whole-milk products and processed foods and negative associated with legumes and polyunsaturated fat), glycemia (positive association with processed foods and negative with cereals), HDL-C (positive association with vegetables and greens) and waist circumference was negative associated with protein.

CONCLUSIONS

The frequency of MS was higher in obese than overweight schoolchildren and the frequency of at least one MS component was high in more than half of our subjects. The waist circumference was the most frequent among all other components. The triacylglycerol and glycemia were the most frequent MS components associated with dietary intake. Unprocessed food was considered a protective dietary factor for MS metabolic components and processed food with high percentage of sugar and saturated fat was a risk factor for MS metabolic components.

Independent and Combined Effects of Lactitol, Polydextrose, and Bacteroides thetaiotaomicron on Postprandial Metabolism and Body Weight in Rats Fed a High-Fat Diet

Obesity is related to the consumption of energy-dense foods in addition to changes in the microbiome where a higher abundance of gut Bacteroidetes can be found in lean subjects or after weight loss. Lactitol, a sweet-tasting sugar alcohol, is a common sugar-replacement in foods. Polydextrose (PDX), a highly branched glucose polymer, is known to reduce energy intake. Here, we test if the combined effects of lactitol or PDX in combination with Bacteroides species will have a beneficial metabolic response in rats fed a high-fat (HF) diet. A total of 175 male Wistar rats were fed either a LF or HF diet. Bacteroides thetaiotaomicron (10¹⁰ bacteria/animal/day) was orally administered with or without lactitol (1.6−2 g/animal/day) or PDX (2 g/animal/day) for 8 days. Postprandial blood samples, cecal digesta, and feces were collected on the last day. Measurements included: body weight, feed consumption, cecal short-chain fatty acids, fecal dry matter and heat value, blood glucose, insulin, triglyceride, and satiety hormone concentrations. Lactitol and PDX decreased the mean body weight when administered with B. thetaiotaomicron or when lactitol was administered alone. Levels of postprandial plasma triglycerides declined with lactitol and PDX when administered with B. thetaiotaomicron. For intestinal hormone release, lactitol – alone or with B. thetaiotaomicron – increased the release of gastrointestinal peptide tyrosine tyrosine (PYY) as well as the area under the curve (AUC) measured for PYY (0–8 h). In addition, levels of insulin AUC (0–8 h) decreased in the lactitol and PDX-supplemented groups. Lactitol and PDX may both provide additional means to regulate postprandial metabolism and weight management, whereas the addition of B. thetaiotaomicron in the tested doses had only minor effects on the measured parameters.

Cocoa polyphenols and fiber modify colonic gene expression in rats

Purpose

Cocoa intake has been associated with health benefits, improving cardiovascular function and metabolism, as well as modulating intestinal immune function. The aim of this study was to take an in-depth look into the mechanisms affected by the cocoa intake by evaluating the colonic gene expression after nutritional intervention, and to ascertain the role of the fiber of cocoa in these effects.

Methods

To achieve this, Wistar rats were fed for 3 weeks with either a reference diet, a diet containing 10 % cocoa (C10), a diet based on cocoa fiber (CF) or a diet containing inulin (I). At the end of the study, colon was excised to obtain the RNA to evaluate the differential gene expression by microarray. Results were validated by RT-PCR.

Results

The C10 group was the group with most changes in colonic gene expression, most of them down-regulated but a few in common with the CF diet. The C10 diet significantly up-regulated the expression of Scgb1a1 and Scnn1 g and down-regulated Tac4, Mcpt2, Fcer1a and Fabp1 by twofold, most of them related to lipid metabolism and immune function. The CF and I diets down-regulated the expression of Serpina10 and Apoa4 by twofold. Similar patterns of expression were found by PCR.

Conclusion

Most of the effects attributed to cocoa consumption on genes related to the immune system (B cell and mast cell functionality) and lipid metabolism in the colon tissue were due not only to its fiber content, but also to the possible contribution of polyphenols and other compounds.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-016-1230-0) contains supplementary material, which is available to authorized users.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

NUTRIOSE dietary fiber supplementation improves insulin resistance and determinants of metabolic syndrome in overweight men: a double-blind, randomized, placebo-controlled study

The influence of dietary fiber on determinants of metabolic syndrome is controversial. The objective of this study was to determine the effects of NUTRIOSE supplementation on insulin resistance and the determinants of metabolic syndrome in overweight men. In this double-blind, randomized, placebo-controlled study, we supplemented the diets of overweight Chinese men with 250 mL of fruit juice that contained NUTRIOSE (Test group: n = 60, age = 30.4 ± 4.3 years, body mass index (BMI) = 24.5 ± 0.2 kg·m–2) or a maltodextrin placebo (Control group: n = 60, age = 31.6 ± 4.1 years, BMI = 24.5 ± 0.3 kg·m–2) at a dosage of 17 g twice daily for 12 weeks. Daily caloric intake, body composition, blood chemistry, and blood pressure were evaluated every 4 weeks during the trial. Test subjects consumed fewer calories per day and had greater reductions in body weight, BMI, body fat percentage, and waist circumference than Control subjects. All markers of glucose metabolism improved in the Test group, with increases in adiponectin and reductions in glucose, insulin, homeostasis model assessment-estimated insulin resistance, glycosylated hemoglobin, and glycated albumin (all p < 0.01). Similarly, all lipid measures improved with increases in high-density lipoprotein cholesterol and reductions in total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglycerides (all p < 0.01). No changes were observed in systolic blood pressure between groups. Most components of glucose metabolism and the lipid profile were significantly better in the Test than in the Control subjects. No adverse events or gastrointestinal complaints were reported in either group. Supplementation with NUTRIOSE for 12 weeks is well tolerated, lowers insulin resistance, and improves determinants of metabolic syndrome in overweight men.

Relationship between number of metabolic syndrome components and dietary factors in middle-aged and elderly Japanese subjects

Metabolic syndrome (MetS) represents a cluster of risk factors for atherosclerosis and is considered a risk factor for cardiovascular disease. The role of diet in the etiology of MetS is poorly understood, especially among Asian subjects. This cross-sectional study assessed the relationship between diet and the number of MetS components among Japanese men (n=609) and women (n=631). Mean (s.d.) age and body mass index were 57.1 (12.1) years and 22.8 (2.8) kg m(-2) for men and 55.5 (12.0) years and 22.0 (3.0) kg m(-2) for women, respectively. Diet was assessed by a 3-day dietary record that included photographs: 16 nutrients, 11 food groups, and energy % of protein and dietary fat were selected as a dietary index. The definition of MetS was based on modified National Cholesterol Education Program, Adult Treatment Panel III criteria, and the number of clustering MetS components was calculated by adding the presence of each five MetS components. A total of 61 men (10.0%) and 46 women (7.3%) were determined to have MetS. After adjusting for age, energy intake, alcohol intake, smoking status and physical activity, a lower intake of vitamin B6 and dietary fiber in men, and lower intake of calcium, milk and dairy products and higher intake of cereal in women were related to the number of MetS components. These results suggest that some dietary factors were related to the number of MetS components among community-dwelling Japanese men and women.

Changes in arterial blood pressure of a soluble cocoa fiber product in spontaneously hypertensive rats

The effect produced by long-term intake of a soluble cocoa fiber product (SCFP) on the development of hypertension of spontaneously hypertensive rats (SHR) was evaluated. Twenty male 3-week-old SHR were divided into two groups of 10 animals that drank either tap water (control) or a solution of SCFP (0.75 g/day SCFP) until the 20th week of life. Five 20-week-old rats of each group were sacrificed. Tap water as drinking fluid was given to all the animals from the 20th to 24th week of life. The 24-week-old rats were also sacrificed. Body weight, liquid and dry food intake, and arterial blood pressure (tail cuff) were recorded weekly. Malondialdehyde (MDA), glucose and angiotensin converting enzyme (ACE) activity in the plasma from the sacrificed rats were also obtained, and we evaluated the relaxation caused by acetylcholine in the aorta from these animals. SCFP attenuated the development of hypertension in SHR; however, the withdrawal of SCFP caused an increase in blood pressure in the rats. Body weight gain was slower in the group treated with SCFP. SCFP increased liquid intake but decreased dry food intake in the rats. SCFP decreased plasma MDA concentrations and slightly decreased plasma ACE activity, but no differences were observed in plasma glucose and in the aorta responses to acetylcholine in both groups of 20-week-old SHR. We have demonstrated the antihypertensive and antioxidant properties of SCFP. The control of body weight and the control of increased angiotensin II may be involved in the antihypertensive effect of this product.

Design and methods for testing a simple dietary message to improve weight loss and dietary quality

BACKGROUND

The current food pyramid guidelines have been criticized because of their complexity and the knowledge required for users to understand the recommendations. Simplification of a dietary message to focus on a single key aspect of dietary quality, e.g., fiber intake, may make the message much easier to comprehend and adhere, such that respondents can achieve greater weight loss, better dietary quality and overall metabolic health.

METHODS AND DESIGN

This is a randomized controlled clinical trial with two equal sized arms. In total, 240 obese adults who meet diagnostic criteria for the metabolic syndrome will be randomized to one of the two conditions: 1) a high fiber diet and 2) the American Heart Association (AHA) diet. In the high fiber diet condition, patients will be given instruction only on achieving daily dietary fiber intake of 30 g or more. In the AHA diet condition, patients will be instructed to make the several dietary changes recommended by the AHA 2006 guidelines. The trial examines participant weight loss and dietary quality as well as changes in components of the metabolic syndrome, inflammatory biomarkers, low-density lipoprotein cholesterol levels, insulin levels, and glycosolated hemoglobin. Potential mediators, i.e., diet adherence and perceived ease of the diet, and the intervention effect on weight change will also be examined.

DISCUSSIONS

The purpose of this paper is to outline the study design and methods for testing the simple message of increasing dietary fiber. If the simple dietary approach is found efficacious for weight loss; and, improves dietary quality, metabolic health, and adherence, it might then be used to develop a simple public health message.

TRIAL REGISTRATION

NCT00911885.

No difference in the 24-hour interstitial fluid glucose profile with modulations to the glycemic index of the diet

OBJECTIVE

Reducing the glycemic index (GI) of the diet may decrease metabolic risk, primarily through reduction and stabilization of blood glucose. The objective of this research was to investigate whether incorporation of lower or higher GI foods into mixed meals had different effects on daylong glucose profiles, measured in interstitial fluid by a continuous glucose-monitoring system.

METHODS

The study was a randomized, balanced, two-way crossover intervention of 2 x 1-wk periods of lower and higher GI diets. Participants were 12 overweight healthy adult women (mean body mass index +/- standard deviation 27.5+/-2.3 kg/m(2)). Changes in GI were achieved through substitution of key staple carbohydrate-rich foods. After a 4-d run-in on each dietary regimen, participants wore the continuous glucose-monitoring system over 2 d of identical controlled feeding in the laboratory, separated by 1 d of ad libitum consumption at home.

RESULTS

On controlled days, diets differed in GI by 15 U and provided equal energy, macronutrients, and fiber. On ad libitum days, diet diaries revealed a difference in GI of 14+/-1 U (mean +/- standard error), with no detectable difference in energy, macronutrient, or fiber intake. No differences were observed in glucose profiles between higher and lower GI interventions in the controlled or ad libitum setting. There was significant agreement in area under the glucose curve on repeated controlled feeding days (intraclass correlation 0.75).

CONCLUSION

This study indicates that a difference in dietary GI of 14-15 U is insufficient to alter daylong glycemia as measured in interstitial fluid by the continuous glucose-monitoring system.

Dietary intakes of fiber and magnesium and incidence of metabolic syndrome in first year after renal transplantation

OBJECTIVE

Considering the high prevalence of metabolic syndrome (MetS) and the associated cardiovascular disease mortality after renal transplant, and considering that the lack of prospective studies regarding the role of fiber and magnesium in MetS prevention after transplant precludes definitive recommendations, we prospectively evaluated the potential role of fiber and magnesium intake in the incidence of MetS at 1 year after renal transplantation.

DESIGN

This was a prospective cohort study.

SETTING, PARTICIPANTS, AND MEASUREMENTS

We included 160 recipients of kidney transplant (100 men and 60 women) aged over 18 years who were free of MetS or diabetes at time of transplant, and followed these patients for 1 year.

METHODS

The usual dietary intakes were assessed with a Willett-format 168-item food-frequency questionnaire. We defined MetS according to modified Adult Treatment Panel III guidelines. We categorized participants by tertiles of dietary fiber and magnesium. To determine associations of fiber and magnesium intake with MetS incidence 1 year posttransplant, we used multivariable logistic regression.

RESULTS

After controlling for potential confounders, including baseline body mass index and energy intake, subjects within the highest tertile of fiber intake had a lower odds ratio for incident MetS (odds ratio, 0.41; 95% confidence interval, 0.08 to 0.99; P < .05 for trend) than those in the lowest tertile. There was no significant overall association between magnesium intake and MetS.

CONCLUSIONS

These findings support current dietary recommendations to increase intakes of fiber-rich foods as a primary preventive approach against MetS and cardiovascular disease, which are very prevalent after renal transplant.

Health benefits of dietary fiber

Dietary fiber intake provides many health benefits. However, average fiber intakes for US children and adults are less than half of the recommended levels. Individuals with high intakes of dietary fiber appear to be at significantly lower risk for developing coronary heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal diseases. Increasing fiber intake lowers blood pressure and serum cholesterol levels. Increased intake of soluble fiber improves glycemia and insulin sensitivity in non-diabetic and diabetic individuals. Fiber supplementation in obese individuals significantly enhances weight loss. Increased fiber intake benefits a number of gastrointestinal disorders including the following: gastroesophageal reflux disease, duodenal ulcer, diverticulitis, constipation, and hemorrhoids. Prebiotic fibers appear to enhance immune function. Dietary fiber intake provides similar benefits for children as for adults. The recommended dietary fiber intakes for children and adults are 14 g/1000 kcal. More effective communication and consumer education is required to enhance fiber consumption from foods or supplements.

Metabolic effects of low glycaemic index diets

The persistence of an epidemic of obesity and type 2 diabetes suggests that new nutritional strategies are needed if the epidemic is to be overcome. A promising nutritional approach suggested by this thematic review is metabolic effect of low glycaemic-index diet. The currently available scientific literature shows that low glycaemic-index diets acutely induce a number of favorable effects, such as a rapid weight loss, decrease of fasting glucose and insulin levels, reduction of circulating triglyceride levels and improvement of blood pressure. The long-term effect of the combination of these changes is at present not known. Based on associations between these metabolic parameters and risk of cardiovascular disease, further controlled studies on low-GI diet and metabolic disease are needed.

Effects of dietary fibers on disturbances clustered in the metabolic syndrome

Because of its growing prevalence in Western countries, the metabolic syndrome, a common metabolic disorder that clusters a constellation of abnormalities, including central obesity, hypertension, dyslipidemia and insulin resistance, is emerging as one of the most important public health problems in the world, taking into account that it is a major risk factor mainly for type 2 diabetes and cardiovascular diseases, and also for many types of cancer. Although the pathogenesis of this syndrome is complex and not fully understood, obesity and insulin resistance, accompanied by an altered profile of number of hormones and cytokines produced by the adipose tissue, seem to be the main causative agents. A prime therapeutic approach to the prevention and treatment of this syndrome involves lifestyle changes. Among dietary modifications, dietary fiber intake could play an interesting role in the management of metabolic syndrome through different mechanisms related to its dietary sources, specific chemical structure and physical properties, or fermentability in the gut. According to all of these variables, the different types of dietary fibers have been reported to take part in the control of body weight, glucose and lipid homeostasis, insulin sensitivity and in the regulation of many inflammation markers involved in the pathogenesis of metabolic syndrome, and which are also considered to be among its features.

Carbohydrate quantity and quality in relation to body mass index

The increased prevalence of overweight and obesity in the United States since approximately 1980 is temporally associated with an increase in carbohydrate intake, with no appreciable change in absolute intake of fat. Despite speculation that both carbohydrate quantity and quality have contributed significantly to excess weight gain, the relationship between carbohydrate intake and body mass index (BMI) is controversial. A review of relevant literature indicates that most epidemiologic studies show an inverse relationship between carbohydrate intake and BMI, even when controlling for potential confounders. These observational studies are supported by results from a number of dietary intervention studies wherein modest reductions in body weight were observed with an ad libitum, low-fat, high-carbohydrate diet without emphasis on energy restriction or weight loss. With few exceptions, high glycemic load is associated with lower BMI, even when adjusted for total energy intake. Data on the association between glycemic index and BMI are not as consistent, with more studies showing either no association or an inverse relationship, rather than a positive relationship. Whole-grain intake is generally inversely associated with BMI; refined grain intake is not. Because overall dietary quality tends to be higher for high-carbohydrate diets, a low-fat dietary strategy with emphasis on fiber-rich carbohydrates, particularly cereal fiber, may be beneficial for health and weight control.

Nutritional strategies in the prevention and treatment of metabolic syndrome

The metabolic syndrome (MetS) is a clustering of metabolic abnormalities that increase the risk of developing atherosclerotic cardiovascular disease and type 2 diabetes. The exact etiology remains unclear, but it is known to be a complex interaction between genetic, metabolic, and environmental factors. Among environmental factors, dietary habits are of central importance in the prevention and treatment of this condition. However, there is currently no firm consensus on the most appropriate dietary recommendations. General recommendations include decreasing obesity, increasing physical activity, and consuming an anti-atherogenic diet, and have traditionally focused on low total fat intake. A major problem with the focus on low fat is that high-carbohydrate diets can contribute to increasing triglyceride and decreasing high-density lipoprotein (HDL) concentrations. Low-carbohydrate diets have been popular in recent years. However, such diets are typically higher in saturated fat and lower in fruits, vegetables, and whole grains than national dietary recommendations. More recently the quality of carbohydrate has been studied in relation to MetS, including a focus on dietary fiber and glycemic index. Similarly, there has been a move from limiting total fat to a focus on the quality of the fat, with evidence of beneficial effects of replacing some carbohydrate with monounsaturated fat. Other nutrients examined for possible importance include calcium, vitamin D, and magnesium. Together, the evidence suggests that the components of diet currently recommended as "healthy" are likely also protective against MetS, including low saturated and trans fat (rather than low total fat) and balanced carbohydrate intake rich in dietary fiber, as well as high fruit and vegetable intake (rather than low total carbohydrate); and the inclusion of low-fat dairy foods. Accelerating research on gene-diet interactions is likely to contribute interesting information that may lead to further individualized dietary guidance in the future.

Glycaemic index and metabolic disease risk

There is growing evidence that the type of carbohydrate consumed is important in relation to metabolic disease risk, and there is currently particular interest in the role of low-glycaemic-index (GI) foods. Observational studies have associated low-GI diets with decreased risk of type 2 diabetes and CHD, and improvements in various metabolic risk factors have been seen in some intervention studies. However, findings have been mixed and inconsistent. There are a number of plausible mechanisms for the effects of these foods on disease risk, which arise from the differing metabolic responses to low- and high-GI foods, with low-GI foods resulting in reductions in hyperglycaemia, hyperinsulinaemia and late postprandial circulating NEFA levels. Low-GI foods may also increase satiety and delay the return of hunger compared with high-GI foods, which could translate into reduced energy intake at later time points. However, the impact of a low-GI diet on body weight is controversial, with many studies confounded by dietary manipulations that differ in aspects other than GI. There is currently much interest in GI from scientists, health professionals and the public, but more research is needed before clear conclusions can be drawn about relationships with metabolic disease risk.

Consumption of whole-grain cereals during weight loss: effects on dietary quality, dietary fiber, magnesium, vitamin B-6, and obesity

OBJECTIVE

While various weight-management approaches produce weight loss, they may differ in dietary quality. We monitored changes in nutrient intakes in overweight and obese subjects on three different weight-management programs.

DESIGN

Randomized clinical trial (pilot study) with two 12-week phases: phase 1, weekly counseling; phase 2, monitoring only.

SUBJECTS/SETTING

One hundred eighty nonsmoking, sedentary overweight and obese adults began this outpatient study; 134 (body mass index [calculated as kg/m(2)]=30.9+/-2.4; age=42.3+/-1.2 years) were used in analyses.

INTERVENTION

Twenty-four weeks of exercise only (control group), hypocaloric diet plus exercise, or hypocaloric diet with fiber-rich whole-grain cereals plus exercise.

MAIN OUTCOME MEASURES

At weeks 0, 12, and 24, diet quality was assessed by 3-day food records and body weight was measured.

STATISTICAL ANALYSES PERFORMED

Three-way analysis of variance with repeated measures.

RESULTS

The hypocaloric diet with fiber-rich whole-grain cereals plus exercise decreased energy intake more than exercise only (P=0.032). By week 12, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise decreased total fat more than exercise only, which was sustained in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise at 24 weeks (P<0.001). At weeks 12 and 24, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise reduced saturated fat intake more than exercise only. The hypocaloric diet with fiber-rich whole-grain cereals plus exercise increased total fiber, insoluble fiber (both P<0.001), magnesium (P=0.004), and vitamin B-6 (P=0.002) intakes more than the hypocaloric diet plus exercise and exercise only. Calcium and vitamin E intakes were inadequate in all groups. Weight loss was similar in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise.

CONCLUSIONS

Weight-reduction strategies may be associated with reduced intake of micronutrients, such as calcium and vitamin E. However, a hypocaloric diet with fiber-rich whole-grain cereal is effective for improving or maintaining other aspects of dietary quality during weight loss.

Oligofructose promotes satiety in healthy human: a pilot study

OBJECTIVE

The administration of a fermentable dietary fibre (oligofructose) in rats increases satietogenic gut peptides and lowered spontaneous energy intake. The aim of the study was to assess the relevance of those effects of oligofructose on satiety and energy intake in humans.

DESIGN

Single-blinded, crossover, placebo-controlled design, pilot study.

SUBJECTS

Volunteers included five men and five women aged 21-39 years, BMI ranging from 18.5 to 27.4 kg/m(2), were randomly assigned as described below.

INTERVENTIONS

Subjects were included in two 2-week experimental phases during which they received either fibre (oligofructose (OFS)) or placebo (dextrine maltose (DM)); a 2-week washout period was included between crossover phases. In total, 8 g OFS or 8 g DM were ingested twice daily (16 g/day in total). Energy intake, hunger, satiety, fullness and prospective food consumption were assessed with analogue scales at the end of each experimental phase.

RESULTS

During breakfast, OFS significantly increases the satiety (P=0.04) without any difference on other sensations as compared to DM treatment periods. After lunch, no significant differences are observed between treatment period. At dinner, OFS significantly increases satiety (P=0.04), reduces hunger (P=0.04) and prospective food consumption (P=0.05). The energy intake at breakfast and lunch are significantly lower (P=0.01, 0.03, respectively) after OFS treatment than after DM treatment. Total energy intake per day is 5% lower during OFS than in DM period.

CONCLUSION

Oligofructose treatment increases satiety following breakfast and dinner, reduces hunger and prospective food consumption following dinner. This pilot study presents a rationale to propose oligofructose supplements in the management of food intake in overweight and obese patients.

Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca2+/K+ bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca2+ (495 mg, 49.5% of RDI) and K+ (720 mg, 15% of RDI). Ca2+ ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K+, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions.

A place for dietary fibre in the management of the metabolic syndrome

PURPOSE OF REVIEW

To control the global increase of obesity and associated-metabolic syndrome, nutritional advice remains an important objective. This review discusses factors that may explain how dietary fibre would be helpful in the management of food intake, body weight and metabolic syndrome.

RECENT FINDINGS

Dietary fibre could play a role in the management of the metabolic syndrome through its ability to control body weight evolution through its effect on satiety; to modulate glucose homeostasis/insulin sensitivity and to positively affect factors implicated in cardiovascular diseases. The relevance and the relative importance of these effects in control of metabolic syndrome remain unknown. Recent experimental data suggest that the modification of gut peptides--involved in appetite and glucose homeostasis--could constitute a 'metabolic relay' allowing specific (fermentable) dietary fibre to act on appetite and other components of the metabolic syndrome.

SUMMARY

Dietary fibre intake may modulate parameters associated with the control of the metabolic syndrome, namely food intake (and body weight), glycemia and insulinemia, blood lipids and blood pressure. The efficacy of dietary fibre differs according to their dietary sources (fruits, legumes or cereals), but also to their specific chemical structure, responsible for their physical properties (i.e. gel forming capacity) or for their fermentation capacity in the lower part of the gut. The fermentability of dietary fibre seems important to generate specific effects on satiety and glycemia through the release of gut peptides such as glucagon-like peptide-1.

Insulin and cancer

Obesity has recently been linked to mortality from the majority of cancers. The insulin/insulin-like growth factor (IGF) system may partly explain this effect. The metabolic syndrome, associated with hyperinsulinemia, may modulate this effect. Recent evidence supports the role of insulin and IGF-1 as important growth factors, acting through the tyrosine kinase growth factor cascade in enhancing tumor cell proliferation. In addition, the metabolic syndrome associated with a chronic inflammatory state and accompanying cytokine abnormalities may also contribute to tumor progression. Growing links between insulin and the etiology as well as prognosis in colon, prostate, pancreatic, and, particularly, breast cancer are reviewed. Of particular concern is the evidence that elevated IGF-1 may interfere with cancer therapy, adversely affecting prognosis. The role of insulin is of concern because of the increasing levels of obesity and the associated metabolic syndrome. Weight gain, through typical Western diet; limited levels of activity; and, more recently, stress-related changes in neuroendocrine function may lead to insulin resistance and hyperinsulinemia. The opportunity for a multidisciplinary approach involving nutrition, exercise, and stress reduction in an integrative setting may be crucial to limiting the insulin-resistant state and improving cancer outcomes.

High-fiber diet in HIV-positive men is associated with lower risk of developing fat deposition

BACKGROUND

Lipodystrophy has been described with increasing frequency in patients infected with HIV. This study focused on the identification of dietary components that may predispose HIV-positive patients to the development of fat deposition.

OBJECTIVE

We evaluated differences in past dietary intake between men with HIV who developed fat deposition and those who did not.

DESIGN

This nested case-control study consisted of 47 cases and 47 controls from the Nutrition for Healthy Living cohort. Food records from 6 to 24 mo before development of fat deposition in cases were analyzed and compared with food records from controls by using t tests for normally distributed nutrients and Wilcoxon rank-sum tests for nutrients with skewed distributions.

RESULTS

HIV-positive patients without fat deposition had greater overall energy intakes (kcal/kg; P = 0.03) and greater intakes of total protein (P = 0.01), total dietary fiber (P = 0.01), soluble dietary fiber (P = 0.01), insoluble dietary fiber (P = 0.03), and pectin (P = 0.02) than did HIV-positive patients with fat deposition. Those without fat deposition also tended to currently perform more resistance training (P = 0.05) and to not be current smokers (P = 0.05).

CONCLUSION

Our results indicate that an overall high-quality diet, rich in fiber and adequate in energy and protein, may be beneficial in preventing the development of fat deposition in persons infected with HIV. The results of this study further emphasize that a healthy lifestyle, including exercise and avoidance of unhealthy behaviors such as smoking, may also be similarly beneficial.