Dietary fiber and body weight

The acute effects of psyllium on postprandial lipaemia and thermogenesis in overweight and obese men

Overweight and obesity is one of the risk factors for developing CVD. At present, very little is known about the acute effects of dietary fibre on lipids, glucose and insulin, resting energy expenditure and diet-induced thermogenesis in overweight and obese individuals. This study examined the postprandial metabolic effects of dietary fibre in overweight and obese men. Ten overweight and obese men consumed a mixed meal accompanied by either a high-fibre or low-fibre supplement on two separate visits, in a random order, 1 week apart. Two isoenergetic breakfast meals with similar composition were consumed by ten overweight/obese men. The meals contained either a low (3 g) or high (15 g) amount of fibre, low-fibre meal (LFM) and high-fibre meal (HFM) respectively. Analysis was carried out using paired t test and ANOVA. Serum TAG incremental area under the curve during 6 h of the postprandial period was significantly lower after the consumption of HFM compared with LFM. At the first hour of the postprandial period, plasma apo B48 concentration after consumption of HFM was significantly lower compared with LFM. The resting energy expenditure and diet-induced thermogenesis after both meals was similar during 6 h of the postprandial period. Collectively, these findings suggest that a single acute dose of dietary fibre in the form of psyllium supplement can decrease arterial exposure to TAG and modify chylomicron responses in the postprandial period.

The evidence for dietary prevention and treatment of cardiovascular disease

During the past few decades numerous studies have reported the atherogenic potential of saturated fatty acids, trans-fatty acids, and cholesterol, and beneficial effects of fiber, phytostanols/phytosterols, n-3 fatty acids, a Mediterranean diet, and other plant-based approaches. The purpose of this article is to provide a comprehensive and systematic review of the evidence associated with key dietary factors and risk of cardiovascular disease-an umbrella term encompassing diseases that affect the heart and blood vessels, including coronary heart disease, coronary artery disease, dyslipidemia, and hypertension-in conjunction with the work of the American Dietetic Association Evidence Analysis Library review on diet and lipids, updated with new evidence from the past 2 years. The criteria used and results cited provide scientific rationale for food and nutrition professionals and other health professionals for counseling patients. Details of these searches are available within the American Dietetic Association Evidence Analysis Library online (http://adaevidencelibrary.com). Potential mechanisms and needs for future research are summarized for each relevant nutrient, food, or food component.

The effect of Korean pine nut oil (PinnoThin) on food intake, feeding behaviour and appetite: a double-blind placebo-controlled trial

Certain free fatty acids have been shown to have potent effects on food intake and self-reported changes in appetite; effects associated with increases in the release of endogenous cholecystokinin (CCK) and glucagon like peptide-1 (GLP-1). In the current study, the effects of a Korean pine nut oil product, PinnoThin, at doses 2 g, 4 g and 6 g triglyceride (TG) and 2 g free fatty acid (FFA), on food intake and appetite were examined in a cross-over double-blind placebo-controlled randomised counter-balanced design in 42 overweight female volunteers. 2 g FFA PinnoThin, given 30 minutes prior to an ad-libitum buffet test lunch, significantly reduced food intake (gram) by 9% (F(4,164) = 2.637, p = 0.036) compared to olive oil control. No significant effect of PinnoThin on macronutrient intake or ratings of appetite were observed. Given the recent data showing that the TG form of PinnoThin may also reduce appetite by increasing CCK release, the lack of any effect of the TG form found in this study could be attributed to the timing of the dosing regime. Collectively, these data suggest that PinnoThin may exert satiating effects consistent with its known action on CCK and GLP-1 release, and previously observed effects on self-reported appetite ratings.

Carbohydrate intake and obesity

The prevalence of obesity has increased rapidly worldwide and the importance of considering the role of diet in the prevention and treatment of obesity is widely acknowledged. This paper reviews data on the effects of dietary carbohydrates on body fatness. Does the composition of the diet as related to carbohydrates affect the likelihood of passive over-consumption and long-term weight change? In addition, methodological limitations of both observational and experimental studies of dietary composition and body weight are discussed. Carbohydrates are among the macronutrients that provide energy and can thus contribute to excess energy intake and subsequent weight gain. There is no clear evidence that altering the proportion of total carbohydrate in the diet is an important determinant of energy intake. However, there is evidence that sugar-sweetened beverages do not induce satiety to the same extent as solid forms of carbohydrate, and that increases in sugar-sweetened soft drink consumption are associated with weight gain. Findings from studies on the effect of the dietary glycemic index on body weight have not been consistent. Dietary fiber is associated with a lesser degree of weight gain in observational studies. Although it is difficult to establish with certainty that fiber rather than other dietary attributes are responsible, whole-grain cereals, vegetables, legumes and fruits seem to be the most appropriate sources of dietary carbohydrate.

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.

State of the Art Reviews: The Oatmeal-Cholesterol Connection: 10 Years Later

Ten years have passed since the Food and Drug Administration (FDA) completed their review of the literature pertaining to the consumption of whole-oat sources of soluble fiber and a reduction in blood cholesterol concentrations. Since that time, data have continued to accumulate regarding oat-soluble fiber consumption, cholesterol, and other physiologic vectors related to cardiovascular health. The objective of this review was to compare the findings of more contemporary analyses of the oat and cholesterol-reduction literature to determine if newer information is consistent with the original conclusion reached by the FDA. A number of formal assessments have been conducted subsequent to the FDA review, and virtually all have reached the same conclusion, namely, consumption of oats and oat-based products significantly reduces total cholesterol and low-density lipoprotein cholesterol concentrations without adverse effects on high-density lipoprotein cholesterol or triglyceride concentrations. In addition, a number of new insights about the potential benefits of oats have emerged over the past 10 years. These more recent data indicate that including oats and oat-based products as part of a lifestyle management program may confer health benefits that extend beyond total cholesterol and low-density lipoprotein cholesterol reduction.

Effect of a balanced mixture of dietary fibers on gastric emptying, intestinal transit and body weight

BACKGROUND/AIMS

Dietary fibers are frequently included in diets to decrease body weight, but their scarce palatability and the occurrence of meteorism prevent a long-term intake. The aim of this study was to test a mixture of dietary fibers expressly chosen to decrease their negative properties and strengthen their positive effects.

METHODS

In a series of 10 patients with a slight overweight, the effectiveness of a palatable dietary fibers mixture on gastric emptying and intestinal transit was tested with scintigraphic methods. Then, the effects on body weight and digestive sensations and characteristics of defecations, were evaluated for 4 weeks.

RESULTS

The intestinal transit was significantly shortened by the fiber intake, while the gastric emptying was delayed, but not significantly. The body mass index significantly and progressively decreased, whereas the sense of satiation significantly increased. No effect on abdominal bloating was referred, whereas a significant increase in number of defecations with stools of normal consistency was observed. The acceptability of the fiber mixture was good.

CONCLUSIONS

The present research demonstrated that it is possible to prepare a palatable mixture of dietary fibers that maintains the property of decreasing body weight, favors the sense of satiation and accelerates the intestinal transit, with normalization of the stool consistency without the occurrence of meteorism.

State of the Art Reviews: The Oatmeal-Cholesterol Connection: 10 Years Later

Ten years have passed since the Food and Drug Administration (FDA) completed their review of the literature pertaining to the consumption of whole-oat sources of soluble fiber and a reduction in blood cholesterol concentrations. Since that time, data have continued to accumulate regarding oat-soluble fiber consumption, cholesterol, and other physiologic vectors related to cardiovascular health. The objective of this review was to compare the findings of more contemporary analyses of the oat and cholesterol-reduction literature to determine if newer information is consistent with the original conclusion reached by the FDA. A number of formal assessments have been conducted subsequent to the FDA review, and virtually all have reached the same conclusion, namely, consumption of oats and oat-based products significantly reduces total cholesterol and low-density lipoprotein cholesterol concentrations without adverse effects on high-density lipoprotein cholesterol or triglyceride concentrations. In addition, a number of new insights about the potential benefits of oats have emerged over the past 10 years. These more recent data indicate that including oats and oat-based products as part of a lifestyle management program may confer health benefits that extend beyond total cholesterol and low-density lipoprotein cholesterol reduction.

Association between dietary fiber and endometrial cancer: a dose-response meta-analysis

BACKGROUND

Endometrial cancer is the most common female gynecologic cancer in the United States. Excessive and prolonged exposure of the endometrium to estrogens unopposed by progesterone and a high body mass are well-established risk factors for endometrial cancer. Although dietary fiber has been shown to beneficially reduce estrogen concentrations and prevent obesity, its role in endometrial cancer has received relatively little attention.

OBJECTIVE

The objective was to summarize and quantify the current evidence of a role of dietary fiber consumption in endometrial cancer risk and to identify research gaps in this field.

DESIGN

We conducted a systematic literature review of articles published through February 2007 to summarize the current evidence of a relation between dietary fiber consumption and endometrial cancer risk and to quantify the magnitude of the association by conducting a dose-response meta-analysis.

RESULTS

Ten articles representing 1 case-cohort study and 9 case-control studies that evaluated several aspects of fiber consumption and endometrial cancer risk were identified through searches in various databases. On the basis of 7 case-control studies, the random-effects summary risk estimate was 0.82 (95% CI: 0.75, 0.90) per 5 g/1000 kcal dietary fiber, with no evidence of heterogeneity (I(2): 0%, P for heterogeneity: 0.55). The random-effects summary estimate was 0.71 (95% CI: 0.59, 0.85) for the comparison of the highest with the lowest dietary fiber intake in 8 case-control studies, with little evidence of heterogeneity (I(2): 20.8%, P for heterogeneity: 0.26). In contrast, the only prospective study that evaluated this association did not find an association.

CONCLUSIONS

Although the current evidence, based on data from case-control studies, supports an inverse association between dietary fiber and endometrial cancer, additional population-based studies, particularly cohort studies, are needed before definitive conclusions can be drawn.

Effect of two doses of a mixture of soluble fibres on body weight and metabolic variables in overweight or obese patients: a randomised trial

The aim of the study was to compare the effect of the administration of a mixture of fibres on body weight-loss, satiety, lipid profile and glucose metabolism. We included 200 overweight or obese patients in a parallel, double-blind, placebo-controlled clinical trial, who were randomised to receive, in the context of an energy-restricted diet for a period of 16 weeks, a mixed fibre dose (3 g Plantago ovata husk and 1 g glucomannan) twice (b.i.d. group) or three times daily (t.i.d. group) or placebo. Weight change was the primary efficacy endpoint. Satiety, dietary compliance, lipid profile, glucose tolerance, insulin resistance and high-sensitivity C-reactive protein were secondary endpoints. Weight loss tended to be higher after both doses of fibre (-4.52 (SD 0.56) and -4.60 (SD 0.55) kg) than placebo (-0.79 (SD 0.58) kg); the differences in changes between groups were not statistically significant. Postprandial satiety increased in both fibre groups compared to the placebo. The differences between groups in LDL-cholesterol levels were significant (P = 0.03), with greater reductions in the two fibre-supplemented groups (-0.38 (SD 0.10) and -0.24 (SD 0.09) mmol/l in the b.i.d. and t.i.d. groups v. -0.06 (SD 0.09) mmol/l in placebo group). A similar pattern was observed for changes in total cholesterol:HDL-cholesterol and HDL-cholesterol:LDL-cholesterol ratios. Interventions were well tolerated and had no effects on HDL-cholesterol, glucose and insulin concentrations, glucose tolerance or high-sensitivity C-reactive protein. In conclusion, a 16-week dietary supplement of soluble fibre in overweight or obese patients was well tolerated, induced satiety and had beneficial effects on some CVD risk factors, the most important of which was a significant decrease in plasma LDL-cholesterol concentrations.

General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

BACKGROUND

Excess body fat accumulation may begin in youth and is linked with increased risk of cardiovascular disease. Examination of physical activity (PA) and diet behaviours predictive of adiposity may help target efforts to reduce chronic disease risk.

OBJECTIVE

We hypothesized that energy intake (EI) from fat, vigorous PA (VPA), and their interaction would predict body fat percentage (%BF) and visceral adipose tissue (VAT) in youth and that sedentary behaviours and intake of dairy, fruit, vegetable and whole grain foods would be related to adiposity.

DESIGN

A cross-sectional, observational study of reported PA and diet behaviours and objective adiposity measures.

SUBJECTS

Six-hundred sixty-one healthy black and white adolescents aged 14-18 years.

MEASUREMENTS

Diet by 24-h recalls using Nutrition Data Systems for Research (Minneapolis, MN, USA), VPA by previous day physical activity recalls (PAR), and %BF with dual-energy X-ray absorptiometry. VAT by magnetic resonance imaging for 434 subjects.

RESULTS

Reported EI and VPA were positively correlated with each other and were negative predictors of %BF. Time spent watching television or movies and %EI from protein were positive predictors of %BF. Adjusted for EI, none of the independent variables predictive of %BF retained their significance. %BF and VAT were highly correlated (r=0.73, P<0.0001). EI was the sole and negative predictor of VAT.

CONCLUSIONS

Higher energy 'throughput', not energy restriction, characterize leaner youths. Youths should be advised to engage in VPA so that they can eat sufficient calories to obtain the nutrients required for optimal health while remaining lean.

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.

Relationship of glycaemic index with cardiovascular risk factors: analysis of the National Diet and Nutrition Survey for people aged 65 and older

Objective

To identify associations between dietary glycaemic index (GI) and weight, body mass index and other risk factors for cardiovascular disease (CVD) – waist-to-hip ratio (WHR), lipoprotein fractions, triacylglycerols (TAG) and blood pressure (BP) – in an older British population.

Design

Cross-sectional dietary, anthropometric and biochemical data from the National Diet and Nutritional Survey for adults aged over 65 years were reanalysed using a hierarchical regression model. Associations between body weight, CVD risk factors, and dietary factors including GI and fibre intakes were explored among 1152 healthy older people living in the UK between 1994 and 1995.

Results

In the unadjusted model, GI was significantly and directly associated with TAG (β = 0.008 ± 0.003) and diastolic BP (β = 0.325 ± 0.164) in males. These relationships were attenuated and non-significant after adjustment for potential confounding factors. WHR (β = 0.003 ± 0.001) and TAG (β = 0.005 ± 0.002) were significantly predicted by GI in males and females combined. The association with WHR was attenuated by adjustment for sex, age, region and social class; the relationship with TAG was non-significant after adjustment for other potential dietary confounders.

Conclusion

After controlling for potential confounders, no clear links were detected between GI and body weight or other CVD risk factors. This study provides little evidence for advising the consumption of a low-GI diet in the elderly to prevent weight gain or improve other CVD risk factors.

Insoluble cereal fiber reduces appetite and short-term food intake and glycemic response to food consumed 75 min later by healthy men

BACKGROUND

Insoluble fiber consumption is associated with reduced risk of obesity and diabetes, but its mechanisms of action are unknown.

OBJECTIVE

The objective was to describe the effect of insoluble fiber on appetite, short-term food intake, and blood glucose (BG) before and after a meal 75 min later in healthy men.

DESIGN

In a crossover design, high-fiber (HF; 33 g insoluble fiber) cereal, low-fiber (LF) cereal, white bread (WB), and water control were administered to young men after an overnight fast. Caloric treatments had similar energy, macronutrient content, volume, and weight. In the first experiment, subjective appetite and BG were measured at 15-min intervals before and after an ad libitum meal at 75 min. In the second experiment, a preset pizza meal (850 kcal) was consumed at 75 min. Appetite and blood glucose were measured for 150 min at fasting and at 15-min intervals before and after the fixed meal.

RESULTS

In experiment 1, ad libitum food intake was lower after the HF cereal and WB than after the LF cereal and water (937 +/- 86, 970 +/- 65, 1109 +/- 90, 1224 +/- 89 kcal, respectively; P < 0.001). Appetite was lower (P < 0.05) after the HF cereal than after the WB but not different from the LF cereal. The BG area under the curve (AUC) did not differ among the HF cereal, WB, and LF cereal from 0 to 75 min, but the postmeal BG increased after the WB and LF cereal but not after the HF cereal. In experiment 2, the HF cereal, but not the LF cereal or WB, increased fullness before and prevented an increase in the BG AUC after the preset meal (P < 0.05).

CONCLUSION

A serving of 33 g insoluble fiber reduced appetite, lowered food intake, and reduced glycemic response to a meal consumed 75 min later.

Whole-grain consumption, dietary fibre intake and body mass index in the Netherlands cohort study

OBJECTIVES

To assess the association of whole-grain and (cereal) fibre intake with body mass index (BMI) and with the risk of being overweight (BMI> or =25) or obese (BMI> or =30 kg m(-2)).

SUBJECTS

A total of 2078 men and 2159 women, aged 55-69 years, were included in the analysis, after exclusion of subjects with diagnosed cancer or deceased within 1 year after baseline or with missing dietary information.

RESULTS

We found an inverse association between whole-grain consumption and BMI and risk of overweight and obesity in men as well as women. The association in men was stronger than in women; the risk of being obese as compared to normal weight was 10% (95% CI: 2-16%) and 4% (95% CI: 1-7%) lower for each additional gram of (dry) grain consumption in men and women, respectively. Fibre and cereal fibre intake were inversely associated with BMI in men only. Associations were similar after exclusion of likely under- and overreporters of energy. A retrospective analysis of baseline fibre intake and weight gain after the age of 20 years also showed a slight inverse association.

CONCLUSIONS

Whole-grain consumption may protect against becoming overweight or obese; however, the cross-sectional design of the study does not allow conclusions about the causality of the association.

Whole grains and adiposity: little association among British adults

OBJECTIVES

To examine associations of whole-grain intake with body weight and adiposity in two nationally representative samples of British adults.

SUBJECTS/METHODS

A total of 2064 adults aged 16-64 years in 1986-1987, 1599 adults aged 19-64 years in 2000-2001. Whole-grain intake (g day(-1) and 16-g amounts) was estimated from consumption of all foods with >or=10, >or=25 or >or=51% whole-grain content, using 7-day weighed dietary records. Body weight, body mass index (BMI) and, in 2000-2001, waist circumference (WC) were measured. BMI and WC were considered as continuous and categorical variables. For each survey, associations of whole-grain intake with body weight and anthropometric indices were examined in men and women separately, before and after adjustment for age, occupational social class, smoking habit, region, season and, in 2000-2001, misreporting.

RESULTS

In 1986-1987, whole-grain intake was inversely associated with percentage of men classified using BMI as obese (P=0.008, trend), independent of other factors. However, intake was not associated with body weight or prevalence of overweight. No corresponding associations were observed among women. In 2000-2001, whole-grain intake was not associated with body weight, BMI or WC.

CONCLUSIONS

Two national surveys of British adults, with detailed quantitative estimates of whole-grain intake, provide little evidence of an association of whole-grain intake with body weight or measures of adiposity.

Effect of chronic consumption of almonds on body weight in healthy humans

Small changes of diet may reduce CVD risk. One example is the inclusion of nuts. They are rich in fibre, unsaturated fatty acids and phytonutrients. However, their fat content and energy density raise concerns that chronic consumption will promote weight gain. Randomised intervention studies are required to evaluate whether this concern is well founded. This study's aim was to determine if the inclusion of a 1440 kJ serving of almonds in the daily diet results in positive energy balance, and body composition change. During a 23-week cross-over design study, participants were required to consume almonds for 10 weeks and were provided no advice on how to include them in their diet. For another 10 weeks (order counter-balanced), participants followed their customary diet and there was a 3-week washout between. The study group consisted of twenty women. Potential mechanisms of energy dissipation were measured. Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources. Moreover, inefficiency in the absorption of energy from almonds was documented (P < 0·05). No changes in resting metabolic rate, thermic effect of food or total energy expenditure were noted. A daily 1440 kJ serving of almonds, sufficient to provide beneficial effects on cardiovascular risk factors, may be included in the diet with limited risk of weight gain. Whether this can be generalised to other high-fat energy dense foods warrants evaluation.

The NHF-NRG In Balance-project: the application of Intervention Mapping in the development, implementation and evaluation of weight gain prevention at the worksite

Very few examples of theory-driven and systematically developed weight gain prevention interventions for adults have been described in the literature. The present paper systematically describes the development, implementation and evaluation framework of a weight gain prevention programme directed at young adults at the worksite, namely the NHF-NRG In Balance-project. It not only can be used as a guide to systematically develop weight gain prevention interventions, but also gives an overview of the current theoretical and empirical knowledge-base in the field of obesity prevention. The outline of the paper follows the Intervention Mapping protocol, which includes a systematic inventory of important health issues, their risk behaviours and determinants of these risk behaviours, and specification of the proximal objectives of the programme directed at both energy intake and energy expenditure. The objectives are translated into behaviour change methods and strategies, which are combined in a stepwise intervention programme, and used for a detailed evaluation plan (process and effect evaluation). The NHF-NRG In Balance-project combines mass media and individually tailored communications with worksite environmental changes to raise awareness, to motivate and to enable energy balance behaviour changes. A quasi-experimental pre-test-multiple post-test control group design was applied in 12 worksites (>500 employees).

Carob pulp preparation rich in insoluble dietary fibre and polyphenols increases plasma glucose and serum insulin responses in combination with a glucose load in humans

Dietary fibre consumption is associated with improved glucose homeostasis. In contrast, dietary polyphenols have been suggested to exert both beneficial and detrimental effects on glucose and insulin metabolism. Recently, we reported that a polyphenol-rich insoluble dietary fibre preparation from carob pulp (carob fibre) resulted in lower postprandial acylated ghrelin levels after a liquid meal challenge test compared with a control meal without supplementation. The effects may, however, differ when a different food matrix is used. Thus, we investigated the effects of carob fibre on glucose, insulin and ghrelin responses in healthy humans in combination with a glucose load. In a randomized single-blind cross-over study involving twenty healthy subjects (aged 22-62 years), plasma glucose, total and acylated ghrelin, and serum insulin were repeatedly assessed before and after the ingestion of 200 ml water with 50 g glucose and 0, 5, 10 or 20 g carob fibre over a period of 180 min. The intake of 5 and 10 g carob fibre increased the plasma glucose by 47 % and 64 % (P < 0.001), and serum insulin by 19.9 and 24.8 % (P < 0.001), compared with the control. Plasma acylated ghrelin concentrations did not change significantly after the consumption of carob-enriched glucose solution. Total ghrelin decreased only after 10 g carob fibre (P < 0.001) compared with control. In conclusion, we showed that polyphenol-rich carob fibre, administered within a water-glucose solution, increases postprandial glucose and insulin responses, suggesting a deterioration in glycaemic control.

Nutritional evaluation of protein, phosphorus, calcium and magnesium bioavailability from lupin (Lupinus albus var. multolupa)-based diets in growing rats: effect of α-galactoside oligosaccharide extraction and phytase supplementation

The nutritional composition of the legume Lupinus albus var. multolupa, raw or after α-galactoside extraction, and its effect on the bioavailability of protein, P, Ca, and Mg by growing rats wasevaluated using a balance technique. The protein and dietary fibre content of the lupin floursstudied was high, and 89–94% of the dietary fibre was present as insoluble dietary fibre. The α-galactoside extraction process did not disrupt the nutritional quality of protein, and the digestive and metabolic utilisation of this nutrient was high and comparable with that obtained from a casein–cystine control diet (pair-fed to the average daily food intake of the experimental groups fed the different lupin diets). Bioavailability of P, Ca, and Mg from the lupin diets tested was high, and supplementation of an exogenous microbial phytase (750 phytase units/kg) did not cause any further improvement. Mineral content in the bone tissue (femur and sternum) did not correlate to mineral balance, which, on the other hand, was related to the mineral content of other tissues such as blood, plasma, liver and kidney. Due to its ability to grow under adverse edaphic and climatic conditions and to its good nutritional quality, α-galactoside-free lupin flour supplemented with the required amounts of minerals and vitamins to meet nutrient requirements can be used as an excellent dietary source for the preparation of dietetic products.

Food preference questionnaire as a screening tool for assessing dietary risk of cardiovascular disease within health risk appraisals

OBJECTIVE

Nutrition components of health risk appraisals (HRAs) aim to rapidly and accurately assess dietary behaviors that increase disease risk. Because cognitive research suggests that recalling food likes/dislikes may be simpler and more accurate than recalling intake, we tested whether a preference measure was predictive of cardiovascular disease risk factors within an HRA.

METHODS

HRA participants (422 primarily non-Hispanic white men, mean age 46+/-10 years) from a manufacturing company completed surveys to assess fat and sweet food/beverage preference; frequency of consuming fat and sweet foods/beverages, alcoholic beverages, fiber-rich foods (whole grains, fruits, and vegetables); and physical activity. Per measured risk factors, 34% had central obesity (waist circumference>or=102 cm), 32% had hypertension (>or=140 and/or>or=90 mm Hg), 52% had prehypertension (>or=120 to 139 and/or>or=80 to 89 mm Hg), and 52% had an elevated total cholesterol level (>or=200 mg/dL [5.2 mmol/L]).

STATISTICAL ANALYSES

Multiple linear regression models explaining variability in waist circumference, blood pressure, and serum lipids were tested.

RESULTS

Although preference and intake pairs for fat and sweets were significantly correlated, intake of fat and sweets failed to associate significantly with any risk factor. Significant variance in waist circumference was explained by age, fat preference, fiber intake, and physical activity. Those with greater circumferences liked fat more, consumed less fiber, and exercised less. Waist circumference in turn contributed significantly to models predicting serum lipid levels and blood pressure. Alcohol intake explained variability in serum lipid levels-higher intakes were associated with higher high-density lipoprotein cholesterol levels. The models predicting risk were generally more explanatory in younger (<50 years) than in older men.

CONCLUSIONS

Including a preference measure within an HRA appears to enhance cardiovascular disease risk factor assessment. Fat preference, intake of fiber-rich foods, and alcohol proved the best dietary determinants of cardiovascular disease risk factors.

Okara, soybean residue, prevents obesity in a diet-induced murine obesity model

We examined the effect of okara on the prevention of obesity in mice. A modified AIN-76 diet with a high fat content (14.1% of crude fat) was used as a basal diet. Male ICR mice were fed ad libitum with the basal diet or a dried okara-supplemented basal diet (10, 20, or 40%) for 10 weeks. The okara intake dose-dependently suppressed the development of body weight and epididymal white adipose tissue (EWAT), and prevented an increase of plasma lipids, including total cholesterol, LDL cholesterol, and non-esterified fatty acid. The okara intake also prevented steatosis in the liver. Real-time RT-PCR revealed that the okara intake induced down-regulation of the fatty acid synthetase gene and up-regulation of the cholesterol 7 alpha-hydroxylase (CYP7A1) gene in the liver. We also found that the okara intake caused a marked reduction in the expression of leptin and TNF-alpha genes in EWAT. Our results suggest that okara is beneficial in preventing obesity.

Whole-grain intake is associated with body mass index in college students

OBJECTIVE

To measure whole-grain intake in college students and determine the association with body mass index (BMI).

DESIGN

Cross-sectional convenience sample of college students enrolled in an introductory nutrition course.

SETTING

Large state university.

PARTICIPANTS

159 college students, mean age: 19.9.

MAIN OUTCOME MEASURES

Intake of whole grains, refined grains, calories, and fiber from food records; BMI determined from height and weight measurements.

ANALYSIS

Analysis of variance with linear contrasts; participants grouped by BMI category (P<.05).

RESULTS

Average intake of cereal grains was 5.4 servings per day, of which whole-grain intake accounted for an average of 0.7 servings per day. Whole-grain intake was significantly higher in normal weight students than in overweight and obese students (based on BMI).

CONCLUSIONS AND IMPLICATIONS

The low intake of whole grains in this population of college students indicates the need for interventions aiming to increase whole-grain intake to the recommended minimum of 3 servings per day. College students who are concerned about their body weight may be motivated to increase their intake of whole-grain foods; however, their intake of whole grains is likely to be influenced by the availability of these food items in campus dining halls and other locations around the college campus.

Study protocol of a cluster randomised controlled trial investigating the effectiveness of a tailored energy balance programme for recent retirees

BACKGROUND

People in transitional life stages, such as occupational retirement, are likely to gain weight and accumulate abdominal fat mass caused by changes in physical activity and diet. Hence, retirees are an important target group for weight gain prevention programmes, as described in the present paper.

METHODS/DESIGN

A systematic and stepwise approach (Intervention Mapping) is used to develop a low-intensity energy balance intervention programme for recent retirees. This one-year, low-intensity multifaceted programme aims to prevent accumulation of abdominal fat mass and general weight gain by increasing awareness of energy balance and influencing related behaviours of participants' preference. These behaviours are physical activity, fibre intake, portion size and fat consumption. The effectiveness of the intervention programme is tested in a cluster randomised controlled trial. Measurements of anthropometry, physical activity, energy intake, and related psychosocial determinants are performed at baseline and repeated at 6 months for intermediate effect, at 12 months to evaluate short-term intervention effects and at 24 months to test the sustainability of the effects.

DISCUSSION

This intervention programme is unique in its focus on retirees and energy balance. It aims at increasing awareness and takes into account personal preferences of the users by offering several options for behaviour change. Moreover, the intervention programme is evaluated at short-term and long-term and includes consecutive outcome measures (determinants, behaviour and body composition).

Fiber intake, constipation, and overweight among adolescents living in Sao Paulo City

OBJECTIVE

This study evaluated the dietary fiber intake of adolescents in the metropolitan area of Sao Paulo city and any association between low dietary fiber intake with constipation and overweight.

METHODS

In total, 716 adolescents were included within the study, of whom 314 attended private school and 402 attended public school. Evaluation of fiber intake was based on a 24-h daily intake record and a frequency questionnaire. Data concerning bowel movements and height and weight measurements were also taken.

RESULTS

Fiber consumption, below that recommended ("age + 5"), was found in 61.8% and 41.4% (P = 0.000) of girls attending private and public schools, respectively, and in 44.1% and 25.6% of boys (P = 0.001). Adolescents who did not eat beans on more than 4 d/wk presented a higher risk of fiber intake below that recommended (age + 5; P < 0.05), with odds ratios ranging from 10.4 to 14.2 according gender and private or public schooling. Dietary fiber intake below that recommended was associated with a greater risk (P < 0.05) toward overweight in students attending public schooling (odds ratios 2.84 and 2.95 for males and females, respectively). Low dietary fiber intake was not associated with constipation.

CONCLUSION

Intake of beans more than four times per week is associated with the appropriate level of fiber intake. Dietary fiber intake below the recommendation was not associated with constipation but was associated with being overweight among those students attending public schooling.

Dietary patterns and associated lifestyles in individuals with and without familial history of obesity: a cross-sectional study

Background

Familial history of obesity (FHO) and certain dietary habits are risk factors for obesity. The objectives of this cross-sectional study were 1) to derive dietary patterns using factor analysis in a population of men and women with and without FHO; 2) to compare mean factor scores for each dietary pattern between individuals with and without FHO; and 3) to examine the association between these patterns and anthropometric, lifestyle and sociodemographic variables.

Methods

A total of 197 women and 129 men with a body mass index <30 kg/m² were recruited. A positive FHO (FHO+) was defined as having at least one obese first-degree relative and a negative FHO (FHO-) as no obese first-degree relative. Dietary data were collected from a food frequency questionnaire. Factor analysis was performed to derive dietary patterns. Mean factor scores were compared using general linear model among men and women according to FHO. Regression analyses were performed to study the relationship between anthropometric, lifestyle and sociodemographic variables, and each dietary pattern.

Results

Two dietary patterns were identified in both men and women : the Western pattern characterized by a higher consumption of red meats, poultry, processed meats, refined grains as well as desserts, and the Prudent pattern characterized by greater intakes of vegetables, fruits, non-hydrogenated fat, and fish and seafood. Similar Western and Prudent factor scores were observed in individual with and without FHO. In men with FHO+, the Western pattern is negatively associated with age and positively associated with physical activity, smoking, and personal income. In women with FHO-, the Prudent pattern is negatively associated with BMI and smoking and these pattern is positively associated with age and physical activity.

Conclusion

Two dietary patterns have been identified among men and women with and without FHO. Although that FHO does not seem to influence the adherence to dietary patterns, results of this study suggest that anthropometric, lifestyle and sociodemographic variables associated with dietary patterns differ according to FHO and gender.

Biomedical issues of dietary fiber beta-glucan

Beta-glucan is a polysaccharide in the form of fiber and the main element of fiber in grains such as barley, oats, yeast and mushrooms. Many studies have examined the efficacy of beta-glucan in terms of the lipid lowering effects, blood sugar reduction, weight reduction, immune modulator, and anticarcinogenic effect. However, there is no comprehensive review article on the biomedical issues regarding beta-glucan. The authors searched for systematic reviews and clinical experiments for each relevant topic and reviewed the biomedical effects of beta-glucan, for the purpose of developing research strategies for the future.

Combined effects of maternal smoking status and dietary intake related to weight gain and birth size parameters

OBJECTIVE

To investigate the interaction of smoking status and dietary intake during pregnancy and its relationship to maternal weight gain and birth size parameters.

DESIGN

An observational prospective study.

SETTING

Free-living conditions.

POPULATION

Four hundred and eight healthy pregnant Icelandic women.

METHODS

Maternal smoking status, lifestyle factors and dietary habits were evaluated with questionnaires. Intake of foods and supplements was also estimated with a semiquantitative food frequency questionnaire for the previous 3 months. All questionnaires were filled out between 11 and 15 weeks and between 34 and 37 weeks of gestation. Smoking status in relation to optimal and/or excessive weight gain during pregnancy was represented with logistic regression controlling for potential confounding factors.

MAIN OUTCOME MEASURES

Maternal weight gain, smoking status, dietary intake and birthweight.

RESULTS

Women who smoked throughout pregnancy were unlikely to gain optimal weight or more (OR 0.51, 95% CI 0.27-0.97), whereas smoking cessation in connection with pregnancy ('former smokers') doubled the risk of excessive weight gain (OR 2.03, 95% CI 1.24-3.35). The latter association was no longer significant after adjustment for dietary factors and other confounding factors. Former smokers ate the least amount of fruit and vegetables (fruit: 129 versus 180 and 144 g/day (median), P= 0.038; vegetables: 53 versus 76 and 72 g/day, P= 0.026 for former smokers, nonsmokers and smokers, respectively). Birthweight was lowest among infants born to smokers, but birthweight was similar for former smokers and nonsmokers (3583 +/- 491 g versus 3791 +/- 461 g and 3826 +/- 466 g, respectively; P= 0.003).

CONCLUSIONS

Smoking cessation in early pregnancy or pre-pregnancy is not associated with low birthweight. It is, however, associated with excessive maternal weight gain and a low fruit and vegetable intake.

Arabinoxylan consumption decreases postprandial serum glucose, serum insulin and plasma total ghrelin response in subjects with impaired glucose tolerance

OBJECTIVE

Arabinoxylan (AX) consumption is associated with metabolic improvement during diabetes and with modulation of ghrelin, an orexigenic gut hormone. The effect of AX consumption on ghrelin secretion in disturbed metabolic states is unknown. Therefore, we investigated the postprandial responses to AX consumption of serum glucose, insulin and triglycerides and plasma total and acylated ghrelin in subjects with impaired glucose tolerance (IGT).

DESIGN

Randomized, single-blind, controlled, crossover intervention trial.

SUBJECTS

Seven female and four male adults with IGT, aged 55.5 years, and body mass index (BMI) 30.1 kg/m(2).

INTERVENTION

Subjects received either placebo or 15 g AX supplement for 6 weeks with a 6-week washout period in-between.

MAIN OUTCOME MEASUREMENTS

Postprandial responses of serum glucose, insulin and triglycerides, and plasma total and acylated ghrelin after a liquid meal challenge test (LMCT) measured at the beginning and at the end of the dietary intervention at -20, -5, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 min.

RESULTS

After LMCT, AX consumption resulted in lower postprandial responses in serum glucose, insulin and triglycerides (P<0.05). Compared to placebo, total plasma ghrelin was also reduced by 42+/-8 pg/ml (P<0.001) after AX consumption with no difference in plasma acylated ghrelin.

CONCLUSION

AX consumption improved postprandial metabolic responses after an LMCT in subjects with IGT and reduced total ghrelin response. However, acylated ghrelin responses were unchanged, suggesting that the acylated ghrelin-mediated orexigenic regulation is not improved as only total plasma ghrelin decreased.

Weight loss and long-term follow-up of severely obese individuals treated with an intense behavioral program

OBJECTIVE

To review weight loss and maintenance for severely obese individuals enrolled in intensive behavioral weight loss program using very-low or low-energy diets.

DESIGN

Chart review of consecutively treated patients between 1995 and 2002 seen at three weight loss centers.

SUBJECTS

One thousand five hundred and thirty one patients with severe obesity (>or=40 kg/m(2)) treated in three cities ('Study Group'). Of these, 1100 completed the 12-week core curriculum ('Completer Group'). Weight loss >or=100 lbs (>45 kg) was seen in 268 patients ('100-Pound Group').

MEASUREMENTS

Charts were reviewed for baseline characteristics, weekly weights, follow-up weights and side effects.

RESULTS

In the Study Group, average weight loss+/-s.e. for 998 women was 23.9+/-0.6 kg (18.5% of initial body weight (IBW)) and for 533 men was 36.0+/-1.0 kg (22.5%) over 30 weeks. For Completers, average weight loss for women was 30.8+/-0.6 kg (23.9%) and for men was 42.6+/-1.1 kg (26.7%) over 39 weeks. In the 100-Pound Group, average weight loss for women was 58.2+/-1.2 kg (41.5%) in 65 weeks and for men was 65.7+/-1.5 kg (37.5%) in 51 weeks. Side effects, assessed in 100 patients losing >45 kg, were mild to moderate in severity. Severe adverse events unrelated to the diet were noted in 5% of patients and during weight loss 1% had elective cholecystectomies. Follow-up weights were available for 86% of Completers at an average of 72 weeks with average maintenance of 23 kg or 59% of weight loss; follow-up weights were available for 94% of the 100-Pound Group at an average of 95 weeks with average maintenance of 41 kg or 65% of weight loss maintained.

CONCLUSIONS

Intensive behavioral treatment with meal replacements is a safe and effective weight-loss strategy for selected severely obese individuals.

The effects of fructo-oligosaccharides in combination with soy protein on bone in osteopenic ovariectomized rats

OBJECTIVE

The intestinal microflora is important in rendering soy isoflavones bioavailable by facilitating their conversion to equol. Hence, substances that can modulate the intestinal microflora could affect the bioavailability of isoflavones. In this study, we examined the effects of fructo-oligosaccharides (FOS), a prebiotic, on enhancing the effects of soy isoflavones on bone in ovariectomized osteopenic female rats.

DESIGN

Sixty-three 9-month-old female Sprague-Dawley rats were either sham-operated (Sham; one group) or ovariectomized (Ovx; four groups) and were fed a control diet for 3 months to induce bone loss. After bone loss was confirmed via dual-energy x-ray absorptiometry, rats were placed on dietary treatment for 4 months. The Sham and one Ovx group received a control diet, and the remaining Ovx groups received either a soy protein-based diet (Soy), a FOS-supplemented diet (FOS), or a soy protein-based and FOS-supplemented diet (Soy+FOS). Before the termination of the study, whole-body bone mineral density (BMD) and bone mineral content (BMC) were assessed under anesthesia. Immediately after euthanasia, bone specimens were collected for the assessments of BMD, BMC, and biomechanical and microarchitectural properties.

RESULTS

Whole-body BMD values were significantly higher in FOS and Soy+FOS groups compared with Ovx controls. The tibial BMC increased by 10%, 6%, and 4% in Soy, FOS, and Soy+FOS groups, respectively, compared to the Ovx control group. FOS and FOS+Soy treatments had the most pronounced effects in enhancing lumbar BMC and BMD. The FOS+Soy combination effectively improved tibial microarchitectural properties by enhancing trabecular number and lowering trabecular separation compared with Ovx controls. The effects of dietary treatments on lumbar microarchitectural properties were minimal and biomechanical properties of the femur were not affected by any of the dietary treatments.

CONCLUSION

Our findings suggest that, although incorporation of either soy or FOS in the diet of Ovx rats can improve BMD of the whole body, tibiae, and lumbar vertebrae, their combination had no any additive effects. However, in terms of microarchitecture, the combination of soy and FOS had a greater effect in reversing the loss of certain microarchitectural parameters such as tibial trabecular number, separation, and thickness.

Carob pulp preparation rich in insoluble dietary fiber and polyphenols enhances lipid oxidation and lowers postprandial acylated ghrelin in humans

Ghrelin is an orexigenic hormone that may affect substrate utilization in humans. Ghrelin is influenced by macronutrients, but the effects of insoluble dietary fiber and polyphenols are unknown. We investigated the effects of a polyphenol-rich insoluble dietary fiber preparation from carob pulp (carob fiber) on postprandial ghrelin responses and substrate utilization. Dose-dependent effects of the consumption of carob fiber were investigated in a randomized, single-blind, crossover study in 20 healthy subjects, aged 22-62 y. Plasma total and acylated ghrelin, triglycerides, and serum insulin and nonesterified fatty acids (NEFA) levels were repeatedly assessed before and after ingestion of an isocaloric standardized liquid meal with 0, 5, 10, or 20 g of carob fiber over a 300-min period. The respiratory quotient (RQ) was determined after consumption of 0 or 20 g of carob fiber. Carob fiber intake lowered acylated ghrelin to 49.1%, triglycerides to 97.2%, and NEFA to 67.2% compared with the control meal (P < 0.001). Total ghrelin and insulin concentrations were not affected by consumption of a carob fiber-enriched liquid meal. Postprandial energy expenditure was increased by 42.3% and RQ was reduced by 99.9% after a liquid meal with carob fiber compared with a control meal (P < 0.001). We showed that the consumption of a carob pulp preparation, an insoluble dietary fiber rich in polyphenols, decreases postprandial responses of acylated ghrelin, triglycerides, and NEFA and alters RQ, suggesting a change toward increased fatty acid oxidation. These results indicate that carob fiber might exert beneficial effects in energy intake and body weight.

Relation between colonic proglucagon expression and metabolic response to oligofructose in high fat diet-fed mice

Several data suggest that fermentable dietary fiber could play a role in the control of obesity and associated metabolic disorders. The aim of this study was to investigate the putative role of short chain fructo-oligosaccharide (OFS) - a non-digestible oligosaccharide - in mice fed a standard diet and in mice fed two distinct high fat diets inducing metabolic disorders associated to obesity. We confirmed, in mice, several effects previously shown in rats fed a standard diet enriched with OFS, namely an increase in total and empty caecum weight, a significant decrease in epididymal fat mass, and an increase in colonic and portal plasma glucagon-like peptide-1 (GLP-1), a phenomenon positively correlated with a higher colonic proglucagon mRNA level. Curiously, 4-week treatment with OFS added at the same dose induced different effects when added in the two different high fat diets. OFS decreased energy intake, body weight gain, glycemia, and epididymal fat mass only when added together with the high fat-carbohydrate free diet, in which OFS promoted colonic proglucagon expression and insulin secretion. Our results support an association between the increase in proglucagon expression in the proximal colon and OFS effects on glycemia, fat mass development, and/or body weight gain. In conclusion, dietary oligosaccharides would constitute an interesting class of dietary fibers promoting, in certain conditions, endogenous GLP-1 production, with beneficial physiological consequences. This remains to be proven in human studies.

Consumption of pork-liver protein hydrolysate reduces body fat in Otsuka Long-Evans Tokushima Fatty rats by suppressing hepatic lipogenesis

This study was performed to examine the effect of consumption of pork-liver protein hydrolysate (PLH) on body fat accumulation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a non-insulin-dependent diabetes mellitus model and in Long-Evans Tokushima Otsuka (LETO) rats as a control. Male 20-week-old OLETF and LETO rats were pair-fed either PLH or casein containing diet for 14 weeks. In the OLETF rats, dietary PLH significantly reduced the growth and weight of fat pad including perirenal and epididymal adipose tissues. Consumption of PLH markedly suppressed hepatic activities of lipogenesis enzymes such as glucose-6-phosphate dehydrogenase and fatty acid synthase and slightly elevated fecal excretion of total fat. In the LETO rats, growth and adipose tissue weight were unaffected by dietary treatment. The results suggest that PLH is a novel ingredient suppressing body fat in genetically obese rats by reducing lipogenesis.

Obesity: prevalence, theories, medical consequences, management, and research directions

Obesity and its associated disorders are a growing epidemic across the world. Many genetic, physiological, and behavioral factors play a role in the etiology of obesity. Diet and exercise are known to play a valuable role in the treatment and prevention of obesity and associated disorders such as hypertension, heart disease, and diabetes. Therefore, the purpose of this review is to examine the prevalence, etiology, consequences, and treatment of obesity.

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.