Dietary fiber and cardiovascular disease: experimental and epidemiologic advances

Low-carbohydrate diet and cardiovascular diseases in Iranian population: Tehran Lipid and Glucose Study

BACKGROUND AND AIMS

Studies indicated that the risk of cardiovascular disease (CVD) in association to greater adherence to low-carbohydrate diet (LCD) differs in various populations. In this study, we aimed to assess the association of LCD score with the risk of CVD events in a prospective population-based study.

METHODS AND RESULTS

CVD-free participants (n = 2188) were recruited from the Tehran Lipid and Glucose Study (2006-2008) and followed for a mean of 6.7 years. Using a valid and reliable 168 item semi-quantitative food frequency questionnaire, the LCD score was determined based on the percentage of energy as carbohydrate, protein, and fat, which ranged from 0 to 12. Cox proportional hazard regression models, adjusted for potential confounders, were used to estimate the hazard ratios (HRs) and 95% confidence interval (CI) of CVD across tertiles of LCD score in women and men. Mean ± SD age of participants (44.8% male) was 38.8 ± 13.0 years, and median (25-75, interquartile range) of the LCD score was 6 (4-8) at baseline. During follow-up, 77 (3.5%) new cases of CVD were identified. After adjustment for sex, age, body mass index, physical activity, smoking, energy intake, diabetes, and hypertension, there was no association between the LCD score and risk of CVD outcomes in all participants (HR = 0.93; 95% CI: 0.86-1.02) and women (HR = 1.13; 95% CI: 0.94-1.36); however, the LCD score was associated with an 11% reduced incidence of CVD events in men (HR = 0.89; 95% CI: 0.80-0.98), (P for trend: 0.028).

CONCLUSION

Findings showed that higher adherence to LCD may be associated with a lower risk of CVD outcomes in men but not in women.

Intake of legumes and the risk of cardiovascular disease: frailty modeling of a prospective cohort study in the Iranian middle-aged and older population

BACKGROUND/OBJECTIVES

The purpose of this study was to explore the association of legume intake (beans, chickpeas, lentils and so on), as part of a low-glycemic index diet, with the risk of cardiovascular events in the Iranian middle- and old-aged people.

SUBJECTS/METHODS

A total of 6504 subjects living in the three counties of Iran participated in the Isfahan Cohort Study. Totally, 6323 were free of cardiovascular disease (CVD) at their baseline examination. Of the 6323 individuals, 5398 participants remained in the study for 7 years of follow-up. They have been contacted every 2 years for possible occurrence of CVD events including fatal and non-fatal myocardial infarction, unstable angina, fatal and non-fatal stroke, and sudden cardiac death. The frequency of legume intake was estimated using a food frequency questionnaire. Cox proportional hazards models with shared gamma frailty terms were used to model time to event outcomes.

RESULTS

After a median follow-up of 6.8 years, 427 cardiovascular events occurred. The intake of legumes in different tertiles of consuming measure was associated with 34% lower risk of CVD in old-aged people, after controlling for the other probable confounders (hazard ratio and 95% CI: 0.66 (0.45, 0.98), P-value=0.039). However, there was no significant association between the frequency of consuming legumes and CVD events in the middle-aged people.

CONCLUSIONS

The present study indicated a strong inverse relationship between legume intake and the risk of cardiovascular events in old-aged Iranian people.

The combined impact of adherence to five lifestyle factors on all-cause, cancer and cardiovascular mortality: a prospective cohort study among Danish men and women

Individual lifestyle factors have been associated with lifestyle diseases and premature mortality by an accumulating body of evidence. The impact of a combination of lifestyle factors on mortality has been investigated in several studies, but few have applied a simple index taking national guidelines into account. The objective of the present prospective cohort study was to investigate the combined impact of adherence to five lifestyle factors (smoking, alcohol intake, physical activity, waist circumference and diet) on all-cause, cancer and cardiovascular mortality based on international and national health recommendations. A Cox proportional hazards model was used to estimate hazard ratios (HR) with 95 % CI. During a median follow-up of 14 years, 3941 men and 2827 women died. Among men, adherence to one additional health recommendation was associated with an adjusted HR of 0·73 (95 % CI 0·71, 0·75) for all-cause mortality, 0·74 (95 % CI 0·71, 0·78) for cancer mortality and 0·70 (95 % CI 0·65, 0·75) for cardiovascular mortality. Among women, the corresponding HR was 0·72 (95 % CI 0·70, 0·75) for all-cause mortality, 0·76 (95 % CI 0·73, 0·80) for cancer mortality and 0·63 (95 % CI 0·57, 0·70) for cardiovascular mortality. In the present study, adherence to merely one additional health recommendation had a protective effect on mortality risk, indicating a huge potential in enhancing healthy lifestyle behaviours of the population.

Dietary compliance, dietary supplementation and traditional remedy usage of type 2 diabetic patients with and without cardiovascular disease

This analytical cross-sectional study examined the nutrient intakes, dietary compliance, dietary supplementation and traditional remedy usage in type 2 diabetes mellitus (T2DM) patients from selected tertiary hospitals in multi-racial Malaysia. We compared the different characteristics of T2DM patients with and without cardiovascular disease (CVD). Socio-demographic status, dietary intakes, dietary supplementation, traditional remedy use, medical history, anthropometric measurements and clinical characteristics were obtained from face-to-face interviews. A total of 313 patients who were treated for T2DM participated in this study, in which 36.1% of them had CVD. The mean age of study subjects was 55.7 ± 9.2 years; mean diabetes duration was 10.1 ± 8.1 years; 52.1% were females; and 47.0% were Malays. The mean total energy intake of the subjects was 1674 ± 694 kcal/day, and patients with CVD consumed higher total calories (p = 0.001). Likewise, the mean carbohydrate, protein and total fat intake of CVD patients were significantly higher than non-CVD patients (p < 0.05), while mean intakes of cholesterol, fibre, minerals and all vitamins were comparable between CVD and non-CVD patients. Regardless of CVD status, a notably high proportion of the subjects did not meet the recommendations of the Medical Nutrition Therapy Guidelines for Type 2 Diabetes for total energy, carbohydrate, protein, total fat, and fibre intakes. Meanwhile, 52.4% used at least one dietary supplement and 12.1% took single traditional remedy or in various combinations. Traditional remedies and supplement intake did not differ between CVD and non-CVD subjects. It is suggested that T2DM patients should be educated based on their personalized dietary intake, dietary supplementation and traditional remedy usage. The recommendations for T2DM patients shall be met to achieve the optimal metabolic goals and minimize the potential diabetic complications.

Effects of in utero conditions on adult feeding preferences

The fetal or early origins of adult disease hypothesis states that environmental factors, particularly nutrition, act in early life to program the risks for chronic diseases in adult life. As eating habits can be linked to the development of several diseases including obesity, diabetes and cardiovascular disease, it could be proposed that persistent food preferences across the life-span in people who were exposed to an adverse fetal environment may partially explain their increased risk to develop metabolic disease later in life. In this paper, we grouped the clinical and experimental evidence demonstrating that the fetal environment may impact the individual's food preferences. In addition, we review the feeding preferences development and regulation (homeostatic and hedonic pathways, the role of taste/olfaction and the reward/pleasure), as well as propose mechanisms linking early life conditions to food preferences later in life. We review the evidence suggesting that in utero conditions are associated with the development of specific food preferences, which may be involved in the risk for later disease. This may have implications in terms of public health and primary prevention during early ages.

Traditional risk factor management for stroke: a never-ending challenge for health behaviors of diet and physical activity

PURPOSE OF REVIEW

Recently, many guidelines have given new evidence on the risk factors for stroke. In this review, I refer to the most important guidelines for primary prevention of stroke and hypertension, especially focused on diet and physical activity.

RECENT FINDINGS

The health behavior recommendations in recent guidelines for the primary prevention of stroke are virtually identical, and the same recommendations appear in the recent guidelines for the management of hypertension, especially with respect to diet and physical activity. The recommended health behaviors consist of weight reduction, reduction of salt intake, increase in fruit and vegetable intake, decrease in saturated and total fat intake (increase in fish intake), physical activity, and moderation of alcohol consumption. Fruits and vegetables have high levels of potassium, antioxidants, phytochemicals, and dietary fiber, and thus are also considered preventive of cardiovascular disease and its risk factors. It was found that individuals with many of these health behaviors have been shown to have a lowered risk of stroke.

SUMMARY

The health behaviors, especially those related to diet and physical activity, appearing in recent guidelines for the management of hypertension are also important for the primary prevention of stroke, and appear in recent stroke guidelines.

Dietary fiber intake and risk of cardiovascular disease in the Japanese population: the Japan Public Health Center-based study cohort

BACKGROUND/OBJECTIVES

There has been no study with regard to the association between dietary fibers and the incidence of stroke and coronary heart disease (CHD) in Asia. We investigated the association between dietary fiber and the risk of cardiovascular disease (CVD), which we defined as stroke or CHD, in a Japanese population.

SUBJECTS/METHODS

We studied 86 387 Japanese subjects (age 45-65 years, without CVD or cancer in 1995 as Cohort I and in 1998 as Cohort II) and used a self-administered questionnaire to follow-up the participants until the end of 2004. Dietary fiber intake was estimated from food-frequency questionnaires comprising 138 food items.

RESULTS

After 899 141 person-years of follow-up, we documented the incidence of 2553 strokes and 684 cases of CHD. Multivariable-adjusted hazard ratios (95% confidence intervals (CIs)) of CVD for the third to fifth quintiles of total fiber were 0.79 (0.63-0.99), 0.70 (0.54-0.89) and 0.65 (0.48-0.87) in women, respectively, compared with the lowest quintile. Total fiber intake was inversely associated with the incidence of stroke, either cerebral infarction or intracerebral hemorrhage in women. The results for insoluble fiber in women were similar to those for total fiber, whereas those for soluble fiber were weak. An inverse association of total fiber with CVD was observed primarily in non-smokers (P for trend=0.045 and 0.001) and not in smokers (probability values for interaction between total fiber and smoking were 0.06 and 0.01 in men and women, respectively).

CONCLUSIONS

Higher total dietary fiber was associated with reduced risk of CVD in Japanese non-smokers.

Dietary fiber is associated with circulating concentrations of C-reactive protein in breast cancer survivors: the HEAL study

Inflammation is a suspected risk factor for breast cancer and its subsequent prognosis. The extent to which dietary and lifestyle factors might influence inflammation is important to examine. Specifically, dietary fiber may reduce systemic inflammation, but this relationship has not been examined among breast cancer survivors. We examined associations between dietary fiber and serum concentrations of C-reactive protein (CRP) and serum amyloid A (SAA), among 698 female breast cancer survivors from the Health, Eating, Activity, and Lifestyle (HEAL) Study. Data are from interviews and clinical visits conducted 24-months post-study enrollment. Multivariate-adjusted linear regression estimated associations of total, soluble, and insoluble fiber with serum concentrations of CRP and SAA. Logistic regression estimated the odds of elevated CRP (defined as >3.0 mg/l) across tertiles of dietary fiber intake. Mean total dietary fiber intake was 13.9 ± 6.4 g/day. Mean CRP and SAA were 3.32 ± 3.66 and 7.73 ± 10.23 mg/l, respectively. We observed a multivariate-adjusted inverse association between total dietary fiber intake and CRP concentrations (β, -0.029; 95% CI, -0.049, -0.008). Results for insoluble fiber were similar (β, -0.039; 95% CI, -0.064, -0.013). Among survivors who consumed >15.5 g/day of insoluble dietary fiber, a 49% reduction in the likelihood of having elevated CRP concentrations (OR, 0.51; 95% CI, 0.27, 0.95) was observed compared to those who consumed <5.4 g/day (P = 0.053). Our results suggest that diets high in fiber may benefit breast cancer survivors via reductions in systemic inflammation; elevated inflammation may be prognostic for reduced survival.

[Critical analysis of the American Diabetes Association dietary recommendations for cardiovascular disease in diabetes mellitus]

Cardiovascular disease (CVD) is the main cause of mortality among patients with diabetes mellitus (DM), and dietary intervention is an essential measure to prevent and treat this complication. The aim of this manuscript was to review scientific evidence that underlies the dietetic recommendations of the American Diabetes Association (ADA) for prevention and treatment of CVD in patients with DM. The ADA guidelines are mostly based on studies performed on patients with CVD and without DM. The evidence-based dietary recommendations for patients with DM are to increase the intake of fish and soluble fibers. Although DM has been considered as an equivalent of established CVD, the adoption of the same dietary recommendations for patients without DM and with CVD for all patients with DM is still questionable -- especially considering the peculiarities of CVD in DM. Randomized clinical trials including patients with DM should provide further information regarding the benefits of these dietary interventions for CVD.

Dietary fiber intake is associated with reduced risk of mortality from cardiovascular disease among Japanese men and women

Dietary fiber protects against coronary heart disease (CHD), but evidence in Asia is limited. We examined the association between dietary fiber intake and mortality from cardiovascular disease (CVD) in a Japanese population in a prospective study of 58,730 Japanese men and women aged 40-79 y in which dietary fiber intake was determined by a self-administered FFQ. The participants were followed up from 1988-1990 to the end of 2003. Hazard ratios (HR) and 95% CI of mortality were calculated per quintile of fiber intake. During the 14-y follow-up, a total of 2080 CVD deaths (983 strokes, 422 CHD, and 675 other CVD) were documented. Total, insoluble, and soluble dietary fiber intakes were inversely associated with risk of mortality from CHD and total CVD for both men and women. For men, the multivariable HR (95% CI) for CHD in the highest vs. the lowest quintiles were 0.81 [(95% CI, 0.61-1.09); P-trend = 0.02], 0.48 [(95% CI, 0.27-0.84); P-trend < 0.001], and 0.71 [(95% CI, 0.41-0.97); P-trend = 0.04] for total, insoluble, and soluble fiber, respectively. The respective HR (95% CI) for women were 0.80 [(95% CI, 0.57-0.97); P-trend = 0.01], 0.49 [(95% CI, 0.27-0.86); P-trend = 0.004], and 0.72 [(95% CI, 0.34-0.99); P-trend = 0.03], respectively. For fiber sources, intakes of fruit and cereal fibers but not vegetable fiber were inversely associated with risk of mortality from CHD. In conclusion, dietary intakes of fiber, both insoluble and soluble fibers, and especially fruit and cereal fibers, may reduce risk of mortality from CHD.

Preventing and managing cardiometabolic risk: the logic for intervention

Cardiometabolic risk (CMR), also known as metabolic syndrome or insulin resistance syndrome, comprises obesity (particularly central or abdominal obesity), high triglycerides, low HDL, elevated blood pressure, and elevated plasma glucose. Leading to death from diabetes, heart disease, and stroke, the root cause of CMR is inadequate physical activity, a Western diet identified primarily by low intake of fruits, vegetables, and whole grains, and high in saturated fat, as well as a number of yet-to-be-identified genetic factors. While the pathophysiological pathways related to CMR are complex, the universal need for adequate physical activity and a diet that emphasizes fruits and vegetables and whole grains, while minimizing food high in added sugars and saturated fat suggests that these behaviors are the appropriate focus of intervention.

Dietary fiber intake in relation to coronary heart disease and all-cause mortality over 40 y: the Zutphen Study

BACKGROUND

Little is known about the effects of dietary fiber intake on long-term mortality.

OBJECTIVE

We aimed to study recent and long-term dietary fiber intake in relation to coronary heart disease and all-cause mortality.

DESIGN

The effects of recent and long-term dietary fiber intakes on mortality were investigated in the Zutphen Study, a cohort of 1,373 men born between 1900 and 1920 and examined repeatedly between 1960 and 2000. During that period, 1,130 men died, 348 as a result of coronary heart disease. Hazard ratios were obtained from time-dependent Cox regression models.

RESULTS

Every additional 10 g of recent dietary fiber intake per day reduced coronary heart disease mortality by 17% (95% CI: 2%, 30%) and all-cause mortality by 9% (0%, 18%). The strength of the association between long-term dietary fiber intake and all-cause mortality decreased from age 50 y (hazard ratio: 0.71; 95% CI: 0.55, 0.93) until age 80 y (0.99; 0.87, 1.12). We observed no clear associations for different types of dietary fiber.

CONCLUSIONS

A higher recent dietary fiber intake was associated with a lower risk of both coronary heart disease and all-cause mortality. For long-term intake, the strength of the association between dietary fiber and all-cause mortality decreased with increasing age.

Dietary fiber, lung function, and chronic obstructive pulmonary disease in the atherosclerosis risk in communities study

Recent data suggest beneficial effects of fiber intake on chronic respiratory symptoms in adults that are independent of antioxidant vitamin intake, but little is known about fiber consumption in relation to lung function and chronic obstructive pulmonary disease (COPD). The authors investigated the association of fiber intake with lung function and COPD in 11,897 US men and women from the Atherosclerosis Risk in Communities study (1987-1989). After control for potential confounders, positive associations were found between lung function and fiber intake from all sources as well as from cereal or fruit alone. Compared with those in the lowest quintile, participants in the highest quintile of total fiber intake had a 60.2-ml higher forced expiratory volume in 1 second (FEV(1)) (p for trend < 0.001), 55.2-ml higher forced vital capacity (FVC) (p = 0.001), 0.4% higher FEV(1)/FVC ratio (p = 0.040), 1.8% higher percent predicted FEV(1) (p < 0.001), and 1.4% higher percent predicted FVC (p = 0.001). Adjusted odds ratios of COPD for the highest versus lowest quintiles of intake were 0.85 (p = 0.044) for total fiber, 0.83 (p = 0.021) for cereal fiber, and 0.72 (p = 0.005) for fruit fiber. This study provides the first known evidence that dietary fiber is independently associated with better lung function and reduced prevalence of COPD.

Dietary fiber intake and retinal vascular caliber in the Atherosclerosis Risk in Communities Study

BACKGROUND

Dietary fiber appears to decrease the risk of cardiovascular morbidity and mortality. Microvascular abnormalities can be observed by retinal examination and contribute to the pathogenesis of various cardiovascular diseases. The impact of dietary fiber on the retinal microvasculature is not known.

OBJECTIVE

We aimed to examine the association between dietary fiber intake and retinal vascular caliber.

DESIGN

At the third visit (1993-1995) of the Atherosclerosis Risk in Communities (ARIC) Study, a population-based cohort of adults in 4 US communities, the retinal vascular caliber of 10,659 participants was measured and summarized from digital retinal photographs. Usual dietary intake during the same period was assessed with a 66-item food-frequency questionnaire.

RESULTS

After control for potential confounders including hypertension, diabetes, lipids, demographic factors, cigarette smoking, total energy intake, micronutrients intake, and other cardiovascular disease risk factors, higher intake of fiber from all sources and from cereal were significantly associated with wider retinal arteriolar caliber and narrower venular caliber. Participants in the highest quintile of fiber intake from all sources had a 1.05-microm larger arteriolar caliber (P for trend = 0.012) and a 1.11-microm smaller venular caliber (P for trend = 0.029).

CONCLUSIONS

Dietary fiber was related to wider retinal arteriolar caliber and narrower venular caliber, which are associated with a lower risk of cardiovascular disease. These data add to the growing evidence of the benefits of fiber intake on various aspects of cardiovascular pathogenesis.

Associations between dietary pattern and lifestyle, anthropometry and other health indicators in the elderly participants of the EPIC-Italy cohort

INTRODUCTION

Epidemiological studies have shown that dietary behaviour is an important aetiological factor in various chronic diseases. We used principal component factor analysis to identify dietary patterns and to examine the associations of these patterns with health-related variables in a sample of elderly (> or =60 years) Italians participating in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS AND RESULTS

Exploratory factor analysis was applied to the intake of food groups as estimated by semi-quantitative food questionnaires. Individual participants were assigned factor scores, indicating the extent to which their diet conformed to each of the four dietary patterns identified: prudent (cooked vegetables, pulses, cabbage, seed oil and fish); pasta & meat (pasta, tomato sauce, red meat, processed meat, bread and wine); olive oil & salad (raw vegetables, olive oil, soup and chicken); and sweet & dairy (sugar, cakes, ice cream, coffee and dairy). Highly educated people had high scores on prudent and low scores on pasta & meat. The pasta & meat and prudent patterns were strongly positively associated with body mass index (BMI) and waist-to-hip ratio (WHR) in men and women. Hyperlipidaemic men and women consumed more of the prudent and olive oil & salad patterns and less of the sweet & dairy pattern than those with normal lipids. The olive oil & salad was significantly higher and the pasta & meat and sweet & dairy patterns significantly lower in men and women who had dieted over the previous year, suggesting awareness of the health consequences of these patterns.

CONCLUSIONS

Dietary pattern analysis provides a characterization of recurrent dietary behaviour in elderly people, and can be used to provide tangible dietary advice to elderly people.

Whole grain intake and cardiovascular disease: A review

Prospective epidemiologic and feeding studies find possible health benefits of whole cereal grain foods (which include the bran, germ, and endosperm in their naturally occurring proportions), especially for prevention of atherosclerotic cardiovascular diseases and type 2 diabetes. We review 17 articles that consistently found a 20% to 40% reduction in long-term risk of these diseases comparing habitual consumers of whole grains to those who rarely eat these foods. Another 12 studies found a similar risk reduction according to amount of cereal fiber consumed. Feeding studies show improvements in risk factors for these diseases when whole grain foods are consumed. Some authors have tried to explain the reduced risk by invoking cereal fiber, with no attention to nonfiber constituents. We interpret the data as supportive of a synergy of the whole grain constituents, including fiber as only one such constituent.

Dietary fiber and C-reactive protein: findings from national health and nutrition examination survey data

A higher intake of dietary fiber may decrease the risk of developing cardiovascular disease. We examined the association between dietary fiber and serum concentration of C-reactive protein (CRP), a possible predictor of cardiovascular events, using data from the National Health and Nutrition Examination Survey 1999-2000. Among 3920 participants > or = 20 y old, dietary fiber intake was inversely associated with serum CRP concentration. The odds ratio (OR) for increased CRP concentration (>3.0 mg/L) was 0.49 (95% CI 0.37-0.65; P for trend < 0.001) for the highest quintile of fiber intake compared with the lowest. Adjustment for age, gender, race, education, smoking, physical activity, BMI, total energy, and fat intake resulted in a slight attenuation (OR 0.59; CI 0.41-0.85; P for trend = 0.006). Excluding participants with cardiovascular conditions, diabetes, or cancer did not alter the results. Our findings indicate that fiber intake is independently associated with serum CRP concentration and support the recommendation of a diet with a high fiber content.

Becoming Proactive With the Whole-Grains Message

Whole-grain foods have always been considered a healthy part of the diet. Only recently have epidemiologic and other data shown that whole grains have a role in preventing cardiovascular disease, diabetes, some types of cancer, and even obesity. What nearly all consumers and most health professionals fail to realize is that whole grains deliver as many if not more phytochemicals and antioxidants than do fruits and vegetables. Healthy People 2010 (DHHS) recommends 3 servings of whole grains per day. Because the average intake in the United States is less than 1 serving per day, health professionals must mount an active campaign to help consumers better understand the important health benefits of whole grains and work to increase their intake in the diet.

Randomised controlled short-term intervention pilot study on rye bran bread in prostate cancer

The short-term effects of rye bran bread intake in prostate cancer were investigated. Ten men with conservatively treated prostate cancer were randomised to a daily supplement of 295 g of rye bran bread and eight men to 275 g of wheat bread (control) with similar fibre content for three weeks. Blood samples, ultrasound-guided core biopsies of the prostate, and urine samples were taken. In the rye group, there was a significant increase in plasma enterolactone, and the apoptotic index increased significantly from 2.1% (SD 1.3) to 5.9% (SD 1.8), P<0.005 as measured by a TUNEL index in four cases in the rye group and seven cases in the control group. Besides a significant decrease in weight in both groups, only small changes were observed in plasma concentrations of prostate specific antigen (PSA), circulating sex hormones, excreted oestrogens, insulin-like growth factor (IGF)-I, and in the endothelial fibrinolytical system. High intake of rye bran bread is suggested to increase apoptosis in prostate tumours.

Types of carbohydrates and risk of cardiovascular disease

The purpose of this review is to provide an overview of the role of dietary carbohydrates in the etiology of cardiovascular disease (CVD) among women. Many factors are thought to affect insulin resistance, and little is known about the role of diet. Through effects on postprandial glucose and insulin, dietary glycemic load may have an important role in the insulin resistance syndrome (IRS). Dietary fiber, through its influence on the glycemic load or through other pathways, may also have important effects on this syndrome. Many short-term experimental studies have supported these hypotheses. Interestingly, associations may be stronger among overweight individuals than among nonoverweight individuals. Similar to findings for fruits and vegetables, whole grain intake has been found to be consistently associated with a reduction in risk of coronary heart disease (CHD) among both men and women. Several large randomized trials of primary and secondary prevention to date have demonstrated the efficacy of diets based on an abundance of plant foods and, therefore, high carbohydrate quality. The recommendations to follow a diet including an abundance of fiber-rich foods in order to prevent CVD and diabetes are based on a wealth of consistent scientific evidence. More long-term controlled trials are needed to improve our understanding of efficacy and mechanisms. Women and a variety of racial/ethnic groups should be represented in these studies whenever possible.

Dietary fiber and body-weight regulation. Observations and mechanisms

Dietary fiber may be related to body-weight regulation through plausible physiologic mechanisms that have considerable support in the scientific literature. Many short-term studies suggest that high-fiber foods induce greater satiation and satiety. Epidemiologic studies generally [figure: see text] support a role for fiber in body-weight regulation among free-living individuals consuming self-selected diets, although conclusive intervention studies addressing this point are lacking. Thus, there is considerable reason to conclude that fiber-rich diets, containing non-starchy vegetables, fruits, whole grains, legumes, and nuts, may be effective in the prevention and treatment of obesity in children. Such diets may have additional benefits, independent of changes in adiposity, in the prevention of cardiovascular disease and type 2 diabetes.