The role of whole grains in body weight regulation

Utilization of plant-based foods for effective prevention of chronic diseases: a longitudinal cohort study

The present study examined optimal dietary patterns of eight plant-based foods for preventing chronic diseases, including hypertension, stroke, myocardial infarction, and diabetes, using data from the China Health and Nutrition Survey (CHNS). We applied generalized estimating equations to assess time-based changes and gender differences, using residual balancing weights to control time-varying confounders, and employed a restricted cubic spline model to explore dose-response relationships by gender. The findings suggested that a high intake of vegetables and whole grains, along with moderate amounts of fruits, fungi and algae, could help reduce the risk of developing these four chronic diseases simultaneously. Additionally, men could benefit from moderate refined grain consumption, while women should consider increasing their intake of nuts and seeds. Our results indicated that adopting a plant-based diet could provide non-linear protective effects against chronic diseases, with the magnitude of this protection varying by gender.

Impact of sleep duration and dietary patterns on risk of metabolic syndrome in middle-aged and elderly adults: a cross-sectional study from a survey in Anhui, Eastern China

The aim of this study was to assess the sleep status of middle-aged and elderly adults in Bengbu City, Anhui Province, China, to identify the major dietary patterns, and to analyze the association of different sleep duration and dietary patterns with metabolic syndrome (MetS) and its related influencing factors, as well as to explore the predictive value of sleep duration and dietary patterns. A cross-sectional analysis was performed utilizing data collected from the Community-based Cardiovascular and Health Promotion Study 2019 (COCHPS 2019) conducted in Bengbu. The definition of MetS adhered to the criteria of Guidelines for the Prevention and Treatment of Dyslipidemia in Chinese Adults (2016 Revision). Dietary information was obtained using the Food Frequency Questionnaire (FFQ) to assess dietary intake over the past year. Principal component analysis (PCA) was performed to identify dominant dietary patterns. A logistic regression model was developed to analyze the associations among sleep duration, dietary patterns, and MetS, and a decision tree (DT) model was developed to compare factors affecting MetS and screen people at high risk for MetS. The prevalence of MetS was 13.4% among the 9132 middle-aged and elderly residents over 45 years of age included in COCHPS 2019. Participants were divided into short (< 6 h/d), normal (6-8 h/d), and long (> 8 h/d) groups based on their daily sleep duration. Three dietary patterns were identified by PCA, the fruit-milk pattern, the tubers-meat pattern, and the vegetable-cereal pattern. After adjusting for covariables, logistic regression analysis showed that long sleep duration was significantly negatively associated with MetS. The fruit-milk and vegetable-cereal patterns were negatively associated with MetS, whereas the tubers-meat pattern was positively correlated with MetS. The results of the DT model analysis showed that the vegetable-cereal pattern is the most important factor impacting MetS, followed by marital status, the tubers-meat pattern, the fruit-milk pattern, exercise, sleep duration, and gender. The DT model also screened out five types of MetS high-risk groups. The results of our study indicate that normal sleep duration and consumption of either a fruit-milk or vegetable-cereal diet may lower the likelihood of developing MetS in middle-aged and elderly adults.

The regulation of glucose and lipid metabolism through the interaction of dietary polyphenols and polysaccharides via the gut microbiota pathway

The interaction of polyphenols-polysaccharides-gut microbiota to promote health benefits has become a hotspot and direction for precise dietary intervention strategies and foundational research in biomedicine. Both dietary polyphenols and polysaccharides possess biological activities that regulate body health. Single components, due to their inherent structure and physicochemical properties, have a low bioavailability, thus are unable to exert their optimal effects. The compound structure formed by the interaction of polyphenols and polysaccharides can enhance their functional properties, thereby more effectively promoting health benefits and preventing diseases. This review primarily focuses on the roles played by polyphenols and polysaccharides in regulating glucose and lipid metabolism, the improvement of glucose and lipid metabolism through the gut microbial pathway by polyphenols and polysaccharides, and the mechanisms by which polyphenols and polysaccharides interact to regulate glucose and lipid metabolism. A considerable amount of preliminary research has confirmed the regulatory effects of plant polyphenols and polysaccharides on glucose and lipid metabolism. However, studies on the combined effects and mechanisms of these two components are still very limited. This review aims to provide a reference for subsequent research on their interactions and changes in functional properties.

Association between Whole-Grain Intake and Obesity Defined by Different Anthropometric Indicators and Dose-Response Relationship Analysis among U.S. Adults: A Population-Based Study

Existing research shows an inconsistent correlation between whole-grain intake and obesity risk, with limited study on the dose-response relationship. Here, we aimed to examine this association and dose-response relationship among U.S. adults who participated in a NHANES (2003-2018). The intake of whole grain was collected and calculated from two rounds of 24 h dietary recall. Obesity was categorized based on body mass index (BMI) and waist circumference (WC). Weighted multivariable logistic regression models were used to calculate the odds of obesity according to whole-grain intake, and the dose-response relationship was modeled by restricted cubic spline regression. Among the 27,862 participants, 38.3% had general obesity, while 58.3% had abdominal obesity. After multivariate adjustment of potential confounders, the participants in the highest quintile of whole-grain intake had a lower prevalence of general obesity (OR 0.79; 95% CI 0.72-0.88) and abdominal obesity (OR 0.80; 95% CI 0.73-0.89) compared with those in the lowest category. Spline regression showed an inversely linear dose-response association between whole-grain intake and the prevalence of general obesity and abdominal obesity. In conclusion, a higher whole-grain intake was associated with lower odds of obesity, both general and abdominal. Our findings highlight the importance of increasing the whole-grain intake to prevent and manage obesity.

Comprehensive Strategies for Metabolic Syndrome: How Nutrition, Dietary Polyphenols, Physical Activity, and Lifestyle Modifications Address Diabesity, Cardiovascular Diseases, and Neurodegenerative Conditions

Several hallmarks of metabolic syndrome, such as dysregulation in the glucose and lipid metabolism, endothelial dysfunction, insulin resistance, low-to-medium systemic inflammation, and intestinal microbiota dysbiosis, represent a pathological bridge between metabolic syndrome and diabesity, cardiovascular, and neurodegenerative disorders. This review aims to highlight some therapeutic strategies against metabolic syndrome involving integrative approaches to improve lifestyle and daily diet. The beneficial effects of foods containing antioxidant polyphenols, intestinal microbiota control, and physical activity were also considered. We comprehensively examined a large body of published articles involving basic, animal, and human studie, as well as recent guidelines. As a result, dietary polyphenols from natural plant-based antioxidants and adherence to the Mediterranean diet, along with physical exercise, are promising complementary therapies to delay or prevent the onset of metabolic syndrome and counteract diabesity and cardiovascular diseases, as well as to protect against neurodegenerative disorders and cognitive decline. Modulation of the intestinal microbiota reduces the risks associated with MS, improves diabetes and cardiovascular diseases (CVD), and exerts neuroprotective action. Despite several studies, the estimation of dietary polyphenol intake is inconclusive and requires further evidence. Lifestyle interventions involving physical activity and reduced calorie intake can improve metabolic outcomes.

The effects of quinoa bran dietary fiber on glucose and lipid metabolism and hepatic transcriptome in obese rats

BACKGROUND

As a complex chronic metabolic disease, obesity not only affects the quality of human life but also increases the risk of various other diseases. Therefore, it is important to investigate the molecular mechanisms and therapeutic effects of dietary interventions that counteract obesity.

RESULTS

In this study, we extracted soluble (SDF) and insoluble dietary fiber (IDF) from quinoa bran using an enzymatic method and further investigated their effects on lipid metabolism and blood lipid levels in obese rats. Quinoa bran dietary fiber showed significantly reduced body weight, blood glucose level, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels compared to those in the model group of obese rats. Aspartate aminotransferase and alanine aminotransferase levels were significantly lower in the IDF group, demonstrating that IDF improved liver injury more significantly than SDF, which was consistent with the analysis of liver tissue sections. IDF supplementation significantly improved the oxidation resistance of obese rats by decreasing malondialdehyde and increasing superoxide dismutase and glutathione peroxidase levels compared to the high-fat diet group levels. Transcriptome analysis showed that IDF caused hepatic changes in genes (Ehhadh, PPARα, FADS, CPT1, CPT2, SCD-1, Acadm, and CYP7A1) related to fatty acid degradation, and this result coincided with that of the gene expression validation result.

CONCLUSION

Overall, our research offers crucial data for the logical development of dietary fiber from quinoa bran with nutritional purposes. © 2023 Society of Chemical Industry.

Longitudinal Relationship between the Percentage of Energy Intake from Macronutrients and Overweight/Obesity among Chinese Adults from 1991 to 2018

To investigate the prospective relationship between macronutrient intake and overweight/obesity, data were collected in the China Health and Nutrition Survey (CHNS) from 1991 to 2018. Adults who participated in at least two waves of the survey and were not obese at baseline were selected as the study subjects. A total of 14,531 subjects were finally included with complete data. Overweight/obesity was defined as a body mass index (BMI) ≥ 24.0 kg/m2. The generalized estimating equation (GEE) was used to analyze the relationship between the percentage of energy intake from macronutrients and BMI and overweight/obesity. The percentages of energy intake from protein and fat showed an increasing trend (p < 0.01), and the percentage of energy intake from carbohydrate showed a decreasing trend (p < 0.01) among Chinese adults between 1991 and 2018. Adjusting for covariates, the energy intake from fat was positively correlated with BMI, while the energy intake from carbohydrates was negatively correlated with BMI. The percentage of energy intake from non-high-quality protein and polyunsaturated fatty acids (PUFA) were positively correlated with overweight/obesity. In contrast, monounsaturated fatty acids (MUFA) and high-quality carbohydrates were negatively correlated with overweight/obesity. In short, fat, non-high-quality protein, saturated fatty acids (SFA), and PUFA were positively correlated with the risk of obesity, whereas higher carbohydrate, MUFA, and high-quality carbohydrate intake were associated with a lower risk of obesity. Obesity can be effectively prevented by appropriately adjusting the proportion of intake from the three major macronutrients.

HIGH-FIBER DIET PROMOTES METABOLIC, HORMONAL, AND SATIETY EFFECTS IN OBESE WOMEN ON A SHORT-TERM CALORIC RESTRICTION

•Body weight and BMI decrease in both the EG and CG groups during the period of caloric restriction. •For both the EG and CG groups, fat-free mass decreases during food restriction. •Subjects on a high-fiber diet have reduced fasting glucose and basal insulin as well as improved insulin resistance, as attested by the lower HOMA-IR index. •Obese women on a high-fiber diet have suppressed postprandial (after 60 min) acylated ghrelin, confirming that the diet composition influences ghrelin levels from the first day. •In the present study, it was possible to verify that fasting leptin concentration diminishes in obese women on a high-fiber diet. Background - Several mechanisms, including excessive hunger, account for patients' difficulties in maintaining weight loss and dietary changes after caloric restriction. Objective - To evaluate the effect of short-term high-fiber calorie-restricted diet in appetite-regulating hormones, and hunger and satiety sensations in women with obesity. In a randomized controlled trial study, thirty women with body mass index (BMI) higher than 30 kg/m2, and aged from 20 to 50 years were hospitalized following a calorie-restricted diet (1000 kcal/day) for three days. The experimental group (n=15) received high-fiber diet and the control group (n=15), conventional diet. Results - Body weight, BMI, resting energy expenditure (REE), acylated and total ghrelin, leptin, insulin and glucose, and hunger and satiety sensations were evaluated. Linear regression models with mixed effects (fixed and random effects) helped to assess the variables between the two groups and within the groups. Body weight and BMI decreased in both the experimental and control groups (P<0.001). After the high-fiber diet, postprandial acylated ghrelin (P=0.04), glucose (P<0.001), insulin (P=0.04), and leptin (P=0.03) levels as well as the HOMA-IR index (P=0.01) decreased, whereas satiety improved (P=0.02). Obese women that followed the conventional diet had increased body fat percentage (P=0.04) and lower REE (P=0.02). The two diets did not differ in terms of hunger sensation. Conclusion - A short-term high-fiber diet improves satiety sensations and metabolic parameters while suppressing postprandial acylated ghrelin (60 minutes) and maintaining the resting energy expenditure.

Changes in Food and Nutrient Intake and Diet Quality on a Low-Fat Vegan Diet Are Associated with Changes in Body Weight, Body Composition, and Insulin Sensitivity in Overweight Adults: A Randomized Clinical Trial

BACKGROUND

Consuming different food groups and nutrients can have differential effects on body weight, body composition, and insulin sensitivity.

OBJECTIVE

The aim was to identify how food group, nutrient intake, and diet quality change relative to usual-diet controls after 16 weeks on a low-fat vegan diet and what associations those changes have with changes in body weight, body composition, and measures of metabolic health.

DESIGN

Secondary analysis of a randomized clinical trial conducted between October 2016 and December 2018 in four replications.

PARTICIPANTS/SETTING

Participants included in this analysis were 219 healthy, community-based adults in the Washington, DC, area, with a body mass index (BMI) between 28 and 40 kg/m², who were randomly assigned to follow either a low-fat vegan diet or make no diet changes.

INTERVENTION

A low-fat, vegan diet deriving approximately 10% of energy from fat, with weekly classes including dietary instruction, group discussion, and education on the health effects of plant-based nutrition. Control group participants continued their usual diets.

MAIN OUTCOME MEASURES

Changes in food group intake, macro- and micronutrient intake, and dietary quality as measured by Alternate Healthy Eating Index-2010 (AHEI-2010), analyzed from 3-day diet records, and associations with changes in body weight, body composition, and insulin sensitivity were assessed.

STATISTICAL ANALYSES PERFORMED

A repeated measure analysis of variance (ANOVA) model that included the factors group, subject, and time, was used to test the between-group differences throughout the 16-week study. Interaction between group and time (Gxt) was calculated for each variable. Within each diet group, paired comparison t-tests were calculated to identify significant changes from baseline to 16 weeks. Spearman correlations were calculated for the relationship between changes in food group intake, nutrient intake, AHEI-2010 score, and changes in body weight, body composition, and insulin sensitivity. The relative contribution of food groups and nutrients to weight loss was evaluated using linear regression.

RESULTS

Fruit, vegetable, legume, meat alternative, and whole grain intake significantly increased in the vegan group. Intake of meat, fish and poultry; dairy products; eggs; nuts and seeds; and added fats decreased. Decreased weight was most associated with increased intake of legumes (r=-0.38; p<.0001) and decreased intake of total meat, fish, and poultry (r=+0.43; p<.0001). Those consuming a low-fat vegan diet also increased their intake of carbohydrates, fiber, and several micronutrients and decreased fat intake. Reduced fat intake was associated with reduced body weight (r=+0.15; p=0.02) and, after adjustment for changes in BMI and energy intake, with reduced fat mass (r=+0.14; p=0.04). The intervention group's AHEI-2010 increased by 6.0 points on average in contrast to no significant change in the control group (treatment effect +7.2 [95% CI +3.7 to +10.7]; p<0.001). Increase in AHEI-2010 correlated with reduction in body weight (r=0.14; p=0.04), fat mass (r=-0.14; p=0.03), and insulin resistance as measured by HOMA-IR (r=-0.17; p=0.02), after adjustment for changes in energy intake.

CONCLUSIONS

When compared with participants' usual diets, intake of plant foods increased, and consumption of animal foods, nuts and seeds, and added fats decreased on a low-fat vegan diet. Increased legume intake was the best single food group predictor of weight loss. Diet quality as measured by AHEI-2010 improved on the low-fat vegan diet, which was associated with improvements in weight and metabolic outcomes. These data suggest that increasing low-fat plant foods and minimizing high-fat and animal foods is associated with decreased body weight and fat loss, and that a low-fat vegan diet can improve measures of diet quality and metabolic health.

Matched whole grain wheat and refined wheat milled products do not differ in glycemic response or gastric emptying in a randomized, crossover trial

BACKGROUND

Epidemiologic and some clinical studies support the view that whole grain foods have lower glycemic response than refined grain foods. However, from the perspective of food material properties, it is not clear why whole grain cereals containing mostly insoluble and nonviscous dietary fibers (e.g., wheat) would reduce postprandial glycemia.

OBJECTIVES

We hypothesized that glycemic response for whole grain wheat milled products would not differ from that of refined wheat when potentially confounding variables (wheat source, food form, particle size, viscosity) were matched. Our objective was to study the effect of whole grain wheat compared with refined wheat milled products on postprandial glycemia, gastric emptying, and subjective appetite.

METHODS

Using a randomized crossover design, healthy participants (n = 16) consumed 6 different medium-viscosity porridges made from whole grain wheat or refined wheat milled products, all from the same grain source and mill: whole wheat flour, refined wheat flour, cracked wheat, semolina, reconstituted wheat flour with fine bran, and reconstituted wheat flour with coarse bran. Postprandial glycemia, gastric emptying, and appetitive response were measured using continuous glucose monitors, the 13C-octanoic acid (8:0) breath test, and visual analog scale (VAS) ratings. Bayes factors were implemented to draw inferences about null effects.

RESULTS

Little-to-no differences were observed in glycemic responses, with lower incremental AUC between 0 and 120 min glycemic responses only for semolina [mean difference (MD): -966 mg min/dL; 95% CI: -1775, -156 mg min/dL; P = 0.02) and cracked wheat (MD: -721 mg min/dL; 95% CI: -1426, -16 mg min/dL; P = 0.04) than for whole wheat flour porridge. Bayes factors suggested weak to strong evidence for a null effect (i.e., no effect of treatment type) in glycemic response, gastric emptying, and VAS ratings.

CONCLUSIONS

Although whole grain wheat foods provide other health benefits, they did not in their natural composition confer lower postprandial glycemia or gastric emptying than their refined wheat counterparts.This trial was registered at clinicaltrials.gov as NCT03467659.

Biological Functions and Activities of Rice Bran as a Functional Ingredient: A Review

Rice bran (RB) is a nutrient-rich by-product of the rice milling process. It consists of pericarp, seed coat, nucellus, and aleurone layer. RB is a rich source of a protein, fat, dietary fibers, vitamins, minerals, and phytochemicals (mainly oryzanols and tocopherols), and is currently mostly used as animal feed. Various studies have revealed the beneficial health effects of RB, which result from its functional components including dietary fiber, rice bran protein, and gamma-oryzanol. The health effects of RB including antidiabetic, lipid-lowering, hypotensive, antioxidant, and anti-inflammatory effects, while its consumption also improves bowel function. These health benefits have drawn increasing attention to RB in food applications and as a nutraceutical product to mitigate metabolic risk factors in humans. This review therefore focuses on RB and its health benefits.

Whole- and Refined-Grain Consumption and Longitudinal Changes in Cardiometabolic Risk Factors in the Framingham Offspring Cohort

BACKGROUND

Greater whole grain (WG) consumption is associated with reduced risk of cardiovascular disease (CVD); however, few prospective studies have examined WG or refined grain (RG) intake and intermediate cardiometabolic risk factors.

OBJECTIVES

We examined the longitudinal association between WG and RG intake on changes in waist circumference (WC); fasting HDL cholesterol, triglyceride, and glucose concentrations; and blood pressure.

METHODS

Subjects were participants in the Framingham Offspring cohort study [n = 3121; mean ± SD baseline age: 54.9 ± 0.2 y; BMI (kg/m2) 27.2 ± 0.1]. FFQ, health, and lifestyle data were collected approximately every 4 y over a median 18-y follow-up. Repeated measure mixed models were used to estimate adjusted mean changes per 4-y interval in risk factors across increasing categories of WG or RG intake.

RESULTS

Greater WG intake was associated with smaller increases in WC (1.4 ± 0.2 compared with 3.0 ± 0.1 cm in the highest compared with the lowest category, respectively; P-trend < 0.001), fasting glucose concentration (0.7 ± 0.4 compared with 2.6 ± 0.2 mg/dL; P-trend < 0.001), and systolic blood pressure (SBP; 0.2 ± 0.5 compared with 1.4 ± 0.3 mm Hg; P-trend < 0.001) per 4-y interval. When stratified by sex, a stronger association with WC was observed among females than males. Higher intake of WG was associated with greater increases in HDL cholesterol and declines in triglyceride concentrations; however, these differences did not remain significant after adjustment for change in WC. Conversely, greater RG intake was associated with greater increases in WC (2.7 ± 0.2 compared with 1.8 ± 0.1 cm, P-trend < 0.001) and less decline in triglyceride concentration (-0.3 ± 1.3 compared with -7.0 ± 0.7 mg/dL, P-trend < 0.001).

CONCLUSIONS

Among middle- to older-age adults, replacing RG with WG may be an effective dietary modification to attenuate abdominal adiposity, dyslipidemia, and hyperglycemia over time, thereby reducing the risk of cardiometabolic diseases.

Impact of functional vegetable ingredients on the technical and nutritional quality of pasta

Pasta is a popular staple food around world. This makes pasta a great vehicle for delivering functional ingredients. This article reviews the popular functional ingredients - cereals, pseudocereal, legumes and vegetables, that are used to enrich pasta. The influence of these functional ingredients, additives and cooking process on pasta's nutritional, technical and sensory properties is summarized. This article focusses on the effects of different forms of these ingredients on the quality of cereal foods. Such as carrot juice pasta has a superior technical quality than carrot flour pasta. As far as can be established there are very few articles examining the effects of different forms of ingredients on pasta. Puree or liquid form raw vegetable materials offfers a better option than conventional powder form to add to semolina to produce functional pasta with superior technical quality and improved nutritional value.

Effects of psyllium seed husk powder, methylcellulose, pregelatinised starch, and cold water swelling starch on the production of gluten free crackers

Psyllium seed husk powder and pregelatinised starch crackers had comparable textural properties and sound release to wheat crackers, while the functionality of methylcellulose was limited due to low moisture addition.

Reformulation of Pastry Products to Improve Effects on Health

Obesity is increasing at an alarming rate and has been described as a global pandemic. This increase has several explanations, including an increase in caloric intake, low levels of physical activity and the nutritional composition of our diets. In addition to public health policies based on healthy dietary patterns and recommendations based on the Mediterranean and other healthy diets, food reformulation, especially of commonly consumed processed foods, such as bakery products and pastries, is needed in the fight against obesity. Among nutritional reformulation strategies, reductions in caloric density, salt, added sugar, saturated and trans-fats are important in order to reduce the associated risk of developing chronic diseases, including cardiovascular diseases, diabetes and cancer.

Obesity and adiposity: the culprit of dietary protein efficacy

Obesity and increased body adiposity have been alarmingly increasing over the past decades and have been linked to a rise in food intake. Many dietary restrictive approaches aiming at reducing weight have resulted in contradictory results. Additionally, some policies to reduce sugar or fat intake were not able to decrease the surge of obesity. This suggests that food intake is controlled by a physiological mechanism and that any behavioural change only leads to a short-term success. Several hypotheses have been postulated, and many of them have been rejected due to some limitations and exceptions. The present review aims at presenting a new theory behind the regulation of energy intake, therefore providing an eye-opening field for energy balance and a potential strategy for obesity management.

Weight loss induced by whole grain-rich diet is through a gut microbiota-independent mechanism

The prevalence of overweight and obesity has increased worldwide. Obesity is a well-known risk factor of type 2 diabetes mellitus and cardiovascular disease and raises public health concerns. Many dietary guidelines encourage the replacement of refined grains with whole grains (WGs) to enhance body weight management. Current evidence regarding interrelationships among WGs, body weight, and gut microbiota is limited and inconclusive. In this editorial, we comment on the article by Roager et al published in the recent issue of the Gut 2019; 68(1): 83-93. In the study, obese patients (25 < body mass index < 35 kg/m²) were randomly assigned to receive two 8-wk dietary controlling periods with WGs and refined grain-rich diet. The results showed significantly decreased body weight in the WG group. Either the composition of gut microbiota or short-chain fatty acids, the leading end product of fermentation of non-digestible carbohydrate by gut microbiota, did not differ between the two groups. The study highly indicated that a WG-rich diet reduced body weight independent of gut microbiota. We then raised some plausible mechanisms of how WGs might influence body weight and demonstrated more literature in line with WGs enhance body weight control through a microbiota-independent pathway. Possible mechanisms include: (1) The abundant dietary fiber contents of WGs increase satiety, satiation, energy excretion from stool, and energy expenditure simultaneously decreasing energy absorption and fat storage; (2) The plentiful amount of polyphenols of WGs improve energy expenditure by hampering adipocyte maturation and function; (3) The sufficient magnesium and zinc of WGs guarantee lean body mass growth and decrease fat mass; (4) The effect of WGs on brown adipose tissue is a key component of non-shivering thermogenesis; and (5) The increase of adiponectin by WGs enhances glucose utilization, lipid oxidation, and energy expenditure.

Prevotella Abundance Predicts Weight Loss Success in Healthy, Overweight Adults Consuming a Whole-Grain Diet Ad Libitum: A Post Hoc Analysis of a 6-Wk Randomized Controlled Trial

BACKGROUND

The key to effective weight loss may be to match diet and gut microbes, since recent studies have found that subjects with high Prevotella abundances in their gut microbiota lose more weight on diets rich in fiber than subjects with low Prevotella abundances.

OBJECTIVES

We reanalyzed a 6-wk, parallel, randomized trial to investigate difference in body weight changes when participants, stratified by fecal microbiota composition, consumed ad libitum a whole-grain (WG) or a refined-wheat (RW) diet.

METHODS

We stratified 46 (19 men, 27 women; ages 30-65 y) healthy, overweight adults by baseline Prevotella-to-Bacteroides ratios and Prevotella abundances. Subjects with no Prevotella were analyzed separately (n = 24). Compared with the RW diet (mean = 221 g/d), the WG diet (mean = 228 g/d) had a higher fiber content (33 g/d compared with 23 g/d). Linear mixed models and correlations were applied to link 6-wk changes in body weights and metabolic and microbiota markers, according to Prevotella groups and diets.

RESULTS

The Prevotella abundances correlated inversely with weight changes (r = -0.34; P = 0.043). Consequently, subjects with high Prevotella abundances (n = 15) spontaneously lost 1.80 kg (95% CI: -3.23, -0.37 kg; P = 0.013) more on the WG diet than on the RW diet, whereas those with low Prevotella abundances (n = 31) were weight stable (-0.22 kg; 95% CI: -1.40, 0.96 kg; P = 0.72). Thus, the mean difference between the Prevotella groups was 2.02 kg (95% CI: -3.87, -0.17 kg; P = 0.032). Subjects with no Prevotella lost 1.59 kg (95% CI: -2.65, -0.52 kg; P = 0.004) more on the WG diet than on the RW diet. No 6-wk changes in appetite sensations, glucose metabolisms, or fecal SCFAs were associated with the Prevotella groups.

CONCLUSIONS

Healthy, overweight adults with high Prevotella abundances lost more weight than subjects with low Prevotella abundances when consuming a diet rich in WG and fiber ad libitum for 6 wk. This further supports enterotypes as a potential biomarker in personalized nutrition for obesity management. This t rial was registered at clinicaltrials.gov as NCT02358122.

Preparation and Evaluation of Functional Foods for Prevention of Non-alcoholic Fatty Liver Disease

BACKGROUND AND OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is a public health problem presenting one of the most important common forms of liver diseases worldwide. This study was carried out to investigate the protective effect of two functional foods in form of bread containing purslane seeds meal and garden cress seeds against NAFLD.

MATERIALS AND METHODS

High fat and high cholesterol diet were used for induction of NAFLD in rats for 6 weeks. Plasma lipid profile (total cholesterol, triglycerides, high density lipoprotein-cholesterol and low-density lipoprotein-cholesterol, hepatic lipid profile (total fat, cholesterol, triglycerides), malondialdehyde (MDA), as well as liver (AST, ALT, total and direct bilirubin) and kidney (creatinine and urea) functions were assessed. Histological examination of liver tissue was carried out.

RESULTS

Results revealed that significant elevation in plasma and liver lipid profiles, MDA, liver enzymes (AST and ALT), bilirubin (total and direct) and kidney function (creatinine and urea) were observed in NAFLD control compared to normal control. Feeding rats on diet containing functional food I and II (purslane and garden cress bread, respectively) showed significant improvement in all the studied parameters with remarkable effect regards to functional food I (purslane bread).

CONCLUSION

Purslane bread and garden cress bread as functional foods prepared in the present study prevent weight gain, improve plasma lipid profile and prevent hepatic lipid accumulation effectively in NAFLD model in rats. Also decreased lipid peroxidation, improve liver and kidney functions and possess hypoglycemic effect. Purslane bread was superior in the prevention of hepatic lipid accumulation.

The Relationship between Whole Grain Intake and Body Weight: Results of Meta-Analyses of Observational Studies and Randomized Controlled Trials

Results from some observational studies suggest that higher whole grain (WG) intake is associated with lower risk of weight gain. Ovid Medline was used to conduct a literature search for observational studies and randomized controlled trials (RCTs) assessing WG food intake and weight status in adults. A meta-regression analysis of cross-sectional data from 12 observational studies (136,834 subjects) and a meta-analysis of nine RCTs (973 subjects) was conducted; six prospective cohort publications were qualitatively reviewed. Cross-sectional data meta-regression results indicate a significant, inverse correlation between WG intake and body mass index (BMI): weighted slope, −0.0141 kg/m² per g/day of WG intake (95% confidence interval (CI): −0.0207, −0.0077; r = −0.526, p = 0.0001). Prospective cohort results generally showed inverse associations between WG intake and weight change with typical follow-up periods of five to 20 years. RCT meta-analysis results show a nonsignificant pooled standardized effect size of −0.049 kg (95% CI −0.297, 0.199, p = 0.698) for mean difference in weight change (WG versus control interventions). Higher WG intake is significantly inversely associated with BMI in observational studies but not RCTs up to 16 weeks in length; RCTs with longer intervention periods are warranted.

Maternal feeding practices in relation to dietary intakes and BMI in 5 year-olds in a multi-ethnic Asian population

BACKGROUND

In Asia, little is known about how maternal feeding practices are associated with dietary intakes and body mass index (BMI) in preschoolers.

OBJECTIVE

To assess the relationships between maternal feeding practices with dietary intakes and BMI in preschoolers in Asia using cross-sectional analysis in the GUSTO (Growing Up in Singapore Towards healthy Outcomes) cohort.

PARTICIPANT SETTINGS

Mothers (n = 511) who completed the Comprehensive Feeding Practices Questionnaire (CFPQ) and a semi-quantitative Food Frequency Questionnaire (FFQ) when children were 5 years old.

STATISTICAL ANALYSIS

Associations between 12 maternal feeding practices (mean scores divided into tertiles) and children's dietary intakes of seven food groups and BMI z-scores were examined using the general linear regression model. Weight and height of the child were measured, and dietary intakes derived from the FFQ.

RESULTS

Compared to those in the low tertile, mothers in the high tertile of modelling healthy food intakes had children with higher intakes of vegetables[+20.0g/day (95%CI:11.6,29.5)] and wholegrains[+ 20.9g/day (9.67,31.1)] but lower intakes of sweet snacks[-10.1g/day (-16.3,-4.94)] and fast-foods[-5.84g/day (-10.2,-1.48)]. Conversely, children of mothers in the high tertile for allowing child control (lack of parental control) had lower intake of vegetables[-15.2g/day (-26.6,-5.21)] and wholegrains[-13.6g/day (-22.9,-5.27)], but higher intakes of sweet snacks[+13.7g/day (7.7, 19.8)] and fast-foods[+6.63g/day (3.55,9.72)]. In relation to BMI at 5 years, food restrictions for weight was associated with higher BMI z-scores [0.86SD (0.61,1.21)], while use of pressure was associated with lower BMI z-scores[-0.49SD(-0.78,-0.21)].

CONCLUSIONS AND IMPLICATIONS

Modelling healthy food intakes by mothers was the key feeding practice associated with higher intakes of healthy foods and lower intakes of discretionary foods. The converse was true for allowing child control. Only food restrictions for weight and use of pressure were associated with BMI z-scores.

Dietary Fibre as a Unifying Remedy for the Whole Spectrum of Obesity-Associated Cardiovascular Risk

Obesity is a pandemic carrying the heavy burden of multiple and serious co-morbidities including metabolic syndrome, type 2 diabetes and cardiovascular diseases. The pathophysiological processes leading to the accumulation of body fat slowly evolve to fat accumulation in other body compartments than subcutaneous tissue. This abnormal fat deposition determines insulin resistance which in turn causes blood glucose and lipid metabolism derangement, non-alcoholic fatty liver disease, hypertension, and metabolic syndrome. All these conditions contribute to increase the cardiovascular risk of obese people. Several randomized clinical trials demonstrated that moderate weight loss (5⁻10%) in obese patients improves obesity-related metabolic risk factors and coexisting disorders. Therefore, nutritional strategies able to facilitate weight management, and in the meantime positively influence obesity-associated cardiovascular risk factors, should be implemented. To this aim, a suitable option could be dietary fibres that may also act independently of weight loss. The present narrative review summarizes the current evidence about the effects of dietary fibres on weight management in obese people. Moreover, all of the different cardiovascular risk factors are individually considered and evidence on cardiovascular outcomes is summarized. We also describe the plausible mechanisms by which different dietary fibres could modulate cardio-metabolic risk factors. Overall, despite both epidemiological and intervention studies on weight loss that show statistically significant but negligible clinical effects, dietary fibres seem to have a beneficial impact on main pathophysiological pathways involved in cardiovascular risk (i.e., insulin resistance, renin-angiotensin, and sympathetic nervous systems). Although the evidence is not conclusive, this suggests that fibre would be a suitable option to counteract obesity-related cardio-metabolic diseases also independently of weight loss. However, evidence is not consistent for the different risk factors, with clear beneficial effects shown on blood glucose metabolism and Low Density Lipoprotein (LDL) cholesterol while there is fewer, and less consistent data shown on plasma triglyceride and blood pressure. Ascribing the beneficial effect of some foods (i.e., fruits and vegetables) solely to their fibre content requires more investigation on the pathophysiological role of other dietary components, such as polyphenols.

Prediction of body fat loss in relation to change in nutrient intake among housewives participating in the MyBFF@home study

BACKGROUND

Diet compositions are likely to be one of the influential factors for body fat deposition. The aim of this paper was to determine the nutrient changes and its association to body fat loss among the overweight and obese housewives in the MyBFF@home study.

METHODS

Data of participants in the MyBFF@home study (intervention and control groups) were analysed. Participants in the intervention group received personalised dietary counselling consisted of reduced calorie diet 1200-1500 kcal/day, while the control group was assigned to receive women's health seminars. The dietary assessment was done during the intervention phase at baseline, 1 month (m), 2 m, 3 m and 6 m using a 3-day food diary. Body fat was measured using a bioelectrical impedance analyser (In-body 720) at baseline and at the end of the intervention phase. The mean differences of nutrient intake and body compositions during the intervention phase were measured with paired t-test. The changes in body fat and nutrients intake were calculated by subtracting baseline measurements from those taken at 6 months. Multiple linear regression analysis was conducted to determine the extent to which the changes in each gram of nutrients per 1000 kcal were predictive of changes in body fat mass.

RESULTS

There were significant reductions in energy, all macronutrients, dietary fibre, calcium and iron intake in both study groups after the intervention phase (p <  0.05). In the intervention group, body fat loss increased with the reduction of each gram of carbohydrate, protein and fat per 1000 kcal, (p <  0.05), and decreased with the reduction of each gram of calcium and fibre intake per 1000 kcal (p <  0.05). In the control group, body fat loss increased with the reduction of each gram fat per 1000 kcal (p <  0.05) and decreased with the reduction of each gram iron per 1000 kcal.

CONCLUSION

Changes in the intake of various nutrients have different effects on body fat loss between the intervention and control group.

Association between whole grain intake and all-cause mortality: a meta-analysis of cohort studies

Some observational studies have examined the association between dietary whole grain intake and all-cause mortality, but the results were inconclusive. We therefore conducted a meta-analysis to summarize the evidence from cohort studies regarding the association between whole grain intake and all-cause mortality. Pertinent studies were identified by searching PubMed, Embase and Web of Knowledge, up to February 28, 2016. Study-specific estimates were combined using random-effects models. Eleven prospective cohort studies involving 101,282 deaths and 843,749 participants were included in this meta-analysis. The pooled relative risk of all-cause mortality for the highest category of whole grain intake versus lowest category was 0.82 (95% confidence interval: 0.78, 0.87). There was a 7% reduction in risk associated with each 1 serving/day increase in whole grain intake (relative risk = 0.93; 95% confidence interval: 0.89, 0.97). No publication bias was found. This analysis indicates that higher intake of whole grain is associated with a reduced risk of all-cause mortality. The findings support current recommendations for increasing whole grain consumption to promote health and overall longevity.

Subjective satiety and plasma PYY concentration after wholemeal pasta

Dietary fiber and whole grain foods may contribute to the regulation of appetite; however, evidence has produced inconclusive findings. The objective was to evaluate the effects of an experimental wholemeal pasta on appetite ratings, plasma concentrations of gastrointestinal hormones involved in appetite control, and postprandial glucose/insulin responses in healthy adults. Fourteen healthy adults (7M/7F), mean age 30±2 yrs (mean±SEM), participated in a randomized, controlled, crossover trial. Participants consumed on two different days, at one week interval, 117g of wholemeal pasta or 100g of refined wheat pasta (control pasta), similar in energy and macronutrient composition except for fiber amount, which was higher in wholemeal pasta (11 vs 3 g). Appetite ratings, glucose/insulin/lipid and gastrointestinal hormone responses were measured at fasting and for 4-h after the ingestion of the pasta tests, after which self-reported energy intake for 8-h was evaluated. After the wholemeal pasta, the desire to eat and the sensation of hunger were lower (-16%, p=0.04 and -23%, p=0.004, respectively) and satiety was higher (+13%; p=0.08) compared with the control pasta; no effect on self-reported energy intake at subsequent meal was observed. After wholemeal pasta, glucose, triglyceride increased and GLP-1 responses were not different compared to control pasta but insulin response at 30 min (p<0.05) and ghrelin at 60 min (p=0.03) were lower and PYY levels higher (AUC=+44%, p=0.001). The appetite rating changes correlated with PYY plasma levels (p<0.03). In conclusion, consumption of whole grain instead of refined wheat pasta contributed to appetite control but did not seem to influence acute energy balance. Appetite ratings were associated with modifications in PYY hormone concentrations.

Association of Dietary Patterns with Components of Metabolic Syndrome and Inflammation among Middle-Aged and Older Adults with Metabolic Syndrome in Taiwan

This study examined the correlation of dietary patterns with components of metabolic syndrome (MetS) and inflammation among middle-aged and older adults with MetS in Taiwan. This cross-sectional study used data from the Mei Jau International Health Management Institution in Taiwan between 2004 and 2013. A total of 26,016 subjects aged 35 years and above were selected for analysis. MetS was defined according to the International Diabetes Federation. Three dietary patterns were identified by principal component analysis. High intake of a meat–instant food dietary pattern (rich in animal protein, saturated fat, sweets, sodium, and food additives) was positively associated with components of MetS and C-reactive protein (CRP), while high intake of a vege–seafood dietary pattern (rich in dietary fiber, vitamins, minerals, and unsaturated fat) or a cereal–dairy dietary pattern (rich in dietary fiber, antioxidants, phytochemicals, complex carbohydrate, prebiotics, and probiotics) was inversely associated with components of MetS and CRP. Our findings suggested that intake of a vege–seafood dietary pattern or a cereal–dairy dietary pattern decreased the risk of developing MetS and inflammation among middle-aged and older adults with MetS.

National pattern of grain products consumption among Canadians in association with body weight status

Background

Obesity in Canadian adults is showing upward trends. Consumption of whole-grains is one recommendation for the prevention of obesity. Despite the apparent nutritional and energy content differences between whole and refined grains, knowledge relating refined grains to weight gain in Canadian adults is scarce. The aim of this study was to assess the consumption of specific grain-based foods at the regional and national levels, and to evaluate the association between grain consumption with overweight or obesity in Canadian adults.

Methods

We used the 2004 Canadian Community Health Survey data. The association between type of grain product consumed and Body Mass Index (BMI) in adults aged ≥19y was evaluated by logistic regression.

Results

The mean daily intake of whole grains (86 ± 1.9 g/day) was significantly less than refined grains (276.6 ± 3.8 g/day), which was different across provinces. After adjustment for caloric needs, male consumers showed significantly lower intake of whole grains than females. Accordingly, the incidence of overweight or obesity was higher in males than in females. Also, in comparison to whole grains, the consumption of refined grains was associated with a higher risk of overweight or obesity among adults.

Conclusion

Canadians’ preference was refined grain products consumption, based on 2004 Health Survey, which was significantly associated with overweight/obesity. Hence, consumption of whole grains should be more effectively promoted rather than refined grain products to prevent obesity and its complications such as cardiovascular diseases and type 2 diabetes.

Electronic supplementary material

The online version of this article (doi:10.1186/s40795-017-0183-x) contains supplementary material, which is available to authorized users.

Effect of Whole Grain Qingke (Tibetan Hordeum vulgare L. Zangqing 320) on the Serum Lipid Levels and Intestinal Microbiota of Rats under High-Fat Diet

This study investigated the hypolipidemic effect of whole grain Qingke (WGQ) and its influence on intestinal microbiota. Changes in the serum lipid, intestinal environment, and microbiota of Sprague-Dawley rats fed high-fat diets supplemented with different doses of WGQ were determined. Results showed that high doses of WGQ significantly decreased (P < 0.05) the Lee's index, serum total cholesterol, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol levels whereas they increased the body weight of the rats. Cecal weight and short-chain fatty acid (SCFA) concentration increased with increasing WGQ dose. An Illumina-based sequencing approach showed that the relative abundance of putative SCFA-producing bacteria Prevotella and Anaerovibrio increased in the rats fed the WGQ diet. Principal component analysis revealed a significant difference in intestinal microbiota composition after the administration of the WGQ diet. These findings provide insights into the contribution of the intestinal microbiota to the hypolipidemic effect of WGQ.

Substituting whole grains for refined grains in a 6-wk randomized trial favorably affects energy-balance metrics in healthy men and postmenopausal women

Background: The effect of whole grains on the regulation of energy balance remains controversial.Objective: We aimed to determine the effects of substituting whole grains for refined grains, independent of body weight changes, on energy-metabolism metrics and glycemic control.Design: The study was a randomized, controlled, parallel-arm controlled-feeding trial that was conducted in 81 men and postmenopausal women [49 men and 32 women; age range: 40-65 y; body mass index (in kg/m²): <35.0]. After a 2-wk run-in period, participants were randomly assigned to consume 1 of 2 weight-maintenance diets for 6 wk. Diets differed in whole-grain and fiber contents [mean ± SDs: whole grain-rich diet: 207 ± 39 g whole grains plus 40 ± 5 g dietary fiber/d; refined grain-based diet: 0 g whole grains plus 21 ± 3 g dietary fiber/d] but were otherwise similar. Energy metabolism and body-composition metrics, appetite, markers of glycemic control, and gut microbiota were measured at 2 and 8 wk.Results: By design, body weight was maintained in both groups. Plasma alkylresorcinols, which are biomarkers of whole-grain intake, increased in the whole grain-rich diet group (WG) but not in the refined grain-based diet group (RG) (P-diet-by-time interaction < 0.0001). Beta ± SE changes (ΔWG compared with ΔRG) in the resting metabolic rate (RMR) (43 ± 25 kcal/d; P = 0.04), stool weight (76 ± 12 g/d; P < 0.0001), and stool energy content (57 ± 17 kcal/d; P = 0.003), but not in stool energy density, were higher in the WG. When combined, the favorable energetic effects in the WG translated into a 92-kcal/d (95% CI: 28, 156-kcal/d) higher net daily energy loss compared with that of the RG (P = 0.005). Prospective consumption (P = 0.07) and glycemia after an oral-glucose-tolerance test (P = 0.10) trended toward being lower in the WG than in the RG. When nonadherent participants were excluded, between-group differences in stool energy content and glucose tolerance increased, and between-group differences in the RMR and prospective consumption were not statistically significant.Conclusion: These findings suggest positive effects of whole grains on the RMR and stool energy excretion that favorably influence energy balance and may help explain epidemiologic associations between whole-grain consumption and reduced body weight and adiposity. This trial was registered at clinicaltrials.gov as NCT01902394.

High wholegrain barley β-glucan lowers food intake but does not alter small intestinal macronutrient digestibility in ileorectostomised rats

Using barley cultivars differing widely in β-glucan content, we aimed to determine their effects on small intestinal macronutrient digestion in 24 ileorectostomised rats. The rats were fed 1 of 4 experimental diets, each containing a different barley variety, for 11 d. The diets had a content of 0, 2.1, 2.6 and 4.3 g of β-glucan/100 g. Feed intake and faecal excretion of fat, protein, starch, and non-starch polysaccharides were determined in the final 5 d of the study and apparent macronutrient digestibility calculated. Higher dietary levels of β-glucan (2.6% and 4.3%) lowered feed intake (by 15 and 19%, respectively) but final body weight was only lowered by the 4.3% β-glucan diet relative to rats fed the 0% β-glucan diet (all ps < 0.05). Protein, lipid and starch digestibility was unrelated to the dietary β-glucan content. Higher dietary levels of barley β-glucan lower feed intake of ileorectostomised rats, which is independent of intestinal fermentation and unrelated to macronutrient digestibility.

Impact of brisk walking and aerobics in overweight women

[Purpose] Lack of physical activity and an uncontrolled diet cause excessive weight gain, which leads to obesity and other metabolic disorders. Studies have indicated that brisk walking and aerobics are the best methods for controlling and reducing weight and body mass composition. [Subjects and Methods] In this study, 45 overweight women were enrolled and divided into 3 groups. Women not involved in brisk walking or aerobics were included in group A (n = 15) as control subjects; women involved in brisk walking were in group B (n = 15); and those involved in aerobics were in group C (n = 15). [Results] This program was carried out 5 days/week for 10 weeks. Pre- and post-measurements of body mass index, waist and hip circumference, and skinfold thickness of the abdomen, subscapular area, biceps, and triceps were recorded for the women in all 3 groups. All values decreased in women who participated in brisk walking and aerobics for 10 weeks. [Conclusion] These results indicate that aerobics with diet therapy is a more effective intervention program for controlling and reducing body mass index and skinfold thickness than brisk walking with diet therapy in North Indian women.

Whole-grain products and whole-grain types are associated with lower all-cause and cause-specific mortality in the Scandinavian HELGA cohort

No study has yet investigated the intake of different types of whole grain (WG) in relation to all-cause and cause-specific mortality in a healthy population. The aim of the present study was to investigate the intake of WG products and WG types in relation to all-cause and cause-specific mortality in a large Scandinavian HELGA cohort that, in 1992–8, included 120 010 cohort members aged 30–64 years from the Norwegian Women and Cancer Study, the Northern Sweden Health and Disease Study, and the Danish Diet Cancer and Health Study. Participants filled in a FFQ from which data on the intake of WG products were extracted. The estimation of daily intake of WG cereal types was based on country-specific products and recipes. Mortality rate ratios (MRR) and 95 % CI were estimated using the Cox proportional hazards model. A total of 3658 women and 4181 men died during the follow-up (end of follow-up was 15 April 2008 in the Danish sub-cohort, 15 December 2009 in the Norwegian sub-cohort and 15 February 2009 in the Swedish sub-cohort). In the analyses of continuous WG variables, we found lower all-cause mortality with higher intake of total WG products (women: MRR 0·89 (95 % CI 0·86, 0·91); men: MRR 0·89 (95 % CI 0·86, 0·91) for a doubling of intake). In particular, intake of breakfast cereals and non-white bread was associated with lower mortality. We also found lower all-cause mortality with total intake of different WG types (women: MRR 0·88 (95 % CI 0·86, 0·92); men: MRR 0·88 (95 % CI 0·86, 0·91) for a doubling of intake). In particular, WG oat, rye and wheat were associated with lower mortality. The associations were found in both women and men and for different causes of deaths. In the analyses of quartiles of WG intake in relation to all-cause mortality, we found lower mortality in the highest quartile compared with the lowest for breakfast cereals, non-white bread, total WG products, oat, rye (only men), wheat and total WG types. The MRR for highest v. lowest quartile of intake of total WG products was 0·68 (95 % CI 0·62, 0·75, Ptrend over quartiles< 0·0001) for women and 0·75 (95 % CI 0·68, 0·81, Ptrend over quartiles< 0·0001) for men. The MRR for highest v. lowest quartile of intake of total WG types was 0·74 (95 % CI 0·67, 0·81, Ptrend over quartiles< 0·0001) for women and 0·75 (95 % CI 0·68, 0·82, Ptrend over quartiles< 0·0001) for men. Despite lower statistical power, the analyses of cause-specific mortality according to quartiles of WG intake supported these results. In conclusion, higher intake of WG products and WG types was associated with lower mortality among participants in the HELGA cohort. The study indicates that intake of WG is an important aspect of diet in preventing early death in Scandinavia.

Can whole grain help in weight management?

BACKGROUND

Evidence from epidemiological studies suggests that higher whole grain intake is associated with improvements in body weight measures. Evidence from randomized controlled intervention studies is controversial.

OBJECTIVE

To assess the scientific evidence, using a descriptive systematic approach, related to the relationship/effects of whole grain on weight management.

METHODS

Medicine Medical Subject Headings (MeSH) were used to search in Medline and Scopus, dating from 1980 to July 2013. Subsequently, 2 researchers assessed independently the resulting abstracts, using hierarchically targeted selection criteria.

RESULTS

A moderate body of evidence from epidemiological studies consistently demonstrates that a higher intake of whole grains is associated with lower body weight, BMI, waist circumference, abdominal adiposity, and weight gain. The evidence from intervention studies is, in comparison, limited and less consistent. Current evidence fails to clearly demonstrate that whole grain intake can contribute to weight loss independent of hypocaloric diets. The lack of consistency in intervention studies may partly be explained by heterogeneity in study duration, types and amounts of whole grain foods included, population, and sample sizes.

CONCLUSIONS

Future epidemiological and intervention studies are needed to address the limitations observed in the current body of evidence, importantly using a consistent definition of whole grain foods, and the amount of whole grains consumed. Furthermore, studies need to be conducted on diets that potentially include single grains.

Association between Mediterranean and Nordic diet scores and changes in weight and waist circumference: influence of FTO and TCF7L2 loci

BACKGROUND

Several studies have shown that adherence to the Mediterranean Diet measured by using the Mediterranean diet score (MDS) is associated with lower obesity risk. The newly proposed Nordic Diet could hold similar beneficial effects. Because of the increasing focus on the interaction between diet and genetic predisposition to adiposity, studies should consider both diet and genetics.

OBJECTIVE

We investigated whether FTO rs9939609 and TCF7L2 rs7903146 modified the association between the MDS and Nordic diet score (NDS) and changes in weight (Δweight), waist circumference (ΔWC), and waist circumference adjusted for body mass index (BMI) (ΔWCBMI).

DESIGN

We conducted a case-cohort study with a median follow-up of 6.8 y that included 11,048 participants from 5 European countries; 5552 of these subjects were cases defined as individuals with the greatest degree of unexplained weight gain during follow-up. A randomly selected subcohort included 6548 participants, including 5496 noncases. Cases and noncases were compared in analyses by using logistic regression. Continuous traits (ie, Δweight, ΔWC, and ΔWCBMI) were analyzed by using linear regression models in the random subcohort. Interactions were tested by including interaction terms in models.

RESULTS

A higher MDS was significantly inversely associated with case status (OR: 0.98; 95% CI: 0.96, 1.00), ΔWC (β = -0.010 cm/y; 95% CI: -0.020, -0.001 cm/y), and ΔWCBMI (β = -0.008; 95% CI:-0.015, -0.001) per 1-point increment but not Δweight (P = 0.53). The NDS was not significantly associated with any outcome. There was a borderline significant interaction between the MDS and TCF7L2 rs7903146 on weight gain (P = 0.05), which suggested a beneficial effect of the MDS only in subjects who carried 1 or 2 risk alleles. FTO did not modify observed associations.

CONCLUSIONS

A high MDS is associated with a lower ΔWC and ΔWCBMI, regardless of FTO and TCF7L2 risk alleles. For Δweight, findings were less clear, but the effect may depend on the TCF7L2 rs7903146 variant. The NDS was not associated with anthropometric changes during follow-up.

Gene-diet interaction and weight loss

PURPOSE OF REVIEW

The purpose of this review is to summarize recent advances in investigations of dietary factors, genetic factors, and their interactive effects on obesity and weight loss.

RECENT FINDINGS

Even with a tremendous body of research conducted, controversy still abounds regarding the relative effectiveness of various weight-loss diets. Recent advances in genome-wide association studies have made great strides in unraveling the genetic basis of regulation of body weight. In prospective cohorts, reproducible evidence is emerging to show interactions between genetic factors and dietary factors such as sugar-sweetened beverage on obesity. In randomized clinical trials, individuals' genotypes have also been found to modify diet interventions on weight loss, weight maintenance, and changes in related metabolic traits such as lipids, insulin resistance, and blood pressure. However, replication, functional exploration, and translation of the findings into personalized diet interventions remain the chief challenges.

SUMMARY

Preliminary but promising data have emerged to lend support to gene-diet interaction in determining weight loss and maintenance; and studies in the area hold great promise to inform future personalized diet interventions on the reduction of obesity and related health problems.