Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes

Effects of whole grains on glycemic control: a systematic review and dose-response meta-analysis of prospective cohort studies and randomized controlled trials

PURPOSE

Whole grains have recently been promoted as beneficial to diabetes prevention. However, the evidence for the glycemic benefits of whole grains seems to conflict between the cohort studies and randomized control trials (RCTs). To fill the research gap, we conducted a meta-analysis to determine the effects of whole grains on diabetes prevention and to inform recommendations.

METHODS

We searched PubMed, Clarivate Web of Science, and Cochrane Library until March 2024. We used the risk ratio (RR) of type 2 diabetes to represent the clinical outcomes for cohort studies, while the biomarkers, including fasting blood glucose and insulin, HbA1C, and HOMA-IR, were utilized to show outcomes for RCTs. Dose-response relationships between whole grain intakes and outcomes were tested with random effects meta-regression models and restricted cubic splines models. This study is registered with PROSPERO, CRD42021281639.

RESULTS

Ten prospective cohort studies and 37 RCTs were included. Cohort studies suggested a 50 g/day whole grain intake reduced the risk of type 2 diabetes (RR = 0.761, 95% CI: 0.700 to 0.828, I2 = 72.39%, P < 0.001) and indicated a monotonic inverse relationship between whole grains and type 2 diabetes rate. In RCTs, whole grains significantly reduced fasting blood glucose (Mean difference (MD) = -0.103 mmol/L, 95% CI: -0.178 to -0.028; I2 = 72.99%, P < 0.01) and had modest effects on HbA1C (MD = -0.662 mmol/mol (-0.06%), 95% CI: -1.335 to 0.010; I2 = 64.55%, P = 0.05) and HOMA-IR (MD = -0.164, 95% CI: -0.342 to 0.013; I2 = 33.38%, P = 0.07). The intake of whole grains and FBG, HbA1C, and HOMA-IR were significantly dose-dependent. The restricted spline curves remained flat up to 150 g/day and decreased afterward. Subgroup analysis showed that interventions with multiple whole-grain types were more effective than those with a single type.

CONCLUSION

Our study findings suggest that a daily intake of more than 150 g of whole grain ingredients is recommended as a population approach for diabetes prevention.

Serum metabolites associated with wholegrain consumption using nontargeted metabolic profiling: a discovery and reproducibility study

PURPOSE

To identify fasting serum metabolites associated with WG intake in a free-living population adjusted for potential confounders.

METHODS

We selected fasting serum samples at baseline from a subset (n = 364) of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) cohort. The samples were analyzed using nontargeted metabolomics with liquid chromatography coupled with mass spectrometry (LC-MS). Association with WG intake was investigated using both random forest followed by linear regression adjusted for age, BMI, smoking, physical activity, energy and alcohol consumption, and partial Spearman correlation adjusted for the same covariates. Features selected by any of these models were shortlisted for annotation. We then checked if we could replicate the findings in an independent subset from the same cohort (n = 200).

RESULTS

Direct associations were observed between WG intake and pipecolic acid betaine, tetradecanedioic acid, four glucuronidated alkylresorcinols (ARs), and an unknown metabolite both in discovery and replication cohorts. The associations remained significant (FDR<0.05) even after adjustment for the confounders in both cohorts. Sinapyl alcohol was positively correlated with WG intake in both cohorts after adjustment for the confounders but not in linear models in the replication cohort. Some microbial metabolites, such as indolepropionic acid, were positively correlated with WG intake in the discovery cohort, but the correlations were not replicated in the replication cohort.

CONCLUSIONS

The identified associations between WG intake and the seven metabolites after adjusting for confounders in both discovery and replication cohorts suggest the potential of these metabolites as robust biomarkers of WG consumption.

Effects of whole grain intake on glycemic control: a meta-analysis of randomized controlled trials

Aims/Introduction

Although mounting evidence has suggested an inverse association between the intake of whole grains and glycemic control, findings from randomized controlled trials are still conflicting. The current study was carried out to evaluate the effect of medium/long‐term whole grain intake on glycemic control in metabolic syndrome and healthy populations.

Materials and Methods

A literature search was carried out to identify qualified studies up to July 2021. The effects of whole grain consumption on glycemic control were calculated using a fixed effects model. Subgroup analysis was used to study whether grouping factors were important influencing factors of heterogeneity between research results.

Results

A total of 32 randomized controlled trials with 2,060 participants were included in the analyses. Whole grain consumption showed a significant inverse regulatory effect on fasting glucose concentration, but no significant effect was found for other glycemic measures, such as fasting insulin, homeostatic model assessment for insulin resistance, glycated hemoglobin and 2‐h glucose, in the pooled analysis. Through subgroup analyses, a significant decrease in fasting glucose concentration was observed for studies with a higher whole grain dose, with participants of normal glycemia, and with mixed types of whole grain.

Conclusions

Medium‐/long‐term whole grain intake reduced the fasting glucose concentration compared with similar refined foods. Appropriate intervention dose and accurate population selection might be the key links for whole grain consumption to exert its glycemic control effect.

Thirty‐two RCTs with 2060 participants were included in analyses. The whole grain consumption showed significant inverse regulation effect on fasting glucose concentration.

A diet rich in fruit and whole grains is associated with a low risk of type 2 diabetes mellitus: findings from a case-control study in South China

OBJECTIVE

Various foods are associated with or protect against type 2 diabetes mellitus (T2DM). This study was to examine the associations of foods and food patterns with the risk of T2DM in South China.

DESIGN

Case-control study.

SETTING

The dietary patterns were identified by a principal components factor analysis. Univariable and multivariable conditional logistic regression analyses were used to analyse the associations between food groups and dietary patterns and the risk of T2DM.

PARTICIPANTS

A total of 384 patients with T2DM and 768 controls.

RESULTS

After adjustment for total energy intake, the standard intake of grains (228·3 ± 71·9 v. 238·8 ± 73·1 g/d, P = 0·025) and fruits (109 ± 90 v. 145 ± 108 g/d, P < 0·001) were lower in T2DM than in controls. Four dietary patterns were identified: (1) high light-coloured vegetables and low grains, (2) high fruits, (3) high red meat and low grains and (4) high dark-coloured vegetable. After adjustment for covariables, multivariable conditional logistic regression analyses showed significant dose-dependent inverse associations between total fruit intake, whole grains intake and the score of the high-fruit dietary pattern (all Pfor trend < 0·001) and the risk of T2DM. The adjusted OR (95 % CI) for T2DM comparing the extreme quartiles were 0·46 (0·29, 0·76) for total fruits, 0·48(0·31, 0·77) for whole grains and 0·42 (0·26, 0·68) for the high-fruit dietary pattern, respectively. Similar associations were observed for all subgroups of fruits (dark-colour and light-colour).

CONCLUSION

In South China, a diet rich in fruit and whole grains is associated with lower risk of T2DM.

Design issues in personalized nutrition advice systems (Preprint)

The current health status of the general public can substantially benefit from a healthy diet. Using a personalized approach to initiate healthy dietary behavior seems to be a promising strategy, as individuals differ in terms of health status, subsequent dietary needs, and their desired behavior change support. However, providing personalized advice to a wide audience over a long period is very labor-intensive. This bottleneck can possibly be overcome by digitalizing the process of creating and providing personalized advice. An increasing number of personalized advice systems for different purposes is becoming available in the market, ranging from systems providing advice about just a single parameter to very complex systems that include many variables characterizing each individual situation. Scientific background is often lacking in these systems. In designing a personalized nutrition advice system, many design questions need to be answered, ranging from the required input parameters and accurate measurement methods (sense), type of modeling techniques to be used (reason), and modality in which the personalized advice is provided (act). We have addressed these topics in this viewpoint paper, and we have demonstrated the feasibility of setting up an infrastructure for providing personalized dietary advice based on the experience of 2 practical applications in a real-life setting.

Type 2 Diabetes-Related Health Economic Impact Associated with Increased Whole Grains Consumption among Adults in Finland

The prevalence of type 2 diabetes (T2D) is increasing rapidly worldwide. A healthy diet supporting the control of energy intake and body weight has major importance in the prevention of T2D. For example, a high intake of whole grain foods (WGF) has been shown to be inversely associated with risk for T2D. The objective of the study was to estimate the expected health economic impacts of increased WGF consumption to decrease the incidence of T2D in the Finnish adult population. A health economic model utilizing data from multiple national databases and published scientific literature was constructed to estimate these population-level health economic consequences. Among the adult Finnish population, increased WGF consumption could reduce T2D-related costs between 286€ and 989€ million during the next 10-year time horizon depending on the applied scenario (i.e., a 10%-unit increase in a proportion of daily WGF users, an increased number (i.e., two or more) of WGF servings a day, or alternatively a combination of these scenarios). Over the next 20–30 years, a population-wide increase in WGF consumption could lead to much higher benefits. Furthermore, depending on the applied scenario, between 1323 and 154,094 quality-adjusted life years (QALYs) could be gained at the population level due to decreased T2D-related morbidity and mortality during the next 10 to 30 years. The results indicate that even when the current level of daily WGF consumption is already at a relatively high-level in a global context, increased WGF consumption could lead to important health gains and savings in the Finnish adult population.

Comparing texture and digestion properties between white and brown rice of indica cultivars preferred by Chinese consumers

The consumption of good tasting rice, mainly soft-textured white rice with low amylose content, has substantially increased in China as living standards improve. However, this diet change may increase the risk of developing type II diabetes because the soft-textured white rice is generally less resistant to digestion and has a higher glycemic index. In contrast, intake of brown rice is inversely associated with type II diabetes risk. This study was conducted to test the possibility that brown rice processed from soft-textured cultivars has both acceptable texture and improved health benefits. Texture and digestion properties were compared between white and brown rice of five indica cultivars preferred by Chinese consumers. Mean hardness was 33% higher while mean springiness was 5% lower for cooked brown rice than for cooked white rice. As compared to cooked white rice, cooked brown rice had a 41% longer mean active digestion duration but 31% lower mean glucose production rate and 11% lower mean total glucose production from starch digestion. However, the differences in texture and starch digestion properties between cooked brown and white rice were affected by cultivar identity. Brown rice processed from suitable cultivars with both a relatively thinner bran layer and relatively higher grain amylose content met consumer requirements in terms of acceptable texture and improved health benefits.

Yield and quality of brown rice noodles processed from early-season rice grains

Producing rice noodles using early-season rice grains is a way to bypass difficulties in marketing early-season rice that does not meet consumer preference for soft-textured rice. In recent years, brown rice foods including noodles have attracted great attention due to their health and nutritional benefits. This study was conducted to evaluate the yield and quality of brown rice noodles processed from two early-season rice cultivars. Results showed that the yield of brown rice noodles was 12–19% higher than that of white rice noodles. Although the cooked break rate and cooking loss rate were 5–10% higher in brown rice noodles compared to white rice noodles, both were within an acceptable range for brown rice noodles. Cooked brown rice noodles had 21–27% lower hardness and chewiness than cooked white rice noodles, though differences in the elasticity parameters springiness, cohesiveness, and resilience were not significant or were inconsistent between cooked brown and white rice noodles. These results suggest that it is feasible to process early-season rice to produce brown rice noodles of desirable yield and quality.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Comprehensive Two-Dimensional Gas Chromatography-Mass Spectrometry Analysis of Exhaled Breath Compounds after Whole Grain Diets

Exhaled breath is a potential noninvasive matrix to give new information about metabolic effects of diets. In this pilot study, non-targeted analysis of exhaled breath volatile organic compounds (VOCs) was made by comprehensive two-dimensional gas chromatography-mass spectrometry (GCxGC-MS) to explore compounds relating to whole grain (WG) diets. Nine healthy subjects participated in the dietary intervention with parallel crossover design, consisting of two high-fiber diets containing whole grain rye bread (WGR) or whole grain wheat bread (WGW) and 1-week control diets with refined wheat bread (WW) before both diet periods. Large interindividual differences were detected in the VOC composition. About 260 VOCs were detected from exhaled breath samples, in which 40 of the compounds were present in more than half of the samples. Various derivatives of benzoic acid and phenolic compounds, as well as some furanones existed in exhaled breath samples only after the WG diets, making them interesting compounds to study further.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity; and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis (SEA, for its initials in Spanish), the Spanish Diabetes Society (SED, for its initials in Spanish), and the Spanish Society of Internal Medicine (SEMI, for its initials in Spanish).

Deep Dive Into the Effects of Food Processing on Limiting Starch Digestibility and Lowering the Glycemic Response

During processing of cereal-based food products, starch undergoes dramatic changes. The objective of this work was to evaluate the impact of food processing on the starch digestibility profile of cereal-based foods using advanced imaging techniques, and to determine the effect of preserving starch in its native, slowly digestible form on its in vivo metabolic fate. Four different food products using different processing technologies were evaluated: extruded products, rusks, soft-baked cakes, and rotary-molded biscuits. Imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) were used to investigate changes in slowly digestible starch (SDS) structure that occurred during these different food processing technologies. For in vivo evaluation, International Standards for glycemic index (GI) methodology were applied on 12 healthy subjects. Rotary molding preserved starch in its intact form and resulted in the highest SDS content (28 g/100 g) and a significantly lower glycemic and insulinemic response, while the three other technologies resulted in SDS contents below 3 g/100 g. These low SDS values were due to greater disruption of the starch structure, which translated to a shift from a crystalline structure to an amorphous one. Modulation of postprandial glycemia, through starch digestibility modulation, is a meaningful target for the prevention of metabolic diseases.

Diet quality, weight loss, and diabetes incidence in the Diabetes Prevention Program (DPP)

BACKGROUND

We evaluated whether diet quality is a predictor of weight loss and reduced diabetes risk, independent of caloric intake in the Diabetes Prevention Program (DPP) cohort, a randomized clinical trial of adults at risk for diabetes.

METHODS

This secondary analysis included 2914 participants with available data (964 intensive lifestyle (ILS), 977 metformin, 973 placebo). Dietary intake was assessed using a 117-item food frequency questionnaire. Diet quality was quantified using the Alternative Healthy Eating Index 2010 (AHEI). AHEI ranges from 0 to 110, with higher scores corresponding to higher quality diets. ILS participants had greater improvement (p < 0.001) in AHEI over 1-year (4.2 ± 9.0) compared to metformin (1.2 ± 8.5) and placebo (1.4 ± 8.4). We examined the association between AHEI change and weight change from baseline to 1-year using linear regression, and that between 1-year AHEI change and incident diabetes, using hazard models over an average 3 years follow-up. Models were evaluated within treatment group and adjusted for relevant characteristics including caloric intake, physical activity, BMI and AHEI. Models testing incident diabetes were further adjusted for baseline fasting and 2 h glucose.

RESULTS

An increase in AHEI score was associated with weight loss in ILS [β per 10-point increase (SE) -1.2 kg (0.3, p < 0.001)], metformin [- 0. 90 kg (0.2, p < 0.001)] and placebo [- 0.55 kg (0.2, p = 0.01)]. However, AHEI change was not associated with incident diabetes in any group before or after adjustment for weight change.

CONCLUSIONS

Controlling for weight, diet quality was not associated with diabetes incidence but helps achieve weight loss, an important factor in diabetes prevention.

Can pseudocereals modulate microbiota by functioning as probiotics or prebiotics?

Amaranth, quinoa, and buckwheat, known as pseudocereals, have been consumed since ancient times and are considered sacred in most cultures. Their grains can be used as cereals for breakfast or mixed with other grains in meals and their health-enhancing effects have been investigated more in recent years. They have an antioxidant effect and their nutrient profiles are enriched with processing techniques such as sprouting and fermentation. Their suitability to different processing techniques and the rapid increase in microbiota researches highlighted the probiotic/prebiotic effects of pseudocereals. Using cultures or naturally fermented amaranth, quinoa and buckwheat exhibited good substrate properties for probiotic bacteria, especially for Lactobacillus strains. Studies have found that they reduce the number of pathogen microorganisms, increase the synthesis of short-chain fatty acids due to their prebiotic effects. Also the number of bacterial colonies do not change during the storage period and their organoleptic properties are revealed. It has been determined that pseudocereals decrease Ruminococcacea, Lachnospiraceae, Helicobacteracea, Clostridium, Escherichia and increase Peptoclostridium, Prevotellaceae, Lactobacillus, Bifidobacterium, Enterococcus, and Eubacteriaceae. Due to these effects, they are considered as good sources for synbiotic formulations to be developed for the treatment of dysbiosis, obesity, Celiac Disease, lactose intolerance, inflammatory bowel diseases and inflammation-mediated chronic disorders.

Whole Grain Intake and Impaired Fasting Glucose in Adolescents, National Health and Nutrition Examination Survey, 2005-2014

INTRODUCTION

Large prospective cohort studies show a lower risk of developing type 2 diabetes among adults with higher whole grain consumption. Less is known about the relationship between whole grain consumption and precursors for diabetes risk in adolescents. We examined whether intake of whole grains was associated with impaired fasting glucose (IFG) in adolescents.

METHODS

We analyzed data on dietary intake from an average of two 24-hour diet recalls from fasting, nondiabetic adolescents aged 12-18 years (N = 2,286) across 5 cycles of the National Health and Nutrition Examination Survey (NHANES 2005-2014). We used logistic regression to calculate the odds of having IFG (100-125 mg/dL) with respect to servings of whole and refined grains, as well as percentage of whole grains, adjusting for sex, age, race/ethnicity, annual household income, obesity, total energy, and diet quality.

RESULTS

IFG was present in 17% of participants. After adjusting for covariates, number of servings per day of whole grains was significantly associated with lower odds of IFG, but there was no relationship between IFG and servings of refined grains or percentage of whole grains. Consuming at least 1 ounce-equivalent serving (16 g) of whole grains daily, compared with consuming no whole grains, was associated with a 40% reduction in the adjusted odds of having IFG (adjusted odds ratio = 0.60; 95% CI, 0.38-0.93).

CONCLUSION

Analysis of 10 years of national cross-sectional data suggests that US adolescents whose daily diets consist of a minimum threshold amount of whole grains may be less likely to have IFG, a finding that has implications for diabetes prevention in adolescents.

The Two Faces of Wheat

Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet.

Main Factors Influencing Whole Grain Consumption in Children and Adults-A Narrative Review

Despite their recognized health benefits, intakes of whole grains (WG) are below recommended levels in almost all countries worldwide. This observation highlights the need to increase WG consumption by understanding factors influencing this consumption and how they could be favorably impacted. This review focused on facilitators of and barriers to WG consumption and how to improve the effectiveness of programs aiming at increasing WG consumption. The main methods to facilitate WG intakes in both adults and children seem to be to (i) increase the availability and the variety of foods containing WG, (ii) improve their sensory appeal, (iii) reduce their purchase cost, (iv) use a familiarization period to introduce them to consumers (with a gradual increase in consumed amounts and repeated exposure), and (v) improve communication and labeling to enhance consumers’ ability to identify products with WG. These strategies may be used to improve the effectiveness of programs aiming at promoting WG consumption, with a further emphasis on the need to apply them over a long period of time, and potentially to include tasting sessions of new foods containing WG. Finally, these strategies should involve broad partnerships between multiple stakeholders at the regulatory, institutional and industrial levels.

Perspective: Whole and Refined Grains and Health-Evidence Supporting "Make Half Your Grains Whole"

Research-based dietary guidelines suggest that consumers "make half their grains whole." Yet some advocate ingesting only whole-grain foods (WGFs) and avoiding all refined-grain foods (RGFs). Some even recommend avoiding all grain-based foods (GBFs). This article will provide arguments to counter negative deductions about GBFs and RGFs, especially staple ones, and to support dietary guidance recommending a balance of GBFs-achieved through the right mix, type, and quantity of WGFs and RGFs. Studies looking at early mortality, body weight, and glucose tolerance and diabetes will be used as examples to characterize the literature about GBFs. The following issues are highlighted: 1) inconsistent findings between epidemiological and interventional studies and impacts of GBFs on health outcomes, and the underreporting of findings showing RGFs neither raise nor lower health risks; 2) multiple confounding and potential interactions make adequate statistical adjustment difficult; 3) nonuniform WGF definitions among studies make comparison of results challenging, especially because some WGFs may contain 49-74% refined grain (RG); 4) binary categorization of GBFs creates bias because nearly all categories of WGFs are recommended, but nearly half the RGF categories are not; 5) ingestion of >5 (30-g) servings RGFs/d and <1 serving WFGs/d creates dietary imbalance; 6) pattern names (e.g., "white bread") may impugn RGFs, when names such as "unbalanced" or "few fruits and vegetables" may more fairly characterize the dietary imbalance; 7) avoidance of all enriched RGs may not only impair status of folate and other B vitamins and certain minerals such as iron and zinc but also decrease acceptability of WGFs; 8) extrapolation beyond median documented intakes in high-WGF consumers (∼48 g whole grain/d) in most cohorts is speculative; 9) recommended dietary patterns such as the Mediterranean diet demonstrate that the right mix of WGFs and RGFs contributes to positive health outcomes.

Whole-Grain Consumption Does Not Affect Obesity Measures: An Updated Systematic Review and Meta-analysis of Randomized Clinical Trials

Since the release of a previous meta-analysis on the effect of whole-grain intake on obesity measures, several clinical trials have been published. Therefore, we aimed to update the previous meta-analysis on the effect of whole-grain intake on obesity measures by including recently published studies, as well as considering the main limitations in that analysis. We searched the online databases of PubMed, Scopus, Clarivate Web of Science, EmBase, and Google Scholar for relevant studies published up to February 2019, using relevant keywords. Randomized clinical trials investigating the effect of whole-grain products or diets high in whole-grain foods, compared with a control diet, on anthropometric measures [including body weight, BMI, waist circumference, and fat mass (FM)] were included. In total, 21 studies with a total sample of 1798 participants, aged ≥18 years, were considered. Based on 22 effect sizes from 19 studies on body weight, with a total sample of 1698 adults, we found no significant effect of whole-grain consumption on body weight. The same findings were obtained for BMIs, such that using 10 effect sizes from 10 clinical trials with a total sample of 769 individuals we did not find any significant effect. With regards to body fat percentage [weighted mean difference (WMD): 0.27; 95% CI: -0.05 to 0.58%; P = 0.09], FM (WMD: 0.45; 95% CI: -0.12 to 1.02 kg; P = 0.12), fat-free mass (WMD: 0.31; 95% CI: -0.67 to 0.06 kg; P = 0.10), and waist circumference (WMD: 0.06; 95% CI: -0.50 to 0.63 cm; P = 0.82), we failed to find any significant effect of whole-grain consumption. In conclusion, our findings did not support current recommendations of whole-grain intake in attempts to control obesity measures. Given the beneficial effects of whole-grain intake on other measures of human health, additional well-designed studies are required to further investigate the effect on obesity. The protocol has been registered with PROSPERO (registration number CRD42019125320).

Latin American consumption of major food groups: Results from the ELANS study

BACKGROUND

The Latin American (LA) region is still facing an ongoing epidemiological transition and shows a complex public health scenario regarding non-communicable diseases (NCDs). A healthy diet and consumption of specific food groups may decrease the risk of NCDs, however there is a lack of dietary intake data in LA countries.

OBJECTIVE

Provide updated data on the dietary intake of key science-based selected food groups related to NCDs risk in LA countries.

DESIGN

ELANS (Latin American Study of Nutrition and Health) is a multicenter cross-sectional study assessing food consumption from an urban sample between15 to 65 years old from 8 LA countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela). Two 24-HR were obtained from 9,218 individuals. The daily intake of 10 food groups related to NCDs risk (fruits; vegetables; legumes/beans; nuts and seeds; whole grains products; fish and seafood; yogurt; red meat; processed meats; sugar-sweetened beverages (ready-to-drink and homemade)) were assessed and compared to global recommendations.

RESULTS

Only 7.2% of the overall sample reached WHO's recommendation for fruits and vegetables consumption (400 grams per day). Regarding the dietary patterns related to a reduced risk of NCDs, among the overall sample legumes and fruits were the food groups with closer intake to the recommendation, although much lower than expected (13.1% and 11.5%, respectively). Less than 3.5% of the sample met the optimal consumption level of vegetables, nuts, whole grains, fish and yogurt. Largest country-dependent differences in average daily consumption were found for legumes, nuts, fish, and yogurt. Mean consumption of SSB showed large differences between countries.

CONCLUSION

Diet intake quality is deficient for nutrient-dense food groups, suggesting a higher risk for NCDs in the urban LA region in upcoming decades. These data provide relevant and up-to-date information to take urgent public health actions to improve consumption of critically foods in order to prevent NCDs.

Factors Influencing British Adolescents' Intake of Whole Grains: A Pilot Feasibility Study Using SenseCam Assisted Interviews

High whole grain intake is beneficial for health. However, adolescents consume low levels of whole grain and the understanding of the underpinning reasons for this is poor. Using a visual, participatory method, we carried out a pilot feasibility study to elicit in-depth accounts of young people's whole grain consumption that were sensitive to their dietary, familial and social context. Furthermore, we explored barriers and suggested facilitators to whole grain intake and assessed the feasibility of using SenseCam to engage adolescents in research. Eight British adolescents (aged 11 to 16 years) wore a SenseCam device which auto-captured images every twenty seconds for three consecutive days. Participants then completed traditional 24-hour dietary recalls followed by in-depth interviews based on day three SenseCam images. Interview data were subjected to thematic analysis. Findings revealed that low adolescent whole grain intake was often due to difficulty in identifying whole grain products and their health benefits; and because of poor availability in and outside of the home. The images also captured the influence of parents and online media on adolescent daily life and choices. Low motivation to consume whole grains, a common explanation for poor diet quality, was rarely mentioned. Participants proposed that adolescent whole grain consumption could be increased by raising awareness through online media, improved sensory appeal, increased availability and variety, and tailoring of products for young people. SenseCam was effective in engaging young people in dietary research and capturing data relevant to dietary choices, which is useful for future research.

Rice and Prevention of Type 2 Diabetes: Narrative Review of Epidemiologic Evidene

Inspite that rice is a main staple and heaviliy consumed in most of Asian populations, health effect of rice has been less examined in nutritional epidemiologic studies compared to those of foods such as fruits, vegetables, meats and fish. Some recent meta-analyses that collected prospective cohort studies reported the associations between rice intake and incidence of and mortality from some chronic diseases especially type 2 diabetes. Concerning type 2 diabetes, the results are remarkably different between white (polished) rice and brown (unpolished) rice: the former increased and the latter decreased the risk. This difference may partly be explained by the different types and amounts of dietary fiber and different scores of dietary glycemic index. However, the results on dietary fiber and dietary glycemic index were not necessarily consistent. Indirect effect of rice intake has been examined through the studies on association of dietary patterns and breakfast skipping to type 2 diabetes. However, most of the results were inconclusive. Simple and straightforward judgement on the effect of rice to type 2 diabete should be avoided, and more nutritional epidemiologic studies with high research quality, including basic studies on dietary assessment, are needed, especially in Asian populations.

Glucose- and Lipid-Related Biomarkers Are Affected in Healthy Obese or Hyperglycemic Adults Consuming a Whole-Grain Pasta Enriched in Prebiotics and Probiotics: A 12-Week Randomized Controlled Trial

BACKGROUND

Synbiotic foods, which combine the action of prebiotics and probiotics along the gastrointestinal tract, can affect inflammatory and glucose-related markers.

OBJECTIVE

The aim of this study was to investigate the effects on inflammatory and glycemia-related markers of a whole-grain pasta containing barley β-glucans and Bacillus coagulans BC30, 6086 in healthy overweight or obese volunteers.

METHODS

A single-blind, parallel, randomized, placebo-controlled dietary intervention study was carried out. Forty-one healthy sedentary overweight (body mass index [BMI] 25-29.9 kg/m2) and obese (BMI ≥30) volunteers, aged 30-65 y and low consumers of fruit and vegetables, ate 1 serving/d of whole-grain control (CTR) or innovative (INN) pasta for 12 wk and maintained their habitual diets. Biological samples were collected at baseline and every 4 wk for primary (plasma high-sensitivity C-reactive protein [hs-CRP] and fasting plasma lipid profile) and secondary outcomes (glycemia-related markers, blood pressure, fecal microbiota composition, and body weight). Between (CTR compared with INN) and within (among weeks) group differences were tested for the whole population and for subgroups stratified by baseline values of BMI (≥30) and glycemia (≥100 mg/dL).

RESULTS

INN or CTR pasta consumption had no effect on primary and secondary outcomes over time, except for a significant increase in plasma γ-glutamyltransferase (GGT) after 12 wk of CTR pasta consumption. Comparisons between intervention groups revealed differences only at 12 wk: plasma GGT was higher in the CTR group; plasma hs-CRP, plasma LDL/HDL cholesterol ratio, and Bifidobacterium spp. were lower in the INN subgroup of obese volunteers; plasma resistin was lower and Faecalibacterium prausnitzii abundance was higher in the INN subgroup of hyperglycemic volunteers.

CONCLUSIONS

A daily serving of a synbiotic whole-grain pasta had limited effects on primary and secondary outcomes in the entire group of volunteers but affected glycemia- and lipid-related markers and resistin in a subgroup of healthy obese or hyperglycemic volunteers. This trial was registered at clinicaltrials.gov as NCT02236533.

Whole Grain Consumption for the Prevention and Treatment of Breast Cancer

Breast cancer is one of the most common and malignant cancers among females worldwide. Several epidemiological studies have indicated the inverse correlation between the intake of whole grains and the incidence of breast cancer. Whole grains are the most fundamental and important food source of bioactive phytochemicals, which have well-defined roles in the management of each stage of breast carcinogenesis. To better understand the value of whole grains in future prevention and treatment of breast cancer, the effects and possible mechanisms of six different whole grain cereals, which are the most commonly consumed throughout the world, are introduced in the current review. Moreover, the bioactive compounds extracted from whole grains are adequately formulated and the underlying mechanism of action is illustrated. In addition, the present limitations and future perspective of whole grain consumption for breast cancer are also concluded. The objective of this review is to promote the development of nutraceutical and functional food from whole grains and its application for reducing the risk of breast cancer.

Whole grain and cereal fiber intake and the risk of type 2 diabetes: a meta-analysis

In recent years, cardiovascular diseases (CVDs) have become a focus topic and global concern. There have been mixed reports on the relationship between whole grain or cereal fiber intake and the risk of type 2 diabetes. To evaluate whole grain or cereal intake on the risk of type 2 diabetes, we collected related literature on the relationship between whole grain or cereal fiber intake and the risk of type 2 diabetes. Methods: Eligible studies were identified from PubMed, Web of Science, and EBSCO (from 2007 to 2015). A total of three studies on whole grains were included, three studies about cereal fiber, and two on both whole grains and cereal fiber. We calculated the summary relative risks (RRs) using the random effects model. Eight studies contained 14,728 type 2 diabetes cases out of 434,903 subjects. Whole grain or cereal fiber intake is associated with type 2 diabetes (the overall RR was 0.68; 95% CI was 0.64-0.73) with significant heterogeneity in study-specific estimates (I2 =0%, P=0.452). Whole grain and cereal fiber intake are inversely associated with the risk of type 2 diabetes.

Decreased plasma serotonin and other metabolite changes in healthy adults after consumption of wholegrain rye: an untargeted metabolomics study

BACKGROUND

Wholegrain consumption has been associated with beneficial health effects including reduction of diabetes and cancer risk; however, the underlying mechanisms are not fully understood.

OBJECTIVE

The aim of this study was to characterize the effects of wholegrain rye intake on circulating metabolites in a human intervention study using untargeted metabolomics.

METHODS

The intervention consisted of 2 successive 4-wk periods in a randomized crossover design, where 15 adults consumed wholegrain rye bread (WGR) or white wheat bread enriched with fermented rye bran (WW+RB), following a 4-wk rye-free period with white wheat bread (WW). Fasting plasma samples were collected at the end of each period and analyzed using liquid chromatography-mass spectrometry. Metabolic profiles were compared to identify compounds discriminating WGR from the WW+RB and WW periods. Because peripheral serotonin is produced mainly in the gut, a hypothesis of its altered biosynthesis as a response to increased cereal fiber intake was tested by measuring intestinal serotonin of mice fed for 9 wk on a high-fat diet supplemented with different sources of fiber (rye bran flour, ground wheat aleurone, or powdered cellulose).

RESULTS

Five endogenous metabolites and 15 rye phytochemicals associated with WGR intake were identified. Plasma concentrations of serotonin, taurine, and glycerophosphocholine were significantly lower after the WGR than WW period (Q < 0.05). Concentrations of 2 phosphatidylethanolamine plasmalogens, PE(18:2/P-18:0) and PE(18:2/P-16:0), were lower after the WGR period than the WW+RB period (Q < 0.05). The concentration of serotonin was significantly lower in the colonic tissue of mice that consumed rye bran or wheat aleurone compared with cellulose (P < 0.001).

CONCLUSIONS

Wholegrain rye intake decreases plasma serotonin in healthy adults when compared with refined wheat. Intake of rye bran and wheat aleurone decreases colonic serotonin in mice. These results suggest that peripheral serotonin could be a potential link between wholegrain consumption and its associated health effects.Data used in the study were derived from a trial registered at www.clinicaltrials.gov as NCT03550365.

The Roles of Food Processing in Translation of Dietary Guidance for Whole Grains, Fruits, and Vegetables

The Dietary Guidelines for Americans (DGA) recommend the consumption of whole grains, fruits, and vegetables as part of a healthy diet. However, current consumption patterns suggest that most Americans are not meeting these recommendations. The challenge remains to align the DGA guidance with the food environment and consumers’ expectations for product quality, availability, and affordability. Currently, processed foods play an increasingly important role in American diets. Often characterized as unhealthy, processed foods are contributors to both food and nutritional security. When the alignment of processing strategies with DGA principles exists, achieving DGA goals is more likely, regardless of processing level. In this review, select processing strategies for whole grains, fruits, and vegetables are described to show how DGA principles can guide processing efforts to create healthier products. Although whole grains, supported by industry-wide innovation and guidance, have had some success with consumers, improving intake of fruit and vegetable products remains a challenge. Closing consumption gaps requires new innovations and products aligned with consumer preferences and DGA principles.

Document of recommendations of the SEA 2018. Lifestyle in cardiovascular prevention

Lifestyle is a complex concept that includes aspects external to ourselves that can modulate and influence our health. The knowledge of the relationship between lifestyle and cardiovascular risk does not attain the level of evidence achieved with clinical trials with drugs, because clinical studies are scarce and mainly of observational nature, albeit based on large cohorts. Nutritional epidemiology has the added difficulty of being based mostly on subjective dietary recall methods to ascertain nutrient and food intake over time, with the additional problems of incomplete data collection, variable measurements of adherence due to seasonal and geographical differences in food composition, and the changing eating behavior that human beings have over time. The purpose of this document is to carry out an updated and hierarchical review of the relationship between lifestyle and cardiovascular disease based on current evidence, paying attention to three aspects that are of great pathogenic importance and are directly modifiable: physical activity, tobacco consumption, and diet. With this, we intend to update the knowledge on this relationship, construct evidence-based recommendations, and provide a simple tool for clinical practice especially directed to health professionals involved in the care of people at cardiovascular risk, defining simple and easy strategies for individuals who receive advice for the primary and secondary prevention of cardiovascular diseases.

Second edition of SIMPAR's "Feed Your Destiny" workshop: the role of lifestyle in improving pain management

This review is aimed to summarize the latest data regarding pain and nutrition, which have emerged during the second edition of Feed Your Destiny (FYD). Theme presentations and interactive discussions were held at a workshop on March 30, 2017, in Florence, Italy, during the 9th Annual Meeting of Study in Multidisciplinary Pain Research, where an international faculty, including recognized experts in nutrition and pain, reported the scientific evidence on this topic from various perspectives. Presentations were divided into two sections. In the initial sessions, we analyzed the outcome variables and methods of measurement for health claims pertaining to pain proposed under Regulation EC No 1924/2006 of the European Parliament and of the Council of 20 December 2006 on nutrition and health claims made on foods. Moreover, we evaluated how the Mediterranean diet can have a potential impact on pain, gastrointestinal disorders, obesity, cancer, and aging. Second, we discussed the evidence regarding vitamin D as a nutraceutical that may contribute to pain control, evaluating the interindividual variability of pain nature and nurture, and the role of micro-RNAs (miRNAs), polyunsaturated omega 3 fatty acids, and phenolic compounds, with a final revision of the clinical role of nutrition in tailoring pain therapy. The key take-home message provided by the FYD workshop was that a balanced, personalized nutritional regimen might play a role as a synergic strategy that can improve management of chronic pain through a precision medicine approach.

Ferulic acid may target MyD88-mediated pro-inflammatory signaling - Implications for the health protection afforded by whole grains, anthocyanins, and coffee

Higher dietary intakes of anthocyanins have been linked epidemiologically to decreased risk for metabolic syndrome, type 2 diabetes and cardiovascular events; clinical trials and rodent studies evaluating ingestion of anthocyanin-rich extracts confirm favorable effects of these agents on endothelial function and metabolic syndrome. However, these benefits of anthocyanins are lost in rats whose gut microbiome has been eliminated with antibiotic treatment - pointing to bacterial metabolites of anthocyanins as the likely protective agents. A human pharmacokinetic assessment of orally administered cyanidin-3-O-glucoside, a prominent anthocyanin, has revealed that, whereas this compound is minimally absorbed, ferulic acid (FA) is one of its primary metabolites that appears in plasma. FA is a strong antioxidant and phase 2 inducer that has exerted marked anti-inflammatory effects in a number of rodent and cell culture studies; in particular, FA is highly protective in rodent models of diet-induced weight gain and metabolic syndrome. FA, a precursor for lignan synthesis, is widely distributed in plant-based whole foods, mostly in conjugated form; whole grains are a notable source. Coffee ingestion boosts plasma FA owing to gastrointestinal metabolism of chlorogenic acid. Hence, it is reasonable to suspect that FA mediates some of the broad health benefits that have been associated epidemiologically with frequent consumption of whole grains, anthocyanins, coffee, and unrefined plant-based foods. The molecular basis of the anti-inflammatory effects of FA may have been clarified by a recent study demonstrating that FA can target the adaptor protein MyD88; this plays an essential role in pro-inflammatory signaling by most toll-like receptors and interleukin-1β. If feasible oral intakes of FA can indeed down-regulate MyD88-dependent signaling, favorable effects of FA on neurodegeneration, hypothalamic inflammation, weight gain, adipocyte and beta cell function, adiponectin secretion, vascular health, and cartilage and bone integrity can be predicted. Since FA is well tolerated, safe, and natural, it may have great potential as a protective nutraceutical, and clinical trials evaluating its effects are needed.

Dietary and genetic risk scores and incidence of type 2 diabetes

Background

Both lifestyle and genetic predisposition determine the development of type 2 diabetes (T2D), and studies have indicated interactions between specific dietary components and individual genetic variants. However, it is unclear whether the importance of overall dietary habits, including T2D-related food intakes, differs depending on genetic predisposition to T2D. We examined interaction between a genetic risk score for T2D, constructed from 48 single nucleotide polymorphisms identified in genome-wide association studies, and a diet risk score of four foods consistently associated with T2D in epidemiological studies (processed meat, sugar-sweetened beverages, whole grain and coffee). In total, 25,069 individuals aged 45–74 years with genotype information and without prevalent diabetes from the Malmö Diet and Cancer cohort (1991–1996) were included. Diet data were collected with a modified diet history method.

Results

During 17-year follow-up, 3588 incident T2D cases were identified. Both the diet risk score (HR in the highest risk category 1.40; 95% CI 1.26, 1.58; P trend = 6 × 10⁻¹⁰) and the genetic risk score (HR in the highest tertile of the genetic risk score 1.67; 95% CI 1.54, 1.81; P trend = 7 × 10⁻³⁵) were associated with increased incidence of T2D. No significant interaction between the genetic risk score and the diet risk score (P = 0.83) or its food components was observed. The highest risk was seen among the 6% of the individuals with both high genetic and dietary risk scores (HR 2.49; 95% CI 2.06, 3.01).

Conclusions

The findings thus show that both genetic heredity and dietary habits previously associated with T2D add to the risk of T2D, but they seem to act in an independent fashion, with the consequence that all individuals, whether at high or low genetic risk, would benefit from favourable food choices.

Electronic supplementary material

The online version of this article (10.1186/s12263-018-0599-1) contains supplementary material, which is available to authorized users.

Characterization of the Degree of Food Processing in Relation With Its Health Potential and Effects

Up today technological processes are intended to produce safe and palatable food products. Yet, it is also expected that processing produces healthy and sustainable foods. However, due to the dramatic increase of chronic diseases prevalence worldwide, i.e., obesity, type 2 diabetes, cardiovascular diseases, and some cancers, ultraprocessing has been pointed out as producing unhealthy foods, rich in energy and poor in protective micronutrients and fiber, i.e., "empty" calories. Indeed the 1980s saw massive arrivals of ultraprocessed foods in supermarkets, i.e., fractionated-recombined foods with added ingredients and/or additives. Epidemiological studies clearly emphasized that populations adhering the most to ultraprocessed foods, e.g., processed meat, refined grains, ultraprocessed plant-based foods, and/or sweetened beverages, exhibited the higher prevalence of chronic diseases. This prompted researchers to classify foods according to their degree of processing as with the international NOVA classification (i.e., un/minimally processed, processed, and ultraprocessed foods). More and more studies showed that such a classification makes sense for health. Overall one distinguishes three categories of processes: mechanical, thermal, and fermentative treatments, this latter being the more favorable to food health potential. This chapter has therefore several ambitions: (1) to review association between degree of food processing and chronic disease risk prevalence; (2) to explore the impact of technological processes on food health potential considering both matrix and compositional effects; (3) to discuss the need for classifying food according to their degree of processing in future epidemiological studies; and (4) to analyze consequences of adhering to a more holistic paradigm in both food processing and nutrition.

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 between dietary protein intake and type 2 diabetes varies by dietary pattern

BACKGROUND

Epidemiological studies have demonstrated that high total protein intake was related to type 2 diabetes mellitus (T2DM) risks. However, few studies considered the impact of dietary pattern.

OBJECTIVE

We examined the associations between protein intake and T2DM in different dietary patterns.

METHODS

We used the demographic and dietary information of adults aged 18-75 years from the China Health and Nutrition Survey (2009), consisting of 4113 women and 4580 men. Dietary data was collected by using 24-h recalls combined with a food inventory for 3 consecutive days. Cluster analysis was used to classify subjects into groups, as determined by major sources of protein. Logistic regression models were used to calculate odds ratios (OR) and 95% confidence interval (95% CI) of T2DM according to the energy-adjusted protein intake.

RESULTS

All participants were divided into three patterns according to the dietary source of protein (legumes and seafood, red meat, refined grains). Overall, plant protein intake was significantly and inversely associated with T2DM. In the subgroup analysis by dietary patterns, extreme quartile of plant protein intake was also inversely related to T2DM in the "legumes and seafood" group [OR = 0.58, 95% CI (0.33-0.96)]. Total protein intake and animal protein intake were positively related to T2DM in the "red meat" group [OR: 3.12 (1.65-5.91) and 3.48 (1.87-6.60), respectively]. However, the association of animal protein intake was reversed in the "refined grains" group [OR = 0.55, 95% CI 0.32-0.89].

CONCLUSIONS

The association between protein intake and T2DM varies by dietary pattern. Dietary pattern may be considered into the recommendation of protein intake for diabetes prevention.

Dietary patterns are associated with type 2 diabetes mellitus among middle-aged adults in Zhejiang Province, China

Background

Although some studies have shown the associations between dietary patterns and the risk T2DM in a general population, the associations in middle-aged Chinese have been rarely studied to date. In this study, we aimed to characterize dietary patterns in Chinese adults aged 45-59y (n = 1918) and to evaluate the relationship between dietary patterns and the risk of T2DM.

Methods

The study population was a part of the population-based the Nutrition and Health Study conducted in the city of Hangzhou, Zhejiang Province, China. Dietary intake was assessed by using a validated food frequency questionnaire (FFQ). Multivariate logistic regression analyses were used to estimate the associations between dietary patterns and the risk of T2DM, adjusting for potential confounders.

Results

Three major dietary patterns were identified using factor analysis, including the traditional southern Chinese, the Western, and the grains-vegetables patterns. After adjusting for the potential confounders, subjects in the highest quartile of the Western dietary pattern scores had greater odds ratio(OR) for T2DM(OR = 1.28; 95% confidence interval (CI): 1.103–1.697; P = 0.02) than did those in the lowest quartile. Compared with those in the lowest quartile, subjects in the highest quartile of the grains-vegetables dietary pattern scores had a lower OR for T2DM (OR = 0.72; 95% CI:0.596–0.952; P = 0.04). Moreover, no significant association was found between the traditional southern Chinese dietary pattern and risk of developing T2DM.

Conclusions

Our findings indicated that the Western dietary pattern was associated with an elevated risk, whereas the grains-vegetables dietary pattern was associated with a reduced risk of T2DM. Further researches are needed to confirm these findings.

Impact of sourdough fermentation on appetite and postprandial metabolic responses - a randomised cross-over trial with whole grain rye crispbread

Sourdough fermentation is considered to have beneficial effects on postprandial satiety and metabolic responses, but studies demonstrating effects at physiological conditions are lacking. The aim of this acute breakfast intervention study was to determine the effect of consumption of sourdough-fermented and unfermented rye crispbread on self-rated appetite, postprandial glucose and insulin response in healthy subjects. In all, twenty-four Swedish adults were included in a single-blinded, randomised cross-over trial. Three crispbreads (sourdough-fermented and unfermented whole grain rye and yeast-fermented refined wheat as control) were consumed as part of a standardised breakfast. Subjective appetite score, assessed using visual analogue scale, and plasma glucose and insulin concentrations were measured at baseline and postprandially until 360 and 240 min, respectively. Structural changes and viscosity during mastication and gastric digestion were investigated using in vitro methods. Hunger and desire to eat were lower (P<0·05) based on AUC measurements after intake of sourdough-fermented rye crispbread compared with after intake of yeast-fermented refined wheat crispbread. On the basis of AUC (0-230 min), insulin response was lowest after intake of unfermented rye crispbread compared with sourdough-fermented rye and yeast-fermented refined wheat crispbread. Degradation of viscous fibres and faster bolus disintegration for the sourdough-fermented bread may partly explain the less favourable metabolic responses compared with unfermented bread. Our results showed that food processing affects the composition and structural characteristics of rye bread, which has implications for appetite and metabolic responses.

Consumption of whole grains, fruit and vegetables is not associated with indices of renal function in the population-based longitudinal Doetinchem study

Emerging evidence suggests that diet and renal function are related. Little is known, however, about the association of consumption of whole grains, fruit and vegetables with urinary albumin:creatinine ratio (ACR) and changes in estimated glomerular filtration rate (eGFR). We investigated this in a population-based cohort aged 26-65 years. Data were from 3787 participants from the Doetinchem cohort study, who were examined ≥3 times, 5 years apart. Consumption of food groups was assessed at each round with a validated FFQ. GFR was estimated at each round from routinely measured cystatin C and creatinine using the Chronic Kidney Disease-Epidemiology (CKD-EPI) equation. ACR was measured at the last round. Generalised estimated equation models were performed to examine associations with changes in eGFR. Linear regression was used to examine associations with ACR. Adjustments were made for covariates related to lifestyle, biological factors and diet. Mean baseline eGFR was 104·5 (sd 13·7) and mean annual decline was -0·95 (sd 0·67) ml/min per 1·73 m2 over a 15-year follow-up. A trend was observed towards slightly less annual decline in eGFR among those with higher consumption of whole grains (P=0·06). This association, however, was attenuated and no longer significant in multivariate models (P=0·29). Consumption of fruit and vegetables was not associated with changes in eGFR and urinary ACR. In conclusion, consumption of whole grains, fruit and vegetables is not associated with changes in eGFR and mean ACR. As this was the first longitudinal study into this association in the general population, and as results are only partially in line with related studies, further research is recommended.

Perspective: A Definition for Whole-Grain Food Products-Recommendations from the Healthgrain Forum

Whole grains are a key component of a healthy diet, and enabling consumers to easily choose foods with a high whole-grain content is an important step for better prevention of chronic disease. Several definitions exist for whole-grain foods, yet these do not account for the diversity of food products that contain cereals. With the goal of creating a relatively simple whole-grain food definition that aligns with whole-grain intake recommendations and can be applied across all product categories, the Healthgrain Forum, a not-for-profit consortium of academics and industry working with cereal foods, established a working group to gather input from academics and industry to develop guidance on labeling the whole-grain content of foods. The Healthgrain Forum recommends that a food may be labeled as "whole grain" if it contains ≥30% whole-grain ingredients in the overall product and contains more whole grain than refined grain ingredients, both on a dry-weight basis. For the purposes of calculation, added bran and germ are not considered refined-grain ingredients. Additional recommendations are also made on labeling whole-grain content in mixed-cereal foods, such as pizza and ready meals, and a need to meet healthy nutrition criteria. This definition allows easy comparison across product categories because it is based on dry weight and strongly encourages a move from generic whole-grain labels to reporting the actual percentage of whole grain in a product. Although this definition is for guidance only, we hope that it will encourage more countries to adopt regulation around the labeling of whole grains and stimulate greater awareness and consumption of whole grains in the general population.

Intake of different dietary proteins and risk of type 2 diabetes in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

The roles of different dietary proteins in the aetiology of type 2 diabetes (T2D) remain unclear. We investigated the associations of dietary proteins with the risk of incident T2D in Finnish men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study. The study included 2332 men aged 42–60 years at the baseline examinations in 1984–1989. Protein intakes were calculated from 4-d dietary records. Incident T2D was determined by self-administered questionnaires, fasting blood glucose measurements, 2-h oral glucose tolerance tests, and with national registers. The multivariable-adjusted risk of T2D on the basis of protein intakes was compared by the Cox proportional hazard ratios (HR). During the mean follow-up of 19·3 years, 432 incident T2D cases were identified. Total, animal, meat or dairy product protein intakes were not associated with risk of T2D when the potential confounders were accounted for. Plant (multivariable-adjusted extreme-quartile HR 0·65; 95 % CI 0·42, 1·00; Ptrend 0·04) and egg (HR 0·67; 95 % CI 0·44, 1·00; Ptrend 0·03) protein intakes were associated with a decreased risk of T2D. Adjustments for BMI, plasma glucose and serum insulin slightly attenuated associations. Replacing 1 % energy from carbohydrates with energy from protein was associated with a 5 % (95 % CI 0, 11) increased risk of T2D, but adjustment for fibre intake attenuated the association. Replacing 1 % of energy from animal protein with energy from plant protein was associated with 18 % (95 % CI 0, 32) decreased risk of T2D. This association remained after adjusting for BMI. In conclusion, favouring plant and egg proteins appeared to be beneficial in preventing T2D.

Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies

The aim of this systematic review and meta-analysis was to synthesize the knowledge about the relation between intake of 12 major food groups and risk of type 2 diabetes (T2D). We conducted a systematic search in PubMed, Embase, Medline (Ovid), Cochrane Central, and Google Scholar for prospective studies investigating the association between whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSB) on risk of T2D. Summary relative risks were estimated using a random effects model by contrasting categories, and for linear and non-linear dose–response relationships. Six out of the 12 food-groups showed a significant relation with risk of T2D, three of them a decrease of risk with increasing consumption (whole grains, fruits, and dairy), and three an increase of risk with increasing consumption (red meat, processed meat, and SSB) in the linear dose–response meta-analysis. There was evidence of a non-linear relationship between fruits, vegetables, processed meat, whole grains, and SSB and T2D risk. Optimal consumption of risk-decreasing foods resulted in a 42% reduction, and consumption of risk-increasing foods was associated with a threefold T2D risk, compared to non-consumption. The meta-evidence was graded “low” for legumes and nuts; “moderate” for refined grains, vegetables, fruit, eggs, dairy, and fish; and “high” for processed meat, red meat, whole grains, and SSB. Among the investigated food groups, selecting specific optimal intakes can lead to a considerable change in risk of T2D.