Whole grain rye intake, reflected by a biomarker, is associated with favorable blood lipid outcomes in subjects with the metabolic syndrome--a randomized study

Nutrient intake and adherence to the Nordic nutrition recommendations in a Swedish cohort with abdominal obesity

BACKGROUND

The Nordic Nutrition Recommendations (NNR) are developed to promote public health and to prevent food-related diseases such as obesity and cardiovascular diseases.

OBJECTIVE

To investigate the nutrient intake and adherence to the NNR in a Swedish cohort with abdominal obesity.

DESIGN

Dietary intake data were collected using 3-day food diaries and anthropometry and clinical chemistry parameters were measured at baseline of a long-term intervention studying weight-loss management.

RESULTS

Eighty-seven subjects with abdominal obesity successfully completed a 3-day food diary. Twelve of these subjects were excluded for further analysis due to implausible low-energy reporting. The remaining 75 subjects (76% females) had mean age of 52.3 ± 10.1 years and a mean body mass index of 34.3 ± 3.1 kg/m2. Mean total fat intake (41.2 ± 7.0E%) was exceeded by 56% of the sample size compared to the maximum recommended intake (RI) of 40E%, whereas mean carbohydrate intake (40.4 ± 8.0E%) was lower than the RI (45-60E%). The intake of saturated fatty acids was high compared to the NNR with only 2 women and none of men reported intakes within the RI of <10 E%. Adherence to the RI for dietary fibre was very low (16.0% and 13.3% when expressed as g/d and g/MJ, respectively). Analyses of micronutrient intake showed lowest adherences for vitamin D and sodium.

CONCLUSIONS

The nutrient intake in our subjects compared to NNR was rather low with a high total fat intake, particularly too high intake of saturated fatty acids, high salt consumption, and very low dietary fibre and vitamin D intake. More effort is clearly needed to promote healthy dietary habits among subjects with obesity.

Dietary assessment of type 2 diabetic patients using healthful plant-based diet score in the Eastern Province of Saudi Arabia

BACKGROUND

Diabetes mellitus is a chronic disease characterized by a wide range of metabolic problems. The current study sought to assess nutritional habits of Saudi patients with type 2 diabetes (T2D) and to propose recommendations to improve these patients' dietary habits and delay possible disease complications.

METHODS

Over a period of three years, (2017-2019) 577 patients with T2D attending the outpatient's diabetic clinics at King Fahd Hospital of the University, Al Khobar, Saudi Arabia were invited to participate in this study. Data of dietary intake were collected by trained nurses using a pretested structured validated semi quantitative food frequency questionnaire. The dietary data were collected using 7-day dietary recall questionnaire. A modified score system that associates dietary habits with glycemic control and lipid profile was used.

RESULTS

Overall, a high healthful plant-based diet score was associated with a significant (P = 0.018) reduction in triglycerides (TG) level (mean difference - 3.78%; 95% CI, -0.65% to -6.81%) and a statistically non-significant (P = 0.06) increase in high density lipoprotein (HDL) levels (mean difference 1.87%; 95% CI -0.06-3.84%) in T2D patients from the Eastern Province of Saudi Arabia. Additionally, in our patient group, the prevalence of coronary artery disease, stroke, peripheral artery disease, and chronic kidney disease in T2D patients was 11.3%, 6.2%, 3.3%, and 8.4%, respectively and were higher when compared to the prevalence in the general population.

CONCLUSION

The present study showed that adherence to a healthful plant-based diet, when compared to high glycemic index diet, is associated with a favorable outcome in glycemic control and lipid profile in T2D patients. Prior assessment of total diet quality may be beneficial when giving nutritional advice to T2D patients with the possibility of improving glycemic control and lipid profile.

Effects of a wholegrain-rich diet on markers of colonic fermentation and bowel function and their associations with the gut microbiome: a randomised controlled cross-over trial

Background

Diets rich in whole grains are associated with health benefits. Yet, it remains unclear whether the benefits are mediated by changes in gut function and fermentation.

Objective

We explored the effects of whole-grain vs. refined-grain diets on markers of colonic fermentation and bowel function, as well as their associations with the gut microbiome.

Methods

Fifty overweight individuals with increased metabolic risk and a high habitual intake of whole grains (~69 g/day) completed a randomised cross-over trial with two 8-week dietary intervention periods comprising a whole-grain diet (≥75 g/day) and a refined-grain diet (<10 g/day), separated by a washout period of ≥6  weeks. A range of markers of colonic fermentation and bowel function were assessed before and after each intervention.

Results

The whole-grain diet increased the levels of faecal butyrate (p = 0.015) and caproate (p = 0.013) compared to the refined-grain diet. No changes in other faecal SCFA, BCFA or urinary levels of microbial-derived proteolytic markers between the two interventions were observed. Similarly, faecal pH remained unchanged. Faecal pH did however increase (p = 0.030) after the refined-grain diet compared to the baseline. Stool frequency was lower at the end of the refined-grain period compared to the end of the whole-grain diet (p = 0.001). No difference in faecal water content was observed between the intervention periods, however, faecal water content increased following the whole-grain period compared to the baseline (p = 0.007). Dry stool energy density was unaffected by the dietary interventions. Nevertheless, it explained 4.7% of the gut microbiome variation at the end of the refined-grain diet, while faecal pH and colonic transit time explained 4.3 and 5%, respectively. Several butyrate-producers (e.g., Faecalibacterium, Roseburia, Butyriciococcus) were inversely associated with colonic transit time and/or faecal pH, while the mucin-degraders Akkermansia and Ruminococcaceae showed the opposite association.

Conclusion

Compared with the refined-grain diet, the whole-grain diet increased faecal butyrate and caproate concentrations as well as stool frequency, emphasising that differences between whole and refined grains affect both colonic fermentation and bowel habits.

The Effect of Rye-Based Foods on Postprandial Plasma Insulin Concentration: The Rye Factor

Consumption of whole grain has been associated with lower incidence of type-2 diabetes, cardiovascular disease and their risk factors including improved glycemic control. In comparison with other whole grain products, rye bread has been shown to induce lower insulin response in the postprandial phase, without affecting the glucose response. This phenomenon has been referred to as the “rye factor” and is being explored in this review where we summarize the findings from meal and extended meal studies including rye-based foods. Overall, results from intervention studies showed that rye-based foods vs. (wheat) control foods had positive effect on both insulin and glucose responses in the postprandial phase, rather than on insulin alone. Mechanistic studies have shown that the rye factor phenomenon might be due to slowing of the glucose uptake in the intestine. However, this has also been shown for wheat-based bread and is likely an effect of structural properties of the investigated foods rather than the rye per se. More carefully controlled studies where standardized structural properties of different cereals are linked to the postprandial response are needed to further elucidate the underlying mechanisms and determinants for the effect of specific cereals and product traits on postprandial glycemic control.

Wholegrain intake, growth and metabolic markers in Danish infants and toddlers: a longitudinal study

PURPOSE

Wholegrain intake is linked to lower risk of lifestyle diseases, but little is known about its role in growth and metabolic health during the first years of life. We characterized wholegrain and dietary fibre intake in 439 Danish children at 9 and 36 months of age and explored associations with height z-scores (HAZ), body mass index z-scores (BMIZ) and metabolic markers.

METHODS

We used pooled data from two infant cohorts and estimated intakes of total wholegrain, dietary fibre and wholegrain subtypes from 7-day dietary records. Associations with HAZ, BMIZ and non-fasting plasma low-density (LDLC) and high-density-lipoprotein cholesterol, triacylglycerol, insulin and glucose were analysed in mixed models, adjusted for potential confounders.

RESULTS

Median (25th, 75th percentile) wholegrain intake was 7.5 (4.9, 10.5) and 6.5 (4.6, 9.0) g/MJ at 9 and 36 months. Neither wholegrain nor dietary fibre intake were associated with HAZ (P ≥ 0.09). At 36 months, wholegrain intake was inversely associated with LDLC (P = 0.05) and directly with glucose (P < 0.001). In secondary analyses, wholegrain rye was inversely associated with glucose at 9 months and insulin at 36 months (both P ≤ 0.03). Oat and wheat wholegrain were directly associated with glucose (both P ≤ 0.01) and wheat with BMIZ (P = 0.02) at 36 months.

CONCLUSION

Danish infants and toddlers have high intakes of wholegrain and dietary fibre, with no indication of compromised growth. In line with studies in adults, wholegrain intake was inversely associated with LDLC. The observed direct association between wholegrain intake and plasma glucose and associations with wholegrain subtypes should be investigated further.

Diet Quality, Physical Activity, and Weight Changes and Their Association With 6-Year Risk of Metabolic Syndrome in Mexican Adults

Background. Among lifestyle factors, obesity has been postulated as the most important risk factor for metabolic syndrome (MS). Lifestyle factors such as physical activity (PA), diet quality, and weight management are so closely related, it is not clear if the role of lifestyle factors is exclusively through its effect on weight, or if they contribute independently. Objective. To examine the effect of lifestyle factors such as diet quality, weight change, and leisure time PA on MS occurrence in lean and overweight/obese (OW/OB) adults over a 6-year period. Methods. This was a longitudinal analysis of data from adults participating in the Health Workers Cohort Study. Results. A total of 1046 participants were included; 37.2% of the OW/OB group and 16.2% of the lean participants developed MS. Becoming overweight had a hazard ratio (HR) of 3.06 for developing MS compared with remaining lean (95% CI = 1.98, 4.74). Going from OW/OB to lean was associated with lower risk of MS (HR = 0.41; 95% CI = 0.22, 0.79). Among OW/OB, becoming active was associated with lower risk (HR = 0.63; 95% CI = 0.42, 0.95) in comparison with an inactive pattern; diet quality was not associated with occurrence of MS. Conclusion. Weight change was the most relevant factor predicting MS over a 6-year period.

Preliminary Study on Pasta Samples Characterized in Antioxidant Compounds and Their Biological Activity on Kidney Cells

Pasta is one of the basic foods of the Mediterranean diet and for this reason it was chosen for this study to evaluate its antioxidant properties. Three types of pasta were selected: buckwheat, rye and egg pasta. Qualitative-quantitative characterization analyses were carried out by HPLC-DAD to identify antioxidant compounds. The data showed the presence of carotenoids such as lutein and polyphenols such as indoleacetic acid, (carotenoids from 0.08 to 0.16 mg/100 g, polyphenols from 3.7 to 7.4 mg/100 g). To assess the effect of the detected metabolites, in vitro experimentation was carried out on kidney cells models: HEK-293 and MDCK. Standards of β-carotene, indoleacetic acid and caffeic acid, hydroalcoholic and carotenoid-enriched extracts from samples of pasta were tested in presence of antioxidant agent to determine viability variations. β-carotene and indoleacetic acid standards exerted a protective effect on HEK-293 cells while no effect was detected on MDCK. The concentrations tested are likely in the range of those reached in body after the consumption of a standard pasta meal. Carotenoid-enriched extracts and hydroalcoholic extracts showed different effects, observing rescues for rye pasta hydroalcoholic extract and buckwheat pasta carotenoid-enriched extract, while egg pasta showed milder dose depending effects assuming pro-oxidant behavior at high concentrations. The preliminary results suggest behaviors to be traced back to the whole phytocomplexes respect to single molecules and need further investigations.

Impact of a Fermented High-Fiber Rye Diet on Helicobacter pylori and Cardio-Metabolic Risk Factors: A Randomized Controlled Trial Among Helicobacter pylori-Positive Chinese Adults

Background: High dietary fiber intake has been associated with reduced risk of Helicobacter pylori infection and co-morbidities such as gastric cancer but also with reduced risk of cardiovascular disease. It has been suggested that fermented rye could affect Helicobacter pylori bacterial load and that high- fiber rye may be superior to wheat for improvement of several cardiometabolic risk factors, but few long-term interventions with high fiber rye foods have been conducted. Objective: To examine the effect of high-fiber wholegrain rye foods with added fermented rye bran vs. refined wheat on Helicobacter pylori infection and cardiometabolic risk markers in a Chinese population with a low habitual consumption of high fiber cereal foods. Design: A parallel dietary intervention was set up and 182 normal- or overweight men and women were randomized to consume wholegrain rye products containing fermented rye bran (FRB) or refined wheat (RW) for 12 weeks. Anthropometric measurements, fasting blood sample collection and ¹³C-urea breath test (¹³C-UBT) were performed at baseline and after 6 and 12 weeks of intervention as well as 12 weeks after the end of the intervention. Results: No difference between diets on Helicobacter pylori bacterial load measured by ¹³C-UBT breath test or in virulence factors of Helicobacter pylori in blood samples were found. Low density lipoprotein cholesterol (LDL-C) and high sensitivity C-reactive protein (hs-CRP) were significantly lower in the FRB group, compared to the RW group after 12 weeks of intervention. The intervention diets did not affect markers of glucose metabolism or insulin sensitivity. Conclusions: While the results of the present study did not support any effect of FRB on Helicobacter pylori bacterial load, beneficial effects on LDL-C and hs-CRP were clearly shown. This suggest that consumption of high fiber rye foods instead of refined wheat could be one strategy for primary prevention of cardiovascular disease. Clinical Trial Registration: The trial was registered at www.clinicaltrials.gov, Identifier: NCT03103386.

Long-term association of red meat consumption and lipid profile: A 13-year prospective population-based cohort study

OBJECTIVES

The long-term associations between red meat consumption and lipid profile are not completely known. This longitudinal study assessed the association of red meat consumption with lipid profile in healthy Iranian adults using repeated measurements of red meat intake.

METHODS

The population-based longitudinal study was conducted within the framework of the Isfahan Cohort Study on a subsample of 1376 healthy adults, aged ≥35 y, for whom complete information was available in all three phases of the study. A simplified qualitative 48-item food frequency questionnaire, blood pressure, anthropometric measurements, and fasting serum lipids and blood sugar were evaluated in three phases. Mixed-effects linear regression was applied to examine the longitudinal associations between red meat consumption and lipid profile.

RESULTS

After adjustment for potential confounders, each single-serving increase in red meat and organ meat consumption was significantly associated with an increment in triacylglycerol (β = 6.30; 95% confidence interval [CI], 3.97-8.63), total cholesterol (β = 3.03; 95% CI, 2.02-4.04), low-density lipoprotein (β = 3.40; 95% CI, 2.64-4.17), high-density lipoprotein (β = 0.60; 95% CI, 0.28-0.93), ratio of low-density to high-density lipoprotein (β = 0.03; 95% CI, 0.01-0.05), and non-high-density lipoprotein (β = 2.42; 95% CI, 1.41-3.43). However, processed meat consumption had no significant association with lipid profile.

CONCLUSIONS

Total red meat intake had a significant, direct association with lipid profile after a 13-year follow-up period in a cohort of the healthy Iranian population.

Whole grain food diet slightly reduces cardiovascular risks in obese/overweight adults: a systematic review and meta-analysis

BACKGROUND

The effects of whole grain diet on cardiovascular risks in obese and overweight adults is not well established. Our goal was to conduct a systematic review and meta-analysis on the effect of whole grain diet on cardiovascular risks in obese/overweight adults.

METHODS

PubMed, Embase and Cochrane were systematically scanned for randomized controlled trials (RCTs), and studies were selected based on certain inclusion and exclusion criteria. The primary outcome was the effectiveness of whole grain food consumption in reducing body weight. The secondary outcomes were the effect of whole grain food consumption on cardiovascular disease (CVD) risk factors including plasma low-density lipoprotein cholesterol (LDL-C), insulin resistance index, blood pressure, body mass index (BMI), C-reactive protein (CRP), and waist circumference in obese/overweight adults.

RESULTS

Our results showed that whole grain consumption was associated with lower body weight (mean difference (MD) = - 0.5, 95% confidence intervals (CI) [- 0.74, 0.25], I2 = 35%, P < 0.0001) and lower CRP (MD = -0.36, 95% CI [- 0.54, - 0.18], I2 = 69%, P < 0.0001), compared with the control group. However, there were no significant differences in LDL-C (MD = -0.08, 95% CI [- 0.16, 0.00], I2 = 27%, P = 0.05), waist circumference (MD = -0.12, 95% CI [- 0.92, 0.68], I2 = 44%, P = 0.76), systolic blood pressure (MD = -0.11, 95% CI [- 1.55, 1.33], I2 = 3%, P = 0.88), diastolic blood pressure (MD = -0.44, 95% CI [- 1.44, 0.57], I2 = 15%, P = 0.39), and fasting glucose (MD = -0.05, 95% CI [- 0.12, 0.01], I2 = 31%, P = 0.11) between the two groups.

CONCLUSION

This study suggests that whole grain food consumption can slightly reduce body weight and CRP in obese/overweight population.

The healthy Nordic diet for blood glucose control: a systematic review and meta-analysis of randomized controlled clinical trials

AIMS

Investigations on the possible effect of the Nordic diet (ND) on the glycemic control and the risk of diabetes have led to inconsistent results. The present study tried to determine the effect of the ND on the markers of blood glucose control using a systematic review and meta-analysis of randomized controlled clinical trials (RCTs).

METHODS

Predefined keywords were used to search PubMed, ISI Web of Science, Scopus and Google Scholar up to April 2019. The random effects model was used to compute the overall estimates.

RESULTS

In total, six RCTs with 618 participants (6-26 weeks of follow-up period) were included in the present study. The meta-analysis revealed that the ND might not have a considerable effect on fasting blood glucose levels [weighted mean difference (WMD) = -0.05 mmol/l, 95% CI - 0.13, 0.01, P = 0.112]. In contrast, the analyses showed that the ND significantly reduces serum insulin concentrations (WMD = -1.12 mU/l, 95% CI - 1.84, - 0.39, P = 0.002) and the homeostasis model assessment for insulin resistance (HOMA-IR) (WMD = - 0.34, 95% CI - 0.53, - 0.14, P = 0.001) compared to control diets. The effect on serum insulin levels was sensitive to one of the included studies. This dietary pattern did not significantly affect 2-h post-prandial blood glucose and Matsuda index.

CONCLUSIONS

Adherence to the ND might improve serum insulin and HOMA-IR levels; however, this effect was not confirmed for other markers of blood glucose control. Future well-designed and long-term clinical trials are highly recommended.

Quantitative assessment of betainized compounds and associations with dietary and metabolic biomarkers in the randomized study of the healthy Nordic diet (SYSDIET)

BACKGROUND

Recently, a group of betainized compounds have been suggested to play a role in health effects in relation to a whole-grain-rich diet.

OBJECTIVES

The aims of this study were to develop a quantitative mass spectrometric method for selected betainized compounds in human plasma, and to investigate their association with nutrient intake and measures of metabolic health in participants of the SYSDIET study.

METHODS

The SYSDIET study was a controlled randomized intervention including individuals with metabolic syndrome, where the healthy Nordic diet (HND) group increased intakes of whole grains, canola oil, berries, and fish, whereas the control diet (CD) group consumed low-fiber cereal products, milk fat, and restricted amounts of fish and berries. A quantitative LC combined with triple quadrupole MS method for betainized compounds was developed and applied to fasting plasma samples from baseline (week 0) and the end of the intervention (week 18 or 24). Concentrations of betainized compounds were correlated with intakes of selected nutrients and fiber and measures of metabolic health.

RESULTS

Pipecolic acid betaine (PAB) concentrations were significantly higher in the HND group than in the CD group (P = 0.00032) at the end of the intervention and correlated directly (P < 0.0001) with intakes of dietary fiber (r = 0.376) and a biomarker related to whole-grain rye intake, namely the ratio of alkylresorcinol C17:0 to C21:0 (r = 0.442). PAB was associated inversely with fasting plasma insulin consistently at the beginning and at the end of the intervention (P < 0.001, r = -0.300; P < 0.01, r = -0.250, respectively), as well as IL-1 receptor antagonist (P < 0.01, r = -0.232 at the beginning; P < 0.01, r = -0.236 at the end) and serum LDL/HDL cholesterol (P < 0.01, r = -0.239 at the beginning; P < 0.01, r = -0.241 at the end).

CONCLUSIONS

Among adults with the metabolic syndrome, PAB plasma concentrations were associated with fasting insulin, inflammation, and lipids and were significantly increased with adoption of the HND. Further studies are needed to clarify the biological functions of betainized compounds. This trial was registered at clinicaltrials.gov as NCT00992641.

Biomarkers of cereal food intake

Background/objectives

Cereal foods are major contributors to the daily energy, protein, and dietary fiber intake all over the world. The role of cereals in human health is dependent on whether they are consumed as refined or whole grain and on cereal species. To unravel the underlying mechanisms of health effects attributed to specific cereal foods and to provide more precise dietary advice, there is a need for improved dietary assessment of whole-grain intake. Dietary biomarkers of specific cereals, different fractions or cereal-containing foods could offer such a possibility. The aim of this review was to summarize the current status on biomarkers of different cereals, fractions, and specific cereal foods.

Subjects and methods

A literature review was conducted and putative biomarkers of different cereals and pseudo-cereals (wheat, oats, rye, barley, rice, and quinoa) as well as for different grain fractions (whole grain, refined grain, bran) and foods were summarized and discussed.

Results

Several putative biomarkers have been suggested for different cereals, due to their unique presence in these grains. Among the biomarkers, odd-numbered alkylresorcinols are the most well-studied and -evaluated biomarkers and reflect whole-grain wheat and rye intake. Even-numbered alkylresorcinols have been suggested to reflect quinoa intake. Recent studies have also highlighted the potential of avenanthramides and avenacosides as specific biomarkers of oat intake, and a set of biomarkers have been suggested to reflect rice bran intake. However, there are yet no specific biomarkers of refined grains. Most biomarker candidates remain to be evaluated in controlled interventions and free-living populations before applied as biomarkers of intake in food and health studies.

Conclusion

Several putative biomarkers of different cereals have been suggested and should be validated in human studies using recently developed food intake biomarker validation criteria.

Contribution of gut microbiota to metabolism of dietary glycine betaine in mice and in vitro colonic fermentation

BACKGROUND

Accumulating evidence is supporting the protective effect of whole grains against several chronic diseases. Simultaneously, our knowledge is increasing on the impact of gut microbiota on our health and on how diet can modify the composition of our bacterial cohabitants. Herein, we studied C57BL/6 J mice fed with diets enriched with rye bran and wheat aleurone, conventional and germ-free C57BL/6NTac mice on a basal diet, and the colonic fermentation of rye bran in an in vitro model of the human gastrointestinal system. We performed 16S rRNA gene sequencing and metabolomics on the study samples to determine the effect of bran-enriched diets on the gut microbial composition and the potential contribution of microbiota to the metabolism of a novel group of betainized compounds.

RESULTS

The bran-enriched study diets elevated the levels of betainized compounds in the colon contents of C57BL/6 J mice. The composition of microbiota changed, and the bran-enriched diets induced an increase in the relative abundance of several bacterial taxa, including Akkermansia, Bifidobacterium, Coriobacteriaceae, Lactobacillus, Parasutterella, and Ruminococcus, many of which are associated with improved health status or the metabolism of plant-based molecules. The levels of betainized compounds in the gut tissues of germ-free mice were significantly lower compared to conventional mice. In the in vitro model of the human gut, the production of betainized compounds was observed throughout the incubation, while the levels of glycine betaine decreased. In cereal samples, only low levels or trace amounts of other betaines than glycine betaine were observed.

CONCLUSIONS

Our findings provide evidence that the bacterial taxa increased in relative abundance by the bran-based diet are also involved in the metabolism of glycine betaine into other betainized compounds, adding another potential compound group acting as a mediator of the synergistic metabolic effect of diet and colonic microbiota.

Whole grain-rich diet reduces body weight and systemic low-grade inflammation without inducing major changes of the gut microbiome: a randomised cross-over trial

OBJECTIVE

To investigate whether a whole grain diet alters the gut microbiome and insulin sensitivity, as well as biomarkers of metabolic health and gut functionality.

DESIGN

60 Danish adults at risk of developing metabolic syndrome were included in a randomised cross-over trial with two 8-week dietary intervention periods comprising whole grain diet and refined grain diet, separated by a washout period of ≥6 weeks. The response to the interventions on the gut microbiome composition and insulin sensitivity as well on measures of glucose and lipid metabolism, gut functionality, inflammatory markers, anthropometry and urine metabolomics were assessed.

RESULTS

50 participants completed both periods with a whole grain intake of 179±50 g/day and 13±10 g/day in the whole grain and refined grain period, respectively. Compliance was confirmed by a difference in plasma alkylresorcinols (p<0.0001). Compared with refined grain, whole grain did not significantly alter glucose homeostasis and did not induce major changes in the faecal microbiome. Also, breath hydrogen levels, plasma short-chain fatty acids, intestinal integrity and intestinal transit time were not affected. The whole grain diet did, however, compared with the refined grain diet, decrease body weight (p<0.0001), serum inflammatory markers, interleukin (IL)-6 (p=0.009) and C-reactive protein (p=0.003). The reduction in body weight was consistent with a reduction in energy intake, and IL-6 reduction was associated with the amount of whole grain consumed, in particular with intake of rye.

CONCLUSION

Compared with refined grain diet, whole grain diet did not alter insulin sensitivity and gut microbiome but reduced body weight and systemic low-grade inflammation.

TRIAL REGISTRATION NUMBER

NCT01731366; Results.

Diets rich in whole grains increase betainized compounds associated with glucose metabolism

Background

Epidemiologic evidence suggests that diets rich in whole grains are associated with a reduced risk of developing chronic diseases and all-cause mortality. However, the molecular mechanisms behind these beneficial metabolic effects are poorly understood.

Objective

Our aim was to investigate novel trimethylated (betainized) compounds from mice and humans, and their association with whole grain-rich diets and insulin resistance and insulin secretion.

Design

Fasting plasma samples were obtained in a mouse (C57BL/6J male) feeding trial and a controlled dietary intervention. The mouse trial involved feeding the mice a rye and wheat bran-enriched feed which was compared with a high-fat diet. In the human trial, participants recruited from Kuopio, Finland (n = 69) and Naples, Italy (n = 54) with characteristics of the metabolic syndrome were randomly assigned to either a whole grain-enriched diet or a control diet for 12 wk. Plasma concentrations of betainized compounds were analyzed with the use of liquid chromatography-tandem mass spectrometry. Insulin resistance and insulin secretion were assessed in an oral-glucose-tolerance test and a meal-glucose-tolerance test.

Results

The betaines that were increased in mouse plasma after bran-enriched feeding were identified de novo via chemical synthesis and liquid chromatography-tandem mass spectrometry, and confirmed to be associated with an increased intake of whole-grain products in humans. In particular, the concentrations of pipecolic acid betaine were increased at the end of the whole-grain intervention in both the Kuopio cohort (P < 0.001) and the Naples cohort (P < 0.05), and these concentrations inversely correlated with the postprandial glucose concentration. Furthermore, the concentration of valine betaine was substantially increased during the intervention in Naples (P < 0.001) with an inverse correlation with the postprandial insulin concentration. In addition, the concentrations of other betaines, e.g., glycine betaine and proline betaine, correlated with glucose and insulin concentrations at the end of the intervention.

Conclusions

Novel betainized compounds in humans are associated with diets rich in whole grains, and they improve insulin resistance and insulin secretion. These results suggest that these novel compounds may contribute to the beneficial effects of whole grain-rich diets. The studies were registered at clinicaltrials.gov as NCT00945854 (Naples) and NCT00573781 (Kuopio).

Identification and heterologous reconstitution of a 5-alk(en)ylresorcinol synthase from endophytic fungus Shiraia sp. Slf14

A new type III polyketide synthase gene (Ssars) was discovered from the genome of Shiraia sp. Slf14, an endophytic fungal strain from Huperzia serrata. The intron-free gene was cloned from the cDNA and ligated to two expression vectors pET28a and YEpADH2p-URA3 for expression in Escherichia coli BL21(DE3) and Saccharomyces cerevisiae BJ5464, respectively. SsARS was efficiently expressed in E. coli BL21(DE3), leading to the synthesis of a series of polyketide products. Six major products were isolated from the engineered E. coli and characterized as 1,3-dihydroxyphenyl-5-undecane, 1,3-dihydroxyphenyl-5-cis-6'-tridecene,1,3-dihydroxyphenyl-5-tridecane, 1,3-dihydroxyphenyl-5-cis-8'-pentadecene, 1,3-dihydroxyphenyl-5-pentadecane, and 1,3-dihydroxyphenyl-5-cis-10'-heptadecene, respectively, based on the spectral data and biosynthetic origin. Expression of SsARS in the yeast also led to the synthesis of the same polyketide products, indicating that this enzyme can be reconstituted in both heterologous hosts. Supplementation of soybean oil into the culture of E. coli BL21(DE3)/SsARS increased the production titers of 1-6 and led to the synthesis of an additional product, which was identified as 5-(8'Z,11'Z-heptadecadienyl) resorcinol. This work thus allowed the identification of SsARS as a 5-alk(en)ylresorcinol synthase with flexible substrate specificity toward endogenous and exogenous fatty acids. Desired resorcinol derivatives may be synthesized by supplying corresponding fatty acids into the culture medium.

Glycaemic, gastrointestinal and appetite responses to breakfast porridges from ancient cereal grains: A MRI pilot study in healthy humans

Cereal grain based porridges are commonly consumed throughout the world. Whilst some data are available for varieties that are popular in the Western world such as oats and rye, other 'ancient' grains used in the East and in Africa such as millets are thought to have beneficial health effects, such as a suppression of post prandial hunger and circulating glucose levels. These grains, a sustainable food source due to their tolerance of extreme weather and growing conditions, are commonly found throughout Asia and Africa. However, knowledge of the physiological responses to these grain varieties is very limited. This study aimed to collect initial pilot data on the physiological and gastrointestinal responses to breakfast porridges made with two millet varieties and oats and rye grains. A total of n=15 completed the oats and rye, n=9 the finger millet n=12 the pearl millet meals. MRI scans were undertaken at baseline, immediately after consumption and then hourly postprandially. Blood glucose was measured at baseline, immediately after consumption and then every 15min until t=80min, then every 20min until t=120min, followed on each occasion by completion of VAS. Seven participants completed the entire protocol and were included in the final analysis. A subgroup analysis with the n=10 paired comparison between the same individuals that completed the oats, rye and pearl millet was also considered. The gastric volume AUC was higher for pearl millet than oats and rye (n=10, p<0.001). The incremental area under the curve (iAUC) for blood glucose was not significantly different between the meals although this showed a trend to be lower for pearl millet. Hunger was lower for pearl millet compared to oats and rye (n=10, p=0.01). There was a significant correlation between total gastric volume AUC and average appetite AUC r=-0.47, p<0.010. Isoenergetic breakfast porridges from 'ancient' varieties of millet grains showed physiological responses that were comparable with those from common Western varieties known to have beneficial health effects. Pearl millet appeared to induce lower postprandial blood glucose response and appetite scores though the differences were not conclusive compared with the other porridges and further work is needed. Improved knowledge of the effects of different cereal grains could help direct dietary advice and ultimately improve health outcomes in the general population worldwide.

Targeted metabolomics reveals differences in the extended postprandial plasma metabolome of healthy subjects after intake of whole-grain rye porridges versus refined wheat bread

SCOPE

We previously found that whole-grain (WG) rye porridges suppressed appetite and improved glucose metabolism. This study aimed to investigate potential plasma metabolites that may be related to differences in those appetite and glucose responses.

METHODS AND RESULTS

Twenty-one health subjects consumed six isocaloric breakfasts in a randomized cross-over study. Plain WG rye porridges (40 and 55 g), rye porridge enriched with different inulin: gluten proportions (9:3 g; 6:6 g; 3:9 g), and a 55 g refined wheat bread (control) were served as part of complete breakfast, followed by a standardized lunch. NMR metabolomics assessed 36 plasma metabolites and short chain fatty acids were measured by GC-MS from baseline up to 8 h. Pre-lunch plasma essential amino acids reflected protein composition and post-lunch plasma short chain fatty acids varied with fiber content in breakfasts. No correlations were observed between measured metabolites and glucose, insulin, or appetite responses.

CONCLUSIONS

Differences in protein and fiber contents in breakfasts altered postprandial plasma amino acids and short chain fatty acids, respectively, but were unrelated to appetite and glucose responses. Further studies are warrant to identify the underlying mechanisms for the beneficial effects on appetite and second meal glucose responses after rye-based foods.

Consumption of whole grains in relation to mortality from all causes, cardiovascular disease, and diabetes: Dose-response meta-analysis of prospective cohort studies

BACKGROUND

To investigate the correlation between consumption of whole grains and the risk of all-cause, cardiovascular disease (CVD), and diabetes-specific mortality according to a dose-response meta-analysis of prospective cohort studies.

METHODS

Observational cohort studies, which reported associations between whole grains and the risk of death outcomes, were identified by searching articles in the MEDLINE, EMBASE, and the reference lists of relevant articles. The search was up to November 30, 2015. Data extraction was performed by 2 independent investigators, and a consensus was reached with involvement of a third.

RESULTS

Ten prospective cohort studies (9 publications) were eligible in this meta-analysis. During follow-up periods ranging from 5.5 to 26 years, there were 92,647 deaths among 782,751 participants. Overall, a diet containing greater amounts of whole grains may be associated with a lower risk of all-cause, CVD-, and coronary heart disease (CHD)-specific mortality. The summary relative risks (RRs) were 0.93 (95% confidence intervals [CIs]: 0.91-0.95; Pheterogeneity < 0.001) for all-cause mortality, 0.95 (95% CIs: 0.92-0.98; Pheterogeneity < 0.001) for CVD-specific mortality, and 0.92 (95% CIs: 0.88-0.97; Pheterogeneity < 0.001) for CHD-specific mortality for an increment of 1 serving (30 g) a day of whole grain intake. The combined estimates were robust across subgroup and sensitivity analyses. Higher consumption of whole grains was not appreciably associated with risk of mortality from stroke and diabetes.

CONCLUSION

Evidence from observational cohort studies indicates inverse associations of intake of whole grains with risk of mortality from all-cause, CVD, and CHD. However, no associations with risk of deaths from stroke and diabetes were observed.

Plasma alkylresorcinols, biomarkers of whole-grain wheat and rye intake, and risk of type 2 diabetes in Scandinavian men and women

BACKGROUND

Studies that use dietary biomarkers to investigate the association between whole-grain intake and the risk of developing type 2 diabetes (T2D) are lacking.

OBJECTIVE

We examined the association between plasma total alkylresorcinols and the alkylresorcinol C17:0-to-C21:0 ratio, biomarkers of whole-grain wheat and rye intake and relative whole-grain rye over whole-grain wheat intake, respectively, and the risk of T2D among Scandinavian men and women.

DESIGN

A nested case-control study was established within the Northern Sweden Health and Disease Study and the Danish Diet, Cancer and Health cohort. Alkylresorcinol concentrations and the ratios of C17:0 to C21:0 were determined in plasma samples from 931 case-control pairs. ORs for T2D were calculated for plasma total alkylresorcinol concentration or C17:0-to-C21:0 ratio in quartiles with the use of conditional logistic regression that was adjusted for potential confounders. Additional analyses with whole-grain wheat and rye intake estimated from food-frequency questionnaires (FFQs) as exposures were also performed.

RESULTS

The plasma total alkylresorcinol concentration was not associated with T2D risk (OR: 1.34; 95% CI: 0.95, 1.88) for the highest compared with the lowest quartiles in multivariable adjusted models. However, the C17:0-to-C21:0 ratio was associated with a lower diabetes risk (OR: 0.54; 95% CI: 0.37, 0.78). Analyses with whole-grain intake estimated from FFQs yielded similar results.

CONCLUSIONS

Total whole-grain wheat and rye intake, reflected by alkylresorcinols in plasma, was not associated with a lower risk of T2D in a population with high whole-grain intake. In contrast, the proportion of whole-grain rye to whole-grain wheat intake, indicated by the plasma C17:0-to-C21:0 ratio, was inversely associated with T2D. This suggests that whole-grain intake dominated by rye may be favorable for T2D prevention.

Whole-grain consumption and the risk of all-cause, CVD and cancer mortality: a meta-analysis of prospective cohort studies

Results of the relationships between dietary whole-grain consumption and the risk of all-cause, CVD and cancer-specific mortality are mixed. We summarised the evidence based on a meta-analysis of prospective cohort studies. Pertinent studies were identified by searching articles in the MEDLINE and EMBASE databases up to 20 January 2016 and by reviewing the reference lists of the retrieved articles. Random-effects models were used to calculate summary relative risks (SRR) and 95 % CI. In all, eleven prospective studies (ten publications) were included in the meta-analysis. There were a total of 816 599 subjects and 89 251 cases of all-cause mortality. On the basis of the highest v. the lowest categories of intake, whole grains may be associated with a lower risk of mortality from all causes (SRR 0·87; 95 % CI 0·84, 0·90), CVD (SRR 0·81; 95 % CI 0·75, 0·89) and all cancers (SRR 0·89; 95 % CI 0·82, 0·96). For each 3 servings/d increase in whole-grain intake, there was a 19 % reduction in the risk of all-cause mortality (SRR 0·81; 95 % CI 0·76, 0·85), a 26 % reduction in CVD mortality (SRR 0·74; 95 % CI 0·66, 0·83) and a 9 % reduction in cancer mortality (SRR 0·91; 95 % CI 0·84, 0·98). The current meta-analysis provides some evidence that high intake of whole grains was inversely associated with the risk of all-cause, CVD and cancer-specific mortality. Further well-designed studies, including clinical trials and in different populations, are required to confirm our findings.

Determination of alkylresorcinols and their metabolites in biological samples by gas chromatography-mass spectrometry

High throughput GC-MS methods for quantification of alkylresorcinols (AR), biomarkers of whole grain wheat and rye intake, in plasma and adipose tissue and their metabolites in urine were developed and optimised. Alkylresorcinols in plasma (200μL) and adipose tissues (10-50mg) were extracted with diethyl ether, whereas main AR metabolites such as DHBA and DHPPA and newly identified metabolites in urine (50μL) were extracted with ethyl acetate after enzymatic deconjugation. All extracts were purified on OASIS-MAX solid phase extraction cartridges. Plasma and adipose tissue sample extracts were then derivatised with trifluoroacetic anhydride and reconstituted in undecane, whereas AR metabolites in urine samples were derivatised with BSTFA+TMCS (99:1, v/v, 100μL). Prepared samples were quantified by GC-MS (EI-SIM). Analysis of all compounds in the different matrices showed good selectivity, sensitivity, linearity, precision (<15% within and between batches), adequate recovery (75-108%), and short total run time (10-12min). The methods developed are applicable to large-scale sample sets such as epidemiological studies.

Whole-grain foods and chronic disease: evidence from epidemiological and intervention studies

Cereal-based foods are key components of the diet and they dominate most food-based dietary recommendations in order to achieve targets for intake of carbohydrate, protein and dietary fibre. Processing (milling) of grains to produce refined grain products removes key nutrients and phytochemicals from the flour and although in some countries nutrients may be replaced with mandatory fortification, overall this refinement reduces their potential nutritional quality. There is increasing evidence from both observational and intervention studies that increased intake of less-refined, whole-grain (WG) foods has positive health benefits. The highest WG consumers are consistently shown to have lower risk of developing CVD, type 2 diabetes and some cancers. WG consumers may also have better digestive health and are likely to have lower BMI and gain less weight over time. The bulk of the evidence for the benefits of WG comes from observational studies, but evidence of benefit in intervention studies and potential mechanisms of action is increasing. Overall this evidence supports the promotion of WG foods over refined grain foods in the diet, but this would require adoption of standard definitions of 'whole grain' and 'whole-grain foods' which will enable innovation by food manufacturers, provide clarity for the consumer and encourage the implementation of food-based dietary recommendations and public health strategies.

Ancient Wheat Diet Delays Diabetes Development in a Type 2 Diabetes Animal Model

AIM

The main objective was to investigate the physiological effects of ancient wheat whole grain flour diets on the development and progression of type 2 diabetes in Zucker diabetic fatty (ZDF) rats, and specifically to look at the acute glycemic responses.

METHODS

An intervention study was conducted, involving 40 ZDF rats consuming one of 5 different diets (emmer, einkorn, spelt, rye and refined wheat) for 9 weeks. Refined wheat flour and whole grain rye flour were included as negative and positive controls, respectively.

RESULTS

After 9 weeks of intervention, a downregulation of the hepatic genes PPAR-α, GLUT2, and SREBP-1c was observed in the emmer group compared to the control wheat group. Likewise, expression of hepatic SREBP-2 was lower for emmer, einkorn, and rye compared with the control group. Furthermore, spelt and rye induced a low acute glycemic response. The wheat group had higher HDL- and total cholesterol levels.

CONCLUSIONS

Ancient wheat diets caused a downregulation of key regulatory genes involved in glucose and fat metabolism, equivalent to a prevention or delay of diabetes development. Spelt and rye induced a low acute glycemic response compared to wheat.