High Amylose Wheat Bread at Breakfast Increases Plasma Propionate Concentrations and Reduces the Postprandial Insulin Response to the Following Meal in Overweight Adults.

BACKGROUND: High amylose starchy foods modulate the postprandial metabolic response in humans. However, the mechanisms of their metabolic benefits and their impact on the subsequent meal have not been fully elucidated. OBJECTIVE: We aimed to evaluate whether glucose and insulin responses to a standard lunch are influenced by the consumption of amylose-rich bread at breakfast in overweight adults and whether changes in plasma short chain fatty acids (SCFAs) concentrations contribute to their metabolic effects. METHODS: Using a randomized crossover design, 11 men and 9 women, BMI 30 ± 3 kg/m2, 48 ± 19 y, consumed at breakfast 2 breads made with high amylose flour (HAF): 85%-HAF (180 g) and 75%-HAF (170 g), and control bread (120 g) containing 100% conventional flour. Plasma samples were collected at fasting, 4 h after breakfast, and 2 h after a standard lunch to measure glucose, insulin, and SCFA concentrations. ANOVA posthoc analyses were used for comparisons. RESULTS: Postprandial plasma glucose responses were 27% and 39% lower after breakfasts with 85%- and 70%-HAF breads than control bread (P = 0.026 and P = 0.003, respectively), with no difference after lunch. Insulin responses were not different between the 3 breakfasts, whereas there was a 28% lower response after the lunch following breakfast with 85%-HAF bread than the control (P = 0.049). Propionate concentrations increased from fasting by 9% and 12% 6 h after breakfasts with 85%- and 70%-HAF breads and decreased by 11% with control bread (P < 0.05). At 6 h after breakfast with 70%-HAF bread, plasma propionate and insulin were inversely correlated (r = -0.566; P = 0.044). CONCLUSIONS: Amylose-rich bread reduces the postprandial glucose response after breakfast and insulin concentrations after the subsequent lunch in overweight adults. This second meal effect may be mediated by the elevation of plasma propionate due to intestinal fermentation of resistant starch. High amylose products could be a promising tool in a dietary prevention strategy for type 2 diabetes. THIS TRIAL WAS REGISTERED AT CLINICAL TRIAL REGISTRY AS: NCT03899974 (https://www. CLINICALTRIALS: gov/ct2/show/NCT03899974).

A wheat aleurone-rich diet improves oxidative stress but does not influence glucose metabolism in overweight/obese individuals: Results from a randomized controlled trial.

BACKGROUND AND AIMS: Aleurone is the innermost layer of wheat bran, rich in fiber, minerals, vitamins, phenolic compounds, and betaine. The metabolic effects of aleurone rich foods are still unknown. Our aim was to investigate the effects of consuming a Wheat Aleurone rich diet vs. a Refined Wheat diet for 8 weeks on fasting and postprandial glycemic and lipid metabolism, inflammation, and oxidative stress in overweight/obese individuals. METHODS AND RESULTS: According to a randomized cross-over study design, 23 overweight/obese individuals, age 56 ± 9 years (M±SD), were assigned to two isoenergetic diet - Wheat Aleurone and Refined Wheat diets - for 8 weeks. The diets were similar for macronutrient composition but different for the aleurone content (40-50 g/day in the Wheat Aleurone diet). After each diet, fasting and postprandial plasma metabolic profile, ferulic acid metabolites and 8-isoprostane concentrations in 24-h urine samples were evaluated. Compared with the Refined Wheat Diet, the Wheat Aleurone Diet increased fasting plasma concentrations of betaine by 15% (p = 0.042) and decreased the excretion of 8-isoprostane by 33% (p = 0.035). Conversely, it did not affect the fasting and postprandial glucose, insulin and triglyceride responses, homocysteine, and C-Reactive Protein concentrations, nor excretion of phenolic metabolites. CONCLUSION: An 8-week Wheat Aleurone Diet improves the oxidative stress and increases plasma betaine levels in overweight/obese individuals with an increased cardiometabolic risk. However, further studies with longer duration and larger sample size are needed to evaluate the benefits of aleurone-rich foods on glucose and lipid metabolism in individuals with more severe metabolic abnormalities. CLINICAL TRIAL REGISTRY NUMBER: NCT02150356, (https://clinicaltrials.gov).

Putative metabolites involved in the beneficial effects of wholegrain cereal: Nontargeted metabolite profiling approach.

BACKGROUND AND AIMS: Wholegrain cereals have been implicated in the reduction of lifestyle-related chronic diseases risk including cardiovascular diseases and type 2 diabetes. Molecular mechanisms responsible for the beneficial health effects are not entirely understood. The aims of this study were 1) to identify new potential plasma biomarker candidate metabolites of wholegrain cereal foods intake and 2) to examine whether some putative metabolites associated with wholegrain foods intake may play a role in the improvement of cardiometabolic risk factors. METHODS AND RESULTS: Analysis have been conducted in 54 individuals with metabolic syndrome of both genders, age 40-65 years, randomly assigned to 2 dietary interventions lasting 12-week: 1) wholegrain enriched diet (n = 28), and 2) refined-wheat cereals diet (control diet) (n = 26). Nontargeted metabolite profiling analysis was performed on fasting plasma samples collected at baseline and at the end of the experimental diets. Our data show that, at the end of the intervention, a higher intake of wholegrain (tertile 3) was significantly associated with a marked increase in several lipid compounds, as PC (20:4/16:1), LPC (20:4), LPC (22:6), LPC (18:3), LPC (22:5), and a phenolic compound (P < .05 for all). In the wholegrain group, higher concentrations of these metabolites (tertile 3 vs tertile 1 of each metabolite) were significantly associated with lower postprandial insulin and triglyceride responses (P < .05) by 29% and 37%, respectively. CONCLUSION: These observations suggest a possible role of lipid and polyphenol metabolites in the postprandial metabolic benefits of wholegrains in subjects at high risk of cardiovascular disease. In addition, they provide insight into the role of these metabolites as potential candidate biomarkers of wholegrain foods. The study was registered on ClinicalTrials.gov (identifier: NCT00945854).

The Mediterranean diet from past to future: Key concepts from the second "Ancel Keys" International Seminar.

The year 2020 celebrated the tenth anniversary of the recognition of the Mediterranean Diet as Intangible Cultural Heritage of Humanity by the UNESCO Intergovernmental Committee. This event represented a milestone in the history of nutrition, as the Mediterranean diet was the first traditional food practice to receive such award. Since then, a lot has been discussed not only on the beneficial aspects of the Mediterranean diet, but also on its complex role as a lifestyle model that includes a set of skills, knowledge and intercultural dialogue. This process ended up with the recognition in 2019 of Mediterranean diet as a possibly universal model of healthy diet from the EAT-Lancet Commission. These concepts were widely debated at the 2019 "Ancel Keys" International Seminar, held in Ascea (Italy) (for more information see: www.mediterraneandietseminar.org) with the aim to stimulate interest and awareness of a young group of participants on the current problems inherent to the effective implementation of the Mediterranean diet. The present article collects the contributions of several lecturers at the Seminar on key issues such as methodological and experimental approach, sustainability, molecular aspects in disease prevention, future exploitation, without neglecting a historical view of the Seven Countries Study. From the Seminar conclusions emerged a still vibrant and modern role of Mediterranean diet. The years to come will see national and international efforts to reduce the barriers that limit adherence to Mediterranean diet in order to plan for multi-factorial and targeted interventions that would guide our populations to a sustainable healthy living.

An Oily Fish Diet Improves Subclinical Inflammation in People at High Cardiovascular Risk: A Randomized Controlled Study.

Interest has arisen on the anti-inflammatory action of dietary components, including long-chain n-3 fatty acids (LCn3) and polyphenols (PP). The aim of this study was to evaluate the effects of diets rich in PP and oily fish (high-LCn3 diets) on markers of subclinical inflammation and growth factors in people at high cardiometabolic risk. Individuals with high waist circumference and one more component of metabolic syndrome were randomized to one of the following isoenergetic diets: low LCn3&PP, high LCn3, high PP, high LCn3&PP. Before and after 8 weeks, fasting and postprandial plasma concentrations of hs-CRP and fasting serum concentrations of IL-1, IL-4, IL-6, IL-10, IL-17, INF-, TNF-, FGF, VEGF, PDGF-, G-CSF, and GM-CSF were determined. An oily fish diet reduced fasting plasma hs-CRP (1.28 ± 12.0, -12.5 ± 6.9, 22.5 ± 33.6, -12.2 ± 11.9; 8-week percent change, Mean ± SEM; low LCn3&PP, high LCn3, high PP, high LCn3&PP group, respectively), postprandial 6h-AUC hs-CRP (4.6 ± 16.3, -18.2 ± 7.2, 26.9 ± 35.1, -11.5 ± 11.8, 8-week percent change) and fasting IL-6 (20.8 ± 18.7, -2.44 ± 12.4, 28.1 ± 17.4, -9.6 ± 10.2), IL-17 (2.40 ± 4.9, -13.3 ± 4.9, 3.8 ± 4.43, -11.5 ± 4.7), and VEGF (-5.7 ± 5.8, -5.6 ± 7.5, 3.5 ± 5.8, -11.1 ± 5.5) (8-week percent change; p < 0.05 for LCn3 effect for all; no significant effect for PP; 2-factor ANOVA). An oily fish diet improved subclinical inflammation, while no significant effect was observed for dietary polyphenols.

Mediterranean diet intervention in overweight and obese subjects lowers plasma cholesterol and causes changes in the gut microbiome and metabolome independently of energy intake.

OBJECTIVES: This study aimed to explore the effects of an isocaloric Mediterranean diet (MD) intervention on metabolic health, gut microbiome and systemic metabolome in subjects with lifestyle risk factors for metabolic disease. DESIGN: Eighty-two healthy overweight and obese subjects with a habitually low intake of fruit and vegetables and a sedentary lifestyle participated in a parallel 8-week randomised controlled trial. Forty-three participants consumed an MD tailored to their habitual energy intakes (MedD), and 39 maintained their regular diets (ConD). Dietary adherence, metabolic parameters, gut microbiome and systemic metabolome were monitored over the study period. RESULTS: Increased MD adherence in the MedD group successfully reprogrammed subjects' intake of fibre and animal proteins. Compliance was confirmed by lowered levels of carnitine in plasma and urine. Significant reductions in plasma cholesterol (primary outcome) and faecal bile acids occurred in the MedD compared with the ConD group. Shotgun metagenomics showed gut microbiome changes that reflected individual MD adherence and increase in gene richness in participants who reduced systemic inflammation over the intervention. The MD intervention led to increased levels of the fibre-degrading Faecalibacterium prausnitzii and of genes for microbial carbohydrate degradation linked to butyrate metabolism. The dietary changes in the MedD group led to increased urinary urolithins, faecal bile acid degradation and insulin sensitivity that co-varied with specific microbial taxa. CONCLUSION: Switching subjects to an MD while maintaining their energy intake reduced their blood cholesterol and caused multiple changes in their microbiome and metabolome that are relevant in future strategies for the improvement of metabolic health.

Effects of polyphenols on cardio-metabolic risk factors and risk of type 2 diabetes. A joint position statement of the Diabetes and Nutrition Study Group of the Italian Society of Diabetology (SID), the Italian Association of Dietetics and Clinical Nutrition (ADI) and the Italian Association of Medical Diabetologists (AMD).

AIM: A large body of evidence supports a role of polyphenols in the prevention of chronic diseases, i.e. type 2 diabetes (DMT2), cardiovascular diseases and some types of cancer. In the present manuscript, the effect of polyphenol/phenolic compounds on the main cardio-metabolic risk factors (body weight, blood pressure, blood glucose concentrations, plasma lipids, inflammation and oxidative stress) in humans will be discussed. DATA SYNTHESIS: Epidemiological evidence supports the beneficial effects of polyphenol-rich diets in the prevention of T2D risk. However, the available evidence from randomized controlled clinical trials did not allow the identification of specific phenolic compounds or polyphenol-rich foods that effectively improve cardio-metabolic risk factors. The most promising results in terms of the management of cardio-metabolic risk factors derive from RCTs based on a long-term intake of polyphenol-rich foods and beverages. Therefore, future studies should focus on a diet containing different classes of polyphenols rather than a specific food or phenolic compound. The hypothesis is that a polyphenol-rich diet may have a pleiotropic effect on cardiometabolic risk factors thanks to the specific action of different polyphenol subclasses. CONCLUSION: The lack of conclusive evidence on the effectiveness of polyphenols in the management of cardio-metabolic risk factors does not allow recommendation of their use as supplements to reduce T2D and CVD risk. However, the daily consumption of naturally polyphenol-rich foods and beverages might be advised according to the current nutritional dietary recommendation.

Nutritional factors influencing plasma adiponectin levels: results from a randomised controlled study with whole-grain cereals.

Data from intervention studies about the effects of a high intake of whole-grain cereals on adiponectin expression are still inconclusive. We evaluated the effects of whole-grain or refined cereals on fasting and postprandial serum adiponectin in people at high cardiovascular risk. According to a randomised controlled parallel group design, participants with metabolic syndrome were assigned to an isoenergetic diet based on either whole-grain cereal (WGC) or refined cereal (RC) products for 12-weeks. Anthropometric and biochemical measures were taken. Compared to baseline, fasting and postprandial serum adiponectin levels increased after both RC and WGC. In the WGC and RC groups combined, adiponectin concentrations significantly increased after 12-week intervention, and are directly associated with plasma SCFAs and acetate. Only increasing whole-grain cereals may not influence adiponectin levels, which could be modified by a fibre rich, low-fat, low-glycemic index diet, possibly through changes in gut microbiota, as suggested by the relation with SCFAs.Clinical Trials number: NCT00945854.

Cow's Milk Consumption and Health: A Health Professional's Guide.

The most recent scientific evidence supports the consumption of cow's milk and dairy products as part of a balanced diet. However, these days, the public and practicing physicans are exposed to a stream of inconsistent (and often misleading) information regarding the relationship between cow's milk intake and health in the lay press and in the media. The purpose of this article, in this context, is to facilitate doctor-patient communication on this topic, providing physicians with a series of structured answers to frequently asked patient questions. The answers range from milk and milk-derived products' nutritional function across the life span, to their relationship with diseases such as osteoporosis and cancer, to lactose intolerance and milk allergy, and have been prepared by a panel of experts from the Italian medical and nutritional scientific community. When consumed according to appropriate national guidelines, milk and its derivatives contribute essential micro- and macronutrients to the diet, especially in infancy and childhood where bone mass growth is in a critical phase. Furthermore, preliminary evidence suggests potentially protective effects of milk against overweight, obesity, diabetes, and cardiovascular disease, while no clear data suggest a significant association between milk intake and cancer. Overall, current scientific literature suggests that an appropriate consumption of milk and its derivatives, according to available nutritional guidelines, may be beneficial across all age groups, with the exception of specific medical conditions such as lactose intolerance or milk protein allergy. Key teaching points: Milk and its derivatives contribute essential micro and macronutrients to the diet, when consumed according to appropriate national guidelines, especially in infancy and childhood where bone mass growth is in a critical phase. Preliminary evidence suggests potentially protective effects of milk against overweight, obesity, diabetes and cardiovascular disease No clear data are available about the association between milk intake and cancer. Current scientific literature suggests that an appropriate consumption of milk and its derivatives may be beneficial at all ages, with the exception of specific medical conditions such as lactose intolerance or milk protein allergy.

Adherence to the traditional Mediterranean diet in a population of South of Italy: factors involved and proposal of an educational field-based survey tool.

We developed and validated a tool assessing the adherence to the Mediterranean diet based on current nutritional recommendations for health promotion (MEDI-Quest). Four-hundred-and-eleven clinically healthy subjects completed both the MEDI-Quest-score and the validated MedDietScore (MDS). A good accordance between MEDI-Quest and MDS was observed (R = 0.638), as well as for the percentage of individuals having similar scores with both methods for each food group. Regarding socio-cultural-factors, higher adherence was observed in people with older-age (OR = 1.030, p < .0001), more qualifier-employment (OR = 1.136, p < .005), higher-income (OR = 1.925, p < .0001), interest in reading-food-labels (OR = 2.057, p < .0001), and having frequent physical activity (OR = 1.608, p < .05). In conclusion, our findings show that (1) the MEDI-Quest score well correlate with MDS, and (2) the adherence to the Mediterranean diet is not particularly high due to less cultural roots. It could be necessary to improve people's knowledge about food and nutrition, taking into consideration believes embedded in their family, tradition and religion.

Bioavailability and pharmacokinetic profile of grape pomace phenolic compounds in humans.

Grape pomace, the major byproduct of the wine and juice industry, is a relevant source of bioactive phenolic compounds. However, polyphenol bioavailability in humans is not well understood, and the inter-individual variability in the production of phenolic metabolites has not been comprehensively assessed to date. The pharmacokinetic and excretive profiles of phenolic metabolites after the acute administration of a drink made from red grape pomace was here investigated in ten volunteers. A total of 35 and 28 phenolic metabolites were quantified in urine and plasma, respectively. The main circulating metabolites included phenyl-γ-valerolactones, hydroxybenzoic acids, simple phenols, hydroxyphenylpropionic acids, hydroxycinnamates, and (epi)catechin phase II conjugates. A high inter-individual variability was shown both in urine and plasma samples, and different patterns of circulating metabolites were unravelled by applying unsupervised multivariate analysis. Besides the huge variability in the production of microbial metabolites of colonic origin, an important variability was observed due to phase II conjugates. These results are of interest to further understand the potential health benefits of phenolic metabolites on individual basis.

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.

A nutritional intervention programme at a worksite canteen to promote a healthful lifestyle inspired by the traditional Mediterranean diet.

This study investigates the effectiveness and long-term impact on the composition of the habitual diet of a nutritional intervention programme - undertaken through panels, totems, and table mats or handout leaflets - based on the promotion at a worksite canteen of healthy food-choices resembling the traditional Mediterranean diet. A significantly higher choice of dishes based on wholegrain cereals, legumes, white meat and fish, and a lower choice of dishes based on refined cereals, red and processed meat, eggs and cheese was observed at the end of the intervention and after six months and three years of follow-ups. A significantly better adherence to the nutritional recommendations for saturated-fat, cholesterol, sugars and fibre was observed. This study reveals that a nutritional intervention programme promoting the traditional Mediterranean diet and utilising a minimally intensive approach is feasible and effective to modify in a beneficial way the dietary habits of a working population and keep these changes in the long-term.

Palm oil and human health. Meeting report of NFI: Nutrition Foundation of Italy symposium.

The use of palm oil by the food industry is increasingly criticized, especially in Italy, for its purported negative effects on human health and environment. This paper summarizes the conclusions of a Symposium on this topic, gathered by the Nutrition Foundation of Italy, among experts representing a number of Italian Medical and Nutritional Scientific Societies. Toxicological and environmental issues were not considered. Participants agreed that: no evidence does exist on the specific health effects of palm oil consumption as compared to other saturated fatty acids-rich fats; the stereospecific distribution of saturated fatty acids in the triacylglycerol molecule of palm oil limits their absorption rate and metabolic effects; in agreement with International guidelines, saturated fatty acids intake should be kept <10% of total energy, within a balanced diet; within these limits, no effect of palm oil consumption on human health (and specifically on CVD or cancer risk) can be foreseen.

Visceral adiposity and subclinical atherosclerosis in healthy young men.

BACKGROUND: Atherosclerosis begins in childhood and develops silently for decades before clinical events such as myocardial infarction or stroke occur. Only few studies have evaluated the relationship between CVD risk factors and carotid artery Intimal Media Thickness (IMT) in young asymptomatic people. AIM: The aim of this study is to investigate risk factors for cardiovascular disease associated with higher Carotid Intimal Media Thickness (IMT) in healthy young subjects. METHODS: A cohort of 106 healthy young men, mean age 21 ± 2 years (mean ± SD), BMI 24.4 ± 2.8 (kg/m(2)), on military duty, participated in this cross-sectional study. Waist circumference, carotid intima-media thickness (IMT), blood pressure, and plasma concentrations of relevant metabolic parameters were measured at fasting. Smoking and habitual dietary patterns were evaluated by a semiquantitative questionnaire. RESULTS: The population was divided into two groups on the basis of IMT values: the lowest three quartiles versus the highest quartile (cut-off value = 0.7 mm). BMI, waist circumference, systolic (SBP), and diastolic (DBP) blood pressure were significantly higher in the group with higher IMT (p = 0.02). All other variables, including dietary parameters and smoking, were similar in the two groups. Data analysis showed that IMT values correlated positively with SBP (r = 0.22; p = 0.025), DBP (r = 0.27; p = 0.005), waist circumference (r = 0.29; p = 0.002), and fat mass (r = 0.24; p = 0.01), and negatively with kcal/kg of body weight (r = -0.220.22; p = 0.022) - an indirect marker of physical activity. Based on multiple regression analysis, waist circumference and DBP were the only variables independently associated with IMT (p = 0.029). CONCLUSIONS: In a non-selected sample of healthy young adult males, a larger waist circumference and a higher diastolic blood pressure - albeit within normal values - are the only parameters independently associated with higher IMT.

Effects on cardiovascular risk factors of a low- vs high-glycemic index Mediterranean diet in high cardiometabolic risk individuals: the MEDGI-Carb study.

BACKGROUND: The role of dietary Glycemic Index (GI), independently of fiber intake, in modulating cardiovascular disease (CVD) risk among non-diabetic individuals has not been fully elucidated. OBJECTIVE: To evaluate the effects of a low- versus a high-GI diet, based on a Mediterranean dietary pattern, on cardiometabolic risk factors in individuals at high CVD risk, participating in the MEDGI-Carb intervention study. SUBJECTS AND METHODS: 160 individuals, aged 30-69 years, BMI 25-37 kg/m2, with a waist circumference >102 cm (males) or >88 cm (females) and one feature of the metabolic syndrome, participated in a multi-national (Italy, Sweden, USA) randomized controlled parallel group trial. Participants were assigned to a low GI (< 55) or high-GI MedDiet ( > 70) for 12 weeks. The diets were isoenergetic and similar for available carbohydrate (270 g/d) and fiber (35 g/d) content. Fasting metabolic parameters were evaluated in the whole cohort, while an 8-h triglyceride profile (after standard breakfast and lunch) was evaluated only in the Italian cohort. RESULTS: Blood pressure and most fasting metabolic parameters improved at the end of the dietary intervention (time effect, p < 0.05 for all); however, no differences were observed between the low- and the high-GI MedDiet groups (time x group effect; p > 0.05 for all). Conversely, the low-GI diet, compared with high-GI diet, significantly reduced the 8-h triglyceride profile (p < 0.017, time*group effect) that was measured only in the Italian cohort. However, it induced a reduction of plasma triglycerides after lunch (tAUC) that was of only borderline statistically significance (p = 0.065). CONCLUSIONS: Consuming a low-GI in comparison with a high-GI MedDiet does not differentially affect the major cardiometabolic risk factors at fasting in individuals at increased cardiometabolic risk. Conversely, it could reduce postprandial plasma triglycerides. CLINICAL TRIAL REGISTRY NUMBER: NCT03410719, ( https://clinicaltrials.gov ).

Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies.

Evidence of associations between ultra-processed foods (UPF) and increased risk of cardiovascular disease is emerging, but it is unclear how much this is influenced by the methodology used to assess the UPF intake or by the level of consumption. We conducted a meta-analysis to evaluate 1) the association between UPF consumption and risk of diabetes, hypertension, dyslipidemia, and obesity, using prospective cohort studies; 2) the differential associations depending on the methodology used to assess UPF intake and the level of UPF consumption and 3) the quality of evidence using the NutriGrade scoring system. A systematic literature search was conducted in PubMed/MEDLINE, ISI Web of Science, and Scopus through 1 April, 2023, on studies conducted in humans providing data for the highest compared with the lowest UPF consumption categories. Summary relative ratios (RRs) and 95% confidence intervals (95% CI) were estimated using a random-effects model. Out of 4522 articles retrieved from the literature search, 25 reports met the criteria for inclusion in the meta-analysis, 7 for diabetes, 5 for hypertension, 3 for dyslipidemia, and 13 for obesity. A consistently positive association between high UPF intake and increased risk of developing diabetes (37%), hypertension (32%), hypertriglyceridemia (47%), low HDL cholesterol concentration (43%), and obesity (32%) was observed, even if the quality of evidence was not satisfying. However, these risks varied significantly depending on the methodology used to assess UPF consumption, with a difference of more than 50% between the methods. Based on the level of intake, we did not observe significant differences in the results. These findings show that UPF consumption is associated with higher risk of diabetes, hypertension, dyslipidemia, and obesity, but the level of risk consistently changes depending on the methodology used to assess UPF intake. Therefore, caution should be used when interpreting and extrapolating the results.

The effects of Mediterranean diets with low or high glycemic index on plasma glucose and insulin profiles are different in adult men and women: Data from MEDGI-Carb randomized clinical trial.

BACKGROUND & AIMS: Recent evidence suggests that the ability to regulate glucose and insulin homeostasis is different in men and women. Against this background, it has been hypothesized that the impact on daily plasma glucose and insulin profiles of the glycemic index (GI) of the habitual diet may differ according to sex. The aim of this study is to evaluate whether 8-h average plasma glucose and insulin profiles during a low- or a high-GI diet in individuals at high risk of developing type 2 diabetes are influenced by sex. METHODS: We conducted a randomized, controlled, parallel group dietary intervention, comparing high-versus low-GI diets in a multi-national (Italy, Sweden, and the United States) sample of 156 adults at risk for type 2 diabetes. For 12 weeks, 82 vs 74 participants consumed either a low-GI or high-GI Mediterranean diet, respectively. The two experimental diets contained the same quantity of available carbohydrate (270 g/d) and fiber (35 g/d) and the same foods and beverages, except for the major sources of starch that was specific to the low-GI and high-GI groups (pasta, brown rice, flatbread, all bran, and wheat bread plus rye and seeds, vs jasmine rice, potato, couscous, wholegrain bread, and rusks). At baseline and after the intervention plasma glucose and insulin profiles were evaluated for 8 h in the two intervention groups - separately for men and women - with both breakfast and lunch resembling food choices of the assigned diet. RESULTS: One hundred fifty-six adults (82 women, 74 men) with at least two traits of the metabolic syndrome completed the intervention. In women, the high-GI induced significantly higher (23%, p < 0.05) 8-h average plasma glucose concentrations in comparison to the low-GI diet already on the first day of the intervention; the difference increased up to 37% (p < 0.05) after 12 weeks of diet. Conversely, there were no significant differences between the two diets in men. These results were confirmed by the two-way analysis of variance showing a statistically significant interaction between the effects of sex and diet on the glucose profile after breakfast and lunch (F = 7.887, p = 0.006). CONCLUSION: The results of our intervention show that women, compared to men, are more sensitive to the metabolic effects of the dietary GI. This has a strong clinical and scientific relevance and, if confirmed in further studies, it might have important implications for dietary strategies for diabetes and cardiovascular disease prevention in the context of personalized nutrition. REGISTRATION NUMBER OF CLINICAL TRIAL: Clinicaltrials.gov n. NCT03410719.

Differential Responders to a Mixed Meal Tolerance Test Associated with Type 2 Diabetes Risk Factors and Gut Microbiota-Data from the MEDGI-Carb Randomized Controlled Trial.

The global prevalence of type 2 diabetes mellitus (T2DM) has surged in recent decades, and the identification of differential glycemic responders can aid tailored treatment for the prevention of prediabetes and T2DM. A mixed meal tolerance test (MMTT) based on regular foods offers the potential to uncover differential responders in dynamical postprandial events. We aimed to fit a simple mathematical model on dynamic postprandial glucose data from repeated MMTTs among participants with elevated T2DM risk to identify response clusters and investigate their association with T2DM risk factors and gut microbiota. Data were used from a 12-week multi-center dietary intervention trial involving high-risk T2DM adults, comparing high- versus low-glycemic index foods within a Mediterranean diet context (MEDGICarb). Model-based analysis of MMTTs from 155 participants (81 females and 74 males) revealed two distinct plasma glucose response clusters that were associated with baseline gut microbiota. Cluster A, inversely associated with HbA1c and waist circumference and directly with insulin sensitivity, exhibited a contrasting profile to cluster B. Findings imply that a standardized breakfast MMTT using regular foods could effectively distinguish non-diabetic individuals at varying risk levels for T2DM using a simple mechanistic model.

Predominant role of obesity/insulin resistance in oxidative stress development.

BACKGROUND: Hyperlipidaemia, hyperglycaemia and hyperinsulinaemia, hallmarks of the postprandial state, have been also associated with increased oxidative stress and lipoprotein oxidation contributing to vascular injury and atherosclerosis. However, the specific links among metabolic disorders, postprandial state, insulin resistance and oxidative stress are still to be clarified. This study aimed at investigating the individual role played by obesity, insulin resistance and type 2 diabetes in the occurrence of fasting and postprandial oxidative stress. DESIGN: Biomarkers of oxidative stress [F2-isoprostanes and circulating oxidized low-density lipoproteins (LDL)], LDL oxidability (conjugated diene kinetic, thiobarbituric acid reactive substances (TBARs) formation and electronegativity increase) and antioxidant vitamins (ß-carotene, α-tocopherol and retinol) were evaluated at fasting and 6 h after a standard fat-rich meal in 10 obese diabetic (ObD), 11 obese and 11 normal-weight control men. Insulin sensitivity was evaluated by euglycaemic hyperinsulinaemic clamp. RESULTS: ObD and obese subjects, characterized by a similar level of adiposity and insulin resistance, showed higher urinary F2-isoprostanes and circulating oxidized LDL, an increased susceptibility to oxidation of plasma LDL (lower lag phase, higher TBARs formation, and higher relative electrophoretic mobility), and lower plasma content of ß-carotene and retinol than control subjects, both at fasting and after the test meal. CONCLUSIONS: Obesity and insulin resistance, more than type 2 diabetes, play the most relevant role in oxidative stress development. The correction of obesity and insulin resistance might be a useful strategy in counteracting systemic oxidative stress.