Dietary glycemic index, glycemic load, fiber, simple sugars, and insulin resistance: the Inter99 study

Does a Ketogenic Diet Have a Place Within Diabetes Clinical Practice? Review of Current Evidence and Controversies

Carbohydrate restriction has gained increasing popularity as an adjunctive nutritional therapy for diabetes management. However, controversy remains regarding the long-term suitability, safety, efficacy and potential superiority of a very low carbohydrate, ketogenic diet compared to current recommended nutritional approaches for diabetes management. Recommendations with respect to a ketogenic diet in clinical practice are often hindered by the lack of established definition, which prevents its capacity to be most appropriately prescribed as a therapeutic option for diabetes. Furthermore, with conflicted evidence, this has led to uncertainty amongst clinicians on how best to support and advise their patients. This review will explore whether a ketogenic diet has a place within clinical practice by reviewing current evidence and controversies.

Effect of weight change on the association between overall and source of carbohydrate intake and risk of metabolic syndrome: Tehran lipid and glucose study

BACKGROUND

In this prospective cohort study, we aimed to evaluate the association between dietary carbohydrates, whole grains, refined grains, and simple sugar with the risk of metabolic syndrome (MetS) and assess the effect of weight change on these associations.

METHODS

This study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS). We included 1915 healthy participants with complete demographic, anthropometric and dietary measurements, among whom 591 developed MetS during 8.9 years of follow-up. Intake of dietary carbohydrates, whole grains, refined grains, and simple sugar was assessed with a validated semi-quantitative food frequency questionnaire. Multivariable adjusted Cox regression was used to estimate hazard ratios (HRs) for MetS events across tertiles of dietary variables. Using joint classification, the effect of weight change on the association between dietary variables and risk of MetS was assessed by Cox regression.

RESULTS

Carbohydrate intake was not associated with the risk of MetS in multivariable-adjusted models. Whole grains intake was inversely associated with the risk of MetS (HR: 0.78, CI: 0.63-0.98), while this association disappeared after adjustment for weight change. The risk of MetS increased by 11% (1.11, 1.09-1.14) for each 3% energy increment from simple sugar, and by 5% (1.05, 1.03-1.08) for each 1 serving/day increment in refined grains. Consumption of refined grains increased the risk of MetS; an effect modification of this association was found by weight change. Among subjects with weight loss, intake of refined grains < median intake decreased the risk of MetS (0.59, 0.41-0.87). However, consumption of refined grains ≥ median intake increased the risk of MetS in individuals with weight gain (1.47, 1.08-2.01). Simple sugar was positively associated with an increased risk of MetS, after adjustment for weight change (3.00, 2.37-3.82). In joint classification, intake of simple sugar greater than median intake increased the risk of MetS, independent of weight change.

CONCLUSION

Our findings suggest an effect modification by weight change on the association between carbohydrates, and refined grains intake and the risk of MetS. Weight loss along with lower consumption of carbohydrates, and refined grains reduced the risk of MetS. However, simple sugar intake, regardless of weight change, was associated with an increased risk of MetS.

Dietary acid load, alternative healthy eating index score, and bacterial vaginosis: is there any association? A case-control study

Background:

Changing the dietary pattern may be an alternative treatment for bacterial vaginosis, the prevalent vaginal infection in women.

Methods:

One hundred and forty-three bacterial vaginosis-affected women diagnosed by Amsel criteria and 151 healthy controls aged 18 to 45 entered the current case-control research. To calculate the alternative healthy eating index and dietary acid load score, food consumption was recorded with an accurate and precise food frequency questionnaire. The dietary acid load was measured by potential renal acid load (PRAL) and net endogenous acid production (NEAP) indices. Using logistic regression models, the association between the alternative healthy eating index and dietary acid load score with bacterial vaginosis was investigated.

Results:

The last tertile of the alternative healthy eating index had a 75% decreased odds of experiencing bacterial vaginosis in the adjusted model (adjusted odds ratio (aOR) = 0.25, 95% confidence interval (CI) = 0.12–0.53, P for trend = 0.001). Besides, vegetables (aOR = 0.34, 95% CI = 0.17–0.69, P for trend = 0.003), nuts and legumes (aOR = 0.44, 95% CI = 0.23–0.87, P for trend = 0.028), and meats (aOR = 0.31, 95% CI = 0.16–0.60, P for trend = 0.001) intake was linked to a decreased bacterial vaginosis odds. However, sugar-sweetened beverages and fruit juice (aOR = 3.47, 95% CI = 1.68–7.17, P for trend < 0.001), trans fatty acids (aOR = 2.29, 95% CI = 1.18–4.43, P for trend = 0.005), and sodium (aOR = 3.44, 95% CI = 1.67–7.06, P for trend = 0.002) intake were directly associated with bacterial vaginosis odds. There was no evidence of a link between dietary acid load and bacterial vaginosis.

Conclusion:

According to the present study’s findings, there is no correlation between dietary acid load and the likelihood of developing bacterial vaginosis. However, following a plant-based dietary pattern based on the healthy eating index may lead to a lower odds of bacterial vaginosis.

Is there any association between adherence to the Mediterranean Diet and Dietary Total Antioxidant Capacity with Bacterial Vaginosis? Results from a Case-Control study

Background

Bacterial vaginosis, BV, is a common inflammatory vaginal dysbiosis. The Mediterranean diet, MD, containing foods rich in antioxidant compounds, is shown to be beneficial for inflammatory conditions. This study aimed to investigate the association between MD adherence and dietary total antioxidant capacity (DTAC) with BV.

Methods

This case–control study was conducted on 143 BV-affected and 151 healthy individuals aged between 15 and 45 years. The Amsel criteria were used to detect newly diagnosed patients with BV by a gynecologist. The 168-item food frequency questionnaire (FFQ) was used to record participants' dietary intakes in the last year. The reported data in the FFQ was used to measure adherence to the MD by calculating the Medi-Lite score and to measure the DTAC by calculating ferric-reducing antioxidant power, FRAP, based on the related databases. Logistic regression models were used to determine the association between Medi-Lite and DTAC and BV odds.

Results

The highest tertile of Medi-Lite score was associated with a reduced odds of BV in the crude model (Odds Ratio, OR: 0.49, 95% Confidence Interval, 95% CI 0.25, 0.96, P for trend: 0.023). This significant inverse association was not observed in the last model adjusted for age, body mass index (kg/m²), waist circumferences (cm), cigarette smoking, frequency of pregnancy, and physical activity (MET/h/d). In crude and adjusted odels, BV odds decreased in the highest tertile of vegetable (adjusted OR, aOR: 0.32, 95% CI 0.16, 0.63, P for trend: 0.001), fish (aOR: 0.46, 95% CI 0.25, 0.84, P for trend: 0.009), legumes (aOR: 0.26, 95% CI 0.14, 0.50, P for trend < 0.001), and meat (aOR: 0.29, 95% CI 0.15, 0.56, P for trend < 0.001) groups. There was no significant association between DTAC and BV odds.

Conclusions

The significant inverse association between the MD adherence and BV odds did not remain after modifying for confounders; besides, DTAC was not associated with BV odds. However, some of the MD components might be associated with a reduced odds of BV.

Macronutrient Intake and Insulin Resistance in 5665 Randomly Selected, Non-Diabetic U.S. Adults

The main goal of this investigation was to evaluate the relationships between several macronutrients and insulin resistance in 5665 non-diabetic U.S. adults. A secondary objective was to determine the extent to which the associations were influenced by multiple potential confounding variables. A cross-sectional design and 8 years of data from the 2011–2018 National Health and Nutrition Examination Survey (NHANES) were used to answer the research questions. Ten macronutrients were evaluated: total carbohydrate, starch, simple carbohydrate, dietary fiber, total protein, total fat, saturated, polyunsaturated, monounsaturated, and total unsaturated fat. The homeostatic model assessment (HOMA), based on fasting glucose and fasting insulin levels, was used to index insulin resistance. Age, sex, race, year of assessment, physical activity, cigarette smoking, alcohol use, and waist circumference were used as covariates. The relationships between total carbohydrate intake (F = 6.7, p = 0.0121), simple carbohydrate (F = 4.7, p = 0.0344) and HOMA-IR were linear and direct. The associations between fiber intake (F = 9.1, p = 0.0037), total protein (F = 4.4, p = 0.0393), total fat (F = 5.5, p = 0.0225), monounsaturated fat (F = 5.5, p = 0.0224), and total unsaturated fat (F = 6.5, p = 0.0132) were linear and inversely related to HOMA-IR, with 62 degrees of freedom. Starch, polyunsaturated fat, and saturated fat intakes were not related to HOMA-IR. In conclusion, in this nationally representative sample, several macronutrients were significant predictors of insulin resistance in U.S. adults.

Food and Nutrition Myths among Future Secondary School Teachers: A Problem of Trust in Inadequate Sources of Information

The Internet and social networks are full of nutrition information, offering people guidance to make healthy eating choices. These sources always present themselves as a gateway to reliable information on healthy eating; however, too often this is not the case. Far from being trustworthy, there are usually plenty of food myths. A food myth is a widespread false belief about food, nutrition, and eating facts that gives rise to certain behaviors, from fashionable trends to diets. Academic training is a valuable tool to combat food myths and the pseudoscience linked to them, but educators must participate in this battle. To test this idea, we analyzed the prevalence of nine highly popular food myths held by 201 secondary school Spanish teachers. The aim was to assess whether expertise in science areas prevents teachers from falling into these food misconceptions. Our study results showed that food myths are held regardless of specialty area. The power of the media in popularizing and spreading nutrition myths among educators may be the cause, even more potent than academic training. We conclude that since scientific knowledge is not enough to erase food myths, we need further actions if we aim to prevent the problems that food myths may cause.

A head-to-head comparison review of biological and toxicological studies of isomaltulose, d-tagatose, and trehalose on glycemic control

Diabetes mellitus is the most common metabolic disorder contributing to significant morbidity and mortality in humans. Different preventive and therapeutic agents, as well as various pharmacological strategies or non-pharmacological tools, improve the glycemic profile of diabetic patients. Isomaltulose, d-tagatose, and trehalose are naturally occurring, low glycemic sugars that are not synthesized by humans but widely used in food industries. Various studies have shown that these carbohydrates can regulate glucose metabolism and provide support in maintaining glucose homeostasis in patients with diabetes, but also can improve insulin response, subsequently leading to better control of hyperglycemia. In this review, we discussed the anti-hyperglycemic effects of isomaltulose, D-tagatose, and trehalose, comparing their properties with other known sweeteners, and highlighting their importance for the development of the pharmaceutical and food industries.

Cumulative soft drink consumption is associated with insulin resistance in Mexican adults

BACKGROUND

Insulin resistance (IR) is an important risk factor for type 2 diabetes (T2D) and other cardiometabolic diseases. Recent studies suggest that soft drink consumption could increase IR. However, inconsistent findings have been observed.

OBJECTIVE

The aim was to estimate the association between the cumulative consumption of soft drinks and IR by means of the HOMA-IR in Mexican adults.

METHODS

We analyzed the association between cumulative consumption of soft drinks and HOMA-IR change after 7 y of follow-up in participants (n = 1073) of the Health Workers Cohort Study. Soft drink consumption was estimated by food-frequency questionnaires. Insulin was measured by chemiluminescence, and fasting glucose was measured with the enzymatic colorimetric method. HOMA-IR was computed as fasting insulin (mIU/L) × fasting glucose (mmol/L)/22.5. To assess the relation between cumulative soft drink consumption and HOMA-IR change, we performed robust linear regression models. Additionally, we used fixed-effects models to estimate the association between changes in soft drink consumption and change in HOMA-IR.

RESULTS

At baseline, the average age was 44 y. Mean cumulative soft drink consumption was 0.42 servings/d. Median HOMA-IR increased from 1.5 at baseline to 2.0 at follow-up. Soft drink consumption was positively associated with HOMA-IR change. In the multiple linear regression analysis, for each increase in the consumption of 2 (355 mL) soft drinks/d, the average change between baseline and follow-up HOMA-IR showed an increase of 1.11 units (95% CI: 0.74, 1.48).

CONCLUSIONS

Our data support the hypothesis that, in Mexican adults, a higher soft drink consumption is associated with an increase in HOMA-IR, despite known risk factors. These findings support the need for reinforcing policies to reduce soft drink consumption in our population.

Plant-based diets, insulin sensitivity and inflammation in elderly men with chronic kidney disease

BACKGROUND

In persons with CKD, adherence to plant-based diets is associated with lower risk of CKD progression and death, but underlying mechanisms are poorly characterized. We here explore associations between adherence to plant-based diets and measures of insulin sensitivity and inflammation in men with CKD stages 3-5.

METHODS

Cross-sectional study including 418 men free from diabetes, aged 70-71 years and with cystatin-C estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m² and not receiving kidney-specific dietetic advice. Information from 7-day food records was used to evaluate the adherence to a plant-based diet index (PBDi), which scores positively the intake of plant-foods and negatively animal-foods. Insulin sensitivity and glucose disposal rate were assessed with the gold-standard hyperinsulinemic euglycemic glucose clamp technique. Inflammation was evaluated by serum concentrations of C-reactive protein (CRP) and interleukin (IL)-6. Associations were explored through linear regression and restricted cubic splines.

RESULTS

The majority of men had CKD stage 3a. Hypertension and cardiovascular disease were the most common comorbidities. The median PBDi was 38 (range 14-55). Across higher quintiles of PBDi (i.e. higher adherence), participants were less often smokers, consumed less alcohol, had lower BMI and higher eGFR (P for trend <0.05 for all). Across higher PBDi quintiles, patients exhibited higher insulin sensitivity and lower inflammation (P for trend <0.05). After adjustment for eGFR, lifestyle factors, BMI, comorbidities and energy intake, a higher PBDi score remained associated with higher glucose disposal rate and insulin sensitivity as well as with lower levels of IL-6 and CRP.

CONCLUSION

In elderly men with non-dialysis CKD stages 3-5, adherence to a plant-based diet was associated with higher insulin sensitivity and lower inflammation, supporting a possible role of plant-based diets in the prevention of metabolic complications of CKD.

Diet and liver cancer risk: a narrative review of epidemiological evidence

Primary liver cancer is the third leading cause of cancer-related death worldwide. Most patients are diagnosed at late stages with poor prognosis; thus, identification of modifiable risk factors for primary prevention of liver cancer is urgently needed. The well-established risk factors of liver cancer include chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), heavy alcohol consumption, metabolic diseases such as obesity and diabetes, and aflatoxin exposure. However, a large proportion of cancer cases worldwide cannot be explained by current known risk factors. Dietary factors have been suspected as important, but dietary aetiology of liver cancer remains poorly understood. In this review, we summarised and evaluated the observational studies of diet including single nutrients, food and food groups, as well as dietary patterns with the risk of developing liver cancer. Although there are large knowledge gaps between diet and liver cancer risk, current epidemiological evidence supports an important role of diet in liver cancer development. For example, exposure to aflatoxin, heavy alcohol drinking and possibly dairy product (not including yogurt) intake increase, while intake of coffee, fish and tea, light-to-moderate alcohol drinking and several healthy dietary patterns (e.g. Alternative Healthy Eating Index) may decrease liver cancer risk. Future studies with large sample size and accurate diet measurement are warranted and need to consider issues such as the possible aetiological heterogeneity between liver cancer subtypes, the influence of chronic HBV or HCV infection, the high-risk populations (e.g. cirrhosis) and a potential interplay with host gut microbiota or genetic variations.

Interplay of an Obesity-Based Genetic Risk Score with Dietary and Endocrine Factors on Insulin Resistance

This study aimed to nutrigenetically screen gene-diet and gene-metabolic interactions influencing insulin resistance (IR) phenotypes. A total of 232 obese or overweight adults were categorized by IR status: non-IR (HOMA-IR (homeostatic model assessment - insulin resistance) index ≤ 2.5) and IR (HOMA-IR index > 2.5). A weighted genetic risk score (wGRS) was constructed using 95 single nucleotide polymorphisms related to energy homeostasis, which were genotyped by a next generation sequencing system. Body composition, the metabolic profile and lifestyle variables were evaluated, where individuals with IR showed worse metabolic outcomes. Overall, 16 obesity-predisposing genetic variants were associated with IR (p < 0.10 in the multivariate model). The wGRS strongly associated with the HOMA-IR index (adj. R squared = 0.2705, p < 0.0001). Moreover, the wGRS positively interacted with dietary intake of cholesterol (P int. = 0.002), and with serum concentrations of C-reactive protein (P int. = 0.008) regarding IR status, whereas a negative interaction was found regarding adiponectin blood levels (P int. = 0.006). In conclusion, this study suggests that interactions between an adiposity-based wGRS with nutritional and metabolic/endocrine features influence IR phenotypes, which could facilitate the prescription of personalized nutrition recommendations for precision prevention and management of IR and diabetes.

Dietary Fiber, Whole Grains, and Head and Neck Cancer Prognosis: Findings from a Prospective Cohort Study

No studies, to date, have examined the relationship between dietary fiber and recurrence or survival after head and neck cancer diagnosis. The aim of this study was to determine whether pretreatment intake of dietary fiber or whole grains predicted recurrence and survival outcomes in newly diagnosed head and neck cancer (HNC) patients. This was a prospective cohort study of 463 participants baring a new head and neck cancer diagnosis who were recruited into the study prior to the initiation of any cancer therapy. Baseline (pre-treatment) dietary and clinical data were measured upon entry into the study cohort. Clinical outcomes were ascertained at annual medical reviews. Cox proportional hazard models were fit to examine the relationships between dietary fiber and whole grain intakes with recurrence and survival. There were 112 recurrence events, 121 deaths, and 77 cancer-related deaths during the study period. Pretreatment dietary fiber intake was inversely associated with risk of all-cause mortality (hazard ratio (HR): 0.37, 95% confidence interval (CI): 0.14–0.95, p_trend = 0.04). No statistically significant associations between whole grains and prognostic outcomes were found. We conclude that higher dietary fiber intake, prior to the initiation of treatment, may prolong survival time, in those with a new HNC diagnosis.

Effect of diet composition on insulin sensitivity in humans

Diet composition has a marked impact on the risk of developing type 2 diabetes and cardiovascular disease. Prospective studies show that dietary patterns with elevated amount of animal products and low quantity of vegetable food items raise the risk of these diseases. In healthy subjects, animal protein intake intensifies insulin resistance whereas plant-based foods enhance insulin sensitivity. Similar effects have been documented in patients with diabetes. Accordingly, pre-pregnancy intake of meat (processed and unprocessed) has been strongly associated with a higher risk of gestational diabetes whereas greater pre-pregnancy vegetable protein consumption is associated with a lower risk of gestational diabetes. Population groups that modify their traditional dietary habit increasing the amount of animal products while reducing plant-based foods experience a remarkable rise in the frequency of type 2 diabetes. The association of animal protein intake with insulin resistance is independent of body mass index. In obese individuals that consume high animal protein diets, insulin sensitivity does not improve following weight loss. Diets aimed to lose weight that encourage restriction of carbohydrates and elevated consumption of animal protein intensify insulin resistance increasing the risk of developing type 2 diabetes and cardiovascular disease. The effect of dietary components on insulin sensitivity may contribute to explain the striking impact of eating habits on the risk of type 2 diabetes and cardiovascular disease. Insulin resistance predisposes to type 2 diabetes in healthy subjects and deteriorates metabolic control in patients with diabetes. In nondiabetic and diabetic individuals, insulin resistance is a major cardiovascular risk factor.

Insulin-like growth factor I, binding proteins -1 and -3, risk of type 2 diabetes and macronutrient intakes in men

The insulin-like growth factor (IGF) axis may be involved in the development of type 2 diabetes. We examined the associations of IGF-I and IGF binding proteins (IGFBP)-1 and -3 with diabetes risk and evaluated macronutrient intakes related to the observed associations. In a nested case-control study of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish male smokers aged 50-69 years, the IGF variables were measured from baseline serum samples for a random sample of 310 men with diabetes diagnosed during a 12-year follow-up and for 310 controls matched by age, recruitment day and intervention group. Diet at baseline was assessed using a validated FFQ. The associations of IGF proteins with diabetes risk were estimated using conditional logistic regression and the associations with macronutrient intakes using linear regression. IGF-I and IGFBP-3 were not associated with the incidence of diabetes. Higher IGFBP-1 was associated with lower diabetes risk in an unadjusted crude model (OR 0·25; 95 % CI 0·15, 0·42 in the highest quartile compared with the lowest), but not after adjustment for BMI (corresponding OR 0·76; 95 % CI 0·41, 1·40). Intakes of carbohydrates, plant protein and milk protein associated positively and intake of meat protein and fat negatively with IGFBP-1 (P&lt;0·005). IGFBP-1 was inversely associated with diabetes risk, but the association was substantially dependent on BMI. The associations between macronutrient intakes and IGFBP-1 may reflect influences of nutrients or foods on insulin concentrations.

Association between Dietary Glycemic Index and Excess Weight in Pregnant Women in the First Trimester of Pregnancy

OBJECTIVE

To assess the association between dietary glycemic index (GI) and excess weight in pregnant women in the first trimester of pregnancy.

METHODS

A cross-sectional study in a sample of 217 pregnant women was conducted at the maternal-fetal outpatient clinic of the Hospital Geral de Fortaleza, Fortaleza, state of Ceará, Brazil, for routine ultrasound examinations in the period between 11 and 13 weeks + 6 days of gestation. Weight and height were measured and the gestational body mass index (BMI) was calculated. The women were questioned about their usual body weight prior to the gestation, considering the prepregnancy weight. The dietary GI and the glycemic load (GL) of their diets were calculated and split into tertiles. Analysis of variance (ANOVA) or Kruskal-Walls and chi-squared (χ2) statistical tests were employed. A crude logistic regression model and a model adjusted for confounding variables known to influence biological outcomes were constructed. A p-value < 0.05 was considered significant for all tests employed.

RESULTS

The sample group presented a high percentage of prepregnancy and gestational overweight (39.7% and 40.1%, respectively). In the tertile with the higher GI value, there was a lower dietary intake of total fibers (p = 0.005) and of soluble fibers (p = 0.008). In the third tertile, the dietary GI was associated with overweight in pregnant women in the first trimester of gestation, both in the crude model and in the model adjusted for age, total energy intake, and saturated fatty acids. However, this association was not observed in relation to the GL.

CONCLUSION

A high dietary GI was associated with excess weight in women in the first trimester of pregnancy.

Dietary assessment of pre-diabetic patients by using food frequency questionnaire. A systematic review of study quality, study outcome, study questionnaire and their relative validity and reliability

BACKGROUND

The contribution of dietary factors in the development and progression of pre-diabetes has been increasingly recognized. However, due to high variability in dietary habits measurement of dietary intake remains one of the most challenging tasks in this population. Food frequency questionnaire (FFQ) which investigates usual dietary intake can be used to identify frequent consumption of foods such as dietary fat, fiber, grains that are linked to the risk of pre-diabetes.

METHOD

This systematic review was conducted to identify and describe FFQs that measure dietary intake of pre-diabetic patients and to examine their relative validity and reliability. The systematic search was done through electronic databases such as PubMed, CINAHL, PsycINFO, ProQuest and Scopus. Methodological quality of included studies and results of study outcome was also summarized in this review.

RESULT

The search identified 445 papers, of which 18 studies reported 15 FFQs, met inclusion criteria. Most of the FFQs (n = 12) were semi-quantitative while three were frequency measures with portion size estimation of selected food items. Test-retest reliability of FFQ was reported in 7 (38.3%) studies with the correlation coefficient of 0.33-0.92. Relative validity of FFQ was reported in 16 (88.8%) studies with the range of correlation coefficient of 0.08-0.83. Dietary patterns rich in carbohydrate, fat, animal protein and n-3 fatty acids were associated with increased risk of pre-diabetes.

CONCLUSION

No well-established disease-specific FFQ identified in the literature. Development of a valid, practical and reliable tool is needed for better understanding of the impact of diet in pre-diabetic population.

Fat Versus Carbohydrate-Based Energy-Restricted Diets for Weight Loss in Patients With Type 2 Diabetes

PURPOSE OF REVIEW

The prevalence of combined obesity and diabetes has increased dramatically in the last few decades. Although medical and surgical weight management are variably effective in addressing this epidemic, it is essential to parallel these strategies with a hypocaloric diet comprising the appropriate macronutrient composition to induce weight loss, enhance glycemic control, and improve cardiovascular risk factors. This review reports the current evidence of the role of carbohydrates and fat-based diets for weight management in patients with combined type 2 diabetes (T2D) and obesity.

RECENT FINDINGS

Low-carbohydrate diets were shown to decrease postprandial glucose levels whereas high-carbohydrate, low-fat diets are considered cardio-protective. A diet with an optimal macronutrient composition remains uncertain for patients with combined T2D and obesity. Further research is still needed to define the best dietary composition that achieves the maximum benefits on weight management, glycemic control, and cardiovascular risk factors.

Diet and longevity: The effects of traditional eating habits on human lifespan extension

Since the dawn of time human beings have been trying to improve the quality of the existence and extend their lifespan. Genetic, environmental, behavioral and dietary factors influence the pathways that regulate aging and life expectancy, thus rendering longevity a very complex phenomenon. Although a long-lived elixir has not yet been found, physicians and scientists agree that nutrition has a major impact on the overall mortality and morbidity, hence becoming the subject of a widespread scientific research. This review describes, analyzes and compares the effects of different types of diets in reducing the onset of typical Western countries non-communicable diseases (NCDs) (cardiovascular diseases, tumors, chronic respiratory diseases, diabetes, etc.), thus increasing the average lifespan. It will first depict the most relevant characteristics, nutraceutical properties and effects on the populations of the Mediterranean, Japanese, Vegetarian and New Nordic Diet. Finally, it will describe the impact of different dietary restrictions in modulating the genetic pathways that regulate metabolism and aging. Overall, this work reinforces the evidence that specific eating habits, in addition to healthy and active lifestyles, are crucial to increase people’s health span and to achieve an optimal longevity.

A Plant-Based High-Carbohydrate, Low-Fat Diet in Overweight Individuals in a 16-Week Randomized Clinical Trial: The Role of Carbohydrates

The effects of carbohydrates on body weight and insulin sensitivity are controversial. In this 16-week randomized clinical trial, we tested the role of a low-fat, plant-based diet on body weight, body composition and insulin resistance. As a part of this trial, we investigated the role of changes in carbohydrate intake on body composition and insulin resistance. Participants (n = 75) were randomized to follow a plant-based high-carbohydrate, low-fat (vegan) diet (n = 38) or to maintain their current diet (n = 37). Dual-energy X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. A repeated measure ANOVA model was used to test the between-group differences from baseline to 16 weeks. A linear regression model was used to test the relationship between carbohydrate intake, and body composition and insulin resistance. Weight decreased significantly in the vegan group (treatment effect -6.5 [95% CI -8.9 to -4.1] kg; Gxt, p < 0.001). Fat mass was reduced in the vegan group (treatment effect -4.3 [95% CI -5.4 to -3.2] kg; Gxt, p < 0.001). HOMA-IR was reduced significantly in the vegan group (treatment effect -1.0 [95% CI -1.2 to -0.8]; Gxt, p = 0.004). Changes in consumption of carbohydrate, as a percentage of energy, correlated negatively with changes in BMI (r = -0.53, p < 0.001), fat mass (r = -0.55, p < 0.001), volume of visceral fat (r = -0.35, p = 0.006), and HOMA (r = -0.27, p = 0.04). These associations remained significant after adjustment for energy intake. Changes in consumption of total and insoluble fiber correlated negatively with changes in BMI (r = -0.43, p < 0.001; and r = -0.46, p < 0.001, respectively), fat mass (r = -0.42, p < 0.001; and r = -0.46, p < 0.001, respectively), and volume of visceral fat (r = -0.29, p = 0.03; and r = -0.32, p = 0.01, respectively). The associations between total and insoluble fiber and changes in BMI and fat mass remained significant even after adjustment for energy intake. Increased carbohydrate and fiber intake, as part of a plant-based high-carbohydrate, low-fat diet, are associated with beneficial effects on weight, body composition, and insulin resistance.

High dietary intake of branched-chain amino acids is associated with an increased risk of insulin resistance in adults

BACKGROUND

The aim of this study was to investigate the association between branched-chain amino acid (BCAA) intake and markers of insulin metabolism in adults.

METHODS

This cohort study was conducted within the framework of the Tehran Lipid and Glucose Study on 1205 subjects, aged ≥20 years, who were followed-up for a mean of 2.3 years. Dietary intake of BCAAs, including valine, leucine, and isoleucine, was determined using a valid and reliable food frequency questionnaire. Hyperinsulinemia, β-cell dysfunction, insulin resistance (IR), and insulin insensitivity were determined according to optimal cut-off values. Logistic regression was to estimate the occurrence of IR across tertiles of BCAA intake.

RESULTS

The mean (± SD) age and BCAA intake of participants (43% male) at baseline were 42.7 ± 13.1 years and 13.8 ± 5.1 g/day, respectively. The incidence of hyperinsulinemia, β-cell dysfunction, insulin insensitivity, and IR was 19.5%, 24.0%, 28.0%, and 12.5%, respectively. After adjustment for confounding variables, subjects in the highest tertile for total BCAAs (odds ratio [OR] 1.67; 95% confidence interval [CI] 1.03-2.71), leucine (OR 1.75; 95% CI 1.09-2.82), and valine (OR 1.61; 95% CI 1.01-2.60) intake had a greater risk of incident IR than subjects in the lowest tertile. A higher intake of isoleucine was not associated with risk of incident IR. There was no association of total BCAAs, leucine, isoleucine, and valine intake with the risk of hyperinsulinemia, insulin insensitivity, or β-cell dysfunction.

CONCLUSION

The findings of this study support the hypothesis that higher intakes of BCAAs may have adverse effects on the development of IR.

Fiber Intake and Insulin Resistance in 6374 Adults: The Role of Abdominal Obesity

A cross-sectional design was used to evaluate the relationship between fiber intake and insulin resistance, indexed using HOMA (homeostatic model assessment), in a National Health and Nutrition Examination Study (NHANES) sample of 6374 U.S. adults. Another purpose was to test the influence of covariates on the association. A third aim was to compare HOMA levels between two groups based on the recommended intake of 14 grams of fiber per 1000 kilocalories (kcal). Fiber intake was measured using a 24-hour recall. With demographic variables controlled, results showed that HOMA differed across High, Moderate, and Low fiber categories (F = 5.4, p = 0.0072). Adjusting for the demographic variables, the possible misreporting of energy intake, smoking, and physical activity strengthened the relationship (F = 8.0, p = 0.0009), which remained significant after adjusting for body fat (F = 7.0, p = 0.0019) and body mass index (BMI) (F = 4.9, p = 0.0108), with the other covariates. However, the fiber-HOMA relationship was eliminated after adjusting for waist circumference (F = 2.3, p = 0.1050). Dividing participants based on the recommended 14-gram standard resulted in meaningful HOMA differences (F = 16.4, p = 0.0002), and the association was not eliminated after controlling for waist circumference. Apparently, adults with high fiber consumption have less insulin resistance than their counterparts. However, much of the association is due to differences in waist circumference, unless the recommended intake of fiber is attained.

The Effect of a Diet Moderately High in Protein and Fiber on Insulin Sensitivity Measured Using the Dynamic Insulin Sensitivity and Secretion Test (DISST)

Evidence shows that weight loss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD), that was intended to be low in fat and relatively high in carbohydrate (n = 42) or to a relatively high protein (up to 30% of energy), relatively high fibre (>30 g/day) diet (HPHFib) (n = 47) for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method—the Dynamic Insulin Sensitivity and Secretion Test (DISST). Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8%, 4.5%; p = 0.013) in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.

Dietary food patterns and glucose/insulin homeostasis: a cross-sectional study involving 24,182 adult Americans

Aim

To investigate the association of major dietary patterns with glucose and insulin homeostasis parameters in a large American sample. The association between dietary patterns (DP) derived via principal components analysis (PCA), with glucose/insulin homeostasis parameters was assessed. The likelihood of insulin resistance (IR) across the DPs quarters was also explored.

Method

The United States National Health and Nutrition Examination Survey (NHANES) participants during 2005–2012 were included if they underwent measurement of dietary intake as well as glucose and insulin homeostasis parameters. Analysis of covariance (ANCOVA) and adjusted logistic and linear regression models were employed to account for the complex survey design and sample weights.

Results

A total of 24,182 participants were included; 48.9% (n = 11,815) were men. Applying PCA revealed three DP (56.8% of variance): the first was comprised mainly of saturated fat (SFA), total fat, mono-unsaturated fatty acids (MUFA) and carbohydrate (CHO); the second is highly enriched with vitamins, trace elements and dietary fiber; and the third was composed of polyunsaturated fatty acids (PUFA), cholesterol and protein. Among the total population, after adjustment for age, sex, race, C-reactive protein, smoking, and physical activity, glucose homeostasis factors, visceral adiposity index and lipid accumulation product improved across the quarters of the first and third DP; and a reverse pattern with the second DP. The same trend was observed for the non-diabetic subjects. Moreover, subjects with higher adherence to the first and third DP had higher likelihood for developing IR, whereas there was a lower likelihood for the second DP.

Conclusion

This study shows that the DP heavily loaded with CHO, SFA, PUFA, protein, total fat and MUFA as well as high-cholesterol-load foods is associated with impaired glucose tolerance; in contrast, the healthy pattern which is high in vitamins, minerals and fiber may have favourable effects on insulin sensitivity and glucose tolerance.

Qualitative and Quantitative Evaluation of Dietary Intake in Patients with Non-Alcoholic Steatohepatitis

There are very few reports about the intake of nutrients for the development or progression of non-alcoholic steatohepatitis (NASH). The aim of this study was to identify the dietary habits and the nutrient intake in patients with NASH, in comparison to chronic hepatitis C (HCV)-related patients. We prospectively evaluated the intake of macronutrients and micronutrients in 124 NAFLD and 162 HCV patients, compared to 2326 subjects as a control group. We noticed major differences in macro- and micronutrients intakes in NASH and HCV patients compared to controls. Proteins, carbohydrate (glucose, fructose, sucrose, maltose and amide), saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), folic acid, vitamin A and C (p < 0.0001), and thiamine (p < 0.0003) ingestion was found to be higher in patients with NASH, while total lipids, polyunsaturated fatty acid (PUFA), riboflavin and vitamin B6 daily intake were lower compared to controls (p < 0.0001). Similarly, NASH patients had significantly reduced carbohydrate intake (p < 0.0001) and an increased intake of calcium (p < 0.0001) compared to HCV positive patients. Finally, we showed in NASH males an increase in the intake of SFA, PUFA, soluble carbohydrates (p < 0.0001) and a decrease in the amount of fiber (p < 0.0001) compared to control males. In NASH female population, we showed an increase of daily total calories, SFA, MUFA, soluble carbohydrates, starch and vitamin D ingested (p < 0.0001) with a reduction of fibers and calcium (p < 0.0001) compared to control females. This study showed how NASH patients’ diets, in both male and females, is affected by a profound alteration in macro- and micronutrients intake.

The Effect of Dietary Glycemic Properties on Markers of Inflammation, Insulin Resistance, and Body Composition in Postmenopausal American Women: An Ancillary Study from a Multicenter Protein Supplementation Trial

Controversy exists as to whether high glycemic index/glycemic load (GI/GL) diets increase the risk of chronic inflammation, which has been postulated as a pathogenic intermediary between such diets and age-related alterations in body composition and insulin resistance. We conducted an ancillary study to a randomized, double-blind trial comparing the effects of a whey protein supplement (PRO, n = 38) and a maltodextrin supplement (CHO, n = 46) on bone density to evaluate the impact of a calibrated increase in GI/GL on inflammation, insulin resistance, and body composition in a healthy aging population. Markers of inflammation, HOMA, body composition, and GI/GL (estimated from 3-day food records) were assessed at baseline and 18 months. By 18 months, the GL in the CHO group increased by 34%, 88.4 ± 5.2 → 118.5 ± 4.9 and did not change in the PRO group, 86.5 ± 4.1 → 82.0 ± 3.6 (p < 0.0001). Despite this change there were no differences in serum CRP, IL-6, or HOMA at 18 months between the two groups, nor were there significant associations between GL and inflammatory markers. However, trunk lean mass (p = 0.0375) and total lean mass (p = 0.038) were higher in the PRO group compared to the CHO group at 18 months There were also significant associations for GL and change in total fat mass (r = 0.3, p = 0.01), change in BMI (r = 0.3, p = 0.005), and change in the lean-to-fat mass ratio (r = −0.3, p = 0.002). Our data suggest that as dietary GL increases within the moderate range, there is no detectable change in markers of inflammation or insulin resistance, despite which there is a negative effect on body composition.

Associations of Dietary Glucose, Fructose, and Sucrose with β-Cell Function, Insulin Sensitivity, and Type 2 Diabetes in the Maastricht Study

The associations of glucose, fructose, and sucrose intake with type 2 diabetes mellitus (T2DM) have been inconsistent. Furthermore, there is a lack of studies focusing on early markers of T2DM that provide insight into the process of T2DM progression: impaired pancreatic β-cell function (BCF) and insulin sensitivity. This study evaluated associations cross-sectionally in a population-based cohort consisting of 2818 individuals (mean ± SD age 59.7 ± 8.18, 49.5% male, n = 120 newly diagnosed T2DM). Glucose, fructose, and sucrose intake were assessed by a food frequency questionnaire. Glucose metabolism status, insulin sensitivity, and BCF were measured by a seven-points oral glucose tolerance test. Linear regression analysis revealed a positive association of glucose intake with insulin sensitivity in the fully adjusted model (standardized beta (95% CI) 0.07 (0.05, 0.14) SD for ≥23 g vs. <10 g of glucose). Fructose and sucrose intake were not associated with insulin sensitivity after full adjustments. In addition, no associations of dietary glucose, fructose, and sucrose with BCF were detected. In conclusion, higher intake of glucose, not fructose and sucrose, was associated with higher insulin sensitivity, independent of dietary fibre. No convincing evidence was found for associations of dietary glucose, fructose, and sucrose with BCF in this middle-aged population.

Consumption of red and processed meat and refined grains for 4weeks decreases insulin sensitivity in insulin-resistant adults: A randomized crossover study

BACKGROUND

Red and processed meat and refined grains are associated with an increased risk of type 2 diabetes. Interventions are limited. We hypothesized that a diet high in red and processed meat and refined grains (HMD) would decrease insulin sensitivity compared to a diet high in whole grains, nuts, dairy and legumes with no red meat (HWD).

METHODS

Forty-nine subjects without diabetes [15 men and 34 women, age, 35.6±15.7 years, body mass index (BMI), 27±5.9kg/m²] underwent two 4-week weight-stable dietary interventions in a randomized crossover design. The insulin sensitivity index (ISI) was calculated from the last 30min of a continuous low-dose insulin (25mU/kg·h) and glucose (4mg/kg·min) infusion test (LDIGIT _120-150min) at the end of each diet.

RESULTS

The population fell into two very discrete groups: those with a very low insulin response in the LDIGIT _120-150min on HMD (Group 1<56pmol/L, n=24), and those with relatively normal insulin responses (Group 2>56pmol/L, n=25). Group 2 had significantly higher insulin concentrations [(median and interquartile range) 153, 180 for HMD vs. 123, 149pmol/L for HWD; P=0.019] and glucose concentrations [(mean±standard deviation) 7.4±1.3 for HMD vs.6.7±1.2mmol/L for HWD; P=0.05], resulting in a significantly decreased ISI [(median and interquartile range) 21.1, 34.2 for HMD vs. 31.6, 39.4 for HWD; P=0.014] compared to HWD. Log ISI after HMD was significantly correlated with BMI (r=-0.5; P=0.009), fat mass (r=-0.55; P=0.004) and self-reported activity levels (r=-0.45; P=0.024).

CONCLUSIONS

A dietary pattern high in red and processed meat and refined grains decreased insulin sensitivity compared to a dietary pattern high in whole grains, nuts, dairy products and legumes only in relatively insulin-resistant adults.

Low glycemic load diets protect against metabolic syndrome and Type 2 diabetes mellitus in the male Nile rat

BACKGROUND

Dietary modification helps prevent and manage Metabolic Syndrome (MetS) and Type 2 Diabetes Mellitus (T2DM) in humans and Nile rats. Specifically fibrous legumes, like lentils, benefit humans, but whether this reflects a specific change in the Glycemic Load (GLoad) remains controversial. Accordingly, low-GLoad foods were tested in the glucose-sensitive Nile rat.

METHODS

131 male Nile rats aged 3 weeks to 15 months were challenged during four experiments with 15 dietary exposures that varied Glycemic Index (GI, 36-88), GLoad (102-305/2000 kcal), and cumulative GLoad (Cum GLoad=days×GLoad, 181-537g total glucose).

RESULTS

Lentil diets with low GLoads (102, 202) prevented, delayed, reduced, even reversed the progress of MetS and T2DM as measured by blood glucose (fasting, random, and oral glucose tolerance test) and plasma lipid parameters (plasma cholesterol and triglycerides) plus necropsy findings (liver and kidney pathology plus adipose reserves). The benefit from lentils exceeded dietary factors such as macronutrient composition (%Energy from carbohydrate:fat:protein, between 70:10:20 to 40:40:20), total fiber (0-24%), or dietary caloric density (2.9-4.7 kcal/g). The benefit of a low GLoad applied equally to rats inherently susceptible or resistant to T2DM, based on random glucose above or below 75 mg/dl, respectively, during interventions of 7-17 weeks.

CONCLUSIONS

Measuring total food intake and the novel concept of Cum GLoad during growth generated strong correlations (up to r=0.93) between Cum GLoad and parameters of MetS and T2DM, especially during sexual maturation. The present experiments confirm the applicability of male Nile rats to diet-induced human T2DM, and suggest dietary compositions to deter MetS and T2DM in humans.

Sugar-Sweetened Beverage but Not Diet Soda Consumption Is Positively Associated with Progression of Insulin Resistance and Prediabetes

BACKGROUND

Previous studies have shown an inconsistent relation between habitual beverage consumption and insulin resistance and prediabetes.

OBJECTIVE

The objective of the present study was to test the hypothesis that the consumption of sugar-sweetened beverages (SSBs), rather than diet soda, is associated with long-term progression of insulin resistance and the development of prediabetes.

METHODS

We analyzed the prospective association between cumulative mean consumption of SSBs or diet soda and incident prediabetes (n = 1685) identified across a median of 14 y of follow-up in participants [mean ± SD age: 51.9 ± 9.2 y; 59.6% women; mean ± SD body mass index (BMI; kg/m²): 26.3 ± 4.4] of the Framingham Offspring cohort. The prospective association between beverage consumption and change in homeostasis model assessment of insulin resistance (HOMA-IR; n = 2076) over ∼7 y was also analyzed. The cumulative mean consumption of SSBs and diet soda was estimated by using food-frequency questionnaires. Multivariable Cox proportional hazards models and linear regression models were implemented to estimate the HRs of incident prediabetes and change in HOMA-IR, respectively.

RESULTS

After adjustment for multiple potential confounders, including baseline BMI, we observed that SSB intake was positively associated with incident prediabetes (P-trend < 0.001); the highest SSB consumers (>3 servings/wk; median: 6 servings/wk) had a 46% higher risk of developing prediabetes than did the SSB nonconsumers (HR: 1.46; 95% CI: 1.16, 1.83). Higher SSB intake was also associated with a greater increase in HOMA-IR (P-trend = 0.006). No prospective associations were observed between diet soda intake and risk of prediabetes (P-trend = 0.24) or changes in HOMA-IR (P-trend = 0.25). These associations were similar after additional adjustment for change in BMI.

CONCLUSION

Regular SSB intake, but not diet soda intake, is associated with a greater increase in insulin resistance and a higher risk of developing prediabetes in a group of middle-aged adults.

The Evidence Is In: Lifestyle Interventions Can Prevent Diabetes

Early epidemiological and clinical trials suggested that type 2 diabetes could be prevented or delayed by lifestyle modifications. The Finnish Diabetes Prevention Study and the Diabetes Prevention Programs provided conclusive evidence that type 2 diabetes could be prevented or delayed with modest lifestyle changes—5% to 7% loss of body weight and 150 min/week of physical activity. Both used intensive intervention strategies and continued support and follow-up to achieve study goals. Other smaller studies made similar observations. Various medications—metformin, acarbose, troglitazone and pioglitazone, orlistat, and rosiglitazone—and bariatric surgery have also been effective for the prevention or delay of diabetes. Nutrient factors studied include the contribution of a high dietary fat intake, especially saturated fat, to the development of diabetes and increased intake of fiber, whole grains, and alcohol to decreased risk. A review of the evidence led the American Diabetes Association to conclude that lifestyle interventions should be the first choice for prevention or delay of diabetes and that drug therapy should not be a substitute for lifestyle interventions—healthy and appropriate food choices and physical activity.

Prevalence and characteristics of impaired glucose metabolism in patients referred to comprehensive cardiac rehabilitation: the DANSUK study

BACKGROUND

Lifestyle and pharmacological interventions can delay the progression of impaired glucose tolerance (IGT) to type 2 diabetes (T2DM), and there is growing evidence that earlier detection of T2DM and intensified risk factor management may result in improved cardiovascular morbidity and mortality. We studied the prevalence of impaired glucose metabolism (T2DM, IGT and impaired fasting glucose; IFG) in patients referred to cardiac rehabilitation, and further studied whether we could identify groups in which an oral glucose tolerance test (OGTT) need not be performed.

METHODS

As part of a cardiac rehabilitation trial, 201 patients participated. Patients without a diagnosis of T2DM (N=159) underwent an OGTT 3 months after inclusion.

RESULTS

Forty-two patients (21%) had known T2DM at enrolment. Based on the OGTT, 26 patients (13%) had unrecognized T2DM, 36 (18%) had IGT and 19 (9%) were diagnosed with isolated IFG according to the World Health Organization definition. Using fasting plasma glucose alone, 19% of the patients with unrecognized T2DM and two-thirds of patients with IGT would be misclassified. Using IFG as a means to detect IGT showed a sensitivity of only 33% and a positive predictive value of 39%.

CONCLUSION

More than 60% of the patients (123/201) referred to cardiac rehabilitation had impaired glucose metabolism and 18% of the screened patients (29/159) would be misclassified if an OGTT was omitted. IFG and IGT did not identify the same patients or the same cardiovascular risk profile. An OGTT test should therefore be considered a constituent part of routine care management in cardiac rehabilitation settings.

Effect of an isocaloric diet containing fiber-enriched flour on anthropometric and biochemical parameters in healthy non-obese non-diabetic subjects

We studied the effect of soluble fiber-enriched products on anthropometric and biochemical variables in 30 healthy non-obese, non-diabetic subjects. This was a randomized, controlled crossover, single-blind, dietary intervention study performed for 8 weeks. Subjects received an isocaloric diet with fiber-enriched products for the first 4 weeks and with regular flour products for the following 4 weeks, or vice versa. Weight, height, measures of fat distribution (waist, hip circumference), glucose, insulin and triglycerides were measured at baseline, after 4 and 8 weeks of intervention. BMI and insulin sensitivity indices were calculated. Weight and BMI decreased in the first period of isocaloric diet in both groups, regardless of the type of flour consumed (weight p<0.01, p<0.001 respectively; BMI p = 0.01, p<0.001 respectively). At the end of the 8 weeks, weight and BMI further decreased in the group consuming the fiber-enriched diet (p<0.01). Insulin resistance, estimated with the Homeostasis Model Assessment index and the Lipid Accumulation Product index, improved in all subjects after the fiber-enriched flour diet (p = 0.03, p = 0.02, respectively). In conclusion, an isocaloric diet supplemented with fiber-enriched products may improve measures of fatness and insulin sensitivity in healthy non-obese non-diabetic subjects. We might hypothesize a similar effect also in subjects with metabolic abnormalities.

Paediatric non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFLD) is a progressive disease that encompasses a spectrum of liver diseases, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Data related to survival in children are scarce, but these data firmly associate NAFLD with higher risks of hepatic and non-hepatic morbidities and mortalities compared with the general population. More recently, the association between NAFLD and cardiovascular disease among children has increasingly been recognized. Given that obesity is a major risk factor for the disease, paediatric NAFLD is becoming a global issue, paralleling the dramatic rise in obesity worldwide. NASH, which is more common in obese children, has the potential to advance to liver fibrosis and failure. It is unclear why certain patients undergo such transformation but this susceptibility is likely related to an interaction between a genetically susceptible host and the surrounding environment. Currently, treatment is largely conservative and includes lifestyle modification, attainable through healthy weight reduction via diet and exercise. In this review, current knowledge about NAFLD in children is summarized. This review aims to increase the awareness of the medical community about a hidden public health issue and to identify current gaps in the literature while providing directions for future research.

Fiber intake and risk of subsequent prostate cancer in Japanese men

BACKGROUND

Dietary fiber may reduce the risk of prostate cancer, possibly by increasing circulating concentrations of sex hormone-binding globulin and improving insulin sensitivity. However, results from previous epidemiologic studies of fiber intake and prostate cancer are inconsistent, and to our knowledge, no study has comprehensively evaluated the effects of soluble and insoluble fiber on prostate cancer in Asia.

OBJECTIVE

The objective was to examine the association between fiber intake and prostate cancer in Japanese men.

DESIGN

We conducted a population-based prospective study in 43,435 Japanese men aged 45-74 y. Participants responded to a validated questionnaire, which included 138 food items. Follow-up was from 1995 through 2009. HRs and 95% CIs of incidence were calculated according to quartiles of fiber intake.

RESULTS

During the 11.6-y follow-up, of the 825 men newly diagnosed with prostate cancer, 213 had advanced-stage cancer, 582 had organ-localized disease, and 30 had an undetermined stage of disease. Among them, 217 cases were detected by subjective symptoms. Total fiber was not associated with total or advanced prostate cancer, with respective multivariable HRs for the highest and lowest quartiles of 1.00 (95% CI: 0.77, 1.29; P-trend = 0.97) and 0.67 (95% CI: 0.42, 1.07; P-trend = 0.30). Total fiber and insoluble fiber intake were associated with a decreased risk of advanced cancers detected by subjective symptoms, with multivariate HRs (95% CIs) across increasing quartiles of 1.00, 0.58, 0.62, and 0.44 (0.21, 0.92; P-trend = 0.05) for total fiber and 1.00, 0.60, 0.52, and 0.46 (0.22, 0.93; P-trend = 0.04) for insoluble fiber. Soluble fiber intake showed no association with prostate cancer.

CONCLUSIONS

Dietary fiber is inversely associated with advanced prostate cancer detected by subjective symptoms even among populations with relatively low intake, such as Japanese. These results suggest that a very low intake of dietary fiber is associated with an increased risk of prostate cancer.

Questionnaire survey on lifestyle of patients with nonalcoholic steatohepatitis

Lack of exercise and excessive food intake are known to be the important causes of nonalcoholic steatohepatitis (NASH). To elucidate the relationship between lifestyle and NASH, we surveyed exercise and dietary habits, comparing them among 171 biopsy-proven NASH patients, 29 nonalcoholic fatty liver (NAFL) patients and 49 normal subjects. Dietary habits including the duration of dinner time, amount of rice at dinner, and weekly frequencies of meat, fries, Chinese noodles, sweets, and instant food consumption were significantly different in male NASH patients compared to normal male subjects. In women, differences were seen in the amount of rice at dinner, frequency of eating out, and proclivity for sweets. In male NASH patients, the frequency of physical exercise was significantly lower. The lifestyle tendencies of NASH were almost similar to those of NAFL. In the comparison between obese NASH and non-obese NASH, no clear lifestyle differences were found. In conclusion, the most striking result of this survey was that the lifestyle of males contributed significantly to the development of NASH. These results point to treatment of NASH in males. In female NASH patients, lifestyle differences were minimal, and the effects of other factors such as genetic background will need to be investigated.

The effect of Mediterranean diet on the development of type 2 diabetes mellitus: a meta-analysis of 10 prospective studies and 136,846 participants

OBJECTIVE

The purpose of this work was to meta-analyze prospective studies that have evaluated the effect of a Mediterranean diet on the development of type 2 diabetes.

MATERIALS/METHODS

PubMed, Embase and the Cochrane Central Register of Controlled Trials databases were searched up to 20 November 2013. English language publications were allocated; 17 original research studies (1 clinical trial, 9 prospective and 7 cross-sectional) were identified. Primary analyses were limited to prospective studies and clinical trials, yielding to a sample of 136,846 participants. A systematic review and a random effects meta-analysis were conducted.

RESULTS

Higher adherence to the Mediterranean diet was associated with 23% reduced risk of developing type 2 diabetes (combined relative risk for upper versus lowest available centile: 0.77; 95% CI: 0.66, 0.89). Subgroup analyses based on region, health status of participants and number of confounders controlling for, showed similar results. Limitations include variations in Mediterranean diet adherence assessment tools, confounders' adjustment, duration of follow up and number of events with diabetes.

CONCLUSIONS

The presented results are of major public health importance, since no consensus exists concerning the best anti-diabetic diet. Mediterranean diet could, if appropriately adjusted to reflect local food availability and individual's needs, constitute a beneficial nutritional choice for the primary prevention of diabetes.

Television screen time, but not computer use and reading time, is associated with cardio-metabolic biomarkers in a multiethnic Asian population: a cross-sectional study

Background

Recent evidence shows that sedentary behaviour may be an independent risk factor for cardiovascular diseases, diabetes, cancers and all-cause mortality. However, results are not consistent and different types of sedentary behaviour might have different effects on health. Thus the aim of this study was to evaluate the association between television screen time, computer/reading time and cardio-metabolic biomarkers in a multiethnic urban Asian population. We also sought to understand the potential mediators of this association.

Methods

The Singapore Prospective Study Program (2004–2007), was a cross-sectional population-based study in a multiethnic population in Singapore. We studied 3305 Singaporean adults of Chinese, Malay and Indian ethnicity who did not have pre-existing diseases and conditions that could affect their physical activity. Multiple linear regression analysis was used to assess the association of television screen time and computer/reading time with cardio-metabolic biomarkers [blood pressure, lipids, glucose, adiponectin, C reactive protein and homeostasis model assessment of insulin resistance (HOMA-IR)]. Path analysis was used to examine the role of mediators of the observed association.

Results

Longer television screen time was significantly associated with higher systolic blood pressure, total cholesterol, triglycerides, C reactive protein, HOMA-IR, and lower adiponectin after adjustment for potential socio-demographic and lifestyle confounders. Dietary factors and body mass index, but not physical activity, were potential mediators that explained most of these associations between television screen time and cardio-metabolic biomarkers. The associations of television screen time with triglycerides and HOMA-IR were only partly explained by dietary factors and body mass index. No association was observed between computer/ reading time and worse levels of cardio-metabolic biomarkers.

Conclusions

In this urban Asian population, television screen time was associated with worse levels of various cardio-metabolic risk factors. This may reflect detrimental effects of television screen time on dietary habits rather than replacement of physical activity.

Anthropometric and dietary predictors of insulin sensitivity in 10- to 14-year-old boys and girls

The high prevalence of pediatric obesity has made preventing chronic diseases through healthy lifestyle behaviours a priority within pediatrics. Examining the association between diet and insulin sensitivity (IS) in youth may provide important insights for tailoring preventative dietary interventions. The objective of this study was to explore the associations among anthropometry, diet, and IS in 10- to 14-year-olds. In this cross-sectional study, the primary outcome measure was IS, measured noninvasively using a 13C glucose breath test. Exposure variables included body mass index (BMI) z score and several dietary variables, including glycemic index (GI), glycemic load, and fiber, magnesium, vegetable and fruit, and fat intakes, all of which were derived from a validated, Web-based 24-h recall tool. Multiple regression analyses were performed for boys and girls separately. In total, 378 students (227 girls) aged 12.1 ± 1.2 years were studied. In this sample ∼24% of youth were considered overweight or obese (BMI z score = 0.41 ± 0.93). Multiple regression analyses showed that BMI z score was negatively and independently associated with 13C insulin sensitivity score (13CISS) in both boys and girls (boys: β = −0.501; girls: β = −0.446; both p < 0.001). GI was negatively and independently related to 13CISS in boys (β = −0.195, p < 0.05) but not in girls. Other dietary variables were not associated with IS. In addition to BMI z score, a low GI diet predicted 13CISS in boys but not in girls. This finding suggests that interventions that reduce BMI (in both sexes) and include a low GI diet among boys may improve IS.

The effect of dietary fibre on reducing the glycaemic index of bread

As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies have been carried out in order to decrease the GI of bread. The most relevant strategy that has been applied so far is the addition of fibre-rich flours or pure dietary fibre. However, the effectiveness of dietary fibre in bread in reducing the GI is controversial. The purpose of the present review was to discuss critically the effects obtained by adding different kinds of fibre to bread in order to modulate its glycaemic response. The studies were selected because they analysed in vivo whether or not dietary fibre, naturally present or added during bread making, could improve the glucose response. The reviewed literature suggests that the presence of intact structures not accessible to human amylases, as well as a reduced pH that may delay gastric emptying or create a barrier to starch digestion, seems to be more effective than dietary fibre per se in improving glucose metabolism, irrespective of the type of cereal. Moreover, the incorporation of technologically extracted cereal fibre fractions, the addition of fractions from legumes or of specifically developed viscous or non-viscous fibres also constitute effective strategies. However, when fibres or wholemeal is included in bread making to affect the glycaemic response, the manufacturing protocol needs to reconsider several technological parameters in order to obtain high-quality and consumer-acceptable breads.

Dietary fibre consumption and insulin resistance - the role of body fat and physical activity

The present study was conducted to determine the association between fibre intake and insulin resistance in 264 women using a cross-sectional design. Insulin resistance was indexed using homeostasis model assessment of insulin resistance (HOMA-IR) (US formula: fasting insulin (μU/ml) × fasting glucose (mg/dl)/405 international formula: fasting glucose (mmol/l) × fasting insulin (μU/l)/22.5). Fibre and energy consumption were assessed using 7 d weighed food records. Fibre was expressed as g/4184 kJ (1000 kcal). Body fat percentage (BF%) was measured using the BOD POD, and physical activity (PA) was ascertained using Actigraph accelerometers (Health One Technology) worn for seven consecutive days. Women with high total fibre intakes (F= 4·58, P= 0·0332) or high soluble fibre intakes (F= 7·97, P= 0·0051) had significantly less insulin resistance than their counterparts. Participants with high insoluble fibre intakes did not differ from their counterparts (F= 0·7, P= 0·6875). Adjusting for either PA or BF% weakened the relationships significantly. Controlling for BF% nullified the total fibre–HOMA-IR link (F= 1·96, P= 0·1631) and attenuated the association between soluble fibre and HOMA-IR by 32 % (F= 6·86, P= 0·0094). To create dichotomous variables, fibre intake and HOMA-IR were each divided into two categories using the median (low and high). In women who had high soluble fibre intake (upper 50 %), the OR of having an elevated HOMA-IR level was 0·58 (95 % CI 0·36, 0·94) times that of women with low soluble fibre intake (lower 50 %). After controlling for all of the potential confounding factors simultaneously, the OR was 0·52 (95 % CI 0·29, 0·93). High fibre intake, particularly soluble fibre, is significantly related to lower levels of insulin resistance in women. Part of this association is a function of differences in PA and BF%.

High intake of whole grains and beans pattern is inversely associated with insulin resistance in healthy Korean adult population

We investigated the association between dietary patterns and insulin resistance in the 3871 healthy Korean adults from the 2007 to 2008 Korea National Health and Nutrition Examination Survey. The whole grains and beans pattern was associated with lower prevalence of insulin resistance (OR for highest quintile=0.80, 95% CI=0.61-1.03, P for trend=0.013).

Dietary fiber intake is associated with HbA1c level among prevalent patients with type 2 diabetes in Pudong New Area of Shanghai, China

BACKGROUND

Dietary factors play an important role in glycemic control in diabetic patients. However, little is known about their effects among Chinese diabetic patients, whose diets are typically abundant in fiber and high in glycemic index (GI) values.

METHODOLOGY/PRINCIPAL FINDINGS

934 patients with type 2 diabetes and 918 healthy volunteers from Pudong New Area, Shanghai, China, were interviewed during the period of Oct-Dec, 2006 to elicit demographic characteristics and lifestyle factors. Dietary habits were assessed using a validated food frequency questionnaire. Anthropometric measurements, bio-specimen collection and biochemical assays were conducted at the interview according to a standard protocol. In this population, diabetic patients consumed lower levels of energy and macronutrients but had higher levels of fasting plasma glucose (FPG), glycolated hemoglobin A1c (HbA1c), triglyceride and body mass index than healthy adults. While the average consumption levels of the nutrients among diabetic patients did not vary along duration of the disease, the average levels of FPG and HbA1c increased with increasing duration. Regardless of diabetes duration, HbA1c level was observed lower in patients having a higher fiber or lower GI intake. Compared with those with the lowest tertile intake of fiber, the adjusted odds ratios (ORs) for poor glycemic control reduced from 0.75 (95%CI: 0.54-1.06) to 0.51 (95%CI: 0.34-0.75) with increasing tertile intake (P for trend <0.001).

CONCLUSIONS

Dietary fiber may play an important role in reducing HbA1c level. Increasing fiber intake may be an effective approach to improve glycemic control among Chinese diabetic patients.

Impact of postprandial glycaemia on health and prevention of disease

Postprandial glucose, together with related hyperinsulinemia and lipidaemia, has been implicated in the development of chronic metabolic diseases like obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). In this review, available evidence is discussed on postprandial glucose in relation to body weight control, the development of oxidative stress, T2DM, and CVD and in maintaining optimal exercise and cognitive performance. There is mechanistic evidence linking postprandial glycaemia or glycaemic variability to the development of these conditions or in the impairment in cognitive and exercise performance. Nevertheless, postprandial glycaemia is interrelated with many other (risk) factors as well as to fasting glucose. In many studies, meal-related glycaemic response is not sufficiently characterized, or the methodology with respect to the description of food or meal composition, or the duration of the measurement of postprandial glycaemia is limited. It is evident that more randomized controlled dietary intervention trials using effective low vs. high glucose response diets are necessary in order to draw more definite conclusions on the role of postprandial glycaemia in relation to health and disease. Also of importance is the evaluation of the potential role of the time course of postprandial glycaemia.

Associação entre índice glicêmico e carga glicêmica dietéticos e síndrome metabólica em idosos

OBJETIVO: Investigar a associação entre índice glicêmico (IG) e/ou carga glicêmica (CG) da dieta e síndrome metabólica (SM). MÉTODOS: Trata-se de estudo documental e do tipo caso-controle, com uma amostra de 229 idosos. Calcularam-se o IG e a CG, classificando-os em adequado (baixo) e inadequado (moderado e alto). Calculou-se ainda a prevalência de consumo dos alimentos, consumidos por pelo menos metade dos avaliados. A análise estatística dos dados foi efetuada por meio do teste c² e teste t de Student. Adotou-se p < 0,05 como nível de significância. RESULTADOS: Dos indivíduos estudados (n = 229), 74,2% pertenciam ao sexo feminino. A média de idade do grupo foi de 70,1 (6,4) anos. A média diária de IG do grupo caso foi de 62,3 (6,5), e do grupo controle de 62,1 (6,1), com p = 0,864. As médias diárias de CG não foram estatisticamente diferentes (p = 0,212), sendo a do grupo caso de 99,8 (33,8) e do grupo controle de 108,9 (45,7). Os alimentos consumidos tanto pelos casos como pelos controles, com maior contribuição ao IG, foram: pão, arroz, banana e açúcar refinado. CONCLUSÃO: No grupo avaliado, não houve associação entre índice glicêmico e carga glicêmica dietéticos e síndrome metabólica. O padrão identificado, no entanto, coloca portadores e não portadores em situação de risco à saúde, merecendo ações educativas.

Glycemic index and glycemic load in relation to glucose intolerance among Greenland's Inuit population

BACKGROUND

Intake of carbohydrates which elicit a large glycemic response is hypothesized to increase the risk of diabetes. However, studies assessing the relationship between glycemic index (GI) and glycemic load (GL) and diabetes are inconsistent. Only few studies have studied the relationship between GI and GL and markers of glucose metabolism, mostly in western populations.

OBJECTIVE

To determine the relationship between GI and GL and indices of glucose metabolism and prevalence of diabetes in Greenland's Inuit population.

DESIGN

The Inuit Health in Transition Study is a geographically representative cross-sectional study among aged ≥18years. Diet was assessed using a 67-item food frequency questionnaire. Logistic and linear regression was used to assess the association between GI and GL and diabetes, impaired fasting glucose, impaired glucose tolerance, HbA(1c), fasting plasma glucose, 2h plasma glucose, HOMA2-IR and HOMA2-%β.

RESULTS

No association was found between GI and GL and diabetes. GL was significantly inversely associated with IFG (OR: 0.91 (0.84-0.98)). While GI was positively associated with FPG, GL was positively associated with both HOMA2-IR and HOMA2-%β and inversely associated with IFG.

CONCLUSION

These findings do not support a link between dietary GI or GL and risk of type 2 diabetes among Greenland's Inuit population.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.