A protein-enriched low glycemic index diet with omega-3 polyunsaturated fatty acid supplementation exerts beneficial effects on metabolic control in type 2 diabetes

Evaluation of hypoglycemic therapeutics and nutritional supplementation for type 2 diabetes mellitus management: An insight on molecular approaches

OBJECTIVE

This review aims to summarize the current management of type 2 diabetes principles, including oral hypoglycemic agents, types of insulin administration, diet maintenance, and various molecular approaches.

METHODS

A literature search was conducted in different databases such as Scopus, ScienceDirect, Google Scholar, and Web of Science by using the following keywords: type-2 diabetes mellitus (T2DM), first-line and second-line treatment, oral hypoglycemic agents, insulin administration, diet/nutritional therapy, gene and stem cell therapy, and diabetic complications.

RESULTS

The first-line treatment of T2DM includes administering oral hypoglycemic agents (OHAs) and second-line treatment by insulin therapy and some OHAs like Sulfonylurea's (SU). The oral hypoglycemic or oral antidiabetic drugs have the function of lowering glucose in the blood. Insulin therapy is recommended for people with A1C levels > 7.0, and insulin administration is evolved drastically from the syringe, pump, pen, inhalation, insulin jet, and patch. The use of OHAs and insulin therapy during glycemic control has a severe effect on weight gain and other side effects. Hence, diet maintenance (macro and micronutrients) and nutritional therapy guidelines were also reviewed/recommended for safe T2DM management. Besides, the recent progress in molecular approaches that focuses on identifying new targets for T2DM (i.e.) consisting of gene therapy, stem cell therapy, and the modulation of insulin signaling pathways for the regulation of glucose storage and uptake also discussed.

CONCLUSION

The analysis of all these key factors is necessary to develop a potential agent to cure T2DM and suggest that a combination of therapies will pave the way for advanced management of T2DM.

Sacha inchi (Plukenetia volubilis L.): An emerging source of nutrients, omega-3 fatty acid and phytochemicals

Sacha inchi (Plukenetia volubilis) (SI) is an oleaginous plant producing oil and protein-rich seeds. It has been cultivated for centuries and is native to the tropical rainforest of the Amazon region of South America including parts of Peru and northwestern Brazil. At present, SI seeds are emerging as a potential source of macro- and micronutrients, α-linolenic acid and phytochemicals. This review attempts to elucidate the nutrients, phytonutrients, safety, toxicity, health benefits and food applications of SI seed. Recent scientific studies have associated the consumption of SI seed/oil with reduced risk of chronic inflammatory diseases. However, lack of awareness and in-depth understanding has resulted in it being neglected both at the consumer and industrial level. In all, SI is an underutilized and undervalued oleaginous crop which not only has the potential to mitigate food and nutritional insecurity but also offers humongous opportunities for the development of novel value-added food products.

Cardio-Metabolic Benefits of Walnuts in Type 2 Diabetes Mellitus: A Literature Review

Diabetes and its complications are main causes of morbidity and mortality among adults in the USA. An increase in the number of individuals with diabetes is primarily attributed to changes in dietary patterns including increased consumption of obesogenic foods and beverages. Many individuals who are overweight and obese show signs of insulin resistance and are at increased risk of Type 2 diabetes mellitus (T2DM) and cardiovascular disease. Lifestyle interventions (i.e., physical activity and nutrition) are the cornerstone of T2DM management and prevention. Prior research attests to the health benefits of consuming nuts, which have a substantial amount of mono- and polyunsaturated fatty acids, for individuals at risk for or with T2DM, and walnuts appear to be particularly promising. Walnuts are rich in nutrients, minerals, antioxidants, and vitamins that can contribute to improved cardio-metabolic risk factors in individuals at risk for or with T2DM. This review assesses the cardio-metabolic benefits of walnuts in T2DM. The authors’ review indicates that the reported effects of walnuts on glycaemic control have been inconclusive, with several studies showing association with improved glycaemic control while others show no effect. Despite their high energy density and potential to contribute to weight gain, the authors’ review suggests that walnuts can contribute to satiety without association with weight gain. This review also suggests that walnut consumption has been associated with improved low-density lipoprotein cholesterol levels and endothelial function but has not been associated with blood pressure improvement. Meta-analyses are warranted to quantitatively assess impact of walnut consumption on these cardio-metabolic risk factors in T2DM.

Inulin-type fructans supplementation improves glycemic control for the prediabetes and type 2 diabetes populations: results from a GRADE-assessed systematic review and dose-response meta-analysis of 33 randomized controlled trials

Background

Currently, many clinical trials have shown that inulin-type fructans (ITF) supplementation is associated with glycemic control; nevertheless, the results are inconclusive. The aim of this meta-analysis of randomized controlled trials was to assess the effects of ITF supplementation on glycemic control.

Methods

PubMed, EMBASE and the Cochrane Library were searched for eligible articles up to March 6, 2019. A random-effects model was used to analyze the pooled results, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was applied to assess the quality of evidence. The dose–response model was used to recommend the daily dose and duration for ITF supplementation.

Results

Thirty-three trials involving 1346 participants were included. Overall, ITF supplementation could significantly reduce concentrations of fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), fasting insulin (FINS) and homeostasis model assessment-insulin resistance (HOMA-IR). In the prediabetes and type 2 diabetes (T2DM) population, a more significant reduction in FBG [weighted mean difference (WMD): − 0.60 mmol/l; 95% CI − 0.71, − 0.48 mmol/l; high rate], HbA1c (WMD: − 0.58%; 95% CI − 0.83, − 0.32%; high rate), FINS (WMD: − 1.75 µU/ml; 95% CI − 2.87, − 0.63 µU/ml; low rate), and HOMA-IR (WMD: − 0.69; 95% CI − 1.10, − 0.28; low rate) were observed, and ITF supplementation with a daily dose of 10 g for a duration of 6 weeks and longer was recommended. Moreover, subgroup analyses suggested that the effects of glycemic control were significantly influenced by the sex of the subjects and the type and the method of intake of ITF.

Conclusions

Our analyses confirmed that these four main glycemic indicators were significantly reduced by ITF supplementation, particularly in the prediabetes and T2DM population. Evidence supports that reasonable administration of ITF supplementation may have potential clinical value as an adjuvant therapy for prediabetes and T2DM management.

Trial registration The trial was registered at PROSPERO as CRD42018115875 on November 23, 2018.

High-Protein Diets for Treatment of Type 2 Diabetes Mellitus: A Systematic Review

Diet has the potential to be a powerful and cost-effective tool for treatment of type 2 diabetes mellitus (T2D). High-protein diets have shown promise for this purpose. The objective of this systematic review was to evaluate whether high-protein diets improve glycemic outcomes in people with T2D. We conducted a systematic search of literature published prior to 1 February 2018 to find clinical studies of high-protein diet patterns for treatment of T2D in human participants. A high-protein diet was defined as a diet with protein content greater than that of a typical diet in the United States (>16% of total energy as protein). Studies were excluded if weight loss >5% occurred or if no glycemic outcomes were measured. A total of 21 independent articles met our criteria and were included. Most tested diets had a protein content of around 30% of total energy. Many studies supported the use of high-protein diets for patients with T2D, but were limited by small size (n = 8-32) and short duration (1-24 wk). Randomized controlled trials tended to be larger (n = 12-419) and longer (6 wk-2 y), and had mixed results, with many trials showing no difference between a high-protein diet and control. Many randomized controlled trials were limited by low compliance and high dropout rates >15%. There were no consistent beneficial or detrimental effects of high-protein diets on renal or cardiovascular outcomes. Evidence was insufficient to recommend 1 type of protein (plant or animal) over the other. Our review suggests that interventions to improve compliance with diet change over the long term may be equally important as specific macronutrient recommendations for treatment of T2D.

Dietary source of saturated fat and percentage body fat of patients with type 2 diabetes mellitus: A cross-sectional study

BACKGROUND

The influence of dietary fat on the body fat of patients with diabetes is not well established. This cross-sectional study aimed to analyze the association between percentage body fat (PBF) and dietary sources of fat from the usual diet of patients with type 2 diabetes.

METHODS

Outpatients were submitted to PBF evaluation estimated by bioelectrical impedance. The patient's usual diet was assessed by a 3-day weighed diet record (WDR), and compliance was analyzed by comparing the protein intake estimated from the WDR and that from 24-hr urinary nitrogen output.

RESULTS

A total of 188 patients with type 2 diabetes (aged 62.5 ± 8.8 years; 57% female, body mass index [BMI] 29.3 ± 3.8 kg/m²) were analyzed and divided into groups with high and low PBF according to mean PBF (men: 26.6 ± 7.1%; women: 39.8 ± 5.9%). Patients with high PBF consumed an increased proportion of red meat (52.0% of total meat), processed meat (5.4%), and saturated fat from red meat (2.1% of energy) compared to low PBF individuals (42.3% [p = 0.036]; 3.0% [p = 0.010]; 1.5% of energy [p = 0.032], respectively). According to Poisson's regression, the consumption of red meat (PR = 1.008 [95% CI = 1.002-1.013]; p = 0.006) and the reuse of frying oil (PR = 1.670 [95% CI = 1.240-2.249]; p = 0.001) were associated with higher PBF. In the adjusted analysis, the upper tertile of processed meat intake was associated with higher PBF (PR = 1.522 [95% CI = 1.226-1.891]; p = 0.001) compared to the lower tertile.

CONCLUSIONS

The present study suggested that a higher ingestion of dietary sources of saturated fat was associated with high PBF in patients with type 2 diabetes.

Influence of Probiotics Administration on Gut Microbiota Core: A Review on the Effects on Appetite Control, Glucose, and Lipid Metabolism

An increasing number of studies has shown that dietary probiotics exert beneficial health effects in both humans and animals. It is well established that gut microbiota play a pivotal role in regulating host metabolism, and a growing number of studies has elucidated that probiotics positively interfere with gut microbiota. Accumulating evidence shows that probiotics, through their metabolic activity, produce metabolites that in turn contribute to positively affect host physiology. For these reasons, probiotics have shown significant potential as a therapeutic tool for a diversity of diseases, but the mechanisms through which probiotics act has not been fully elucidated yet. The goal of this review was to provide evidence on the effects of probiotics on gut microbiota changes associated with host metabolic variations, specifically focusing on feed intake and lipid and glucose metabolism. In addition, we review probiotic interaction with the gut microbiota. The information collected here will give further insight into the effects of probiotics on the gut microbiota and their action on metabolite release, energy metabolism, and appetite. This information will help to improve knowledge to find better probiotic therapeutic strategies for obesity and eating disorders.

A review and critique of published real-world weight management program studies

BACKGROUND

Beyond the essential but somewhat artificial conditions that typify formal clinical studies, real-world evidence (RWE) of weight loss program effectiveness is paramount for an accurate assessment of such programs and refinement of best practices.

OBJECTIVES

To evaluate the current state of RWE studies and publications on weight loss, identify the range of weight loss components being used in RWE programs, and to provide a general overview of the consistency or lack of consistency with regard to measuring and reporting outcomes.

METHODS

A structured search of PubMed was performed to identify relevant English-language publications from 2006 to December 2017 that reported real-world studies of weight loss among adults. Duplicates, non-relevant publications, articles on weight loss surgery, pediatric studies, randomized controlled trials, studies with self-reported weight loss, no objective weight measures, or that failed to include weight loss results were excluded.

RESULTS

This review included 62 RWE publications. Forty-nine studies included dietary intervention, 37 included exercise, 29 included motivational counseling, and 5 contained some patients who had pharmacologic treatment as part of their weight loss regimen. The numbers of participants per study ranged from 10 to more than 3 million. The interventions reported in the publications included diet, exercise, counseling to promote diet and/or exercise, motivational counseling, and pharmacotherapy, and various combinations of these.

CONCLUSIONS

Despite general acceptance that weight loss programs are capable of facilitating successful outcomes, this review revealed substantial inconsistency in the design and reporting of such programs, making it very difficult to draw conclusions about the comparative merits of different real-world weight loss strategies/components. In addition, there was a marked lack of congruence with current weight loss management guidelines, and notably few studies incorporating anti-obesity medications. There clearly is a need for greater rigor and standardization among designing and reporting RWE weight-loss studies.

The Resulting Variation in Nutrient Intake With the Inclusion of Walnuts in the Diets of Adults at Risk for Type 2 Diabetes: A Randomized, Controlled, Crossover Trial

PURPOSE

We previously demonstrated that including walnuts in the diets of adults at risk for type 2 diabetes mellitus (T2DM) led to improved overall diet quality. This report examines the specific changes in their nutrient intake.

DESIGN

This was a randomized, controlled, modified Latin square parallel design trial with 2 treatment arms. Participants were randomized to walnut intake with, or without, dietary advice to regulate caloric intake. Within each treatment arm, they were further randomized to one of 2 sequence permutations (walnut-included/walnut-excluded or walnut-excluded/walnut-included diet), with a 3-month washout between treatment phases.

SETTING

Community hospital in Lower Naugatuck Valley in Connecticut.

PARTICIPANTS

Cohort of 112 participants (31 men and 81 women) at risk for T2DM.

INTERVENTION

Participants included 56 g (366 kcal) of walnuts in their daily diets for 6 months.

MEASURES

Nutrient intake was assessed using web-based Automated Self-Administered 24-Hour Dietary Assessment.

ANALYSIS

Data were analyzed using generalized linear models.

RESULTS

Walnut inclusion led to increased intake of total fat, calcium, magnesium, thiamin, total saturated fatty acids, and monounsaturated and polyunsaturated fatty acids (379.0 ± 90.3 g vs -136.5 ± 92.7 g, P < .01; 230.7 ± 114.2 mg vs -95.2 ± 117.4 mg, P = .05; 111.0 ± 33.9 mg vs -32.3 ± 34.9 mg, P < .01; 0.28 ± 0.2 mg vs -0.47 ± 0.2 mg, P = .02; 8.6 ± 3.4 g vs -1.1 ± 3.5 g, P =.05; 6.3 ± 3.9 g vs -6.3 ± 4.0 g, P = .03; and 25.4 ± 4.0 vs -6.6 ± 4.2 g, P < .01, respectively). Vitamin C intake decreased (-65.3 ± 55.3 mg vs 98.9 ± 56.8 mg, P = .04). Protein intake increased from baseline with the inclusion of walnuts (20.0 ± 8.8 g, P < .05). Walnut inclusion led to an increase in total calories consumed when caloric intake is not regulated.

CONCLUSION

Including walnuts in the diets of these adults led to increased dietary intake of some nutrients associated with lower risk of developing T2DM and other cardiometabolic risk factors.

Effects of high EPA and high DHA fish oils on changes in signaling associated with protein metabolism induced by hindlimb suspension in rats

The effects of either eicosapentaenoic (EPA)- or docosahexaenoic (DHA)-rich fish oils on hindlimb suspension (HS)-induced muscle disuse atrophy were compared. Daily oral supplementations (0.3 mL/100 g b.w.) with mineral oil (MO) or high EPA or high DHA fish oils were performed in adult rats. After 2 weeks, the animals were subjected to HS for further 2 weeks. The treatments were maintained alongside HS At the end of 4 weeks, we evaluated: body weight gain, muscle mass and fat depots, composition of fatty acids, cross-sectional areas (CSA) of the soleus muscle and soleus muscle fibers, activities of cathepsin L and 26S proteasome, and content of carbonylated proteins in the soleus muscle. Signaling pathway activities associated with protein synthesis (Akt, p70S6K, S6, 4EBP1, and GSK3-beta) and protein degradation (atrogin-1/MAFbx, and MuRF1) were evaluated. HS decreased muscle mass, CSA of soleus muscle and soleus muscle fibers, and altered signaling associated with protein synthesis (decreased) and protein degradation (increased). The treatment with either fish oil decreased the ratio of omega-6/omega-3 fatty acids and changed protein synthesis-associated signaling. EPA-rich fish oil attenuated the changes induced by HS on 26S proteasome activity, CSA of soleus muscle fibers, and levels of p-Akt, total p70S6K, p-p70S6K/total p70S6K, p-4EBP1, p-GSK3-beta, p-ERK2, and total ERK 1/2 proteins. DHA-rich fish oil attenuated the changes induced by HS on p-4EBP1 and total ERK1 levels. The effects of EPA-rich fish oil on protein synthesis signaling were more pronounced. Both EPA- and DHA-rich fish oils did not impact skeletal muscle mass loss induced by non-inflammatory HS.

The effects of n-3 long-chain polyunsaturated fatty acid supplementation on AGEs and sRAGE in type 2 diabetes mellitus

In diabetes mellitus, chronic hyperglycemia leads to formation of advanced glycation end products (AGEs). Binding of AGEs to receptors of AGE (RAGE) causes deleterious effects. In populations with a high consumption of n-3 long-chain polyunsaturated fatty acids, a lower prevalence of diabetes mellitus has been reported. We aimed to investigate the effects of n-3 fatty acid (EPA and DHA) supplementation on the levels of AGEs (carboxymethyl lysine (CML) and pentosidine), sRAGE, and nuclear factor kappa B (NF-kB) in type 2 diabetes mellitus (T2DM). T2DM patients (n = 38) treated with oral hypoglycemic agents, without insulin were supplemented with n-3 fatty acids (1.2 g/day) for 2 months. Plasma CML, pentosidine, sRAGE, and NF-kB levels were measured by ELISA both before and after the supplementation. n-3 fatty acid supplementation significantly reduced fasting glucose (p < 0.01), glycated hemoglobin (HbA_1c) (p < 0.05), and pentosidine (p < 0.05) levels. The supplementation induced percentage changes in pentosidine and HbA_1c and in pentosidine and creatinine were observed to be correlated (r = 0.349, p < 0.05) and (r = 0.377, p < 0.05), respectively. Waist circumference and systolic and diastolic pressures were significantly decreased due to n-3 supplementation (p < 0.001, p < 0.01, p < 0.01), respectively. Our results show that supplementation with n-3 fatty acid has beneficial effects on waist circumference; systolic and diastolic blood pressures; and the levels of glucose, HbA_1c, and pentosidine in T2DM patients. However, the supplementation failed to decrease these parameters to the reference ranges for healthy subjects. In addition, the supplementation did not appear to induce any significant differences in CML, sRAGE, or NF-kB.

The ZONE Diet and Metabolic Control in Type 2 Diabetes

Obesity is associated with chronic inflammation of the adipose tissue, which contributes to obesity-associated complications such as insulin resistance and type 2 diabetes. The increased inflammatory response seems to be directly related to modern nutrition, particularly aspects of fat quality and macronutrient composition. We have recently published an observational study investigating the practicability and effects of a combined dietary intervention with increased relative protein content and low-glycemic-index carbohydrates, supplemented with omega-3 polyunsaturated fatty acids (PUFAs), on metabolic control and inflammatory parameters in real-life situations in patients with type 2 diabetes. The primary efficacy parameter was the change in HbA1c, and secondary parameters included change in systemic inflammation (measured by ultrasensitive C-reactive protein), body weight, waist circumference, fat mass, and homeostasis model assessment-insulin resistance. Counseling a protein-enriched and low-glycemic-index diet supplemented with long-chain omega-3 PUFAs in a real-life clinical setting improved glycemic control, waist circumference, and silent inflammation in overweight or obese patients with type 2 diabetes.

Effect of Probiotics on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

BACKGROUND

Previous clinical trials indicate that probiotic consumption may improve blood glucose control, however, results from randomized trials on glycemic control have been inconsistent.

OBJECTIVE

To investigate the effects of probiotics on glycemic control in a systematic review and meta-analysis of randomized controlled trials.

DATA SOURCES

PubMed, Embase, Cochrane Library, and Clinicaltrial.gov through October 2014.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted relevant data and assessed study quality and risk of bias. Data were pooled using a random-effects model and expressed as mean differences (MD) with 95% CI. Heterogeneity was assessed (Cochran Q-statistic) and quantified (I2).

RESULTS

Seventeen randomized controlled trials were included, in which 17 fasting blood glucose (n = 1105), 11 fasting plasma insulin (n = 788), 8 homeostasis model assessment of insulin resistance (n = 635) comparisons were reported. Probiotic consumption, compared with placebo, significantly reduced fasting glucose (MD = -0.31 mmol/L; 95% CI 0.56, 0.06; p = 0.02), fasting plasma insulin (MD = -1.29 μU/mL; 95% CI -2.17, -0.41; p = 0.004), and HOMA-IR (MD = 0.48; 95% CI -0.83, -0.13; p = 0.007).

CONCLUSIONS

Probiotic consumption may improve glycemic control modestly. Modification of gut microbiota by probiotic supplementation may be a method for preventing and control hyperglycemia in clinical practice.

Chemoprotective epigenetic mechanisms in a colorectal cancer model: Modulation by n-3 PUFA in combination with fermentable fiber

Colorectal cancer is the third major cause of cancer-related mortality in both men and women worldwide. The beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing colon cancer is substantiated by experimental, epidemiological, and clinical data. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely modulates membrane and nuclear receptors, sensors/ion channels, and membrane structure/cytoskeletal function, thereby regulating signaling processes that influence patterns of gene expression and cell phenotype. In addition, n-3 PUFA can synergize with other potential chemoprotective agents known to reprogram the chromatin landscape, such as the fermentable fiber product, butyrate. Nutri-epigenomics is an emerging field of research that is focused on the interaction between nutrition and epigenetics. Epigenetics refers to a group of heterogeneous processes that regulate transcription without changing the DNA coding sequence, ranging from DNA methylation, to histone tail modifications and transcription factor activity. One implication of the nutri-epigenome is that it may be possible to reprogram epigenetic marks that are associated with increased disease risk by nutritional or lifestyle interventions. This review will focus on the nutri-epigenomic role of n-3 PUFA, particularly DHA, as well as the combinatorial effects of n-3 PUFA and fermentable fiber in relation to colon cancer.

Effects of a Macro-Nutrient Preload on Type 2 Diabetic Patients

AIMS

Macro-nutrient preloads given 30 min before regular meals may improve metabolism. The aim was to investigate how type 2 diabetic patients react to a preload consisting of a blend of macro-nutrients with a low-glycemic index (Inzone Preload(®)).

METHODS

In a before-after study design, 30 subjects with type 2 diabetes mellitus (T2DM) were enrolled in a 12-week program. All subjects were given Inzone Preload (43% proteins, 29% carbohydrates, 10% lipids, and 9% fibers, 71 kcal), 30 min before each meal during 12 weeks. Fasting glucose and postprandial 2 h glucose were monitored every second week. Body weight (BW) and waist circumference were measured each month. Fasting plasma glucose, glycosylated hemoglobin, serum lipids, fasting insulin, C-reactive protein, and homeostasis model assessment were evaluated before and after the intervention. Subjective appetite was monitored using visual analogue scales after the Inzone Preload.

RESULTS

The dietary intervention significantly influenced several metabolic parameters compared to base line. Inzone Preload treatment reduced mean postprandial plasma glucose levels (12.2 ± 1.2 vs. 10.5 ± 2.0 mmol/L), HbA1c (7.4 ± 0.3 vs. 7.1 ± 0.2%), mean total cholesterol (4.8 ± 0.9 vs. 4.3 ± 0.8 mmol/L), low-density lipoprotein cholesterol (2.8 ± 0.6 vs. 2.5 ± 0.4 mmol/L), and CRP (1.5 ± 1.4 vs. 0.7 ± 0.7 mg/L). BW loss of more than 3% was seen in 13 participants (43%). Feelings of satiety were significantly higher after Inzone Preload than after habitual breakfast (p < 0.05). No significant changes in fasting blood glucose, high-density lipoprotein and total triacylglycerol, HOMA-IR, and HOMA-β were observed.

CONCLUSION

A macro-nutrient preload treatment reduces postprandial glucose, inflammatory markers, and serum lipids in patients with T2DM. Approximately half of the study group also displayed reduced BW.