Polyunsaturated Fatty Acids and Glycemic Control in Type 2 Diabetes

Development and application of a sensitive liquid chromatography-tandem mass spectrometry method for the quantitative analysis of 11 free fatty acids in human serum using a derivatisation strategy

A stable isotope dilution-liquid chromatography-tandem mass spectrometry method based on a derivatisation strategy involving an N,N'-carbonylimidazole solution (CDI) with 4-(dimethylamino)-benzenemethanamine was developed for the determination of 11 free fatty acids (FFAs) in human blood samples. Serum samples were subjected to liquid‒liquid extraction and centrifuged, and the supernatant was collected for a two-step derivatisation reaction with a CDI and 4-(dimethylamino)-aniline acetonitrile solution. The derivatised solution was separated on a ACQUITY UPLC HSS T3 column (2.1 × 50 mm, 1.8 µm) column with a mobile phase consisting of water-acetonitrile in gradient elution and then detected by tandem mass spectrometry using electrospray ionisation (ESI) and multiple reaction monitoring (MRM) in positive ion mode and quantified using the isotope internal standard method. The effects of the derivatisation reaction time, temperature and concentration of derivatisation reagents on the response values of the analytes were investigated. The optimal conditions were as follows: 1.0 mg mL-1 CDI acetonitrile solution at 25 °C for 25 min, followed by a reaction with a 1.0 mg mL-1 4-(dimethylamino)-benzenemethanamine acetonitrile solution at 70 °C for 30 min. Under the optimal conditions, the limits of detection (LODs) of the 11 FFAs were in the range of 3.0-14.0 ng mL-1; the limits of quantification (LOQs) were in the range of 8.0-45.0 ng mL-1; and the mean recoveries ranged from 83.4 to 112.8%, with intraday and interday precisions ranging from 0.7 to 9.1% and 3.7-9.5%, respectively. The experimental method is simple in terms of the pretreatment operation, accurate and reliable, and can be applied to the sensitive determination of FFAs in human blood samples.

The Role of Omega- 3 Polyunsaturated Fatty Acids in Diabetes Mellitus Management: A Narrative Review

PURPOSE OF REVIEW

Diabetes mellitus (DM) is a group of metabolic illnesses characterized by elevated levels of glucose in the bloodstream as a result of abnormalities in the generation or function of insulin. Medical Nutrition Therapy (MNT) is an essential component of diabetes management. Dietary fats are essential in both the prevention and progression of chronic diseases. Omega-3 polyunsaturated fatty acids are recognized for their advantageous impact on health. They assist in controlling blood sugar levels and lipid profile in patients with all types of diabetes. Furthermore, they reduce the occurrence of cardiovascular events and death linked to DM.

RECENT FINDINGS

After evaluating the antioxidant, anti-inflammatory, antilipidemic, and antidiabetic mechanisms of omega-3 fatty acid supplements, as well as the results from randomized controlled studies, it is clear that these supplements have positive effects in both preventing and treating diabetes, as well as preventing and treating complications related to diabetes, specifically cardiovascular diseases. However, current evidence does not support the use of omega-3 supplementation in people with diabetes for the purpose of preventing or treating cardiovascular events. People with all types of diabetes are suggested to include fatty fish and foods high in omega-3 fatty acids in their diet twice a week, as is prescribed for the general population.

Association between circulating levels of unsaturated fatty acids and risk for prediabetes in the NHANES 2003-2004 and 2011-2012

AIMS

This study aimed to investigate the association between serum levels of common and uncommon unsaturated fatty acids and prediabetes risk.

METHODS

Data were collected from the National Health and Nutrition Examination Survey for 2003-2004 and 2011-2012. Weighted proportional and multivariate logistic regression analyses were performed to assess the association of serum PUFAs and MUFAs with prediabetes risk after adjusting for potential confounders.

RESULTS

A total of 3575 individuals were enrolled in this study. Serum levels of PUFAs EPA (20:5 n3) and GLA (18:3 n6) were associated with increased prediabetes risk (EPA (20:5 n3): OR = 1.878, 95% CI: 1.177-2.996, Ptrend = 0.002; GLA (18:3 n6): 1.702, 95% CI: 1.140-2.541, Ptrend = 0.016). The MUFAs PA (16:1 n7) and EA (20:1 n9) were associated with the risk of prediabetes (OR in quintile5: PA (16:1 n7): 1.780, 95% CI: 1.056-3.001, Ptrend = 0.003; EA (20:1 n9): 0.587, 95% CI: 0.347-0.994, Ptrend = 0.010). Moreover, nonlinear analysis revealed that serum levels of EPA (20:5 n3) and EA (20:1 n-9) were nonlinearly associated with prediabetes risk.

CONCLUSION

Some serum n-3 PUFAs are positively associated with prediabetes, several serum n-6 PUFAs are inversely associated with prediabetes. Regulating individual serum USFA levels may help prevent prediabetes, thereby providing evidence for clinical and nutritional practices.

The benefits of flushing with Lemuru fish oil as a source of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on the performance of reproductive parameters in Garut ewes

This study aimed to evaluate and analyze the effects of a flushing diet containing Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) from Lemuru (Sardinella sp) fish oil on the reproductive performance parameters of Garut ewes. Forty (n = 40) primiparous Garut ewes aged 12-14 months with an average body weight of 28.92 ± 4.94 kg were assigned into four experimental treatment groups. The experimental diets contained roughage: concentrate (30:70%) designated as control concentrate (CNT), flushing concentrate with 6% palm oil (PO), flushing concentrate with 3% palm oil mixed with 3% lemuru oil as DHA and EPA sources (PFO), and flushing concentrate with the addition of 6% lemuru oil (FO). Treatment animals were fed two weeks before and after conception and parturition (8 weeks of total flushing treatment). The addition of fish oil at either 3% (PFO) or 6% (FO) resulted in significantly higher reproductive performance of ewes by increasing the litter size, as reflected by the birth of multiple kids (P < 0.05) compared to CNT and PO. Adding fish oil (PFO and FO) also maintains gestation, resulting in increased lamb yield, especially in the FO treatment, which yields the highest lamb yield (0% single lamb birth). The lamb male ratio was also higher with fish oil supplementation (PFO and PO) (P < 0.05). This research revealed a positive effect of 6% Lemuru oil on decreasing embryo loss and increasing the proportion of twin births. These findings thus support the hypothesis that ration flushing with double the required DHA and EPA from 6% Lemuru fish oil (FO) resulted in significantly higher reproductive performance in Garut sheep.

Association of birth weight with type 2 diabetes mellitus and the mediating role of fatty acids traits: a two-step mendelian randomization study

BACKGROUND

Observational studies have suggested an association between birth weight and type 2 diabetes mellitus, but the causality between them has not been established. We aimed to obtain the causal relationship between birth weight with T2DM and quantify the mediating effects of potential modifiable risk factors.

METHODS

Two-step, two-sample Mendelian randomization (MR) techniques were applied using SNPs as genetic instruments for exposure and mediators. Summary data from genome-wide association studies (GWAS) for birth weight, T2DM, and a series of fatty acids traits and their ratios were leveraged. The inverse variance weighted (IVW) method was the main analysis approach. In addition, the heterogeneity test, horizontal pleiotropy test, Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) test, and leave-one-out analysis were carried out to assess the robustness.

RESULTS

The IVW method showed that lower birth weight raised the risk of T2DM (β: -1.113, 95% CI: -1.573 ∼ -0.652). Two-step MR identified 4 of 17 candidate mediators partially mediating the effect of lower birth weight on T2DM, including ratio of polyunsaturated fatty acids to monounsaturated fatty acids (proportion mediated: 7.9%), ratio of polyunsaturated fatty acids to total fatty acids (7.2%), ratio of omega-6 fatty acids to total fatty acids (8.1%) and ratio of linoleic acid to total fatty acids ratio (6.0%).

CONCLUSIONS

Our findings supported a potentially causal effect of birth weight against T2DM with considerable mediation by modifiable risk factors. Interventions that target these factors have the potential to reduce the burden of T2DM attributable to low birth weight.

Enzymatic synthesis and characterization of novel lipophilic inotodiol-oleic acid conjugates

In this study, we establish an efficient enzymatic approach for producing novel inotodiyl-oleates (IOs) from pure inotodiol and oleic acid to improve the properties of inotodiol. For the esterification between inotodiol and oleic acid, CALA and n-hexane were the optimal biocatalyst and solvents for forming IOs with 80.17% conversion yield. These IOs comprised two distinct monoesters, the C3 or C22 ester forms of inotodiol. Intriguingly, no diesters were detected. The IOs had a melting point of 53.48 °C, much lower than that of inotodiol (192.06 °C). The in vitro digestion rate of IOs (25-28%) was significantly (p < 0.05) lower than that of cholesteryl-oleate (60%). Additionally, IOs exhibited much lower in vivo absorption than inotodiol when orally administered using different formulations (p < 0.05). The results indicated that IOs were resistant to enzymatic digestion in the small intestine, which could be advantageous in targeting the large intestine for disease treatments.

Alzheimer's Disease in Diabetic Patients: A Lipidomic Prospect

Diabetes Mellitus (DM) and Alzheimer's disease (AD) have been two of the most common chronic diseases affecting people worldwide. Type 2 DM (T2DM) is a metabolic disease depicted by insulin resistance, dyslipidemia, and chronic hyperglycemia while AD is a neurodegenerative disease marked by Amyloid β (Aβ) accumulation, neurofibrillary tangles aggregation, and tau phosphorylation. Various clinical, epidemiological, and lipidomics studies have linked those diseases claiming shared pathological pathways raising the assumption that diabetic patients are at an increased risk of developing AD later in their lives. Insulin resistance is the tipping point beyond where advanced glycation end (AGE) products and free radicals are produced leading to oxidative stress and lipid peroxidation. Additionally, different types of lipids are playing a crucial role in the development and the relationship between those diseases. Lipidomics, an analysis of lipid structure, formation, and interactions, evidently exhibits these lipid changes and their direct and indirect effect on Aβ synthesis, insulin resistance, oxidative stress, and neuroinflammation. In this review, we have discussed the pathophysiology of T2DM and AD, the interconnecting pathological pathways they share, and the lipidomics where different lipids such as cholesterol, phospholipids, sphingolipids, and sulfolipids contribute to the underlying features of both diseases. Understanding their role can be beneficial for diagnostic purposes or introducing new drugs to counter AD.

Effect of sesame (Sesamum indicum L.) consumption on glycemic control in patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

Conflicting evidence exists on the effect of sesame consumption on glucose metabolism in patients with type 2 diabetes (T2D). Therefore, this meta-analysis focuses on the relationship between sesame (Sesamum indicum L.) intervention and glycemic control in patients with T2D. Published literature was retrieved and screened from PubMed, Scopus, ISI Web of Science, and the Cochrane Library up to December 2022. Outcome measures included fasting blood sugar (FBS) concentrations, fasting insulin levels, and hemoglobin A1c (HbA1c) percentage. Pooled effect sizes were reported as weighted mean differences (WMDs) and 95% confidence intervals (CIs). Eight clinical trials (395 participants) were eligible for meta-analyses. Overall, sesame consumption significantly reduced serum FBS (WMD: -28.61 mg/dL, 95% CI: -36.07 to -21.16, p˂0.001; I2  = 98.3%) and HbA1c percentage (WMD: -0.99%, 95% CI: -1.22 to -0.76, p ≤ 0.001; I2  = 65.1%) in patients with T2D. However, sesame consumption did not significantly influence fasting insulin levels (Hedges's: 2.29, 95% CI: -0.06 to 4.63, p = 0.06; I2  = 98.1%). In summary, the current meta-analysis showed a promising effect of sesame consumption on glycemic control through reducing FBS and HbA1c, yet additional prospective studies are recommended, using higher doses and longer intervention period, to confirm the impact of sesame consumption on insulin levels in T2D patients.

Characterization of serum polyunsaturated fatty acid profile in patients with inflammatory bowel disease

Background:

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the digestive tract. The aetiology and pathogenesis of IBD are complex, which may lead to metabolic disorders. As a kind of metabolite, polyunsaturated fatty acid (PUFA) is closely related to IBD.

Objectives:

The aim of this study was to explore the correlation between the serum PUFAs and the pathogenesis of IBD.

Design:

The study is a hospital-based case-control study.

Methods:

The serum free PUFAs of all participants, including 104 patients with IBD and 101 normal controls, were detected by liquid chromatography–mass spectrometry (LC-MS).

Results:

Compared with the normal control, the levels of C18:2, α-C18:3 (ALA), ɤ-C18:3, C20:4 (AA), C20:5 (EPA), ω-3 C22:5, ω-6 C22:5 and C22:6 (DHA) PUFAs in patients with Crohn’s disease (CD) were obviously decreased. However, in patients with ulcerative colitis (UC), the levels of AA, EPA, ω-3 C22:5, ω-6 C22:5 and DHA were downregulated. The concentrations of seven PUFAs were significantly downregulated in the active CD group. In addition, four PUFAs had comparatively higher levels in the remission UC group.

Conclusion:

The present study revealed substantial differences in the levels of serum fatty acids between normal controls and patients with IBD. In detail, patients with CD were deficient in PUFAs, including the essential fatty acids. Moreover, as the disease activity aggravated, some PUFAs decreased dramatically.

Is dietary intake of antioxidant vitamins associated with reduced adverse effects of air pollution on diabetes? Findings from a large cohort study

INTRODUCTION

It remains unknown whether higher dietary intake of antioxidant vitamins could reduce the harmful effects of air pollution on incident diabetes mellitus.

METHODS

A total of 156,490 participants free of diabetes mellitus in the UK Biobank data were included in this analysis. Antioxidant vitamin intake was measured using a 24-h food intake questionnaire, and results were categorized as sufficient or insufficient according to the British Recommended Nutrient Intake. Exposure to fine particles (PM_2.5), thoracic particles (PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxide (NO_x) was estimated using land use regression models at participants' residences. Incident diabetes mellitus was identified using health administrative datasets. Cox regression models were used to assess the associations.

RESULTS

A total of 4271 incident diabetes mellitus cases were identified during a median follow-up of 11.7 years. Compared with participants with insufficient intake of antioxidant vitamins, those with sufficient consumption had a weaker association between air pollution (PM_2.5, PM₁₀ and NO₂) and diabetes mellitus [sufficient vs. insufficient: HR = 1.12 (95 % CI: 0.87, 1.45) vs. 1.69 (95 % CI: 1.42, 2.02) for PM_2.5, 1.00 (95 % CI: 0.88, 1.14) vs. 1.21 (95 % CI: 1.10, 1.34) for PM₁₀, and 1.01 (95 % CI: 0.98, 1.04) vs. 1.05 (95 % CI: 1.03, 1.07) for NO₂ (all p for comparison < 0.05)]. Among different antioxidant vitamins, we observed stronger effects for vitamin C and E.

CONCLUSION

Our study suggests that ambient air pollution is one important risk factor of diabetes mellitus, and sufficient intake of antioxidant vitamins may reduce such adverse effects of air pollution on diabetes mellitus.

Investigating the Role of EPA and DHA on Cellular Oxidative Stress; Profiling Antidiabetic and Antihypertensive Potential

Background

Polyunsaturated fatty acids (PUFAs) remain part of the diet and are essential for growth and development. Furthermore, omega - 3 fatty acids boost various cardiovascular disease risk factors as well as lower blood pressure and cholesterol levels. The effects of PUFAs on glycemia in type 2 diabetes patients are unclear. In the present study, the anti-diabetic and anti-hypertensive potential of eicosapentenoic acid (EPA) and docosahexaenoic acid (DHA)-two polyunsaturated fatty acids-were examined.

Material and Methods

Using 3T3-L1 pre-adipocyte cells fed with PUFAs, the antioxidant capacity of EPA and DHA was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay/test. The DPPH activity of EPA and DHA was 49.72 and 50.51%, respectively, indicating a reduction in oxidative stress. The number, size, and total lipid content of adipocytes in adipose tissue were used to study the anti-diabetic effect of EPA and DHA. Both PUFAs were revealed to have a much lower capacity for cell lysis of 3T3-L1 pre-adipocytes when compared to propylene glycol monomethyl ether acetate (PMA). In 3T3-L1 pre-adipocyte cells that had been treated with EPA and DHA, the gene expression profiles for ATP synthase 6 were examined.

Results

The results demonstrated a similar trend of reducing total lipid content in 3T3-L1 pre-adipocyte cells treated with EPA and DHA. The amount of cell lysis was then examined for 3T3-L1 pre-adipocyte cells exposed to DHA and EPA, and the results showed 38.45% and 41.26%, respectively. In the 3T3-L1 pre-adipocyte cells, treatment with PUFAs, EPA, and DHA dramatically lowered total lipid content after 48 hours. The study also revealed that exposing 3T3-L1 pre-adipocyte cells to EPA at 90 g/ml for 48 hours reduced the total lipid content by a significant amount.

Conclusion

According to the findings, EPA and DHA therapy reversed oxidative stress in mitochondria and upregulated the ATP synthase 6 gene. This discovery shows how EPA and DHA have anti-diabetic and hypertension properties.

In vivo antihyperglycaemic and antihyperlipidemic activities and chemical constituents of Solanum anomalum

Solanum anomalum is a plant used ethnomedically for the treatment of diabetes. The study was aimed to validate ethnomedical claims in rat model and identify the likely antidiabetic compounds. Leaf extract (70-210 mg/kg/day) and fractions (140 mg/kg/day) of S. anomalum were evaluated in hyperglycaemic rats induced using alloxan for effects on blood glucose, lipids and pancreas histology. Phytochemical characterisation of isolated compounds and their identification were performed using mass spectrometry and NMR spectroscopy. Bioinformatics tool was used to predict the possible protein targets of the identified bioactive compounds. The leaf extract/fractions on administration to diabetic rats caused significant lowering of fasting blood glucose of the diabetic rats during single dose study and on repeated administration of the extract. The hydroethanolic leaf extracts also enhanced glucose utilization capacity of the diabetic rats and caused significant lowering of glycosylated hemoglobin levels and elevation of insulin levels in the serum. Furthermore, triglycerides, LDL-cholesterol, and VLDL-cholesterol levels were lowered significantly, while HDL-cholesterol levels were also elevated in the treated diabetic rats. There was absence or few pathological signs in the treated hyperglycaemic rat pancreas compared to that present in the pancreas of control group. Diosgenin, 25(R)-diosgenin-3-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranoside, uracil, thymine, 1-octacosanol, and octacosane were isolated and identified. Protein phosphatases along with secreted proteins are predicted to be the major targets of diosgenin and the diosgenin glycoside. These results suggest that the leaf extract/fractions of S. anomalum possess antidiabetic and antihyperlipidemic properties, offer protection to the pancreas and stimulate insulin secretion, which can be attributable to the activities of its phytochemical constituents.

Dietary Fatty Acid Intake and the Colonic Gut Microbiota in Humans

A high-fat diet has been associated with systemic diseases in humans and alterations in gut microbiota in animal studies. However, the influence of dietary fatty acid intake on gut microbiota in humans has not been well studied. In this cross-sectional study, we examined the association between intake of total fatty acids (TFAs), saturated fatty acids (SFAs), trans fatty acids (TrFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), n3-FAs, and n6-FAs, and the community composition and structure of the adherent colonic gut microbiota. We obtained 97 colonic biopsies from 34 participants with endoscopically normal colons. Microbial DNA was used to sequence the 16S rRNA V4 region. The DADA2 and SILVA database were used for amplicon sequence variant assignment. Dietary data were collected using the Block food frequency questionnaire. The biodiversity and the relative abundance of the bacterial taxa by higher vs. lower fat intake were compared using the Mann−Whitney test followed by multivariable negative binomial regression model. False discovery rate−adjusted p-values (q value) < 0.05 indicated statistical significance. The beta diversity of gut bacteria differed significantly by intake of all types of fatty acids. The relative abundance of Sutterella was significantly higher with higher intake of TFAs, MUFAs, PUFAs, and n6-FAs. The relative abundance of Tyzzerella and Fusobacterium was significantly higher with higher intake of SFAs. Tyzzerella was also higher with higher intake of TrFA. These observations were confirmed by multivariate analyses. Dietary fat intake was associated with bacterial composition and structure. Sutterella, Fusobacterium, and Tyzzerella were associated with fatty acid intake.

Effects of common weight loss plans on diabetes mellitus and cardiovascular risk factors

Diabetes mellitus is globally considered one of the most common chronic diseases, management of which is critically asscociated with an adequate dietary approach. With overweight and obesity being a global epidemic, choosing the appropriate weight loss plan for patients with diabetes seems to be of particular concern for healthcare professionals. Since diabetes and cardiovascular diseases frequently coexist, modern pharmacological therapeutic models aim at addressing both. Therapeutic targets in diabetic population that address glycemic control, adequate lipid and blood pressure control proves to limit the incidence of cardiovascular events, reduce the risk of chronic complications and improve patients quality of life. Similarly, dietary managment in this population should also concentrate on the reduction of reversible cardiovascular risk factors. Nutritional recommendations for diabetic patients should be individualized to meet their expectations and lifestyle in order to ensure compliance and long-term effects. As diabetic population is more vulnerable to further health risks associated with diet induced metabolic changes, inadequate intake of dietary components and increased cardiovascular risk, nutrition plans should be addressed more carefully in this group.

CRISPR/Cas9-Mediated Knockout of miR-130b Affects Mono- and Polyunsaturated Fatty Acid Content via PPARG-PGC1α Axis in Goat Mammary Epithelial Cells

MicroRNA (miRNA)-130b, as a regulator of lipid metabolism in adipose and mammary gland tissues, is actively involved in lipogenesis, but its endogenous role in fatty acid synthesis remains unclear. Here, we aimed to explore the function and underlying mechanism of miR-130b in fatty acid synthesis using the CRISPR/Cas9 system in primary goat mammary epithelial cells (GMEC). A single clone with deletion of 43 nucleotides showed a significant decrease in miR-130b-5p and miR-130b-3p abundances and an increase of target genes PGC1α and PPARG. In addition, knockout of miR-130b promoted triacylglycerol (TAG) and cholesterol accumulation, and decreased the proportion of monounsaturated fatty acids (MUFA) C16:1, C18:1 and polyunsaturated fatty acids (PUFA) C18:2, C20:3, C20:4, C20:5, C22:6. Similarly, the abundance of fatty acid synthesis genes ACACA and FASN and transcription regulators SREBP1c and SREBP2 was elevated. Subsequently, interference with PPARG instead of PGC1α in knockout cells restored the effect of miR-130b knockout, suggesting that PPARG is responsible for miR-130b regulating fatty acid synthesis. Moreover, disrupting PPARG inhibits PGC1α transcription and translation. These results reveal that miR-130b directly targets the PPARG–PGC1α axis, to inhibit fatty acid synthesis in GMEC. In conclusion, miR-130b could be a potential molecular regulator for improving the beneficial fatty acids content in goat milk.

Omega-3 fatty acids coordinate glucose and lipid metabolism in diabetic patients

Omega 3 polyunsaturated fatty acids (n-3 PUFA) are known to have beneficial effects on cardiovascular and metabolic health. However, whether different sources of n-3 PUFA, for instance fatty fish vs vegetable oils, could elicit different effects on glucose and lipid metabolism, remains to be determined. Herein we examine recent findings showing that while a plant-based n-3 PUFA supplementation for six months can reduce fasting blood glucose, marine-based n-3 PUFA can instead reduce serum levels of triglycerides. We also discuss the potential molecular mechanisms that could underlie these different effects on the regulation of glycolipid metabolism.

Polyunsaturated fatty acid intake and incidence of type 2 diabetes in adults: a dose response meta-analysis of cohort studies

BACKGROUND

To evaluate the association and dose-response relationship between polyunsaturated fatty acid (PUFA) intake and incidence of type 2 diabetes (T2D) in adults.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched for cohort studies that examined the association between PUFA and T2D incidence published up to September 6, 2021. Relative risk (RR) or hazard ratio (HR) was used as the effect indicator, each effect size was expressed by 95% confidence interval (CI). The presence of heterogeneity of effect size between studies was assessed by the Q-test and I² statistics. If I² ≥ 50%, the random-effects model was applied, otherwise the fixed effects model was used. Sensitivity analysis was performed for all models. Potential publication bias was assessed. We conducted linear and nonlinear dose-response meta-analyses, calculated summary relative risk (SRR).

RESULTS

Twenty-five articles were selected including 54,000 patients in this study. Our estimates observed no linear associations between total PUFA and the incidence of T2D. However, the summary dose-response curve of T2D risk increased in a nonlinear pattern with the consumption of omega-3 PUFA (P_nonlinearity < 0.001) and docosahexaenoic acid (DHA) (P_nonlinearity = 0.040). Our subgroup analysis showed that total PUFA intake was associated with increased incidence of T2D in Europe (RR: 1.040, 95% CI 1.009 to 1.072), and Australia (RR: 1.188, 95% CI 1.113 to 1.269). However, total PUFA intake was associated with decreased T2D incidence in Asia (RR: 0.897, 95% CI 0.860 to 0.936). Subgroup analysis based on PUFA types showed that DHA intake was associated with decreased T2D incidence (RR: 1.164, 95% CI 1.048 to 1.294) while linoleic acid (LA) decreased T2D incidence (RR: 0.956, 95% CI 0.930 to 0.983). Regarding the sex subgroup, women's intake of total PUFA would increase the risk of T2D (RR: 1.049, 95% CI 1.019 to 1.079) while total PUFA intake decreased the risk of T2D in men (RR: 0.955, 95% CI 0.913 to 0.999).

CONCLUSION

For specific PUFA, dose-response curves show nonlinear significant associations between PUFA intakes and T2D. It may be necessary to pay attention to the effects of PUFA and type of intake on T2D. Trial registration Not applicable.

Diet and Physical Activity as Determinants of Continuously Measured Glucose Levels in Persons at High Risk of Type 2 Diabetes

We examined how dietary and physical activity behaviors influence fluctuations in blood glucose levels over a seven-day period in people at high risk for diabetes. Twenty-eight participants underwent a mixed meal tolerance test to assess glucose homeostasis at baseline. Subsequently, they wore an accelerometer to assess movement behaviors, recorded their dietary intakes through a mobile phone application, and wore a flash glucose monitoring device that measured glucose levels every 15 min for seven days. Generalized estimating equation models were used to assess the associations of metabolic and lifestyle risk factors with glycemic variability. Higher BMI, amount of body fat, and selected markers of hyperglycemia and insulin resistance from the meal tolerance test were associated with higher mean glucose levels during the seven days. Moderate- to vigorous-intensity physical activity and polyunsaturated fat intake were independently associated with less variation in glucose levels (CV%). Higher protein and polyunsaturated fatty acid intakes were associated with more time-in-range. In contrast, higher carbohydrate intake was associated with less time-in-range. Our findings suggest that dietary composition (a higher intake of polyunsaturated fat and protein and lower intake of carbohydrates) and moderate-to-vigorous physical activity may reduce fluctuations in glucose levels in persons at high risk of diabetes.

Integrated lipids biomarker of the prediabetes and type 2 diabetes mellitus Chinese patients

INTRODUCTION

Dyslipidemia is a hallmark of T2DM, and as such, analyses of lipid metabolic profiles in affected patients have the potential to permit the development of an integrated lipid metabolite-based biomarker model that can facilitate early patient diagnosis and treatment.

METHODS

Untargeted and targeted lipidomics approaches were used to analyze serum samples from newly diagnosed 93 Chinese participants in discovery cohort and 440 in validation cohort via UHPLC-MS and UHPLC-MS/MS first. The acid sphingomyelinase protein expression was analyzed by Western blot.

RESULTS AND DISCUSSION

Through these analyses, we developed a novel integrated biomarker signature composed of LPC 22:6, PC(16:0/20:4), PE(22:6/16:0), Cer(d18:1/24:0)/SM(d18:1/19:0), Cer(d18:1/24:0)/SM(d18:0/16:0), TG(18:1/18:2/18:2), TG(16:0/16:0/20:3), and TG(18:0/16:0/18:2). The area under the curve (AUC) values for this integrated biomarker signature for prediabetes and T2DM patients were 0.841 (cutoff: 0.565) and 0.894 (cutoff: 0.633), respectively. Furthermore, theresults of western blot analysis of frozen adipose tissue from 3 week (prediabetes) and 12 week (T2DM) Goto-Kakizaki (GK) rats also confirmed that acid sphingomyelinase is responsible for significant disruptions in ceramide and sphingomyelin homeostasis. Network analyses of the biomarkers associated with this biosignature suggested that the most profoundly affected lipid metabolism pathways in the context of diabetes include de novo ceramide synthesis, sphingomyelin metabolism, and additional pathways associated with phosphatidylcholine synthesis. Together, these results offer new biological insights regarding the role of serum lipids in the context of insidious T2DM development, and may offer new avenues for future diagnostic and/or therapeutic research.

Nutrients and Dietary Approaches in Patients with Type 2 Diabetes Mellitus and Cardiovascular Disease: A Narrative Review

Cardiovascular disease (CVD) is the most common cause of morbidity and mortality in developed countries. The prevalence of CVD is much higher in patients with type 2 diabetes mellitus (T2DM), who may benefit from lifestyle changes, which include adapted diets. In this review, we provide the role of different groups of nutrients in patients with T2DM and CVD, as well as dietary approaches that have been associated with better and worse outcomes in those patients. Many different diets and supplements have proved to be beneficial in T2DM and CVD, but further studies, guidelines, and dietary recommendations are particularly required for patients with both diseases.

Nutritional management of type 2 diabetes in subjects with obesity: an international guideline for clinical practice

Type 2 diabetes mellitus (T2DM) and obesity represent a global public health problem. Current nutritional recommendations focused on weight loss and overall dietary quality. However, there is no consensus on the optimal macronutrient composition of the diet, particularly for the long-term management of T2DM in subjects with obesity. An international panel of experts reviewed and critically appraised the updated literature published on the topic. This review primarily examines the evidence for areas of consensus and uncertainty about nutritional therapy in patients with T2DM and obesity. The aim of this article is to provide nutritional advice to manage these patients in clinical practice.

Association of plant-based diet and type 2 diabetes mellitus in Chinese rural adults: The Henan Rural Cohort Study

AIMS/INTRODUCTION

Studies have found that a plant-based diet was associated with a lower risk of type 2 diabetes, but evidence is scarce on such associations in China. The aim of this study was to investigate whether a plant-based diet is related to a lower risk of type 2 diabetes among Chinese adults.

MATERIALS AND METHODS

A total of 37,985 participants were enrolled from the Henan Rural Cohort Study. An overall plant-based diet index (PDI) was created by assigning positive and reverse scores to 12 commonly consumed food groups. Multivariate logistic regression models and restricted cubic spline analysis were performed to estimate the odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

After multivariable adjustment, the risk of type 2 diabetes was inversely associated with the PDI (extreme-quartile OR = 0.88, 95% CI: 0.79-0.98; P = 0.027), the risk associated with a 1 standard deviation (SD) increase in PDI was 4% lower (95% CI, 0.93-1.00; P trend  = 0.043) for type 2 diabetes. Moreover, the odds of type 2 diabetes was decreased with an increment of PDI after fitting restricted cubic splines (P trend  < 0.01).

CONCLUSIONS

Among Chinese populations, diets higher in plant foods and lower in animal foods were associated with a reduced risk of type 2 diabetes.

Manipulation of intestinal microbiome as potential treatment for insulin resistance and type 2 diabetes

PURPOSE

Increasing evidence suggests that the intestinal microbiome (IM) and bacterial metabolites may influence glucose homeostasis, energy expenditure and the intestinal barrier integrity and lead to the presence of systemic low-grade inflammation, all of which can contribute to insulin resistance (IR) and type 2 diabetes (T2D). The purpose of this review is to explore the role of the IM and bacterial metabolites in the pathogenesis and treatment of these conditions.

RESULTS

This review summarizes research focused on how to modulate the IM through diet, prebiotics, probiotics, synbiotics and fecal microbiota transplant in order to treat IR and T2D.

CONCLUSION

There is an abundance of evidence suggesting a role for IM in the pathogenesis of IR and T2D based on reviewed studies using various methods to modulate IM and metabolites. However, the results are inconsistent. Future research should further assess this relationship.

Effects of dietary eicosapentaenoic acid and docosahexaenoic acid supplementation on metabolic syndrome: A systematic review and meta-analysis of data from 33 randomized controlled trials

BACKGROUND & AIMS

Previous randomized controlled trials (RCTs) have compared the effects of pure preparations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in reducing metabolic syndrome (MetS) risk factors, but the results were inconsistent. The present study aimed to clarify whether EPA and DHA have differential effects on MetS features in humans.

METHODS

A systematic literature search was conducted in CNKI, PubMed, Embase and Scopus updated to February 2021. The mean changes in the characteristics of MetS were calculated as weighted mean differences by using a random-effects model. Thirty-three RCTs were included.

RESULTS

The results showed that both EPA and DHA were effective at lowering serum triglycerides (TG) levels. EPA supplementation decreased the serum levels of total cholesterol (TC) (WMD = -0.24 mmol/L; 95% CI, -0.43, -0.05 mmol/L), TG (WMD = -0.77 mmol/L; 95% CI, -1.54, -0.00 mmol/L) and low density lipoprotein-cholesterol (LDL-C) (WMD = -0.13 mmol/L; 95% CI, -0.25, -0.01 mmol/L), while DHA increased the serum levels of TC (WMD = 0.14 mmol/L; 95% CI, 0.03, 0.25 mmol/L), LDL-C (WMD = 0.26 mmol/L; 95% CI, 0.15, 0.38 mmol/L) and high density lipoprotein-cholesterol (HDL-C) (WMD = 0.07 mmol/L; 95% CI, 0.04, 0.09 mmol/L). Moreover, DHA increased the serum levels of insulin compared with EPA, especially in subgroups whose mean age was <60 years (0.43 mU/L; 95% CI: 0.04, 0.81 mU/L) and duration of DHA supplementation < 3 months (0.39 mU/L; 95% CI: 0.01, 0.77 mU/L).

CONCLUSIONS

The present meta-analysis provides evidence that EPA and DHA have different effects on risk factors of MetS.

The relationship between dietary exposure to persistent organic pollutants from fish consumption and type 2 diabetes among First Nations in Canada

OBJECTIVE

We previously examined the associations between dietary dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) intake from fish consumption and type 2 diabetes (T2D) prevalence in Ontario and Manitoba. This study aims to further explore the relationship in a regionally representative sample of First Nations adults living on-reserve across Canada.

METHODS

Dietary, health and lifestyle data collected by the cross-sectional First Nations Food, Nutrition and Environment Study (2008-2018) were analyzed. This participatory study included 6091 First Nations adult participants who answered questions on T2D. The consumption of locally caught fish was estimated with a food frequency questionnaire. A total of 551 samples from 96 fish species were collected and analyzed for the presence of DDE and PCBs. The associations between fish and dietary DDE/PCBs intake with self-reported T2D were investigated using multiple logistic regression models adjusted for confounders.

RESULTS

Dietary exposure to DDE (>2.11 ng/kg/bw) and PCBs (>1.47 ng/kg/bw) vs no exposure was positively associated with T2D with ORs of 2.33 (95% CI: 1.24-4.35) for DDE and 1.43 (95% CI: 1.01-3.59) for PCBs. The associations were stronger among females (DDE OR = 3.11 (1.41-6.88); PCBs OR = 1.76 (1.10-3.65)) and older individuals (DDE OR = 2.64 (1.12-6.20); PCBs OR = 1.44 (1.01-3.91)) as compared with males and younger participants. Also, significant dose-response relationships were found for fish consumption in females only.

CONCLUSION

This study confirms our previous findings that dietary DDE/PCBs exposure may increase the risk of T2D. The effect of DDE/PCBs from fish consumption is driven by geographical differences in DDE/PCBs concentrations in fish and by the amount of fish consumed, and is more prominent in females than in males.

Whole Alga, Algal Extracts, and Compounds as Ingredients of Functional Foods: Composition and Action Mechanism Relationships in the Prevention and Treatment of Type-2 Diabetes Mellitus

Type-2 diabetes mellitus (T2DM) is a major systemic disease which involves impaired pancreatic function and currently affects half a billion people worldwide. Diet is considered the cornerstone to reduce incidence and prevalence of this disease. Algae contains fiber, polyphenols, ω-3 PUFAs, and bioactive molecules with potential antidiabetic activity. This review delves into the applications of algae and their components in T2DM, as well as to ascertain the mechanism involved (e.g., glucose absorption, lipids metabolism, antioxidant properties, etc.). PubMed, and Google Scholar databases were used. Papers in which whole alga, algal extracts, or their isolated compounds were studied in in vitro conditions, T2DM experimental models, and humans were selected and discussed. This review also focuses on meat matrices or protein concentrate-based products in which different types of alga were included, aimed to modulate carbohydrate digestion and absorption, blood glucose, gastrointestinal neurohormones secretion, glycosylation products, and insulin resistance. As microbiota dysbiosis in T2DM and metabolic alterations in different organs are related, the review also delves on the effects of several bioactive algal compounds on the colon/microbiota-liver-pancreas-brain axis. As the responses to therapeutic diets vary dramatically among individuals due to genetic components, it seems a priority to identify major gene polymorphisms affecting potential positive effects of algal compounds on T2DM treatment.

Dietary and Protective Factors to Halt or Mitigate Progression of Autoimmunity, COVID-19 and Its Associated Metabolic Diseases

COVID-19 is without any doubt the worst pandemic we have faced since the H1N1 virus outbreak. Even if vaccination against SARS-CoV-2 infection is becoming increasingly available, a more feasible approach for COVID-19 prevention and therapy is still needed. Evidence of a pathological link between metabolic diseases and severe forms of COVID-19 has stimulated critical reflection and new considerations. In particular, an abnormal immune response observed in certain patients with SARS-CoV-2 infection suggested possible common predisposing risk factors with autoimmune diseases such as Type 1 Diabetes (T1D). Correct supplementation with dietary factors may be key to preventing and counteracting both the underlying metabolic impairment and the complications of COVID-19. A set of agents may inhibit the cytokine storm and hypercoagulability that characterize severe COVID-19 infection: vitamin D3, omega-3 polyunsaturated fatty acids, polyphenols like pterostilbene, polydatin and honokiol, which can activate anti-inflammatory and antioxidant sirtuins pathways, quercetin, vitamin C, zinc, melatonin, lactoferrin and glutathione. These agents could be highly beneficial for subjects who have altered immune responses. In this review, we discuss the antiviral and metabolic effects of these dietary factors and propose their combination for potential applications in the prevention and treatment of COVID-19. Rigorous studies will be fundamental for validating preventive and therapeutic protocols that could be of assistance to mitigate disease progression following SARS-CoV-2 infection.

How should we judge edible oils and fats? An umbrella review of the health effects of nutrient and bioactive components found in edible oils and fats

Dietary guidelines for many Western countries base their edible oil and fat recommendations solely on saturated fatty acid content. This study aims to demonstrate which nutritional and bioactive components make up commonly consumed edible oils and fats; and explore the health effects and strength of evidence for key nutritional and bioactive components of edible oils. An umbrella review was conducted in several stages. Food composition databases of Australia and the United States of America, and studies were examined to profile nutrient and bioactive content of edible oils and fats. PUBMED and Cochrane databases were searched for umbrella reviews, systematic literature reviews of randomized controlled trials or cohort studies, individual randomized controlled trials, and individual cohort studies to examine the effect of the nutrient or bioactive on high-burden chronic diseases (cardiovascular disease, type 2 diabetes mellitus, obesity, cancer, mental illness, cognitive impairment). Substantial systematic literature review evidence was identified for fatty acid categories, tocopherols, biophenols, and phytosterols. Insufficient evidence was identified for squalene. The evidence supports high mono- and polyunsaturated fatty acid compositions, total biophenol content, phytosterols, and possibly high α-tocopherol content as having beneficial effects on high-burden health comes. Future dietary guidelines should use a more sophisticated approach to judge edible oils beyond saturated fatty acid content.

Dual derivatization strategy for the comprehensive quantification and double bond location characterization of fatty acids by ultra-high performance liquid chromatography-tandem mass spectrometry

Comprehensive analysis of fatty acids (FAs) has long been challenging due to their poor ionization efficiency, lack of characteristic fragment ions and difficulty of identifying C=C bond locations. In this study, a high coverage ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for the quantification and C=C bond location characterization of FAs using two structural analogues, 2-hydrazinyl-4,6-dimethylpyrimidine (DMP) and 2-hydrazinylpyrimidine (DP), as dual derivatization reagents. DP-labeled FA standards were used as internal standards to reduced matrix effects, which guaranteed the accurate quantification of FAs. The derivatization yields of FAs were larger than 99% and the sensitivities were increased by 400-fold compared with non-derivatized FAs. Pretreatment and instrumental analysis of FAs can be completed in 20 minutes. Only 5 μL rat plasma can satisfy the quantification of 36 FAs with good linearity (r>0.99). Both intra-day and inter-day accuracies were in the range of 85-105%, and the precisions were less than 15%. The extraction recoveries were investigated to be in the range of 88-112%. No obvious matrix effects were observed for the derivatized FAs. In addition, the locations of C=C bonds in DMP-derivatized FAs could be identified by diagnostic fragment ions generated from 1,4-hydrogen elimination and allylic cleavage under low energy collision induced dissociation (CID). The new method was finally employed for FA profiling in plasma from rats with moxifloxacin-induced liver injury. Significant downregulation of butyric acid was observed in moxifloxacin treated model rats, which was believed to be related to the liver injury.

Herring Milt and Herring Milt Protein Hydrolysate Are Equally Effective in Improving Insulin Sensitivity and Pancreatic Beta-Cell Function in Diet-Induced Obese- and Insulin-Resistant Mice

Although genetic predisposition influences the onset and progression of insulin resistance and diabetes, dietary nutrients are critical. In general, protein is beneficial relative to carbohydrate and fat but dependent on protein source. Our recent study demonstrated that 70% replacement of dietary casein protein with the equivalent quantity of protein derived from herring milt protein hydrolysate (HMPH; herring milt with proteins being enzymatically hydrolyzed) significantly improved insulin resistance and glucose homeostasis in high-fat diet-induced obese mice. As production of protein hydrolysate increases the cost of the product, it is important to determine whether a simply dried and ground herring milt product possesses similar benefits. Therefore, the current study was conducted to investigate the effect of herring milt dry powder (HMDP) on glucose control and the associated metabolic phenotypes and further to compare its efficacy with HMPH. Male C57BL/6J mice on a high-fat diet for 7 weeks were randomized based on body weight and blood glucose into three groups. One group continued on the high-fat diet and was used as the insulin-resistant/diabetic control and the other two groups were given the high-fat diet modified to have 70% of casein protein being replaced with the same amount of protein from HMDP or HMPH. A group of mice on a low-fat diet all the time was used as the normal control. The results demonstrated that mice on the high-fat diet increased weight gain and showed higher blood concentrations of glucose, insulin, and leptin, as well as impaired glucose tolerance and pancreatic β-cell function relative to those on the normal control diet. In comparison with the high-fat diet, the replacement of 70% dietary casein protein with the same amount of HMDP or HMPH protein decreased weight gain and significantly improved the aforementioned biomarkers, insulin sensitivity or resistance, and β-cell function. The HMDP and HMPH showed similar effects on every parameter except blood lipids where HMDP decreased total cholesterol and non-HDL-cholesterol levels while the effect of HMPH was not significant. The results demonstrate that substituting 70% of dietary casein protein with the equivalent amount of HMDP or HMPH protein protects against obesity and diabetes, and HMDP is also beneficial to cholesterol homeostasis.

Deregulation of Lipid Homeostasis: A Fa(c)t in the Development of Metabolic Diseases

Lipids are important molecules for human health. The quantity and quality of fats consumed in the diet have important effects on the modulation of both the natural biosynthesis and degradation of lipids. There is an important number of lipid-failed associated metabolic diseases and an increasing number of studies suggesting that certain types of lipids might be beneficial to the treatment of many metabolic diseases. The aim of the present work is to expose an overview of de novo biosynthesis, storage, and degradation of lipids in mammalian cells, as well as, to review the published data describing the beneficial effects of these processes and the potential of some dietary lipids to improve metabolic diseases.

Beneficial effect on serum cholesterol levels, but not glycaemic regulation, after replacing SFA with PUFA for 3 d: a randomised crossover trial

Replacing intake of SFA with PUFA reduces serum cholesterol levels and CVD risk. The effect on glycaemic regulation is, however, less clear. The main objective of the present study was to investigate the short-term effect of replacing dietary SFA with PUFA on glycaemic regulation. Seventeen healthy, normal-weight participants completed a 25-d double-blind, randomised and controlled two-period crossover study. Participants were allocated to either interventions with PUFA products or SFA products (control) in a random order for three consecutive days, separated by a 1·5-week washout period between the intervention periods. Glucose, insulin and TAG were measured before and after an oral glucose tolerance test. In addition, fasting total cholesterol, NEFA and plasma total fatty acid profile were measured before and after the 3-d interventions. Fasting and postprandial glucose, insulin, and TAG levels and fasting levels of NEFA and plasma fatty acid profile did not differ between the groups. However, replacing dietary SFA with PUFA significantly reduced total cholesterol levels by 8 % after 3 d (P = 0·002). Replacing dietary SFA with PUFA for only 3 d has beneficial cardio-metabolic effects by reducing cholesterol levels in healthy individuals.

The Anti-Inflammatory and Antioxidant Properties of n-3 PUFAs: Their Role in Cardiovascular Protection

Polyunsaturated fatty acids (n-3 PUFAs) are long-chain polyunsaturated fatty acids with 18, 20 or 22 carbon atoms, which have been found able to counteract cardiovascular diseases. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in particular, have been found to produce both vaso- and cardio-protective response via modulation of membrane phospholipids thereby improving cardiac mitochondrial functions and energy production. However, antioxidant properties of n-3 PUFAs, along with their anti-inflammatory effect in both blood vessels and cardiac cells, seem to exert beneficial effects in cardiovascular impairment. In fact, dietary supplementation with n-3 PUFAs has been demonstrated to reduce oxidative stress-related mitochondrial dysfunction and endothelial cell apoptosis, an effect occurring via an increased activity of endogenous antioxidant enzymes. On the other hand, n-3 PUFAs have been shown to counteract the release of pro-inflammatory cytokines in both vascular tissues and in the myocardium, thereby restoring vascular reactivity and myocardial performance. Here we summarize the molecular mechanisms underlying the anti-oxidant and anti-inflammatory effect of n-3 PUFAs in vascular and cardiac tissues and their implication in the prevention and treatment of cardiovascular disease.

Adherence to the Mediterranean dietary pattern in relation to glioma: A case-control study

BACKGROUND

Although Mediterranean diet (MD) was associated with a lower risk of mortality and cancer, no data are available investigating the association between adherence to the MD and risk of glioma.

METHODS

In this case-control study, we enrolled a total of 128 newly diagnosed patients with glioma, confirmed by pathological assessment, and 256 hospital-based controls from 2009 to 2011 in Tehran, Iran. A valid and reliable Block-format food frequency questionnaire (FFQ) was used to assess dietary intakes. Adherence to the MD was examined using the scoring method suggested by Trichopoulou et al. Logistic regression was used to examine the associations of interest.

RESULTS

After controlling for age, sex, and energy intake, participants in the highest tertile of MD score had not significantly lower odds of glioma than those in the lowest tertile (OR: 0.58, 95% CI: 0.32-1.03, P_trend = 0.06). However, after taking other potential confounders into account, individuals with the greatest adherence to the MD score were 74% less likely to have glioma than those with the lowest adherence (OR: 0.26, 95% CI: 0.12-0.55, P_trend < 0.001). Additional adjustments for dietary intakes and BMI did not significantly alter this association (OR: 0.36, 95% CI: 0.16-0.78, P_trend = 0.009; OR: 0.36, 95% CI: 0.16-0.78, P_trend = 0.01, respectively).

CONCLUSION

We found that adherence to the MD was associated with a lower likelihood of having glioma. Prospective cohort studies are needed to further examine these findings.

Shaping of Dendritic Cell Function by the Metabolic Micro-Environment

Nutrients are required for growth and survival of all cells, but are also crucially involved in cell fate determination of many cell types, including immune cells. There is a growing appreciation that the metabolic micro-environment also plays a major role in shaping the functional properties of dendritic cells (DCs). Under pathological conditions nutrient availability can range from a very restricted supply, such as seen in a tumor micro-environment, to an overabundance of nutrients found in for example obese adipose tissue. In this review we will discuss what is currently known about the metabolic requirements for DC differentiation and immunogenicity and compare that to how function and fate of DCs under pathological conditions can be affected by alterations in environmental levels of carbohydrates, lipids and amino acids as well as by other metabolic cues, including availability of oxygen, redox homeostasis and lactate levels. Many of these insights have been generated using in vitro model systems, which have revealed highly diverse effects of different metabolic cues on DC function. However, they also stress the importance of shifting toward more physiologically relevant experimental settings to be able to fully delineate the role of the metabolic surroundings in its full complexity in shaping the functional properties of DCs in health and disease.

Prevention of Potential Adverse Metabolic Effects of a Supplementation with Omega-3 Fatty Acids Using a Genetic Score Approach

INTRODUCTION

The consumption of long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) has been reported to have beneficial health effects, notably, by reducing plasma triglyceride levels. Nonetheless, a concomitant decrease in insulin sensitivity has also been observed, but is highly variable among subjects. Herein, we aimed to determine the importance of the genetic background in the interindividual variability of the insulin sensitivity response following an n-3 PUFA supplementation.

METHODS

A total of 210 participants completed a 6-week n-3 PUFA supplementation with 5 g/day of fish oil (providing 1.9-2.2 g of eicosapentaenoic acid + 1.1 g of docosahexaenoic acid). Insulin resistance was estimated by the homeostatic model assessment (HOMA-IR), and participants were further classified as high-risk or low-risk depending on their HOMA-IR change following the n-3 PUFA supplementation, as compared to pre-supplementation values. Genome-wide genotyping data were obtained for 138 participants using HumanOmni-5-Quad BeadChips containing 4,301,331 single nucleotide polymorphisms. A genome-wide association analysis (GWAS) was carried out between high-risk and low-risk participants. The population study was split into training (60%) and testing (40%) datasets to assess the predictive accuracy of a genetic risk score (GRS) constructed by summing the number of risk alleles.

RESULTS

Following the n-3 PUFA supplementation, 32 participants had increased HOMA-IR as compared to initial values and were classified as high risk (23.2%), whereas remaining subjects were classified as low risk (n = 106, 76.8%). A total of 8 loci had frequency differences between high-risk and low-risk participants at a suggestive GWAS association threshold (p value <1 × 10-5). After applying 10-fold cross validation, the GRS showed a significant association with the risk of increased HOMA-IR in the testing dataset (OR = 3.16 [95% CI, 1.85-7.14]), with a predictive accuracy of 0.85, and explained 40% of variation in HOMA-IR change.

CONCLUSIONS

These results suggest that the genetic background has a relevant role in the interindividual variability observed in the insulin sensitivity response following an n-3 PUFA supplementation. Subjects being at risk of insulin sensitivity lowering following an n-3 PUFA supplementation may be identified using genetic-based precision nutrition approaches.

Dietary Intake and Type 2 Diabetes

This editorial aims to examine the risk factors associated with type 2 diabetes and to discuss the evidence relating to dietary strategies for managing people with this condition. It is clear from the evidence presented that a range of dietary interventions can provide useful approaches for managing people with type 2 diabetes, including the regulation of blood glucose and lipid parameters, and for reducing the risks of acute and chronic diabetic complications.

Changes in Plasma Free Fatty Acids Associated with Type-2 Diabetes

Type 2 diabetes mellitus (T2DM) is associated with increased total plasma free fatty acid (FFA) concentrations and an elevated risk of cardiovascular disease. The exact mechanisms by which the plasma FFA profile of subjects with T2DM changes is unclear, but it is thought that dietary fats and changes to lipid metabolism are likely to contribute. Therefore, establishing the changes in concentrations of specific FFAs in an individual’s plasma is important. Each type of FFA has different effects on physiological processes, including the regulation of lipolysis and lipogenesis in adipose tissue, inflammation, endocrine signalling and the composition and properties of cellular membranes. Alterations in such processes due to altered plasma FFA concentrations/profiles can potentially result in the development of insulin resistance and coagulatory defects. Finally, fibrates and statins, lipid-regulating drugs prescribed to subjects with T2DM, are also thought to exert part of their beneficial effects by impacting on plasma FFA concentrations. Thus, it is also interesting to consider their effects on the concentration of FFAs in plasma. Collectively, we review how FFAs are altered in T2DM and explore the likely downstream physiological and pathological implications of such changes.