Serum fatty acids and risk of advanced beta-cell autoimmunity: a nested case-control study among children with HLA-conferred susceptibility to type I diabetes

Dietary Components in the Pathogenesis and Prevention of Type 1 Diabetes in Children

BACKGROUND

Type 1 diabetes (T1D) is a disease closely linked to nutrition and modifications in various dietary components have been part of the effort to prevent or slow the progression of the disease even before the discovery of insulin.

SUMMARY

The scientific focus in the prevention or progression modification of T1D is mostly centered on four dietary compounds and their modifications - gluten and its omission, vitamin D supplementation, omega-3 fatty acids supplementation, and decreasing of the amount of ingested carbohydrates. The aim of this narrative review was to provide an overview of nutritional interventions studied in children either as preventive methods or as modifiers in the early stages of T1D from autoantibody positive individuals to persons with newly diagnosed T1D.

KEY MESSAGES

Our review shows that dietary modifications in various dietary components might be useful but none of them seems to provide universal effects in T1D prevention or progression modification. More research is therefore needed with focus on promising modes of action of individual dietary components.

Fatty acid-mediated signaling as a target for developing type 1 diabetes therapies

INTRODUCTION

Type 1 diabetes (T1D) is an autoimmune disease in which pro-inflammatory and cytotoxic signaling drive the death of the insulin-producing β cells. This complex signaling is regulated in part by fatty acids and their bioproducts, making them excellent therapeutic targets.

AREAS COVERED

We provide an overview of the fatty acid actions on β cells by discussing how they can cause lipotoxicity or regulate inflammatory response during insulitis. We also discuss how diet can affect the availability of fatty acids and disease development. Finally, we discuss development avenues that need further exploration.

EXPERT OPINION

Fatty acids, such as hydroxyl fatty acids, ω-3 fatty acids, and their downstream products, are druggable candidates that promote protective signaling. Inhibitors and antagonists of enzymes and receptors of arachidonic acid and free fatty acids, along with their derived metabolites, which cause pro-inflammatory and cytotoxic responses, have the potential to be developed as therapeutic targets also. Further, because diet is the main source of fatty acid intake in humans, balancing protective and pro-inflammatory/cytotoxic fatty acid levels through dietary therapy may have beneficial effects, delaying T1D progression. Therefore, therapeutic interventions targeting fatty acid signaling hold potential as avenues to treat T1D.

Cord serum metabolic signatures of future progression to immune-mediated diseases

Previous prospective studies suggest that progression to autoimmune diseases is preceded by metabolic dysregulation, but it is not clear which metabolic changes are disease-specific and which are common across multiple immune-mediated diseases. Here we investigated metabolic profiles in cord serum in a general population cohort (All Babies In Southeast Sweden; ABIS), comprising infants who progressed to one or more immune-mediated diseases later in life: type 1 diabetes (n = 12), celiac disease (n = 28), juvenile idiopathic arthritis (n = 9), inflammatory bowel disease (n = 7), and hypothyroidism (n = 6); and matched controls (n = 270). We observed elevated levels of multiple triacylglycerols (TGs) an alteration in several gut microbiota related metabolites in the autoimmune groups. The most distinct differences were observed in those infants who later developed HT. The specific similarities observed in metabolic profiles across autoimmune diseases suggest that they share specific common metabolic phenotypes at birth that contrast with those of healthy controls.

An Oxylipin-Related Nutrient Pattern and Risk of Type 1 Diabetes in the Diabetes Autoimmunity Study in the Young (DAISY)

Oxylipins, pro-inflammatory and pro-resolving lipid mediators, are associated with the risk of type 1 diabetes (T1D) and may be influenced by diet. This study aimed to develop a nutrient pattern related to oxylipin profiles and test their associations with the risk of T1D among youth. The nutrient patterns were developed with a reduced rank regression in a nested case-control study (n = 335) within the Diabetes Autoimmunity Study in the Young (DAISY), a longitudinal cohort of children at risk of T1D. The oxylipin profiles (adjusted for genetic predictors) were the response variables. The nutrient patterns were tested in the case-control study (n = 69 T1D cases, 69 controls), then validated in the DAISY cohort using a joint Cox proportional hazards model (n = 1933, including 81 T1D cases). The first nutrient pattern (NP1) was characterized by low beta cryptoxanthin, flavanone, vitamin C, total sugars and iron, and high lycopene, anthocyanidins, linoleic acid and sodium. After adjusting for T1D family history, the HLA genotype, sex and race/ethnicity, NP1 was associated with a lower risk of T1D in the nested case-control study (OR: 0.44, p = 0.0126). NP1 was not associated with the risk of T1D (HR: 0.54, p-value = 0.1829) in the full DAISY cohort. Future studies are needed to confirm the nested case-control findings and investigate the modifiable factors for oxylipins.

Dietary fatty acid intake in childhood and the risk of islet autoimmunity and type 1 diabetes: the DIPP birth cohort study

PURPOSE

The aim was to study the associations between dietary intake of fatty acids in childhood and the risk of islet autoimmunity and type 1 diabetes (T1D).

METHODS

The prospective Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study included children with genetic susceptibility to T1D born between 1996 and 2004. Participants were followed up every 3 to 12 months up to 6 years for diet, islet autoantibodies, and T1D. Dietary intake of several fatty acids at the age of 3 months to 6 years was assessed 1-8 times per participant with a 3-day food record. Joint models adjusted for energy intake, sex, HLA genotype and familial diabetes were used to investigate the associations of longitudinal intake of fatty acids and the development of islet autoimmunity and T1D.

RESULTS

During the 6-year follow-up, 247 (4.4%) children of 5626 developed islet autoimmunity and 94 (1.7%) children of 5674 developed T1D. Higher intake of monounsaturated fatty acids (HR 0.63; 95% CI 0.47, 0.82), arachidonic acid (0.69; 0.50, 0.94), total n-3 fatty acids (0.64; 0.48, 0.84), and long-chain n-3 fatty acids (0.14; 0.04, 0.43), was associated with a decreased risk of islet autoimmunity with and without energy adjustment. Higher intake of total fat (0.73; 0.53, 0.98), and saturated fatty acids (0.55; 0.33, 0.90) was associated with a decreased risk of T1D only when energy adjusted.

CONCLUSION

Intake of several fatty acids was associated with a decreased risk of islet autoimmunity or T1D among high-risk children. Our findings support the idea that dietary factors, including n-3 fatty acids, may play a role in the disease process of T1D.

Associations Between Serum Fatty Acids and Immunological Markers in Children Developing Islet Autoimmunity-The TRIGR Nested Case-Control Study

Aims

Altered immune functions as well as fatty acid intake and status have been associated with the development of type 1 diabetes. We aimed to study the relationship between fatty acids and immunological markers in young children with increased genetic risk for type 1 diabetes in order to define putative mechanisms related to development of islet autoimmunity.

Methods

Serum samples for fatty acid and immunological marker measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children born between 2002 and 2007 in 15 countries. Case children (n = 95) were defined as having repeated positivity for at least two out of four diabetes-associated autoantibodies. For each case child, control children were selected matched for country and date of birth (n = 173). Serum fatty acids and immunological markers were measured from cord serum and at the age of 6 and 12 months. Spearman correlation coefficients were calculated between fatty acids and immunological markers.

Results

Correlations between circulating fatty acids and immunological markers were different in case children who developed islet autoimmunity than in control children already at birth continuing across the first year of life. In case children, saturated fatty acids (SFAs) showed stronger correlations with immunological markers, while in controls, polyunsaturated fatty acids (PUFAs) showed stronger correlations.

Conclusions

In cases, SFAs were associated with several immunological markers (CXCL10, IL-6, IL-9, IL-17, and CM-CSF) previously linked to the type 1 diabetes disease process. Findings indicate that fatty acids could have immunomodulatory potential in the early phase of the disease development, although causality between fatty acids and the immunological pathways remains to be explored.

Trial registry number

NCT00179777.

Lifestyle or Environmental Influences and Their Interaction With Genetic Susceptibility on the Risk of LADA

BACKGROUND

LADA is a common form of diabetes described as a mix between type 1 and type 2 diabetes. Understanding of how genes and environmental factors interact in the development of LADA is central for future efforts to prevent the disease. This review aims to synthesize the literature on lifestyle factors linked to LADA risk and discuss their potential interaction with genetic susceptibility.

FINDINGS

Current knowledge on environmental risk factors for LADA is primarily based on observational data from Scandinavian populations. Increasing evidence suggest that lifestyle factors promoting type 2 diabetes such as obesity, sedentariness, low birth weight and smoking, is implicated in the risk of LADA. Data from mendelian randomization studies support that the link between LADA and obesity, low birth weight and smoking is causal. Limited evidence indicates that dietary factors including consumption of red meat, coffee and sweetened beverages may increase the risk while consumption of alcohol and omega-3 fatty acids may reduce the risk. Several lifestyle factors, including smoking and obesity, seem to interact with human leukocyte antigen genes associated with autoimmunity, conferring much stronger effects on disease risk among those exposed to both factors.

SUMMARY

Available studies suggest that lifestyle modification has the potential for prevention of LADA, particularly for individuals with high risk of disease such as those with genetic susceptibility. Research into risk factors of LADA is however limited, confirmations are warranted, many factors remain to be explored, and there is a need for intervention studies to assess causality.

Metabolic and Metabolomic Insights Regarding the Omega-3 PUFAs Intake in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is currently considered an autoimmune disease characterized by the destruction of pancreatic β-cells, insulin deficiency, and dysglycemia. Dietary factors, including omega-3 polyunsaturated fatty acids (ω-3 PUFAs), were reported to influence T1DM. Therefore, a better understanding of the potential role of ω-3 PUFAs in the development and progression of T1DM will help to improve the clinical management of the disease. In this review, we explored the current understanding of molecular mechanisms and signaling pathways induced by ω-3 PUFAs and the beneficial effects of ω-3 PUFAs intake in the prevention and treatment of T1DM, as well as the underlying possible metabolomic (lipidomics) changes.

The oxylipin profile is associated with development of type 1 diabetes: the Diabetes Autoimmunity Study in the Young (DAISY)

AIMS/HYPOTHESIS

Oxylipins are lipid mediators derived from polyunsaturated fatty acids. Some oxylipins are proinflammatory (e.g. those derived from arachidonic acid [ARA]), others are pro-resolving of inflammation (e.g. those derived from α-linolenic acid [ALA], docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) and others may be both (e.g. those derived from linoleic acid [LA]). The goal of this study was to examine whether oxylipins are associated with incident type 1 diabetes.

METHODS

We conducted a nested case-control analysis in the Diabetes Autoimmunity Study in the Young (DAISY), a prospective cohort study of children at risk of type 1 diabetes. Plasma levels of 14 ARA-derived oxylipins, ten LA-derived oxylipins, six ALA-derived oxylipins, four DHA-derived oxylipins and two EPA-related oxylipins were measured by ultra-HPLC-MS/MS at multiple timepoints related to autoantibody seroconversion in 72 type 1 diabetes cases and 71 control participants, which were frequency matched on age at autoantibody seroconversion (of the case), ethnicity and sample availability. Linear mixed models were used to obtain an age-adjusted mean of each oxylipin prior to type 1 diabetes. Age-adjusted mean oxylipins were tested for association with type 1 diabetes using logistic regression, adjusting for the high risk HLA genotype HLA-DR3/4,DQB1*0302. We also performed principal component analysis of the oxylipins and tested principal components (PCs) for association with type 1 diabetes. Finally, to investigate potential critical timepoints, we examined the association of oxylipins measured before and after autoantibody seroconversion (of the cases) using PCs of the oxylipins at those visits.

RESULTS

The ARA-related oxylipin 5-HETE was associated with increased type 1 diabetes risk. Five LA-related oxylipins, two ALA-related oxylipins and one DHA-related oxylipin were associated with decreased type 1 diabetes risk. A profile of elevated LA- and ALA-related oxylipins (PC1) was associated with decreased type 1 diabetes risk (OR 0.61; 95% CI 0.40, 0.94). A profile of elevated ARA-related oxylipins (PC2) was associated with increased diabetes risk (OR 1.53; 95% CI 1.03, 2.29). A critical timepoint analysis showed type 1 diabetes was associated with a high ARA-related oxylipin profile at post-autoantibody-seroconversion but not pre-seroconversion.

CONCLUSIONS/INTERPRETATION

The protective association of higher LA- and ALA-related oxylipins demonstrates the importance of both inflammation promotion and resolution in type 1 diabetes. Proinflammatory ARA-related oxylipins may play an important role once the autoimmune process has begun.

Phospholipid Levels at Seroconversion Are Associated With Resolution of Persistent Islet Autoimmunity: The Diabetes Autoimmunity Study in the Young

Reversion of islet autoimmunity (IA) may point to mechanisms that prevent IA progression. We followed 199 individuals who developed IA during the Diabetes Autoimmunity Study in the Young. Untargeted metabolomics was performed in serum samples following IA. Cox proportional hazards models were used to test whether the metabolites (2,487) predicted IA reversion: two or more consecutive visits negative for all autoantibodies. We conducted a principal components analysis (PCA) of the top metabolites; |hazard ratio (HR) >1.25| and nominal P < 0.01. Phosphatidylcholine (16:0_18:1(9Z)) was the strongest individual metabolite (HR per 1 SD 2.16, false discovery rate (FDR)-adjusted P = 0.0037). Enrichment analysis identified four clusters (FDR P < 0.10) characterized by an overabundance of sphingomyelin (d40:0), phosphatidylcholine (16:0_18:1(9Z)), phosphatidylcholine (30:0), and l-decanoylcarnitine. Overall, 63 metabolites met the criteria for inclusion in the PCA. PC1 (HR 1.4, P < 0.0001), PC2 (HR 0.85, P = 0.0185), and PC4 (HR 1.28, P = 0.0103) were associated with IA reversion. Given the potential influence of diet on the metabolome, we investigated whether nutrients were correlated with PCs. We identified 20 nutrients that were correlated with the PCs (P < 0.05). Total sugar intake was the top nutrient. Overall, we identified an association between phosphatidylcholine, sphingomyelin, and carnitine levels and reversion of IA.

Serum fatty acids and risk of developing islet autoimmunity: A nested case-control study within the TRIGR birth cohort

BACKGROUND

Circulating fatty acids have been linked to development of type 1 diabetes.

OBJECTIVES

To study the prospective associations of serum fatty acids with the risk of islet autoimmunity in high-risk children.

METHODS

A nested case-control selection was carried out within the TRIGR cohort, which included infants with HLA (DQB1 or DQA1)-conferred disease susceptibility and a first-degree relative with type 1 diabetes, born between 2002 and 2007 in 15 countries and followed-up until 2017. The present study included 244 case children positive for at least two islet autoantibodies (ICA, IAA, GADA, and IA-2A) and two control children were matched for country and age. Proportions of 26 serum fatty acids at cord blood and at 6, 12, and 18 months of age were assessed using gas-chromatography.

RESULTS

The average proportions of the following fatty acids were associated with an increased risk of islet autoimmunity, adjusted for sex, HLA risk, and maternal type 1 diabetes: pentadecanoic acid (15:0) (OR 3.41: 95% CI 1.70, 6.85), heptadecanoic acid (iso 17:0) (2.64: 1.62, 4.28) and (anteiso 17:0) (2.27: 1.39, 3.70), stearic acid (18:0) (23.8: 2.32, 244.6), and conjugated linoleic acid (18:2n-7) (2.60: 1.47, 4.59). Breastfeeding and not having maternal type 1 diabetes were positively associated with levels of the above-mentioned fatty acids. N-3 fatty acids were not consistently associated with islet autoimmunity.

CONCLUSIONS

We found direct associations of pentadecanoic acid, heptadecanoic acid, stearic acid, and conjugated linoleic acid with the risk of islet autoimmunity. Further studies are needed to understand the complex role of fatty acids in the development of type 1 diabetes.

Children's erythrocyte fatty acids are associated with the risk of islet autoimmunity

Our aim was to investigate the associations between erythrocyte fatty acids and the risk of islet autoimmunity in children. The Environmental Determinants of Diabetes in the Young Study (TEDDY) is a longitudinal cohort study of children at high genetic risk for type 1 diabetes (n = 8676) born between 2004 and 2010 in the U.S., Finland, Sweden, and Germany. A nested case-control design comprised 398 cases with islet autoimmunity and 1178 sero-negative controls matched for clinical site, family history, and gender. Fatty acids composition was measured in erythrocytes collected at the age of 3, 6, and 12 months and then annually up to 6 years of age. Conditional logistic regression models were adjusted for HLA risk genotype, ancestry, and weight z-score. Higher eicosapentaenoic and docosapentaenoic acid (n - 3 polyunsaturated fatty acids) levels during infancy and conjugated linoleic acid after infancy were associated with a lower risk of islet autoimmunity. Furthermore, higher levels of some even-chain saturated (SFA) and monounsaturated fatty acids (MUFA) were associated with increased risk. Fatty acid status in early life may signal the risk for islet autoimmunity, especially n - 3 fatty acids may be protective, while increased levels of some SFAs and MUFAs may precede islet autoimmunity.

Interaction Between GAD65 Antibodies and Dietary Fish Intake or Plasma Phospholipid n-3 Polyunsaturated Fatty Acids on Incident Adult-Onset Diabetes: The EPIC-InterAct Study

OBJECTIVE

Islet autoimmunity is associated with diabetes incidence. We investigated whether there was an interaction between dietary fish intake or plasma phospholipid n-3 polyunsaturated fatty acid (PUFA) concentration with the 65-kDa isoform of GAD (GAD65) antibody positivity on the risk of developing adult-onset diabetes.

RESEARCH DESIGN AND METHODS

We used prospective data on 11,247 incident cases of adult-onset diabetes and 14,288 noncases from the EPIC-InterAct case-cohort study conducted in eight European countries. Baseline plasma samples were analyzed for GAD65 antibodies and phospholipid n-3 PUFAs. Adjusted hazard ratios (HRs) for incident diabetes in relation to GAD65 antibody status and tertiles of plasma phospholipid n-3 PUFA or fish intake were estimated using Prentice-weighted Cox regression. Additive (proportion attributable to interaction [AP]) and multiplicative interactions between GAD65 antibody positivity (≥65 units/mL) and low fish/n-3 PUFA were assessed.

RESULTS

The hazard of diabetes in antibody-positive individuals with low intake of total and fatty fish, respectively, was significantly elevated (HR 2.52 [95% CI 1.76-3.63] and 2.48 [1.79-3.45]) compared with people who were GAD65 antibody negative and had high fish intake, with evidence of additive (AP 0.44 [95% CI 0.16-0.72] and 0.48 [0.24-0.72]) and multiplicative (P = 0.0465 and 0.0103) interactions. Individuals with high GAD65 antibody levels (≥167.5 units/mL) and low total plasma phospholipid n-3 PUFAs had a more than fourfold higher hazard of diabetes (HR 4.26 [2.70-6.72]) and an AP of 0.46 (0.12-0.80) compared with antibody-negative individuals with high n-3 PUFAs.

CONCLUSIONS

High fish intake or relative plasma phospholipid n-3 PUFA concentrations may partially counteract the increased diabetes risk conferred by GAD65 antibody positivity.

The Interplay Between Diet and the Epigenome in the Pathogenesis of Type-1 Diabetes

The autoimmune disease, Type 1 Diabetes Mellitus (T1DM), results in the destruction of pancreatic β-cells, and the International Diabetes Federation reports that its incidence is increasing worldwide. T1DM is a complex disease due to the interaction between genetic and environmental factors. Certain dietary patterns and nutrients are known to cause epigenetic modifications in physiological conditions and diseases. However, the interplay between diet and epigenetics is not yet well-understood in the context of T1DM. Several studies have described epigenetic mechanisms involved in the autoimmune reactions that destroy the β-cells, but few explored diet components as potential triggers for epigenetic modifications. Clarifying the link between diet and epigenome can provide new insights into the pathogenesis of T1DM, potentially leading to new diagnostic and therapeutic approaches. In this mini review, we shed light on the influence of the diet-epigenome axis on the pathophysiology of T1DM.

Plasma Metabolome and Circulating Vitamins Stratified Onset Age of an Initial Islet Autoantibody and Progression to Type 1 Diabetes: The TEDDY Study

Children's plasma metabolome, especially lipidome, reflects gene regulation and dietary exposures, heralding the development of islet autoantibodies (IA) and type 1 diabetes (T1D). The Environmental Determinants of Diabetes in the Young (TEDDY) study enrolled 8,676 newborns by screening of HLA-DR-DQ genotypes at six clinical centers in four countries, profiled metabolome, and measured concentrations of ascorbic acid, 25-hydroxyvitamin D [25(OH)D], and erythrocyte membrane fatty acids following birth until IA seroconversion under a nested case-control design. We grouped children having an initial autoantibody only against insulin (IAA-first) or GAD (GADA-first) by unsupervised clustering of temporal lipidome, identifying a subgroup of children having early onset of each initial autoantibody, i.e., IAA-first by 12 months and GADA-first by 21 months, consistent with population-wide early seroconversion age. Differential analysis showed that infants having reduced plasma ascorbic acid and cholesterol experienced IAA-first earlier, while early onset of GADA-first was preceded by reduced sphingomyelins at infancy. Plasma 25(OH)D prior to either autoantibody was lower in T1D progressors compared with nonprogressors, with simultaneous lower diglycerides, lysophosphatidylcholines, triglycerides, and alanine before GADA-first. Plasma ascorbic acid and 25(OH)D at infancy were lower in HLA-DR3/DR4 children among IA case subjects but not in matched control subjects, implying gene expression dysregulation of circulating vitamins as latent signals for IA or T1D progression.

Consumption of red meat, genetic susceptibility, and risk of LADA and type 2 diabetes

Purpose

Red meat consumption is positively associated with type 1 (T1D) and type 2 (T2D) diabetes. We investigated if red meat consumption increases the risk of latent autoimmune diabetes in adults (LADA) and T2D, and potential interaction with family history of diabetes (FHD), HLA and TCF7L2 genotypes.

Methods

Analyses were based on Swedish case–control data comprising incident cases of LADA (n = 465) and T2D (n = 1528) with matched, population-based controls (n = 1789; n = 1553 in genetic analyses). Multivariable-adjusted ORs in relation to self-reported processed and unprocessed red meat intake were estimated by conditional logistic regression models. Attributable proportion (AP) due to interaction was used to assess departure from additivity of effects.

Results

Consumption of processed red meat was associated with increased risk of LADA (per one servings/day OR 1.27, 95% CI 1.07–1.52), whereas no association was observed for unprocessed red meat. For T2D, there was no association with red meat intake once BMI was taken into account. The combination of high (> 0.3 servings/day vs. less) processed red meat intake and high-risk HLA-DQB1 and -DRB1 genotypes yielded OR 8.05 (95% CI 4.86–13.34) for LADA, with indications of significant interaction (AP 0.53, 95% CI 0.32–0.73). Results were similar for the combination of FHD-T1D and processed red meat. No interaction between processed red meat intake and FHD-T2D or risk variants of TCF7L2 was seen in relation to LADA or T2D.

Conclusion

Consumption of processed but not unprocessed red meat may increase the risk of LADA, especially in individuals with FHD-T1D or high-risk HLA genotypes.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02285-2) contains supplementary material, which is available to authorized users.

Current understandings of the pathogenesis of type 1 diabetes: Genetics to environment

Type 1 diabetes (T1D) is an autoimmune disease that usually strikes early in life, but can affect individuals at almost any age. It is caused by autoreactive T cells that destroy insulin-producing beta cells in the pancreas. Epidemiological studies estimate a prevalence of 1 in 300 children in the United States with an increasing incidence of 2%-5% annually worldwide. The daily responsibility, clinical management, and vigilance required to maintain blood sugar levels within normal range and avoid acute complications (hypoglycemic episodes and diabetic ketoacidosis) and long term micro- and macro-vascular complications significantly affects quality of life and public health care costs. Given the expansive impact of T1D, research work has accelerated and T1D has been intensively investigated with the focus to better understand, manage and cure this condition. Many advances have been made in the past decades in this regard, but key questions remain as to why certain people develop T1D, but not others, with the glaring example of discordant disease incidence among monozygotic twins. In this review, we discuss the field’s current understanding of its pathophysiology and the role of genetics and environment on the development of T1D. We examine the potential implications of these findings with an emphasis on T1D inheritance patterns, twin studies, and disease prevention. Through a better understanding of this process, interventions can be developed to prevent or halt it at early stages.

Metabolite-related dietary patterns and the development of islet autoimmunity

The role of diet in type 1 diabetes development is poorly understood. Metabolites, which reflect dietary response, may help elucidate this role. We explored metabolomics and lipidomics differences between 352 cases of islet autoimmunity (IA) and controls in the TEDDY (The Environmental Determinants of Diabetes in the Young) study. We created dietary patterns reflecting pre-IA metabolite differences between groups and examined their association with IA. Secondary outcomes included IA cases positive for multiple autoantibodies (mAb+). The association of 853 plasma metabolites with outcomes was tested at seroconversion to IA, just prior to seroconversion, and during infancy. Key compounds in enriched metabolite sets were used to create dietary patterns reflecting metabolite composition, which were then tested for association with outcomes in the nested case-control subset and the full TEDDY cohort. Unsaturated phosphatidylcholines, sphingomyelins, phosphatidylethanolamines, glucosylceramides, and phospholipid ethers in infancy were inversely associated with mAb+ risk, while dicarboxylic acids were associated with an increased risk. An infancy dietary pattern representing higher levels of unsaturated phosphatidylcholines and phospholipid ethers, and lower sphingomyelins was protective for mAb+ in the nested case-control study only. Characterization of this high-risk infant metabolomics profile may help shape the future of early diagnosis or prevention efforts.

Understanding of type 1 diabetes mellitus: what we know and where we go

The incidence of type 1 diabetes mellitus (T1DM) in children and adolescents is increasing worldwide. Combined effects of genetic and environmental factors cause T1DM, which make it difficult to predict whether an individual will inherit the disease. Due to the level of self-care necessary in T1DM maintenance, it is crucial for pediatric settings to support achieving optimal glucose control, especially when adolescents are beginning to take more responsibility for their own health. Innovative insulin delivery systems, such as continuous subcutaneous insulin infusion (CSII), and noninvasive glucose monitoring systems, such as continuous glucose monitoring (CGM), allow patients with T1DM to achieve a normal and flexible lifestyle. However, there are still challenges in achieving optimal glucose control despite advanced technology in T1DM administration. In this article, disease prediction and current management of T1DM are reviewed with special emphasis on biomarkers of pancreatic β-cell stress, CSII, glucose monitoring, and several other adjunctive therapies.

Intake of polyunsaturated fatty acids and risk of preclinical and clinical type 1 diabetes in children-a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

The association between the intake of polyunsaturated fatty acids (PUFAs) and the risk of preclinical and clinical type 1 diabetes (T1D) in children has generated conflicting results. Thus, we aimed to evaluate the definite effects of PUFAs on the risk of preclinical and clinical T1D.

SUBJECTS/METHODS

Three databases were systematically searched up to July 18, 2017 to identify relevant observational studies, without language restriction. Any study included should report the risk of preclinical or clinical T1D in children with PUFAs supplementation compared with the controls, and report relative risks (RRs) or odds ratios (ORs) or provide data for estimation. Pooled RRs (or ORs) with 95% confidence intervals (CI) were calculated using random-effects models irrespective of statistical heterogeneity assessed by I² statistic.

RESULTS

We identified seven studies (three prospective cohort studies and four case-control studies) on PUFAs intake during pregnancy or during early life in children. The pooled RR between the risk of preclinical T1D and n-3 PUFAs supplementation against controls was 0.98 (95%CI, 0.85-1.13), with no heterogeneity. The results were similar after the intake during pregnancy, but not during early life in children (pooled RR, 0.45; 95%CI, 0.21-0.96; P = 0.039). N-3 PUFAs supplementation was not associated with a significant reduction in the risk of clinical T1D in children (pooled RR, 0.87; 95%CI, 0.71-1.08), with substantial heterogeneity(I² = 64.7%). No association was also found between n-6 PUFAs intake and the risk of preclinical (1.07; 0.97-1.017) or clinical T1D (1.05; 0.92-1.20) in children.

CONCLUSIONS

The result of the meta-analysis does not support that n-3 or n-6 PUFAs supplementation in children affects the overall risk of preclinical or clinical T1D. However, n-3 PUFAs intake in early life might reduce the risk of preclinical T1D. Therefore, this finding should be verified by more and well-designed prospective research in the future.

Fatty acid status in infancy is associated with the risk of type 1 diabetes-associated autoimmunity

AIMS/HYPOTHESIS

We investigated the association of early serum fatty acid composition with the risk of type 1 diabetes-associated autoimmunity. Our hypothesis was that fatty acid status during infancy is related to type 1 diabetes-associated autoimmunity and that long-chain n-3 fatty acids, in particular, are associated with decreased risk.

METHODS

We performed a nested case-control analysis within the Finnish Type 1 Diabetes Prediction and Prevention Study birth cohort, carrying HLA-conferred susceptibility to type 1 diabetes (n = 7782). Serum total fatty acid composition was analysed by gas chromatography in 240 infants with islet autoimmunity and 480 control infants at the age of 3 and 6 months. Islet autoimmunity was defined as repeated positivity for islet cell autoantibodies in combination with at least one of three selected autoantibodies. In addition, a subset of 43 infants with primary insulin autoimmunity (i.e. those with insulin autoantibodies as the first autoantibody with no concomitant other autoantibodies) and a control group (n = 86) were analysed. A third endpoint was primary GAD autoimmunity defined as GAD autoantibody appearing as the first antibody without other concomitant autoantibodies (22 infants with GAD autoimmunity; 42 infants in control group). Conditional logistic regression was applied, considering multiple comparisons by false discovery rate <0.05.

RESULTS

Serum fatty acid composition differed between breastfed and non-breastfed infants, reflecting differences in the fatty acid composition of the milk. Fatty acids were associated with islet autoimmunity (higher serum pentadecanoic, palmitic, palmitoleic and docosahexaenoic acids decreased risk; higher arachidonic:docosahexaenoic and n-6:n-3 acid ratios increased risk). Furthermore, fatty acids were associated with primary insulin autoimmunity, these associations being stronger (higher palmitoleic acid, cis-vaccenic, arachidonic, docosapentaenoic and docosahexaenoic acids decreased risk; higher α-linoleic acid and arachidonic:docosahexaenoic and n-6:n-3 acid ratios increased risk). Moreover, the quantity of breast milk consumed per day was inversely associated with primary insulin autoimmunity, while the quantity of cow's milk consumed per day was directly associated.

CONCLUSIONS/INTERPRETATION

Fatty acid status may play a role in the development of type 1 diabetes-associated autoimmunity. Fish-derived fatty acids may be protective, particularly during infancy. Furthermore, fatty acids consumed during breastfeeding may provide protection against type 1 diabetes-associated autoimmunity. Further studies are warranted to clarify the independent role of fatty acids in the development of type 1 diabetes.

Dietary factors in the development of type 1 diabetes

There are several indicators concerning the putative importance of dietary factors during the fetal period lactation, infancy and childhood in the etiology of type 1 diabetes. Among foods, cow's milk consumption has been associated with an increased risk of preclinical and/or clinical type 1 diabetes and sugars with a progression from preclinical to clinical disease. Breast milk, on the other hand, may be protective. Processed foods may be related to a greater risk of type 1 diabetes because they contain higher amounts of advanced glycation end-products. Nitrites or N-nitroso compounds in processed meat products could increase the risk of this disease. Among nutrients, n-3 fatty acids, vitamins D and E, and zinc may protect from preclinical and/or clinical type 1 diabetes. The microbial composition of foods or food's other effects on gut microbiota are receiving increasing attention, also due to their putative role in the development of type 1 diabetes. Still the number of prospective studies in this research field is limited and most of the findings remain to be replicated.

Environmental risk factors for type 1 diabetes

The incidence of type 1 diabetes has risen considerably in the past 30 years due to changes in the environment that have been only partially identified. In this Series paper, we critically discuss candidate triggers of islet autoimmunity and factors thought to promote progression from autoimmunity to overt type 1 diabetes. We revisit previously proposed hypotheses to explain the growth in the incidence of type 1 diabetes in light of current data. Finally, we suggest a unified model in which immune tolerance to β cells can be broken by several environmental exposures that induce generation of hybrid peptides acting as neoautoantigens.

Maternal intake of fatty acids and their food sources during lactation and the risk of preclinical and clinical type 1 diabetes in the offspring

AIMS

We examined maternal dietary intake of fatty acids and foods which are sources of fatty acids during lactation and whether they are associated with the risk of preclinical and clinical type 1 diabetes in the offspring.

METHODS

The subjects comprised a cohort of 2,939 mother-child pairs from the prospective Type 1 Diabetes Prediction and Prevention Study. Composition of maternal diet during the third month of lactation was assessed by a validated food frequency questionnaire. Among the children with HLA-conferred susceptibility to type 1 diabetes, 172 developed preclinical and 81 clinical diabetes. Average follow-up for preclinical type 1 diabetes was 7.5 years (range 0.2-14.0 years) and for clinical type 1 diabetes 7.7 years (0.2-14.0 years).

RESULTS

Maternal intake of fatty acids during lactation was not associated with the risk of type 1 diabetes in the offspring. After adjusting for putative confounders, maternal total consumption of red meat and meat products during lactation was associated both with increased risk for preclinical [hazard ratio (HR) 1.19, 95 % CI 1.02-1.40, p = 0.038] and clinical type 1 diabetes (HR 1.27, 95 % CI 1.06-1.52, p = 0.025). In particular, consumption of processed meat products showed an association with increased risk for type 1 diabetes (HR 1.23, 95 % CI 1.02-1.48, p = 0.045). Maternal use of vegetable oils was associated with increased risk for preclinical type 1 diabetes (HR 1.21, 95 % CI 1.03-1.41, p = 0.023).

CONCLUSIONS

Maternal consumption of red meat, especially processed meat, during lactation may increase the risk of type 1 diabetes.

Erythrocyte membrane docosapentaenoic acid levels are associated with islet autoimmunity: the Diabetes Autoimmunity Study in the Young

AIMS/HYPOTHESES

We previously reported that lower n-3 fatty acid intake and levels in erythrocyte membranes were associated with increased risk of islet autoimmunity (IA) but not progression to type 1 diabetes in children at increased risk for diabetes. We hypothesise that specific n-3 fatty acids and genetic markers contribute synergistically to this increased risk of IA in the Diabetes Autoimmunity Study in the Young (DAISY).

METHODS

DAISY is following 2,547 children at increased risk for type 1 diabetes for the development of IA, defined as being positive for glutamic acid decarboxylase (GAD)65, IA-2 or insulin autoantibodies on two consecutive visits. Using a case-cohort design, erythrocyte membrane fatty acids and dietary intake were measured prospectively in 58 IA-positive children and 299 IA-negative children.

RESULTS

Lower membrane levels of the n-3 fatty acid, docosapentaenoic acid (DPA), were predictive of IA (HR 0.23; 95% CI 0.09, 0.55), while α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were not, adjusting for HLA and diabetes family history. We examined whether the effect of dietary intake of the n-3 fatty acid ALA on IA risk was modified by fatty acid elongation and desaturation genes. Adjusting for HLA, diabetes family history, ethnicity, energy intake and questionnaire type, ALA intake was significantly more protective for IA in the presence of an increasing number of minor alleles at FADS1 rs174556 (pinteraction = 0.017), at FADS2 rs174570 (pinteraction = 0.016) and at FADS2 rs174583 (pinteraction = 0.045).

CONCLUSIONS/INTERPRETATION

The putative protective effect of n-3 fatty acids on IA may result from a complex interaction between intake and genetically controlled fatty acid desaturation.

Maternal dietary fatty acid intake during pregnancy and the risk of preclinical and clinical type 1 diabetes in the offspring

The aim of the present study was to examine the associations between the maternal intake of fatty acids during pregnancy and the risk of preclinical and clinical type 1 diabetes in the offspring. The study included 4887 children with human leucocyte antigen (HLA)-conferred type 1 diabetes susceptibility born during the years 1997–2004 from the Finnish Type 1 Diabetes Prediction and Prevention Study. Maternal diet was assessed with a validated FFQ. The offspring were observed at 3- to 12-month intervals for the appearance of type 1 diabetes-associated autoantibodies and development of clinical type 1 diabetes (average follow-up period: 4·6 years (range 0·5–11·5 years)). Altogether, 240 children developed preclinical type 1 diabetes and 112 children developed clinical type 1 diabetes. Piecewise linear log-hazard survival model and Cox proportional-hazards regression were used for statistical analyses. The maternal intake of palmitic acid (hazard ratio (HR) 0·82, 95 % CI 0·67, 0·99) and high consumption of cheese during pregnancy (highest quarter v. intermediate half HR 0·52, 95 % CI 0·31, 0·87) were associated with a decreased risk of clinical type 1 diabetes. The consumption of sour milk products (HR 1·14, 95 % CI 1·02, 1·28), intake of protein from sour milk (HR 1·15, 95 % CI 1·02, 1·29) and intake of fat from fresh milk (HR 1·43, 95 % CI 1·04, 1·96) were associated with an increased risk of preclinical type 1 diabetes, and the intake of low-fat margarines (HR 0·67, 95 % CI 0·49, 0·92) was associated with a decreased risk. No conclusive associations between maternal fatty acid intake or food consumption during pregnancy and the development of type 1 diabetes in the offspring were detected.

High meat consumption is associated with type 1 diabetes mellitus in a Sardinian case-control study

The large worldwide variation in type 1 diabetes incidence and increasing incidence over time points toward important environmental risk factors. Among them, nutrition plays an important role. The objective was to investigate the relationship between type 1 diabetes and nutritional factors in pregnancy and early in life. We carried out, using semi-quantitative food frequency questionnaires, a retrospective case-control study in 298 children of 0-15 years old, 145 of which were affected by type 1 diabetes. The diet of all children and of their mothers during pregnancy and lactation was assessed. In children, a statistically significant dose-response association between type 1 diabetes and the amount of meat consumption was found while no other nutritional factors were associated with the disease. High meat consumption seems to be an important early in life cofactor for type 1 diabetes development, although these findings need to be confirmed in wider prospective follow-up studies.

Red meat, dietary heme iron, and risk of type 2 diabetes: the involvement of advanced lipoxidation endproducts

There is growing evidence of disordered iron homeostasis in the diabetic condition, with links proposed between dietary iron intakes and both the risk of disease and the risk of complications of advanced disease. In the United States, Britain, and Canada, the largest dietary contributors of iron are cereals and cereal products and meat and meat products. This review discusses the findings of cohort studies and meta-analyses of heme iron and red meat intakes and the risk of type 2 diabetes. These suggest that processed red meat is associated with increased risk, with high intakes of red meat possibly also associated with a small increased risk. Historically, humans have relied on large quantities of heme iron and red meat in their diets, and therefore it is paradoxical that iron from meat sources should be associated with the risk of type 2 diabetes. A reason for this association may be drawn from studies of dietary advanced glycation and lipoxidation endproducts present in processed food and the mechanisms by which insulin output by pancreatic islet cells might be influenced by the protein modifications present in processed red meat.

Nutritional factors and preservation of C-peptide in youth with recently diagnosed type 1 diabetes: SEARCH Nutrition Ancillary Study

OBJECTIVE

To test the novel hypothesis that nutritional factors previously associated with type 1 diabetes etiology or with insulin secretion are prospectively associated with fasting C-peptide (FCP) concentration among youth recently diagnosed with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Included were 1,316 youth with autoantibody-positive type 1 diabetes who participated in the SEARCH for Diabetes in Youth study (baseline disease duration, 9.9 months; SD, 6.3). Nutritional exposures included breastfeeding and age at introduction of complementary foods, baseline plasma long-chain omega-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), vitamin D, vitamin E, and, from a baseline food frequency questionnaire, estimated intake of the branched-chain amino acid leucine and total carbohydrate. Multiple linear regression models were conducted to relate each nutritional factor to baseline FCP adjusted for demographics, disease-related factors, and other confounders. Prospective analyses included the subset of participants with preserved β-cell function at baseline (baseline FCP ≥0.23 ng/mL) with additional adjustment for baseline FCP and time (mean follow-up, 24.3 months; SD, 8.2; n = 656). FCP concentration was analyzed as log(FCP).

RESULTS

In adjusted prospective analyses, baseline EPA (P = 0.02), EPA plus DHA (P = 0.03), and leucine (P = 0.03) were each associated positively and significantly with FCP at follow-up. Vitamin D was unexpectedly inversely associated with FCP (P = 0.002).

CONCLUSIONS

Increased intake of branched-chain amino acids and long-chain omega-3 fatty acids may support preservation of β-cell function. This represents a new direction for research to improve prognosis for type 1 diabetes.

Fatty acids modulate cytokine and chemokine secretion of stimulated human whole blood cultures in diabetes

Fatty acids, uric acid and glucose are thought to contribute to subclinical inflammation associated with diabetes mellitus. We tested whether co-incubation of free fatty acids and uric acid or glucose influences the secretion of immune mediators from stimulated human whole blood in vitro. Fresh whole blood samples from 20 healthy subjects, 20 patients with type 1 diabetes and 23 patients with type 2 diabetes were incubated for 24 h with palmitic acid (PAL), linolenic acid (LIN) or eicosapentaenoic acid (EPA) alone or together with elevated concentrations of uric acid or glucose. Concentrations of proinflammatory cytokines interleukin (IL)-1β, IL-2, IL-12(p70), IL-18, IFN-γ, of regulatory cytokines IL-4, IL-10, IL-17 and chemokine CCL2 (MCP-1) were measured by multiplex-bead technology from supernatants. Co-incubation of fatty acids with uric acid resulted in a significant reduction of IL-10, IL-12(p70), IFN-γ and CCL2 (MCP-1) concentrations in supernatants compared to incubation with uric acid alone (P < 0·0001). In contrast, IL-18 was up-regulated upon co-stimulation with fatty acids and uric acid. Similarly, co-incubation of fatty acids with glucose diminished secretion of IL-10, IFN-γ and CCL2 (monocyte chemotactic protein-1), while IL-8 was up-regulated (P < 0·001). Samples from healthy and diabetic subjects did not differ after adjustment for age, sex, body mass index and diabetes type. All three fatty acids similarly influenced whole blood cytokine release in vitro and modulated uric acid or glucose-stimulated cytokine secretion. Although the ω-3-fatty acid EPA showed slightly stronger effects, further studies are required to elaborate the differential effects of PAL, LIN and EPA on disease risk observed previously in epidemiological studies.

Meat consumption, diabetes, and its complications

Several prospective studies have reported that risk of type 2 diabetes (T2DM) is elevated in meat consumers, especially when processed meats are consumed. Elevated risks of coronary heart disease (CHD) and stroke in meat consumers have also been reported. In this overview, the evidence regarding meat consumption and the risk of diabetes, both type 1 diabetes (T1DM) and T2DM and their macro- and microvascular complications, is reviewed. For T2DM, we performed a new meta-analysis including publications up to October 2012. For T1DM, only a few studies have reported increased risks for meat consumers or for high intake of saturated fatty acids and nitrates and nitrites. For T2DM, CHD, and stroke, the evidence is strongest. Per 100 g of total meat, the pooled relative risk (RR) for T2DM is 1.15 (95 % CI 1.07-1.24), for (unprocessed) red meat 1.13 (95 % CI 1.03-1.23), and for poultry 1.04 (95 % CI 0.99-1.33); per 50 g of processed meat, the pooled RR is 1.32 (95 % CI 1.19-1.48). Hence, the strongest association regarding T2DM is observed for processed (red) meat. A similar observation has been made for CHD. For stroke, however, a recent meta-analysis shows moderately elevated risks for meat consumers, for processed as well as for fresh meats. For the microvascular complications of diabetes, few prospective data were available, but suggestions for elevated risks can be derived from findings on hyperglycemia and hypertension. The results are discussed in the light of the typical nutrients and other compounds present in meat--that is, saturated and trans fatty acids, dietary cholesterol, protein and amino acids, heme-iron, sodium, nitrites and nitrosamines, and advanced glycation end products. In light of these findings, a diet moderate to low in red meat, unprocessed and lean, and prepared at moderate temperatures is probably the best choice from the public health point of view.

Serum long chain n-3 fatty acids (EPA and DHA) in the pregnant mother are independent of risk of type 1 diabetes in the offspring

BACKGROUND

This article aims to study whether higher proportions of the long chain n-3 fatty acids eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in the phospholipid fraction of serum samples in pregnancy were associated with a lower risk of childhood onset type 1 diabetes in the offspring.

METHODS

In a prospective cohort of nearly 30 000 pregnant women who gave birth in Norway during 1992-1994, we analysed serum samples from 89 women whose child developed type 1 diabetes and was included in the nationwide Norwegian Childhood Diabetes Registry and 125 randomly selected women whose child did not develop type 1 diabetes before 15 years of age. Specific fatty acids were expressed as the proportion of total fatty acids (g/100 g) in the phospholipid fraction in serum analysed using solid phase extraction and gas chromatography with flame ionization detection.

RESULTS

There was no significant association between EPA or DHA in maternal serum and risk of type 1 diabetes in the offspring. Odds ratio (OR) for upper versus lower quartile of EPA was 0.75 [95% confidence interval (CI) 0.34-1.65], test for trend p = 0.4, and for DHA OR = 0.71 (95% CI 0.33-1.53), test for trend p = 0.6. No significant association was found for the sum of n-3 fatty acids, or for n-6/n-3 ratio in the mother with risk of type 1 diabetes in the offspring.

CONCLUSIONS

Our data did not support the hypothesis that higher proportions of maternal EPA or DHA during pregnancy are associated with a lower risk of type 1 diabetes in the offspring.

Food consumption and advanced β cell autoimmunity in young children with HLA-conferred susceptibility to type 1 diabetes: a nested case-control design

BACKGROUND

Evidence for the role of food consumption during childhood in the development of β cell autoimmunity is scarce and fragmentary.

OBJECTIVE

We set out to study the associations of longitudinal food consumption in children with the development of advanced β cell autoimmunity.

DESIGN

Children with advanced β cell autoimmunity (n = 232) (ie, with repeated positivity for antibodies against islet cells) together with positivity for at least one of the other 3 antibodies analyzed or clinical type 1 diabetes were identified from a prospective birth cohort of 6069 infants with HLA-DQB1-conferred susceptibility to type 1 diabetes who were born in 1996-2004, with the longest follow-up to the age of 11 y. Repeated 3-d food records were completed by the families and daycare personnel. Diabetes-associated autoantibodies and diets were measured at 3-12-mo intervals. Four control subjects, who were matched for birth date, sex, area, and genetic risk, were randomly selected for each case.

RESULTS

In the main food groups, only intakes of cow-milk products (OR: 1.05; 95% CI: 1.00, 1.10) and fruit and berry juices (OR: 1.09; 95% CI: 1.02, 1.12) were significantly, although marginally, associated with advanced β cell autoimmunity. The consumption of fresh milk products and cow milk-based infant formulas was related to the endpoint, whereas no evidence was shown for consumption of sour milk products and cheese. The intake of fat from all milk products and protein from fresh milk products was associated with risk of advanced β cell autoimmunity.

CONCLUSION

Intakes of cow milk and fruit and berry juices could be related to the development of advanced β cell autoimmunity. This trial was registered at clinicaltrials.gov as number NCT00223613.

Fatty acids in serum and diet--a canonical correlation analysis among toddlers

Fatty acid concentrations in blood are potential biomarkers of dietary fat intake, but methodological studies among children are scarce. The large number of fatty acids and their complex interrelationships pose a special challenge in research on fatty acids. Our target was to assess the interrelationships between the total fatty acid profiles in diet and serum of young children. The study subjects were healthy control children from the birth cohort of the Type 1 Diabetes Prediction and Prevention Study. A 3-day food record and a frozen serum sample were available from 135 children at the age of 1 year, from 133 at 2 years, and from 92 at 3 years. The relationship between dietary and serum fatty acid profiles was analysed using canonical correlation analysis. The consumption of fatty milk correlated positively with serum fatty acids, pentadecanoic acid, palmitic acid and conjugated linoleic acid (CLA) at all ages. Correlations between dietary and serum eicosapentaenoic and/or docosahexaenoic acid were observed at 2 and 3 years of age. Serum linoleic acid was positively associated with the consumption of infant formula at the age of 1 year, and with the consumption of vegetable margarine at 2 and 3 years. The results indicate a high quality of the 3-day food records kept by parents and other caretakers of the children, and suitability of non-fasting, un-fractioned serum samples for total fatty acid analyses. The correlation between intake of milk fat and serum proportion of CLA is a novel finding.

Infant and childhood diet and type 1 diabetes risk: recent advances and prospects

Type 1 diabetes is a chronic autoimmune disease characterized by a preclinical period of autoimmunity. It is well accepted that both genetic and environmental factors contribute to disease risk. Given that type 1 diabetes, and its preclinical autoimmunity, appear early in life, infant and childhood diet have been implicated as potential initiating exposures in the etiology of the disease. Several publications in the past year have provided further evidence for existing hypotheses regarding the roles of wheat, cow's milk, omega-3 fatty acids, and the maternal diet during pregnancy. However, inconsistencies in findings between studies suggest the need for collaboration and standardization of study methods to move forward in research in this area. One such example of this is the TEDDY (The Environmental Determinants of Diabetes in the Young) study, which is an international, multicenter birth cohort study with standardized recruitment, dietary collection methodologies, and analytic approaches.