Milk and diabetes

Dairy: Friend or Foe? Bovine Milk-Derived Extracellular Vesicles and Autoimmune Diseases

Due to the availability, scalability, and low immunogenicity, bovine milk-derived extracellular vesicles (MEVs) are increasingly considered to be a promising carrier of nanomedicines for future therapy. However, considering that extracellular vesicles (EVs) are of biological origin, different sources of EVs, including the host origin and the specific cells that produce the EVs, may have different effects on the structure and function of EVs. Additionally, MEVs play an important role in immune regulation, due to their evolutionary conserved cargo, such as cytokines and miRNAs. Their potential effects on different organs, as well as their accumulation in the human body, should not be overlooked. In this review, we have summarized current impacts and research progress brought about by utilizing MEVs as nano-drug carriers. Nevertheless, we also aim to explore the possible connections between the molecules involved in cellular immunity, cytokines and miRNAs of MEVs produced under different health conditions, and autoimmune diseases.

Metabolic effects of milk fatty acids: A literature review

Milk and dairy products are known to have a significant role in human development and tissue maintenance due to their high nutritional value. With the higher incidence of obesity and metabolic diseases, nutrition and public health authorities have recommended the intake of fat-free or low-fat dairy due to the saturated fatty acid content of whole-fat products and their effect on serum cholesterol levels. However, recent studies have questioned the association between milk fat consumption and cardiometabolic risk. This literature review aims to compile the scientific evidence of the metabolic effects of milk fatty acids in clinical and basic research studies, as well as their relationship with metabolic disorders and gut microbiota composition. Research shows that various milk fatty acids exert effects on metabolic alterations (obesity, type 2 diabetes and cardiovascular diseases) by modifying glucose homeostasis, inflammation and lipid profile-related factors. Additionally, recent studies have associated the consumption of milk fatty acids with the production of metabolites and the promotion of healthy gut microbiota. From mainly observational studies, evidence suggests that milk and dairy fatty acids are not directly linked to cardiometabolic risk, but further controlled research is necessary to clarify such findings and to assess whether dietary recommendations to choose low-fat dairy foods are necessary for the population for the prevention of obesity and cardiometabolic disease.

[Variation in the level of the biocomponents immunoglobulin A and lactoferrin in human milk after Holder pasteurization]

BACKGROUND

breast milk is the ideal food for newborns and infants, but there are factors that can prevent the practice of breastfeeding. Human milk banks (BLH) are a strategy to increase breastfeeding coverage; the donated milk is subjected to Holder pasteurization to guarantee its innocuousness, undergoing large changes in temperature and a decrease in the concentrations of biocomponents such as Immunoglobulin A (IgA) and lactoferrin (LF). This article describes the results of recent studies on the impact of Holder pasteurization on IgA and LF in human milk.

MATERIAL AND METHODS

a search for research articles related to the topic of interest was carried out in various databases and in accordance with inclusion criteria that considered the type of study, date of publication and quality of the journal.

RESULTS

the impact of Holder pasteurization on IgA and LF concentrations is not clear, given that the literature reports a variety of protocols and different results; however, the percentage reductions of both biocomponents are significant and consistent in the studies reviewed, suggesting the importance of establishing a standard protocol for their quantification.

CONCLUSIONS

Holder pasteurization guarantees the microbiological quality of the milk distributed in HMB, but affects the amount of beneficial biocomponents for the final recipient. Government entities that regulate HMBs should evaluate the possibility of using other techniques that reduce the impact on biocomponents while preserving the microbiological quality of the product.

Association between dairy consumption and the risk of diabetes: A prospective cohort study from the China Health and Nutrition Survey

Diet is closely related to the risk of diabetes; yet the relationship between dairy consumption and the risk of diabetes is unclear with conflicting evidence from previous studies. This study used data from the Chinese Health and Nutrition Survey to investigate the association between dairy consumption and diabetes. A total of 15,512 adults were included; dairy consumption at each survey was assessed by the 3-day 24-h recall and weighed food record methods, and diabetes occurrence was derived from self-reported information. The association between dairy consumption and diabetes was explored using Cox regression and further stratified with BMI and energy intake. Results indicated that 12,368 (79.7%) participants had no dairy consumption, while 2,179 (14.0%) and 947 (6.1%) consumed dairy at 0.1-100 and >100 g/day, respectively. After adjusting for potential confounders, dairy consumption of 0.1-100 g/day was associated with lower risk of diabetes in all participants (HR 0.53, 95% CI:0.38 -0.74; P < 0.001) and males (HR 0.50, 95% CI: 0.31-0.80; P = 0.004). According to the restricted cubic splines (RCS), the protective effect on diabetes was significant in the total population with dairy consumption ranging from 25 to 65 g/day (HR <1, P = 0.025). In the stratified analysis, consuming 30-80 g/day was associated with reduced diabetes risk among the ≤ 2,000 kcal/day energy intake group (HR <1, P = 0.023). In conclusion, dairy consumption was inversely associated with a reduced diabetes risk in Chinese population. Further studies are required to examine the optimal level of dairy consumption for preventing diabetes in the Chinese population.

A Comprehensive Review of the Composition, Nutritional Value, and Functional Properties of Camel Milk Fat

Recently, camel milk (CM) has been considered as a health-promoting icon due to its medicinal and nutritional benefits. CM fat globule membrane has numerous health-promoting properties, such as anti-adhesion and anti-bacterial properties, which are suitable for people who are allergic to cow's milk. CM contains milk fat globules with a small size, which accounts for their rapid digestion. Moreover, it also comprises lower amounts of cholesterol and saturated fatty acids concurrent with higher levels of essential fatty acids than cow milk, with an improved lipid profile manifested by reducing cholesterol levels in the blood. In addition, it is rich in phospholipids, especially plasmalogens and sphingomyelin, suggesting that CM fat may meet the daily nutritional requirements of adults and infants. Thus, CM and its dairy products have become more attractive for consumers. In view of this, we performed a comprehensive review of CM fat's composition and nutritional properties. The overall goal is to increase knowledge related to CM fat characteristics and modify its unfavorable perception. Future studies are expected to be directed toward a better understanding of CM fat, which appears to be promising in the design and formulation of new products with significant health-promoting benefits.

Precision medicine in cow's milk allergy: proteomics perspectives from allergens to patients

Cow's milk allergy (CMA) is one of the most common food allergies, especially during childhood. CMA is an immunological mediated adverse reaction to one or more cow's milk proteins, which are normally harmless to a non-allergic individual, as the result of a failure of oral tolerance. To make a correct diagnosis of CMA and a proper treatment is critical in clinical practice. Application of proteomics along with new bio-informatics tools in the field of food allergy is one of the hot topics presented in recent years. In the present review, we focus on recent applications of proteomics to the field of cow's milk allergy, from allergens quantification to the diagnosis, treatment and prognosis. Furthermore, we also shed a light on potential future directions and developments, that are parts of personalized medicine but also of the One Health approach.

SIGNIFICANCE

The field of food allergies is becoming a milestone in public health. Food allergies, in fact, can cause life-threatening reactions and profoundly influence the quality of life. Precise, fast and reliable diagnosis of food allergies, and in particular milk allergies is essential to avoid severe allergic reactions and also to prevent dangerous and eventually unnecessary dietary restrictions; but this can be difficult also due to a complex interaction of genetic background, environment, and microbiota. In this sense, proteomics represents steps toward researching food and milk allergy integrated with the clinic to improve pathophysiology, diagnosis, therapy, and prognosis.

Epidemiological pattern of newly diagnosed children with type 1 diabetes mellitus, Taif, Saudi Arabia

INTRODUCTION AND AIM

Type-1-diabetes mellitus (T1DM) is the most commonly diagnosed type of DM in children and adolescents. We aim to identify the epidemiological profile, risk factors, clinical features, and factors related to delayed diagnosis or mismanagement in children with newly diagnosed T1DM in Taif, Saudi Arabia.

PATIENTS AND METHODS

Ninety-nine newly diagnosed patients were included in the study along with 110 healthy controls. Patients were classified into 3 groups (I: >2 years, II: 2->6 years, and III: 6-12 years). Both patients and controls were tested for C-peptide, TSH, and autoantibodies associated with DM and those attacking the thyroid gland.

RESULTS

Diabetic ketoacidosis was present in 79.8%. Delayed and missed diagnoses were recorded in 45.5%, with significant correlation to age and district of origin. Severity at presentation showed significant correlation with age and cow's milk feeding. Group I, those with misdiagnosis or positive DM related autoantibodies, had more severe presentations. The correlation of C-peptide and TSH levels in patients and controls was significant for C-peptide and nonsignificant for TSH.

CONCLUSION

Misdiagnosis and mismanagement are common and account for more severe presentation, especially in young children >2 years. Early introduction of cow's milk appears to be a risk factor for the development of T1DM.

A whey protein hydrolysate promotes insulinotropic activity in a clonal pancreatic β-cell line and enhances glycemic function in ob/ob mice

Whey protein hydrolysates (WPHs) represent novel antidiabetic agents that affect glycemia in animals and humans, but little is known about their insulinotropic effects. The effects of a WPH were analyzed in vitro on acute glucose-induced insulin secretion in pancreatic BRIN-BD11 β cells. WPH permeability across Caco-2 cell monolayers was determined in a 2-tiered intestinal model. WPH effects on insulin resistance were studied in vivo following an 8-wk oral ingestion (100 mg/kg body weight) by ob/ob (OB-WPH) and wild-type mice (WT-WPH) compared with vehicle control (OB and WT groups) using a 2 × 2 factorial design, genotype × treatment. BRIN-BD11 cells showed a robust and reproducible dose-dependent insulinotropic effect of WPH (from 0.01 to 5.00 g/L). WPH bioactive constituents were permeable across Caco-2 cell monolayers. In the OB-WPH and WT-WPH groups, WPH administration improved glucose clearance after a glucose challenge (2 g/kg body weight), as indicated by differences in the area under curves (AUCs) (P ≤ 0.05). The basal plasma glucose concentration was not affected by WPH treatment in either genotype. The plasma insulin concentration was lower in the OB-WPH than in the OB group (P ≤ 0.005) but was similar between the WT and WT-WPH groups; the interaction genotype × treatment was significant (P ≤ 0.005). Insulin release from pancreatic islets isolated from the OB-WPH group was greater (P ≤ 0.005) than that from the OB group but did not differ between the WT-WPH and WT groups; the interaction genotype × treatment was not significant. In conclusion, an 8-wk oral administration of WPH improved blood glucose clearance, reduced hyperinsulinemia, and restored the pancreatic islet capacity to secrete insulin in response to glucose in ob/ob mice. Hence, it may be useful in diabetes management.

Analysis of insulin in human breast milk in mothers with type 1 and type 2 diabetes mellitus

Despite the important role that insulin plays in the human body, very little is known about its presence in human milk. Levels rapidly decrease during the first few days of lactation and then, unlike other serum proteins of similar size, achieve comparable levels to those in serum. Despite this, current guides for medical treatment suggest that insulin does not pass into milk, raising the question of where the insulin in milk originates. Five mothers without diabetes, 4 mothers with type 1, and 5 mothers with type 2 diabetes collected milk samples over a 24-hour period. Samples were analysed for total and endogenous insulin content and for c-peptide content. All of the insulin present in the milk of type 1 mothers was artificial, and c-peptide levels were 100x lower than in serum. This demonstrates that insulin is transported into human milk at comparable concentration to serum, suggesting an active transport mechanism. The role of insulin in milk is yet to be determined; however, there are a number of potential implications for the infant of the presence of artificial insulins in milk.

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

BACKGROUND/OBJECTIVES

N-3 (omega-3) fatty acids have been reported to decrease the risk for development of beta-cell autoimmunity and clinical type I diabetes. We set out to examine whether different serum fatty acids are associated with the development of advanced beta-cell autoimmunity in children carrying human leukocyte antigen DQ beta-1 (HLA-DQB1)-conferred susceptibility to type I diabetes.

SUBJECTS/METHODS

Within a cohort, serum total fatty acid composition of 108 children with advanced beta-cell autoimmunity and of 216 matched persistently autoantibody-negative controls was analyzed using gas chromatography. Non-fasting serum samples were obtained annually at the ages of 1-6 years. Conditional logistic regression was applied to analyze the associations between advanced beta-cell autoimmunity and serum fatty acids.

RESULTS

The serum fatty acid profile of myristic acid (odds ratio (OR) 1.48, 95% confidence interval (CI) 1.09-2.00, P=0.011), pentadecanoic acid (OR 1.65, 95% CI 1.19-2.28, P=0.003), palmitoleic acid isomers 16:1 n-7 (omega-7) (OR 1.41, 95% CI 1.03-1.92, P=0.030) and 16:1 n-9 (omega-9) (OR 1.45, 95% CI 1.05-2.01, P=0.026) and conjugated linoleic acid (OR 1.67, 95% CI 1.16-2.41, P=0.006) closest to the time of the appearance of multiple autoantibodies were positively associated with the risk of advanced beta-cell autoimmunity after adjustment for potential confounding factors. Serum linoleic acid showed inverse, marginal association with the end point.

CONCLUSIONS

Serum biomarkers of milk and ruminant meat fat consumption are directly associated and linoleic acid is inversely associated with advanced beta-cell autoimmunity in children with HLA-conferred susceptibility to type I diabetes.

Review series on helminths, immune modulation and the hygiene hypothesis: how might infection modulate the onset of type 1 diabetes?

The development of type 1 diabetes is influenced by both genetic and environmental factors. The current rise in the incidence of diabetes is occurring more rapidly than can be accounted for by genetic change, highlighting the influence of environmental modifiers. Considerable effort has been expended to identify infectious agents that might be responsible for this rise in incidence, but no single infectious agent has been linked to this dramatic increase in type 1 diabetes. There has been increasing interest in the possibility that infections of historical importance that might have shaped our immune systems over evolutionary time may also have played a role in down-modulating some autoimmune and allergic disorders. In this review, some of the ways in which certain organisms might have influenced the onset of autoimmunity are discussed.

Effects of uteroplacental insufficiency and reducing litter size on maternal mammary function and postnatal offspring growth

Human intrauterine growth restriction is often associated with uteroplacental insufficiency and a decline in nutrient and oxygen supply to the fetus. This study investigated the effects of uteroplacental insufficiency and intrauterine growth restriction (Restricted) or reducing litter size for normally grown pups (Reduced Litter) on maternal mammary development and function, milk composition, offspring milk intake, and their resultant effects on postnatal growth. Uteroplacental insufficiency was surgically induced by bilateral uterine vessel ligation on day 18 of gestation in the Wistar Kyoto rat. At birth, a group of sham control rats had their litter size reduced to five (Reduced Litter) to match that of the Restricted group. Cohorts of rats were terminally anesthetized on day 20 of gestation or day 6 of lactation, and a third group was studied throughout lactation. Restricted pups had a lower birth weight (by 16%) and litter size (by 36%) compared with controls, as well as reduced mammary parathyroid hormone-related protein content and milk ionic calcium concentrations associated with reduced total pup calcium. Restricted dams with lower circulating progesterone experienced premature lactogenesis, producing less milk per pup with altered composition compared with controls, further slowing growth during lactation. Reducing litter size of pups born of normal birth weight (Reduced Litter) was associated with decreased pup growth, highlighting the importance of appropriate controls. The present study demonstrates that uteroplacental insufficiency impairs mammary function, compromises milk quality and quantity, and reduces calcium transport into milk, further restraining postnatal growth.

On the supposed influence of milk homogenization on the risk of CVD, diabetes and allergy

Commercial milk is homogenized for the purpose of physical stability, thereby reducing fat droplet size and including caseins and some whey proteins at the droplet interface. This seems to result in a better digestibility than untreated milk. Various casein peptides and milk fat globule membrane (MFGM) proteins are reported to present either harmful (e.g. atherogenic) or beneficial bioactivity (e.g. hypotensive, anticarcinogenic and others). Homogenization might enhance either of these effects, but this remains controversial. The effect of homogenization has not been studied regarding the link between early cow's milk consumption and occurrence of type I diabetes in children prone to the disease and no link appears in the general population. Homogenization does not influence milk allergy and intolerance in allergic children and lactose-intolerant or milk-hypersensitive adults. The impact of homogenization, as well as heating and other treatments such as cheesemaking processes, on the health properties of milk and dairy products remains to be fully elucidated.

Metabolic and genomic dissection of diabetes in the Cohen rat

We investigated the metabolic and genetic basis of diabetes in the Cohen Diabetic rat, a model of diet-induced diabetes, as a means to identify the molecular mechanisms involved. By altering individual components in the diabetogenic diet, we established that the dietary susceptibility that leads to the development of diabetes in this model is directly related to the high casein and low copper content in chow. The development of diabetes is accompanied by depletion of the acini from the exocrine pancreas and replacement with fat cells, while the appearance of the islets of Langerhans remains intact. With reversion back from diabetogenic to regular diet, the diabetic phenotype disappears but the histological changes in the exocrine pancreas prevail. Using positional cloning, we detected a major quantitative trait locus (QTL) on rat chromosome 4 with a chromosomal span of 4.9 cM, and two additional loci on chromosomes 7 and X. A screen for genes within that QTL in the rat and in the syntenic regions in mouse and man revealed only 23 candidate genes. Notable among these genes is Ica1, which has been causally associated with diabetes and bovine casein. We conclude that the development of diabetes in our model is dependent upon high casein and low copper in diet, that it is accompanied by histomorphological changes in the exocrine but not endocrine pancreas, that it is reversible, and that it is associated with a major QTL on chromosome 4 in which we detected Ica1, a high priority candidate gene.

Current status of pancreatic islet transplantation

DM (diabetes mellitus) is a metabolic disorder of either absolute or relative insulin deficiency. Optimized insulin injections remain the mainstay life-sustaining therapy for patients with T1DM (Type I DM) in 2006; however, a small subset of patients with T1DM (approx. 10%) are exquisitely sensitive to insulin and lack counter-regulatory measures, putting them at higher risk of neuroglycopenia. One alternative strategy to injected insulin therapy is pancreatic islet transplantation. Islet transplantation came of age when Paul E. Lacy successfully reversed chemical diabetes in rodent models in 1972. In a landmark study published in 2000, Shapiro et al. [A. M. Shapiro, J. R. Lakey, E. A. Ryan, G. S. Korbutt, E. Toth, G. L. Warnock, N. M. Kneteman and R. V. Rajotte (2000) N. Engl. J. Med. 343, 230-238] reported seven consecutive patients treated with islet transplants under the Edmonton protocol, all of whom maintained insulin independence out to 1 year. Substantial progress has occurred in aspects of pancreas procurement, transportation (using the oxygenated two-layer method) and in islet isolation (with controlled enzymatic perfusion and subsequent digestion in the Ricordi chamber). Clinical protocols to optimize islet survival and function post-transplantation improved dramatically with the introduction of the Edmonton protocol, but it is clear that this approach still has potential limitations. Newer pharmacotherapies and interventions designed to promote islet survival, prevent apoptosis, to promote islet growth and to protect islets in the long run from immunological injury are rapidly approaching clinical trials, and it seems likely that clinical outcomes of islet transplantation will continue to improve at the current exponential pace.

Glutathione-s-transferase M1 and T1 polymorphisms and associations with type 1 diabetes age-at-onset

Type 1 diabetes (T1D) is an autoimmune disease characterized by pancreatic beta cell destruction involving auto-reactive T-cells, pro-inflammatory cytokines, reactive oxygen species (ROS) and loss of insulin. Monozygotic twin studies show a 20-60% concordance with T1D indicating there may be an environmental component to the disease. Glutathione (GSH) is the major endogenous antioxidant produced by the cell. GSH participates directly in the neutralization of free radicals and plays a role in the immune response. Glutathione-s-transferases (GSTs) conjugate GSH to free-radicals or xenobiotics. GST activity depletes GSH levels and may either detoxify or enhance the toxicity of a compound. Glutathione-s-transferase mu 1 (GSTM1) and glutathione-s-transferase theta 1 (GSTT1) have polymorphic homozygous deletion (null) genotypes resulting in complete absence of enzyme activity. GSTM1 and GSTT1 null genotypes in Caucasian populations have frequencies of approximately 40-60% and 15-20%, respectively. GST null genotypes have been associated with susceptibility to cancer and protection against chronic pancreatitis. The aim of this study was to investigate associations with GSTM1 and GSTT1 polymorphisms in a group T1D patients and control subjects 0-35 years old who participated in the Combined Swedish Childhood Diabetes Registry and Diabetes Incidence Study (1986-1988). Results show that the presence of the GSTM1 and not the null genotype (OR, 2.13 95% CI, 1.23-3.70, p-value, 0.007, Bonferroni corrected p-value, 0.035) may be a susceptibility factor in T1D 14-20 years old. These results suggest that the GSTM1 null genotype is associated with T1D protection and T1D age-at-onset and that susceptibility to T1D may involve GST conjugation.

Gene therapy for type 1 diabetes

The most intensively studied autoimmune disorder, type 1 diabetes mellitus (DM1), has attracted perhaps the greatest interest for gene-based therapeutic and prophylactic interventions. The final clinical manifestation of this immunologically and genetically complex disease, the absence of insulin, is the major starting point for almost all the gene therapy modalities attempted to date. Insulin replacement by transplantation of islets of Langerhans or surrogate beta cells is the obvious choice, but the allogeneic nature of the transplants activates potent antidonor immunoreactivity necessitating gene and cell-based immunosuppressive strategies as an alternative to the toxic pharmacologic immunosuppressives indicated for classic solid organ transplants. Accumulating knowledge of the cellular mechanisms involved in onset, however, have yielded promising tolerance induction prophylactic approaches using genes and cells. Despite the early successes in a number of animal models, the true test of efficacy in humans remains to be demonstrated.

Lower consumption of cow milk protein A1 beta-casein at 2 years of age, rather than consumption among 11- to 14-year-old adolescents, may explain the lower incidence of type 1 diabetes in Iceland than in Scandinavia

AIM

To compare the consumption of the cow milk proteins A1 and B beta-casein among children and adolescents in Iceland and Scandinavia (Norway, Denmark, Sweden and Finland) as this might explain the lower incidence of type 1 diabetes (per 100,000/year, 0-14 years) in Iceland.

METHODS

The consumption of A1 beta-casein in each country among 2- and 11- to 14-year-old children was calculated from results on food intake and on cow milk protein concentration. The consumption values were then compared and evaluated against the incidence of type 1 diabetes.

RESULTS

There was a significant difference between the consumption of A1 (p = 0.034) as well as the sum of A1 and B (p = 0.021) beta-casein in Iceland and Scandinavia for 2-year-old children. In the same age group, consumption of A1 beta-casein correlated with the incidence of type 1 diabetes in the countries (r = 0.9; p = 0.037). No significant difference in consumption of A1 or the sum of A1 and B beta-casein was found for 11- to 14-year-old adolescents.

CONCLUSION

This study supports that lower consumption of A1 beta-casein might be related to the lower incidence of type 1 diabetes in Iceland than in Scandinavia. Additionally it indicates that consumption in young childhood might be of more importance for the development of the disease incidence than consumption in adolescence.

A Systematic Review of the Literature Associating Breastfeeding with Type 2 Diabetes and Gestational Diabetes

As diabetes becomes more prevalent in younger women, diabetes and maternal-child health issues such as breastfeeding co-exist with increasing frequency. We sought to determine the relationship between breastfeeding and both type 2 diabetes and gestational diabetes (GDM) in a variety of clinical contexts, with a focus on prevention. The Medline database from 1966-2003, relevant references of selected articles, the Cochrane database, and the NIH Clinical Trials website were searched. Search terms included breastfeeding, infant nutrition, and diabetes. The search was restricted to the English language and human subjects. Each study was reviewed by at least two of the authors and included if it pertained to the relationship between type 2 diabetes or GDM and breastfeeding. Twelve of 15 identified studies (80%) met selection criteria. All studies were observational. Specific maternal-child health populations varied by study. Two of the authors abstracted information from each article on 1) study design, 2) target population, 3) sample size/power, 4) definition of breastfeeding, 5) definition of diabetes, and 6) confounders. Higher rates of pregnancy and neonatal complications among women with type 2 or gestational diabetes can pose significant challenges to breastfeeding. Low estrogen levels in breastfeeding women may have a protective effect on glucose metabolism and subsequent risk of diabetes. Having been breastfed for at least 2 months may lower the risk of diabetes in children. Initial research has begun on the long-term effects of diabetes during pregnancy on children. Breastfeeding may lower both maternal and pediatric rates of diabetes. Women with diabetes should be strongly encouraged to breastfeed because of maternal and childhood benefits specific to diabetes that are above and beyond other known benefits of breastfeeding.

High intakes of milk, but not meat, increase s-insulin and insulin resistance in 8-year-old boys

OBJECTIVE

Our objective was to examine if a high animal protein intake from milk or meat increased s-insulin and insulin resistance in healthy, prepubertal children. A high animal protein intake results in higher serum branched chain amino acids (BCAA; leucine, isoleucine and valine) concentrations, which are suggested to stimulate insulin secretion. Furthermore, milk possesses some postprandial insulinotrophic effect that is not related to its carbohydrate content.

DESIGN

A total of 24 8-y-old boys were asked to take 53 g protein as milk or meat daily. At baseline and after 7 days, diet was registered, and insulin, glucose, and amino acids were determined. Insulin resistance and beta cell function were calculated with the homeostasis model assessment.

RESULTS

Protein intake increased by 61 and 54% in the milk- and meat-group, respectively. In the milk-group, fasting s-insulin concentrations doubled, which caused the insulin resistance to increase similarly. In the meat-group, there was no increase in insulin and insulin resistance. As the BCAAs increased similarly in both groups, stimulation of insulin secretion through BCAAs is not supported.

CONCLUSIONS

Our results indicate that a short-term high milk, but not meat, intake increased insulin secretion and resistance. The long-term consequences of this are unknown. The effect of high protein intakes from different sources on glucose-insulin metabolism needs further studying.

Avoiding milk is associated with a reduced risk of insulin resistance and the metabolic syndrome: findings from the British Women's Heart and Health Study

OBJECTIVE

To examine the association of milk consumption with insulin resistance and the metabolic syndrome.

METHODS

The association was examined in 4024 British women aged 60-79 who were randomly selected from primary care centres in 23 towns.

RESULTS

Women who never drank milk had lower homeostasis model assessment insulin resistance (HOMA) scores, triglyceride concentrations and body mass indices, and higher high-density lipoprotein (HDL)-cholesterol concentrations, than those who drank milk. The age-adjusted odds ratio for the metabolic syndrome comparing non-milk drinkers with drinkers was 0.55 (0.33, 0.94), which did not attenuate with adjustment for potential confounders. Diabetes was less common in non-milk drinkers.

CONCLUSION

Individuals who do not drink milk may be protected against insulin resistance and the metabolic syndrome. However, randomized controlled trials are required to establish whether milk avoidance is causally associated with these outcomes.

A perinatal strategy to prevent coronary heart disease

I investigated whether metabolism of essential fatty acids and the concentrations of their long-chain metabolites (long-chain polyunsaturated fatty acids [LCPUFAs]) are altered in fetal or perinatal growth retardation, maternal hypercholesterolemia, low-grade systemic inflammation, insulin resistance, and atherosclerosis, conditions that predispose to the development of coronary heart disease (CHD).I critically reviewed the literature pertaining to the metabolism of essential fatty acids in CHD and conditions that predispose to it.LCPUFAs enhance endothelial nitric oxide synthesis, suppress the production of the proinflammatory cytokines tumor necrosis factor and interleukin-6, attenuate insulin resistance, and have antiatherosclerotic properties. Low-birthweight infants have decreased concentrations of LCPUFAs, especially arachidonic acid. Neonatal arachidonic acid status is related to intrauterine growth, and LCPUFAs improve fetal and postnatal growth. LCPUFAs are useful in the management of hyperlipidemia, inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, and may mediate the beneficial actions of statins. Plasma concentrations of various LCPUFAs are low in diabetes mellitus, hypertension, and CHD and in populations at high risk of CHD. Breast milk is rich in LCPUFAs, and this may explain why and how adequate (6 mo to 1 y) breast feeding protects against the development of obesity, hypertension, insulin resistance, and CHD.LCPUFAs are essential for the growth and development of the fetus and infant. LCPUFAs can prevent various conditions that predispose to the development of CHD. The low incidence of CHD seen in adequately breast-fed infants can be linked to the LCPUFA content of breast milk. Based on this evidence, I suggest that provision of LCPUFAs during critical periods of growth, especially from the second trimester of pregnancy to age 5 y, prevents CHD in adult life.

Long-chain polyunsaturated fatty acids and chemically induced diabetes mellitus. Effect of omega-3 fatty acids

In a previous study, we showed that prior oral feeding of oils rich in omega-3 eicosapentaenoic acid and docosahexaenoic acid and omega-6 gamma-linolenic acid and arachidonic acid prevent the development of alloxan-induced diabetes mellitus in experimental animals. We also observed that 99% pure omega-6 fatty acids gamma-linolenic acid and arachidonic acid protect against chemically induced diabetes mellitus. Here we report the results of our studies with omega-3 fatty acids. Alloxan-induced in vitro cytotoxicity and apoptosis in an insulin-secreting rat insulinoma cell line, RIN, was prevented by prior exposure of these cells to alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid. Prior oral supplementation with alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid prevented alloxan-induced diabetes mellitus. alpha-Linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid not only attenuated chemical-induced diabetes mellitus but also restored the anti-oxidant status to normal range in various tissues. These results suggested that omega-3 fatty acids can abrogate chemically induced diabetes in experimental animals and attenuate the oxidant stress that occurs in diabetes mellitus.

Long-chain polyunsaturated fatty acids and chemically induced diabetes mellitus: effect of omega-6 fatty acids

OBJECTIVE

We previously showed that prior oral supplementation of oils rich in omega-3, eicosapentaenoic acid and docosahexaenoic acid, and omega-6, gamma-linolenic acid and arachidonic acid, can prevent the development of alloxan-induced diabetes mellitus in experimental animals. But the effect of individual fatty acids on chemically induced diabetes mellitus is not known. We report the results of our studies with omega-6 fatty acids.

METHODS

Alloxan-induced in vitro cytotoxicity and apoptosis in an insulin-secreting rat insulinoma cell line, RIN, was prevented by prior exposure of these cells to linoleic acid, gamma-linolenic acid, and arachidonic acid (AA) but not to dihomo-gamma-linolenic acid. Cyclo-oxygenase and lipoxygenase inhibitors did not block this protective action of AA. Prior oral supplementation with gamma-linolenic acid and pre- and simultaneous treatments with AA prevented alloxan-induced diabetes mellitus.

RESULTS

Even though pretreatment with linoleic acid and dihomo-gamma-linolenic acid and simultaneous treatment with linoleic acid, gamma-linolenic acid, and dihomo-gamma-linolenic acid did not prevent the development of diabetes mellitus, the severity of diabetes was much less. The saturated fatty acid stearic acid and the monounsaturated fatty acid oleic acid were ineffective in preventing alloxan-induced diabetes mellitus. gamma-Linolenic acid and AA not only attenuated chemically induced diabetes mellitus but also restored the antioxidant status to normal range in various tissues. Changes in the concentrations of various fatty acids of the phospholipid fraction of plasma that occurred as a result of alloxan-induced diabetes mellitus also reverted to normal in the AA-treated animals.

CONCLUSIONS

These results suggest that polyunsaturated fatty acids can prevent chemically induced diabetes in experimental animals and attenuate the oxidant stress that occurs in diabetes mellitus.

Can perinatal supplementation of long-chain polyunsaturated fatty acids prevent diabetes mellitus?

It is suggested that the negative correlation between breast-feeding and insulin resistance and diabetes mellitus can be related to the presence of significant amounts of long-chain polyunsaturated fatty acids in the human breast milk. Based on this, it is proposed that provision of adequate amounts of long chain polyunsaturated fatty acids during the critical periods of brain growth and development can prevent or postpone the development diabetes mellitus.

Is type 2 diabetes mellitus a disorder of the brain?

I propose that type 2 diabetes mellitus is due to damage to neurons in the ventromedial hypothalamus or to a defect in the action or properties of insulin or insulin receptors in the brain. These neuronal abnormalities are probably secondary to a marginal deficiency of long-chain polyunsaturated fatty acids during the critical periods of brain growth and development. Hence, supplementation of adequate amounts of long-chain polyunsaturated fatty acids during the third trimester of pregnancy to 2 y postterm can prevent or postpone the development of diabetes mellitus.

The lipids that matter from infant nutrition to insulin resistance

Breast-fed infants showed decreased incidence of obesity, hypertension, diabetes mellitus, and coronary heart disease in later life and higher cognitive function. Breast milk is rich in long-chain polyunsaturated fatty acids (LCPUFAs) and brain preferentially accumulates LCPUFAs during the last trimester of pregnancy and the first few months of life. Breast-fed infants showed significantly lower plasma glucose levels and higher percentage of docosahexaenoic acid and total percentages of LCPUFAs in their skeletal muscle biopsies compared with formula fed. LCPUFAs suppress the production of pro-inflammatory cytokines, regulate the function of several neurotransmitters, enhance the number of insulin receptors in the brain and other tissues, and decrease insulin resistance. LCPUFAs may enhance the production of bone morphogenetic proteins (BMPs), which participate in neurogenesis. It is proposed that the beneficial effects of breast feeding in later life can be attributed to its rich LCPUFA content. It is likely that inadequate breast feeding results in marginal deficiency of LCPUFAs during the critical stages of development, which can lead to insulin resistance. Hence, promoting prolonged breast feeding and/or supplementing LCPUFAs during the critical stages of development may be beneficial in preventing insulin resistance.

Update on host defense and immunonutrients

Neonatal intensive care in the past three decades has provided exciting modalities for improving the survival of critically ill neonates. There remains a great need for improving the quality of life for these survivors. In this article, the role the developing GI tract and its microenvironment play in the well-being of the neonate has been emphasized. Future therapies based on manipulation of the GI tract and its microenvironment by functional foods, immunonutrients, or pharmacologic agents may have effects not only during the neonatal period, but also throughout the individual's entire life.

Translating data from animal models into methods for preventing human autoimmune diabetes mellitus: caveat emptor and primum non nocere

Type 1 diabetes in humans is a serious autoimmune disorder of children that is still poorly understood, unpreventable, and irreversible. Study of its animal models, notably the NOD mouse and BB rat, has generated a wealth of information concerning genetics and immunopathogenesis, but that information has still not altered the way in which we treat children with diabetes. In this review we attempt to identify the most promising avenues of continuing research in these models and the most important issues that must be faced by the designers of human therapies based on the animal dataset.