Vitamin C attenuation of the development of type I diabetes mellitus by interferon-alpha

Maternal Vitamin C and Iron Intake during Pregnancy and the Risk of Islet Autoimmunity and Type 1 Diabetes in Children: A Birth Cohort Study

Our aim was to study the associations between maternal vitamin C and iron intake during pregnancy and the offspring’s risk of developing islet autoimmunity and type 1 diabetes. The study was a part of the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) prospective birth cohort including children genetically at risk of type 1 diabetes born between 1997–2004. The diets of 4879 mothers in late pregnancy were assessed with a validated food frequency questionnaire. The outcomes were islet autoimmunity and type 1 diabetes. Cox proportional hazards regression analysis adjusted for energy, family history of diabetes, human leukocyte antigen (HLA) genotype and sex was used for statistical analyses. Total intake of vitamin C or iron from food and supplements was not associated with the risk of islet autoimmunity (vitamin C: HR 0.91: 95% CI (0.80, 1.03), iron: 0.98 (0.87, 1.10)) or type 1 diabetes (vitamin C: 1.01 (0.87, 1.17), iron: 0.92 (0.78, 1.08)), neither was the use of vitamin C or iron supplements associated with the outcomes. In conclusion, no association was found between maternal vitamin C or iron intake during pregnancy and the risk of islet autoimmunity or type 1 diabetes in the offspring.

Plasma ascorbic acid and the risk of islet autoimmunity and type 1 diabetes: the TEDDY study

AIMS/HYPOTHESIS

We studied the association of plasma ascorbic acid with the risk of developing islet autoimmunity and type 1 diabetes and examined whether SNPs in vitamin C transport genes modify these associations. Furthermore, we aimed to determine whether the SNPs themselves are associated with the risk of islet autoimmunity or type 1 diabetes.

METHODS

We used a risk set sampled nested case-control design within an ongoing international multicentre observational study: The Environmental Determinants of Diabetes in the Young (TEDDY). The TEDDY study followed children with increased genetic risk from birth to endpoints of islet autoantibodies (350 cases, 974 controls) and type 1 diabetes (102 cases, 282 controls) in six clinical centres. Control participants were matched for family history of type 1 diabetes, clinical centre and sex. Plasma ascorbic acid concentration was measured at ages 6 and 12 months and then annually up to age 6 years. SNPs in vitamin C transport genes were genotyped using the ImmunoChip custom microarray. Comparisons were adjusted for HLA genotypes and for background population stratification.

RESULTS

Childhood plasma ascorbic acid (mean ± SD 10.76 ± 3.54 mg/l in controls) was inversely associated with islet autoimmunity risk (adjusted OR 0.96 [95% CI 0.92, 0.99] per +1 mg/l), particularly islet autoimmunity, starting with insulin autoantibodies (OR 0.94 [95% CI 0.88, 0.99]), but not with type 1 diabetes risk (OR 0.93 [95% Cl 0.86, 1.02]). The SLC2A2 rs5400 SNP was associated with increased risk of type 1 diabetes (OR 1.77 [95% CI 1.12, 2.80]), independent of plasma ascorbic acid (OR 0.92 [95% CI 0.84, 1.00]).

CONCLUSIONS/INTERPRETATION

Higher plasma ascorbic acid levels may protect against islet autoimmunity in children genetically at risk for type 1 diabetes. Further studies are warranted to confirm these findings.

DATA AVAILABILITY

The datasets generated and analysed during the current study will be made available in the NIDDK Central Repository at https://www.niddkrepository.org/studies/teddy.

Intake of antioxidant vitamins and trace elements during pregnancy and risk of advanced beta cell autoimmunity in the child

BACKGROUND

Type 1 diabetes may have its origins in the fetal period of life. Free radicals were implicated in the cause of type 1 diabetes. It was hypothesized that antioxidant nutrients could protect against type 1 diabetes.

OBJECTIVE

We assessed whether high maternal intake of selected dietary antioxidants during pregnancy is associated with a reduced risk of advanced beta cell autoimmunity in the child, defined as repeated positivity for islet cell antibodies plus >/=1 other antibody, overt type 1 diabetes, or both.

DESIGN

The study was carried out as part of the population-based birth cohort of the Type 1 Diabetes Prediction and Prevention Project. The data comprised 4297 children with increased genetic susceptibility to type 1 diabetes, born at the University Hospital of Oulu or Tampere, Finland, between October 1997 and December 2002. The children were monitored for diabetes-associated autoantibodies from samples obtained at 3-12-mo intervals. Maternal antioxidant intake during pregnancy was assessed postnatally with a self-administered food-frequency questionnaire, which contained a question about consumption of dietary supplements.

RESULTS

Maternal intake of none of the studied antioxidant nutrients showed association with the risk of advanced beta cell autoimmunity in the child. The hazard ratios, indicating the change in risk per a 2-fold increase in the intake of each antioxidant, were nonsignificant and close to 1.

CONCLUSION

High maternal intake of retinol, beta-carotene, vitamin C, vitamin E, selenium, zinc, or manganese does not protect the child from development of advanced beta cell autoimmunity in early childhood.

Interrelationship of antioxidative status, lipid peroxidation, and lipid profile in insulin-dependent and non-insulin-dependent diabetic patients

This study aimed to investigate the interrelationship of plasma lipid profile, lipid peroxidation, and erythrocyte antioxidative defense in patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. Plasma levels of total cholesterol, triglycerides, and lipid peroxides and the activities of copper, zinc superoxide dismutase (CuZnSOD), catalase, glutathione peroxidase (GSH-Px), as well as the amount of glutathione in erythrocytes, were determined in IDDM, NIDDM, and nondiabetic control subjects. Additionally, morphology of erythrocytes in all subjects was examined. Plasma levels of total cholesterol and triglycerides were significantly increased in NIDDM compared with controls. Also, the lipid peroxide level was higher in NIDDM than in either control or IDDM subjects. CuZnSOD activity in erythrocytes was elevated in NIDDM patients compared with the control. In NIDDM patients, more extensive erythrocyte spherocytosis and echinocytosis compared with both control and IDDM subjects were observed. In contrast with the IDDM group, the observed abnormality in lipid metabolism in NIDDM patients is closely associated with increased lipid peroxidation, changes in antioxidative defense, and erythrocyte morphology.

Why diabetes incidence increases--a unifying theory

There is a wide spectrum within the diabetes syndrome. Type 1 diabetes may have a slow progression with good residual insulin secretion and without autoantibodies, while phenotypic type 2 diabetes may have autoantibodies. A single patient may have traits of both types of diabetes. Their incidence increases in parallel. The etiology is mainly unknown, but environmental factors play an important role in genetically predisposed individuals. The search for just one single cause of manifest diabetes may be confusing. Different mechanism may be important in different parts of the world. Furthermore, certain mechanisms may lead to islet inflammation while other/additional mechanisms may increase insulin demand and cause insulin deficiency with manifestation of clinical diabetes. Several hypothesis of etiology may fit different parts of the disease process. Thus, increased hygiene may contribute to an imbalance of the immune system, facilitating autoimmune reactions when virus infections, or proteins like cow's milk or gluten, provoke. Increased insulin demand because of rapid growth, or insulin resistance caused by stress, infections, puberty, etc., lead to beta cell stress, antigen presentation and may cause both an autoimmune reaction in genetically predisposed individuals, and insulin deficiency leading to manifest diabetes in individuals who have lost beta cell function. Vitamins may modulate the immune process, but we know too little to give vitamin substitution. However, we do know that low physical exercise, obesity, and stress, increases insulin demand resulting in insulin deficiency. Now we can therefore intervene to prevent the diabetic syndrome.

Protection from glutathione depletion by a glyconutritional mixture of saccharides

A complex glyconutritional (GN) mixture of mono-, di-and polysaccharides was investigated to assess its capacity to protect two different types of rodent cells, rat hepatocytes and mouse splenocytes, from depletion of glutathione by a sulfhydryl-reactive mycotoxin, patulin, or by coxsackievirus B3 (CVB3) infection, respectively. Rat hepatocytes were treated with the GN mixture in vitro or received carrier medium only prior to treatment with patulin. When treated with the GN mixture prior to patulin exposure hepatocytes demonstrated protection against depletion of intracellular reduced glutathione (GSH). Cells treated with the GN for up to 15 hours prior to patulin exposure showed no increase in protection of GSH above that demonstrated by cells treated for 3 hours. Mice were infected with CVB3 and one treatment group was injected intraperitoneally with the GN once a week. Animals were splenectomized each month over a ten month treatment for analysis of spleen monocytic cells. Splenocytes from mice treated with the GN mixture did not show the virally-associated depletion of intracellular GSH or damage to pancreatic acini observed in CVB3 inoculated but non-GN-treated mice. Animals from which spleen cells were taken for analysis showed no decrease in anti-CVB3 antibodies and no decrease in viral titers to accompany or explain the normal levels of intracellular GSH. These data strongly suggest that a complex mixture of exogenous saccharides exerts a protective effect on liver cells in vitro in that the cells are protected from chemically initiated depletion of intracellular GSH, and on spleen cells in vivo in that the cells are protected against a CVB3-initiated decrease in intracellular GSH and increase in pancreatic acini damage.