Low levels of vitamin D in elementary school could spell trouble in adolescence

August 20, 2019

Science Daily/University of Michigan

Vitamin D deficiency in middle childhood could result in aggressive behavior as well as anxious and depressive moods during adolescence, according to a new University of Michigan study of school children in Bogotá, Colombia.

Children with blood vitamin D levels suggestive of deficiency were almost twice as likely to develop externalizing behavior problems -- aggressive and rule breaking behaviors -- as reported by their parents, compared with children who had higher levels of the vitamin.

Also, low levels of the protein that transports vitamin D in blood were related to more self-reported aggressive behavior and anxious/depressed symptoms. The associations were independent of child, parental and household characteristics.

"Children who have vitamin D deficiency during their elementary school years appear to have higher scores on tests that measure behavior problems when they reach adolescence," said Eduardo Villamor, professor of epidemiology at the U-M School of Public Health and senior author of the study appearing in the Journal of Nutrition.

Villamor said vitamin D deficiency has been associated with other mental health problems in adulthood, including depression and schizophrenia, and some studies have focused on the effect of vitamin D status during pregnancy and childhood. However, few studies have extended into adolescence, the stage when behavior problems may first appear and become serious conditions.

In 2006, Villamor's team recruited 3,202 children aged 5-12 years into a cohort study in Bogotá, Colombia, through a random selection from primary public schools. The investigators obtained information on the children's daily habits, maternal education level, weight and height, as well as the household's food insecurity and socioeconomic status. Researchers also took blood samples.

After about six years, when the children were 11-18 years old, the investigators conducted in-person follow-up interviews in a random group of one-third of the participants, assessing the children's behavior through questionnaires that were administered to the children themselves and their parents. The vitamin D analyses included 273 of those participants.

While the authors acknowledge the study's limitations, including a lack of baseline behavior measures, their results indicate the need for additional studies involving neurobehavioral outcomes in other populations where vitamin D deficiency may be a public health problem.

https://www.sciencedaily.com/releases/2019/08/190820130917.htm

Vitamin D study sheds light on immune system effects

April 17, 2019

Science Daily/University of Edinburgh

Scientists have uncovered fresh insights into how vitamin D affects the immune system and might influence susceptibility to diseases such as multiple sclerosis.

Vitamin D is produced by the body in response to sunlight and is often lauded for its health benefits. Researchers found it also affects key cells of the immune system.

This discovery might explain how vitamin D regulates immune reactions that have been implicated in autoimmune diseases such as MS.

The University of Edinburgh team focused on how vitamin D affects a mechanism in the body's immune system -- dendritic cells' ability to activate T cells.

In healthy people, T cells play a crucial role in helping to fight infections. In people with autoimmune diseases, however, they can start to attack the body's own tissues.

By studying cells from mice and people, the researchers found vitamin D caused dendritic cells to produce more of a molecule called CD31 on their surface and that this hindered the activation of T cells.

The team observed how CD31 prevented the two cell types from making a stable contact -- an essential part of the activation process -- and the resulting immune reaction was far reduced.

Researchers say the findings shed light on how vitamin D deficiency may regulate the immune system and influence susceptibility to autoimmune diseases.

The study, published in Frontiers in Immunology, was funded by the Medical Research Council, Biotechnology and Biological Sciences Research Council, Natural Environment Research Council and Wellcome.

Professor Richard Mellanby, of the University of Edinburgh's Centre for Inflammation Research, said: "Low vitamin D status has long being implicated as a significant risk factor for the development of several autoimmune diseases. Our study reveals one way in which vitamin D metabolites can dramatically influence the immune system."

https://www.sciencedaily.com/releases/2019/04/190417111440.htm