Vitamin D Increases Sociability in Autism Prone Offspring

Although a complete understanding of autism spectrum disorder (ASD) still remains elusive, two possible causes or influential factors for the disorder’s pathophysiology have been put forth. Viral infection during pregnancy and vitamin D deficiency have each been established as capable of increasing the likelihood of an ASD diagnosis. Animal models have revealed that this may be due to maternal immune activation (MIA) which involves oxidative stress and multiple cytokine-related inflammatory events.

Vitamin D deficiency has already been linked with autism-related dysfunctions during language and cognitive development in children[8]. Similar behavioral profiles have been noted in offspring that had a prenatal viral infection. Both vitamin D deficiency and viral infections lead to inflammation and scientists are currently exploring the possibility of the convergence of these inflammatory pathways as responsible for causing psychiatric and brain abnormalities.

A group of researchers wanted to see the effects that vitamin D would have on autism-related phenotypes. So they used the MIA mouse model and created several experimental conditions in order to test their theory that vitamin D administration would be able to prevent some of the behavioral dysfunctions associated with ASD.

To induce MIA, the researchers used the most commonly used MIA animal model: gestational exposure to a certain viral synthetic analog, polyriboinosinic-polyribocytidylic acid (Poly(I:C)). This viral mimic is a double-stranded RNA which induces, in both the mother and the fetus, a cytokine-related viral-like acute-phase. This model was initially developed and introduced as a schizophrenia model but has since been reproduced for uses relating to ASD[9].

The researchers used several experimental groups to test out their hypothesis that vitamin D supplementation would ameliorate the behavioral and cognitive problems brought about by viral Poly(I:C)-induced ASD.

To create the experimental conditions, researchers subcutaneously injected pregnant dams with either a vehicle solution (to serve as the control group) or with 1α,25 dihydroxy vitamin D3, a hormonally active form of vitamin D (Vit D ). Then, the same rats were intravenously injected with either a saline solution or poly(I:C). So, there were four groups in total:

Poly(I:C) + Vit D

Poly(I:C) + Vehicle (VEH)

Saline solution (CON) + VEH

CON + Vit D

For this particular experiment and model, the Elevated Plus Maze test showed that there were no group differences when it came to behaviors that connote anxiety. All the groups showed similar performance in the open arm distance traveled, in the percent of time spent in the open arms, and the total distance traveled. So, all the groups had about the same levels of anxiety throughout the experiment.

What was remarkable, however, was the behavior exhibited during the Y-Maze by the poly(I:C) mice which would be destined for ASD-like behaviors due to their prenatal exposure to the vital synthetic analog. The baby mice that were exposed to the poly(I:C) and given the Vit D supplement showed a reduction in ASD symptoms when it came to social interactions as demonstrated by the subsequent increase in relative time spent with a new, unfamiliar mouse. Unsurprisingly, the young poly(I:C) mice which were given a vehicle solution instead retained the ASD-like behaviors and showed social avoidance. The stark differences between the two poly(I:C) groups (one given a Vit D supplement and the other not) suggests that Vit D supplements have the ability to block the negative effects associated with MIA-related ASD on social cognition and behavior[10].

The introduction of vitamin D to the MIA autism-phenotype disease model demonstrated noteworthy results which should be further explored by other researchers interested in psychiatric diseases, mental health, behavior, and well-being.

Vitamin D Intake Improves Memory in Diabetic Mice

Diabetic mice have also been documented to show behavioral responses to vitamin D. To study the interplay between vitamin D and learning and memory impairment in diabetic mice, a group of scientists made use of the streptozotocin-induced diabetes animal model.

To measure the animals’ learning and memory abilities, the researchers used an Active/Passive Avoidance Shuttle Box which is the apparatus needed to run a passive avoidance test. In the passive avoidance test, the animals are expected either to avoid performing a particular behavior (the “passive” component) or to perform a particular behavior (the “active” component), in order to stay clear of the aversive, experimental stimuli.

The trials began with placing the mouse in the light area of the shuttle box and each time the mouse went into the dark area, it would receive a foot shock! So, the mice had to learn to override their innate preference for the dark (mice and rats prefer dark areas over light ones).

In general, the diabetic mice supplemented with vitamin D exhibited different learning patterns and behaviors from the control diabetic mice which were not given treatment. The vitamin D supplemented diabetic mice had a shorter initial latency than the non-treated diabetic group, meaning that they had better learning abilities. In fact, the supplemented mice performed at the level of the healthy non-diabetic control group. Furthermore, when the diabetic mice were given vitamin D, they ended up spending the least amount of time in the dark compartment out of all of the groups! The fact that the vitamin-D treated diabetic group had the least number of entries in the dark room shows that they were most able to retain the trained behaviors they had learned[11].

In humans, diabetes is associated with memory deficits, but also an array of other conditions, such as depression. In a randomized double-blind study, overweight and obese people that were given a high dose of vitamin D supplements had ameliorated or decreased symptoms of depression after year-long supplementation as revealed by changing scores in the Beck’s Depression Inventory[12].

Therefore, vitamin D is able to affect many domains of behavior and cognition, including learning, memory, and mood.