To keep you and your kids healthy, mentally and physically, to keep your and their brains working optimally so you all can learn, remember, get along with people, and be happy, get them outdoors a lot. This will help children with autism, but the finding is clearly broader. In Causal link found between vitamin D, serotonin synthesis and autism in new study, they write:
A new study by Rhonda Patrick, PhD and Bruce Ames, PhD of Children’s Hospital Oakland Research Institute (CHORI) demonstrates the impact that Vitamin D may have on social behavior associated with Autism Spectrum Disorder (ASD). Dr. Patrick and Dr. Ames show that serotonin, oxytocin, and vasopressin, three brain hormones that affect social behavior, are all activated by vitamin D hormone. Autism, which is characterized by abnormal social behavior, has previously been linked to low levels of serotonin in the brain and to low vitamin D levels, but no mechanism has linked the two until now.Taking Vitamin D supplements is OK in low doses, but not in higher doses: taking it alone denies you the cofactors it needs to work properly and optimally; when you are out in the sun, many other photosynthetic chemicals are made in our skin besides vitamin D. And you need vitamin K, vitamin A, magnesium and zinc, another other things, for D to work optimally and not cause health problems. Update (6-30-14, 4:30 PM): Oh, but note that, of course, some people might need vitamin D in large doses for a little while to correct some health issue, and some people might need to go to a Functional Diagnostic Nutrition doc to find the cause of some vitamin D deficiency or excess: could be some organ or chemical problem.