Another autism theory to chew on

In the website of the Vitamin D Council, Dr. John Jacob Cannell, Executive Director of the Vitamin D Council, Vitamin D Theory of autism connects the theory of Vitamin D with that of toxic heavy metals (mercury, zinc etc.) as a combined cause for autism:

Does vitamin D explain the role of vaccines, mercury, and heavy metals? Vitamin D's role in increasing glutathione levels may explain the link between mercury and other heavy metals, oxidative stress, and autism. For example, activated vitamin D lessens heavy metal induced oxidative injuries in rat brain. The primary route for brain toxicity of most heavy metals is through depletion of glutathione. Besides its function as a master antioxidant, glutathione acts as a chelating (binding) agent to remove heavy metals, like mercury. Autistic individuals have difficulty excreting heavy metals, like mercury. If brain levels of activated vitamin D are too low to employ glutathione properly, and thus unable to remove heavy metals, they may be damaged by heavy metal loads normal children easily excrete. That is, the mercury in Thimerosal vaccines may have injured vitamin D deficient children while normal children would have easily bound the mercury and excreted it. These studies offer further hope that sun-exposure or vitamin D supplements may help autistic children by increasing glutathione and removing heavy metals. Not only do we have more clues that vitamin D is involved in autism, the vitamin D theory just did something else: it explained two other theories of autism, the mercury accumulation theory and the oxidative stress theory. (Lin AM, Chen KB, Chao PL Antioxidative effect of vitamin D3 on zinc-induced oxidative stress in CNS.Ann N Y Acad Sci. 2005 Aug;1053:319–29. Valko M, Morris H, Cronin MT Metals, toxicity and oxidative stress.Curr Med Chem. 2005;12(10):1161–208. Kern JK, Jones AM Evidence of toxicity, oxidative stress, and neuronal insult in autism.J Toxicol Environ Health B Crit Rev. 2006 Nov–Dec;9(6):485–99).

It bears repeating that the amount of activated vitamin D in the brain directly depends on the amount of vitamin D made in the skin or ingested orally.