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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Dear Dr Cannell: Vitamin K2 for my child?

Dear Dr. Cannell:

I have a 3 and a half year old son with autism. He has severe delays in both gross and fine motor skills, has audio sensitivities, and is primarily non-verbal. For example, he did not crawl until one, did not walk independently until two, still has an unsteady gait, cannot use utensils, he does not use words unless prompted, his pronunciation is extremely poor, he cannot put two syllables together, and generally cannot put two words together. He has extensive physical, occupation, and speech therapy since age one with little progress.

He has never had any “bio-medical intervention,” and has never had any vitamin A. We have had problems with his sleep and especially with nighttime awakening since the beginning. For the last six weeks, we have tried to consistently get him in the sun with his shirt off in an effort to obtain vitamin D and therefore improve sleep (I suspected his sleep problems were the source of his delays and knew vitamin D could improve sleep).

About two weeks ago, we began giving him 1000 IU of D3 daily, with no improvement. Last weekend we ran across several articles on your website, suggesting higher doses of D and higher blood serum levels of D led to improvements in autistic kids. Therefore, my wife and I increased his vitamin D dose to 4000 IU/day on Monday night. The next day he was more verbal, seemed more stable and was faster in his walking/running, I took him to the grocery store and he looked at a picture of an alligator then looked at me and said “aaaall, aaaall.” I had never seen him do anything like this before.

Then we had some family over for dinner and he was the most at ease socially and from the standpoint of noise sensitivity that we have ever seen him. We have continued to give him his high D dose every day and things seem to be continuing to go well especially in the area of sleep (zero nighttime awakening this week). We are testing his 25(OH)D levels today and plan on taking him the high limit of the normal range, which is 100 ng/ml.

My question concerns adding vitamin K2 to his Vitamin D treatment. Is there a possibility that adding K2 could decrease the effectiveness of the vitamin D?

Robert, New York

Dear Robert:

The vitamin K2 will not hurt him and may help his central nervous system function better. See the following review of vitamin K and the central nervous system, though I’m not familiar with any research on vitamin K specific to autism:

Ferland G. Vitamin K and the nervous system: an overview of its actions. Adv Nutr. 2012 Mar 1;3(2):204-12.

In fact, I have seen better results when K2 is given with vitamin D, though there is limited evidence why this would be the case. I suggest you switch him to D3 Plus. Cut open two capsules with a scissor and give him two capsules per day mixed in something like ketchup, fruit preserves or applesauce or put the contents of two capsules in the blender with apple juice. Get another 25 (OH)D blood test in 3 months and adjust his dose accordingly. Shoot for 80-90 ng/ml.

I think that it’s his young age as to why you are reporting that he is responding so well. In my opinion, the younger the child, the better the results one will see with D3. Some have concluded that autism is an autoimmune disorder in which the child’s immune system makes antibodies against their own brain. The longer the time this autoimmune disorder has existed, the more brain damage and the harder it is for vitamin D to help reverse the damage. However, I have seen it help adults with autism, so it is worth trying no matter the age.

John Cannell, MD

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

2 Responses to Dear Dr Cannell: Vitamin K2 for my child?

  1. bjrelyea says:

    Regarding Robert’s son with autism: I have discovered a new book that suggests that Vitamin B-12 deficiency may cause neurological problems, and ordering a vitamin B-12 blood level as well as a urinary level of methylmalonic acid can be helpful in some of these cases.
    Here is a link to a press release for the new book:


    Here is an extract of the press release:
    The underground classic that sparked a patients’ rebellion and saved lives, Could It Be B12?, is revised, updated and expanded in a second edition.
    “The definitive book on B12 deficiency, diagnosis and treatment.” —Jeffrey Dach, M.D.
    “I can honestly say this book saved my life. “ —Reader Review, Amazon.com
    Vitamin B12 deficiency is a public health crisis that even most doctors don’t know exists. Millions suffer from it, but few are diagnosed. Left untreated, it causes permanent, crippling nerve damage—and too many patients don’t get treatment until it’s too late.
    Only one book has ever revealed the full extent of this silent epidemic and taken a principled stand against the medical establishment’s indifference. That book became an underground classic that ordinary patients passed to one another and discussed among themselves, and grew into a movement that every year draws more and more patients to take control of their own diagnoses and find the truth. And now, in a second edition that is revised, updated and expanded with the latest scientific findings, Could It Be B12? An Epidemic of Misdiagnoses (Quill Driver Books, February 2011) by Sally M. Pacholok, R.N., B.S.N., and Jeffrey J. Stuart, D.O., remains the most authoritative guide to vitamin B12 deficiency.
    Six years after its original publication, Could It Be B12? continues to generate heated debate. Doctors are often uncomfortable about its claims—but no physician who has read the book can deny its evidence. And no book is more cited by ordinary people who have personally suffered from this disorder. On the Internet, in doctors’ waiting rooms, in private conversation, wherever people talk about mysterious ailments their doctors can’t seem to effectively treat—pain and tingling in the limbs, unexplained fatigue, dementia or mental illness— people ask, “Have you read Could It Be B12?”

  2. jolliejane@gmail.com says:

    I am so glad that Robert has brought up K2. According to Dr. Mercola, high doses of Vit D without K2 may lead to calcium deposits in the arteries and therefore, increase risk for CAD. I had emailed Dr. Cannell on this matter about a year ago. I had ordered D3 Plus but my son would not swallow the capsules. I will try opening the capsules and mixing them w/ apple sauce. Thanks Robert and Dr. Cannell for this post.