Ask a Scientist – Dr. Cedric Garland and Dr. Robert Heaney
Questions and Answers with Cedric Garland, Dr. PH FACE (University of California at San Diego department of Preventive Medicine) and Robert Heaney, MD (Creighton University, Professor of Medicine and Research Director, GrassrootsHealth)
Response to newsletter, August 19, 2015
Our highlighted article this week is from Dr. Robert Heaney about the role vitamin D has played in evolution. Also featured is a fun, new children's book all about vitamin D!
I may have very early stage of MS (pending MRI). What scholarly literature exists that discusses Vitamin D and MS treatment?
Dr. Garland: I like this as a little bit of a review and a study:
When will IOM publish a retraction of their mathematically incorrect recommendations for vitamin D intake?
Dr. Garland: They have made no commitment to do this. I think it will take 3 years or so to convince them that their committee erred.
Dr. Heaney: No one knows. My bet is never.
I talk to a lot of women of child-bearing age about the benefits of Vitamin D on fertility and pregnancy. Several have said they have a medical condition that prevents them from properly absorbing Vit D. Is this a common problem?
Dr. Garland: Everyone has their own rate of vitamin D absorption. That’s one reason why it is important to set your intake of vitamin D3 based on a blood test of 25-hydroxyvtain D, the main circulating metabolite. Without this test there is no way to know whether you are a good or poor absorber of vitamin D.
Dr. Heaney: No, it’s not a common problem. There may be some confusion of terms here. “Absorption” means transfer from the intestinal contents into the bloodstream. That transfer is slow with malabsorption syndromes, such as Crohn’s disease and sprue. Thankfully, those are relatively uncommon problems. If the questioner means “utilize” rather than “absorb”, I’d have to say that such conditions are very rare indeed.
Can I buy vitamin D3 cream without an Rx? What brand is the highest quality & most absorbable? What D3 cream is best for psoriasis?
Dr. Garland: Creams that contain vitamin D3 are available. Most contain 1,000 IU of vitamin D3 per squeeze of the pump. If you are hoping for a benefit in prevention of disease, you should test your serum 25-hydroxyvitamin D to confirm that the cream is being absorbed. The rise in 25(OH)D may take a few weeks to see in the serum 25(OH)D. Be sure to buy a brand that is sold across state lines. Such brands have a least a little regulation by the Federal Trade Commission or a Canadian equivalent.
Dr. Heaney: I do not know of vitamin D creams. There was once (and may still be) an ointment containing a modified 1,25 D compound prescribed for patients with psoriasis. It is (or was) a prescription item. But I wouldn’t take it if the desire is to improve vitamin D status. You need vitamin D for that, not one of its derivatives. There are some recent reports of virtual curing of psoriasis with high daily doses (10,000–20,000 IU/d). If it were I, I’d try the high dose therapy first, before using the ointment.
Should Vitamin D3 be taken by persons undergoing chemotherapy for breast cancer?
Dr. Garland: There is no known reason to avoid vitamin D3 while undergoing chemotherapy. On biochemical grounds, it is pro-apoptotic and may enhance the ability of chemotherapy to induce apoptosis (destruction) of cancer cells. Unfortunately, we do not yet have a randomized trial of this, so you would be taking a little bit of a leap of faith.
Dr. Heaney: YES, YES, YES! As in others, keep the serum 25(OH)D above 40–60 ng/mL. The right dose is the one that achieves those blood levels
My doctor told me to stop taking vitamin D as I have been diagnosed with primary hyperparathyroidism. I will start again after I have surgery to remove the affected gland(s). Do you have any published papers on the subject?
Dr. Garland: I do not know of any specific reason to stop vitamin D while awaiting surgery on the parathyroid glands. There is probably no harm in stopping as long as the surgery is performed promptly, such as within a month or so. I would recommend that anyone with hyperparathyroidism start by reading a classic article on vitamin D and parathyroidism by Petersen et al. that gives some basics and useful, albeit classic, references. Consult the internet once you learn the language and basics from this and other papers of a good endocrinology text available in any medical library.
Petersen M et al. Parathyroid hormone and 25-hydroxyvitamin D concentrations in sick and normal elderly people. Br Med J (Clin Res Ed). 1983 Aug 20; 287(6391): 521–523.
Dr. Heaney: I know of no reason to wait. Your body needs the D now. There need be no fear that administered vitamin D will lead to excess calcium absorption, thereby worsening the hypercalcemia of hyperparathyroidism. Experience has shown that doesn’t happen.