Dr. Kurt Kennel on Vitamin D

This Mayo Clinic Medial Edge Weekend episode features Mayo Clinic endocrinologist,  Dr. Kurt Kennel.

Medical Edge Weekend 8-27-11


  1. Posted August 21, 2011 at 4:02 pm | Permalink

    Question – I had an extremely low Vitamin D level on a blood test over 5 years ago. Dr felt it had to be a lab error, and didn’t re-test. This year, I started feeling terrible aches in my bones, went to new doc for blood work. Extremely low vitamin D levels, again, and am now on supplements and bones are beginning to feel better. Have I done permanent damage to my bones, or put myself at risk for other diseases as a result of not treating for over 5 years? Thank you so much.

    Dr. Kennel answers, “The good news is that the bone can heal. With vitamin D helping to provide adequate calcium and phosphorus for your bones to have enough mineral packed into them, they should be able to improve. Here is a scenario where one can expect to feel better especially if other tests showed the bones were suffering from the vitamin D deficiency. Osteomalacia is the medical term used to describe bones lacking calcium from years of vitamin D deficiency. Might ask your doctor if they felt this is the case.”

  2. Rami Alsaleh
    Posted August 22, 2011 at 7:03 pm | Permalink

    A doctor in Paris had recommended I take a 100,000 UI shot first thing in the morning once a month during winter months and once every 3 months during summer. I was told by another doctor that this is an absolute NO. Could you please shed some light on this? Rami

    Dr. Kennel responds, “There is a basis for taking larger doses of vitamin D infrequently. Convenience is the best reason. Vitamin D is stored in the fat so a large dose “fills up” the fat and then can slowly come into the blood over weeks to months. A recent study of 100,000 IU injection once every three months vs no injection showed more falls and fractures. Not expected! This may be one reason the second doctor spoke against this. Still, the idea that you could take a larger amount like 5,000 units once per week instead of 800 units per day is generally supported if that is more convenient for you.”

  3. B. O. B
    Posted August 26, 2011 at 9:13 am | Permalink

    I live in Westchester County, NY and start experiencing symptoms of Graves/Hyperthyroid every Fall. I become very ill through the winter months, and as slowly as the snow melts, my symptoms begin to disappear; by time Spring is fully in bloom, I feel reborn. My Vitamin D levels are inconsistent .. low at times (but not “significantly low”) and on the lower end of normal other times; Calcium seems normal. That said, I notice a significant difference in my overall well being if I am unable to soak up the rays. Unfortunately, every doctor I’ve seen does not recognize the correlation between anything in diet/environment and my condition, which has made this journey all up hill. I put myself on an elimination (all organic) diet (Gluten/Wheat/Corn/HFCS/GMO/Preservatives/Soy) and have noticed vast improvement, but reality is … Fall is approaching and I’ve begun to feel those symptoms again. PLEASE HELP ME!!!!!

    Dr. Kennel answers “It is important to note that other substances in the body and brain are affected by seasonality and sun exposure. For example, light box therapy for seasonal affective disorder does not affect vitamin D levels but can improve sense of well-bring in the winter. The association between seasonal sense of well-bring and vitamin D has been inconsistent and studies have not proven that taking vitamin D in winter prevents these symptoms. Reasonable advice for those concerned about vitamin D in winter is to take a supplement since blood levels will tend to fall throughout winter. Hope you feel better.”

  4. Carrie H.
    Posted August 26, 2011 at 2:32 pm | Permalink

    Are people with autoimmune disorders, specifically psoriasis, more prone to Vitamin D deficiency? Does your ability to develop a tan have any effect on your ability to synthesize what you receive from the sun?

  5. Dr Samit Bali
    Posted August 27, 2011 at 9:04 am | Permalink

    Post total thyroidectomy, what are the medicines to keep the Calcium anf vitamin D in normal level.

    Dr. Kennel answers, “In some people who have had their thyroid surgically removed, their parathyroid glands are inadvertently removed or damaged. The parathyroid glands control calcium levels in the blood. To maintain near normal calcium levels, they require much higher than usually recommended amounts of vitamin D and calcium each day. They might also required special forms of vitamin D (calcitriol) which the kidneys cannot make without parathyroid hormone. Determining these amounts is difficult and very different for each person in this situation. General recommendations would not apply.”

  6. Carrie H.
    Posted August 27, 2011 at 9:21 am | Permalink

    Question- does psoriasis and/or inability to develop a good tan have any correlation with vitamin D synthesis from sun exposure? I had low vit D (18) and have psoriasis and do not tan well. I was curious if these could be related. Thank you.

    (Note from Tracy-he answers both your posted questions with this answer Carrie.)

    Dr. Kennel says, “Not to my knowledge. If anything, usually think that those with fair skin who do not tend to tan well often are those who tend to burn easily. This would usually be associated with better than average vitamin D levels. I am not aware of effects of psoriasis on impairing the ability of the skin to make vitamin D with sun exposure unless the psoriasis was quite severe and involving much of the skin that could be exposed to sunlight.”

  7. Diane Manfredi
    Posted August 27, 2011 at 9:50 am | Permalink

    I am a 49 yo female who was diagnosed with low Vitamin D levels 2 years ago. I currently must take 10,000IU/day to maintain a blood VitD level of 46ng/ml. My immune system has improved and I have not had a respiratory infection since I started supplementing with Vit D. The dosage recommended by the goverment is still to low in my opinion.

    Dr. Kennel answers, “In the case of the innate immune system, immune function that you are born with, vitamin D appears to enhance the effectiveness of cells that kill invading organisms like tuberculosis. It has also been observed that individuals with higher vitamin D levels report fewer upper respiratory tract infections. It has been difficult to prove with studies of giving vitamin D or a fake pill that respiratory infections are diminished. More studies are being done.

    Your observation raises a larger, perhaps more important question. As a hormone, it may be that different people require different blood levels for for optimal health. Other hormones such as thyroid hormone, estrogen, testosterone, cortisone, etc. have a range of normal that vary by age, gender and sometimes ethnicity, It is possible that some people are best served by vitamin D levels in the 40s whereas other might be fine in the 20s? I believe so.

    This is one reason that experts disagree about how much vitamin D to take. The Institute of Medicine concluded that levels of 20 ng/mL or greater are sufficient to prevent bone disease. They concluded that too few studies supported higher levels for bone health or support higher intakes to prevent non-bone diseases. However, they did not say such other benefits did not exist or that higher levels might be beneficial but that not enough studies make the case for higher levels for the entire North American population.

    Other groups, like The Endocrine Society, agree more studies are needed but that the current evidence is good enough to support 30 ng/mL as the goal for everyone and, therefore, pretty much everyone should be taking a supplement. It comes down to what amount of proof is required. Many larger and longer studies are now being done so hopefully this will be clearer in the future.”

  8. Mary
    Posted August 27, 2011 at 9:50 am | Permalink

    Why I can’t listen live radio in my iPhone ? Can you make this option available to iPhone users?
    Thank you,

    • Tracy
      Posted August 30, 2011 at 9:07 am | Permalink

      Thank you for your message. This is something we are working to develop and hope to offer very soon.
      Thank you for listening to Medical Edge Weekend!
      Tracy McCray

  9. K.L.B.
    Posted August 27, 2011 at 10:06 am | Permalink

    Aside from Rickets, please discuss the role of Vitamin D in disease prevention – specifically cardiac disease, etc. Also, please discuss the symptomology of deficiency.

    Dr. Kennel answers, “In many parts of the body, think of vitamin D as a facilitator of normal function. This is typical of many hormones. They support each body part to function most efficiently. Most tissues in the body can use vitamin D in ways that are unique to those tissues. The effects of vitamin D deficiency on these tissues may take many years to manifest.

    This is why so many diseases could potentially be impacted by vitamin D. However, it is also why the list of symptoms that could be caused by vitamin D deficiency is long non-specific. By non-specific we mean that those symptoms could equally likely be caused by problems other than vitamin D deficiency. Take fatigue, persistent pain or low mood as examples. If you have one or more of these concerns and your vitamin D level is checked and is low, you may be disappointed to find that your symptoms do not improve with vitamin D supplementation. Others have their vitamin D level discovered to be quite low and they feel entirely fine including no better once they start taking a vitamin D supplement.

    As such, I caution people from focussing too much on vitamin D or ignoring other people causes and treatment of their symptoms while encouraging good vitamin D nutrition for overall health.

    In the case of the heart, a pivotal study being done on vitamin D and the heart is called the VITAL study (http://www.vitalstudy.org/index.html). The study is still looking for volunteers.”

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