Early vitamin research identified vitamin D as the way to treat rickets, or malformed bones. More recent research confirms that vitamin D is indeed essential for strong healthy bones. But its effects go far beyond bone. Inadequate vitamin D has been linked to a higher risk for many different cancers, cardiovascular complications, arthritic joints, type 2 diabetes and muscle weakness.
Although referred to as vitamin D, it is not so much a vitamin as the precursor to a hormone. How does it work? Why are do so many Americans have low levels of vitamin D, and how should they be getting more?
Guest: Bruce W. Hollis, PhD, is Professor of Pediatrics and Biochemistry and Molecular Biology Director of Pediatric Nutritional Sciences at the Medical University of South Carolina in Charleston, SC

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  1. Amy
    Huntersville, NC

    Thank you for this information. I have just begun a vitamin plan, since I am nearly 50 have felt the need to begin since I just had a metatarsal stress fracture w/o anything specific occurring.
    I am taking:
    Salmon Oil 1000 mg, 1800 Calcium +1000 iu Vit D 3, 5000 Vit D, Multi Mineral, and Garcinia Cambogia.
    Was wondering if I should also be taking Vitamin K and perhaps more B’s?
    It is rather overwhelming to navigate the Vit/Mineral world.

  2. Doerte


    I am 72 years old and am wondering, what dosage of B 12, D3 and
    Omega 3 are advised and if they should be taken daily?

    Thank you for your response

  3. Stumbo

    @ Dolly O
    In the past I would get serious nausia along with aches and pains after eating raw carrots or taking many different types of vitamins/supplements in pill/capsule/gel tab form. I noticed the raw carrot problem about 15 years ago when I was 43. I think the problem with the tabs has gone on for about 10 years or so. One time I went to the Dr. and complained about serious overall body ache and the feeling that somehow I was getting poisoned. The Dr. didn’t have any answers.
    That was bad, real bad times. If I was taking something that was “poisoning” me, I desperately needed to figure it out. I increased my water intake, changed to very bland/limited calorie diet and I also stopped taking all my supplements. Sure enough, within a few days I felt fine. It was one of the supplement’s coatings that was causing the problem.
    However, some tabs didn’t bother me so I started investigating the composition of the binder to see if I could figure out specific ingredients that bothered me. Enteric coating didn’t bother me so I chalked up my nausea to some kind of allergy or like some foods, just something that didn’t sit right with my digestive system. While that turned out to be true the reason was more complicated but how I was able to solve my problem was very simple.
    After reading many, many articles/books/websites and listening to various medical shows, I noticed none of my doctors were checking my vitamin levels. After finally getting one Dr. to test my B12 and D3 I was able to get some information that would change my life.
    My B12 level was 545 and D3 level was 23. The Dr. stated that my B12 level was fine and I needed to increase my D3. I tried to take D3 tabs but the nausea came back and I had to stop.
    While my b12 was in the middle of the range, I decided to use liquid supplements (15,000% of daily value) to see if I could tolerate them and to see if I felt better with a higher level of b12 in my blood. Sure enough, within 6-9 months I was more energized, had better thinking skills and my short and long term memory improved substantially. Best of all, some low grade fatigue I had been suffering from for years was lifted a quite bit, especially felt upon waking up. My B12 level increased to 1045 so I cut back to every other day.
    What was surprising was after increasing my B12 levels, the nausea from carrots and tabs went away. I did take liquid D3 for about 2 years and now am using tablet form without a problem. I also take several other supplements in tab form without problems. Liquid Omega 3 fish oil has been a big plus for helping my mental faculties.
    With D3, my levels went from 23 to 67 in about 8 months and I felt very good. Those months were from April to November (southern California area). I did spend a quite a bit of time outside during the summer.
    Unfortunately, from November to February, my level went back to 24, all the while I was taking 4k units a day. I have parathyroid/calcium problems now so that’s being investigated.
    Another big change in my life was the reduction of time being ill. I used to get seriously ill about twice a year, whether it be flu (I always got my flu vaccine), virus or some other infection (usually sinus). Always on meds,always in bed for 2-3 weeks and was known within the family as always missing family events. Within the last 2 years I had a very mild 1 day sniffles last year and this year a few days of a sinus problems that did not progress to serious as they usually did.
    One book that helped me quite a bit is Dr. Jacob Teitelbaum’s “Fatigued to Fantastic!”.
    Hope some of this helps.
    Good luck.

  4. Lillian

    The website of Michael F. Holick, Ph.D., M.D., author of _The Vitamin D Solution_: http://www.vitamindhealth.org
    I don’t find anything in his book to answer your question, but perhaps he has a blog on his website.

    • Emma

      Does all these amounts and supplements also apply to one who is 95 yrs. old?

  5. Dolly

    Hi, I listened to your talk about vitamin D and I have a question,
    I have tried taking different kinds of D and they all make my bones very sore. I had a friend who told me I wouldn’t have a problem with D3 but the soreness was the same. I always have an reaction to the pills within 3 days of starting to take them. I also have the same problem with all kinds of calcium.
    I just wander how many other people who think they have
    arthritis would be ok if they just stopped taking the vitamin D.
    I was only taking 200 mg morning and night. I also can’t eat oranges
    or other citrus fruits or tomatoes without paying for it with
    my bones becoming very sore. I’m 63 years old and have had this problem
    for over 20 years.
    Thank you
    Dolly O

  6. Shirley

    I have Interstitial Cystitis (painful bladder syndrome) and can tolerate taking only 400 IU’s of Vitamin D3 daily. Taking more than that causes a lot of bladder pain. My blood level is low – only 23 – even though I also sit in the sun at least 20 minutes a week and eat salmon 3 times a week. Dairy products also hurt IC, so I avoid them. I have no idea why Vit D3 causes such bladder pain for some of us with IC. What can I do to get the necessary Vitamin D3?
    Thanks for any help anyone can give me.

  7. Nancy

    I take a muli vit that has 2000 mg of vit-D-3 and a calcium with 500mg vit D-3. I’m a 64 yr young female. Should I take more? Nancy

  8. samuel

    What about vitamin D daily intake with 1% milk or soy milk?
    Is there any thing that offsets the strengths of vitamin D? I heard it does a lot more than just build strong bones. It gives you energy?

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