Getting vitamin D right

Vitamin D is, without a doubt, the most incredible "vitamin"/prohormone/neurosteroid I have ever encountered. Frankly, I don't know how we got anything accomplished in health pre-D.

Unfortunately, people I meet rarely take their vitamin D in a way that accomplishes full restoration of vitamin D blood levels. It really isn't that tough.

Here's a list of common tripping points with vitamin D:

"I take vitamin D: 1000 units a day."
This is probably the most common mistake I see: Taking a dose that is unlikely to yield a desirable blood level. (We use 60-70 ng/ml of 25-hydroxy vitamin D as our target.) Most men and women require 6000 units per day to achieve this level. There is substantial individual variation, however, with an occasional person needing much more, a rare person requiring as little as 1000 units.

"I bought some vitamin D on sale. They were white tablets."
Time and again, patients in my office who initially have had successful vitamin D replacement, despite being reminded that only oil-based forms should be taken, switch to tablets. While they initially showed a 25-hydroxy vitamin D blood level, for instance, of 67 ng/ml on 8000 units per day with an oil-based capsule, they switch to a tablet form and the next blood level is 25 ng/ml. In other words, tablets are very poorly or erratically absorbed.

I have had people use tablets successfully, however, by taking their vitamin D tablets with a teaspoon of oil, e.g., olive oil. Oil is necessary for full absorption.

"I'm going to Florida. I'll stop my vitamin D because I'm going to lay in the sun."
Wrong. 90% of adults over 40 years old have lost the majority of their ability to activate vitamin D in the skin. A typical response might be an increase in blood level from 25 to 35 ng/ml--a 10 ng increase with a dark brown tan.

There is an occasional person who, with sun exposure, increases blood levels substantially. This can occur in both fair-skinned and dark-skinned people, though I've never seen it happen in an African-American person. The occasional person who maintains the ability to convert vitamin D with sun exposure, or young people, should seasonally adjust their vitamin D dose, e.g., 6000 units winter, 3000 units summer, or some other regimen that maintains desirable blood levels. You can see that monitoring blood levels (we check levels every 6 months for the first 2 years) is crucial: You cannot know what your vitamin D needs are unless you assess 25-hydroxy vitamin D levels.

"I drink plenty of milk. I don't think I need to take vitamin D."
Oh, boy. This is so wrong on so many levels.

First of all, no adult should be drinking plenty of cow's milk. (A discussion for another day.) Second of all, cow's milk averages 70 units of vitamin D, often the D2 form (ergocalciferol), per 8 oz. Even if the FDA-mandated 100 units per day were present, an average adult dose of 6000 units would require 60 glasses of milk per day. Can you say "diarrhea"?

Likewise, other food sources of vitamin D, such as fish (300-400 units per serving) and egg yolks (20 units per yolk), are inadequate. This makes sense: Humans are not meant to obtain vitamin D from food, but from sun exposure over a large body surface area. And this is a phenomenon that is meant to occur only in the youthful, ensuring that nature takes its course and us older folks get old and make way for the young (i.e., unless we intervene by taking vitamin D supplements).

"My doctor said that my vitamin D blood level was fine. It was 32 ng/ml."

Let's face it: By necessity, your overworked primary care physician, who manages gout, hip arthritis, migraine headaches, stomach aches, prostate enlargement, H1N1, depression, etc., is an amateur at nearly everything, expert in nothing. Nobody can do it all and get it right. Likewise vitamin D. The uncertain primary care physician will simply follow the dictates of the laboratory form that specifies "30-100 ng/ml" as the "normal" or "reference range." Unfortunately, the laboratory often quotes population distributions of a lab measure, not an ideal or desirable level.

To illustrate the folly of population distributions of a measure, imagine you and I want to know what women weigh. We go to a local mall and weigh several thousand women. We tally up the results and find that women weigh 172 lbs +/- 25 lbs (the mean +/- 2 standard deviations). (That's true, by the way.) Is that desirable? Of course it isn't. Population average or population distribution does not necessarily mean ideal or desirable.

"My husband's doctor said he should take 4000 units per day. So I just take the same dose."
That would be fine if all adults required the same dose. However, individual needs can vary enormously. A dose that is grossly insufficient for one person may be excessive for another. Once again, vitamin D dose needs can be individualized by assessing 25-hydroxy vitamin levels in the blood.

"I don't need to take vitamin D. I already take fish oil."
I suspect this mistaken belief occurs either because people confuse fish oil with cod liver oil, which does contain some vitamin D. (Cod liver oil is not the best source of vitamin D, mostly because of the vitamin A content; also a discussion for another time), or because they've heard that eating fish provides vitamin D. However, fish oil capsules do not contain vitamin D unless it is added, in which case it should be prominently and explicitly stated on the label.

"I don't have to take vitamin D. It's summer."

For most people I know, if it's a bright, sunny July day, where are they likely to be? In an office, store, or home--NOT lying in the sun with a large body surface area exposed. Also, most people expose no more than 5-10% of surface area in public. I doubt you cut the grass in a bathing suit. Because of modern indoor lifestyles and fashion, the majority of adults need vitamin D supplementation year-round.

I advise everyone that gelcap vitamin D is preferable. Some, though not all, liquid drop forms have also worked. Take a dose that yields desirable blood levels. And blood levels of 25-hydroxy vitamin D are ideally checked every 6 months: in summer and in winter to provide feedback on how much sun activation of D you obtain.

If your doctor is unwilling or unable to perform vitamin D testing, fingerstick vitamin D test kits can be obtained from Track Your Plaque.

Comments (90) -

  • Peter S

    1/11/2010 2:23:47 PM |

    Dr Davis

    Many thanks for your blog! I just ordered your book, too, and look forward to getting into that.

    I have a question about lab reference values which you discuss in your post.

    I just saw my physician, and am expecting Vitamin D results at the end of this week. This is the first time I have been checked for Vit D levels. At the same time, we are also checking for ferritin levels (I just finished PPLP by the Doctors Eades).

    When we looked back at my ferritin result from last year, my doctor cautioned me against taking the levels recommended in books as a criterion for judging my lab results. His argument was: every machine is calibrated differently, and the same blood sample can give widely different readings depending on the machine used. One should therefore always judge levels in terms of the reference level developed by the lab in question, which will be adapted to their machines.

    Could you comment on this? In particular, how can I know when the reference level cited on the results print out is a true reference level, and when it is a population distribution? (I leave out of the picture for now the issue as to whether the reference level is also adequately high/low in the light of the evolutionary health perspective).

    Thanks in advance for any guidance you can offer on this:
    Peter, Brussels, Belgium

  • Anonymous

    1/11/2010 2:42:33 PM |

    I'm not sure if the Vitamin D I have is oil-based or not. It's in clear softgels, it says D-3 on the front but the supplement information lists it as just Vitamin D.

    What are some good references on supplements? Scientifically based?

  • Anonymous

    1/11/2010 3:05:28 PM |

    I know that getting to optimum Vitamin D3 levels often takes a concerted effort.  On first testing of my blood levels a couple of years ago, I was shocked to only have a level of 27!  I was taking a multivitamin, and an additional 2,000 IU's of Vitamin D daily, and I live very far south in Houston.

    Long story short, I upped my daily dosage of a quality, oil-based Vitamin D3 to 4,000 IU... then to 6,000 IU...  to 8,000 IU... to 10,000 IU... to 12,000IU... all to reach a measly 51!!!  Each of these increases was preceded by testing by a blood draw at Labcorp, authorized by my doctor.  My last increase was in August to 15,000 IU's daily, accomplished by taking 3 X 5,000 IU's of an olive oil-based Vitamin D3.

    I was tested again on 12/31 and this time the Labcorp results came in at 61.3!!! Success at last!

    I would like to get my levels closer to 70, but gee... I wonder how much more I would have to take to get there?  I have had no ill effects from the current dosage, but I don't want to make this an obsession, either.

    Obviously most people won't have to take this high a dosage, or be this relentless, to reach optimum levels... but some of us will.

    Fortunately, Vitamin D3 is relatively cheap and easy to obtain... just make sure it is oil-based and/or taken with some kind of healthy oil... and taken daily.

    Thanks for the great blog, Dr. Davis!


  • Marc

    1/11/2010 3:59:40 PM |

    Thank you as always for your great blog! I very much appreciate it.

    I use the Carlson vit d3 drops. Do you think they are ok?

    What Gelcap brand do you recommend?

    thank you and have a great week.


  • Venkat

    1/11/2010 5:18:58 PM |

    Thanks Dr.

    I tested D3 during Apr 09 and I had 30 ng/ml.

    Dec 2009 I retested again after 8 months consuming Carlson Vitamin D oil based capsules - 6000 IU every day.

    The Dec 09 test showed me I have 77ng/ml (D3). I remember reading from a user comment in Protein power blog that for every 25 lbs of body weight, one should consume 1000 IU of D3. Since I am 130 lbs, I calculated to consume 6000 IU. The calculation came to 5000 IU, I added a 1000 IU more since it is a 2000 IU tablets.

    Just wanted to share with everyone.

    Thanks, Venkat

  • Sara

    1/11/2010 5:34:43 PM |

    Wow, great post!!

  • gibby1979

    1/11/2010 6:14:22 PM |

    hey doc
    Would taking your vitamin D at the same time as taking your fish oil end up working the same as taking it with oil?

  • zach

    1/11/2010 6:36:35 PM |

    Thanks for the post. I have some questions. What's wrong with raw, full fat milk from grass fed cows? I assume you have more sophisticated reasons than "it's meant for calfs, so adults don't need it." I question this strongly because milk, butter and cream, unprocessed from pastured animals has noticeable improved my health.

    Also, where did the Inuit and other northern dwellers get their Vitamiin D in winter if not from food? Where they chronically deficient?

  • Anonymous

    1/11/2010 7:45:57 PM |

    Dr. Davis,

    Given your comments about the shortcomings of sun exposure (in the majority of cases) for adults over 40, why do you think the vitamin D Council links to 3 tanning systems on their website, namely the D-Lite, Renew, & SunSplash UV/Tanning Systems?

    While I recognize that any strategy to attempt to optimize Vitamin D levels still revolves around getting the proper test done to assess/re-assess levels, it seems like you wouldn't have enough time to use the light to assess its true efficacy in individual cases prior to the point where you'd be able to return it if it proved to be ineffective.

    I'd be curious to hear your general thoughts, that is if you feel comfortable sharing them, on why they would recommend these lights if they would potentially be of little to no use in anyone over 40.

    Thank you for your time and any input.

    Ray Mardsden

  • Dr. William Davis

    1/11/2010 8:45:33 PM |

    Hi, Peter--

    The only substantial difference are the units: ng/ml in the U.S. and nmol/L everywhere else.

    To convert nmol/L to ng/ml, divide by 2.5.

    Also, the Diasorin assay is the more accurate.

  • Dr. William Davis

    1/11/2010 8:46:39 PM |

    Hi, Madcook--

    Thanks for sharing your experience.

    Your case highlights the great individual variation in vitamin D needs, which can range several-fold.

  • Dr. William Davis

    1/11/2010 8:47:12 PM |

    Hi, Marc--

    Not enough experience with this preparation. However, a future blood level of vit D should clear this up.

  • Matt Stone

    1/11/2010 10:29:22 PM |

    Thanks Doc.  Currently trying to bring my girlfriend's vitamin D level up from 20 ng/dl.  Your post rings true in many ways as she is Norweigen (fair-skinned) and spends all summer outdoors for work with no sunscreen to little avail.  I do wonder if it's a Vitamin D receptor problem and not an issue of intake a la Marshall protocol.

  • x.ds

    1/12/2010 12:06:56 AM |

    zach said...

        Thanks for the post. I have some questions. What's wrong with raw, full fat milk from grass fed cows?

    The problem with raw milk is lactose that causes atherosclerosis and cataract and is linked to Parkinson's disease.

  • AJ

    1/12/2010 1:38:39 AM |

    Dr. Davis,

    Quick question for you regarding Vitamin D and sunlight. If one has both tanned and untanned skin (say farmers tan) will exposure of the untanned skin to the sun help synthesize more Vitamin D than the already tanned part? In other words, is the rate at which one can synthesize Vitamin D from sunlight locally controlled or centrally controlled?

    I've tried to find this answer without much success via Google, ect. Curious if you know definitively.


  • LynP

    1/12/2010 3:55:43 AM |

    Hi Doc.  16 months with increasing amts of D3 (final was/is 8K/day) finally saw my initial 15 rise to 66...hippee! Been using huge amts to battle a respiratory bug (120K/day, what do I need to know about when to stop if bug lingers, ie, is it dangerous to take such lg amts for a wk or more?  Smaller amnts are useless as I am obese (losing but still obese).  

    PS My HDL went to 60 from 47.

  • mongander

    1/12/2010 4:06:50 AM |

    My wife was diagnosed with cancer 2 years ago.  When tested for vit D level her doc commented it was the lowest level he'd ever seen.  I had her supplement 50,000iu/day for weeks and got her up to the 30s.  Sadly, the damage was too much and she died in Nov.

    I take 10,000/day in the "R" months and 5,000/day the rest of the year.  My level is 79 ng/ml.  At 70, I have prostate cancer and am in the "watch & wait" mode.

  • Michaela

    1/12/2010 4:35:55 AM |

    Thanks Dr Davis as always for your wealth of information. The timing of this post couldn't have been better as I've just this week been posting links to your blog to other parents in my position. I've been suggesting they read up on Vitamin D and it's benefits for heart disease. Like me 8 months ago, they had no idea of the necessity of this Vitamin or in fact any of the nutritional supplements you recommend. Since following your recommendations my son Lee has has gone from strength to strength and is leaving his Australian Cardiologist's scratching their heads!
    Keep up the great work Doc, you've been a Godsend to me.


  • Ajana

    1/12/2010 9:10:34 AM |

    "90% of adults over 40 years old have lost the majority of their ability to activate vitamin D in the skin."

    Please can you direct me to the literature on this. Have a friend (Asian - 49 y.o.) who thinks she does need to take Vit D as she gets a few minutes of sun (face mainly) most days.

  • Kathryn

    1/12/2010 9:26:39 AM |

    I'd be curious about your opinion of another (well-known) doc's push of krill oil.  Thanks.

  • moblogs

    1/12/2010 11:02:48 AM |

    What's very concerning is that 'from' 21nmol/L up to 128nmol/L is seen as sufficient according to guidelines in London, England. At 141nmol/L I'm a real rebel!

  • TedHutchinson

    1/12/2010 12:31:21 PM |

    Deer and Reindeer feed in winter on lichen which is good source of vitamin D.
    It is reasonable to suppose eating meat with a high vitamin D status would eek out the vitamin D stored in summer.
    Eskimos tradionally fermented, in grass-lined holes, whole fish, fish heads, walrus, sea lion and whale flippers, beaver tails, seal oil, birds, etc for an extended period of time. Several of these are likely to be good sources of Vitamin D3 that would help them survive the long winter.
    Human stores of D3 would not deplete so fast in peoples not consuming grain, fructose or pro inflammatory industrially made omega 6 vegetable/seed oils.
    It isn't just reindeer and caribou that eat vitamin D rich lichen Snails, sea slugs, lemmings, musk ox, and insects also eat them, as do Eskimo groups in the Arctic.

    It is possible birds eating lichen grazing snails also have higher vitamin D status. People eating those birds would thus benefit.

    Muktuk Inuit/Eskimo meal of frozen whale skin and blubber also contains vitamin d.

    Here is a 2004 quote from a woman talking about her childhood Discover The Inuit Paradox
    Our meat was seal and walrus, marine mammals that live in cold water and have lots of fat. We used seal oil for our cooking and as a dipping sauce for food. We had moose, caribou, and reindeer. We hunted ducks, geese, and little land birds like quail, called ptarmigan. We caught crab and lots of fish—salmon, whitefish, tomcod, pike, and char. Our fish were cooked, dried, smoked, or frozen. We ate frozen raw whitefish, sliced thin. The elders liked stinkfish, fish buried in seal bags or cans in the tundra and left to ferment. And fermented seal flipper, they liked that too.”

    This 2007 study found YUP’IK ESKIMOS who consumed the most traditional foods obtained on average 1232iu/D from food.
    That is a lot more than most UK adults get from current dietary intakes.

  • TedHutchinson

    1/12/2010 12:56:42 PM |

    This Study of Belgium older women Rural Urban shows that some older women living in the less polluted rural location were still capable of making vitamin D. It was living in a polluted urban environment that made the most difference between the groups.

    But the only way you have of knowing how well your skin responds to sunlight or UVB from tubes is to get a 25(OH)D3 test.

    If you look at the plot from that study you will see there are a lot of older women (both town and country dwellers) with very low 25(OH)D status.
    So although older skin is less able to respond to UVB it MAY make useful amounts of vitamin D if given the chance (but it also MAY NOT
    A daily effective strength oil based gel capsule WILL improve 25(OH)D3 level.

  • Henry North London

    1/12/2010 3:30:04 PM |

    My blood levels of Vitamin D3 are 83ng/ml

    I achieved that by taking 50000 iu units of Vitamin D3 through September, October and November daily, I then dropped to 20000 iu ( primarily through cost and then did a fingerstick and sent it off in Mid December) I still take 20000iu a day

    I have not had a sniffle or a chest infection or anyother infection since I took it.

    Nothing,  Zip Nada,  It has been the best winter ever, because my aches and pains have gone, my health has been good and I have positively enjoyed not getting unwell at all.

    Most people look at me as if Im completely crazy when I shovel down four gel caps a day or more but I take the view that this is what my body would make in June in high summer in a bathing suit daily

    So Im happy and I have another fingerstick in 6 months time

    My grip strength has improved and I never get colds for any length of time, they are gone in 24 hours

    I  spend most of my days indoors so Im very happy now and I have darker skin too. But I had to be really ott with the gel caps to bump it up to 83ng/ml

  • SMK

    1/12/2010 4:40:12 PM |

    Dr Davis

    Thanks will be small words to decribe your blog and the immense benefits we as regular people can avail ,due to your excellent blogging efforts.

    My husband and me just got our LabCorp 25(OH) results, each severely deficient with <10 ng/ml.We have started supplementing with 6000 IU Carlson Soft gels.
    Your article did not address one question of how long does it take to bring up the numbers to about 60-70ng/ml?We have plans to add a new mmber to our family and am concerned that we should not do this until..I am not sure.Your response is much appreciated.

  • Dr. William Davis

    1/12/2010 6:20:34 PM |


    While I know of no study directly studying this, it would make sense that untanned skin would generate the most vitamin D, since vitamin D activation is limited with tanned skin as a self-limiting phenomenon.

  • Dr. William Davis

    1/12/2010 6:24:45 PM |

    Hi, Michaela--

    I'm glad your son continues to do well.

    Please stay in touch. You bring an aspect of this conversation that we don't hear much about. It might help spread the word with your enlightening experience.

  • Dr. William Davis

    1/12/2010 6:25:59 PM |


    While I believe that krill has some interesting potential properties, I believe that its manufacturer has done us a disservice with its extragant and misleading claims. This will be the topic of a future blog post.


    Thanks for the great comments!

  • TedHutchinson

    1/12/2010 6:32:51 PM |

    @ SMK
    Circulating 25-Hydroxyvitamin D Levels in Fully Breastfed Infants on Oral Vitamin D Supplementation
    This free full text online paper details some of the work Hollis and others have done on vitamin D supplementing in pregnancy and during breastfeeding. 6400iu in total was required at latitude 32n to achieve optimum vitamin D3 in breast milk.
    This paper explains how higher vitamin D status is linked to higher testosterone levels (the full text talks about other fertility benefits) so it isn't just the mother that needs  optimum vitamin D levels.

    Grassrootshealth response chart
    there are some other graphs showing response to 5000iu/d here in the LEF SURVEY of 13000iu people
    When you study both these sources you will see it's impossible to say   for certain that 6000iu/daily WILL definitely take you over the 60ng/ml level.
    Figure 3 from the LEF article shows 5000iu only got people to average just over 40ng/ml in 3~9 months. 6000iu will do better and you may find, if you are good responders that in 2~3months a 25(OH)D test will prove you are around 60ng/ml but if you want to speed the job up, a little more D3 at this time of year (January)until April may be advantageous.

  • Rayboy

    1/12/2010 8:02:44 PM |

    There are five different forms of Vitamin D.

    Do we really know if taking a large supplement of just one of them, D3, is the absolute optimal nutritional strategy for health?  It would seem like in addition to supplements, getting some sunshine whenever possible would be a good idea, to aid our body in producing the form and amount of Vitamin D it needs.

  • Rayboy

    1/12/2010 8:32:03 PM |

    Follow-up: This site allows you to calculate how much sun exposure you need for your skin to manufacture 25 mcg of Vitamin D.  It is quite sophisticated, with fields for latitude and longitude, cloud conditions and reflective surfaces.

  • pmpctek

    1/12/2010 10:21:29 PM |

    "Cod liver oil is not the best source of vitamin D, mostly because of the vitamin A content; also a discussion for another time." - Dr. Davis

    Is this due to a risk of vitamin A toxicity and osteoporosis from too much synthetic forms of vitamin A and/or when vitamin D blood levels are below optimal as described in your article?

    I've read from many sources that vitamin A toxicity is not a concern as long as the sources of vitamin A are natural, such as from green leafy vegetables, organ meats, or CLO, and D3 blood levels are optimal.

    I take Garden of Life Icelandic Cod Liver Oil, which preserve the natural forms of vitamin A and D in their processes.  Most brands of CLO (especially the cheap ones) use a distillation process which destroy these vitamins.  These cheaper brands then add them back into the final product with synthetic forms.  Green Pasture's Blue Ice and Radiant Life are other brands that keep natural forms of vitamin A and D in their products.

    I take an additional 6,000IU/day D-3 gelcaps and I've been able to maintain my serum 25-hydroxyvitamin D3 levels at ~60ng/ml.

  • Anonymous

    1/12/2010 11:09:57 PM |


    I've tried taking 1000IU of Vitamin D Gelcaps and got short of breath and felt slightly nauseous after just one dose.  I've talked to several people about this but nobody seems to have an answer.  If you have any insight, I'd appreciate it.

  • Dr. William Davis

    1/13/2010 12:15:45 AM |

    Hi, Rayboy--

    I agree: Getting some sun is even better, if you have that option.

    I look out my window and it's supposed to be another 20 degree day. I will be covered head to toe, and I don't expect this will change for another 5 months.

  • Dr. William Davis

    1/13/2010 12:16:37 AM |


    We see these rare reactions every once in a great while. But I am uncertain why they happen. We have had some success starting at very low doses, e.g., 800 units per day, and building up very gradually.

  • SMK

    1/13/2010 4:42:59 PM |

    Ted,Many thanks for all those links about breastfeeding and VitaminD in breastmilk.I was one of those unfortunate ones who did not get any breastmilk..just colostrum.The doctors did not bother to advice anything other than saying  formula will save the child now.
    I do suspect my Vitamin D was severely low then too.We live in PA .

    I am upping my IU for D3 now to8000/10000 daily for the next three months.

    Thanks again Dr.Davis for this blog!

  • TedHutchinson

    1/13/2010 4:50:39 PM |

    @  Rayboy
    25mcg = 1000iu As we have seen from the several surveys I've linked to, around 1000iu for each 25lbs is probably required. So either you need to expose more skin than just hands/face or spend a lot longer outside.

    There are some differences of opinion about the current state of knowledge underlying that calculator's computer model.
    Is the action spectrum for the UV-induced production of previtamin D3 in human skin correct?
    That paper points out using real people, rather than computer modelling, it has been shown conversion of 7-DHC to previtaminD occurred throughout the year 34N and below, but no production of vitamin D3 was found in the winter months of Nov~Feb at 42N (Boston) or Oct~March at 52N (Edmonton)
    It's what matters in practice that's important, not what the computer says.
    I don't want you laying naked in the midday winter sun freezing to death just because the calculator is saying that free vitamin D3 is theoretically possible when in practice we know it doesn't happen.

  • kilo.oscar

    1/13/2010 5:16:45 PM |

    Dr. Davis

    You recommend gelcaps over tablets, but what are your thoughts on chewables?

    I'm female, 120lbs, 6 months post femur fracture / pinning and taking:
    chewable multivitamin (400) + chewable calcium (200) for 600 IU
    'gummy' vitamin D (1000) + 2x oscal (400) for 1400 IU

  • Kevin

    1/13/2010 6:42:40 PM |

    I was in Colorado for a medical conference and noticed a lot of ads for tanning beds.  They're advertising that tanning beds increase Vitamin D substantially in just ten minutes a day under the lights.  


  • Anonymous

    1/13/2010 7:19:39 PM |

    Robert S.

    Great write up Dr. Davis,

    When Dr.'s recommend getting patients blood levels checked, they are sent for 25(OH)D levels.  But would it be more optimal to have them checked for ONLY D3 and not the 25(OH)D?  What do you think is the best way to check d levels in blood is what I guess I'm asking, thank you. Smile

  • Dr. William Davis

    1/13/2010 7:27:27 PM |


    25-hydroxy vitamin D is the preferred test, the "repository" form prior to conversion to the 1,25-dihydroxy form.

  • Anonymous

    1/13/2010 9:47:35 PM |

    Robert S.

    Thanks for the quick reply.  Are there labs/hospitals that test  Vitamin D3 or do they only do 25(OH)D / 25(OH)2D?

  • Anonymous

    1/13/2010 11:40:36 PM |

    "We see these rare reactions every once in a great while. But I am uncertain why they happen. We have had some success starting at very low doses, e.g., 800 units per day, and building up very gradually."

    I experience milder symptoms when I drink Vit D fortified milk - but not so mild that I can continue drinking it.

  • Stephen

    1/14/2010 2:45:49 AM |

    I'm wondering the same thing another person asked - would taking D3 in tablet form with fish oil caps work?

    Thanks Doc.


  • Peter S

    1/14/2010 9:04:13 AM |

    Dear Dr Davis

    Thanks for confirming that. Apparently here in Belgium we have ng/ml readings too. Mine came in at 8!

    My physician is recommending a massive one-off dose to restore them to the 30 ng/ml that is believed to be normal here.

    Does anyone know if these large single doses (taken in oral liquid form) are more or less effective than regular supplementation in sustainably restoring levels?

    (I know you believe the ideal level should be somewhat higher at around 60, not 30)

    Thanks in advance

  • jpatti

    1/14/2010 3:43:23 PM |

    Raw milk from cows on pasture has real vitamin D in it.

    When I started getting milk from a local farmer, my bp went WAY down even though I'd run out of Lisinopril.  I'm hooked on it now after not drinking any milk for decades.

    I still take my D3 supplements though.  I don't feel you can correct long-term deficiencies with just diet.  Maybe if I'd been drinking that good stuff all my life, I'd be fine, but I wasn't.

    You can find a source of milk near you here:

  • jpatti

    1/14/2010 3:45:31 PM |

    P.S. Raw milk contains lactase which handles the lactose just fine (unless you're already lactose-intolerant from years of drinking pasteurized milk).

  • Dr. William Davis

    1/14/2010 4:56:55 PM |

    Fish oil with vitamin D is not generally a reliable means of absorbing the vitamin D, since dissolution of the gelcaps may not be simultaneous. Of course, you can determine this with a blood level. I'd rather just take the gelcap.

  • zach

    1/14/2010 7:55:25 PM |


    You are correct, at least in summer the milk has it. I have a milk cow and my level in summer was 70 ng/ml without supplementation for 5 months. Store bought milk has ineffective D2 added to it. The animals are in confinement and are fed grains so their milk is devoid of D. Store bought milk is unfit for human consumption. The animals are sick unto death and their product reflects that. And that's before the boiling and high pressure processing.

  • Electronic Medical Records

    1/15/2010 5:39:35 AM |

    This is an awesome update...I agree 200% with the update.There are these myths which engulf us half untrue...we live with them.

  • Chloe

    1/16/2010 5:20:34 AM |

    After joining Vitamin D Experiment Forum on I took the plunge (no insurance) and paid for a 25-hydroxy vitamin D test in March 2007.  Result was 7.  Some background.  My paternal grandmother, father, and I suffered from severe seasonal affective disorder, sister had rickets as a child.  

    I started taking 14,000 IU (inched up to it) daily of Carlson's 2000 IU gelcaps and after joining GrassRootsHealth and doing home testing my next level 18 months later was 99.  I backed off to 8000 IU a day and next reading six months later was 94.  I am currently taking that 8000 IU daily and 10,000 IU daily when dark outside.  Next test coming up.  I watch that list of symptoms of overdose and so far no symptoms.  

    I have become a bit of a vitamin D preacher and have given books (The Vitamin D Cure) and a bottle or two to friends at high risk, but until the receiver is ready they care not.  One is the survivor of breast cancer and now chronic lymphocyti leukemia whose mother was a very popular herbalist in Southern California for over 50 years, another the survivor of a heart attack sustained after a stent was placed (the stent clogged), and another a black family, dark skinned who really are at more risk than pale old me.  Very reluctant and all have used one of the excuses you have listed.  Go figure.  

    Thanks for the information.  I will keep passing it along and keep trying.

  • Loïc Raharison

    1/16/2010 2:45:47 PM |

    Is there any difference with the oil used in the softgel? For example the NOW brand use Rice Bran Oil and the Carlson Lab uses Safflower oil. Any insight on this?

  • TedHutchinson

    1/16/2010 4:11:43 PM |

    Most Vitamin D3 oil based capsules are quite small, so the little extra oil, calories consumed isn't a major consideration.

    Carlson Labs, Solar D Gems, 4,000 IU  360 $29.19 are in Cod liver oil but total omega 3 content is a mere  115mg Omega-3. Most people will require additional omega 3 fish oil sources, so please don't think by taking a small Vitamin D3 Capsule in fish oil you are fully covering both D3 and Omega 3 requirement.

    Those who want to avoid soy, rice bran, sunflower oil or other industrially make omega 6 oil  may prefer either
    Country Life, Vitamin D3, 5,000 IU, 200 Softgels $10.20 in MCT oil. Medium Chain Triglyceride oil is readily burnt as fuel so less likely to be added to fat cells MCT is also less likely to go rancid.

    Another option for 10,000iu/users is Healthy Origins, Vitamin D3, 10,000 IU, 360  $23.95 these are in olive oil. (Other strengths available).

  • Sherrie

    1/17/2010 12:24:12 AM |

    I just wanted to share that towards the end of Autumn I had my vitamin D tested at 59 nmol which is around 23ng. In Australia the highest dose available seems to be 1000ui so I started with that but soon bought 5000ui gelcaps from the US. Towards the end of Spring (I live down south so this was through a winter) I tested at 150nmol which is around 60ng and was told to stop. I have fair skin and hair. I don't feel any the better or worse for it.

  • Anonymous

    1/20/2010 4:44:21 AM |

    I've been taking 5000 iu's of Vitamin D daily since the end of October and for the first time since I can remember I've made it thus far into the cold/flu season without so much as a sniffle.

    Regarding brands. I take Vitamin DDrops. Flavourless/odourless, 5 drops under the tongue every night.

    Dr. Davis, are you familiar with this particular brand? Would you recommend it? I only ask because you stated in this piece that only some forms of liquid actually work.


  • drdonaldson

    1/31/2010 5:25:59 AM |

    Great information. I use a liquid D3 gelcap in a sesame oil base for maximum absorption.

  • Steven Low

    2/7/2010 11:03:20 PM |

    "Another option for 10,000iu/users is Healthy Origins, Vitamin D3, 10,000 IU, 360 $23.95 these are in olive oil. (Other strengths available)."

    That's the one I'm taking. Cheapest one out there ATM.

    After I wrote this:

    I've been on 10,000 IU for about 4 months now. Feel great.

  • Ellen

    2/19/2010 3:19:55 AM |

    Dr. Davis, have you read this paper?

    It basically says for those who suffer from autoimmune diseases, Vitamin D supplementation may worsen disease symptoms over the long term because it acts as an immunosuppressant of reactions toward bacterial ligands to the VDR.  This allows the underlying disease to worsen over the longterm.  Your thoughts?

  • TedHutchinson

    2/19/2010 6:19:25 PM |

    Dr Davis's previous blog Marshall Protocal and Other Fairy Tales
    also consider
    Mark London's refutation of the Marshall protocol.

    It's also worth going through Mercola's detailed refutation.

    The study I refer to in Mercola's comments section (and Mark London refers to) showed that using computer modelling they found that Calcidiol, the circulating form of vitamin D, (previously regarded as inert and requiring a further hydroxylation (to become Calcitriol) before it was effective,) does in fact bind with  Calcitriol to activate the Vitamin D receptor. Calidiol isn't BLOCKING the VDR but is working in synergy with calcitriol to become effective at lower concentrations.

    There is still lots of work to be done on this but the findings that Curcumin (turmeric) also activates the VDR
    Vitamin A in excess can also bind with VDR (but in this case it does block the action and isn't helpful) The action of cucumin is helpful, it's always puzzled me why so many of the benefits of curcumin are identical to those of vitamin D3 so now we know why.
    We have to look at what actually happens in practice.
    People with higher vitamin D status generally live longer lives with less chronic illness and with fewer infections.
    If the Marshall protocol were correct  the opposite would occur. We would find in practice those with lower D3 generally had the advantage.

  • Brendan

    2/24/2010 5:59:20 PM |

    Dr Davis

    Many thanks for your post.

    I have a question. Is the presence of soy oil or corn oil in the oil-based vitamin D capsules an issue worth considering?

    I am worried about their omega 6 contents

  • TedHutchinson

    2/24/2010 7:05:46 PM |

    Country Life, Vitamin D3, 5,000 IU, 200 Softgels $10.20
    these are in MCT oil
    Healthy Origins, Vitamin D3, 5,000 IU, 360 Softgels $14.95
    and these are in olive oil
    Carlson Labs, Solar D Gems, 4,000 IU, 360 Soft Gels $29.19 (note the D3 content is lower and price higher)
    these are in fish oil so provide a small (trivial) contribution to your omega 3 intake. You will still have to supplement with and EFFECTIVE amount of omega 3.

    In my view the amount of oil in these capsules isn't sufficiently great to worry about, on the whole vitamin D capsules are really quite small. So I'd rather you took the ones you have already than wait till new one without omega 6 arrive. That said I  try to eliminate every unnecessary source of omega 6 so I wouldn't choose soy, or corn oil vitamin D capsules in the first place.  

    My preference is MCT oil. MCT is very stable so doesn't readily go off. It's easily metabolized and people with inflamed or damaged digestive systems can chew them and absorb the oil/vitamin D in mouth and under tongue. Or capsule can be pierced and contents massaged into the skin preferably where the sun doesn't shine. (UVA degrades D3)

  • Jon Brassey

    4/21/2010 5:15:49 AM |

    You say that most people over the age of 40 have "have lost the majority of their ability to activate vitamin D in the skin".

    Can you point me to a reference on that please?

    Best wishes


  • TedHutchinson

    4/21/2010 1:42:08 PM |

    @  Jon Brassey
    Aging Decreases the Capacity of Human Skin to Produce Vitamin D3
    A comparison of the amount of previtamin D3 produced in the skin from the 8- and 18-yr-old subjects with the amount produced in the skin from the 77- and 82-yr-old subjects revealed that aging can decrease by greater than twofold the capacity of the skin to produce previtamin D3.

    However more recent Vitamin D research confirms providing there is sufficient cholesterol in the skin it is  possible for post menopausal women who spend time outdoors in summer to make a significant  contribution to their 25(OH)D needs (ages in that trial went up to 85yrs) However whether this is sufficient is a matter of opinion.
    I don't think it is viable to expect homes for the elderly ensure residents regularly expose sufficient skin for sufficient time to make sun exposure for the elderly a practicable route though I am sure you can guess, I personally am prepared to make the effort.

    I remember somewhere I've seen a photo of an old style UVB light suspended on the ceiling of a day lounge in an old folks home and they found it helped raise 25(OH)D.I'll try to find it.

    Who, what, where and when—influences on cutaneous vitamin D synthesis Has an interesting paragraph on age and vitamin D production you may read it here.

  • Jon Brassey

    4/22/2010 5:32:43 AM |

    @tedhutchinson thanks for the additional information.

    However, what you report appears to disagree with what Dr Davis said.

    The articles you cite indicate that those over 40 can produce Vitamin D (albeit at reduced rates).

    Dr Davis reported "90% of adults over 40 years old have lost the majority of their ability to activate vitamin D in the skin."

    Yours suggest a 2-fold decrease which - to my mind - is miles away from Dr Davis.

    I'd welcome Dr Davis's comment on this apparent discrepancy (preferably with links to citations)

  • Anonymous

    6/1/2010 11:12:34 AM |

    So last year I got on the Vitamin D wagon and went from 23 to 66 via lots of sun and 4000 IU of supplemental D. Then my doctor told me to cut back, I did to 1000IU to 2000IU per day.

    Just went for my blood test. In 4 months I am back down to 37. Ugh. The "medical" establishment makes it like keeping a healthy level of vitamin D is easy (ie just go for a walk), but it isn't. I suspect either their original information on how easy it is to get vitamin d was totally wrong, or perhaps humans have changed via over 100 years largely inside.

    I did want to say I have been using tabs and not oil based pills. Either they work for me or I take them with oily foods (I take it with my bagel in the morning with Olivio)

  • Freewoman of England

    6/1/2010 2:30:43 PM |

    Olivio?  Margarine?  That stuff kills

    Its 79% rapeseed margarine is Olivio

    I wouldn't touch it with a bargepole Butter is better for you

  • Anonymous

    6/5/2010 5:22:17 AM |

    Very nice and intrestingss story.

  • Anonymous

    7/23/2010 5:48:08 AM |

    why should no adult drink milk?

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    8/2/2010 11:48:36 AM |

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  • charlie salem

    8/24/2010 3:38:54 PM |

    I am epileptic and getting put on a ketogenic diet. The National Hospital our place of (so called) excellence in the UK have all but given up from me and will not test my Vitamin D3. Do the the drugs i take (Keppra and Tegratol) have an effect on D3?
    Charlie Salem www.iamcharliesalem

  • max

    8/26/2010 10:17:50 AM |

    vitamin d can recieve by sunlight?

  • Lucy

    9/12/2010 12:01:10 AM |

    Hello-I believe this is my first time posting a comment here.  

    I just wanted to say, because of what I've been reading, last week during a routine diabetic checkup, I asked my doctor to order a vitamin D test.  She was reluctant.  She said it wasn't something they commonly checked for.  I insisted and she wrote out the order.

    Here's what came back:
    Vitamin D, 25-OH, Total: 14
    Vitamin D, 25-OH, D3: 14
    Vitamin D, 25-OH, D2: <4

    She prescribed 1,000-1,600 of vitamin D a day plus 15 minutes in the sun w/out sunlotion.

    I don't think she knows what she's doing! I found some gel 1,000 capsules an started taking 2,000 a day. The diagnostic notes also say: Optimal levels are > or = 30 ng/ml (Whatever that means!). As for the D3 and D2, the notes say "Reference Range Not established.

    Just wanted to say THANKS YOU! for the information you provide.

  • TedHutchinson

    9/12/2010 8:25:34 AM |

    @ Lucy
    > or = 30 ng/ml (Whatever that means!)
    ABOVE or EQUAL to 30ng/ml

    The reason the < (below) 4ng/ml D2 score was not added to your D3 score is that 4ng/ml is below the test accuracy threshold, so cannot be relied upon.

    30ng/ml (or 80nmol/l)is the level below which actual damage to the skeleton can be measured and is the level at which calcium absorption is generally maximised.
    However some people do not maximise bone mineral density till well above 40ng/ml (100nmol/l).
    But vitamin D enables far more than just calcium absorption and 40ng/ml (100nmol/l) is considered the lowest level at which basic daily needs are met but this isn't sufficient to enable vitamin D3 storage in tissue. To achieve reasonable reserves of D3 a level around 60ng/ml is required.
    At that level breast milk is a vitamin D3 replete food for human babies.
    Although there is a huge individual difference in response to daily D3 supplementation in practice 5000iu/daily only just maintains status above 40ng/ml amounts nearer to the quantity full body exposure creates are required. Hollis & Wagner found 6400iu was required to optimise vitamin D in breast milk.
    Because diabetes is an inflammatory condition the demand on vitamin D resources is greater, most diabetics, (like celiacs) require substantially more D3 to obtain the same results. (Diabetes also increases magnesium usage so bear in mind Dr Davis's magnesium recommendation is generally advise supplementation with the well-absorbed forms, magnesium glycinate (400 mg twice per day) or magnesium malate (1200 mg twice per day))
    From that same post we see Dr Davis says "aim for 25-hydroxy vitamin level of 60-70 ng/ml. This usually requires 6000 units per day, though there is great individual variation in need. As you are diabetic it is likely your need will be greater rather than lesser.
    May I suggest 5000iu/daily may be more appropriate with the possibility of having to take a total of 10 capsules each week to average just over 7000iu/daily if a retest in 3 months shows 5000iu/d + sun still produces too a low a 25(OH)D. WAB666 saves $5 at IHERB whose shipping to UK is cheapest, the same item may be cheaper elsewhere.

  • Ashley

    10/21/2010 6:01:37 AM |

    What if my level of vitamin d is 84.9 ng/mL? Should I still take a supplement?

  • TedHutchinson

    10/21/2010 8:36:28 AM |

    @ Ashleymy level of vitamin d is 84.9 ng/mL? Should I still take a supplement?"
    Really depends where you live.
    If you live in the Southern Hemisphere and will spend more time outdoors with skin exposed to sunshine over the peak summer months then maybe it would be an idea to reduce intake by 1000iu/d or use 2000iu alternate days.
    1000iu/d less should drop 25(OH)D 10ng/ml.
    If you live in the Northern Hemisphere 25(OH)D naturally declines from October until the end of Feb, so continue with the 2000iu and only consider reducing intake by 1000iu/d midsummer next year.

  • Ashley

    10/22/2010 5:13:34 AM |

    Thanks! I live in Tucson, Arizona, and am only 26.

    Perhaps I'll take the 2000 IU every other day?

    Or is taking a steady dose daily better in your opinion?

    Also, do you agree that taking calcium when having this high of a vitamin D level can lead to increased calcium/plaque? Might this explain a high Lp-pla2 test of 193 and a high HS-crp of 3.5?

  • buy jeans

    11/3/2010 3:07:28 PM |

    Likewise, other food sources of vitamin D, such as fish (300-400 units per serving) and egg yolks (20 units per yolk), are inadequate. This makes sense: Humans are not meant to obtain vitamin D from food, but from sun exposure over a large body surface area. And this is a phenomenon that is meant to occur only in the youthful, ensuring that nature takes its course and us older folks get old and make way for the young (i.e., unless we intervene by taking vitamin D supplements).

  • the Wonderer

    11/15/2010 8:30:29 PM |

    Very useful post, but I'm puzzled by this:
    "(Cod liver oil is not the best source of vitamin D, mostly because of the vitamin A content; also a discussion for another time)"

    Are you saying the vitamin A content of cod liver oil is a problem? What about the position of the Weston A. Price Foundation that A and D should be taken in a 5-to-1 ratio of A to D because they work together syngergistically and each protects against possible overdose toxicity in the other. Is there evidence to shoot that contention down?

  • id scanner

    11/27/2010 3:05:11 AM |

    Vitamin D is carried in the bloodstream to the liver, where it is converted into the prohormone calcidiol.It is a fat-soluble vitamin that is naturally present in very few foods. It  is essential for promoting calcium absorption in the gut

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    1/4/2011 5:59:32 AM |

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  • liposculpture guide

    1/13/2011 11:05:55 AM |

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  • Ken D Berry MD

    1/16/2011 6:10:46 PM |

    I am a Family Physician and I'll have to admit that supplementing all of my 50-plus yo patients with Vitamin D is cutting into my income!

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  • paul

    4/29/2011 6:23:40 AM |

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  • Calina Jane

    5/4/2011 10:07:55 AM |

    Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis.

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  • Sandra

    10/27/2011 8:27:57 PM |

    I am a breastfeeding mom and both I and my little one (7.5 months old) have a cold at the moment. I'm not sure how much vitamin D I should take so that my baby would get enough from my milk. Or do I need to supplement her anyway? My levels are 61.8 ng/l and I am taking 5000 IU/day, sometimes a bit more if I forget to take it some days or I feel under the weather. In case she gets the flu or a cold  like she did now, how much can I give her to boost her immune system? How much can I take?