Posted Jan 11 2010 on his blog http://heartscanblog.blogspot.com/2010/01/getting-vitamin-d-right.html
and cross posted on wellsphere http://stanford.wellsphere.com/heart-health-article/getting-vitamin-d-right/943885
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 believe this mistaken belief is 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 as of Jan 15
Anonymous Peter S said...
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
January 11, 2010
Anonymous Anonymous said...
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.
Anonymous zach said...
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?
January 11, 2010
Anonymous AJ said...
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?
Anonymous LynP said...
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.
Blogger mongander said...
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.
January 11, 2010
Blogger TedHutchinson said...
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 traditionally 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.
January 12, 2010
Blogger TedHutchinson said...
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.
January 12, 2010
Blogger Henry North London said...
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 any other 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 off with the gel caps to bump it up to 83ng/ml
January 12, 2010
Blogger TedHutchinson said...
@ 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.
January 12, 2010
Anonymous Rayboy said...
There are five different forms of Vitamin D. http://en.wikipedia.org/wiki/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.
Blogger pmpctek said...
"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.
January 12, 2010
Anonymous Anonymous said...
Dr.,
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.
RESPONSE 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.
Blogger TedHutchinson said...
@ 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) {UV winter}
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.
January 13, 2010
Anonymous Anonymous said...
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. 
January 13, 2010
Blogger Dr. William Davis said...
Anon--
25-hydroxy vitamin D is the preferred test, the "repository" form prior to conversion to the 1,25-dihydroxy form.
January 13, 2010
Anonymous zach said...
jpatti,
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.
January 14, 2010
Blogger Daniel said...
There is also Melamed's study showing a sharp increase in mortality above 50ng/ml or so. Small sample size and residual confounding probably, but worth considering nonetheless.
I added: You can get extensive information on vitamin D at my conventional web site: http://www.henrylahore.com/VitD.html. You will soon also have a wiki for sharing vitamin D information
comments on previous post ___
November 09, 2009
Anonymous Lere said...
Vitamin D and homeostasis " a homeostatic mechanism keeps the level of vitamin D in our bloodstream within a certain range. When UV-B light is always intense, as in the tropics, the level seems to be 50-75 nmol/L in young adults and progressively lower in older age groups. The more sunlight varies seasonally, the more the body will produce vitamin D in summer in order to maintain at least 50 nmol/L in winter—a level well below the recommended minimum of 75 nmol/L and even further below the 150 nmol/L now being advocated by vitamin-D proponents.
This homeostatic mechanism breaks down if we daily ingest 10,000 IU of vitamin D or more (Vieth, 1999). It seems that the human body has never naturally encountered such intakes, at least not on a continual basis.
In a recent review article, Robins (2009) presents evidence for a second homeostatic mechanism. Even when the level of vitamin D varies in the bloodstream, the second mechanism ensures that these divergent levels will translate into the same concentration of the biologically active 1,25-(OH)2D metabolite."
Blogger Dr. William Davis said...
Hi, Valerie-
I am definitely continuing to advise vitamin D normalization for nearly everybody, including those with aortic valve disease.
I now have about 30 people who have normalized vitamin D and have aortic valve disease. The overall trend is a dramatic slowing of deterioration. Vitamin D does NOT cause worsening unless you take it to toxic levels. That is what is causing the confusion: Rat studies in which toxic levels of vitamin D were used to cause aortic valve disease.
Anonymous Anonymous said...
Dr. Davis,
I've tried 3 different forms of supplemental Vitamin D(dry tabs, gel caps and now liquid drops). For some reason I seem to experience slight tightness of chest and shallow breathing after I take any form of vitamin D. The higher the dose, the more pronounced the side effects are and for a longer duration (last weekend I took 4000iu's and it seemed to last for most of the day).
Mike
November 14, 2009
Blogger Dr. William Davis said...
Mike-
Once in a while, I'll see somebody with sternal (breastbone) awareness of vitamin D deficiency or replacement, both resulting in pain. While harmless, it can be very frightening.
However, you might still want to consult your doctor about this. Hopefully, he/she understands how important vitamin D replacement is.
Blogger Neonomide said...
Heike-Bischoff-Ferrari et al. (2008):
http://www.ajcn.org/cgi/content/full/84/1/18/F1
As you can see, over 50 year old white-skinned persons who had higher than 100 nmol/l had _lower_ bone mass density than those about at 100 nmol/l.
I think this should be taken into consideration when determining optimal 25(OH)D levels, don't you think ?
Full text here:
http://www.ajcn.org/cgi/content/full/84/1/18
November 15, 2009
Anonymous Anonymous said...
Dr. Davis, I've been supplementing 10k iu per day for nearly 1 year using a gel cap supplement. I still only managed to achieve a level of 52 ng/ml. Is it safe to take a higher dosage. In your practice have you found this to be common. I have had my gallbladder removed and use nexium for GERDs. Otherwise im healthy 50 year old male. Thanks for taking the time to read.
November 16, 2009
Blogger Olga said...
Hi Dr. Davis:
I had an unnecessary hemithyroidectomy about 5 years ago for a benign goiter after my second pregnancy (both winter pregnancies) and have felt unwell ever since. I could never find a dose of synthroid that would work well. I would need a dosage adjustment upwards in the late fall and then in the spring I would feel hyper and need to lower the dose. This went on for 3 years in a row and I finally asked my Dr. if this could be due to Vitamin D since it's the only seasonal variation that made sense to me. She of course said that was unlikely.
I did lots of reading on the topic and found that many people that have half a thyroid don't need supplementation, so I asked her if I could try going off the meds to see if my thyroid could make enough hormone on it's own. Other than being tired and having heavy periods I felt not too bad. At 3 months I was iron deficient so I started consuming liver once or twice per month for about 3 months and started feeling ill with joint pain, digestive problems, fatigue, insomnia. It took me another 6 months to figure out that people who have familial hyperlipidemia have a tendency to overdose on levels of vit A that would be fine for most people. Here's are a few of the papers that finally gave me some answers:
http://www.annals.org/cgi/content/abstract/105/6/877
http://www.ajcn.org/cgi/content/full/71/4/878#R25
And again the symptoms worsened in the fall. I developed a cold that lasted 4 months! Finally I insisted my DR. check my vitamin D level and in September it was 72 nmol/L. She was surprised and put me on 1000 IU of vit D3. Over the next year I waffled between taking synthroid or Armour and going off it because I felt so awful and didn't know what was wrong. I think the Vitamin A was confounding the recovery process. A major breakthrough came a couple of months ago. I was on the lowest dose of synthroid (in the fall of course), my thyroid function had improved enough over the past 2 years that the lowest dose was enough, and I started taking 5000 IU of vitamin D. Within 2 weeks, I started having severe hyperthyroid symptoms. I told my Dr. that I thought the vit D was improving thyroid function and that I wanted to go off the synthroid yet again. Within 2 weeks the hyper feeling slowly subsided and I am waiting 3 months before having my thyroid levels and vit D checked. My only remaining symptoms are joint pain (less now than a year ago), mild fatigue, insomnia, and constant hunger despite being on a low carb diet (which made me feel great before the surgery). My mood is much better and my mental clarity has improved. Over the past year my TSH off medication has dropped from 12 to 4. I am hoping that in 3 months or so it will be almost normal.
Here is one of a few papers I found about low levels of Vitamin D following a hemithyroidectomy:
http://content.karger.com/ProdukteDB/produkte.asp?Doi=182696
I had my iodine levels tested and they were found to be normal. I wonder now if the nodule was cause by low levels of vit D during two winter pregnancies along with a prenatal supplement which was high in Vitamin A relative to Vitamin D in a Vitamin A toxicity susceptible person. I found a few papers on-line which suggest vit A can be a cause of thyroid goiter.
Thanks for this excellent blog.
December 02, 2009
Anonymous Di said...
I am so pleased to have found this blog! I was diagnosed with mild arotic valve stenois and afraid there was no treatment approach, until reading about Vitamin D here. I have am taking between 1,000 - 2000 i.u. of D3 per day for reducing fatigue and improving calcium absorption(I also have osteopenia and take Fosomax once a week; am age 59.) Dr. Davis, how much more Vit D can I safely take? I do not know how to to calculate the ng/ml levels that I am reading about here. How would you suggest I get started with this approach?
December 21, 2009
Blogger DougCuk said...
The only way to tell how much Vitamin D3 supplement you need to take is by a blood test - either via your doctor or take a look at this website www.grassrootshealth.net/ which offers cost price blood tests.
I have put together a summary of current advice on Vitamin D blood levels and guidance on response to supplement intake: www.stargateuk.info/vitamind/Blood_Levels.htm
For a general overview of Vitamin D health benefits take a look at my website: www.stargateuk.info/vitamind