Overdosing on Vitamin D: Side Effects, Toxicity, Symptoms, Poisoning
I promised to write one column about the side effects of vitamin A, vitamin B1 (thiamine), vitamin B3 (niacin, niacinamide), vitamin C, and vitamin D (cholecalciferol). Deficiency in these five vitamins causes death and disability from vitamin A deficiency, beri beri, pellagra, scurvy, and rickets respectively. I’m going to start with vitamin D because there is an urgent need to understand vitamin D better.
Vitamin D is a hormone. It is not found in food in high levels. It is difficult to obtain 1000 IU/day of vitamin D from food. Agricultural workers and lifeguards will produce 20,000 to 50,0000 IU/day in the skin. Hormones are well understood to be remarkably effective drugs. Powerful hormones such as human growth hormone have been shown to have remarkable beneficial effects. This hormone, however, is rarely used because, it is highly dangerous. Steroids to promote muscle growth are known to be dangerous. Hormones for birth control are known to be dangerous. I think it is safe to say that most hormones are dangerous when taken as a drug. Why would anyone expect vitamin D to be different?
Lots of people who expected to be healthy, and worked hard to live a healthy life, are none the less struggling with their health. These folks have tested the "healthy" lifestyles (low fat, low carbs, vegetarian, vegan, exercise three times/week, meditation, religion...) Despite all the testing, I didn't know what to do. It seemed to me that all the theories were wrong. That's what I like about the implications of vitamin D. It has led to a theory that I don't think has been tested. Western life has led us to spend more and more of our time indoors. Indoor life deprives us of sunlight, which causes permanent low levels of two blockbuster hormones - vitamin D and melatonin, and cause permanent low levels of at least one other hormone, various neuropeptides, endorphins, and probably some other things I haven't found yet. Indoor life exposes us to indoor air pollution, and probably is a root cause of other behaviors that are known to be bad for health.
I’ve been hesitant to write this column because I don't want to stop people from taking vitamin D as I believe that vitamin D supplements are doing more good than harm. That said, vitamin D supplements are hormones in a bottle and are obviously dangerous at doses above the upper safe limit of 2000 IU/day set by the Food and Nutrition Board. The other harm the supplements are doing, is sending the message that pills are a safe and effective substitute for sunshine. I'm sure this is true for some people. But what about everyone else? Is the strategy really to use the power of evolution to select for success only children who do the best living in minimal sunlight? Don't believe in evolution these days? One in 6 couples are outright infertile, and the fertility medicine business is booming. Whether from pills or sunshine, optimizing vitamin D will benefit your health. I believe that sunshine is a better way, but not everyone has the luxury of getting regular sunshine, and not everyone needs regular sunshine. Everyone, however, needs vitamin D.
Vitamin D is is acutely toxic in overdose. A single dose, sufficiently large, is lethal. This dose is determined by scientists by feeding dogs and rats. The data from the dogs and rats indicates that a single dose of vitamin D above 150,000,000 IU (150 million IU) is lethal. It is virtually impossible for a consumer to take a dose like this. In fact, vitamin D is so safe that it is sold in bottles without childproof caps. In the past, I purchased large bottles of 1000 IU vitamin D tablets that contain 300 tablets. If I swallowed the entire bottle, I’d be taking 300,000 IU of vitamin D. I’d have to swallow 50 entire bottles at once to reach the lethal dose.
That said, vitamin D is impressively toxic. 1000 mg (a standard dosage for a single vitamin C pill) is a lethal dose for the average person. 1000 mg is 40,000,000 (forty million) IU. The fifty bottles of 1000 IU vitamin D pills mentioned above would weigh in the ballpark of 2500 g. A typical vitamin D tablet weighs 150 mg and is >99.9% filling. This makes safely handling vitamin D challenging. All human processes are subject to error. Some 1000 IU pills will occasionally be formulated with >10,000 IU of vitamin D. The unluckly consumer taking poorly manufactured vitamin D supplements can experience "unexplainable" side effects since everyone usually will assume that the consumer is ingesting the dose listed on the bottle label.
Again, vitamin D is impressively toxic. So much so that scientists specializing in mammalian pest control turned to vitamin D as a safe and effective poison. Just type "vitamin D rat poison" into google and you'll see that you can purchase a rat poison that uses vitamin D as the active ingredient. The poisonous food (the "bait") is typically close to 1 part in 1 thousand vitamin D. Truth can truly be stranger than fiction. While vitamin D3 advocates are writing that vitamin D3 is non-toxic, exterminators are advertising vitamin D3 as a safe and effective poison for killing mice and rats! What makes it so strange is that vitamin D is surprisingly non-toxic while at the same time being an effective rat and mouse poison. It is, in fact, absurdly non-toxic for an acute poison! Honestly, I'm left speechless.
From a practical perspective, death from taking large doses of vitamin D is not a concern (unless you are a mouse or rat and the exterminator is after you!). The practical concern is toxicity caused by ordinary doses of vitamin D, taken regularly. Ordinary doses can build up in the body over time and cause serious illness. The most serious concern is a small increase in the risk of heart attack and stroke amongst the elderly. This concern was raised a long time ago without much evidence to support it. The evidence is reviewed in a book called "The Right Dose, How to Take Vitamins and Minerals Safely." I felt the data was insufficient to warrant inclusion in this blog post. Now, new independent data reaches similar conclusions using a completely different line of reasoning. The older data directly associated the risk of heart attack with vitamin D dosage. The new data associates the risk of stroke with vitamin D dosage. Vitamin D should be expected to act systemically on veins and arteries so it makes sense that if vitamin D increases the risk of heart attacks it also would increase the risk of stroke.
This allegation sounds serious, and it is. However, the reported elevated risks remain associated with high doses of vitamin D from food (1000 IU and less have no association with these problems) and are small increases in risk. Cavities, osteoporosis, repetitive motion pains, and other joint and ligament pains are epidemic amongst the elderly. The hypothesis that these problems can be prevented by sun exposure has never been tested (and never will since a double-blind trial of sunshine is impossible). That remains the second point - there is no evidence of any association between sunshine, stroke, and heart attack. There is a clear message: get vitamin D from sunshine. Sunlight is also known to alleviate/eliminate allergies, to cause special cells in the skin to produce the alpha melanocyte stimulating hormone (so sunshine has been proven by science to cause the produce of at least three hormones!), to cause the production of a couple of neuropeptides, and to cause the release of endorphins. So while you're in the sun getting vitamin D, you'll also be producing a variety of other regulatory chemicals essential for optimal health.
I'll give my view again here a different way. Most people will obtain far more benefits from 0-4000 IU/day of vitamin D from food/supplements than harm. That said, the risks are well documented. There are no well documented cases of vitamin D side effects caused by sunshine producing too much vitamin D in the skin. There are plenty of known risks from overdoses of sunshine. Acute sun overexposure has been practiced as a form of execution.
Back to the well documented side effects. Not surprisingly, the Mayo Clinic is an excellent source I've found on-line for vitamin D side effects. Here is their list:
Late symptoms of severe overdose (emerge after months or years of starting supplements)
High blood pressure
Stomach pain (severe)
Check with your doctor as soon as possible if any of the following side effects occur:
Early symptoms of overdose (emerge within days or weeks of starting vitamin D supplements)
Constipation (especially in children or adolescents)
Dryness of mouth
Increase in frequency of urination, especially at night, or in amount of urine
Loss of appetite
Nausea or vomiting (especially in children or adolescents)
Unusual tiredness or weakness
Late symptoms of overdose (emerge within weeks or months of starting supplements)
Calcium deposits (hard lumps) in tissues outside of the bone
Increased sensitivity of eyes to light or irritation of eyes
Itching of skin
Loss of appetite
Loss of sex drive
Mood or mental changes
Nausea or vomiting
Protein in the urine
Redness or discharge of the eye, eyelid, or lining of the eyelid
What regular dose of a vitamin D supplement will cause side effects? Some people are very sensitive to daily vitamin D dosing. Vitamin D was meant to be gotten from the sun, not from pills. There are no known side effects from sunshine. Side effects from pills are common. This makes dosing recommendations for vitamin D pills particularly hard. Rats have evolved to thrive on incredibly small amounts of vitamin D (hundreds of times less than humans). It is highly likely that different groups of people - and different individuals within a single group of people, have widely different vitamin D needs. Some people are like rats and can thrive in the dark. Others will need regular sunshine to thrive. There isn't enough information yet, and none is needed. Get your vitamin D from the sun. Even if you can thrive in the dark, you can thrive in the sunshine too. Sunshine is generally recognized as safe.
I don't recommend blood testing of vitamin D levels. I don't think anyone knows what it means. If you are getting plenty of sunshine, you are getting plenty of vitamin D. Only a tiny fraction of people will not be able to get plenty of vitamin D from sunshine, and will require supplements. Today, Doctors are measuring blood levels of vitamin D and concluding that low levels require supplements (instead of sunshine). Many of these people are taking the supplements and being harmed. If you don't believe me, read the comment section below.
Stories can be more helpful than lists. The best case history I know of is from an outstanding book called “The Right Dose, How to Take Vitamins and Minerals Safely.” A family of ten all drank regularly from a condensed milk product given to them by a friend. This condensed milk turned out to be a product used commercially by the milk industry to fortify milk with vitamin D. The family members were, on average, most likely taking somewhere between 50,000 and 100,000 IU/day of vitamin D. Here is the relevant excerpt from the case report:
“A male patient was admitted to the Dept. of Pediatrics of the Cook County Hospital because of nausea, vomiting, weight loss, and abdominal pain. Anorexia began three weeks prior to admission, followed by vomiting which was associated with vague intermittent abdominal pain. During the week prior to admission, he started to have severe nausea with frequent vomiting and was unable to attend school. He lost 11 pounds of weight during this period. Muscle weakness and frequency of urination were noted. The child’s 35 year old mother was admitted simultaneously, with severe abdominal pain, anorexia, vomiting, and weight loss of two weeks’ duration. The patient was thin, moderately dehydrated, and appeared chronically ill.”
This case report was a fantastic piece of good luck. Obviously, an experiment like this can’t be designed. It had to happen by accident. The reason it was such good luck, was that it also illustrates why vitamin D toxicity is so controversial. Eight other members of this same family took similar levels of vitamin D over this period and “did not become ill”. Eighty percent of this family was able to take between 50,000 and 100,000 IU of vitamin D for 6 weeks with no ill effects. No wonder the two patients kept on drinking the milk long after they fell seriously ill. Why would they suspect the “condensed milk” when everyone was drinking it and was fine?
According to the book, the symptoms in the case report are “classic signs” of vitamin D overdose. Here’s the write-up on the full list of classic symptoms:
“Nausea, vomiting, loss of appetite, headache, dry mouth, abdominal or bone pain, and dizziness are the classic symptoms of vitamin D toxicity. As the condition progresses, signs of impaired kidney function, such as excessive urination, may arise. Itching, calcification of organs and blood vessels, osteoporosis, and seizures are still other signs that develop at the later stages.” Note the excellent overlap with the more comprehensive list from the Mayo Clinic.
Readers are never going to take 50,000 to 100,000 IU per day of vitamin D. No one recommends sustained doses in this range. So, what’s the best evidence that doses in the range of normal can also be toxic? The best evidence comes from the experience of the British physicians who worked out the recommended daily doses for vitamin D back in the 1930’s and 1940’s. Rickets among babies and toddlers was a major problem in England before the milk supply was fortified with vitamin D. Today, one cup of milk is fortified with 100 IU of vitamin D. The British started out with by fortifying milk at about double this level (200 IU per cup). The program succeeded in eliminating rickets among families that drank fortified milk. Unfortunately, the program made significant numbers of children ill and had to be adjusted down to the current level. Tragically, the present dose doesn’t protect all children from rickets.
The problem with milk fortification is that not only is there a wide range of sensitivity to vitamin D, there is also a wide range of intake. In my opinion, this data suggests that sensitive individuals develop vitamin D side effects from daily use of 1000 to 2000 IU of vitamin D. For example, my son drinks an average of 2 to 3 quarts of milk every day. This means he gets between 800 and 1200 IU of vitamin D from milk and then probably averages over the course of the year another 400 IU/day from sun exposure. The babies in Britain showing up with vitamin D side effect were probably getting plenty of sunshine and drinking plenty of fortified milk. My sense that 1000 to 2000 IU regularly causes side effects was reinforced by a thorough internet search for advice on vitamin D supplement programs from clinicians who help clients put together supplement programs. I found several clinician reports of 2000 IU/day doses leading to problems after months of use. My concerns have been further reinforced by comments below.
If you’ve been reading my column, and reading the information at the Vitamin D Council website, you’ll know that 1000 to 2000 IU/day is often not enough. So, the hard facts are that there is no known dose of vitamin D supplement that provides everyone with full benefits without causing anyone side effects.
I read all the information summarized above before I started taking vitamin D. Sadly, this information about specific symptoms was not very useful to me. What was most useful to me was what I read between the lines. I felt that the words of advice from experienced clinicians expressed a deep-seated unease with vitamin D supplements.
With that unease in mind, I chose to supplement with 4000 IU per day of vitamin D, fully expecting to experience side effects. So, from here on the story is based on my personal experience. The initial draft of my column read, "It will take time to tell how relevant my experiences have been." Time has passed and the feedback from readers indicates that my experiences are relevant.
I have not experienced any symptoms bad enough to require any treatment, or to cancel any plans, or even to go to bed early. I experienced no side effects for three months at 4000 IU/day. For the past 10 months I’ve been alternating between vitamin D abstinence for 1 to 2 weeks and supplementation for 1 day. Some of the time, instead of supplements, I sunbath in shorts at noon for 30 minutes to 1 hour. Every time I take even just one 1000 IU supplement I experience side effects. So, I’m confident that for me, the following side effects are caused by vitamin D. I updated this item in December, 2009, a second time in October, 2010, and now a third time in May, 2011. For the past 29 months I have gotten almost all my vitamin D from sunshine. I lie in the sun at noon for between 5 and 20 minutes 9 out of ten sunny days here at latitude 40 N. Many claim that there is insufficient UV intensity at 40 N in the winter to produce vitamin D. This view is incorrect. It is possible to get UV index data from nearby weather stations at popular weather websites. Where I live, the UV index ranges from 3 at the winter solstice to 11 at the summer solstice. This means that it takes four times longer to get equivalent UV at solar noon in the middle of the winter. There are on regular occasions multiple successive days when I can't get into the sun in the middle of the day. At first I responded by taking one or two 1000 IU tablets during these days. Each time I experienced unpleasant side effects from the supplement strongly suggesting that the sunshine is keeping me on the edge of overdose. So I completely stopped taking supplements. On several occasions I came down with a cold during these short periods without sun or supplements. In response, I've been finding ways to get even more vitamin D from the sun. Whenever I smell even the whiff of a cold, I now get into the sun several times in the same day. 5 to 10 minutes of noontime sun is all I can manage in the summer without becoming uncomfortable (feeling like I'm starting to overheat my skin). I have found, however, that by staying out of the sun for just an hour enables me to sun again for several minutes without any discomfort. On an extreme day I have done this four times. A big surprise for me was that the extra sun exposure has not made me any more tan. Despite getting lots of sun, I maintain only a faint tan. This is what I want since I'm trying to make alot of vitamin D. More recently I bought a sunlamp so that I can get vitamin D from light whenever I feel I could benefit from more vitamin D and I don't ever feel the need to take another supplement. I don't recommend the use of sunlamps and tanning beds because I don't have any information about the safety of this approach, and I only use the sunlamp when there is no sunshine.
Again, I have not found any prior documents asserting that side effects from vitamin D supplements are related to the amount of vitamin D made from the sun. So I wasn't expecting to suffer from vitamin D supplements as I got more vitamin D from the sun. But, I did. As time has passed, I'm getting more and more sun with fewer side effects. I still occasionally take a supplement. I took one just last week and felt the side effects immediately. The impact of the supplement was gone in less than 48 hours. I've come to the conclusion that some of the vitamin D side effects I experience, I only get when I am fighting a cold. I'm not sure these should really count as side effects since they may be how cold symptoms feel to people like me getting plenty of sunshine.
Enough of that. Here are the side effects that I feel aren't well described on the Mayo Clinic list:
1) Irritable lungs. For example, when I breath in alcohol vapors I need to cough. When I drink my coffee in the morning I need to cough (probably a reaction to the caffeine).
2) Sensation in the teeth. I feel my teeth. I can’t decide if this is good or bad. What is definitely bad is that when I switch from warm food to a cool drink I get nasty electric shocks in my teeth. Rarely I have experienced tooth-ache like pain as a result of chilling my teeth with cold air or cold food. This pain lasts for 10 or fifteen minutes.
3) Bone pain in the fourth finger on my left hand. This is very strange. Often within minutes of taking a vitamin D supplement, I notice a slight pain in the fourth finger of my left hand and nowhere else. I first experienced this feeling while taking 4000 IU/day and, at that dose, the pain got quite severe on the last day I took that dose.
4) Nausea with fatigue.
5) Ringing ears.
6) Chest pain and heart sensations. I find this to be the worst and most alarming side effect. It caused me to shun all forms of vitamin D for two months. I went for a full cardiac workout and blood testing. I was informed that I’m in terrific health. Like the bone pain, for me this side effect is more severe from supplements than from sunshine.
7) Insomnia. Vitamin D will make me fatigued during the day while at the same time it sometimes causes me to wake up near 4 am in the morning. I have alot of trouble falling back to sleep and sometimes get up between 5 and 6 instead of between 6:30 and 7:00.
8) A bad mood. Vitamin D is known to have psychological effects. It is supposed to improve mood. I’m really uncomfortable with listing this as a side effect because it is so subjective. The other side effects are sufficient to put me in a bad mood. But my gut tells me it is worse than that and that the excess vitamin D is actually causing a feeling of doom. As time passes, I've become aware of more reports of feelings of doom.
The following side effects have just emerged in April 2009. They are perfectly described on the Mayo Clinic list:
9) Discharge of the eye, eyelid, and lining of the eyelid
10) Increased sensitivity of eyes to light or irritation of eyes
These early side effects are totally harmless if recognized as such and acted upon. When vitamin D supplementation is stopped, they fade away in a few days. So, it isn’t that hard to manage as long as you are willing to pay attention to how you feel and not worry about the minor discomfort.
Unfortunately, even here I have to add a word of caution. Staying out of the sun and stopping vitamin D supplements from bottles is not enough for everyone. There is a small subset of the population that drinks a lot of milk. Each cup of milk contains 100 IU of vitamin D. One quart is 400 IU – a large fraction of the 1000 IU tablets that are causing me trouble.
Every report I was able to read about vitamin D claimed that overdosing from sun exposure is unknown. This remains true. It is one of the reasons I'm overdosing. I simply can't believe that every expert writing about vitamin D side effects is wrong. Especially when for me, overdosing from the sun is easy. Amazingly, I have to conclude that almost no one has tried to overdose from the sun (avoid tanning and get into the noon sun for 5 to 30 minutes of full body exposure). I experience a different severity order from the sun than from the supplements. The really distinctive signs – my finger and my heart – are almost unnoticeable from sun overdose. The fatigue and nausea are much worse – and much harder to say with certainty are from vitamin D and not a bad breakfast or a virus or any of the hundreds of other causes of nausea and fatigue. The only side effect with similar severity from both the sun and supplements is the feelings in my teeth. Since I first wrote this the feelings in my teeth have subsided and I rarely get shocks from drinking cold fluids. Now my eyes are more sensitive than my teeth. Maybe this will fade with time to be replaced by yet a different first side effect. It seems impossible to "line out" a vitamin D dose. After three years of wrestling with supplements and sunshine, I've rid myself of some of the most annoying early side effects only to have them replaced by different side effects. I'm now past three years, and am finally having less trouble with side effects from sunshine. As I mentioned above, I discovered that some "side effects" are actually caused by cold viruses and not the sunshine. Most of the others have stopped altogether, or are so mild that it's hard to call them side effects. I'm truly amazed that this process of continual change has gone on for over three years.
Vitamin D is an amazing nutrient. Used in optimal doses, it has incredible potential for improving human health. The early side effects of vitamin D are mild and a blessing. They enable you to find the maximum dose you can take without experiencing the terrible side effects described in the case report and comments below. Don’t let fear of side effects stop you from enjoying the full benefits of vitamin D.
Afterward: I track the impact of what I write by searching on Google. When I type "vitamin D side effects" into Google, this column usually comes up in the first 30 hits no matter what computer I search from. The success of this column challenges paradigms about influence and credibility, and I believe there are some general lessons to be learned. Effort and experience can lead to excellence without formal training in an area. I didn't become a world expert in vitamin D side effects by studying books and papers (although I studied and studied and studied books and papers), or by being unusually smart. I became an expert because I'm in desperate need of methods to strengthen an immune system unusually vulnerable to the common cold. As it is, despite all the benefits I get from vitamins A, B1, B3, C, and sunshine, until very recently I have still been frequently ill - and sometimes seriously ill for short periods. It has been to save myself that I have become an expert user of vitamins A, B1, B3, C and sunshine. For the first time in 15 years, I've become optimistic that I may, indeed, at long last, have saved myself. I believe that sunshine, indeed, has been the key, but not by producing vitamin D alone. Sunshine is also responsible for regulating the pineal gland. The pineal gland's main function is to control the circadian rhythm by secreting melatonin. The amplitude of the melatonin "wave" is a function of the difference between the brightest light in the day and the night time darkness. Four months ago I learned about this and started to stare at the sky whenever I was outside during the day. When sunning at noontime, looking up at the sky is painful because the light is so intense - that's why most people are wearing some kind of sunglasses. Amazingly, almost as soon as I started I began to sleep much better at night. Quality sleep is essential for a normal metabolism and for enabling certain aspects of healing. I haven't had much in the way of a cold since I started staring at the sky, and have been flying on airplanes without fear for the first time in over 20 years. Sunlight produces at least one more hormone, causes the production of several neuropeptides, and stimulates the release of endorphins. I expect to learn of yet other positive health effects. These results have me shocked, and, frankly, frightened. I don't know anyone who stares at the sky to improve their circadian rhythm and improve their sleep quality. Everyone I know avoids staring at the sky and a majority wear dark glasses in the summer. Everyone I know is spending more and more time inside, and is becoming less and less tolerant of heat and cold (and therefore spending more and more time fully dressed). I'm staring at the sun and going out in shorts and a T-shirt in an ever wider temperature range. These are polar opposite behaviors to the mainstream. They can not both be optimal. Either I'm right and everyone else is wrong, or everyone else is right and I'm wrong. But I can't stop myself from staring at the sky because I have really powerful feelings telling me that I need to stare at the sky to remain healthy. If I'm right, I am living amidst pandemic deficiency, and I have knowledge and experience from which most other people can benefit. I hope that this post on vitamin D enhances my credibility, and that you'll consider benefiting from my struggles by using sunshine, antibiotics and vitamins with care to enable your growing children to reach their full potential, and to prevent obesity, diabetes, hypertension, osteoporosis, and heart disease from afflicting yourself and your loved ones.