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Vitamin D and Optimal Health

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According to recent research, at least half of the U.S. adult population may have low blood levels of vitamin D (Journal of the American College of Cardiology, Dec. 9, 2008). One analysis suggested that the number is closer to three out of every four (Archives of Internal Medicine, March 23, 2009).

Perhaps even more alarming, a study published in the journal Pediatrics showed that 9 percent of the 6,275 children tested were vitamin D deficient (online, Aug. 3, 2009). That translates to more than 7 million American children. And an even more astounding number of kids may have levels that, while not deficient, are still too low: roughly 50 million.

Low Vitamin D Linked to

  • Arthritis
  • Asthma
  • Cancer
  • Colds and the flu
  • Dementia
  • Depression
  • Diabetes
  • Falls in the elderly
  • Heart disease
  • Infection
  • Hypertension
  • Kidney disease
  • Muscle pain
  • Osteoarthritis and osteoporosis
  • Rickets
  • Stroke

For most of the history of human existence, getting enough vitamin D was not a problem. That’s because we once spent much more time in the sun, and vitamin D is a nutrient that our body makes from sunlight.

Gradually, though, somewhere between the time when we stopped needing to hunt and gather our food and the present, when we stopped needing to go outside to do much of anything, vitamin D deficiency has become a real issue, and one that many researchers think is much more widespread than we might think.

Consider the fact that the vast majority of us now spend almost all day indoors, staring at a computer screen. Then add this compounding problem to the pile: we have now been hearing from dermatologists for decades that direct exposure to the sun is our enemy. That too much sunlight will cause everything from unsightly wrinkles and prematurely aged skin to life-threatening cancer. Sunscreen manufacturers have produced ever-more powerful products to block out even the most blasting of sunrays. And cosmetics makers have come up with increasingly convenient and convincing products for mimicking a “healthy tan.”

Now let us be clear: of course doctors are right, and of course too much UV exposure is hazardous. You should absolutely use a good, strong sunscreen when you plan to spend all day at the beach, or hiking a mountain, lounging around the pool, or any other place where you’re likely to get an intense, prolonged hit of super-sun. And you should absolutely avoid frying yourself in a tanning bed, as there is an overwhelming body of evidence to suggest that it strongly increases the risk of life-threatening skin cancers—likely without even boosting vitamin D levels. So the only “benefit” is cosmetic. A very small benefit indeed when your life is on the line, especially considering how believable many fake tan products are these days.

But now it’s time for us to present what is at stake. When levels of vitamin D drop too low, people are at an increased risk of many serious chronic health problems, like diabetes, osteoarthritis, and a wide range of common cancers. Recently, we’ve also learned that premature death due to heart disease and stroke also appear to be linked to vitamin D deficiency. In 2009, Finnish researchers announced their findings from a study conducted on more than 6,000 middle-aged men and women for over 20 years. They found that those with the lowest blood levels of vitamin D were 25 percent more likely to die of a heart attack, and twice as likely to die of a stroke (American Journal of Epidemiology, October 15, 2009).

Another study looked at vitamin D and race. Darker skinned people tend to have lower levels of vitamin D than people with pale skin. They also have a greater chance of dying from strokes and heart attacks. There are many possibilities for the disparity, but differences in vitamin D levels may be one contributing factor. In the study, those with the lowest vitamin D levels were 40 percent more likely to die over the next 12 years than people with the highest levels (Annals of Family Medicine, Jan/Feb, 2010).

Compare those alarming statistics to the benefits vitamin D can have. It can help boost the immune system, strengthen bones, and decrease the likelihood of getting everything from high blood pressure to diabetes to heart and kidney disease to a wide range of cancers, or from suffering a heart attack or stroke.

Yet despite all of its proven health benefits, and the risks associated with levels of vitamin D that are too low, some controversies around vitamin D deficiency still remain. Two questions stand out: who qualifies as “deficient”? And how should low vitamin D levels be boosted?

How to Tell if You’re D-ficient

Signs of Vitamin D Deficiency

Symptoms of vitamin D deficiency may include:

  • Asthma
  • Depression
  • Digestive upset
  • Low energy, sluggishness
  • Moodiness
  • Muscle pain or weakness
  • Sleeping problems
  • Weak bones, bone pain, or fractures
  • Weight gain

These symptoms can be subtle and hard to detect, and some people with vitamin D deficiency will have no symptoms at all. The only accurate measure of vitamin D deficiency is a blood test.

Home Blood Tests

The Vitamin D Council sells a couple of different blood tests that consumers can use themselves at home, and then send in to have analyzed. (Please note that such testing is illegal for residents of NY State, as mentioned on the Vitamin D Council website.)

The tests aren’t cheap: a single test (at the time this guide was published) is $65 plus shipping and tax, or a “Multi-Test” set of 4 tests can be purchased for $220, plus shipping and tax through the Vitamin D Council website: www.zrtlab.com/vitamindcouncil.

The same laboratory also processes tests sold (for $68 each) at the website: www. virginiahopkinstestkits. com/vitamindtest.html.

The only true gauge of vitamin D deficiency is with a blood test, called 25 hydroxy vitamin D. Typically, this test is performed at the doctor’s office, which is still the most reliable method. Your doctor should be able to tell you for certain whether or not your vitamin D blood levels are falling within a safe range, or if they’ve dropped low enough to require treatment.

But there has been some controversy about what qualifies as an optimal level. The experts we’ve talked with seem to agree that 20 nanograms (ng) of vitamin D per milliliter (ml) of blood is the cutoff for deficiency. That is a very low level, however, and there is unfortunately no such consensus about what number is best, or how high a reading is too high. The range for what is appropriate most likely falls somewhere between 30 and 50, but it may reach up to around 80.

Another stumbling block on the road to finding out whether or not you’re D-deficient could be your doctor. Most doctors have only become interested in testing for low levels of vitamin D within the past few years, and there are still many physicians who are reluctant to order the necessary tests. Some may not yet have seen the medical research showing how pervasive vitamin D deficiency has become for both children and adults, while others may think that the problem has been exaggerated. (Consider, for instance, the headline of a New York Times “Well” blog article from Feb. 1, 2010: “Vitamin D, Miracle Drug: Is It Science, or Just Talk?”)

In the event that your doctor shows some hesitancy about ordering you a vitamin D test, it’s possible to take a blood test at home. (For those who are interested, there is information in the left sidebar about some home-testing options.) The results of a home test may spur your doctor to action.

But home testing kits aren’t cheap— and they may also not be as accurate as a doctor’s test. Your doctor and the phlebotomists and lab technicians she relies on are trained to get precise results. We think it’s always best, when possible, to get your testing done at the doctor’s office.

Besides the results of a home blood test, here are some other possible signs that you may have blood levels of vitamin D that are too low: muscle and joint pain; fragile bones and fractures; tiredness, or generally feeling logy; weight gain; irregular sleeping cycles; symptoms of depression or moodiness; frequent colds or infections, possibly including vaginal infections for women (The Journal of Nutrition, Apr. 8, 2009); stomach upset, possibly including vomiting and diarrhea.

Of course these symptoms could also be the result of many other conditions or disorders. For instance, lethargy and feelings of depression could be an indicator of an underactive thyroid gland. Weak bones are often caused by osteoporosis. Frequent colds and infections could be the result of an immune disorder. And an upset stomach could be a sign of any number of issues.

So just suffering from one or more of the problems in the list above (and in the sidebar at the left) does not mean that you are necessarily vitamin D deficient. That is why it is so important to talk to your doctor about any possible concerns you may have. (Especially if you are suffering from any of these symptoms—let alone all of them!)

And remember, if your physician is absolutely unwilling to perform the 25 hydroxy vitamin D test despite your repeated requests, it is always possible to get a second opinion (or a new doctor).

But your doctor should always remain in the loop about what health questions you have and what problems you may be facing, as a deficiency in one area may help explain problems or complications somewhere else. The bottom line, as always, is that good communication with your physician is essential to good health care.

Vitamin D deficiency can be extremely serious, and may need to be treated with prescription-level doses of vitamin D. It will certainly require ongoing monitoring and testing by your doctor.

But with respect to levels that are only slightly low, one bright spot—literally!—is that treatment seems to be relatively easy, cheap, and do-it-yourself. All it takes, more or less, is a little bit of regular sunshine, and possibly some supplementation with vitamin D2 or D3.

Upping Your Intake

Lucky Number 13

In a study conducted in the UK (Journal of Investigative Dermatology, online Jan. 14, 2010), researchers exposed fair-skinned men and women to short “sunbaths” of midday summer sun: 13 minutes on average, 3 times per week, for 6 weeks, wearing T-shirts and shorts.

This amount of sun raised participants’ average vitamin D levels from 18 to 28 ng. (All had low levels to begin with, and none were taking supplements.) The researchers concluded that “future public health messages could promote regular short exposures to midday summer sunlight” for people without skin cancer. In North America, the amount of time might need to be 9–16 minutes, but before sunburn.

Just Say No to Tanning Beds

A considerable body of evidence has accrued to show that tanning beds lead to an increased risk of skin cancer. Some proponents of the devices have argued that they may boost vitamin D levels, thus decreasing the cancer risk. But a study published in Dermatologic Therapy (Jan. 23, 2010) indicates otherwise. Its authors note that “most tanning devices primarily emit ultraviolet A, which is relatively ineffective in stimulating vitamin D synthesis.” (It’s ultraviolet B that does the trick.)

They conclude: “Indoor tanning represents an avoidable risk factor for skin cancer, and education of the general public as well as the enactment and stricter enforcement of indoor tanning legislation are a public health imperative.”

Vitamin D is unique among vitamins in that there isn’t a whole lot of it in many foods. (For a short list of foods and beverages that contain vitamin D, see the next page.)

Our body primarily depends upon exposure to sunlight for production of this essential nutrient. One way to increase your vitamin D production is simply to spend a little more time in the sun.

Getting Enough Sun

It is probably not a huge shock that many of us aren’t getting enough regular sun exposure. Between our long work hours glued to the computer screen, and our leisure-time activities in front of other screens, most people don’t spend nearly as much time outdoors as was once common. And now when we do play in the sun, we tend to lather up with sunscreen to protect ourselves from the risk of getting skin cancer.

But while it may not come as a surprise that some of us are sun-deprived, especially those in northern climes with long, dreary winter months, consider this: one study showed that even in southern Arizona, the land of abundant sun, as many as a quarter of the adults tested had dangerously low levels of vitamin D (American Journal of Clinical Nutrition, March, 2008).

When it comes to getting enough sun in your life, balance is key. You don’t want to get so much that you burn, or bump up your chances of developing skin cancer. (Indeed, anyone who has skin cancer or is at a high risk of developing it should get their vitamin D levels up in other ways.) But you also don’t want to get so little that you’re not doing yourself any good.

The general consensus among experts is that about 10 to 15 minutes of sun exposure several times a week in the warmer months is about right for fair-skinned people. (Dark-skinned people need a bit more; expert Dr. James Dowd told us his African American patients’ readings tended to be 10 to 15 points lower than his European American patients’.) Be sure enough skin is exposed to see a benefit. Wearing a T-shirt and shorts should work if it’s warm enough, or if you’re at the beach or pool on a very hot day, don’t be afraid of a swimsuit.

But just exposing your face is probably not enough, especially as many people, women in particular, often wear face lotions, creams, or cosmetics that may have some sun protection built in.

If you take your regular “sunbath” as an opportunity to do more than simply sunbathe—walk or jog around the block, for instance, or do a little gardening—then your health will benefit in other ways!

Unfortunately, with the exception of people who spend their winters in warm, sunny environs, it can be downright impossible for many of us to get an adequate amount of sun in the darker months. And in case you were considering braving the cold in Boston or Detroit and stripping down to your skivvies in the winter sun, don’t bother! Those scanty rays are not strong enough to make the torture worth your while.

SAD? Or Just (D)own?

Seasonal Affective Disorder, appropriately shortened to SAD, is another name for the winter blues.

There are many possible causes, but one leading hypothesis among experts is that the relative lack of sunlight during the colder months is a major contributing factor. It’s possible that sun affects neurotransmitters, like serotonin, which could make people feel pretty bad. And it’s probably also true that fewer opportunities for exercise in winter could make us feel unhappy, too. But one other potential culprit could perhaps be that people’s vitamin D levels tend to dip down at the same time the barometer does.

Consider some symptoms of SAD: depression, low energy, and moodiness. These are similar to signs of D deficiency. And one of the most common and effective treatments for SAD is light therapy: doctor-recommended exposure to special lights that are supposed to mimic sun. (According to expert Dr. Michael Holick, only the Sperti brand lamp produces UVB and therefore can boost vitamin D.)

SAD is a real and serious clinical problem, and we don’t mean to suggest that it simply points to a vitamin D deficiency. But it may be that low D is one of the issues SAD sufferers—and others with the winter blues—face.

Vitamin D Supplementation

D2 vs. D3

It may sound like a science fiction movie face-off, but we’re really only talking about the differences between vitamin D2 and D3.

D2 is derived from plant sources, and D3 comes from animal sources, but otherwise, D2 and D3 are essentially just slightly different forms of the same vitamin. (D3 is somewhat more potent when taken as an oral supplement.)

This is different from the various B vitamins, for example (B1, B2, B3, B6, B12), which are actually different vitamins.

Supplement vs. Sun

Dr. Michael Holick, an expert on vitamin D, has told us that the main difference between getting vitamin D from the sun vs. a supplement is that when we get it from the sun, it lasts about two to three times longer in the body.

There are many people who may not be able to get all the vitamin D they need from the sun. In the winter: most North Americans and Europeans. Anyone who works a night shift, and for that matter, many people who work long “day” shifts, which involve not getting out to see much of the day. Not to mention anyone who has had skin cancer or is at a high risk of getting it.

For all of these people, and many others, getting additional vitamin D in the form of a nutritional supplement may be one answer to the problem of deficiency.

Over the past several years, vitamin supplements have been taking a real beating in the press because they’ve failed to live up to all of their promised hype. That has made some doctors understandably wary of recommending that their patients take each of their vitamins in separate supplements. Instead, they often just suggest a well-rounded diet and a multivitamin, to round things out.

But supplements for vitamin D seem to be one shining exception to the rule.

A team of researchers in Boston gave 86 people who were deficient in vitamin D 50,000 IU (international units) of vitamin D2 once per week, and within 8 weeks, the deficiencies were corrected. After the initial 8-week period, they prescribed participants a maintenance course of 50,000 IU of D2 every other week, which appeared to work well for most of the patients (Archives of Internal Medicine, Oct. 26, 2009).

Fifty-thousand units of anything each week may sound like an awful lot, and it is. But that is what many doctors prescribe to correct a serious vitamin D deficiency. As long as it is monitored, that is not an unreasonable amount for a limited period of time. Although it is not a dose that anyone should take on his own, unsupervised by a physician.

For those of us whose vitamin D levels are not deficient or even dangerously low, 1,000 to 2,000 IU per day is not an inappropriate amount, especially in the winter months. But do keep in mind that you may be getting some vitamin D in what you’re eating and drinking (see the list below), so don’t go too overboard with supplementation if so.

Eating and Drinking Your Way to More Vitamin D

IU vs. MG

“IU” stands for “International Unit,” which is a measurement used in pharmacology for an amount of a substance.

Many of us are used to seeing medication measured in “mg,” or milligrams. IU and mg are not the same.

The difference, essentially, is that IU is used to measure how much biological effect a given substance might have, whereas mg is just a standard measure of mass. IU is typically applied to things like vitamins, hormones, vaccines, blood products, and some drugs.

We’ve already listed a lot of known scientific factors for why kids and adults today are presenting with record numbers of vitamin D deficiency: changes in lifestyle that have led to spending less time in the sun; better sunscreens, etc.

But maybe there is another factor that has been overlooked by the scientific research community: grandmothers.

Many of our readers have told us that they can remember being chased around the house when they were children by mothers or grandmothers bearing tablespoons of foul-tasting cod-liver oil.

Well, it turns out that grandma (or ma, or grandpa, for that matter) may have been right (again).

Over the past few years, evidence for the benefits of fish oil have been piling up. Among the problems and conditions that fish oil may help to prevent are: high cholesterol, joint pain and arthritis, diabetes, heart disease, macular degeneration, depression (possibly even psychosis). . . and vitamin D deficiency. Fatty fish are a good source of vitamin D. Wild Alaskan salmon, for example, contains roughly 500 to 1,000 IU in a serving.

Although the list is fairly short, there are a few foods and beverages that do contain vitamin D, including some that have had vitamin D added. (Keep in mind that many of the large fatty fish listed below may also have high levels of mercury, so they shouldn’t be eaten more often than a couple of times per week.)

Foods & Beverages that Contain Vitamin D

  • Cod liver oil (check the label)
  • Herring
  • Catfish
  • Salmon
  • Trout
  • Halibut
  • Sardines
  • Mackerel
  • Tuna
  • Milk/soymilk fortified with vitamin D
  • Orange juice fortified with vitamin D
  • Cereal fortified with vitamin D
  • Some brands of tofu

Vitamin D Deficiency and Kids

The Return of Rickets

The authors of an article published in Pediatrics (Aug. 1, 2008) noted: “there has been a reappearance of rickets from vitamin D deficiency in recent decades.”

There aren’t any exact figures on how widespread the problem has become in North America and the UK, but the authors do think they know what’s causing it: “The increasing numbers of reports of rickets in Western industrialized nations are related to…breastfeeding without…vitamin D supplementation… decreased UV-B exposure (particularly in dark-skinned people), and the excessive use of sunscreen.”

They suggest using a low threshold for determining D insufficiency in kids “given the growing knowledge about effects of vitamin D not only on bone mineral metabolism but also on the immune system and in preventing various kinds of cancer.”

Deficient from Birth

Dr. Holick told us about a study that found that 76 percent of new mothers and 81 percent of newborns were deficient in vitamin D at time of birth. He also told us that D deficiency in utero and during the first year of life may set kids up to have serious chronic diseases later on.

It can also cause problems for pregnant women. Dr. Holick co-authored studies showing that women with D deficiency are more likely to develop preeclampsia (J. Clin. Endocrinol. Metab., Sept. 2007) and to require Csections (J. Clin. Endocrinol. Metab., Mar. 2009).

Now let’s linger for just a moment over the very bottom of the list of vitamin D-rich foods at the bottom of the facing page. Well, not at the very bottom—it’s still a relatively unusual kid who jumps at the opportunity for tofu. We mean that short list of things “fortified with vitamin D:” milk, OJ, and cereal.

Guess why manufacturers started adding vitamin D to these and some other consumables? To make sure that kids got enough vitamin D in their diets. When milk in particular began to be fortified with vitamin D in the 1930s, the number of cases of rickets in children dropped off precipitously.

Now when most of us think of rickets, we imagine creaky 19th-century tenement buildings in New York City whose only windows faced out onto dank brick walls. And indeed, many of New York’s tenement-dwelling kids did get rickets in the early part of the 20th century because of diminished exposure to sunlight.

Unfortunately, while building codes may have improved somewhat over the past 100 or so years, kids these days are just about as sun-starved as ever. But now the causes are computers, video-game consoles, changes in diet, and sunscreen.

Maybe you’re wondering: what exactly is a ricket? Rickets is a condition that results in the softening of children’s bones, and can lead to deformities. As you might have guessed, it’s primarily caused by a deficiency in vitamin D. And the name does indeed call to mind other illnesses that we may consider long extinct in developed parts of the world: scurvy, TB, polio. It has unfortunately remained prevalent in places where malnutrition is a problem for kids. But it’s making something of a comeback in even the wealthiest nations, as reported in the journal Pediatrics (Aug. 1, 2008).

Indeed, a different study published in the same journal noted that “7.6 million US children and adolescents”—that represents 9 percent of the total pediatric population— were deficient in vitamin D, and “61%, representing 50.8 million US children and adolescents” had insufficient levels of the vitamin. Sixty-one percent!

It should be noted that these numbers in part reflect new adjustments in the guidelines for what constitutes low levels of vitamin D in kids. Nonetheless: “Only 4%,” the researchers noted, “had taken 400 IU of vitamin D per day for the past 30 days” (Pediatrics, Aug. 3, 2009).

Now even though both of these studies acknowledged the growing crisis of low vitamin D levels in kids and adolescents, there is an important difference between their conclusions. The authors of the first were looking primarily at rickets as one major consequence of D deficiency, whereas the authors of the second were concerned primarily with heart problems.

And that is just it. Vitamin D affects not just bones. Not even just hearts, but every cell of our bodies. We may think that if a kid looks okay—no knock-knees or bone problems here!—then they are okay. Or that low levels of vitamin D in childhood aren’t really a big deal. But that is unfortunately far from the case. Not only do low levels of vitamin D lead to problems for growing kids and adolescents, but new research suggests that their low levels in childhood could lead to lifelong health problems.

We interviewed Michael Holick, M.D., Ph.D., Professor of Physiology and Biophysics at Boston University School of Medicine and Director of the Vitamin D, Skin and Bone Research Lab, and he shared some alarming information with us. As just one example, he told us that vitamin D deficient kids have an almost 2.4-fold increased risk of developing type 1 diabetes. He compared that to the findings of a Finnish study that followed for 31 years children given 2,000 IU of vitamin D daily in the 1960s (Lancet, Nov. 2001). Their risk of developing type 1 diabetes dropped by 78 percent.

He also told us: “If you were born above Atlanta, GA, and lived there for the first 10 years of your life, you have 100 percent increased risk of developing multiple sclerosis for the rest of your life, no matter where you live.” Now, those are scary figures, and we should point out that those risks are still quite small. But one thing is for sure: vitamin D insufficiency in childhood can lead to all kinds of serious health consequences later in life.

Is It Possible to Get Too Much Vitamin D?

How Much is Too Much?

The following is a list of symptoms that may accompany a toxic level of vitamin D:*

  • Nausea and vomiting
  • Lack of appetite
  • Confusion
  • Weakness
  • Constipation
  • Irregular heart rhythm
  • Kidney stones

*This list was adapted from the website of the Mayo Clinic: www.mayoclinic.com.

Reader Reactions to Large Doses of Vitamin D

Some readers of our website have shared their experiences of taking vitamin D. While these responses may not be typical, and while we don’t have access to their test results to know if their blood levels are too high, these are the kinds of reactions we would advise you to talk to a physician about:

“I was prescribed 50,000 IU of vitamin D for six weeks, and it brought my blood levels up 19 points, into a safe range. But I also awoke each night drenched in sweat. It felt like hot flashes, but I’m too young for menopause. Finally, they went away, but for awhile they happened every night.”

“50,000 IU made me feel sick for days after I took it. I’ve managed to get my numbers up from 11 to 30 by sitting in the sun a few times a week, so now I try to do that instead.”

“I was taking 2000 IU of D3, which is derived from sheep’s wool. I’m allergic to wool, and it made me itch like crazy!”

This last problem seems like a pretty quick fix: switch to D2!

Now that we’ve piled on the information about how many kids and adults are low in vitamin D or downright deficient, along with the scary statistics about what is it stake, we’d like to talk in a little more detail about supplementing your vitamin D intake. We want to talk specifically about how much you should take, if it’s possible to take too much vitamin D, and what might happen to you in the event of an overload.

How Much Vitamin D Should You Take?

We’ve already touched a bit on the topic of supplementation, and there is no general consensus on how much you may need to take. That is partly because the number of IU will vary significantly based on how much you weigh, where you live and how much sun you get, and the pigmentation of your skin. It also depends upon how low your D is to begin with.

Two vitamin D experts we consulted on this subject had two slightly different sets of guidelines for determining about how many IUs of vitamin D the average person should take.

Dr. Michael Holick told us that as a general rule of thumb, each 100 IU of vitamin D per day adds about 1 ng per ml of blood. So if you need to raise your levels by 30 or so points, that would mean about 3,000 IU daily.

Dr. James Dowd gave us a slightly different metric. He said that those who are at a very high risk for vitamin D deficiency should think about adding roughly 25 IU of vitamin D per pound of their body weight; people who are simply at a moderate risk should add about 20 IU per pound.

Of course you should consult your doctor before making any major changes to your health regimen, and also to get a test of your vitamin D blood levels. If you’re deficient (i.e. with a 25 hydroxy vitamin D test score of 20 ng per ml of blood or below), you may very well need to start out on quite a high dose: 50,000 IU per week is fairly typical.

Can You Overdose on D?

While it is possible to overdose on vitamin D (more on that below), we have been assured by Dr. Holick and others that it is really pretty difficult to do so unintentionally.

According to Dr. Holick, a person would probably have to take in the neighborhood of 30,000 IU each day for anywhere from six months to a year before his vitamin D blood levels were likely to tip into the potentially toxic range.

But vitamin D toxicity is possible, and it’s quite serious. We don’t recommend that anyone take more than roughly 2,000 IU per day without careful supervision by a doctor. Some people may require more—pregnant women, for example— but those assessments should be made under your physician’s guidance.

Vitamin D Toxicity

It is probably impossible to get too much vitamin D from your diet, and Dr. Holick assures us that the body is also incapable of getting too much vitamin D from sun exposure: the body’s regulatory systems prevent that from happening.

Probably the only way to get too much vitamin D in your system is by overdoing it on supplements. People with certain health conditions, especially liver or kidney diseases, may be at a slightly increased risk for reaching toxic D levels.

What happens when the body is overloaded with vitamin D is actually that there is a buildup of calcium in your blood. Some of the symptoms that may occur include nausea and vomiting, weakness, confusion, a loss of appetite, constipation, and perhaps more seriously, heart rhythm abnormalities and kidney stones (see left sidebar). If you are experiencing any of these symptoms, see your doctor right away.

Fortunately, vitamin D toxicity is quite treatable under a doctor’s care. In some rare cases, patients may need to be hospitalized. But frequently, doctors can treat vitamin D toxicity by stopping a person’s vitamin D supplementation, restricting their calcium intake, hydrating their patients, or prescribing other drugs.

Success Stories

Vitamin D and Mental Health

There has been some research done on the connection between vitamin D and depression, as the symptoms for both can be similar.

So far, the results have been fairly mixed. One study in Japan did not show a statistically significant correlation between higher blood levels of vitamin D and decreased symptoms of depression (European Journal of Clinical Nutrition, Dec. 2009). However, a smaller study seemed to indicate that supplementation with vitamin D3 during the winter months helped reduce depressive symptoms in women (Applied Nursing Research, Aug. 2009). Clearly, more research is needed.

There has also been some recent research that aims to see whether or not there is a link between maternal or infant vitamin D deficiency and the onset of complex conditions such as schizophrenia and autism. But this research is highly controversial and no conclusive answers have been drawn at this stage.

A Real Pain in the Leg

“I had severe leg pain during the night and day for about four months.

“My doctor did blood work and found that my vitamin D level was 8.

“She prescribed me 50,000 IUs per week for twelve weeks and now my leg pain is almost nonexistent.”

And now time for some good news. Having vitamin D levels that are too low can be quite dangerous for your health. It can make you feel pretty awful, too.

One wonderful thing, then, about increasing your vitamin D intake is that it is likely to make you feel better in a number of ways, some of them unexpected.

For instance, we heard from one reader who began taking 2,000 IU of vitamin D every day in the winter not because she was deficient, but simply because she wasn’t getting any sun. She didn’t notice a big change at first, although she did report just generally better, mentally and physically, than she typically did during the long, cold months.

But then one day she discovered something unusual: a small patch of eczema that had plagued her for years, always in the same spot, had simply disappeared. This quarter-sized spot of scaly skin had been there for so long that she had stopped noticing it. Sometimes it would get a little better in the summer, but it never actually went away. She had a whole battery of dermatologist-prescribed lotions and creams for trying to deal with it, and with another few small areas that would intermittently bother her.

And then, a couple of months into her new vitamin D regimen, right smack-dab in the middle of the coldest, driest, most dreadful winter she could remember (her eczema typically flared up worst during the winter), she had a realization: the patch was gone! Without the help of lotions or creams, and without any other major changes to her diet or lifestyle.

We don’t know if the vitamin D cured her eczema, and as far as we know, there haven’t been any studies on oral vitamin D supplementation and atopic dermatitis. There has been some success with topically applied vitamin D reported in the literature, though (Journal of Dermatology, May 2005), and one of the more common treatments that dermatologists rely on for stubborn eczema is light therapy, which would boost vitamin D production.

But for those whose eczema isn’t severe, it certainly couldn’t hurt to at least give vitamin D supplementation a try. And if it helps your skin, which is your biggest organ, think of some of the unseen benefits it could be having for other cells and systems in your body.

Other noticeable results that some of our readers have reported after increasing their vitamin D intake include diminished joint pain, and fewer infections and colds.

Goodbye, Joint Pain

Below are some of the stories we’ve collected from readers on how taking more vitamin D has helped stave off joint pain:

“A couple weeks ago, my husband saw his endocrinologist and the doctor ordered a test of his vitamin D level. It was very low, so my husband was put on 2000 units per day.

“My husband had been having a lot of pain in his shoulder with a limited range of motion. An orthopedic surgeon told him that he had a tear in his rotator cuff, and that the only option was surgery.

“In less than a week and a half on the vitamin D supplement, he has NO pain and FULL range of motion. This is like a miracle! I think we need a second opinion on that surgery.”

Another reader reported the following:

“For several years I suffered from sore hips, knees and BODY! I chalked it up to getting older and going through perimenopause. On my last trip to the doctor, I told her I was only 48 years old and felt like I was 100. She tested my vitamin D and the count was 11. She prescribed 50,000 units once a week of Vitamin D.

“I took one dose and felt like a new person the next day! For the first time in years, I have NO soreness ANYWHERE!”

Cold Cure

We’ve also heard from readers who have said vitamin D has helped them have fewer colds:

“I used to catch lots of colds every year. When I was tested for vitamin D a few years ago, it was really low. I took a lot of vitamin D to get into the normal range.

“Since then I’ve had only two colds, each three days long. Vitamin D made a huge difference in my immune system.”

Vitamin D is very important for the immune system. It helps regulate T cells, and it also activates the gene that produces cathelicidin, a natural antimicrobial compound that fights infection (Future Microbiology, Nov. 2009).


The pervasiveness of vitamin D deficiency and insufficiency in adults and children is only just beginning to be uncovered.

At the same time, scientists are starting to shed light on how critical vitamin D is for every cell in the body. Sub-optimal levels of vitamin D have been linked to everything from an increased risk of heart disease and diabetes to joint pain and fatigue, among other problems; perhaps even dementia (Neurology, Jan. 2010).

Conversely, boosting vitamin D levels appears to help prevent everything from heart attack and stroke to many kinds of cancer, infections, kidney disease, hypertension, and other life-threatening conditions. In other words, getting more vitamin D might help save your life.

The ABC’s of Boosting Your D Levels

More Reading on Vitamin D

If you’re interested in reading more about vitamin D, experts Dr. James Dowd and Dr. Michael Holick have both written books on the subject.

Dr. Dowd’s is titled The Vitamin D Cure (Wiley, 2008), and Dr. Holick’s most recent is called The Vitamin D Solution (Hudson Street Press, 2010).

They also both have websites. Dr. Dowd’s is www.thevitamindcure.com, and Dr. Holick’s is www.uvadvantage.org. You might also be interested in an e-newsletter from the Vitamin D Council. Visit www.vitamindcouncil.org to subscribe.

Podcasts & CDs

For those who would like additional information on vitamin D deficiency, we have done a number of radio shows with national experts on the subject.

They are available for purchase at our website in CD or mp3 form. Visit www.peoplespharmacy.com, and search under “Radio Shows” for:

  • Vitamin D Update (749)
  • Health News Update (747)
  • Vitamin D (672)

Ask your doctor for a 25 hydroxy vitamin D test

This is the blood test that will determine your vitamin D blood levels. A reading of less than 20 nanograms (ng) per milliliter (ml) of blood is too low. A normal range is somewhere between 30 and 50, or as high as 80.

Consider monitoring your blood levels with a home test kit

If your 25 hydroxy vitamin D showed that your blood levels were too low, you should check back in regularly with your doctor for future testing. But if your levels were simply sub-optimal and you would like to keep an eye on your progress, there are now vitamin D test kits available for home use.

In the spring and summer, boost your vitamin D naturally with more sun

Adequate sun protection is vital for skin cancer prevention. But the experts we’ve consulted suggest that for individuals not at a high risk of skin cancer, getting 10–15 minutes of sun a few times a week is a good way to boost your D levels without increasing your cancer risk. (People with darker skin may need to spend slightly longer outside.) Then use sunscreen for any additional exposure.

During the winter months, supplement with extra vitamin D

Doctors may prescribe as much as 50,000 IU per week for those diagnosed as vitamin D deficient. For the rest of us, 1,000 to 2,000 IU daily is probably a reasonable amount. Other factors (weight, gender, skin color, if you’re pregnant or breastfeeding) may mean you should take a bit more or less. Talk to your doctor.

Add some vitamin-D rich foods to your diet

A balanced, well-rounded diet rich in vegetables, fruits, and sources of antioxidants and omega fats is essential. Some foods that are part of a healthy diet are also good sources of vitamin D, like fatty fish or some types of tofu.

Pregnant women should get extra vitamin D

New research shows that many pregnant women are vitamin D deficient. Vitamin D deficiency may lead to complications with pregnancy, and good vitamin D levels are also crucial to the health of the mother and child, including in later life.

Make sure that your child is getting enough D

Vitamin D is vital not only in infancy but throughout childhood and adolescence. New research suggests that children whose vitamin D levels are too low may be at risk for developing serious health problems as adults. The recommended dose for children is around 400 IU per day.

Look out for symptoms of a vitamin D overdose

Vitamin D toxicity is very rare. But if you’re on a high dose of D and experiencing any unusual symptoms, like nausea and vomiting, weakness, confusion, or loss of appetite, check with your doctor immediately.

Publication Information

Published on: March 11, 2024


Last Updated: July 09, 2024

Publisher: The People's Pharmacy

© 2024 The People's Pharmacy

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