Vitamin D deficiency

 

What are the risks of vitamin D deficiency? Answers from Katherine Zeratsky, R.D., L.D. Vitamin D deficiency — when the level of vitamin D in your body is too low — can cause your bones to become thin, brittle or misshapen. Vitamin D also appears to play a role in insulin resistance, high blood pressure and immune function — and how this relates to heart disease and cancer — but this is still being investigated. Although the amount of vitamin D adults get from their diets is often less than what's recommended, exposure to sunlight can make up for the difference. For most adults, vitamin D deficiency is not a concern. However, some groups — particularly people who are obese, who have dark skin and who are older than age 65 — may have lower levels of vitamin D due to their diets, little sun exposure or other factors. The Recommended Dietary Allowance (RDA) for adults is 600 international units (IU) of vitamin D a day. That goes up to 800 IU a day for those older than age 70. To meet this level, choose foods that are rich in vitamin D. For example, choose fortified foods, such as milk and yogurt, and fatty fish, such as salmon, trout, tuna and halibut. Don't overdo it, though. Very high levels of vitamin D have not been shown to provide greater benefits. In fact, too much vitamin D has been linked to other health problems. If you're concerned about whether you're getting enough vitamin D, talk to your doctor about your diet and whether a vitamin supplement might benefit you. June 05, 2015 References See more Expert Answers source: mayoclinic.org

Vitamin D

 

The truth about Vit D

Breathe easier: Get your vitamin D

 

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A new study finds asthmatics with Vitamin D deficiency are 25 percent more likely to experience acute attacks.

Asthma, which inflames and narrows the airways, has become more common in recent years. While there is no known cure, asthma can be managed with medication and by avoiding allergens and other triggers. A new study by a Tel Aviv University researcher points to a convenient, free way to manage acute asthmatic episodes -- catching some rays outside.

According to a paper recently published in the journal Allergy, measuring and, if need be, boosting Vitamin D levels could help manage asthma attacks. The research, conducted by Dr. Ronit Confino-Cohen of TAU's Sackler Faculty of Medicine, Meir Medical Center, and the Clalit Research Institute, and Dr. Becca Feldman of the Clalit Research Institute drew on the records of millions of patients and used physician diagnoses, rather than self-reports, for evidence of asthma episodes.

"Vitamin D has significant immunomodulatory effects and, as such, was believed to have an effect on asthma -- an immunologically mediated disease," said Dr. Confino-Cohen. "But most of the existing data regarding Vitamin D and asthma came from the pediatric population and was inconsistent. Our present study is unique because the study population of young adults is very large and 'uncontaminated' by other diseases."

A broad study

Dr. Confino-Cohen and her team of researchers analyzed the medical records of nearly four million members of Clalit Health Services, Israel's largest health care provider. The Vitamin D levels of 307,900 people were measured between 2008 and 2012. Researchers also took into account key predictors of asthma, such as obesity, smoking, and other chronic diseases. Of some 21,000 asthma patients in Israel studied, those with a Vitamin D deficiency were 25 percent more likely than other asthmatics to have had at least one flare-up in the recent past.

The researchers found that Vitamin D-deficient asthmatics were at a higher risk of an asthma attack. "Uncontrolled asthma" was defined as being prescribed at least five rescue inhalers, one prescription of oral corticosteroids, or visiting the doctor for asthma at least four times in a single year.

"Our results add more evidence to the link between Vitamin D and asthma, suggesting beneficial effects of Vitamin D on asthma exacerbations," said Dr. Confino-Cohen. "We expect that further prospective studies will support our results. In the meantime, our results support a recommendation for screening of Vitamin D levels in the subgroup of asthma patients who experience recurrent exacerbations. In those with Vitamin D deficiency, supplementation may be necessary."

Sunny side up?

While most of the Vitamin D in people's bodies comes from exposure to the sun, dermatologists recommend obtaining the ingredient from other sources -- fish, eggs, cod liver oil, fortified milk, or a dietary supplement -- due to the dangers of overexposure to the sun.

"We know a lot about this disease and many therapeutic options are available. So it's quite frustrating that the prevalence of asthma is not decreasing and many patients suffer exacerbations and significant impairment in their quality of life," Dr. Confino-Cohen, an allergy and clinical immunology specialist, said. "Increasing Vitamin D levels is something we can easily do to improve patients' quality of life."

Based on the findings, the researchers recommend that people whose asthma cannot be controlled with existing treatments have their Vitamin D levels tested. For those with a vitamin D deficiency, supplements may make sense.

"This study provided an exceptional opportunity to research asthma. I received a research grant from Clalit Health Services, which provided us with the opportunity to use their very large database and to conduct the study with the professional staff of Clalit Research Institute," said Dr. Confino-Cohen. "We anticipate further prospective research that will support our findings and open a new treatment modality to the population of uncontrolled asthmatics."

Finally: Missing link between vitamin D, prostate cancer

 

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A University of Colorado Cancer Center study recently published in the journal Prostate offers compelling evidence that inflammation may be the link between Vitamin D and prostate cancer. Specifically, the study shows that the gene GDF-15, known to be upregulated by Vitamin D, is notably absent in samples of human prostate cancer driven by inflammation.

"When you take Vitamin D and put it on prostate cancer cells, it inhibits their growth. But it hasn't been proven as an anti-cancer agent. We wanted to understand what genes Vitamin D is turning on or off in prostate cancer to offer new targets," says James R. Lambert, PhD, investigator at the CU Cancer Center and associate research professor in the CU School of Medicine Department of Pathology.

Since demonstrating that Vitamin D upregulates the expression of GDF-15, Lambert and colleagues, including Scott Lucia, MD, wondered if this gene might be a mechanism through which Vitamin D works in prostate cancer. Initially it seemed as if the answer was no.

"We thought there might be high levels of GDF-15 in normal tissue and low levels in prostate cancer, but we found that in a large cohort of human prostate tissue samples, expression of GDF-15 did not track with either normal or cancerous prostate tissue," Lambert says.

But then the team noticed an interesting pattern: GDF-15 was uniformly low in samples of prostate tissue that contained inflammation.

"Inflammation is thought to drive many cancers including prostate, gastric and colon. Therefore, GDF-15 may be a good thing in keeping prostate tissue healthy -- it suppresses inflammation, which is a bad actor potentially driving prostate cancer," Lambert says.

The study used a sophisticated computer algorithm to analyze immunohistochemical (IHC) data, a task that in previous studies had been done somewhat subjectively by pathologists. With this new technique, Lambert, Lucia and colleagues were able to quantify the expression of the GDF-15 protein and inflammatory cells by IHC staining on slides taken from these human prostate samples.

Additionally encouraging is that the gene GDF-15 was shown to suppress inflammation by inhibiting another target, NFkB. This target, NFkB, has been the focus of many previous studies in which it has been shown to promote inflammation and contribute to tumor formation and growth; however, researchers have previously been unable to drug NFkB to decrease its tumor-promoting behavior.

"There's been a lot of work on inhibiting NFkB," says Lambert. "Now from this starting point of Vitamin D in prostate cancer, we've come a long way toward understanding how we might use GDF-15 to target NFkB, which may have implications in cancer types far beyond prostate."

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Story Source:

The above story is based on materials provided by University of Colorado Denver. The original article was written by Garth Sundem. Note: Materials may be edited for content and length.

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Journal Reference:

1. James R. Lambert, Ramon J. Whitson, Kenneth A. Iczkowski, Francisco G. La Rosa, Maxwell L. Smith, R. Storey Wilson, Elizabeth E. Smith, Kathleen C. Torkko, Hamid H. Gari, M. Scott Lucia. Reduced expression of GDF-15 is associated with atrophic inflammatory lesions of the prostate. The Prostate, 2014; DOI: 10.1002/pros.22911

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Vitamin D and the nursing mother

 

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Everyone seems to agree that vitamin D is important throughout life. This is certainly as true in the first year of life as it is later on. For it is during the first year that, in addition to its role in calcium metabolism, this critical nutrient reduces both the risk of current infections and the late-life development of such autoimmune diseases as multiple sclerosis and type 1 diabetes.

Both the Institute of Medicine (IOM) and the American Academy of Pediatrics (AAP) agree that vitamin D intake during the first year of life should be 400 IU/d. My own estimation of the requirement (for different ages and body sizes) is 65-75 IU/kg body weight per day. For average body weights in infants during the first year of life that rule of thumb computes to somewhere between 300 and 500 IU/d for infants. So, while there is still contention with respect to the optimal intake for adults, there really is no disagreement about how much is needed for infants, either among various authoritative sources or arising from different approaches to the evidence. With respect to infants, 400 IU/d seems to be just about right.

The question is, how is the infant to get that vitamin D? Human milk, in most nursing mothers, contains very little vitamin D. Infant formulas, from various manufacturers, all contain some added vitamin D in amounts calculated to be sufficient to meet an infant's needs. But extensive studies during the first year of life reveal that less than one-fifth of all infants ever get as much as the recommended 400 IU/d from any source, and fewer than one out of 10 breast-fed infants meet the requirement. As a result, the AAP urges that all infants, regardless of whether they are breast or formula fed, receive their 400 IU/d as pediatric drops. Unfortunately, this recommendation, while appropriate, is not often followed. Most babies are just not getting the vitamin D they need. The late-life consequences of this shortfall could be enormous.

It must seem strange that on the one hand we stress that human milk is the best source of nourishment for our babies, and on the other seem to ignore the fact that human milk doesn't contain the vitamin D those babies need. The explanation, very simply, is that the disconnect is artificial. Nursing mothers have so little vitamin D in their own bodies that there is little or none left over to put into their milk. But it has not always been this way. We know that the vitamin D blood concentrations that are regularly found today in Africans living ancestral lifestyles are high enough to support putting into breast milk all the vitamin D an infant needs. But the bulk of the world's population today is not living on the high equatorial plains of East Africa nor exposing much of its skin for most of the day.

Fortunately, we don't have to return to East Africa. It turns out that, if we give nursing mothers enough vitamin D to bring their blood levels up to the likely ancestral levels, then they automatically put all of the vitamin D their baby needs into their own milk, thereby ensuring that the infant gets total nutrition without the need to resort to vitamin D drops.

How much vitamin D does the mother need so as to ensure an adequate amount in her milk? As with everything else related to vitamin D, there is a lot of individual variation, but it appears that the daily intake must be in the range of 5,000-6,000 IUs. As no surprise, that's just about the amount needed to reproduce the vitamin D blood levels in persons living ancestral lifestyles today. And while 5,000-6,000 IU may initially seem high, it is important to remember how much the sun produces for us. A single 15 minute whole body exposure to sun at mid-day in summer produces well over 10,000 IU.

There is one important proviso for nursing mothers concerning the needed intake. Those who live in North America and have to rely on supplements should be certain that they take their supplements every day. While for other purposes it is possible to take vitamin D intermittently (e.g., once a week), that doesn't work for putting vitamin D into human milk. The residence time of vitamin D in the blood is so short that, if the mother stops taking her vitamin D supplement for a day or two, vitamin D in her milk will be low (or absent altogether) on the days she skips.

There is a glaring disconnect here between these well-attested physiological facts and the official IOM recommendation for nursing mothers, i.e., only 400 IU/d -- the same intake for her as IOM recommends for her baby (whose body weight is less than 10% of her own). The IOM, if it were to be explicit about its current recommendations, would be telling nursing mothers something like this:

"The evidence we analyzed indicates that your own body needs only 400 IU of vitamin D each day. Unfortunately, that won't allow you to put any vitamin D into your breast milk. Sorry about that . . . So, if you want to ensure that your baby is adequately nourished, you are going to have to resort to giving your infant vitamin D drops."

That would be a hard message to sell, and clearly, it makes little sense on its face. As I have already noted, women living ancestral lifestyles (whether or not they are nursing an infant) have far higher blood levels of vitamin D than contemporary urban Americans. Milk production (and its optimal composition) are simply two of the many functions that vitamin D supports in a healthy adult. This breast-feeding example is not a special case; it is just one of the many pieces of evidence that point to the fact that current vitamin D recommendations for adults are too low -- way too low.

Vitamin D supplements -- and in this case vitamin D drops -- are literal lifesavers for infants today. But what about two or three generations back -- before nutritional supplements come into existence, but long after migration out of Africa? Ninety years ago vitamin D had not yet been discovered, and there certainly were no vitamin D supplements that could have been used. How did we get by through those thousands of years? There are two answers. Most of us, living in temperate latitudes, got a lot more sun exposure than we do today, and of course there were no sunscreens, so there was no blocking of the solar radiation that produces vitamin D in our skin. Those of us living in far northern latitudes survived mostly by depending upon diets that were very high in seafood, which is naturally a rich source of vitamin D. And those of us who got vitamin D by neither route were at increased risk of a whole host of vitamin D-related disorders, most obvious and most easily recognized being rickets.

The bony deformities of rickets were common a century ago in Europe, North America, and East Asia, and were largely eradicated in growing children by use of cod liver oil and, in the US, by the introduction of vitamin D fortification of milk in the 1930s. Fortunately, growing children can repair some of the bone deformities of rickets if they are given vitamin D soon enough. But, repairing rickets, while a good and necessary thing to do, is not sufficient. It is too late, by the time we recognize the deformities of rickets, to ensure maximal protection against the autoimmune diseases (for example), for which susceptibility is mainly determined in the first year of life.

To sum up, we now better recognize the importance of vitamin D in the earliest stages of life. Furthermore, there is, as noted earlier, quite good agreement on how much an infant needs. Where we lack consensus is how to make certain that all of our babies get the amount they need. Why not rely on giving nursing infants vitamin D drops, as the AAP recommends? Two reasons: 1) It's been tried and has failed; and, 2) When it does work in individual infants, it provides no benefit for the mother. By contrast, ensuring an adequate vitamin D input to the mother during pregnancy and lactation is almost certainly the best way to meet the needs of both individuals.

An "adequate" intake for nursing mothers, as noted earlier, is not the 400 IU/d the IOM recommends, but is instead in the range of 5,000-6,000 IU/d, taken daily. If they get that much, they will meet not only their own needs, but their infant's as well. And they will have the satisfaction of knowing that they are supplying all their baby's needs, the natural way.