Vitamin D
recommended daily dosage
The recommended daily intake of vitamin D is
200 iu to 400 units for adults younger than 50 years and 600 iu to 800 units for those older than 70
years. Vitamin D supplementation is especially important in elderly persons
because skin synthesis and absorption of vitamin D may be impaired. As time goes
on, the scientific community is recognizing that perhaps higher doses of vitamin
D intake may be appropriate, but more time is needed to determine whether higher
intakes through supplements is safe.
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Dry Vitamin D, 400 IU supplement
Vitamin D Dietary
Supplement
Helps Maintain Normal Bone and Tooth Formation
Vitamin D
supplement helps
the body to regulate the transport of calcium from the digestive system
through the bloodstream to bone. It also assists in the retention of
calcium and phosphorus. Nature's Way Vitamin D is 100% natural cholecalciferol. The dry form is specially formulated for easy
absorption. It contains no artificial ingredients or preservatives.
To buy this product or to sign up to a FREE newsletter, see
Vitamin D supplement sale
Supplement Facts:
Amount Per 1 capsule:
Vitamin D - 400 IU - 100%DV (as cholecalciferol)
Vitamin D benefit
The best known vitamin D benefit is in keeping bones and teeth strong and
healthy. Vitamin D helps regulate the growth and activity of cells and it
reduces inflammation.
People with higher levels of vitamin D are less likely to suffer autoimmune
diseases, including type 1 diabetes and
multiple sclerosis.
They may even have less heart disease and better lung function. Vitamin D does
far more than aid calcium absorption. Vitamin D has a benefit on the immune
system — which explains its effect on autoimmune diseases. Biochemical studies
suggest that it helps keep cells from becoming malignant — and when cells do go
bad, it encourages them to self-destruct. Scientists suspect the vitamin has
still other functions. Tissues throughout the body have receptors for vitamin D.
Vitamin D has other benefits: It reduces the risk for of
chronic diseases, including type 2 diabetes, heart disease, osteoporosis,
and probably cancers such as breast cancer, colon cancer, and ovarian
cancer.
Seniors and Vitamin D supplement
Older Americans need more vitamin D to help strengthen bones than
what current guidelines recommend. Men and women age 50 and older should take
about 600 to 800 international units of vitamin D each day - more than the 400
to 600 daily units the Institute of Medicine recommends, the American Medical
Women's Association has said. Sunscreen, protective clothing and time spent
indoors already keep most older Americans from getting enough vitamin D from
exposure to sunlight's ultraviolet-B rays.
Vitamin D supplement and Teenage Girls
Many adolescent girls have low vitamin D levels, especially non-white
girls. Reduced sunshine exposure is probably more of a factor than dietary
intake. Vitamin D deficiency during childhood and adolescence might impair the
acquisition of peak bone mass at the end of skeletal growth and maturation,
thereby increasing the risk of osteoporotic fracture later in life. A vitamin D
supplement could be of benefit.
Osteoporosis and Vitamin D deficiency
Vitamin D deficiency is quite common in cases of hip
fractures. A look-back study of 548 patients older than 60 years of age who were
admitted at South Glasgow University Hospital in Scotland in the previous 4
years, showed that 97 percent of the patients had vitamin D levels below normal.
Dr. Stephen Gallacher, lead researcher and consultant endocrinologist at the
hospital said: ''Although the numbers were too small to justify extensive
subgroup analyses the study appears to demonstrate that vitamin D inadequacy
represents a significant correctable risk factor for fragility fracture and
perhaps specifically for the hip."
Older men and women who fail to get enough vitamin D -- either from
their diets or exposure to the sun -- are at heightened risk for muscle weakness
and poor physical performance. This is troubling given the high numbers of older
folks who are deficient in vitamin D. However, even good sun exposure does not
guarantee adequate blood levels of vitamin D. In many individuals, vitamin D
level can remain low despite abundant exposure to sunlight.
Dr. Sahelian comments: Most elderly patients have a vitamin D
deficiency due to lack of adequate sun exposure, particularly in cold climates with long
winters. And there could be a deficiency even with many hours of sun exposure a
week. Vitamin D can be supplemented by taking a
multivitamin and
mineral
complex, or through cod liver oil. A dosage of 400 to 800 units should be
adequate. Sitting by the window or taking walks outside could be helpful.
Osteoporosis risk can
be reduced. Low vitamin D status is defined as 25-hydroxyvitamin D
concentrations below 30 ng/mL
Deficiency
As little as 100 IU vitamin D2 is effective in the prevention of rickets.
Vitamin D deficiency results in lowered absorption of calcium and phosphorous.
Prolonged vitamin D deficiency has a negative impact on bone mineralization.
Vitamin D deficiency leads to several bone diseases including:
Rickets: a
childhood disease characterized by failure of growth and deformity of long
bones. Osteoporosis; and Osteomalacia: a bone-thinning disorder in adults that
is characterized by proximal muscle weakness and bone fragility. Osteomalacia
can only occur in a mature skeleton.
Rickets appears to be the tip of the vitamin D deficiency iceberg.
There is evidence that vitamin D deficiency is still common in children and
adults even though certain foods have been fortified with the vitamin. In utero
and during childhood, vitamin D deficiency can cause growth retardation and
skeletal deformities and may increase the risk of hip fracture later in life.
Vitamin D deficiency in adults can precipitate or exacerbate osteopenia and
osteoporosis, cause osteomalacia and muscle weakness, and increase the risk for
certain cancers.
Children with inflammatory bowel disease have a high prevalence of
vitamin D deficiency.
In all regions of the world, more than half of
postmenopausal women with the crippling bone disease osteoporosis are vitamin D
deficient.
Soft drink, juice and iced tea intake are related to a greater risk of
vitamin D deficiency. On the other hand, adolescents who drink milk
and eat cereal are less likely to be deficient on the vitamin.
About a quarter of Britons suffer from a winter deficiency of vitamin
D, which can increase the risk of muscle weakness, autoimmune diseases,
osteoporosis and certain types of cancer. Britain's northern location and lack
of sunshine means that during the winter months many people do not get enough
vitamin D, which the body makes when it is exposed to sunlight. Foods such as
oily fish and egg yoke are rich in vitamin D and breakfast cereals and margarine
are fortified with it, but it might not be enough to get Britons through the
winter months when their stores of vitamin D diminish.
Adolescents and teenagers
Vitamin D deficiency may be a common but
unrecognized problem among U.S. adolescents. Researchers found that among 11- to
18-year-olds living in Boston, nearly one-quarter were deficient in vitamin D, a
nutrient that aids in calcium absorption and is vital for healthy bone
development. The problem is preventable with an adequate diet and time outdoors. The
body naturally synthesizes vitamin D when the skin is exposed to the sun, and
milk and certain other foods, including many breakfast cereals, are fortified
with the vitamin. But U.S. children increasingly fill up on soft drinks at the
expense of milk, and spend more time in front of the TV or computer than
outdoors.
Blood levels and testing
Some scientists believe that optimal serum 25-hydroxyvitamin D
[25(OH)D] level should be greater than 80 nmol/L.
Another measurement is serum hydroxyvitamin D level of 40 to 60 ng/ml. In older adults, a serum 25-hydroxyvitamin D concentration greater than 70 nmol/L
lowers the risk of fracture. However, I am still not convinced that we know the
ideal dosage to supplement with based on blood test results.
Do you recommend people being tested for vitamin D
levels before taking a supplement?
Unless a person has an unusual diet or a chronic health condition
that could lead to severe vitamin D deficiency, I don't think testing is
necessary. There are hundreds of blood tests available to check levels
of different vitamins, minerals, amino acids, hormones, cholesterol,
various lipids, inflammation markers, liver studies, kidney studies,
etc., etc.. At some point one has to balance the costs and inconvenience
of testing versus the potential benefits they provide. Unless a person
has an unusual medical condition or diet where blood vitamin D levels
are suspected to be too low or too high, blood testing does not give us
much of a clue on exactly how much to supplement. I am cost conscious
and practical in my approach. I think in this country we are going
overboard in terms of testing, and for the amount of money we spend on
diagnostic testing and health care we are not even close to being one of
the healthiest nations on the planet. We do so many diagnostic tests in
this country without knowing whether people are actually healthier or
live longer as a result of the testing. The people who end up being
better off are doctors and the those who own the labs. I think the vast
majority of people who don't have an unusual diet or serious and chronic
medical condition just take 400 to 800 units a day they should be fine
and they don't have to worry about checking for vitamin D levels.
Side effects, caution, safety
High dosages of vitamin D may cause short term or long term side effects. Long
term vitamin D side effects in high dosages could include brain vessel
calcification and calcification of soft tissues. It is possible that taking high
dosages of vitamin D can reduce cancer incidence, but it could increase the
incidence of other medical conditions. Until more research is published
regarding the influence of high dose intake over a decade or more, I prefer
keeping dosages to below 1000 units a day unless a person has a severe
deficiency. We had
an email from someone who claims high dosages caused excitation
and excess energy and here are other emails we have received:
My personal effort to raise Vit D 25 OH with higher doses of Vit. D3 (upwards of 7000 IU) led to a strange elevation in blood pressure, from 115/70 to 180/90. I double checked. Now i take only 2000IU without elevation of blood pressure. This may only be a personal reaction, but worth consideration by your readers.
I am a medical student at UIC (University of Illinois) and I am studying for my board exam. These people who experience jitteryness and whole body anxiety are likely suffering from hypervitaminosis D. Although typically this takes months to develop, its symptoms include irritability. By inducing hypercalcemia they are also at risk for hypertension.
In your e-newsletter you printed an email from someone who had reacted to high dose vitamin D with anxiety. I believe she was taking 3,000 units daily. You asked if anyone else had these reactions. I am currently on 4,000 units daily, 5 days per week, plus a prescription dose of 50,000 units, 2 days per week. This is due to deficiency since I almost never go outside for any length of time due to allergy to stinging insects (I'd been stung 6 times in 3 years). Also, my doctor wants me to be at an optimal level, since I have 2 precancerous growths (stomach and right eye). There is a strong history of stomach cancer in my family. I started with a vitamin D level of 31. It is now up to 51, and the goal is 65. It has definitely increased my anxiety. I was already on Xanax for muscle spasms that kept me from walking, and have now had to increase the dosage for only the second time in 24 years of taking it. I already take a high dose of L-tryptophan. Nothing seems to help. Luckily, I am now at a high enough level of vit,. D that I should be cutting back soon. I had no trouble at all on 4,000 units daily.
Vitamin D and vascular calcification.
Curr Opin Lipidol. 2007 Feb; Zittermann A, Schleithoff SS, Koerfer R.
Department of Cardiothoracic Surgery, Northrhine Westfalia Heart Center, Ruhr
University Bochum, Bad Oeynhausen, Germany.
Vascular calcification is frequently found in patients with osteoporosis,
atherosclerosis and chronic kidney disease, leading to high morbidity and
mortality rates. The effects of vitamin D excess and deficiency on vascular
calcification are reviewed in this article. There is evidence from experimental
studies that mediacalcinosis induced by vitamin D excess is an active and
reversible process. Vitamin D excess, however, is rarely seen in the general
human population. Experimental data also demonstrate that physiologic vitamin D
actions include the inhibition of processes that are important for intimal and
medial artery calcification such as pro-inflammatory cytokine release, adhesion
molecule release, and proliferation and migration of vascular smooth muscle
cells. In uremic rats, low levels of the vitamin D hormone calcitriol are
associated with massive vascular and soft tissue calcifications. Whereas
retrospective studies already indicate a beneficial effect of active vitamin D
on mortality rates in chronic kidney disease, little is yet known about the
effect of vitamin D deficiency on cardiovascular morbidity and mortality in the
general population. Available data indicate that vitamin D exerts a biphasic
'dose response' curve on vascular calcification with deleterious consequences
not only of vitamin D excess but also of vitamin D deficiency.
Vitamin D in Food
Vitamin D is found in milk, yogurt and cheeses, as well as in some
fortified orange juice, fish, oysters, and certain fortified cereals.
People might want to consider a vitamin D supplement to raise their intake to 400
to 800 IUs per day, which is well within the safety guidelines established by
the National Academy of Sciences. Taking more vitamin D could be especially
important for people living in northern areas, which receive less vitamin D from
sunshine. African Americans, who don't produce as much vitamin D because of
their skin pigment, could also benefit significantly from a higher intake.
Breastfeeding and Vitamin D
Breastfed babies living in northern latitudes often lack healthy levels
of vitamin D, and may even be severely deficient. In northern latitudes, such as
that in Iowa (41 degrees North), sunshine is too diminished in the winter for
the infants to generate enough vitamin D on their own. Many infants are vitamin
D deficient during winter than during summer. The vitamin D deficiency is less
prevalent as babies get older. Many decades ago it was standard practice to give
infants a teaspoon of cod liver oil, which averages about 400 units of vitamin D
per day. When the use of baby formula became popular, enough vitamin D was added
to the formula to prevent deficiency. Then since the 1970s women returned to
breast feeding, but they did not think of giving their babies vitamin D
supplements. Breastfed infants require about 200 units of vitamin D per day. It
may be a good idea for women breastfeeding their infants to give them cod liver
oil supplements during the winter months. Pediatrics, August 2006.
Cancer Prevention
Cancer researchers are urging people to take a vitamin D supplement to lower
their risk of colon, pancreatic, prostate, breast and ovarian
cancer, saying studies
showed a clear link. A review of dozens of studies, including several large long-term
ones, on the relationship between vitamin D and certain types of cancer showed
vitamin D has the ability to reduce the incidence of certain cancers. Vitamin D
deficiency may account for several thousand premature deaths from colon, breast,
ovarian and other cancers annually.
Consumption of Vitamin D tablets was found to cut the risk of
pancreatic cancer by 40 percent, according to a study led by researchers at
Northwestern and Harvard universities. The findings point to Vitamin D's
potential to prevent the disease, and is one of the first known studies to use a
large-scale epidemiological survey to examine the relationship between the
nutrient and cancer of the pancreas. The study, led by Halcyon Skinner, Ph.D.,
of Northwestern, appears in the September, 2006 issue of Cancer Epidemiology
Biomarkers & Prevention. The study examined data from two large, long-term
health surveys and found that taking the U.S. Recommended Daily Allowance of
Vitamin D (400 IU/day) reduced the risk of pancreatic cancer by 43 percent. By
comparison, those who consumed less than 150 IUs per day experienced a 22
percent reduced risk of cancer. Increased consumption of the vitamin beyond 400
IUs per day resulted in no significant increased benefit.
Plenty of sunshine and vitamin D may
help people with early stage lung cancer survive longer after surgery. Patients
who have high levels of vitamin D and had lung cancer surgery in sunny months
are more than twice as likely to be alive five years after surgery compared to
patients with low levels of vitamin D who had surgery in the winter. Exposure to
sunshine is a significant source of vitamin D, which also comes from food and
dietary supplements.
Colon Cancer
When epidemiologists began mapping the incidence of
colon cancer in the
United States back in the 1970s, they noted a curious pattern. People in the
South were half as likely to die of colon cancer as those in the Northeast.
Could the reason be the sunshine vitamin D?
What's the right Vitamin D dose for cancer prevention?
There is some evidence that high levels of vitamin D may reduce colon cancer and
breast cancer and some researchers are suggesting people take up to 2,000
international units (IU) of vitamin D a day in a form called vitamin D3 (
cholecalciferol ). However, there could be a risk for vitamin D excess or
toxicity when these high dosages are taken for prolonged periods. The 2,000-IU
daily dose of vitamin D is considered the "tolerable upper limit" for vitamin D,
according to the National Academy of Sciences' Institute of Medicine (IOM).
Until we learn more about the side effects of vitamin D excess, I prefer users
not exceed 1,000 units of vitamin D a day.
Depression treatment
Vitamin D and depressive symptoms in women during the winter: a pilot study.
Appl Nurs Res. 2009 Aug;22(3):221-5. Shipowick CD, Moore CB, Corbett C,
Bindler R. Washington State University, Richland, WA 99352, USA.
Research indicates that vitamin D supplementation may decrease depressive
symptoms during the winter months. In this study, nine women with serum vitamin
D levels <40 ng/ml were administered the Beck Depression Inventory (BDI)-II.
After vitamin D3 supplementation, six of these women completed the BDI-II and
had their serum vitamin D levels reassessed. Vitamin D supplementation was
associated not only with an increase in the serum D levels by an average of 27
ng/ml but also with a decline in the BDI-II scores of an average of 10 points.
This study suggests that supplemental vitamin D3 reduces depressive symptoms.
Vitamin D and Pregnancy
The children of mothers who had low levels of vitamin D during their
pregnancy have reduced bone mineral content during childhood, potentially
increasing their risk of osteoporosis in later life.
High levels of vitamin D during pregnancy may lower the
risk of wheezing and asthma in offspring during early childhood. Vitamin D
deficiency and asthma are both common in the northeastern part of the United
States, suggesting that the two may be related. Moreover, while vitamin D has
important effects on the immune system, its affect on asthma is not known.
Researchers tracked 1,306 mother-child pairs for more than three years, and used
a food frequency questionnaire to assess levels of maternal vitamin D during
pregnancy. By age two, there was a clear association between increasing prenatal
levels of vitamin D in the mother and decreasing risk of wheezing or
doctor-diagnosed asthma in the child. The average total vitamin D intake during
pregnancy was 550 international units (IU) per day. In a more thorough analysis,
a 100-IU increase in maternal vitamin D intake was associated with an odds ratio
of 0.90 for "any wheeze" in the child -- defined as mother-reported wheeze
during the first two years of life. When the data were adjusted to account for
dietary levels of fruit, vegetables, and fish, the results did not change. A
preliminary look at the three-year data show a similar strong association
between higher maternal vitamin D levels and lower risk of wheezing and asthma
at age three years.
Vitamin D from Sun or Supplement Pill ?
Should you purposely tan for vitamin D? You can get all the vitamin D
with a vitamin supplement pill -- you do not have to put yourself at increased risk of skin
cancer and photoaging. The public is getting a mixed message on sun and health
because advocates of increased UV exposure, like the indoor tanning industry,
are advocating sunbathing as a means of getting more vitamin D for everyone,
including young light-skinned people who face the greatest skin cancer risk. New
research has indeed shown that some groups of people who may get little sun
exposure and don't drink much milk, for example frail elderly individuals at
risk of bone fractures, will benefit from getting more vitamin D than is
currently recommended by the US Department of Agriculture. There's also evidence
that people with very dark skin and those who live in northern climes may be
deficient in the vitamin. But such deficiencies can be handled with oral
supplementation. If you are worried that you're not getting enough vitamin D,
take a vitamin D supplement pill.
Vitamin D needed by Diabetics
A majority of patients with type 2 diabetes show signs of vitamin D
deficiency. Because a lack of vitamin D can negatively affect bone health and
have other adverse effects routine vitamin D supplementation with about 400
units a day should be considered for people with diabetes.
People with a low level of vitamin D in the blood have poorly functioning
insulin-producing cells and show a poor response to insulin, even when their
blood sugar levels are normal.
D2 or D3?
It appears that both forms of the vitamin are useful
Vitamin D2 Is as Effective as Vitamin D3 in Maintaining Circulating
Concentrations of 25-Hydroxyvitamin D.
J Clin Endocrinol Metab. 2008 March; Michael F. Holick, Rachael M. Biancuzzo,
Tai C. Chen, Ellen K. Klein, Azzie Young, Douglass Bibuld, Richard Reitz, Wael
Salameh, Allen Ameri, and Andrew D. Tannenbaum. Endocrine Section, Department of
Medicine, Boston University School of Medicine, Boston, Massachusetts 02118;
Two reports suggested that vitamin D2 is less effective than vitamin D3 in
maintaining vitamin D status. Our objective was to determine whether vitamin D2
was less effective than vitamin D3 in maintaining serum 25-hydroxyvitamin D
levels or increased the catabolism of 25-hydroxyvitamin D3. This was a
randomized, placebo-controlled, double-blinded study of healthy adults ages
18–84 yr who received placebo, 1000 IU vitamin D3, 1000 IU vitamin D2, or 500 IU
vitamin D2 plus 500 IU vitamin D3 daily for 11 wk at the end of the winter.
Sixty percent of the healthy adults were vitamin D deficient at the start of the
study. The circulating levels of 25-hydroxyvitamin D (mean ± sd) increased to
the same extent in the groups that received 1000 IU daily as vitamin D2. Our
results suggest a 1000 IU dose of vitamin D2 daily was as effective as 1000 IU
vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and did not
negatively influence serum 25-hydroxyvitamin D3 levels. Therefore, vitamin D2 is
equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status.
Vitamin D Research Update
Boston researchers report a link between low serum levels of vitamin D
and decreased knee function in patients with
osteoarthritis of the knee. At the
annual meeting of the American College of Rheumatology in San Antonio,
researchers presented findings from 221 subjects recruited from the Boston VA
Medical Center. All had knee arthritis and reported knee pain on most days in
the month before they joined the study. The investigators measured blood levels
of vitamin D at the start and again after 15 and 30 months. They compared change
in vitamin D levels with changes in knee pain, physical function and muscle
strength during the 30-month study period. Low levels were associated with
higher levels of pain and disability and to a lesser extent muscle weakness. The
researchers also found that about 50 percent of the population were deficient in
vitamin D.
People with higher blood levels of vitamin D may be less likely to develop gum disease. Using data from a national U.S. health survey, researchers found that teenagers and adults with the highest blood levels of vitamin D were 20 percent less likely than those with the lowest levels to show signs of gingivitis -- a milder form of gum disease in which the gums become swollen and bleed easily. The study can only show that there's an association between vitamin D status and gum health, and not that the vitamin is providing the benefit.
People on strict raw food vegetarian diets are thin but healthy. Although nutritionists and the food industry have warned that a diet without dairy foods can lead to the bone-thinning disease osteoporosis, a team at Washington University School of Medicine in St. Louis found the vegans they studied had many of the signs of strong bones. Raw food vegetarians believe in eating only plant-derived foods that have not been cooked, processed, or otherwise altered from their natural state. Researchers expected the vegans to have low vitamin D levels because they avoid dairy products, which are fortified with the vitamin. But in fact their vitamin D levels were "markedly higher" than average. Vitamin D is made by the skin when the body is exposed to sunlight and is key to keeping strong bones. And the vegans had low levels of C-reactive protein, an inflammatory molecule that is linked with the risk of heart disease, diabetes and other chronic disease. Furthermore, they had lower levels of IGF-1, a growth factor linked to risk of breast and prostate cancer.
People who try to stay bronze with the help of a tanning bed tend to have higher blood levels of vitamin D than those shun the salon. The study of 156 adults found those who regularly soaked up the artificial rays of a tanning bed had a 90 percent higher average vitamin D concentration in their blood. The tanners, who frequented the salon at least once a week for 6 or more months, also had greater bone density in the hips. The study, published in the American Journal of Clinical Nutrition, was partially financed by the UV Foundation, which is funded by the Indoor Tanning Association, an industry group. A precursor to vitamin D exists naturally in the skin, and exposure to the sun's ultraviolet (UV) rays touches off a chemical process that creates the usable form of the vitamin. Because vitamin D is needed for proper calcium absorption, the nutrient is vital to bone health. There is also a body of research suggesting vitamin D helps protect against certain cancers and some autoimmune diseases, such as type 1 diabetes and multiple sclerosis. But the fact that UV radiation is the major cause of skin cancer, as well as the major source of vitamin D, has made for a controversy over how much sun -- or artificial sun -- people should get.
Tanning is associated with optimal vitamin D status
(serum 25-hydroxyvitamin D concentration) and higher bone mineral density
American Journal of Clinical Nutrition, Vol. 80, No. 6, 1645-1649, December
2004
Background: Vitamin D is made in the skin on exposure to solar radiation, and
it is necessary to optimal skeletal health. Subjects who use a tanning bed that
emits ultraviolet B radiation (290–315 nm) are likely to have higher
25-hydroxyvitamin D [25(OH)D] concentrations than do subjects who do not
regularly use a tanning bed. Objective: The first objective of this study was to
ascertain whether subjects who regularly use a tanning bed have higher 25(OH)D
concentrations than do subjects who do not use a tanning bed. The second
objective was to ascertain whether higher 25(OH)D concentrations correlated
positively with bone mineral density. Design: This cross-sectional analysis
examined 50 subjects who used a tanning bed at least once a week and 106 control
subjects. Each subject gave a blood specimen for measurement of serum 25(OH)D
and parathyroid hormone concentrations. Each subject underwent bone mineral
density testing of the hip and spine. Results: Subjects who used a tanning bed
had serum 25(OH)D concentrations 90% higher than those of control subjects.
Subjects who used a tanning bed had parathyroid hormone concentrations 18% lower
than those of control subjects.
Tanners had significantly higher BMD and z scores at the total hip than did
nontanners. Conclusion: The regular use of a tanning bed that emits vitamin
D–producing ultraviolet radiation is associated with higher 25(OH)D
concentrations and thus may have a benefit for the skeleton.
Why the optimal requirement for Vitamin D(3) is probably much higher than
what is officially recommended for adults.
J Steroid Biochem Mol Biol. 2004 May;89-90:575-9.
The physiologic range for circulating 25-hydroxy-vitamin D3 [25(OH)D; the
measure of Vitamin D nutrient status] concentration in humans and other primates
extends to beyond 200nmol/L (>80ng/mL). This biologic "normal" value is greater
than current population norms for vitamin D. Concentrations of vitamin D that
correlate with desirable effects extend to at least 70nmol/L, with no obvious
threshold. Randomized clinical trials using 20mcg (800IU) per day of Vitamin D
show that this suppresses parathyroid hormone, preserves bone mineral density,
prevents fractures, lowers blood pressure and improves balance. Calcium
absorption from diet correlates with vitamin D in the normal range. Health
effects of Vitamin D beyond osteoporosis are mostly supported by the
circumstantial evidence of epidemiologic studies and laboratory research. These
include prevention of cancer and the autoimmune diseases, insulin-dependent
diabetes and multiple sclerosis. One mcg per day of Vitamin D(3) (cholecalciferol)
increases circulating vitamin D by about 1nmol/L (0.4ng/mL). A recommended
dietary allowance (RDA) is the long-term daily intake level that meets the total
requirements for the nutrient by nearly all healthy individuals (it would
presume no sunshine). If 70nmol/L is regarded as a minimum desirable target
vitamin D concentration, then current recommendations of 15mcg per day do not
meet the criterion of an RDA.
Vitamin D supplement use emails
Q. I am a vegetarian (not a vegan). Do you know of any
Vitamin D3 supplements (400 IU) which use only sheep's wool (lanolin) and not
any products that are derived by killing the source animal? One of Dr.
Sahelian's articles features a picture of Nature's Way version of Vitamin D3, but I
can find no documentation as to what is the source of the D3 in that product.
Q. I have a question regarding the source of Vitamin D. I
understand cholecalciferol or D3 has the origin from animal products such as
sheep wool and hides. Also, I read somewhere that vegans usually obtain vitamin
D from the action of sunlight on the skin or by taking fortified foods such as soya milk, margarine, breakfast cereals and vitamin supplements which are made
from yeast or other fungi. Fortified vegan products contain D2 ( ergocalciferol
). Vegans are careful about their source of Vitamin D as D3 ( Cholecalciferol )
which is animal-derived.
A. It appears to be true that Vitamin D in the form of
cholecalciferol is derived from sheep wool. Therefore, this would make
it fine for a vegetarian but not for a strict vegan. The sheep are not killed.
The wool is sheared, and lanolin from the sheep wool is chemically altered in
the lab to produce vitamin D3 or cholecalciferol.
Q. Can you explain the difference between vitamin D
deficiency symptoms and vitamin D signs?
A. Vitamin D deficiency symptoms refer to various symptoms that a
patient notices, but the phrase Vitamin D deficiency signs refers to those signs
noticeable by a doctor.
Q. I live in the UK and due to the lack of sunshine, would
like to buy a Vitamin D supplement. However, i am now completely confused ! I
have just read the new study from Australia ( Science Daily Jan. 27, 2008 ) that
suggests taking a Vitamin D supplement ORALLY is BAD for you. Its actually a
pretty damning study regarding ORAL Vitamin D .. It says: "ingested vitamin D is
immunosuppressive and that low blood levels of vitamin D may be actually a
result of the disease process. Supplementation may make the disease worse.
Vitamin D deficiency, long interpreted as a cause of disease, is more likely the
result of the disease process, and increasing intake of vitamin D often makes
the disease worse We have found that vitamin D supplementation, even at levels
many consider desirable, interferes with recovery in these patients. Vitamin D
is a secosteroid hormone, and the body regulates the production of all it needs.
In fact, the use of supplements can be harmful, because they suppress the immune
system so that the body cannot fight disease and infection effectively. The
comprehensive studies are just not showing that supplementary vitamin D makes
people healthier. The Science Daily article, dated 28 Jan 08.
What is your opinion on this new study ? This has put me off buying
any Vitamin D supplements completely and would appreciate your thoughts.
A. Different scientists have different opinions regarding nutrition
and supplement use. The reason is that this field is extremely complicated and
it is difficult to do well-controlled long term studies. Furthermore, different
results could be obtained depending on the dosage used for the vitamin or
supplement or in different populations or groups of patients. For instance, it
is possible that opposite results could be obtained by providing vitamin D at
200 units a day versus 1,000 units a day, even though it is the same vitamin.
For the time being, I think taking a vitamin D supplement at 400 units a few
times a week probably provides more benefits than harm to those who live in
climates where there is little sun exposure or little vitamin D in the foods
people ingest.
There is a four year long vitamin D study that has interesting
results.
Vitamin D and calcium supplementation reduces cancer risk: results of a
randomized trial.
Am J Clin Nutr. 2007 June;85(6):1586-91.Lappe JM, Travers-Gustafson D,
Davies KM, Recker RR, Heaney RP. Osteoporosis Research Center, Creighton
University, Omaha, NE 68131, USA.
The purpose of this analysis was to determine the efficacy of calcium alone
and calcium plus vitamin D in reducing incident cancer risk of all types. This
was a 4-y, population-based, double-blind, randomized placebo-controlled trial.
The primary outcome was fracture incidence, and the principal secondary outcome
was cancer incidence. The subjects were 1179 community-dwelling women randomly
selected from the population of healthy postmenopausal women aged >55 y in a
9-county rural area of Nebraska centered at latitude 41.4 degrees N. Subjects
were randomly assigned to receive 1400-1500 mg supplemental calcium/d alone
(Ca-only), supplemental calcium plus 1100 IU vitamin D3 / d (Ca + D), or
placebo. Cancer incidence was lower in the Ca + vitamin D women than in the
placebo control subjects. In conclusion, Improving calcium and vitamin D
nutritional status substantially reduces all-cancer risk in postmenopausal
women.
Q. I read with interest your take on potential problems
with higher supplemental doses of Vitamin D and calcium. I, myself, have been
diagnosed with very low bone density and, at the time of diagnosis, my Vitamin D
(25-OH) was 10 nanograms per ml. I have subsequently -- and under monitoring -- taken 4,000 I.U.
of D3 and still only managed to raise my levels to 39. I am now taking 5,000 I.U.
and due to be tested soon. I know of several people who are taking Vitamin D3
doses in the 4-6,000 I.U. range and still maintaining what are considered to be
barely adequate levels of D (around 50). One is having her parathyroid levels
measured at the same time and, at 6,000 I.U., has noticed no problems. In a
study in Hawaii of subjects who reported 22.4 hours average sun exposure without
sunscreen, 51% were reported to be Vitamin D deficient. My question is: if even
"heroic" doses of Vitamin D3 are merely
maintaining what are considered desirable levels, can these doses still pose
potential health problems?
A. It's difficult to say. Blood levels of vitamin D may not
necessarily reflect what is actually going on in bone tissue, brain
tissue, or other parts of the body. Many doctors overly rely on blood levels to determine
the proper dosage of
vitamins, drugs, and hormones, but blood tests do not always reflect
accurately the levels or effects of these medications in various tissues of
the body or what is actually going on within each cell. There could be a
normal level of the vitamin or medication in the blood stream yet untoward
effects could be going on in some part of the body. For instance, if a person
takes DHEA and their blood test shows the level to be within the normal range,
it is possible that the levels in hair tissue could be high causing hair loss.
Same with vitamin D. It is possible that blood levels could be low or normal,
yet untoward reactions could be occurring in other tissues, such as brain
tissue.
Q. This note is just to let you know that there is another
side-effect of high vitamin D supplementation, that you may not be aware of:
whole-body anxiety. (This was a surprise to my doctor.) My medical history is
that I acquired hypothyroidism due to destruction of my thyroid by Hashimoto's
autoimmune thyroiditis; the Hashimoto was perhaps caused by gluten. I also
acquired multiple nutritional deficiencies as the result of gluten enteropathy.
Autoimmune problems and enteropathy are commonly found in persons, like me,
whose gluten sensitivity is not promptly diagnosed. After getting off gluten in
2003, the process of
finding and fixing the many nutritional deficiencies the enteropathy caused, has
been lengthy. Early in 2008 I discovered that taking vitamin D3 caused me to go
into diagnosed hyperthyroidism (TSH < 0.015). I had to lower my T4 dose from its
high of 118mcg. After taking up to 3000 IU D3 daily for 5 months and finally
achieving D sufficiency at 50ng/ml, I dropped back to about
600 IU D3 daily. Reducing the level of D supplementation, improved the way I
feel. Apparently high blood levels of vitamin D are excitatory for some people,
because the 3000 IU vitamin D supplementation had created a whole-body anxiety
situation. It had also interfered with my thyroid treatment; taking T4 while I
also had a high blood level of D3, would cause intense anxiety, so I had
throttled back my T4 dose to a low level (usually 12mcg per day) that wasn't
sufficient to keep my TSH reasonably low and my FT3 and FT4 both within the
normal ranges. Based on what you said in your column, I've taken your advice and
also reduced my calcium supplementation.
I have a friend whose son was put on high vitamin D supplementation
after he was found to have gluten sensitivity, and have multiple deficiencies.
The doc put him on a dose of 8000 IU D3 as drops, once per week. When I talked
to his mom about my experience with high-dose vitamin D supplementation, she
found it interesting. She told me that when she gives her son his 8000 IU D3 on
Sunday, he acts "crazy" on Monday. So evidently I'm not the only person who
finds that high blood levels of vitamin D3 are excitatory.
Q. I recently went to see a new Internist that practices
Integrative Medicine (combines Eastern and Western Medicine). He has his own
line of nutraceuticals. His name is Dr. Michael Hirt out of Tarzana, Ca. Dr.
Michael Hirt came highly recommended. At my first visit recently he drew my
blood and said that I am deficient in Vitamin D. He recommends that I take 3,000
i.u. per day. It sounds like it's too much, since your website says to take from
200-600 i.u. per day and every one else recommends around 400 i.u. per day. What
is your take on this? Is this way too much? I am 48 y.o. and suffer from Type 2
diabetes, chronic fatigue syndrome, obstructive sleep apnea, obesity and a whole
host of other health problems. I have no energy. I just don't want to take such
high doses of vitamin D if its truly not warranted and maybe end up with other
health problems due to vitamin D overdose.
A. Research regarding the ideal dosage of vitamin D supplementation
is still in its early stages and different doctors have different opinions
regarding the right vitamin D dosage to prescribe to their patients. It also
depends on the blood studies as to how deficient a person is, and how long the
vitamin D treatment needs to continue. Personally I prefer to use lower dosages
of prescription medications and supplements than other doctors but this is my
approach. Other doctors have different viewpoints.
Q. I am an older male with a prostate enlargement and I
use
saw palmetto
herb daily along with a
pygeum africanum
extract. Just wondering whether 400 units of vitamin D has any interactions with
other supplements. I also occasionally use a potent aphrodisiac called
tongkat ali
herb.
A. This low vitamin D dosage should not interfere with other herbal
products.
I read Dr. Sahelian's comments about supplements
regularly, but I was intrigued by his recommendations for D3. That low
recommendation of 400 I.U. for adults has been considered too low for some time
now, especially with the research he is certainly aware of, by well known
researchers like Michael Holick and Reinhold Veith, as examples. As is often the
case in medicine with nutritional supplementation, vitamin D supplementation has
been considered most conservatively, despite the rare instances of toxicity.
Holick and other researchers are now suggesting, due to widespread evidence,
that up to 10,000 I.U. is a safe daily dose. Perhaps, rather than just recite
outdated recommendations which completely confuse the otherwise uninformed
reader, as occurred in the questions and comments on the webpage, there should
be a caveat that guides the reader to consider supplementation levels after they
have their serum levels checked. After all, latitude, occupation, and general
health status, and most certainly genetics will certainly produce a widely
divergent initial serum level. For example, a Puerto Rican farmer had a serum
level of 220 nmole/L and had no evidence of hypercalcemia, while up here in the
Pacific NW, most of my patients are tested and reveal a level below 20 nmole/L.
I am a chiropractor in Arlington, VA. A few articles apropos of this email: Webb
AR, Kline L, Holick MF. Influence of season and latitude on the cutaneous
synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will
not promote vitamin D3 synthesis in human skin. J Clin Endocrinol Metab.
1988;67:373-378. Vieth R, Bischoff-Ferrari H, Boucher BJ. The urgent need to
recommend an intake of vitamin D that is effective. Am J Clin Nutr.
2007;85:649-650. Vieth R, Ladak Y, Walfish PG: Age-Related Changes in the
25-Hydroxyvitamin D Versus Parathyroid Hormone Relationship Suggest a Different
Reason Why Older Adults Require More Vitamin D. J Clin Endocrinol Metab 2003,
88:185-191. Vieth R, Kimball S, Hu A, Walfish PG. Randomized comparison of the
effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on
biochemical responses and the wellbeing of patients. Nutrition J. 2004;3:8.
Throughout medical and nutritional research history there are
countless examples of medications or supplements that researchers have been
excited about and began recommending large dosages only later to find out that
there were unknown long term side effects that did not appear initially. As to
vitamin D, I suggest, as a general guideline, a supplement dosage of 400 to 1000
units a day for most people with exception regarding sun exposure and dietary
intake. See my section on potential vitamin D side effects.
I respectively disagree with your evaluation of Vitamin D3
supplements. I have taken Centrum Silver Supplements for many years. In July
2008 I was tested for Vitamin D and the level was 22 ng/ml. According to all
sources I can find, a minimum level of 30 ng/ml is required. Many Canadian
studies, and those in the US indicate that blood levels higher than 30ng/ml,
closer to 50 or 60 ng/ml are beneficial in preventing heart attacks, colon
cancer, slowing prostate cancer, and increasing both bone health and the immune
system functoin. I currently live in NYC, and take 4500 IU vitamin D/day. My
vitamin D level is 57ng/ml as of October 2009. I have my doctor's approval. I
also have metastatic prostate cancer with very low PSA readings.
Each person is entitled to their own opinion on this topic
and all others.
I read your latest newsletter with interest. In general, I
have appreciated your conservative approach to vitamins and supplements. On
vitamin D, however, I'm not sure I agree with you. No question, we need longer
term tests in humans. However, the present evidence shows that high doses of D-3
may prevent cancers, colds, the flu, etc. Testing (at Labcorp only) prevents
overdoses. Another alternative, although expensive, is to use tanning beds. I am
aware of the UVA, UVB issues.
Some doctors and people are more cautious than others in
terms of recommended dosages. I am not sure anyone as of 2009 knows for certain
the appropriate dosages that would apply to everyone.
From your October 2009 newsletter: "Vitamin D taken in
high amounts can cause excessive calcification of bone, calcification of soft
tissue, kidney stones, headaches, weakness, nausea, and vomiting." Are you
talking about increasing Vit D levels to over the 'normal' range, or taking
doses that are in excess, like 10,000 to 20,000 units at once? What about sun
exposure, where one may produce the same amount at once? In practice I am seeing
that most of my chronic pain, depressed, fatigued, patients are very low in Vit
D (15-25, with "normal" being 40-80). Are these people better off with these low
levels, or supplementing to increase these levels?
The above side effects you mention are due to excessive
intake of 20,000 units or more taken for several weeks. I am concerned about the
long term side effects of taking more than 2000 units for several years.
Thank you for addressing this matter of vitamin D, an
often misunderstood vitamin / hormone. I would like point out that UVB light
(which promotes vitamin D production) is not available above 38 degrees N
latitude (as in the Bay Area and northward) during the dark months (November
through February). Also, dark-skinned folk living at these latitudes above 30
degrees may need more exposure to the sun than their paler colleagues. Finally,
if one measures 25 hydroxy vitamin D3 as a reference point for adequate vitamin
D levels in the body, and regularly finds them pitifully low, would not that
suggest that 400 IU is rather low for daily intake? There is some consideration
now being given that 1000 IU should be the new RDA (not that RDAs represent
optimal levels). Drs. John Cannell, Michael Holick, Reinhold Vieth, and William
Grant have done extensive research on vitamin D, which I hope you have had the
opportunity to review.
It is possible that 1,000 units should be the new RDA but I
prefer waiting a few more years for additional research before making widespread
recommendations.
Apparently, as of November 2009, you consider
supplementation beyond 1000 IUs of vitamin D to be excessive. I have a question:
do you have an objective basis to assert that larger amounts, for sake of
example let's say 4000 IUs, are excessive? I ask because 4000 IUs of vitamin D
is a mere one ten-thousandths of a gram of the vitamin. Is that really a large
amount? One ten-thousandths of a gram doesn't sound to me even remotely as large
as 4000! Are you, perhaps, suffering from being unreasonably impressed about the
large numbers when quoted in IUs as SOUNDING like they are large numbers? If the
dosage amounts were, instead, being quoted in micrograms, would you still hold
the same view? As I am sure you realize, those on the opposite side of the fence
claim that the tiny amounts of the vitamin currently recommended in the RDAs are
adequate only to prevent rickets. While, they say, there is other serious
evidence which demonstrates that appreciably larger intakes are necessary to
prevent quite a few other very serious health issues. They also point out that
people taking even much larger amounts than 4000 IUs daily have serum levels
that are nowhere remotely close to those that have been found to represent
toxicity. I am truly open-minded about this, and am very happy to listen to
evidence on both sides.
Each vitamin, mineral, herb, nutrient and medication has to
be evaluated individually as to its appropriate dosage as opposed to comparing
it dosage-wise to others. Some poisons can kill in less than microgram amounts
whereas other chemicals are safe in mg or gram amounts. The use of microgram or
mg has nothing to do with the consideration of safety. Those who advocate large
dosage use of vitamin D are the ones who are responsible in providing evidence
of safety over years and decades of use and they need to provide evidence that
longevity is increased by the use of this vitamin in the daily range of
thousands of IUs. Thus far there are no studies to show whether the general
population in the United States would be better off ingesting several thousand
units of this vitamin. There are no longer term studies that indicate that
having a particular blood level of vitamin D will make you live longer. A
reasonable and cautious medical doctor or scientist does not make haphazard and
careless recommendations of high dose supplement use without adequate evidence
of long term safety. There are countless dietary supplements that have shown to
have a positive role to play in improving health, at least in the short term. If
you read all these enthusiastic reports on certain websites you will end up
being convinced that you need to take dozens or hundreds of vitamins, nutrients,
and various herbs, fruit and vegetable extracts, amino acids, hormones, etc in
high dosages. Not only is this expensive, but we have no idea of all the
interactions that could occur, positive or negative.