What are normal vitamin D levels?
Dec 19, · In , the venerable Institute of Medicine (IOM) issued a report based on lengthy examination of data by a group of experts. To sum up, they estimated that a vitamin D level of 20 ng/mL or higher was adequate for good bone health, and subsequently a level below 20 was considered a vitamin D deficiency. 4 rows · Jul 10, · Normal vitamin D levels in the blood are 20 ng/ml or above for adults. People aged 1–70 years.
For pevel adults, a normal level of vitamin D in the blood is 20 nanograms per milliliter or above. The amount of vitamin D a person needs per day depends on their age. The body depends on vitamin D for a variety of reasons, but it is especially important for bone health. According to the Office of Dietary Supplementsthe following are the minimum amounts of hsould D a person needs per day:.
Doctors use blood tests to determine if someone has adequate levels of vitamin D. A person can talk to their doctor to get a better understanding of what their blood test results mean. According to what to expect during 12th week of pregnancy U.
Department of Agriculturevitamin D helps the body absorb calcium and phosphorus, both vital minerals for building strong bones. Without adequate vitamin D, a person may develop soft, weak, or brittle bones. This can cause conditions such as rickets in children, or osteomalacia and osteoporosis in adults. Evidence suggests vitamin D may help to prevent some medical conditions, including some types of cancer. However, scientists are still trying to understand how vitamin D may influence whta conditions.
Research into its ability to influence diseases, such as diabeteshypertensionand multiple sclerosisis ongoing. People can get vitamin D from exposure to sunlight or, to a lesser extent, from food. If someone does not get enough vitamin D from these sources, they may develop a deficiency. The symptoms of a vitamin D deficiency can be subtlebut the classic symptoms are bone aches and muscle weakness. Department of Health and Human Servicessome people are more at risk of developing vitamin D deficiency than others.
This includes:. Some health conditions and medications can also make it more difficult for someone to absorb vitamin D, including:. People can get at least some of their wyat vitamin D from exposure to sunlight. However, as light levels vary, depending on location and the time of year, a person may not be able to get all the vitamin D they need from sunlight.
A study in Switzerland found that only 10—15 minutes of sun exposure per day was enough to provide 1, IU of vitamin D in spring and summer. However, getting this amount in fall and winter was unrealistic, requiring someone to spend over 6 hours vktamin day outdoors. This suggests that people who live in colder climates, or who spend most of their time indoors, may benefit from vitamin D supplements. However, a person should talk to their doctor before taking vitamin D, as it can interact with some medications.
Sunlight can also cause skin damage and sunburnso it is essential to use sunscreen when spending time outside. A study on Australian office workers found that applying sunscreen meant how to make rice milk soap could spend more time outdoors, leading to higher vitamin D levels overall.
People can also get some of their vitamin D from food. According to the Office of Dietary Supplementsfood sources of vitamin D include:. The study on Australian office workers found that fish consumption, in particular, had a positive effect on vitamin D levels during winter. A person can take too shoulv vitamin D. Since vitamin D occurs naturally in only a few food sources, the most likely way a person can get too much vitamin D is through taking a high strength supplement.
According to one studyvitamin D toxicity can produce symptoms that include:. The upper limits for you much vitamin D a person should take per day by age, are as follows:. A person should see a doctor if they notice the symptoms of vitamin D toxicity. A person should also see their doctor if they notice symptoms of a lack of vitamin D. A doctor may do a physical examination, ask questions, or perform a blood test to see if the person has a deficiency. People aged 1—70 years should aim to get at least 15 mcg or IU of vitamin D per day.
Those who are older or at risk for a deficiency may require more. Vitamin D is an essential nutrient for a variety of reasons, particularly for bone health.
A person will often get enough vitamin D from sunlight, but if they are at risk for a deficiency, they may benefit from taking a supplement.
The body produces vitamin D in response kevel sun exposure. Vitamin D has a range of benefits. It protects the teeth and bones and defends against….
A vitamin D deficiency is common, and it can lead to further health issues. Still, many people with the deficiency have no symptoms. What is the longest vga cable more here. Even a short time in the sun can provide all the vitamin D a person needs for the day.
Learn how to get the most vitamin D from the sun, and other…. Vitamin D can improve bone, muscle, and immune system health. Foods with a high vitamin D content include oily fish, some mushrooms, and egg yolks…. Vitamin D is a crucial nutrient for bone health. Some studies suggest a link between vitamin D deficiency and joint or muscle pain, including….
What are normal vitamin D levels? Medically reviewed by Deborah Weatherspoon, Ph. Normal levels Function Deficiency Sources Overdose When to see a doctor Summary For most adults, a normal level of vitamin D in the blood is 20 nanograms per milliliter or above.
Normal vitamin D levels. Share on Pinterest Exposure to sunlight can help a person get enough vitamin D. Why vitamin D is important. Vitamin D deficiency. How to increase vitamin D levels. Can you take too much? When to see a doctor. Mouse study reveals brain pathways linked to Parkinson's. How diet influences gut bacteria and inflammation. Related Coverage. What are the health benefits of vitamin D? Medically reviewed by Debra Sullivan, Ph.
What are the symptoms of a vitamin D deficiency? Medically reviewed by Kevin Martinez, MD. How to get more vitamin D from the sun.
Medically reviewed by Stacy Sampson, D. What are the best dietary sources shold vitamin D? Can vitamin D relieve joint pain?
Medically sgould by William Morrison, M.
What Is Vitamin D?
Mar 24, · The Endocrine Society states, for example, that to maintain serum 25 (OH)D levels above 75 nmol/L (30 ng/mL), adults might need at least to 50 mcg (1,–2, IU)/day of supplemental vitamin D, and children and adolescents might need at least 25 mcg (1, IU)/day [ 11 ]. Normal 1,25 (OH) 2 vitamin D levels run between 12 and 55 pg/ml. This is the activated form of vitamin D. And normal parathyroid hormone levels run between 12 and 50 pg/ml. These are not the first two levels your doctor should be looking for. Feb 09, · The recommended daily amount of vitamin D is international units (IU) for children up to age 12 months, IU for people ages 1 to 70 years, and IU for people over 70 years.
Get the latest public health information from CDC. Have a question? This is a fact sheet intended for health professionals. For a reader-friendly overview of Vitamin D, see our consumer fact sheet on Vitamin D. Vitamin D also referred to as "calciferol" is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet UV rays from sunlight strike the skin and trigger vitamin D synthesis.
Vitamin D obtained from sun exposure, foods, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first hydroxylation, which occurs in the liver, converts vitamin D to hydroxyvitamin D [25 OH D], also known as "calcidiol.
Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralization and to prevent hypocalcemic tetany involuntary contraction of muscles, leading to cramps and spasms. It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts [ ].
Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps protect older adults from osteoporosis.
Vitamin D has other roles in the body, including reduction of inflammation as well as modulation of such processes as cell growth, neuromuscular and immune function, and glucose metabolism [ ]. Many genes encoding proteins that regulate cell proliferation, differentiation, and apoptosis are modulated in part by vitamin D.
In foods and dietary supplements, vitamin D has two main forms, D 2 ergocalciferol and D 3 cholecalciferol , that differ chemically only in their side-chain structures. Both forms are well absorbed in the small intestine. Absorption occurs by simple passive diffusion and by a mechanism that involves intestinal membrane carrier proteins [ 4 ]. The concurrent presence of fat in the gut enhances vitamin D absorption, but some vitamin D is absorbed even without dietary fat. Neither aging nor obesity alters vitamin D absorption from the gut [ 4 ].
Serum concentration of 25 OH D is currently the main indicator of vitamin D status. It reflects vitamin D produced endogenously and that obtained from foods and supplements [ 1 ]. In serum, 25 OH D has a fairly long circulating half-life of 15 days [ 1 ]. Assessing vitamin D status by measuring serum 25 OH D concentrations is complicated by the considerable variability of the available assays the two most common ones involve antibodies or chromatography used by laboratories that conduct the analyses [ 5 , 6 ].
As a result, a finding can be falsely low or falsely high, depending on the assay used and the laboratory. The international Vitamin D Standardization Program has developed procedures for standardizing the laboratory measurement of 25 OH D to improve clinical and public health practice [ 5 , ]. In contrast to 25 OH D, circulating 1,25 OH 2D is generally not a good indicator of vitamin D status because it has a short half-life measured in hours, and serum levels are tightly regulated by parathyroid hormone, calcium, and phosphate [ 1 ].
Levels of 1,25 OH 2D do not typically decrease until vitamin D deficiency is severe [ 2 ]. Researchers have not definitively identified serum concentrations of 25 OH D associated with deficiency e. Optimal serum concentrations of 25 OH D for bone and general health have not been established because they are likely to vary by stage of life, by race and ethnicity, and with each physiological measure used [ 1 , 13 , 14 ]. In addition, although 25 OH D levels rise in response to increased vitamin D intake, the relationship is nonlinear [ 1 ].
The amount of increase varies, for example, by baseline serum levels and duration of supplementation. DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:.
An FNB committee established RDAs for vitamin D to indicate daily intakes sufficient to maintain bone health and normal calcium metabolism in healthy people.
Even though sunlight is a major source of vitamin D for some people, the FNB based the vitamin D RDAs on the assumption that people receive minimal sun exposure [ 1 ]. Many other countries around the world and some professional societies have somewhat different guidelines for vitamin D intakes [ 15 ]. These differences are a result of an incomplete understanding of the biology and clinical implications of vitamin D, different purposes for the guidelines e.
Food Few foods naturally contain vitamin D. The flesh of fatty fish such as trout, salmon, tuna, and mackerel and fish liver oils are among the best sources [ 17 , 1 ]. An animal's diet affects the amount of vitamin D in its tissues.
Beef liver, cheese, and egg yolks have small amounts of vitamin D, primarily in the form of vitamin D 3 and its metabolite 25 OH D 3. Mushrooms provide variable amounts of vitamin D 2 [ 17 ]. Some mushrooms available on the market have been treated with UV light to increase their levels of vitamin D 2.
In addition, the Food and Drug Administration FDA has approved UV-treated mushroom powder as a food additive for use as a source of vitamin D 2 in food products [ 18 ]. Very limited evidence suggests no substantial differences in the bioavailability of vitamin D from various foods [ 19 ]. Animal-based foods typically provide some vitamin D in the form of 25 OH D in addition to vitamin D 3.
The impact of this form on vitamin D status is an emerging area of research. Studies show that 25 OH D appears to be approximately five times more potent than the parent vitamin for raising serum 25 OH D concentrations [ 17 , 20 , 21 ]. One study found that when the 25 OH D content of beef, pork, chicken, turkey, and eggs is taken into account, the total amount of vitamin D in the food is 2 to 18 times higher than the amount in the parent vitamin alone, depending on the food [ 20 ].
Fortified foods provide most of the vitamin D in American diets [ 1 , 22 ]. For example, almost all of the U. In Canada, milk must be fortified with 0. Other dairy products made from milk, such as cheese and ice cream, are not usually fortified in the United States or Canada. Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, margarine, and other food products.
The United States mandates the fortification of infant formula with 1—2. The U. Sun exposure Most people in the world meet at least some of their vitamin D needs through exposure to sunlight [ 1 ].
Type B UV UVB radiation with a wavelength of approximately — nanometers penetrates uncovered skin and converts cutaneous 7-dehydrocholesterol to previtamin D 3 , which in turn becomes vitamin D 3. Season, time of day, length of day, cloud cover, smog, skin melanin content, and sunscreen are among the factors that affect UV radiation exposure and vitamin D synthesis.
Older people and people with dark skin are less able to produce vitamin D from sunlight [ 1 ]. UVB radiation does not penetrate glass, so exposure to sunshine indoors through a window does not produce vitamin D [ 27 ]. The factors that affect UV radiation exposure, individual responsiveness, and uncertainties about the amount of sun exposure needed to maintain adequate vitamin D levels make it difficult to provide guidelines on how much sun exposure is required for sufficient vitamin D synthesis [ 15 , 28 ].
Some expert bodies and vitamin D researchers suggest, for example, that approximately 5—30 minutes of sun exposure, particularly between 10 a. But despite the importance of the sun for vitamin D synthesis, limiting skin exposure to sunlight and UV radiation from tanning beds is prudent [ 28 ].
UV radiation is a carcinogen, and UV exposure is the most preventable cause of skin cancer. Federal agencies and national organizations advise taking photoprotective measures to reduce the risk of skin cancer, including using sunscreen with a sun protection factor SPF of 15 or higher, whenever people are exposed to the sun [ 28 , 30 ]. In practice, however, people usually do not apply sufficient amounts of sunscreen, cover all sun-exposed skin, or reapply sunscreen regularly.
Their skin probably synthesizes some vitamin D, even with typically applied sunscreen amounts [ 1 , 28 ]. Dietary supplements Dietary supplements can contain vitamins D 2 or D 3.
Vitamin D 2 is manufactured using UV irradiation of ergosterol in yeast, and vitamin D 3 is produced with irradiation of 7-dehydrocholesterol from lanolin and the chemical conversion of cholesterol [ 13 ]. Both forms raise serum 25 OH D levels, and they seem to have equivalent ability to cure rickets [ 4 ]. In addition, most steps in the metabolism and actions of vitamins D 2 and D 3 are identical. However, most evidence indicates that vitamin D 3 increases serum 25 OH D levels to a greater extent and maintains these higher levels longer than vitamin D 2 , even though both forms are well absorbed in the gut [ ].
Some studies have used dietary supplements containing the 25 OH D 3 form of vitamin D. Per equivalent microgram dose, 25 OH D 3 is three to five times as potent as vitamin D 3 [ 35 , 36 ]. However, no 25 OH D 3 dietary supplements appear to be available to consumers on the U. Most people in the United States consume less than recommended amounts of vitamin D. Total vitamin D intakes were three times higher with supplement use than with diet alone; the mean intake from foods and beverages alone for individuals aged 2 and older was 4.
Some people take very high doses of vitamin D supplements. In —, an estimated 3. One might expect a large proportion of the U. However, comparing vitamin D intakes to serum 25 OH D levels is problematic. One reason is that sun exposure affects vitamin D status, so serum 25 OH D levels are usually higher than would be predicted on the basis of vitamin D dietary intakes alone [ 1 ].
Another reason is that animal foods contain some 25 OH D. This form of vitamin D is not included in intake surveys and is considerably more potent than vitamins D 2 or D 3 at raising serum 25 OH D levels [ 41 ]. Proportions at risk of deficiency were lowest among children aged 1—5 years 0. Rates of deficiency varied by race and ethnicity: Again, the pattern was similar for the risk of inadequacy.
Vitamin D status in the United States remained stable in the decade between — and — People can develop vitamin D deficiency when usual intakes are lower over time than recommended levels, exposure to sunlight is limited, the kidneys cannot convert 25 OH D to its active form, or absorption of vitamin D from the digestive tract is inadequate.
Diets low in vitamin D are more common in people who have milk allergy or lactose intolerance and those who consume an ovo-vegetarian or vegan diet [ 1 ].
In children, vitamin D deficiency is manifested as rickets, a disease characterized by a failure of bone tissue to become properly mineralized, resulting in soft bones and skeletal deformities [ 43 ]. In addition to bone deformities and pain, severe rickets can cause failure to thrive, developmental delay, hypocalcemic seizures, tetanic spasms, cardiomyopathy, and dental abnormalities [ 44 , 45 ].
Prolonged exclusive breastfeeding without vitamin D supplementation can cause rickets in infants, and, in the United States, rickets is most common among breastfed Black infants and children [ 46 ]. In one Minnesota county, the incidence rate of rickets in children younger than 3 years in the decade beginning in was Rickets occurred mainly in Black children who were breastfed longer, were born with low birthweight, weighed less, and were shorter than other children.
The incidence rate of rickets in the infants and children younger than 7 seen by 2, pediatricians throughout Canada was 2. The fortification of milk a good source of calcium and other staples, such as breakfast cereals and margarine, with vitamin D beginning in the s along with the use of cod liver oil made rickets rare in the United States [ 28 , 49 ].