Also indexed as
1,25-dihydroxyvitamin D, Calciferol, Calcipotriol, Cholecalciferol, Ergocalciferol, Irradiated Ergocalciferol
Introduction
Introduction
The fat-soluble vitamin D’s most important role is maintaining blood levels of calcium, which it accomplishes by increasing absorption of calcium from food and reducing urinary calcium loss. Both effects keep calcium in the body and therefore spare the calcium that is stored in bones. When necessary, vitamin D transfers calcium from the bone into the bloodstream, which does not benefit bones. Although the overall effect of vitamin D on the bones is complicated, some vitamin D is necessary for healthy bones and teeth.
Where is it found?
Cod liver oil is an excellent dietary source of vitamin D, as are vitamin D-fortified foods. Traces of vitamin D are found in egg yolks and butter. However, the majority of vitamin D in the body is created during a chemical reaction that starts with sunlight exposure to the skin. Cholecalciferol (vitamin D3) is the animal form of this vitamin.
Vitamin D has been used in connection with the following conditions (refer to the individual health concern for complete information):
Science Ratings - Health Concerns
*** - Crohn’s disease
*** - Cystic fibrosis
*** - Osteoporosis
*** - Rickets/osteomalacia
** - Burns (severe)
** - Celiac disease (for deficiency only)
** - Depression
** - Hypertension (for deficiency only)
** - Prostate cancer
** - Seasonal affective disorder
** - Type 1 diabetes
** - Type 2 diabetes
* - Alcohol withdrawal support
* - Amenorrhea (calcium for preventing bone loss)
* - Breast cancer (reduces risk)
* - Cardiac arrhythmia
* - Colon cancer (reduces risk)
* - Migraine headaches
* - Multiple sclerosis
* - Parkinson’s disease
* - Vitiligo (topical calcipotriol only)
*** - Reliable and relatively consistent scientific data showing a substantial health benefit.
Where is it found?
Cod liver oil is an excellent dietary source of vitamin D, as are vitamin D-fortified foods. Traces of vitamin D are found in egg yolks and butter. However, the majority of vitamin D in the body is created during a chemical reaction that starts with sunlight exposure to the skin. Cholecalciferol (vitamin D3) is the animal form of this vitamin.
Vitamin D has been used in connection with the following conditions (refer to the individual health concern for complete information):
Science Ratings - Health Concerns
*** - Crohn’s disease
*** - Cystic fibrosis
*** - Osteoporosis
*** - Rickets/osteomalacia
** - Burns (severe)
** - Celiac disease (for deficiency only)
** - Depression
** - Hypertension (for deficiency only)
** - Prostate cancer
** - Seasonal affective disorder
** - Type 1 diabetes
** - Type 2 diabetes
* - Alcohol withdrawal support
* - Amenorrhea (calcium for preventing bone loss)
* - Breast cancer (reduces risk)
* - Cardiac arrhythmia
* - Colon cancer (reduces risk)
* - Migraine headaches
* - Multiple sclerosis
* - Parkinson’s disease
* - Vitiligo (topical calcipotriol only)
*** - Reliable and relatively consistent scientific data showing a substantial health benefit.
** - Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
* - For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.
Who is likely to be deficient?
In adults, vitamin D deficiency may result in a softening of the bones known as osteomalacia. This condition is treated with vitamin D, sometimes in combination with calcium supplements. Osteomalacia should be diagnosed, and its treatment monitored, by a doctor. In people of any age, vitamin D deficiency causes abnormal bone formation. It occurs more commonly following winter, owing to restricted sunlight exposure during that season. Living in an area with a lot of atmospheric pollution, which can block the sun's ultraviolet rays, also appears to increase the risk of vitamin D deficiency.1
Vitamin D deficiency is more common in strict vegetarians (who avoid vitamin D-fortified dairy foods), dark-skinned people,2 alcoholics, and people with liver or kidney disease. People with liver and kidney disease can make vitamin D but cannot activate it.
Vitamin D deficiency is more common in people suffering from intestinal malabsorption, which may have occurred following previous intestinal surgeries, or from celiac disease.3 People with insufficient pancreatic function (e.g., those with pancreatitis or cystic fibrosis) tend to be deficient in vitamin D. Vitamin D deficiency is also common in individuals with hyperthyroidism (Graves' disease), particularly women.4
In children, vitamin D deficiency is called rickets and causes a bowing of bones not seen in adults with vitamin D deficiency. Vitamin D deficiency is common among people with hyperparathyroidism, a condition in which the parathyroid gland is overactive. In a study of 124 people with mild hyperparathyroidism, vitamin D levels were below normal in 7% of them and suboptimal in 53% of them.5 Vitamin D deficiency is also common in men with advanced prostate cancer. In one study, 44% of 16 men with advanced prostate cancer had decreased blood levels of vitamin D.6
One in seven adults has been reported to be deficient in vitamin D.7 In one study, 42% of hospitalized patients under age 65 were reported to be vitamin D deficient.8 In this same study, 37% of the people were found to be deficient in vitamin D, despite the fact they were eating the currently recommended amount of this nutrient. Vitamin D deficiency is particularly common among the elderly. Age-related decline in vitamin D status may be due to reduced absorption, transport, or liver metabolism of vitamin D.9
How much is usually taken?
People who get plenty of sun exposure do not require supplemental vitamin D, since sunlight increases vitamin D synthesis when it strikes bare skin. Although the recommended dietary allowance for vitamin D is 200 IU per day for adults, there is some evidence that elderly people need 800 to 1,000 IU per day for maximum effects on preserving bone density and preventing fractures.10 11 12 13 Sun-deprived people should take no less than 600 IU per day and ideally around 1,000 IU per day.14 15
Are there any side effects or interactions?
People with hyperparathyroidism should not take vitamin D without consulting a physician. People with sarcoidosis should not supplement with vitamin D, unless a doctor has determined that their calcium levels are not elevated. Too much vitamin D taken for long periods of time may lead to headaches, weight loss, and kidney stones. Rarely, excessive vitamin D may even lead to deafness, blindness, increased thirst, increased urination, diarrhea, irritability, children’s failure to gain weight, or death.
Most people take 400 IU per day, a safe amount for adults. Some researchers believe that amounts up to 10,000 IU per day are safe for the average healthy adult, although adverse effects may occur even at lower levels among people with hypersensitivity to vitamin D (e.g. hyperparathyroidism).16 In fact, of all published cases of vitamin D toxicity for which a vitamin D amount is known, only one occurred at a level of intake under 40,000 IU per day.17 Nevertheless, people wishing to take more than 1,000 IU per day for long periods of time should consult a physician. People should remember the total daily intake of vitamin D includes vitamin D from fortified milk and other fortified foods, cod liver oil, supplements that contain vitamin D, and sunlight. People who receive adequate sunlight exposure do not need as much vitamin D in their diet as do people who receive minimal sunlight exposure.
Vitamin D increases both calcium and phosphorus absorption and has also been reported to increase absorption of aluminum. Increased blood levels of calcium (which may be a marker for vitamin D status) have been linked to heart disease.18 Some,19 but not all,20 research suggests that vitamin D may slightly raise blood levels of cholesterol in humans.
Who is likely to be deficient?
In adults, vitamin D deficiency may result in a softening of the bones known as osteomalacia. This condition is treated with vitamin D, sometimes in combination with calcium supplements. Osteomalacia should be diagnosed, and its treatment monitored, by a doctor. In people of any age, vitamin D deficiency causes abnormal bone formation. It occurs more commonly following winter, owing to restricted sunlight exposure during that season. Living in an area with a lot of atmospheric pollution, which can block the sun's ultraviolet rays, also appears to increase the risk of vitamin D deficiency.1
Vitamin D deficiency is more common in strict vegetarians (who avoid vitamin D-fortified dairy foods), dark-skinned people,2 alcoholics, and people with liver or kidney disease. People with liver and kidney disease can make vitamin D but cannot activate it.
Vitamin D deficiency is more common in people suffering from intestinal malabsorption, which may have occurred following previous intestinal surgeries, or from celiac disease.3 People with insufficient pancreatic function (e.g., those with pancreatitis or cystic fibrosis) tend to be deficient in vitamin D. Vitamin D deficiency is also common in individuals with hyperthyroidism (Graves' disease), particularly women.4
In children, vitamin D deficiency is called rickets and causes a bowing of bones not seen in adults with vitamin D deficiency. Vitamin D deficiency is common among people with hyperparathyroidism, a condition in which the parathyroid gland is overactive. In a study of 124 people with mild hyperparathyroidism, vitamin D levels were below normal in 7% of them and suboptimal in 53% of them.5 Vitamin D deficiency is also common in men with advanced prostate cancer. In one study, 44% of 16 men with advanced prostate cancer had decreased blood levels of vitamin D.6
One in seven adults has been reported to be deficient in vitamin D.7 In one study, 42% of hospitalized patients under age 65 were reported to be vitamin D deficient.8 In this same study, 37% of the people were found to be deficient in vitamin D, despite the fact they were eating the currently recommended amount of this nutrient. Vitamin D deficiency is particularly common among the elderly. Age-related decline in vitamin D status may be due to reduced absorption, transport, or liver metabolism of vitamin D.9
How much is usually taken?
People who get plenty of sun exposure do not require supplemental vitamin D, since sunlight increases vitamin D synthesis when it strikes bare skin. Although the recommended dietary allowance for vitamin D is 200 IU per day for adults, there is some evidence that elderly people need 800 to 1,000 IU per day for maximum effects on preserving bone density and preventing fractures.10 11 12 13 Sun-deprived people should take no less than 600 IU per day and ideally around 1,000 IU per day.14 15
Are there any side effects or interactions?
People with hyperparathyroidism should not take vitamin D without consulting a physician. People with sarcoidosis should not supplement with vitamin D, unless a doctor has determined that their calcium levels are not elevated. Too much vitamin D taken for long periods of time may lead to headaches, weight loss, and kidney stones. Rarely, excessive vitamin D may even lead to deafness, blindness, increased thirst, increased urination, diarrhea, irritability, children’s failure to gain weight, or death.
Most people take 400 IU per day, a safe amount for adults. Some researchers believe that amounts up to 10,000 IU per day are safe for the average healthy adult, although adverse effects may occur even at lower levels among people with hypersensitivity to vitamin D (e.g. hyperparathyroidism).16 In fact, of all published cases of vitamin D toxicity for which a vitamin D amount is known, only one occurred at a level of intake under 40,000 IU per day.17 Nevertheless, people wishing to take more than 1,000 IU per day for long periods of time should consult a physician. People should remember the total daily intake of vitamin D includes vitamin D from fortified milk and other fortified foods, cod liver oil, supplements that contain vitamin D, and sunlight. People who receive adequate sunlight exposure do not need as much vitamin D in their diet as do people who receive minimal sunlight exposure.
Vitamin D increases both calcium and phosphorus absorption and has also been reported to increase absorption of aluminum. Increased blood levels of calcium (which may be a marker for vitamin D status) have been linked to heart disease.18 Some,19 but not all,20 research suggests that vitamin D may slightly raise blood levels of cholesterol in humans.
Drug Interactions
Certain medicines interact with vitamin D: Some interactions may increase the need for vitamin D (+), other interactions may be negative (-) and indicate vitamin D should not be taken without first speaking with your physician or pharmacist, others may require further explanation (?). Refer to the individual drug article for specific details about an interaction.
Note: The following list only includes the generic or class name of a medicine. To find a specific brand name, use the Medicines index.
Allopurinol (?)
Anticonvulsants (+)
Bile Acid Sequestrants (+)
Cimetidine (+)
Colestipol (+)
Estradiol (?)
Estrogens (Combined) (+) (-)
Flurbiprofen (+)
Gabapentin (+)
Heparin (+)
Hydroxychloroquine (+)
Indapamide (+)
Isoniazid (+)
Medroxyprogesterone (?)
Mineral Oil (+)
Neomycin (+)
Oral Corticosteroids (+)
Orlistat (+)
Phenobarbital (+)
Sodium Fluoride (+)
Thiazide Diuretics (?)
Valproic Acid (+)
Verapamil (-)
Warfarin (-)
Certain medicines interact with vitamin D: Some interactions may increase the need for vitamin D (+), other interactions may be negative (-) and indicate vitamin D should not be taken without first speaking with your physician or pharmacist, others may require further explanation (?). Refer to the individual drug article for specific details about an interaction.
Note: The following list only includes the generic or class name of a medicine. To find a specific brand name, use the Medicines index.
Allopurinol (?)
Anticonvulsants (+)
Bile Acid Sequestrants (+)
Cimetidine (+)
Colestipol (+)
Estradiol (?)
Estrogens (Combined) (+) (-)
Flurbiprofen (+)
Gabapentin (+)
Heparin (+)
Hydroxychloroquine (+)
Indapamide (+)
Isoniazid (+)
Medroxyprogesterone (?)
Mineral Oil (+)
Neomycin (+)
Oral Corticosteroids (+)
Orlistat (+)
Phenobarbital (+)
Sodium Fluoride (+)
Thiazide Diuretics (?)
Valproic Acid (+)
Verapamil (-)
Warfarin (-)
Source: www.cncahealth.com