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Vitamin D is essential to build and maintain healthy bones throughout life. Calcium, the main element of bone, can be absorbed into the body only when vitamin D is present. Vitamin D and calcium are involved in many body functions, including keeping your immune and nervous systems healthy.
Getting enough vitamin D can help prevent a number of serious health conditions, including those listed below.
Vitamin D is also helpful in the following ways.
You may benefit from taking a vitamin D supplement if the following applies to you.
Foods that contain vitamin D include the following.
Sunlight is a natural source of vitamin D. If you are fair-skinned, 20 to 30 minutes a day in bright sunlight will meet your vitamin D needs. If you are dark-skinned, you need three hours to get the same benefit. Clouds, smog, clothing, sunscreen, and window glass all decrease the amount of vitamin D you get from sunlight.
Vitamin D is included in many multivitamins. It can be found in over-the-counter preparations in strengths from 50 IU to 1,000 IU as softgel capsules, tablets, and liquid. Higher-dose prescription preparations are available. If you have trouble digesting fat, vitamin D injections are also available by prescription.
How to Take It
To prevent disease, adults who do not get regular exposure to bright sunlight should take between 200 IU and 400 IU daily. Discuss your supplement regimen regularly with your health care provider. As with all medications, check with your health care provider before giving vitamin D to a child.
Taking too much vitamin D (more than 1,000 IU daily) can make you very ill. Symptoms include excessive thirst, metal taste, bone pain, tiredness, sore eyes, itching skin, vomiting, diarrhea, a need to urinate, and muscle problems. Getting too much sunlight will not give you too much vitamin D.
Check with your doctor before taking vitamin D if you have high blood calcium or phosphorus levels or if you have a cardiac or kidney disease.
Isoniazid (INH), cholestyramine, antacids, calcium channel blockers, anticonvulsants, and thiazide diuretics all interfere with vitamin D.
INH, a medication used to treat tuberculosis, may raise blood levels of this vitamin.
Cholestyramine, a cholesterol-lowering medication, interferes with the absorption of vitamin D (as well as other fat soluble vitamins).
Calcium-channel blockers (such as verapamil) that are used to treat high blood pressure and heart conditions may interfere with the production of vitamin D by the body. Phenobarbital, phenytoin, and other anticonvulsant medications increase the bodys use of vitamin D.
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