some excerpts from

http://www.ehow.com/about_4571713_vi...eficiency.html

One D vitamin, classified as D2, comes from food, while vitamin D3 is synthesized in the skin when we are exposed to sunlight.

The form of vitamin D we get from our food sources is not readily available for the body's use until it is converted by the liver and kidneys. People with liver, kidney, gallbladder and intestinal disorders may have a difficult time of converting vitamin D to the usable form and are at risk for vitamin D deficiency. Very dark-skinned people such as African Americans are also at risk for vitamin D deficiency as their skin pigment blocks ultraviolet light rays. Those who limit their exposure to the sun through the use of high-SPF sunblocks or who do not venture outdoors for exercise or sport are also at a high risk for vitamin D deficiencies.

Patients who are taking cholesterol-lowering drugs such as statins, antacids, mineral oil and steroids should know that these drugs interfere with the absorption of vitamin D. Thiazide diuretics, such as HCTZ, disrupt the balance between calcium and vitamin D in the body; patients should have a regular metabolic panel to determine the level of vitamin D and calcium in their bodies. Vitamin D should not be taken without calcium; in the absence of the latter, vitamin D pulls calcium from the bones and teeth in order to synthesize with it, resulting in possible breakage.

Sources of Vitamin D include fish liver oils, fatty saltwater fish, dairy products and eggs. Butter, cod liver oil, dandelion greens, shiitake and chanterelle mushrooms, oatmeal, oysters, salmon, sardines, sweet potatoes, tuna and vegetable oil are all wonderful sources of Vitamin D. Herb sources include alfalfa, horsetail, nettle and parsley.
Care should be taken to consume enough vitamin D in the diet and also to spend some time each day getting a little sun. Twenty minutes per day of sunshine is all that is needed for the proper synthesis of vitamin D. Vitamin D is also available as a supplement, but again, this should be taken only with calcium to prevent compromise of bone and muscle strength.

my recipe

boil water and throw in a bunch of parsley simmer 3 minutes, strain. drink the liquid. this will improve liver & gall bladder function and maybe aid the absorption.