Availability of Vitamin D in Orange Juice

This study should provide valuable information about the bioavailability of both vitamin D2 and vitamin D3 formulated in orange juice compared to vitamin D2 and vitamin D3 formulated in a pill and taken with water. It is anticipated based on our previous observation that the vitamin D2 and vitamin D3 in orange juice will be at least 50% more effective in raising the blood levels of 25(OH)D than when taken in pill form.

This study will evaluate the bioavailability and metabolism of vitamin D2 and vitamin D3 in combination in tablet form. The results should provide important information as to whether a physiologic dose of vitamin D2 has a negative effect on circulating levels of 25-hydroxyvitamin D2 [25(OH)D2 ] and on 25-hydroxyvitamin D3 [25(OH)D3]. Results from this study have important implications for expanding the adequate intake (AI) recommendations for vitamin D2 and vitamin D3 for adults.

Inclusion criteria

• Male and female adults of all races ages 18 years and older

Exclusion criteria

• Pregnant and lactating women
• History of chronic severe liver (as defined by liver function test greater than 2 times upper limit of normal)or kidney disease as defined by a serum creatinine >2.5.
• History of taking a daily supplement that contains 400 or more IU vitamin D2 or vitamin D3 within the past month or taking a pharmacologic amount of vitamin D2 or one of the active vitamin D analogs including Zemplar (Paricalcitol), Dovonex (calcipotriol), Hectorol (vitamin D pro hormone)
• Subjects who are taking orally Dilantin or glucocorticoids.
• Exposure to a tanning bed or tanning on a beach for more than eight hours within the past month.
• Subjects who drink more than 2 glasses (16 oz) cups of milk a day.
• Known history of elevated calcium. (> 10.5 mg% (mg/dl))
• History of intestinal malabsorption (i.e. Cystic Fibrosis, Fat malabsorption Syndrome, Crohn's Disease)
• Allergies to orange juice
• Any medical conditions in which it is not advisable to receive one 8 oz. glass of orange juice per day.
• Currently taking, or having taken less than one month prior to start of study, a prescription vitamin D
• Unwilling to consent to this trial