title: Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D.
abstract: Many patients treated for vitamin D deficiency fail to achieve an adequate serum level of 25-hydroxyvitamin D [25(OH)D] despite high doses of ergo- or cholecalciferol. The objective of this study was to determine whether administration of vitamin D supplement with the largest meal of the day would improve absorption and increase serum levels of 25(OH)D. This was a prospective cohort study in an ambulatory tertiary-care referral center. Patients seen at the Cleveland Clinic Foundation Bone Clinic for the treatment of vitamin D deficiency who were not responding to treatment make up the study group. Subjects were instructed to take their usual vitamin D supplement with the largest meal of the day. The main outcome measure was the serum 259(OH)D level after 2 to 3 months. Seventeen patients were analyzed. The mean age (+/-SD) and sex (F/M) ratio were 64.5 +/- 11.0 years and 13 females and 4 males, respectively. The dose of 25(OH)D ranged from 1000 to 50,000 IU daily. The mean baseline serum 25(OH)D level (+/-SD) was 30.5 +/- 4.7 ng/mL (range 21.6 to 38.8 ng/mL). The mean serum 25(OH)D level after diet modification (+/-SD) was 47.2 +/- 10.9 ng/mL (range 34.7 to 74.0 ng/mL, p < .01). Overall, the average serum 25(OH)D level increased by 56.7% +/- 36.7%. A subgroup analysis based on the weekly dose of vitamin D was performed, and a similar trend was observed.Thus it is concluded that taking vitamin D with the largest meal improves absorption and results in about a 50% increase in serum levels of 25(OH)D levels achieved. Similar increases were observed in a wide range of vitamin D doses taken for a variety of medical conditions.
authors.affiliation: Department of Endocrinology, Diabetes, and Metabolism, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: Guy B
authors.initials: GB
authors.lastname: Mulligan
authors.forename: Angelo
authors.initials: A
authors.lastname: Licata
mesh_terms: D000042:Absorption; D000284:Administration, Oral; D000368:Aged; D015331:Cohort Studies; D019587:Dietary Supplements; D004334:Drug Administration Schedule; D005260:Female; D005502:Food; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D014808:Vitamin D Deficiency / Q000188:drug therapy*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D