An investigation of the dietary requirements for vitamin D

Completed

Conditions: Dietary vitamin D intake and status
Nutritional, Metabolic, Endocrine
Dietary intake

Registration Number: ISRCTN20236112

Lead Sponsor: Food Standards Agency (UK)

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Completed

Sex: All

Target Recruitment: 480

Inclusion Criteria

1. Consenting adult men and women
2. Aged 20 - 85 years
3. In general good health

Exclusion Criteria

1. Severe medical illness
2. Hypercalcaemia
3. Known intestinal malabsorption syndrome
4. Excessive alcohol use
5. Those who took medications known to interfere with vitamin D metabolism
6. Pregnancy or planning to become pregnant during the six months of the intervention
7. Those taking high dose vitamin D-containing supplements for three months before initiation of study
8. Those who over the six-month course of intervention are planning a winter vacation to a location at which either the altitude or the latitude would be predicted to result in significant cutaneous vitamin D synthesis from solar radiation (e.g., a mountain ski resort or a winter sun coastal resort)

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
1. Serum 25 hydroxyvitamin D concentrations<br>2. Serum parathyroid hormone concentrations<br>3. Serum calcium concentrations<br>4. Dietary calcium and vitamin D intakes (from four-day food diary and food frequency questionnaire)

Secondary Outcome Measures

Name	Time	Method
1. Bone mineral density (from dual energy x-ray absorptiometry [DXA] scan of spine, hip and whole body)<br>2. Body composition measurements<br>3. Immune markers<br>4. Bone turnover markers