Appetite Regulation, Bone Health, Cardiometabolic Health, Muscle Function
Conditions
Keywords
Child Nutrition, Dietary recommendations, Milk protein, Vitamin D, Bone mineral density, Muscle strength, Immune defence
Brief summary
The purpose of D-pro is to investigate the combined and separate effects of milk protein and vitamin D on bone health, growth, muscle function, body composition and cardiometabolic health in 6-8-year-old children.
Detailed description
The D-pro study investigates the effects of high or medium intakes of milk protein, and vitamin D supplements or placebo, in healthy 6-8 year-old Danish children. The study is a 2×2-factorial randomized controlled trial with 4 study arms. The subjects will be randomly allocated to receive yoghurt products with either high or medium protein content (300g/day, 6 days/week) and to receive tablets with either vitamin D (20 μg/day) or placebo for 24 weeks. Measurements and biological sampling will be performed at baseline and at the end of the intervention. The primary outcome will be bone mineral density (BMD). The investigators will also measure effects on children's muscle function, cardiometabolic health, body composition, growth and growth factors, nutrient status, immune defence and risk of acute respiratory tract infections, as well as appetite hormones. The investigators will also assess potential sex-specific effects and the potential modifying effect of genotype.
Interventions
DIETARY_SUPPLEMENTMilk Protein (high)
High protein yoghurt which contains approx. 10 g protein per 100 g. Participants will be asked to consume 300 g (=3 dl) 6 days a week.
DIETARY_SUPPLEMENTVitamin D
One daily tablet containing 20 μg of vitamin D3, cholecalciferol.
DIETARY_SUPPLEMENTMilk Protein (medium)
Ordinary yoghurt containing approx. 3.3 g protein per 100 g. Participants will be asked to consume 300 g (=3 dl) 6 days a week.
Sponsors
University of Aarhus
Arla Foods
Arla Foods Ingredients
University of Copenhagen
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
D-pro will be double-blinded in respect to D vitamin supplementation or placebo, whereas the allocation of yoghurt with high versus medium milk protein content will not be blinded.
Eligibility
Sex/Gender
ALL
Age
6 Years to 8 Years
Healthy volunteers
Yes
Inclusion criteria
Children must: * Be 6-8 years of age at the start of the intervention * Be healthy * Have a frequent intake of milk and yoghurt products, corresponding to at least ¼ liter a day * Like yoghurt and high protein yoghurt (skyr) * Be of white, Danish or European origin Moreover: * The family must not be planning a winter vacation south of a latitude of 50° North * The child must speak and understand Danish in order to understand the study procedures * At least one parent must read, speak and write Danish
Exclusion criteria
* Known or suspected allergy or intolerance to milk or milk components * Chronic illness or disease that may affect study outcomes * Chronic intake of medicine that may affect study outcomes * Use of vitamin D-containing supplements \>3 days/week the 2 last months and use of any vitamin D-containing supplements the last 1 month before intervention start * Concomitant participation in other studies involving dietary supplements or blood sampling * Living in a household with another participating child
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Bone Mineral Density (BMD) | 24 weeks | Measured by dual energy x-ray absorptiometry (DXA) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Insulin | 24 weeks | by fasting blood sample |
| Insulin-like growth factor-binding protein 3 (IGFBP-3) | 24 weeks | by fasting blood sample |
| Serum calcium | 24 weeks | by fasting blood sample |
| Osteocalcin | 24 weeks | by fasting blood sample |
| Parathyroid hormone (PTH) | 24 weeks | by fasting blood sample |
| Bone-specific alkaline phosphatase | 24 weeks | by fasting blood sample |
| C-terminal telopeptide of type 1 collagen in serum (s-CTX) | 24 weeks | by fasting blood sample |
| Maximal leg press strength | 24 weeks | Measured by isometric leg press |
| Maximal jumping height | 24 weeks | Measured by squat jump with linear encoder |
| Maximal jumping length | 24 weeks | Measured by standing long jump |
| Maximal grip strength | 24 weeks | Measured by hand grip dynamometer |
| Muscle endurance | 24 weeks | Measured by 30 sec. sit-to-stand |
| Blood pressure | 24 weeks | — |
| Hemoglobin A1c (HbA1c) | 24 weeks | by fasting blood sample |
| Glucose | 24 weeks | by fasting blood sample |
| Total cholesterol | 24 weeks | by fasting blood sample |
| High density lipoprotein cholesterol (HDL cholesterol) | 24 weeks | by fasting blood sample |
| Low density lipoprotein cholesterol (LDL cholesterol) | 24 weeks | by fasting blood sample |
| Triacylglycerol (TG) | 24 weeks | by fasting blood sample |
| Bone Mineral Content (BMC) | 24 weeks | by DXA |
| Fat mass index | 24 weeks | by DXA |
| Fat free mass index | 24 weeks | by DXA |
| Bone area | 24 weeks | by DXA |
| Height | 24 weeks | by stadiometer |
| Waist circumference | 24 weeks | — |
| Insulin-like Growth Factor 1 (IGF-1) | 24 weeks | by fasting blood sample |
Other
| Measure | Time frame | Description |
|---|---|---|
| Respiratory tract infections | 24 weeks | by questionnaires |
| Dietary intake | 24 weeks | By 4-day dietary record |
| Physical activity | 24 weeks | by accelerometry |
| C-peptide | 24 weeks | by fasting blood sample |
| Vitamin D binding protein | 24 weeks | by fasting blood sample |
| Serum 25(OH) vitamin D | 24 weeks | by fasting blood sample |
| 1,25(OH)2vitamin D | 24 weeks | by fasting blood sample |
| Urea | 24 weeks | by fasting blood sample |
| Interleukin-6 (IL-6) | 24 weeks | by fasting blood sample |
| Interleukin-1β (IL-1β) | 24 weeks | by fasting blood sample |
| Tumor necrosis factor a (TNF-a) | 24 weeks | by fasting blood sample |
| Leptin | 24 weeks | by fasting blood sample |
| Adiponectin | 24 weeks | by fasting blood sample |
| High sensitivity C-reactive protein (hsCRP) | 24 weeks | by fasting blood sample |
| Immune cell counts | 24 weeks | by fasting blood sample |
| Immuno-active peptides in nasal fluid | 24 weeks | by nasal fluid sample |
| Immuno-active peptides in blood | 24 weeks | by fasting blood sample |
| Vitamin D and calcium intake | 24 weeks | By food frequency questionnaire |
Countries
Denmark
Outcome results
None listed