Plain English Summary
Background and study aims
Phosphorus is an essential mineral that is required by every cell in the body for normal function, but high phosphorus levels can lead to cardiovascular (heart) disease. Shift workers have an increased risk of coronary heart disease, suggesting that eating at night may affect how the body uses phosphorus (phosphorus metabolism), but this has not been investigated. The purpose of this study was to investigate the effects of nocturnal eating on phosphorus metabolism.
Who can participate?
Healthy men aged 20-40.
What does the study involve?
Participants were served test meals three times a day (breakfast at 07:30, lunch at 12:30, dinner at either 17:30 or 22:30). Blood and urine samples were collected to assess phosphorus levels until the following morning.
What are the possible benefits and risks of participating?
Participants will find out their health status. There is a risk of side effects from the blood sample collection.
Where is the study run from?
University of Shizuoka (Japan).
When is the study starting and how long is it expected to run for?
July 2013 to January 2015.
Who is funding the study?
Ministry of Education, Culture, Sports, Science and Technology (Japan).
Who is the main contact?
Dr Masae Sakuma
Dr Masae Sakuma
+81 (0)54 264 5596
University hospital Medical Information Network (UMIN)/UMIN000014380
Effect of nocturnal eating on phosphorus excretion in young subjects: a randomized crossover trial
To assess the effects of nocturnal eating on phosphorus metabolism.
The Ethics Committee of the University of Shizuoka, 25/06/2013, ref: University of Shizuoka 25-9
interventional randomized crossover trial
Primary study design
Secondary study design
Randomised cross over trial
Patient information sheet
The subjects were served test meals three times a day (breakfast 07:30 h, lunch 12:30 h, dinner 17:30 or 22:30 h). Blood and urine samples were collected to assess diurnal variation until the following morning.
Primary outcome measure
Serum phosphorus level, measured at baseline (0 hours) and 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 24.0 hours after
Secondary outcome measures
1. Urinary phosphorus excretion, measured at four times over the 24 hours: between 07:30 h to 12:30 h (morning); 12:30 h to 17:30 h (afternoon); 17:30 h to 22:30 h (evening); and 22:30 h to 07:30 h, the following morning (night)
2. Serum parathyroid hormone level, measured at baseline (0 hours) and 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 24.0 hours after
3. Serum FGF23 level, measured at baseline (0 hours) and 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 24.0 hours after
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. 20-40 years old
Target number of participants
Participant exclusion criteria
2. History or medication use for glucose tolerance, renal or hepatic dysfunction
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
University of Shizuoka
Ministry of Education, Culture, Sports, Science and Technology (Japan)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
To be confirmed at a later date
Intention to publish date
Participant level data
Available on request
Basic results (scientific)
2015 results in http://www.ncbi.nlm.nih.gov/pubmed/26450680