The use of GMP in the dietary management of PKU
Research type
Research Study
Full title
The nutritional and biochemical effect of Glycomacropeptide (GMP) when used as the primary protein source in protein substitute for Phenylketonuria (PKU)
IRAS ID
129497
Contact name
Anita MacDonald
Contact email
Sponsor organisation
Vitaflo International Ltd
Duration of Study in the UK
3 years, 0 months, 0 days
Research summary
Patients with phenylketonuria (PKU) require a protein substitute free from the amino acid phenylalanine. Glycomacropeptide (GMP), a whole protein by-product of cheese production, is naturally low in phenylalanine. Whole protein has physiological benefits compared with synthetic L-amino acid mixtures currently used in protein substitutes for phenylketonuria (PKU), as the latter result in higher and more rapid rises and falls in plasma amino acid levels.
In this open, observational study, the aim is to investigate the effect of a new GMP based protein substitute on nutritional, biochemical and bone density parameters in 30 subjects compared with 20 control subjects taking L-amino acid supplements from from 2 centres. The study has 2 parts. Part 1: at baseline, 3 months and 6 months the following will be collected: growth (height, weight, BMI), acceptability questionnaire, adherence and tolerance of protein substitute, 3-day diet diary and food frequency questionnaire. At baseline and 6 months bloods will be taken: plasma amino acids, carnitine, fasting blood micronutrients (zinc, plasma selenium and glutathione peroxidase, alkaline phosphatase, calcium, phosphorus, magnesium, 1, 25-hydroxyvitamin D, plasma MMA, total homocysteine, iron, ferritin, haemoglobin, vitamin B12, MCV, CRP, total protein). Part 2: biochemical bone turnover markers, growth (height, weight, BMI), adherence, 3-day diet diary and food frequency questionnaire will be assessed (at 0,6,12 & 36 months), pubertal assessment at 0, 12 and 36 months and a DXA bone density scan at 0 and 36 months. Usual weekly fasting finger prick phenylalanine and tyrosine concentrations will be collected at home. Participants will be required to visit the hospital on 4 occasions for Part 1 (once for initial assessment, then at 0,3 & 6 months) and an additional 2 visits for Part 2 (0 & 6 months as in Part 1, plus 12 months and 36 months).
REC name
West Midlands - South Birmingham Research Ethics Committee
REC reference
13/WM/0435
Date of REC Opinion
20 Dec 2013
REC opinion
Favourable Opinion