Practical Training – BGZ2024
Biomarkers of protein intake
Practical protein breakdown
Student name
Student number
BGZ2024 – Food for life
Maastricht University
1
, 1) What is the aim of the practical training?
The most important thing about this training about protein intake is that it provides a clear
picture of the intake of proteins and the urinary output of proteins. By calculating the intake
of food over 3 days, a view of the macronutrients ingested is created. The nitrogen
concentration in urine can then be calculated for these macronutrients (in this case the
proteins), as well as the energy content of urea. These are very important biomarkers to
measure the protein intake from the past days. With this data the breakdown of the body can
be calculated. It becomes clear whether there is a correct balance between intake and output
and whether the values meet the reference values. It also becomes more clear about what
happens with the proteins in the body and what the correlation is between the variables. For
me, the aim of the training was what happens to your proteins after eating these
macronutrients, how much there will be secreted from the intake, which biomarkers are
important for the measurement and which measuring instruments to use.
What I also learned about the practical training, after recording my habitual dietary protein
for 3 days, I am a lot more aware about my food intake, especially my protein intake.
2) Briefly describe the used methodologies
Food diary
For the food diary I used the app 'Personal Body Plan'. I am tracking my nutrition every day.
The app indicates how many carbohydrates, proteins, fats, fibers and kilocalories are in each
meal, the app was very useful for this assignment
Biochemical measurement of urea
I used 10 μL from my collected urine from the past 24 hours, and diluted this in 90 μL
distilled water (1:10 collected urine from the past 24 hours, 9:10 distilled water)
I have made 6 more cuvettes, 3 times the diluted urine in duplicate. The cuvettes are
filled with:
1. 1000 μL distilled water
2. 20 μL distilled water, 1000 μL Reagent (B)
3. 20 μL distilled water, 1000 μL Reagent (B)
4. 20 μL standard (A), 1000 μL Reagent (B)
5. 20 μL standard (A), 1000 μL Reagent (B)
6. 20 μL urine (1:10), 1000 μL Reagent (B)
7. 20 μL urine (1:10), 1000 μL Reagent (B)
The reagent (B) has been added to the cuvettes later.
To adjust the spectrophotometer to zero, I have prepared one cuvette with only distilled
water. The extinction 0,000 nm
Before the reagent (B) has to be added, we have made an efficient time schedule, to
measure to extinction of the cuvettes, because we had to work very fast. After that, the
1000 μL reagent (B) has been added very fast to each duplicated cuvette and have been
mixed thoroughly with a stirrer (between the cuvettes, the stirrer has to be clean to
prevent bias). After that, the extinction of each cuvette has been measured by the
spectrophotometer (wavelength 340 nm).
After the measurements, we have calculated different values which I provide more
information about in the following questions
3) Include Tables 1 and 2 from the individual 3-day food dairy. (4 pt)
2
Biomarkers of protein intake
Practical protein breakdown
Student name
Student number
BGZ2024 – Food for life
Maastricht University
1
, 1) What is the aim of the practical training?
The most important thing about this training about protein intake is that it provides a clear
picture of the intake of proteins and the urinary output of proteins. By calculating the intake
of food over 3 days, a view of the macronutrients ingested is created. The nitrogen
concentration in urine can then be calculated for these macronutrients (in this case the
proteins), as well as the energy content of urea. These are very important biomarkers to
measure the protein intake from the past days. With this data the breakdown of the body can
be calculated. It becomes clear whether there is a correct balance between intake and output
and whether the values meet the reference values. It also becomes more clear about what
happens with the proteins in the body and what the correlation is between the variables. For
me, the aim of the training was what happens to your proteins after eating these
macronutrients, how much there will be secreted from the intake, which biomarkers are
important for the measurement and which measuring instruments to use.
What I also learned about the practical training, after recording my habitual dietary protein
for 3 days, I am a lot more aware about my food intake, especially my protein intake.
2) Briefly describe the used methodologies
Food diary
For the food diary I used the app 'Personal Body Plan'. I am tracking my nutrition every day.
The app indicates how many carbohydrates, proteins, fats, fibers and kilocalories are in each
meal, the app was very useful for this assignment
Biochemical measurement of urea
I used 10 μL from my collected urine from the past 24 hours, and diluted this in 90 μL
distilled water (1:10 collected urine from the past 24 hours, 9:10 distilled water)
I have made 6 more cuvettes, 3 times the diluted urine in duplicate. The cuvettes are
filled with:
1. 1000 μL distilled water
2. 20 μL distilled water, 1000 μL Reagent (B)
3. 20 μL distilled water, 1000 μL Reagent (B)
4. 20 μL standard (A), 1000 μL Reagent (B)
5. 20 μL standard (A), 1000 μL Reagent (B)
6. 20 μL urine (1:10), 1000 μL Reagent (B)
7. 20 μL urine (1:10), 1000 μL Reagent (B)
The reagent (B) has been added to the cuvettes later.
To adjust the spectrophotometer to zero, I have prepared one cuvette with only distilled
water. The extinction 0,000 nm
Before the reagent (B) has to be added, we have made an efficient time schedule, to
measure to extinction of the cuvettes, because we had to work very fast. After that, the
1000 μL reagent (B) has been added very fast to each duplicated cuvette and have been
mixed thoroughly with a stirrer (between the cuvettes, the stirrer has to be clean to
prevent bias). After that, the extinction of each cuvette has been measured by the
spectrophotometer (wavelength 340 nm).
After the measurements, we have calculated different values which I provide more
information about in the following questions
3) Include Tables 1 and 2 from the individual 3-day food dairy. (4 pt)
2
