15 Questions
What are nutritional biomarkers?
Constituents in the blood or urine that can be used to estimate nutrient intake
Which type of validation study using biomarkers is considered the gold standard?
Recovery
What do concentration biomarkers correspond to?
Correspond to but does not reflect total intake
In what situation do replacement biomarkers serve as a proxy for intake?
When it is not possible to capture intake due to limited nutrient databases to assess intake
What is important to appreciate about the time period of exposure reflected by biomarkers in nutritional epidemiology?
It differs from that of dietary intake
What are nutritional biomarkers used to estimate?
nutrient intake or compare nutrient intake to that estimated by dietary assessment
What is an example of a biomarker used in recovery validation studies?
doubly labeled water, urinary nitrogen, urinary potassium
Give an example of a concentration biomarker.
plasma vitamin C or plasma carotenoids
When do replacement biomarkers serve as a proxy for intake?
when it is not possible to capture intake due to limited nutrient databases to assess intake
What is important to appreciate about the time period of exposure reflected by biomarkers in nutritional epidemiology?
that it differs from that of dietary intake
Explain the use of biomarkers in estimating nutrient intake and comparing it to dietary assessment.
Biomarkers in the blood or urine can be used to estimate nutrient intake or compare nutrient intake to that estimated by dietary assessment, providing objective validation of dietary assessments.
What are the three categories of validation studies using biomarkers, and provide an example for each?
The three categories are recovery, concentration, and replacement. Example for recovery: doubly labeled water. Example for concentration: plasma vitamin C. Example for replacement: sodium.
What is the gold standard validation study for biomarkers, and provide an example?
The gold standard validation study is recovery. Example: doubly labeled water.
In what situation do replacement biomarkers serve as a proxy for intake?
Replacement biomarkers serve as a proxy for intake when it is not possible to capture intake due to limited nutrient databases to assess intake.
Why is it important to appreciate the difference in time period of exposure reflected by biomarkers in nutritional epidemiology compared to dietary intake?
It is important to appreciate because the time period of exposure reflected by the biomarker differs from that of dietary intake, which can impact the interpretation of nutritional epidemiology studies.
Study Notes
Nutritional Biomarkers
- Constituents in blood or urine used to estimate nutrient intake or compare to dietary assessment.
- Provide objective validation of dietary assessments, independent of food intake.
Categories of Validation Studies using Biomarkers
- Recovery: Gold standard, example: doubly labeled water, urinary nitrogen, urinary potassium.
- Concentration: Correspond to but do not reflect total intake, example: plasma vitamin C or plasma carotenoids.
- Replacement: Proxy for intake when limited nutrient databases, example: sodium, phytoestrogens, polyphenols or aflatoxin.
Biomarkers in Nutritional Epidemiology
- Time period of exposure reflected by biomarker differs from that of dietary intake.
- Important to appreciate this difference in exposure periods.
Test your knowledge on the use of biomarkers in nutrition with this quiz. Explore the categories of validation studies and understand how biomarkers provide objective validation of dietary assessments.
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