Transcript Biomarkers
University of Turku
Department of Biochemistry
Jukka-Pekka Suomela
Biomarkers
Biomarkers
…a biochemical indicator of dietary intake/nutritional status
(recent or long term)
can be used to complement/replace methods of dietary intake
measurements
…or an index of nutrient metabolism
…or a marker of the biological consequences of dietary
intake
Biomarkers
Diplock et al. Scientific concepts of functional foods in Europe:
Consensus document.
British Journal of Nutrition 1999; 81: S1-S27.
Does a biomarker correlate with
nutrient intake?
Nutrient itself (e.g. fat-soluble (storage) vs. water-soluble
vitamins)
Genetic factors
Variation in life style and physiological factors
Nutrient intake related factors
Sample type, taking and handling of samples
Analytical methods
Example: vitamin A
Retinol concentration in the serum does not reflect the intake
because the concentration is regulated by retinol storages and
carrier protein levels in the liver
Beta-carotene in serum is a fair indicator of the intake of
vitamin A
Sample types
Whole blood
Plasma/serum
Blood cells
Lipoproteins
Urine
Feces
Hair
Nails
Tissue sample, e.g. fat biopsy
Collection and handling of samples
Fasting/postprandial specimen
Time of sample collection, possible time points
Instruments for sample collection
Sample handling
Marking and coding of the samples
Storage (temperature, timeperiod)
Analytical methods
Quality assurance is important
Validity and relevance
Need for validation of the measurement techniques
Information on sensitivity, specificity, and reproducibility
needed
Biological relevance: biomarkers need to be clearly linked to
the phenomena involved in the biological process being
studied
Genes and diet
Jenab M. et al. Hum Genet 125: 507-525
Genes and diet
Genetic variation, gene–diet/nutrient ineractions and gene–
gene interactions individual differences in response to diet
and in the measurable level of the biomarker
nutrigenetics: study of how genetic disposition affects
response to diet and its components
nutrigenomics: study of how diet influences gene
transcription, protein expression and metabolism
Utilization of biomarkers and
search for novel ones
E.g. links between fruits/vegetables and cancer is not strong –
true or caused by errors in measurement?
Should biomarkers be utilized more?
Novel biomarkers are needed
Profiling of novel biomarkers
”omics” as a comprehensive approach
Metabonomics: metabolic response to biological, genetic,
environmental or dietary stimuli are measured
linkages between genes, diet, lifestyle and health
e.g. utilization of metabolic profiles to measure dietary intake,
dietary changes, or the efficiency of dietary interventions
certain ”metabonomic profiles” as biomarkers?
Metabolomics: comprehensive analysis of all measurable
metabolite concentrations under a given set of conditions
also: transcriptomics, proteomics, lipidomics…
Profiling of novel biomarkers
Biomarkers
References
Diplock et al. Scientific concepts of functional foods in Europe: Consensus document.
British Journal of Nutrition 1999; 81: S1-S27.
Jenab M. et al. Biomarkers in nutritional epidemiology: applications, needs and new
horizons. Hum Genet 2009; 125: 507-525.