Decoding Nutrition: How Biomarkers Reveal What We Eat

Knowing what we eat is crucial for maintaining good health, but accurately recording dietary intake can be challenging. People often forget foods they consumed, misjudge portion sizes, or unintentionally report inaccurately. This is where intake biomarkers come in. These are measurable compounds found in the body such as in blood, urine, or other tissues that provide objective evidence of recent food or nutrient consumption. When combined with traditional dietary surveys, biomarkers help researchers and clinicians obtain a more precise picture of nutrition, link eating patterns to health outcomes, and support personalised dietary recommendations.

Q1. What is a nutritional biomarker?

A nutritional or intake biomarker is a substance in the body that can be measured to provide an objective indication of dietary intake. For example, after consuming a specific food or nutrient, the body may produce or metabolise certain compounds. Scientists can measure these compounds in blood, urine, or other samples and use them to estimate what was eaten [1,2].

Q2. Why are biomarkers important for health and nutrition?

Traditional methods like food diaries or questionnaires rely on memory and honesty, which can introduce errors. Biomarkers provide an objective way to confirm what someone has consumed. This allows researchers and clinicians to identify nutrient deficiencies or excesses, link diet to conditions such as heart disease or diabetes, and tailor nutrition guidance more accurately [1,3].

Q3. How are biomarkers measured?

Biological samples commonly blood, urine, or occasionally hair or fat tissue are collected and analysed using advanced laboratory techniques like mass spectrometry or chromatography. These methods detect and quantify metabolites or molecules associated with specific foods or nutrients. Proper sample handling, lab protocols, and careful interpretation are critical for reliable results [4,5].

Q4. What factors influence biomarker accuracy?

Several variables can affect biomarker levels: age, sex, metabolism, genetics, medications, underlying health conditions, recent meals, sample collection and storage methods, and lifestyle factors such as smoking or physical activity. Consequently, interpreting biomarkers is more complex than reading a single value [5,6].

Q5. Can biomarkers completely replace dietary surveys?

Not yet. Biomarkers are a powerful complement to self-reported intake but cannot capture all aspects of diet. Some foods and nutrients lack reliable biomarkers, many biomarkers reflect only recent intake, and testing can be expensive or technically demanding. The best approach combines biomarkers with traditional surveys to achieve a comprehensive dietary assessment [1,7].

Q6. Are biomarkers available for all foods and nutrients?

No. While biomarkers exist for several foods and nutrients, many items particularly highly processed foods or those without unique metabolic signatures still lack reliable markers [2,8].

Q7. How are biomarkers used in research and public health?

Biomarkers enhance population-level monitoring of nutrient intake, reducing reliance on self-reports. In research, they improve diet-disease associations, validate dietary interventions, and may enable more personalised nutrition advice based on individual biomarker profiles [1,6].

Q8. What are the main limitations of using intake biomarkers?

Limitations include cost and technical complexity, short-term reflection of intake, incomplete coverage of foods/nutrients, individual variability, strict sample handling requirements, and influences from non-dietary factors like disease or metabolism [5,2].

Q9. What are emerging trends in this field?

Cutting-edge approaches like metabolomics and lipidomics are identifying new candidate biomarkers. Multi-biomarker panels are improving dietary assessments, while wearable sensors and AI tools may integrate lifestyle and biomarker data. Advances in cost and throughput are making biomarker testing increasingly accessible [1,3,6].

Q10. What’s the key takeaway?

Intake biomarkers are a valuable tool in nutrition science. They provide objective evidence of dietary intake, complement traditional methods, and strengthen links between diet and health outcomes. While not yet perfect coverage is incomplete, and testing remains complex they are becoming increasingly useful thanks to methodological and technological advances [7,8,9].

References.

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Maruvada P, Lampe JW, Wishart DS, Barupal D, Chester DN, Dodd D, et al. Perspective: Dietary biomarkers of intake and exposure—exploration with omics approaches. Adv Nutr. 2020;11(2):200-215. https://doi.org/10.1093/advances/nmz075
Praticò G, Gao Q, Scalbert A, Vergères G, Kolehmainen M, Manach C, et al. Guidelines for Biomarker of Food Intake Reviews (BFIRev): how to conduct an extensive literature search for biomarker of food intake discovery. Genes Nutr. 2018;13:3. https://doi.org/10.1186/s12263-018-0592-8
Dragsted LO, Gao Q, Scalbert A, Vergères G, Kolehmainen M, Manach C, et al. Validation of biomarkers of food intake—critical assessment of candidate biomarkers. Genes Nutr. 2018;13:14. https://doi.org/10.1186/s12263-018-0603-9
Vázquez-Manjarrez N, Ulaszewska M, Garcia-Aloy M, et al. Biomarkers of intake for tropical fruits. Genes Nutr. 2020;15:11. https://doi.org/10.1186/s12263-020-00670-4
Perelman SA, Patel TS, Khoury MJ, et al. A scoping review of nutritional biomarkers associated with food security. Nutrients. 2023;15(16):3576. https://doi.org/10.3390/nu15163576
McNamara AE, Walton J, Flynn A, Nugent AP, McNulty BA, Brennan L. The potential of multi-biomarker panels in nutrition research: total fruit intake as an example. Front Nutr. 2021;7:577720. https://doi.org/10.3389/fnut.2020.577720
“Exhaustive Search of Dietary Intake Biomarkers as Objective Tools for Personalized Nutrimetabolomics and Precision Nutrition Implementation.” Nutr Rev. 2024;83(5):925-933. https://doi.org/10.1093/nutrit/7781440