Nutritional biomarkers are a type of biomarker that provides objective data on food exposure. A nutritional biomarker can be described as any biological specimen that is an indicator of nutritional status in terms of dietary element intake or metabolism. It might be a biochemical, functional, or clinical indicator of a nutrient's or another dietary constituent's state. Biomarkers, rather than dietary consumption, give a more proximal estimate of nutritional status. In general, a nutritional biomarker is a trait that can be objectively tested in various biological samples and utilised as an indicator of nutritional status in terms of dietary ingredient intake or metabolism. Biomarkers that measure intake of specific foods and dietary components could substantially help nutritional studies aimed at determining compliance with national standards as well as direct connections with illness outcomes. More research is needed to enhance existing biomarkers by accounting for confounding factors, generate novel indicators of specific food intake, and produce cost-effective, noninvasive, fast, and accurate nutritional status measurements.