Dietary biomarkers are biological indicators that reflect nutrient intake, dietary exposure, or metabolism within the body, offering an objective measure of diet quality. Blood levels of vitamins, minerals, and fatty acids can indicate recent nutrient intake, while urinary biomarkers can reflect specific dietary components and their metabolism. In nutritional research, biomarkers are valuable for assessing adherence to dietary interventions and understanding diet-disease relationships. By accurately measuring these indicators, researchers gain insights into how diet affects disease risk, metabolic health, and other outcomes. Dietary biomarkers help improve precision in nutritional assessments, advancing our understanding of nutrition’s role in health and disease prevention.