PURPOSE OF REVIEW: The environmental presence of excess nitrogen poses a significant threat to biodiversity, human health, and climate stability. Conversely, nitrogen deficiency can hinder our ability to sustainably provide sufficient food for the global population. The impact of nitrates and nitrites on human health is intricately tied to their concentrations in water and food sources. The aim of the following article was to summarize the data on the effects of nitrates on health, with particular emphasis on their effect on the thyroid gland. RECENT FINDINGS: Current scientific findings indicate that these compounds can have dual effects, both beneficial and harmful, on health. Dietary nitrates are naturally abundant in fruits and vegetables or can be introduced as additives, notably in processed and cured meats. Nitrate supplementation has shown promise in enhancing physical performance, influencing gut microbiota composition, and increasing short-chain fatty acid production. Studies suggest that nitrate consumption can effectively reduce inflammation and counter the deleterious effects of oxidative stress in the body. However, the addition of nitrites as preservatives may lead to the formation of nitrosamines, known carcinogens that detrimentally impact cardiovascular and metabolic functions. SUMMARY: Excessive nitrite intake from animal sources has been linked to an increased risk of thyroid cancer, particularly among women. Nevertheless, a moderate intake of naturally occurring nitrates from food sources demonstrates potential benefits such as blood pressure regulation, improved vascular endothelial function, and enhanced tissue insulin sensitivity. These positive effects might mitigate risk factors associated with developing complications in thyroid disease and warrant further investigation.