Final answer:
Iron is often the most deficient nutrient among children and adolescents in the US, essential for forming hemoglobin in red blood cells, and can be addressed by a diet rich in iron and vitamin C to aid absorption.
Step-by-step explanation:
Among children and adolescents in the US, iron is often identified as the most deficient nutrient. Iron is essential for the body as it helps in the formation of hemoglobin in red blood cells, which carries oxygen throughout the body. A lack of sufficient iron can lead to conditions like anemia, which is characterized by fatigue and weakness. While other nutrients like calcium, vitamin A, and fiber also play critical roles in children's health and development, iron deficiency is comparatively more common among this demographic. Ensuring a diet that includes iron-rich foods such as leafy greens, beans, meats, and iron-fortified products, along with vitamins like vitamin C that help with iron absorption, is essential in preventing iron deficiency.