Iron-deficiency anemia is a common condition where the body lacks enough iron to produce sufficient hemoglobin, the protein in red blood cells that carries oxygen. Without enough hemoglobin, the body struggles to transport oxygen to vital organs, leading to symptoms like fatigue, weakness, and pale skin. This type of anemia can occur due to various reasons, such as inadequate dietary intake of iron-rich foods, blood loss from menstruation or injury, or absorption issues in the digestive system. Eating foods like spinach, red meat, and beans can help improve iron levels and alleviate symptoms.