What deficiency is primarily associated with fatigue and weakness due to low levels of hemoglobin?

Low levels of hemoglobin in the blood are most closely linked to iron deficiency. Hemoglobin is an iron-rich protein found in red blood cells that is responsible for transporting oxygen throughout the body. When the body lacks sufficient iron, it cannot produce enough healthy hemoglobin, leading to a condition known as iron deficiency anemia. This results in reduced oxygen delivery to tissues, which can cause symptoms such as fatigue and weakness.

Iron deficiency is particularly prevalent in populations with inadequate dietary intake of iron, including certain groups such as pregnant women, individuals with heavy menstrual bleeding, or those with diets low in meat and other iron-rich foods. By addressing iron deficiency, one can improve hemoglobin levels and alleviate associated fatigue and weakness.

While deficiencies in vitamin D, protein, or magnesium can cause other health issues, they do not specifically cause low hemoglobin levels as directly as iron deficiency does.