Bachelor of Health Science (BHS) Degree Practice Exam 2025 - Free BHS Practice Questions and Study Guide

A decrease in erythrocytes, or red blood cells, is most likely to occur in someone who has a lack of dietary iron. Iron is a crucial component in the production of hemoglobin, the protein in red blood cells responsible for transporting oxygen. When dietary iron intake is insufficient, the body struggles to produce adequate amounts of hemoglobin, leading to a reduction in the number of erythrocytes. This can result in iron deficiency anemia, a condition characterized by fatigue, weakness, and decreased oxygen delivery to tissues.

Erythrocytes are specifically affected because they are directly reliant on iron for their formation and functionality. In contrast, thrombocytes (platelets), leukocytes (white blood cells), and plasma levels may not show significant changes solely due to iron deficiency. Thrombocytes and leukocytes have different functions and production pathways that are not directly related to iron levels, while plasma is primarily composed of water, electrolytes, proteins, and other substances rather than being directly influenced by iron availability. Therefore, a lack of dietary iron primarily impacts the production of erythrocytes.