Which food groups are included in the United States Department of Agriculture (USDA) food patterns?

A. Hemoglobin is the oxygen-carrying protein in red blood cells. Its production depends on iron and vitamins such as B6, B12, and folate, but vitamin C does not directly synthesize hemoglobin. Although vitamin C can enhance iron absorption, it is not a component of hemoglobin formation itself.

B. Albumin is a major plasma protein synthesized in the liver. It helps maintain blood osmotic pressure, transports hormones, fatty acids, and drugs, and contributes to overall fluid balance. Vitamin C is not required for albumin production, so this is not the correct answer.

C. Iodine is an essential trace element used to produce thyroid hormones, not a protein. Vitamin C has no role in iodine metabolism or thyroid hormone synthesis.

D. Collagen is a structural protein found throughout the body in connective tissues such as skin, tendons, ligaments, cartilage, and blood vessel walls. Vitamin C is a critical cofactor in the enzymatic hydroxylation of proline and lysine residues during collagen synthesis, which stabilizes the triple-helix structure of collagen. Adequate vitamin C ensures strong, healthy connective tissues, proper wound healing, and tissue repair. A deficiency in vitamin C leads to scurvy, characterized by weakened connective tissue, bleeding gums, poor wound healing, joint pain, and easy bruising. Collagen synthesis is therefore the primary way vitamin C helps maintain tissue health.

A. Calcium is the most abundant mineral in the human body. Approximately 99% of the body’s calcium is stored in bones and teeth, providing structural strength and support. The remaining 1% is found in blood, muscle, and other tissues, where it plays a critical role in muscle contraction, nerve transmission, blood clotting, and cellular signaling. Adequate calcium intake throughout life is essential to maintain bone density, prevent osteoporosis, and support overall physiological functions.

B. Fluoride is a trace mineral primarily found in teeth and bones. It helps strengthen tooth enamel and prevent dental caries by making enamel more resistant to acid produced by bacteria. However, fluoride is present in much smaller amounts compared to calcium and does not contribute significantly to skeletal structure. Its primary role is dental protection rather than overall mineral abundance.

C. Iron is essential for oxygen transport in hemoglobin and myoglobin, as well as for various enzymatic reactions in metabolism. Iron deficiency can lead to anemia, fatigue, and impaired immune function. Despite its critical physiological roles, iron is a trace mineral in terms of total body content and is far less abundant than calcium. The majority of iron is stored in hemoglobin within red blood cells, with smaller amounts in the liver and muscle tissues.

D. Zinc is another trace mineral required for numerous enzymatic functions, immune system support, wound healing, DNA synthesis, and growth. It is vital for health but is present in relatively small amounts in the body compared to calcium. Zinc deficiency can cause growth retardation, immune dysfunction, and delayed wound healing, but its total body content is minimal.