Vitamins and minerals.
Vitamins and minerals are organic and inorganic compounds required for various metabolic processes. They're obtained through diet because the human body cannot synthesize sufficient quantities.
Vitamins
Vitamins are classified as either fat-soluble or water-soluble.
- Fat-soluble vitamins (A, D, E, and K) are absorbed like lipids, forming micelles that are transported to intestinal cells and then incorporated into chylomicrons before entering the lymphatic system and eventually the general circulation.
- Water-soluble vitamins (B and C) generally follow water absorption pathways, often using Na+-dependent cotransport mechanisms. Vitamin B12 is an exception, requiring intrinsic factor secreted by gastric parietal cells for absorption in the ileum.
Minerals
Minerals are essential for numerous physiological functions.
- Calcium, for example, plays a vital role in bone health, muscle contraction, nerve function, and blood clotting.
- Iron is crucial for red blood cell formation (hemoglobin) and oxygen transport.
Recap Questions
- What are the main differences between fat-soluble and water-soluble vitamins?
- Describe the role of intrinsic factor in the absorption of vitamin B12.
- Why is calcium essential for human health?
- What are the potential consequences of vitamin and mineral deficiencies?
- How can you ensure adequate vitamin and mineral intake through a balanced diet?