Chapter 11: Fat-Soluble Vitamins (A, D, E, K)

Fat-Soluble Vitamins

Vitamins that require bile for digestion and absorption, transport through the lymphatic system, are stored in the liver and adipose tissue, and have a higher risk of toxicity.

Vitamin A

The first fat-soluble vitamin recognized, existing in active forms such as retinol, retinal, and retinoic acid, and essential for vision, cell differentiation, and reproduction.

Beta-Carotene

A precursor to Vitamin A found in plant sources, which can be converted to Vitamin A in the body.

Symptoms of Vitamin A Deficiency

Increased risk of infectious diseases, night blindness, and potential death.

Vitamin A Toxicity

Possible when consuming excess preformed vitamin A from animal sources, supplements, or fortified foods, with children being particularly vulnerable.

Vitamin D

A non-essential nutrient that the body synthesizes from cholesterol with sunlight exposure, playing a role in bone growth and calcium absorption.

Consequences of Vitamin D Deficiency

Can lead to rickets in children, osteomalacia in adults, and osteoporosis, especially in the elderly.

Vitamin E

Includes tocopherols and tocotrienols, with alpha-tocopherol being the only form maintained in the body; acts as an antioxidant.

Vitamin K

Essential for blood clotting and metabolism of bone proteins, with a primary action in activating proteins needed to make blood clots.

Vitamin K Food Sources

Green vegetables such as spinach and kale, as well as certain fruits like avocados and kiwis.