Biochemistry Lecture 3: Vitamins Overview

Vitamins and Toxicity

• Water-soluble vitamins are readily excreted in the urine, and toxicity is rare.

Fatsoluble Vitamins

• Fat-soluble vitamins are stored in significant quantities in the body's adipose tissue.

Fatsoluble Retinoids

• The main functions of fatsoluble retinoids include regulating genes, differentiating cells, and maintaining epithelial tissues.
• Retinoic acid plays a crucial role in the body by regulating gene expression and promoting cell differentiation.

Vitamin A

• Vitamin A predominates in nature in its beta-carotene form.
• Retinol and carotenes are absorbed in the small intestine.
• The daily requirement of vitamin A for adult males is 900 μg/day and for adult females is 700 μg/day.
• Liver and dairy products are sources that provide three preformed compounds of vitamin A.
• The liver stores retinol when absorbed in the body.

Retina and Vision

• Rod cells in the retina process dim light and peripheral vision.
• The primary function of the optic nerve is to transmit visual information from the eye to the brain.
• Cone cells in the retina are specialized for color and detail vision in bright light.

Vitamin A Requirements

• The Recommended Dietary Allowance (RDA) for adult males is 900 μg/day and for adult females is 700 μg/day.

Vitamin A Precursors

• Lycopene does not serve as a precursor of vitamin A2.

Freshwater Fish

• Freshwater fish are distinguished from other animal sources by containing astaxanthin, a carotenoid pigment.