Vitamin A

Vitamin A is a fat-soluble vitamin that is essential for maintaining good vision, healthy skin, and a strong immune system. It is also important for growth and development, and plays a crucial role in the function of many organs in the body.

Sources of Vitamin A

Vitamin A can be obtained from both animal and plant sources. Some of the best sources of preformed vitamin A (retinol and its esterified form, retinyl ester) include:

• Liver
• Egg yolks
• Dairy products

Provitamin A carotenoids, such as beta-carotene, are found in fruits and vegetables, including:

• Carrots
• Sweet potatoes
• Spinach
• Kale

Functions of Vitamin A

Vitamin A plays several important roles in the body, including:

• Supporting vision, especially in low light conditions
• Promoting healthy skin and mucous membranes
• Supporting immune function
• Participating in cell differentiation

Deficiency and Toxicity

A deficiency in vitamin A can lead to night blindness, increased susceptibility to infections, and poor growth. On the other hand, excessive intake of vitamin A can lead to toxicity, causing symptoms such as nausea, dizziness, and even liver damage.

Study Guide

1. What are the sources of preformed vitamin A?
2. Which fruits and vegetables are good sources of provitamin A carotenoids?
3. What are the main functions of vitamin A in the body?
4. What are the consequences of vitamin A deficiency?
5. What are the potential risks of excessive vitamin A intake?

Understanding the importance of vitamin A and its sources, as well as the potential risks of deficiency and toxicity, is essential for maintaining a balanced and healthy diet.