Vitamins: Overview

Question 1

What does history tell us about the discovery of Vitamins?

Answer 1

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• Vitamins are non-caloric essential nutrients that are necessary in very small amounts for specific metabolic control and disease prevention
• Organic
• They do NOT provide energy
• Essential (must be obtained from food)
  
  • Some produced by bacteria in the gut (K)
• Certain health problems are related to inadequate or excess vitamin intake

Question 2

Compare and contrast the characteristics of the water-soluble and fat-soluble vitamins

Answer 2

Water-Soluble: 
- Absorbed in the blood
- Transported freely
- They circulate freely, aren't stored
- Readily excreted
Fat-Soluble:
- Absorbed in the lymph
- Transported by carriers
- Stored in fat tissue
- Less readily excreted

Question 3

What are precursors? What do they have to do with vitamins?

Answer 3

Provitamins

• Used when it is desirable to label a substance with little or no vitamin activity, but which can be converted to an active form by normal metabolic processes
• Consumed in the inactive form&raquo_space; become active in the body

Question 4

What are coenzymes? What do they have to do with vitamins?

Answer 4

Associate with certain enzymes; cofactors that are needed to help the enzyme perform its function in the body

Question 5

Discuss bioavailability

Answer 5

Rate and extent to which a nutrient is absorbed and used
- Not everything that is seen on a food label will be absorbed
SO, amount of vitamin available in food does NOT just depend on quality of vitamin in food (several other activation factors that play a role)

Question 6

What factors can destroy vitamins in food and why? What can be done to minimize these nutrient losses?

Answer 6

Light, oxidation, cooking, storage
SO:
- Refrigerate, use airtight containers or wrappers, cook in small amounts of water, avoid high temperatures and long cooking times

Question 7

Identify circumstances when vitamin-mineral supplementation might be necessary

Answer 7

Elderly people, vegetarians, people with certain food allergies, pregnant women,