Unit 9: The Vitamins

Question 1

explain the concept of dietary patterns.

Answer 1

refer to the complex mixture of many different foods that people eat. A dietary pattern is the sum of thousands of individual substances.

Question 2

define phytochemicals.

Answer 2

an extremely diverse group of substances that share three features: they are organic, they are found in plant foods, and they are not vitamins (i.e., they are not essential) (phyto means “plant”)

Question 3

describe the general characteristics of vitamins

Answer 3

Vitamins are a group of organic compounds essential for the normal functioning of the body. They vary widely in their chemical structures and functions. Many act as coenzymes, helping enzymes in regulating metabolism (e.g., B vitamins). Others act like hormones (e.g., vitamin D) or are antioxidants (e.g., vitamins C and E). Some assist in the formation of bones and tissues (e.g., vitamins A and C). Although much is known about the vitamins, research into their roles and mechanisms of action is ongoing.

Most vitamins cannot be manufactured in the body; they must be obtained solely from food sources. Vitamin A and niacin can be synthesized by the body from dietary precursors; provitamin D can be synthesized under the skin with the help of sunlight.

Question 4

discuss the differences between water- and fat-soluble vitamins regarding the body’s absorption, storage, and excretion

Answer 4

Water-Soluble Vitamins:

-Absorption: Absorbed directly into the bloodstream through the small intestine.
-Storage: Not stored significantly in the body, requiring regular intake.
-Excretion: Excess amounts are eliminated through urine, lower risk of toxicity.

Fat-Soluble Vitamins:

-Absorption: Absorbed with dietary fats and bile salts, enter lymphatic system.
-Storage: Stored in body’s fat tissues and organs, potential for toxicity with excessive intake.
-Excretion: Excreted slowly through bile and feces, higher risk of toxicity due to slower elimination.

Question 5

discuss the differences between water- and fat-soluble vitamins regarding potential toxicity to the body

Answer 5

Water-Soluble Vitamins:

-Toxicity Risk: Low risk due to rapid excretion in urine.
-Excess Intake: Excessive consumption rarely leads to toxic levels.

Fat-Soluble Vitamins:

-Toxicity Risk: Higher risk due to slower excretion and storage in the body.
-Excess Intake: Overconsumption can lead to toxic accumulation over time.

Question 6

discuss the differences between water- and fat-soluble vitamins regarding retention in food through processing and storage.

Answer 6

Water-Soluble Vitamins:

-Retention: Sensitive to heat and water; can be lost during cooking and processing.
-Storage: Not significantly affected by storage.

Fat-Soluble Vitamins:

-Retention: More stable during cooking; less affected by heat and water.
-Storage: Susceptible to degradation during long storage periods.

Question 7

name the fat-soluble vitamins

Answer 7

Vitamins A, D, E, K

Question 8

name the water-soluble vitamins

Answer 8

B vitamins, folate, biotin, pantothenic acid, vitamin C

Question 9

describe the function of vitamin A

Answer 9

Vision; maintenance of cornea, epithelial cells, mucous membranes, skin; bone and tooth growth; regulation of gene expression; reproduction; immunity

Can be found in
- protein sources such as liver, fish, and dairy
- plant source such as carrots and spinach

Question 10

describe the function of vitamin D

Answer 10

Mineralization of bones and teeth (raises blood calcium and phosphorus by increasing absorption from digestive tract, withdrawing calcium from bones, stimulating retention by kidneys)

Question 11

describe the function of vitamin C

Answer 11

Collagen synthesis (strengthens blood vessel walls, forms scar tissue, provides matrix for bone growth), antioxidant, restores vitamin E to active form, supports immune system, boosts iron absorption

Question 12

describe the function of vitamin B12

Answer 12

Essential for nerve function, DNA synthesis, and red blood cell production.

Question 13

describe the function of folate

Answer 13

Part of a coenzyme needed for new cell synthesis

Question 14

identify the food group(s) that typically contain vitamin A and list three food sources

Answer 14

Vitamin A is commonly found in the vegetable and animal food groups.

Three food sources of vitamin A:

Carrots
spinach
Liver

Question 15

identify the food group(s) that typically contain vitamin D and list three food sources

Answer 15

Vitamin D is primarily found in the dairy and fortified foods group, as well as in some fatty fish.

Three food sources of vitamin D:

Salmon
Milk
Eggs

Question 16

identify the food group(s) that typically contain vitamin C and list three food sources

Answer 16

Vitamin C is commonly found in the fruit and vegetable food groups.

Three food sources of vitamin C:

oranges
strawberries
bell peppers

Question 17

identify the food group(s) that typically contain vitamin b12 and list three food sources

Answer 17

Vitamin B12 is primarily found in the animal-based foods group.

Three food sources of vitamin B12:

beef liver
salmon
eggs

Question 18

identify the food group(s) that typically contain vitamin folate and list three food sources

Answer 18

Vitamin folate is commonly found in the vegetable and legume food groups.

Three food sources of vitamin folate:

spinach
beans
avocado

Question 19

list Canadian population groups vulnerable to deficiencies of vitamin A

Answer 19

The addition of vitamin A to milk and margarine means that vitamin A deficiency is quite rare in Canada.

Infants, children and people who are pregnant or breastfeeding are vulnerable to vitamin A deficiency

Question 20

list Canadian population groups vulnerable to deficiencies of vitamin D

Answer 20

vulnerable populations include children of low income, inner-city families, breastfed infants who do not receive supplemental vitamin D, dark-skinned people who cover up their skin (e.g., some South Asian women), vegetarians who do not drink vitamin D fortified milk, and elderly people living in institutions.

Question 21

list Canadian population groups vulnerable to deficiencies of vitamin C

Answer 21

Low-Income Individuals: Limited access to fresh fruits and vegetables can contribute to inadequate vitamin C intake.

Smokers: Smoking increases the body’s demand for vitamin C, making smokers more susceptible to deficiency.

Elderly Individuals: Reduced dietary intake and impaired absorption can lead to lower vitamin C levels in older adults.

Question 22

list Canadian population groups vulnerable to deficiencies of vitamin b12

Answer 22

Primary deficiency of vitamin B12 is mainly confined to strict vegans (persons living exclusively on foods of plant origin) since this vitamin is present only in foods derived from animals.

Question 23

list Canadian population groups vulnerable to deficiencies of folate

Answer 23

Pregnant Women: Increased folate needs for fetal development can lead to deficiency if dietary intake is inadequate.

Women of Childbearing Age: Adequate folate intake is crucial to prevent neural tube defects during early pregnancy.

People with Alcohol Use Disorder: Alcohol can interfere with folate absorption and metabolism, putting these individuals at risk.

Question 24

discuss vegetable storage and preparation methods that maximize retention of water-soluble vitamins and minerals.

Answer 24

Storage:

• Store vegetables in a cool, dark place or the refrigerator to slow nutrient degradation.
• Avoid prolonged exposure to air and light, which can lead to vitamin loss.

Preparation:

• Choose cooking methods like steaming, microwaving, or stir-frying that minimize water contact.
• Cut vegetables just before cooking to preserve nutrients.
• Use minimal water during cooking and save nutrient-rich cooking water for soups or sauces.

Question 25

discuss the consequences of refining and enriching grains on vitamin and mineral content.

Answer 25

Refining Grains:

Removal of bran and germ during refining reduces fiber, vitamins (B vitamins and vitamin E), and minerals (iron, zinc, magnesium) content.

Enriching Grains:

Addition of some B vitamins (like folic acid) and iron post-refining helps compensate for losses, but enrichment might not restore all lost nutrients.