Chapter Images shutterstock.com The Micronutrients: Vitamins and Minerals 13.

Chapter

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The Micronutrients:Vitamins and Minerals

13

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Objectives

• Differentiate between fat-soluble vitamins and water-soluble vitamins.

• List functions and sources of major minerals and trace minerals.

• Explain the impact food processing and preservation methods have on the nutritive value of food.

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Objectives

• Identify non-nutritive functions of vitamins and minerals used as food additives.

• Describe how to reduce vitamin and mineral losses during home food storage and preparation.


Vitamins

• Vitamins are organic compounds needed in small amounts in the diet to help regulate body processes– Enzyme reactions are slowed or stopped

and body processes impaired if vitamins are missing

• Scientists gave vitamins names, letters, or numbers to identify them

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Vitamins

• Fat-soluble vitamins– have a nonpolar molecular structure and

dissolve in fats and oils– include vitamins A, D, E and K

• Water-soluble vitamins– are polar and dissolve in water and

water-based liquids– include the B vitamins and vitamin C


Fat-Soluble Vitamins

• Bile from the liver is needed for digestion

• A surplus is stored in the liver and in fatty tissue for future use

• They cannot be easily excreted once absorbed

• Megadoses can build up to poisonous levels


Vitamin A

• Fat-soluble vitamin A– aids in night vision– maintains healthy skin and internal lining

of lungs and digestive tract– ensures proper immune system function– ensures production and regulation of

hormones– breaks down bone for reshaping during

growth

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Vitamin A

• Vitamin A is found in 2 basic forms in food– Retinol is the active form of vitamin A

and is found in liver, eggs, butter, milk, and cheese

– A precursor for retinol, found in orange and dark green fruits and vegetables, is called beta-carotene (β-carotene)


Vitamin D

• Fat-soluble vitamin D– can be made by the body with the help of

the vitamin D precursors cholecalciferol and ergocalciferol

– teams with other nutrients to regulate calcium levels and form bones and teeth

– is available in butter, cream, egg yolks, and fatty fish and by exposing the skin to sunlight


Vitamin E

• Fat-soluble vitamin E is– an important antioxidant that quickly

reacts with oxygen, preventing damage to body tissues

– found in vegetable oils, whole grains, avocados, nuts, and seeds

– not heat stable so foods that are fried have little vitamin E remaining


Vitamin K

• Fat-soluble vitamin K is– necessary for production of proteins

involved in blood clotting– produced by bacteria in the intestines– found in liver and dark leafy greens

©Elena Elisseeva/Shutterstock.com


Water-Soluble Vitamins

• These vitamins cannot be stored in the body since they dissolve in water– Excess quantities are

excreted in urine, making it impossible to receive toxic doses of water-soluble vitamins

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B-Complex Vitamins

• Water-soluble B-complex vitamins – act as coenzymes in reactions

throughout the body– are found in leafy greens, legumes, pork,

whole grains, eggs, fish, and milk

• The B-complex vitamins specialize– Vitamin B1 helps nerve and muscle

function– Vitamin B2 promotes healthy skin and

eyesight continued


B-Complex Vitamins

• The B-complex vitamins specialize– Vitamin B3 keeps the skin and nervous

system healthy and promotes normal digestion

– Pantothenic acid promotes growth and helps synthesize vital substances

– Biotin helps the body make fats and glycogen

– Vitamin B6 promotes healthy immune systems and helps make hemoglobin

– Folate helps cells divide to form new cells


Vitamin C

• Water-soluble vitamin C– is called ascorbic acid– helps produce connective tissue– helps protect against infections– helps the body absorb iron and calcium– serves as an antioxidant– is found in citrus fruits, cantaloupe,

tomatoes, strawberries, broccoli


Nonvitamins

• Several substances not classified as vitamins are recognized as needed to maintain good health

• Choline is– found in meats, eggs, and peanuts

• Coenzyme Q10 is– involved in enzyme reactions– found in meat, fish, poultry, and nuts


Minerals

• Minerals have the simplest structure of all nutrients because they are elements

• They are grouped into 2 categories– Major minerals are needed in amounts

of 100 mg or more per day– Trace minerals are needed in amounts

of less than 100 mg per day


Major Minerals

• Calcium– is part of bones and teeth– regulates movement of ions across cell

membranes– is important in sending messages along

nerve fibers and for muscle contraction– helps maintain blood pressure– is found in milk, yogurt, cottage cheese,

broccoli, collards, kale, and mustard greens

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Major Minerals

• Phosphorus– is found in bone tissue– works as a salt buffer in the body’s acid-

base balance– is part of the cell’s genetic material– forms part of cell membranes and

regulates enzymes– is found in meats and soft drinks

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Major Minerals

• Sodium– helps maintain fluid balance in cells– helps regulate body temperature through

sweating– is found in processed foods, salt, soy

sauce– should be consumed in limited amounts

by people who are salt-sensitive due to a link between high blood pressure and a high sodium intake

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Major Minerals

• Potassium– helps maintain fluid balance– helps regulate body temperature– plays a critical role in maintaining the

heartbeat– is found in meats, milk, fruits,

vegetables, and grains

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Major Minerals

• Chloride– helps maintain the body’s fluid balance– is used in the stomach’s hydrocholoric

acid– can be found in salt and soy sauce

• Sulfur – is found in protein-rich foods– helps maintain normal acid-base balance – helps the liver change toxins to harmless

substances continued


Major Minerals

• Magnesium– assists hundreds of enzymatic reactions– is essential for bone health– is needed for energy to be released for

muscle contractions– helps nerves send messages– is found in legumes, whole grains, and

dark green vegetables


Trace Minerals

• Iron– is needed for the production of red blood

cells– moves oxygen from blood throughout the

body– is inhibited by tea, coffee, soy protein,

wheat bran, and fiber from being absorbed

– is aided by Vitamin C in being absorbed– is found in milk, legumes, dark leafy

greens, dried fruit, whole grains, breads, and cereals

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Trace Minerals

• Iodine is– needed for the production of thyroxine, a

hormone regulating the body’s use of energy

– found in iodized salt and seafood

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Trace Minerals

• Zinc– is needed for the functioning of enzymes– promotes wound healing and proper

immune function– is found in meat, fish, poultry, legumes,

whole grains, and nuts

• Fluoride– helps strengthen bones and teeth and is

found in drinking water


Other Trace Minerals

• Copper– aids in the production of red blood cells

and the use of iron

• Manganese– is involved in metabolism of

macronutrients

• Chromium– is necessary for proper insulin action

• Selenium– works with vitamin E to protect body

tissuecontinued


Other Trace Minerals

• Molybdenum– is part of several enzymes– is found in legumes, grains, and nuts

• Other trace minerals found in even smaller quantities in the body are– arsenic, boron, nickel, silicon, and

vanadium


Effects of Processing and Preservation• Removing components of natural food

changes nutritive value• Exposure to heat, oxygen, or moisture

during processing affects a food’s nutrient content

• Interactions between components can reduce or limit the ability to absorb some nutrients

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Effects of Processing and Preservation• Enrichment is the process of

restoring some nutrients removed from refined grain products during processing

• Laws were passed to prevent deficiencies– 1930s—Niacin, thiamin, riboflavin, and

iron were first added to processed flour– 1996—Folic acid was first added to grain

and cereal products continued


Effects of Processing and Preservation• Fortification is adding nutrients to

food to correct a nutritional deficiency– A fortificant is the nutrient that is being

added to the food– The food vehicle is the specific food to

which a fortificant is added– Examples include iodine in salt, vitamin

D in milk, calcium in orange juice, vitamin A in rice

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Effects of Processing and Preservation• Food scientists examine the

bioavailability of the proposed fortificant– The most highly soluble form may be

added because of the body’s ability to absorb it

– A fortificant may not be added to a food that contains nutrients that hinder the body’s ability to absorb it


Factors Affecting Nutrient Stability• Heat

– Vitamins A, B1, C, and E are not heat stable

• Oxygen– Vitamins C, E, and β-carotene are

damaged by oxygen

• Water activity level (AW)– affects the stability of vitamins A and C


Vitamins and Minerals as Food Additives• Non-nutritive functions of vitamins

and minerals include– vitamin C as an enzyme inhibitor– calcium as a stabilizer in tofu and canned

vegetables– salt (sodium and chloride) as

preservative and flavor enhancer in processed foods

– iodine as a dough conditioner


Preserving Vitamins and Minerals at Home• How food is prepared determines how

much damage is done to its nutritional value

• To reduce nutrient losses– rinse fresh foods rather than soaking

them– keep foods in large pieces to reduce the

size of surface area exposed to light, air, and water

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Preserving Vitamins and Minerals at Home– To reduce nutrient losses

– cut up fruits and vegetables just before cooking or serving

– choose stainless steel, glass, and aluminum cookware for foods that are easily oxidized

– avoid adding acids or alkalis to vegetables

– choose steaming over boiling and use the cooking water in soups, gravies, or sauces


• Vitamins are organic compounds that help regulate body processes– Fat-soluble vitamins dissolve in fats

and oils– Water-soluble vitamins dissolve in

water and water-based liquids

• Minerals can be categorized as– major minerals– trace minerals

Recap

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• Both vitamins and minerals serve various functions in body processes

• Nutrients can be added to foods by– enrichment or fortification

• Factors that affect nutrient stability are– heat– oxygen– water activity level

Recap

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• When care is taken to preserve a food’s vitamin content, its mineral content and other nutrients are likely to be preserved

Recap

Chapter Images shutterstock.com The Micronutrients: Vitamins and Minerals 13.

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