Chapter 8 - Nutrients Essential to Key Body Functions

What do vitamins and minerals do in energy metabolism

They help generate energy from macronutrients but do not provide Calories themselves

What are coenzymes

Organic molecules that bind to the active site of an enzyme to activate it

Why are coenzymes essential

Without coenzymes energy cannot be produced to sustain life

What is thiamin also called

Vitamin B1

What is the role of thiamin pyrophosphate TPP

It is a coenzyme critical for carbohydrate metabolism and branched-chain amino acid metabolism.

What else does TPP help produce

DNA RNA and neurotransmitters

What are food sources of thiamin

Whole grains pork green vegetables and okra

What is the deficiency disease associated with thiamin

Beriberi

What are the symptoms of thiamin deficiency

Muscle wasting, nerve damage, muscle weakness, fatigue, and reduced cognitive function

Who is at risk of thiamin deficiency

People with poor quality food supplies and people with heavy alcohol consumption and limited food intake

What is the tolerable upper intake level for thiamin

None has been established

What are the coenzyme forms of riboflavin

Flavin mononucleotide FMN and flavin adenine dinucleotide FAD

What does riboflavin do in energy metabolism

It helps metabolize carbohydrates and fats

How is riboflavin involved in antioxidant defense

It is part of the antioxidant enzyme glutathione peroxidase

What is the deficiency disease associated with riboflavin

Ariboflavinosis

What are food sources of riboflavin

Milk fish eggs poultry products green vegetables and fortified foods

What is known about riboflavin toxicity

No known toxicity

What does niacin do

It helps metabolize carbohydrates and fatty acids and assists in DNA replication and cell differentiation

Which amino acid can be converted into niacin

Tryptophan

What is the deficiency disease associated with niacin

Pellagra

What does pellagra mean

Angry skin

What are the four major symptoms of pellagra

Dermatitis, diarrhea, dementia, and death

Who is at risk of niacin deficiency

People in impoverished areas and people with chronic alcoholism

What are food sources of niacin

Meats fish and whole grains

What can happen when niacin supplements are taken in excess

Flushing with burning, tingling, or itching sensations and redness of the face, arms, or chest

What is another name for vitamin B6

Pyridoxine

What are the major functions of vitamin B6

Amino acid metabolism through transamination, neurotransmitter synthesis, carbohydrate metabolism, heme synthesis, immune function, and metabolism of niacin and folate

What is homocysteine

An amino acid that requires adequate folate, vitamin B6, and vitamin B12 for metabolism

What is associated with high blood homocysteine levels

An increased risk of cardiovascular disease

What is the main role of folate in the body

It adds one-carbon units to other organic compounds

What processes require folate

Nucleotide synthesis for DNA and cell division amino acid metabolism and red blood cell synthesis

Why is folate especially important during pregnancy

It plays a critical role in spinal cord formation

What are food sources of folate

Leafy greens fortified grain products and ready-to-eat cereals

What does vitamin B12 do

It is involved in fatty acid metabolism maintains the myelin sheath of nerves and helps prevent homocysteine buildup

What are food sources of vitamin B12

Meats dairy eggs fortified soy milk and cereals

Who is at risk of vitamin B12 deficiency

Vegans and individuals with atrophic gastritis or autoimmune diseases

What is intrinsic factor

It is required for vitamin B12 absorption

What condition can result from problems involving intrinsic factor

Pernicious anemia

What is known about vitamin B12 toxicity

No known toxicity

How is vitamin B12 related to folate

It converts folate to its active form

What does pantothenic acid do

It is a component of all energy-producing pathways and is especially important for fatty acid breakdown and synthesis

What are food sources of pantothenic acid

Meats eggs potatoes oats tomatoes whole grains and yeast

Which vitamins and minerals are identified as antioxidants

Vitamins E C and A plus selenium copper iron and manganese

What carotenoid is identified as having antioxidant properties

Beta-carotene

What damage can free radicals cause

They damage cell membranes and proteins and can damage DNA causing harmful mutations

Which diseases are linked to free radicals

Cancer type 2 diabetes Alzheimer disease Parkinson disease and cardiovascular disease

What is vitamin E

It is a fat-soluble vitamin with tocotrienol as a biologically inactive form and tocopherol as a biologically active form

What is the primary function of vitamin E

It acts as an antioxidant

What does vitamin E protect

Polyunsaturated fatty acids and low-density lipoproteins

What is the RDA for vitamin E

15 mg of alpha-tocopherol per day

What is the tolerable upper limit for vitamin E

1000 mg per day

What are food sources of vitamin E

Vegetable oils nuts seeds wheat germ and soybeans

Are animal and dairy products good sources of vitamin E

No they are poor sources

What are possible risks of excessive vitamin E intake

Some studies suggest links to vascular disease, diabetes, heart failure, and prostate cancer

What side effects can excessive vitamin E cause

Nausea intestinal distress and diarrhea

What medication interaction is associated with vitamin E

It can interfere with anticoagulant medications

What can vitamin E deficiency cause

Fragile red blood cells, loss of muscle coordination and reflexes, and impaired immune function

What type of vitamin is vitamin C

It is a water-soluble vitamin that must be consumed in the diet

What are the functions of vitamin C

Antioxidant activity, collagen synthesis, scurvy prevention, immune support, vitamin E regeneration, and enhanced iron absorption

Does vitamin C prevent colds

It has not been shown to ward off colds but may reduce the duration of symptoms

What is the recommended daily vitamin C intake for men

90 mg per day

What is the recommended daily vitamin C intake for women

75 mg per day

How much additional vitamin C do smokers need

35 mg per day

What is the adult tolerable upper limit for vitamin C

2000 mg per day

What are food sources of vitamin C

Fresh fruits and vegetables

How does heat affect vitamin C

Heat destroys vitamin C and cooking lowers food vitamin C content

What can megadoses of vitamin C cause

Nausea, diarrhea, nosebleeds, and abdominal cramps

What risks can excess vitamin C create for people with certain conditions

Iron toxicity in people with hemochromatosis and kidney stone formation in people with kidney disease

What is the most common vitamin C deficiency disease

Scurvy

What are symptoms of scurvy

Bleeding gums loose teeth wounds that fail to heal swollen ankles and wrists bone pain fractures diarrhea weakness and depression

What other condition can vitamin C deficiency cause

Anemia

What type of mineral is selenium

It is a trace mineral found in a few amino acids in the body

What are the functions of selenium

It supports antioxidant activity through glutathione peroxidase and the production of the thyroid hormone thyroxine

What is the recommended daily selenium intake

55 micrograms per day for men and women

What is the tolerable upper limit for selenium

400 micrograms per day

What are food sources of selenium

Organ meats pork seafood fish and nuts

What can selenium toxicity cause

Brittle hair, brittle nails, and skin rashes

What diseases are associated with selenium deficiency

Keshan disease which is a form of heart disease and Kashin-Beck disease which is a type of arthritis

What is a cofactor

An organic or inorganic compound needed for proper functioning of an enzyme

Which minerals are cofactors for the superoxide dismutase antioxidant enzyme system

Copper zinc and manganese

Which minerals help maintain blood health

Copper iron and zinc

What role does manganese have in metabolism

It is an important cofactor in carbohydrate metabolism

What is beta-carotene

It is a carotenoid and a provitamin that must be converted into an active vitamin form in the body

What active form of vitamin A is beta-carotene a precursor to

Retinol

What are the antioxidant functions of beta-carotene

It is a relatively weak antioxidant that is effective against oxidation in cell membranes and LDLs

What other benefits are associated with carotenoids

They enhance the immune system and help protect skin from UV light and eyes from damage

Is beta-carotene an essential nutrient

No it is not considered an essential nutrient and no RDA has been established

What are food sources of beta-carotene

Red orange yellow and deep-green fruits and vegetables

How does cooking affect carotenoid absorption

Carotenoids are better absorbed from cooked foods

What can high beta-carotene intake do to the skin

It may turn the skin yellow or orange which is harmless and reversible

Are there known beta-carotene deficiency symptoms

None are known

What type of vitamin is vitamin A

It is a fat-soluble vitamin

Where is excess vitamin A stored

In the liver, adipose tissue, kidneys, and lungs

What are the three active forms of vitamin A

Retinol, retinal, and retinoic acid

What are the major functions of vitamin A

Cell differentiation, reproduction, bone growth, possible antioxidant activity, and vision

How does vitamin A help vision

It enables the eyes to react to changes in light brightness

What is the RDA for vitamin A in men

900 micrograms per day

What is the RDA for vitamin A in women

700 micrograms per day

What are food sources of vitamin A

Animal sources include liver and eggs while plant sources include carotenoid-rich dark-green orange and deep-yellow fruits and vegetables

What are the risks of excessive vitamin A intake

Vitamin A is highly toxic especially from supplements and can cause birth defects and permanent liver and eye damage