Ch 10 PPT Lecture (Nutr 121)

8/13/2019 Ch 10 PPT Lecture (Nutr 121)

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Copyright 2012 Pearson Education, Inc.

10C H A P T E R

Nutrients Involved inEnergy Metabolism

and Blood Health

and In Depth

2012 Pearson Education, Inc.

Vitamins and Metabolism

Vitamins and minerals

Are required for proper metabolism

Do not directlyprovide energy

Are necessary for obtaining energy from

macronutrients

Often function as coenzymes



Enzyme: a protein that accelerates the rate of a

chemical reaction

Enzymes are required for all metabolic reactions

Coenzyme: a molecule that combines with an

enzyme to activate it

Some metabolic reactions require coenzymes


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B-Vitamins

The B-vitamins are especially important for energy

metabolism

The B-vitamins include:thiamin (B1) folate

riboflavin (B2) vitamin B12

niacin pantothenic acid

vitamin B6 biotin


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B-Vitamins: Thiamin (Vitamin B1)

Coenzyme thiamin pyrophosphate is required for

carbohydrate metabolism

Coenzyme for the metabolism of some fatty acids Enriched foods, whole grains, and pork are good

sources

Beriberi: deficiency of thiamin resulting in muscle

wasting and nerve damage, and heart failure


B-Vitamins: Riboflavin (Vitamin B2)

Part of coenzymes involved in oxidationreduction

reactions

Part of the antioxidant enzyme glutathione

peroxidase

Milk is a good source of riboflavin

Ariboflavinosis: riboflavin deficiency that causes

sore throat and swollen mucous membranes


B-Vitamins: Niacin

Nicotinamide and nicotinic acid

Coenzyme assists with the metabolism of

carbohydrates and fatty acids

Good sources: meat, fish, poultry, enriched bread

products

Toxicity can result from supplements

Pellagra: severe niacin deficiency

First seen in populations where dietary staple was corn

4 Ds: dermatitis, diarrhea, dementia, and death


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B-Vitamins: Vitamin B6 (Pyridoxine)

Group of six related compounds

Part of a coenzyme for more than 100 enzymes, assists in

amino acid metabolism, neurotransmitter, and assists inheme synthesis

Good sources: enriched cereals, meat, fish, poultry,

starchy vegetables

Toxicity from supplements can result in nerve damage

and skin lesions

Deficiency: anemia, elevated levels of homocysteine

High homocysteine in blood is associated with heart disease


B-Vitamins: Folate

Involved in DNA synthesis, amino acid

metabolism, red blood cell synthesis

Critical for cell division of very early embryos

Good sources: ready-to-eat cereals, enriched bread

products

Toxicity can mask vitamin B12 deficiency

Deficiency: macrocytic anemia


Folate Deficiency: Neural Tube Defects

A womans need for folate dramatically increases

during pregnancy

Folate is required for cell division and properformation of the neural tube

The neural tube develops into the brain and spinal

cord


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Folate Deficiency: Neural Tube Defects

The increased need for folate is critical very early

(first 4 weeks) in pregnancy, frequently before a

woman knows she is pregnant

All women capable of becoming pregnant should

consume an extra 400 g/day of folate


Vascular Disease

Folate and vitamin B12 are required for the

breakdown of the amino acid homocysteine

Low folate, vitamin B12, and vitamin B6 intake may

cause an increased level of homocysteine

High homocysteine levels are associated with greater

risk of cardiovascular and cerebrovascular disease


Folate Deficiency: Anemia

Anemia means without blood; any condition of

low hemoglobin levels

There are many types and causes of anemia


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Folate Deficiency: Macrocytic Anemia

Caused by a severe folate deficiency

Results in enlarged red blood cells carrying

insufficient hemoglobin Shows common symptoms of anemia, including

weakness, fatigue, difficulty concentrating,

irritability, headache, and shortness of breath


B-Vitamins: Vitamin B12 (Cobalamin)

Part of coenzymes for blood formation

Required for nerve functioning

Required for homocysteine breakdown

Found only in animal-based foods

Deficiency results in anemia, low energy, fatigue,

shortness of breath, and can lead topernicious

anemia


B-Vitamins: Vitamin B12 (Cobalamin)

Deficiency is due to insufficient intake or inability

to absorb the vitamin

Absorption requires: intrinsic factor and low

stomach pH

Lack of intrinsic factor production can occur

Atrophic gastritis results in inadequate stomach

acid production

Vegans are at risk for deficiency


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Vitamin B12 (Cobalamin): Pernicious Anemia

Pernicious means causing great harm or fatal

Caused by vitamin B12 deficiency

Due to low acid production in the stomach or lackof gastric intrinsic factor production

Also occurs in people who consume very little

vitamin B12 in their diet

Symptoms are pale skin, reduced energy, fatigue,

and neurological symptoms


B-Vitamins: Pantothenic Acid

Component of coenzymes for fatty acid metabolism

Required for building new fatty acids

Good sources: chicken, beef, egg yolk, potatoes,

oat cereals, tomato products

No toxicity from excess pantothenic acid

Deficiency is very rare


B-Vitamins: Biotin

Part of coenzymes involved in the metabolism of

carbohydrates, fats, and proteins

Important for gluconeogenesis

Biotin content has been determined for very few

foods

Deficiency symptoms include hair thinning, loss of

hair color, and red rash on face

Deficiency is very rare

Can be caused by over consumption of raw egg whites


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Choline

Choline is a vitamin-like substance

Assists in homocysteine metabolism

Accelerates the synthesis of acetylcholine,

a neurotransmitter

Good sources: milk, liver, eggs, peanuts

Deficiency can lead to fat accumulation in the liver

Toxicity can result from supplements


Iodine

Iodine is a trace mineral

Critical for the synthesis of thyroid hormones

Thyroid hormones regulate body temperature,

growth, and resting metabolic rate

Good sources: saltwater fish, shrimp, iodized salt,

milk and dairy products


Iodine

Excess iodine

Blocks synthesis of thyroid hormones

Thyroid tries to make more hormones

Results in goiter: enlarged thyroid

Iodine deficiency

Results in hypothyroidism and goiter

Cretinism: mental retardation from iodine

deficiency during embryonic development


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Chromium

Chromium is a trace mineral

Assists insulin as it transports glucose from the

blood into the cells

Plays a role in immune function and growth

There is very little chromium in the body

Good sources: mushrooms, prunes, dark chocolate,

nuts, whole grains

Chromium deficiency inhibits glucose absorption

by body cells


Manganese

Manganese is a trace mineral

Coenzyme involved in energy metabolism

Part of the antioxidant enzyme superoxide

dismutase

Good sources: whole-grain foods, brown rice,

pineapple, pine nuts, okra, spinach

Toxicity impairs the nervous system, causing

spasms and tremors


Sulfur

Sulfuris a major mineral

Component of thiamin and biotin

Stabilizes protein structure

Required for detoxification of alcohol and drugs bythe liver

Found in two amino acids

Requirement for sulfur is met by the protein in our

diets


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Blood

Blood is the only fluid tissue in the body

Functions

Transport of oxygen and nutrients to cells

Removal of waste products from cells


Components of Blood

Erythrocytes: red blood cells

Transport oxygen through the body

Leukocytes: white blood cells of the immune

system

Platelets: cell fragments that assist in blood clotting

Plasma: the fluid portion of the blood


Components of Blood


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Vitamin K

Vitamin Kis a fat-soluble vitamin

Coenzyme for the synthesis of proteins involved in

blood clotting

Healthful intestinal bacteria produce some

vitamin K

Good sources: green leafy vegetables

Deficiencies can result from diseases that disturb

absorption of fats (Crohns disease)

Newborns are given vitamin K at birth


Iron

Iron is a trace mineral

Functions of iron

A component of the protein hemoglobin, which

carries oxygen in erythrocytes

A component of myoglobin, which carries oxygen

in muscle cells

A coenzyme involved in the metabolism of

carbohydrates, fats, and proteins


Iron


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Iron

Iron can be stored in the body as ferritin or

homosiderin

Storage is usually in the liver, bone marrow,intestinal mucosa, and spleen

Two types of iron are found in foods

Heme ironfound in animal-based foods and is

more absorbable

Non-heme ironnot easily absorbed; iron not part

of hemoglobin or myoglobin


Iron

Recommended intake

Recommended Dietary Allowance (RDA) varies

based on age and gender

8 mg/day for adult men

27 mg/day for pregnant women

Sources of iron

Meat, poultry, fish, clams, oysters, enriched cereals

and breads

Meat factorand vitamin C enhance absorption Dairy decreases absorption of iron


Iron

What if you consume too much iron?

Iron overdose is the most common cause of

poisoning deaths in children

Toxicity symptoms: nausea, vomiting, diarrhea,

dizziness, confusion

Delayed treatment of iron toxicity can result in

severe damage to the heart, central nervous system,

liver, and kidneys

Hemochromatosisexcessive iron absorption


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Iron

What if you dont consume enough iron?

Iron deficiency is the most common nutrient

deficiency in the world

High-risk people include infants, young children,

preadolescent girls, premenopausal women, and

pregnant women

There are three stages of iron deficiency


Iron


Iron-Deficient Anemia

Iron deficiency results in small red blood cells that

do not carry enough hemoglobin

Symptoms are fatigue, pale skin, impaired work

performance, depressed immune function, and

impaired memory


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Zinc

Zinc is a trace mineral

Functions of zinc

Cofactor for hemoglobin production

Part of superoxide dismutase antioxidant enzyme

system

Development and function of immune system

Growth

Assists in energy metabolism


Zinc

Recommended intake

RDA is 8 mg/day for women

11 mg/day for men

Sources of zinc

Red meats, some seafood, whole grains, enriched

grains and cereals


Zinc

What if you consume too much zinc?

Toxicity can occur from supplements

Symptoms are intestinal pain, cramps, nausea,

vomiting, and loss of appetite

What if you dont consume enough zinc?

Deficiencies are uncommon in the United States

Symptoms are growth retardation, diarrhea, and

delayed sexual maturation


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Copper

Copperis a trace mineral

Functions of copper

Cofactor for energy metabolism

Coenzyme that assists in collagen production

Part of superoxide dismutase antioxidant enzyme

system

Required for iron transport


Copper

Recommended intake

RDA for adults is 900 g/day

Sources of copper

Organ meats, seafood, nuts, seeds, whole-grain

foods


Copper

What if you consume too much copper?

Toxicity is not well studied in humans

Symptoms are intestinal pain, cramps, nausea,

vomiting, and liver damage

What if you dont consume enough copper?

Copper deficiency is rare

Symptoms are anemia, reduced number of white

blood cells, and osteoporosis in children


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In Depth: Dietary Supplements

Dietary supplements are defined by the FDA as

products taken by mouth containing a dietaryingredient intended to supplement the diet


In Depth: Dietary Supplements

May contain:

Vitamins

Minerals

Herbs or other botanicals

Amino acids

Enzymes

Tissues from animal organs or glands

or a concentrate, a metabolite, a constituent,

or an extract


Dietary Supplement Regulation

Categorized generally as foods, not food

additives or drugs

Regulation is less rigorous than for foodadditives or drugs

FDA regulation of supplements marketing is

currently in flux


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What Consumers Should Know

FDA approval is not needed for marketing

Manufacturers are solely responsible for safety

Sellers are not required to show evidence of

safety

Purity, safety, or composition may be

questionable

No rules limit serving sizes

Once a supplement is marketed, the FDA must

prove it is unsafe for it to be removed from

stores


Avoiding Web-Based Supplements Fraud

Critically assess the Web site:

What is its purpose?

Is information accurate?

Does it use reputable references?

Who owns or sponsors the site?

Who wrote the information?

Is the information current?


Herbal Supplements

An herb (or botanical) is a plant or plant part

used for its scent, flavor, and/or therapeutic

properties

Consult your healthcare provider before using

herbal supplements Herbs may cause serious medical problems if

used in large amounts

Avoid using herbs when pregnant or nursing,

unless you have consulted a doctor

Active ingredients in many herbs and herbal

supplements are not known


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Should You Take Supplements?

Many people do not need supplements

Supplements are not substitutes for whole foods

Some individuals who may benefit from

supplements include:

Vegans

Athletes

Infants and children

Pregnant teens and pregnant women

Elderly people

Convalescents


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Ch 10 PPT Lecture (Nutr 121)

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