Copyright © 2012 Pearson Education, Inc. 10 C H A P T E R Nutrients Involved in Energy Metabolism and Blood Health and In Depth.

Copyright © 2012 Pearson Education, Inc.

10C H A P T E R

Nutrients Involved in Nutrients Involved in Energy Metabolism Energy Metabolism

and Blood Healthand Blood Healthand In Depthand In Depth

© 2012 Pearson Education, Inc.

Vitamins and Metabolism

Vitamins and minerals Are required for proper metabolism Do not directly provide 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

PLAYPLAY Energy Metabolism






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


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 oxidation–reduction 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 4 Ds: dermatitis, diarrhea, dementia, and death


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 in heme 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


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 woman’s need for folate dramatically increases during pregnancy

Folate is required for cell division and proper formation of the neural tube

The neural tube develops into the brain and spinal cord


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 µg/day of folate


Spina Bifida


Folate Deficiency: Anemia

Anemia means “without blood”; any condition of low hemoglobin levels

There are many types and causes of anemia

Anemia “without blood” can be caused by a severe folate deficiency


B-Vitamins: Vitamin B12 (Cobalamin)

Part of coenzymes for blood formation Found only in animal-based foods Deficiency can lead to pernicious anemia Vegans are at risk for deficiency 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 Deficiency is very rare

Biotin: Part of coenzymes involved in the metabolism of

carbohydrates, fat, and proteins Deficiency is very rare


Iodine

Iodine is a trace mineral Critical for the synthesis of thyroid hormones Thyroid hormones regulate body temperature,

growth, and resting metabolic rate Hypo, hyperthyroidism: Hashimoto’s, Grave’s

disease 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


Chromium and Manganese

Chromium is a trace mineral Assists insulin as it transports glucose from the

blood into the cells Good sources: mushrooms, prunes, dark chocolate,

nuts, whole grains

Manganese is a trace mineral Coenzyme involved in energy metabolism Good sources: whole-grain foods, brown rice,

pineapple, pine nuts, okra, spinach


Blood: Iron, Vit. K, Zinc & Copper

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

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


Vitamin K

Vitamin K is 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 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


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 factor and vitamin C enhance absorption


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 What if you don’t 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


Zinc and Copper: trace minerals

Functions of zinc: Cofactor for hemoglobin production Assists in energy metabolism, immune system and

growth

Sources of zinc Red meats, some seafood, whole grains, enriched

grains and cereals

Functions of copper Cofactor for energy metabolism Coenzyme that assists in collagen production

Sources of copper Organ meats, seafood, nuts, seeds, whole-grain foods


In Depth: Dietary Supplements

Dietary supplements are defined by the FDA as products taken by mouth containing a dietary ingredient 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 drugs

Regulation is less rigorous than for drugs

FDA regulation of supplements marketing iscurrently in flux


What Consumers Should Know

FDA approval is not needed for marketingManufacturers are solely responsible for safetySellers are not required to show evidence of

safetyThere are no federal guidelines to ensure purity,

safety, or compositionNo rules limit serving sizesOnce a supplement is marketed, the FDA must

prove it is unsafe for it to be removed fromstores


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


Should You Take Supplements?

Many people do not need supplementsSupplements are not substitutes for whole foodsSome individuals who may benefit from

supplements include:VegansAthletes Infants and childrenPregnant teens and pregnant womenElderly peopleConvalescents


ABC News Nutrition Video

Too Much of a Good Thing? New Vitamins and Cancer Study

Copyright © 2012 Pearson Education, Inc. 10 C H A P T E R Nutrients Involved in Energy Metabolism and Blood Health and In Depth.

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