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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
© 2012 Pearson Education, Inc.
Vitamins and Metabolism
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
© 2012 Pearson Education, Inc.
Vitamins and Metabolism
© 2012 Pearson Education, Inc.
Vitamins and Metabolism
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
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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
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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
© 2012 Pearson Education, Inc.
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
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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
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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
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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 µg/day of folate
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Spina Bifida
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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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
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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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Components of Blood
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Iron
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Iron
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
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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
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Dietary Supplement Regulation
Categorized generally as foods, not drugs
Regulation is less rigorous than for drugs
FDA regulation of supplements marketing iscurrently in flux
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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
© 2012 Pearson Education, Inc.
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?
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
ABC News Nutrition Video
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