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Chapter 3. The Micronutrients of Balanced Meals: Vitamins, Minerals, and Phytochemicals. Introduction. Vitamins, minerals, and phytochemicals , as found in foods, are necessary to help the body function in a variety of ways.

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Chapter 3

Chapter 3

The Micronutrients of Balanced Meals: Vitamins, Minerals, and Phytochemicals


Introduction

Introduction

Vitamins, minerals, and phytochemicals, as found in foods, are necessary to help the body function in a variety of ways.

Supplements have been available since the early 20th century, but much remains to be known about when supplements are helpful and harmful.

A well-balanced diet can provide all needed nutrients, although supplements, used wisely, can serve a vital role.


Plants produce vitamins through their genetic makeup

Plants Produce Vitamins Through Their Genetic Makeup

Vitamins are organic and can be broken down

Vitamins are grouped based on their ability to dissolve in fat or water

Fat-soluble vitamins—A, D, E, K (stored in the body; require dietary fat intake for absorption)

Water-soluble vitamins—Bs, C (not stored in the body; needed on a daily basis)


Medical causes of vitamin deficiency

Medical Causes of Vitamin Deficiency

Fat-soluble vitamins (A, D, E, K)

Fat-malabsorption due to:

Cystic fibrosis

Surgical removal of the ileum (lowest portion of the small intestine)

Medications/fat substitutes (Olestra) that inhibit absorption of fat

Water-soluble vitamins (B vitamins, vitamin C)

Medications such as proton pump inhibitors and anti-epileptic medications

Excess urination due to diuretic treatment or excess fluid intake


Vitamin a and beta carotene

Vitamin A and Beta Carotene

Two types of vitamin A:

Precursor—carotene (deep orange color as found in carrots, sweet potatoes, cantaloupe; also found in dark green, leafy vegetables); the liver uses the precursor form to make vitamin A

Oranges are the exception to the color rule

Because the precursor form allows production of vitamin A, it is simply referred to as vitamin A

Preformed—retinol/retinol palmitate (liver, supplements); also found in water-soluble forms (the most toxic and form typically used in food fortification)

Carotene—harmless but can turn skin to orange color; avoidance of carotene allows return to normal color


Functions of vitamin a

Functions of Vitamin A

Vitamin A is needed for:

Retinal health and night vision

Promoting good immunity

Maintaining skin health (epithelial tissue)

Promoting bone growth

Reproduction

Preventing a form of iron deficiency

(Kelleher and Lonnerdal, 2005)


Vitamin d sunshine vitamin

Vitamin D:“Sunshine Vitamin”

Dietary intake is either from fortified foods (milk) or as naturally found in fish liver (cod liver oil or whole fish [with liver])

Cod liver oil advised by doctors to prevent rickets in children in the early 20th century

Sun allows conversion in the skin of cholesterol into vitamin D

Melanin interferes with sun’s ability to produce vitamin D

Compromise message of sun exposure to prevent skin cancer while meeting vitamin D needs

20 minutes of sun exposure without sunscreen lotion

Latitudes north of Philadelphia: the sun is too weak to make vitamin D in the skin from September through March

Increased intakes of at least 800 IU advised in Northern climates; may be as many as 2000 IU needed


Functions of vitamin d

Functions of Vitamin D

Allows calcium absorption for strong bones and teeth and allows the body’s use of calcium

Needed for a strong and healthy immune system

Helps prevent autoimmune diseases (type 1 diabetes, multiple sclerosis [MS]—Olympic skiers have the highest rate of MS)

May help prevent “winter blues,” or seasonal affective disorder (SAD)

Helps regulate blood pressure and acts as a tumor suppressant to help prevent cancer


Vitamin d deficiency

Vitamin D Deficiency

Can cause bone loss, rickets, and secondary hyperparathyroidism

Breastfed infants are advised to take vitamin D supplements to help prevent rickets

Screening of vitamin D status advised for high-risk groups, including those treated for epilepsy (Nettekoven et al., 2008)

Other associations with deficiency:

Impaired neuromuscular function with muscle pain

Tuberculosis and/or impaired immunity

Rheumatoid arthritis

Multiple sclerosis (MS)

Inflammatory bowel disease

Hypertension

Diabetes


Vitamin e tocopherol

Vitamin E: Tocopherol

Originally discovered as necessary for rat reproduction

Appears necessary for fetal growth

An antioxidant vitamin—helps prevent cellular damage caused by oxidation

Helps regulate cell signaling and gene expression

Sources—nuts and peanut butter, vegetable oils, wheat germ


Chapter 3

FYI

Vitamin E during pregnancy may reduce risk of childhood asthma (Seaton, 2008)

Vitamin E inadequacy during pregnancy may be linked with low birth-weight and smaller head circumference (Masters et al., 2007)

Excess or deficiency of vitamin E appears linked to inflammation (Wagner et al., 2008; Gianello et al., 2007)


Vitamin k phylloquinone

Vitamin K: Phylloquinone

Allows for clotting of blood

Involved in vascular function and bone metabolism

Evidence it supports bone growth

Found in green leafy vegetables, green tea, cauliflower, butter, soybean oil, legumes

Intestinal bacteria produce vitamin K

Only concern is usually related to Coumadin (an anticlotting medication), which necessitates stable intake of vitamin K; antibiotics used to treat gram-negative bacteria can cause vitamin K deficiency, with potential for increased effect of Coumadin


Deficiency concerns of vitamin k

Deficiency Concerns of Vitamin K

Newborn infants generally require injection at birth because of lack of intestinal bacteria

Intracranial hemorrhage (ICH) at 1 to 2 months of age; signs and symptoms: vomiting, absence of pupil reaction, fontanel bulging, convulsions, irritability with coma

Vitamin K supplement needed for infants with antibiotic treatment, diarrhea, liver problems, or breastfeeding

With long-term use of antibiotics for gram-negative bacteria for children and adults, supplementation is advised


Water soluble vitamins

Water-Soluble Vitamins

Water-soluble vitamins

B vitamins

B1: thiaminB8: biotin*

B2: riboflavinB9: folate*

B3: niacinB12: cobalamin

B5: pantothenic acid* choline

B6: pyridoxine and related substances

*not generally referred to numerically

Vitamin C (ascorbic acid)


B vitamins

B Vitamins

Easily destroyed with cooking

Serve as cofactors to allow cellular metabolism; needed for energy production in the mitochondria

Most B vitamins found in whole grains and legumes

B2 found mainly in milk, eggs, peanuts, organ meats

B3 requirement met, in part, by production from the amino acid tryptophan

B12 found in animal products only


Hyperhomocysteinemia

Hyperhomocysteinemia

A condition related to deficiency of B vitamins

Linked with neurodegenerative diseases and dementia (Hermann et al., 2007)

An increased intake of the B vitamins (especially folate, B6, and B12) may improve brain function

Other conditions that may benefit with increased intake of B vitamins include

Parkinson’s disease with L-dopa medication

Multiple sclerosis

Epilepsy and Acid-Reflux due to medications


Folate names for foliage

Folate: Names for “Foliage”

May be referred to as vitamin B9

Named for a chief source of folate: foliage or dark-green, leafy vegetables

Active form: folic acid, formed with vitamin C

Aids in metabolism of DNA, promotes chromosomal health, red blood cell formation

Helps prevent spina bifida if consumed in first few days after conception

Women of childbearing years advised to consume 400 mcg folate daily

Processed white-grain products are fortified with folate to lower the risk of infants born with spina bifida (a form of neural tube defect)


Vitamin b 12 cobalamin

Vitamin B12: Cobalamin

Important in DNA synthesis and may affect bone formation (Tucker et al., 2005)

Found in animal-based foods only; contains the mineral cobalt (hence the name cobalamin)

Deficiency causes irreversible nerve damage, megaloblastic anemia

Vitamin B12 supplementation may not be adequate; intramuscular B12 injections commonly provided for the elder population or persons with malabsorption (e.g., after gastric bypass surgery)


Vitamin c ascorbic acid water soluble derivative of glucose

Vitamin C (Ascorbic Acid): Water-Soluble Derivative of Glucose

First vitamin identified from experience of “limeys” (British sailors)—scurvy avoided by eating lemons (then called limes)

Scurvy = severe deficiency; mild deficiency related to bleeding gums and/or loose teeth, easy bruising, pedal edema, arthralgias (joint pain), and joint swelling

Acts as “glue” to hold body cells together

Promotes immunity and wound healing

Promotes bone growth, collagen, and growth of all body tissues

Serves as an antioxidant to reduce levels of free radicals (reactive oxygen species) for reduced risk of cellular damage

Found in fruits and vegetables only (e.g., leafy greens, citrus, melons, potato, green peppers, berries, tomatoes)


General functions of minerals

General Functions of Minerals

Serve as building materials and found in all body constituents

Bone and teeth (calcium, phosphorus)

Hair, nails, and skin (sulfur)

Blood (iron in hemoglobin)

Serve as regulators of body metabolism

Muscle contraction and relaxation (calcium, potassium)

Blood clotting (calcium)

Coenzymes (zinc, magnesium, potassium)


Calcium

Calcium

Chief mineral in bones and teeth

Allows for muscle contraction and function of nervous system and blood coagulation

Found in high amounts in milk, soybeans, bones (i.e., bones of salmon/anchovies), some leafy greens: collards, seaweed, hard water

Chief age for bone mineralization <35 years

Osteoporosis risk factors—low calcium and/or vitamin D intake, Caucasian or Asian heritage, low body weight, rheumatoid arthritis, steroids, smokers, alcohol abusers and alcoholics


Magnesium part of the chlorophyll molecule

Magnesium: Part of the Chlorophyll Molecule

Involved in strong bone formation

Critical to 300 metabolic enzymes

Regulates heartbeat, helps transport potassium and calcium, helps with muscle contractions, lowers inflammation

Involved in energy metabolism

Can serve as a calcium channel blocker (used to control hypertension and migraines)

Bound with chlorophyll (green leafy vegetables) and also found in milk, legumes, fish, eggs

Can be lost with diuretics and excess urination (as found with uncontrolled diabetes)


Phosphorus

Phosphorus

Helps enzymes act in energy metabolism

Only second to calcium in body content

Primarily found in bones

A ratio of 1.5 calcium to 1.0 phosphorus intake advised in early infancy to prevent tetany

Widely found in foods; added to carbonated beverages


Potassium

Potassium

Promotes regular heartbeat; altered levels contribute to irregular heart beat

A key “electrolyte” (related to electric flow)

Critical for intracellular enzyme functioning

Found in all foods; easy to obtain; very high amounts in green leafy vegetables, whole grains, milk, citrus fruits, bananas, potatoes, tomatoes

Excess avoided with kidney disease or use of ACE inhibitor Rx (avoid potassium chloride [KCl] in salt substitutes)


High potassium foods 500 mg

High Potassium Foods >500 mg

1 banana

1 cup tomato or orange juice

12 oz milk

1½ cups leafy green vegetables

1½ cups melon

1 cup beets

1 medium potato


Sodium

Sodium

Serves as an essential electrolyte

Found in salt as sodium chloride (Na+Cl-), minor amounts found in leafy green vegetables, milk, eggs, meat; very low amounts in fruits and unprocessed grains

1 teaspoon salt contains 2400 mg Na+

The Upper Limit (UL) of safety set at 2300 mg

The DASH diet (Dietary Approaches to Stop Hypertension) advocates restriction of 1500 mg

“No added salt” diet defined as less than 4000 mg Na+


Chloride

Chloride

Found in extracellular fluids and serves as an electrolyte

Found in gastric juice as part of hydrochloric acid

Deficiency found in conjunction with sodium depletion

Excess levels due to dehydration


Fluorine

Fluorine

Found in fluoride tablets and fluoridated water as used to promote strong teeth formation in children

Also found in fish, tea, and gelatin

Can be toxic and lead to mottling of teeth


Iodine

Iodine

Found in thyroid hormones and involved in general metabolism

Has an antioxidant function

Sea fish and seaweed naturally high in iodine; iodized salt is an important alternative source

Deficiency states: hypothyroidism, goiter (see slide)—linked with reduced IQ, and cretinism, a form of mental retardation, of infants born to women with iodine deficiency (now rare because of iodized salt use)

Excess intake leads to hyperthyroidism


Goiter caused by iodine deficiency

Goiter: Caused By Iodine Deficiency

Goiter. (From Swartz MH: Textbook of physical diagnosis: history and examination, ed 5, Philadelphia, 2006, Saunders.)


Chapter 3

Iron

Carries oxygen in red blood cells

Prevents iron-deficiency anemia

Heme—animal sources: especially liver, red meat; heme form readily absorbed

Nonheme—plant; need vitamin C source to convert to heme form for enhanced absorption

Iron frying pans are a source of iron, with long duration of cooking and acidic foods leading to highest iron absorption


Iron supplementation or fortified foods

Iron Supplementation or Fortified Foods

Advised for those with iron-deficiency anemia as determined with iron studies:

Percent iron saturation

TIBC (total iron-binding capacity)

Transferrin levels (a protein that transports iron)

Ferritin (storage form of iron)

With high-risk populations: pregnancy, growing children, women with menstrual cycle—related imbalances, malabsorptive conditions

Excess can cause hemochromatosis and lead to diabetes, liver, and heart damage; dx: transferrin index >1.0 (serum iron/transferrin)


Selenium

Selenium

An antioxidant mineral; helps prevent skin damage from sun exposure

Found in high amounts in Brazil nuts

Deficiency related to cardiomyopathy (a form of heart disease), loss of muscle strength(Beck et al., 2007), and found with a form of anemia(Semba et al., 2007)

Toxicity found with hair loss, defects of fingernails and toenails, anorexia, dermatitis, depression, organ damage, and central nervous system problems, including ataxia and respiratory disturbances(Kaprara and Krassas, 2006)


Chapter 3

Zinc

Critical for protein synthesis and cell division and function; part of 300 proteins; promotes stable DNA

Needed for bone growth, wound healing, immunity, sexual development, smell acuity, taste perception, promotes normal vitamin A levels

Part of 50 metabolic enzymes

Found in whole grains (germ), oysters, crabmeat, organ meats, brewer’s yeast

As a trace mineral, toxicity is possible; can lead to severe anemia due to low serum copper levels


Phytochemicals chemicals of life

Phytochemicals: “Chemicals of Life”

Vitamin-like substances recognized since the 1990s

Includes lutein (found in green leafy vegetables)

Lutein: essential to prevent macular degeneration

Includes lycopene (found in tomatoes)

Lycopene controls prostate tumors

Estimated 100 phytochemicals yet to be identified


Food preparation strategies to preserve vitamin and mineral content

Food Preparation Strategies to Preserve Vitamin and Mineral Content

Store fresh produce to avoid wilting and/or drying out

Cook foods in whole pieces, as possible, to decrease surface area for leaching of minerals into cooking water

Steam or microwave to reduce leaching of minerals

Cover open containers of juice to preserve vitamin C

Avoid excessive stirring while cooking to minimize exposure of vitamin C to air

Keep milk out of light to preserve vitamin B2 content


Fortification versus enrichment

Fortification Versus Enrichment

Fortify—make stronger (e.g., iron-fortified cereal)

Enrich—replace after removal by processing (e.g., enriched white bread with vitamins B1, B2, B3)


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