Chapter 9 vitamins and chapter 10 minerals

CHAPTER 9:VITAMINS

MEDICAL BIOCHEMISTRY

THE WONDERFUL WORLD OF VITAMINS/MINERALS/SUPPLEMENT

S

Pill pushers claim that supplements are necessary to guard your health, compensate for processed foods, enhance your athletic abilities, and promote future “super health”

WHAT ARE VITAMINS?

VITAMINS are essential organic substances needed in minute amounts by the body to perform specific metabolic functions

When a vitamin is synthesized from existing chemicals in the body the ingredient to make the conversion are called pro-vitamins (ex: carotine--Vit A.)

THERE IS NO DIFFERENCE OR ADVANTAGE BETWEEN

A VITAMIN OBTAINED NATURALLY FROM FOOD

AND A SYNTHETIC VITAMIN

ONLY 13 LEGITIMATE VITAMINS EXIST

• ORGANIC SUBSTANCES• REQUIRED FOR SPECIFIC METABOLIC

FUNCTION• NEEDED IN SMALL AMOUNTS

NON-VITAMINS

RUTIN (Lipoic Acid) Bioflavonoids (Vit P) Par-amino-benzoic acid

(PABA) Carnitine (Choline)

Where do Vitamins Come From?

All vitamins are found in green leaves and roots of plants except Vit B12 which is found only in animals

Man cannot synthesize Vit C and most of the fat soluble vitamins

VITAMIN ABSORPTION

FUNCTIONS OF VITAMINSFUNCTIONS OF VITAMINS essential links and regulators in metabolism tissue synthesis

TWO TYPES OF VITAMINS

FAT SOLUBLEFAT SOLUBLE- A (Retinol); D (Cholecaciferol); E

(Tocopherol); K (Menadione) WATER SOLUBLEWATER SOLUBLE

- C (Ascorbic Acid); B-complex- Thiamin, Riboflavin, Niacin, B-6, Pantothenic Acid, Biotin, Folacin, B-12

FAT SOLUBLE VITAMINS

A, D, E, K- Daily ingestion unnecessary, as

they are stored in the liver, fat cells and subcutaneously

- No mechanism to leave the body

- Can be toxic in excess

FAT SOLUBLE VITAMINSFAT SOLUBLE VITAMINS

VITAMIN DEFICIENCY EXCESSVit A night blindness headach, vomiting,

anorexia swelling

Vit D rickets vomiting, diarrhea

Vit E possible anemia relatively nontoxic

Vit K severe bleeding relatively nontoxic, jaundice

VITAMIN VITAMIN AACarotenoids

Functions- Source of vitamin A- Antioxidants- Other health benefits

Food Sources- Yellow-orange vegetables- Orange fruits- Dark-green leafy vegetables

Three biologically active molecules: retinol, retinal (retinaldehyde) and retinoic

acid.

R

Retinoic AcidRetinal

Retinol

ß-carotene

HC

HC

OOOOC

HC

H

ß-caroteneDioxygenaseß-carotene

DioxygenaseO2

Bile salts

O2

Bile salts

RetinaldehydeRetinaldehyde

RetinaldehydeRetinaldehyde

ß-carotene is Converted to Vitamin Aß-carotene is Converted to Vitamin A

Retinal is Reduced to Retinol

HCHC

OORetinaldehydeRetinaldehyde

RetinaldehydeReductase

RetinaldehydeReductase

NADPH (NADH) + H+

NADPH (NADH) + H+

NADP+ (NAD+)NADP+ (NAD+)

CH2OHCH2OHRetinolRetinol

Retinal can be Oxidized to Retinoic Acid

NAD, FAD

OHC

ORetinoic acid

(all-trans)

HCHC

OORetinaldehydeRetinaldehyde

Cells Dependent on Vitamin A

Skin Cornea Trachea Immunocytes

Bitot’s Spots

Bitot’s SpotsBitot’s Spots

Vitamin A in Food = Carotene + Vitamin A Esters

Hypervitaminosis A

Vitamin A (not carotenoids)

Liver damage Hemorrhage Coma Death

Vitamin A Teratogenesis

Associated with > 20% rate of spontaneous abortions and birth defects

13-cis-retinoic acid During first trimester Accutane

Anti-carcinogenic Properties of Vitamin A

Epidemiologic studies- Colon- Skin, breast, liver, prostate, & lung

Not replicated in basal diet separately or in combination

Other compounds in fruits & vegetables? Mechanism?

- Oxygen radical trap- A complements properties of E

VITAMIN VITAMIN EE A vitamin in search of a

disease!“no known evidence of dietary deficiency of vitamin E in humans”

Anti-oxidant effects- protects polyunsaturated fats and

vitamin A from destruction by oxygen

Vitamin E (TOCOPHEROLS)-The α-tocopherol molecule is the most potent of

the tocopherols. -is absorbed from the intestines packaged in

chylomicrons.- is delivered to the tissues via chylomicron

transport and then to the liver through chylomicron remnant uptake. The liver can export vitamin E in VLDLs.

- Due to its lipophilic nature, vitamin E accumulates in cellular membranes, fat deposits and other circulating lipoproteins.

- - The major site of vitamin E storage is in adipose tissue.

Vitamin E

Major Function:-Act as a natural antioxidant by scavenging free radicals and molecular oxygen. In particular vitamin E is important for preventing peroxidation of polyunsaturated membrane fatty acids. The vitamins E and C are interrelated in their antioxidant capabilities.

Sources and Absorption of Vitamin E

Vegetable oils Bile salts Pancreatic secretions Mixed micelles Chylomicrons

Clinical Significances of Vitamin E Deficiency

No major disease states have been found to be associated with vitamin E deficiency due to adequate levels in the average American diet. The major symptom of vitamin E deficiency in humans is an increase in red blood cell fragility. Since vitamin E is absorbed from the intestines in chylomicrons, any fat malabsorption diseases can lead to deficiencies in vitamin E intake.

Neurological disorders have been associated with vitamin E deficiencies associated with fat malabsorptive disorders.

Increased intake of vitamin E is recommended in premature infants fed formulas that are low in the vitamin as well as in persons consuming a diet high in polyunsaturated fatty acids.

Polyunsaturated fatty acids tend to form free radicals upon exposure to oxygen and this may lead to an increased risk of certain cancers.

Vitamin E

Progression of Neurologic Symptoms of Vitamin E Deficiency

Age intervals, YearAge intervals, Year0 2 4 6 8 10 12 14 160 2 4 6 8 10 12 14 16

+ 19 - 25% of patients+ 19 - 25% of patients + 25 - 75% of patients+ 25 - 75% of patients

+ 75 - 100% of patients+ 75 - 100% of patients

Hypoflexia or Areflexia

Truncal Ataxia

Limb Ataxia

Peripheral Neuropathy

Ophthalmoplegia

VITAMIN DVITAMIN D

Vitamin D is a steroid hormone that functions to regulate specific gene expression following interaction with its intracellular receptor.

VITAMIN DVITAMIN D

The biologically active form of the hormone is 1,25-dihydroxy vitamin D3 (1,25-(OH)2D3, also termed calcitriol).

Calcitriol functions primarily to regulate calcium and phosphorous homeostasis.

THE ROLE OF VITAMIN DTHE ROLE OF VITAMIN D Maintains plasma calcium &

phosphorous concentrations Supports cellular processes,

neuromuscular function, & bone ossification

Enhances calcium & phosphorous absorption from small intestine & mobilization from bone

VITAMIN DVITAMIN D

Exists as several lipids;

1) D3 - made in skin exposed to sunlight.

2) D2 - additive in fortified milk

Ergocalciferol (vitamin D2)

Cholecalciferol (vitamin D3)

Vitamin D Metabolism

Bone Mineral Content in Children w/ Cholestasis

Bone Mineral Content in Children w/ Cholestasis

Changes in Bone Mineral

Content

Changes in Bone Mineral

Content

Bowed Legs of Rickets

Rachitic Rosary

TOXICITY OF VITAMIN DTOXICITY OF VITAMIN D War-time supplementation

- 2,000 IU + 50 - 100 % more- Nutritional deprivation- Lack of sunlight

Epidemic of calcimia Some permanent brain damage Resultant laws in Europe

VITAMIN DVITAMIN D Deficiency

- Rickets in children- Osteomalacia and

osteoporosis in

adults Toxicity

- Hypercalcemia

VITAMIN KVITAMIN K Functions

- Blood clotting- Formation of bone

Food sources- Green vegetables, liver,

egg yolks

VITAMIN K (PVITAMIN K (Phylloquinone)

Hemorrhagic Disease of the Newborn

Intrauterine vitamin K deficiency Sterile intrauterine gut Why/how would Mother Nature let this

happen?

Water Soluble VitaminsWater Soluble Vitamins Transported throughout the

water medium of the body Not stored in the body

Deficiency of Water Deficiency of Water Soluble VitaminsSoluble Vitamins

Pathophysiology is result of reduced enzyme activities.

Multiple deficiencies are common. Diagnostic Challenge? To

recognize multiple findings.

Drugs may act as Vitamin Analogs (Media Serv)

Toxicity of Water Soluble Toxicity of Water Soluble VitaminsVitamins

Toxicity recapitulates deficiency if co-enzyme ≠ vitamin

Enzyme inactivation Thiamin, Riboflavin, Niacin,

Niacin, Pyridoxine, Folic acid Not Biotin or Vitamin C

Causes of Water Soluble Vitamin Deficiency

Decreased intake Decreased absorption

- Enhanced loss during enterohepatic circulation

Requirement- Pregnancy

Decreased Precursor- Inborn error of metabolism

B VitaminsB Vitamins

B vitamins act primarily as coenzymes

Work as catalysts Function in energy-

producing metabolic reactions

VITAMIN B1 (THIAMIN)VITAMIN B1 (THIAMIN) Functions

- Coenzyme in energy metabolism- Helps synthesize

neurotransmitters

Food sources- Whole and enriched grains- Pork, legumes, nuts, liver

Deficiency- Beriberi

VITAMIN B1 (THIAMIN)VITAMIN B1 (THIAMIN)

TPP-ATP Phosphoryltransferase

ThiamineThiamineThiamineThiamine TPPTPPTPPTPP

ATPATPATPATP

Thiamine-ATPThiamine-ATPPhosphoryl TransferasePhosphoryl TransferaseThiamine-ATPThiamine-ATPPhosphoryl TransferasePhosphoryl Transferase

TPPTPPTPPTPP

Clinical Significances of Thiamin Deficiency

The earliest symptoms of thiamin deficiency include constipation, appetite suppression, nausea as well as mental depression, peripheral neuropathy and fatigue.

Chronic thiamin deficiency leads to more severe neurological symptoms including ataxia, mental confusion and loss of eye coordination.

Other clinical symptoms of prolonged thiamin deficiency are related to cardiovascular and musculature defects.

The severe thiamin deficiency disease is known as Beriberi, is the result of a diet that is carbohydrate rich andt hiamindeficient.

An additional thiamin deficiency related disease is known as Wernicke-Korsakoff syndrome. This disease is most commonly found in chronic alcoholics due to their poor dietetic lifestyles. Wernicke-Korsakoff syndrome is characterized by acute encephalopathy followed by chronic impairment of short-term memory. Persons afflicted with Wernicke-Korsakoff syndrome appear to have an inborn error of metabolism that is clinically important only when the diet is inadequate in thiamin.

Dry BeriberiDry BeriberiDry BeriberiDry Beriberi

Wet BeriberiWet BeriberiWet BeriberiWet Beriberi

VITAMIN B2 (RIBOFLAVIN)VITAMIN B2 (RIBOFLAVIN)

Functions- Coenzyme in energy metabolism- Supports antioxidants

Food sources- Milk and dairy products- Whole and enriched grains

Deficiency- Ariboflavinosis


Riboflavin is the precursor for the coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).

The enzymes that require FMN or FAD as cofactors are termed flavoproteins.

Clinical Significances of Flavin Deficiency

Riboflavin deficiency is often seen in chronic alcoholics due to their poor dietetic habits.

Symptoms associated with riboflavin deficiency include itching and burning eyes, angular stomatitis and cheilosis (cracks and sores in the mouth and lips), bloodshot eyes, glossitis (inflammation of the tongue leading to purplish discoloration), seborrhea (dandruff, flaking skin on scalp and face), trembling, sluggishness, and photophobia (excessive light sensitivity).

Riboflavin decomposes when exposed to visible light.

VITAMIN B3 (NIACIN)VITAMIN B3 (NIACIN) Functions

- Coenzyme in energy metabolism- Supports fatty acid synthesis

Food sources- Whole and enriched grains- Meat, poultry, fish, nuts, and peanuts

Deficiency- Pellagra

Toxicity- High doses used to treat high blood cholesterol- Side effects: skin flushing, liver damage

VITAMIN B3 (NIACIN)VITAMIN B3 (NIACIN)

•Niacin (nicotinic acid and nicotinamide) is also known as vitamin B3. Both nicotinic acid and nicotinamide can serve as the dietary source of vitamin B3.

•Niacin is required for the synthesis of the active forms of vitamin B3, nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+). Both NAD+ and NADP+ function as cofactors for numerous dehydrogenases, e.g., lactate dehydrogenase and malate dehydrogenase.

NICOTINAMIDE AND NICOTINIC ACIDNICOTINAMIDE AND NICOTINIC ACID

Clinical Significances of Niacin and Nicotinic Acid

•A diet deficient in niacin (as well as tryptophan) leads to glossitis of the tongue (inflammation of the tongue leading to purplish discoloration), dermatitis, weight loss, diarrheAdepression and dementia. The severe symptoms, depression, dermatitis and diarrhea, are associated with the condition known as pellagra.

•Nicotinic acid (but not nicotinamide) when administered in pharmacological doses of 2–4 g/day lowers plasma cholesterol levels and has been shown to be a useful therapeutic for hypercholesterolemia. The major action of nicotinic acid in this capacity is a reduction in fatty acid mobilization from adipose tissue. Although nicotinic acid therapy lowers blood cholesterol it also causes a depletion of glycogen stores and fat reserves in skeletal and cardiac muscle.

Pellagra’s Dermatitis- HandPellagra’s Dermatitis- Hand

Pellagra’s Dermatitis- FootPellagra’s Dermatitis- Foot

Casal’s Necklace & Casal’s Necklace & Hyperpigmentation of Hyperpigmentation of Hands:Hands:Before & After Niacin Before & After Niacin TherapyTherapy

Pellagra GI & CNS

GI symptomsVomitingDiarrhea

CNS findingsDepression, insomnia, headaches, dizzinessProgression to limb rigidity, paresis, and fatal encephalopathy

VITAMIN B-6VITAMIN B-6 Pyridoxal, pyridoxamine and pyridoxine are

collectively known as vitamin B6.

All three compounds are efficiently converted to the biologically active form of vitamin B6, pyridoxal phosphate (PLP).

This conversion is catalyzed by the ATP requiring enzyme, pyridoxal kinase.

VITAMIN B-6VITAMIN B-6

Pyridoxine Pyridoxal Pyridoxamine


Pyridoxal Phosphate

VITAMIN B-6VITAMIN B-6 Pyridoxal phosphate functions as a cofactor in

enzymes involved in transamination reactions required for the synthesis and catabolism of the amino acids as well as in glycogenolysis as a cofactor for glycogen phosphorylase and as a co-factor for the synthesis of the inhibitory neurotransmitter γ-aminobutyric acid (GABA).

The requirement for vitamin B6 in the diet is proportional to the level of protein consumption ranging from 1.4–2.0 mg/day for a normal adult. During pregnancy and lactation the requirement for vitamin B6 increases approximately 0.6 mg/day.

VITAMIN B-6VITAMIN B-6 Deficiencies of vitamin B6 are rare and usually are

related to an overall deficiency of all the B-complex vitamins.

Other symptoms that may appear with deficiency in vitamin B6 include nervousness, insomnia, skin eruptions, loss of muscular control, anemia, mouth disorders, muscular weakness, dermatitis, arm and leg cramps, loss of hair, slow learning, and water retention.

VITAMIN B-6VITAMIN B-6 Functions

- Coenzyme in protein and amino acid metabolism

- Supports immune system Food sources

- Meat, fish, poultry, liver- Potatoes, bananas,

sunflower seeds Deficiency

- Microcytic hypochromic anemia Toxicity

- Can cause permanent nerve damage in high doses

VITAMIN B9 (FOLATE)VITAMIN B9 (FOLATE) Functions

- Coenzyme in DNA synthesis and cell division

- Needed for normal red blood cell synthesis

Food sources- Green leafy vegetables, orange juice,

legumes - Fortified cereals, enriched grains

VITAMIN B9 (FOLATE)VITAMIN B9 (FOLATE)

FOLATEFOLATE Deficiency

- Megaloblastic anemia- Can contribute to neural

tube defects- Women of childbearing age

need 400 micrograms/day of folic acid

Toxicity- Can mask vitamin B12

deficiency

CLINICAL SIGNIFICANCE OF CLINICAL SIGNIFICANCE OF FOLATEFOLATE

Folate deficiency results in complications nearly identical to those described for vitamin B12 deficiency.

The inability to synthesize DNA during erythrocyte maturation leads to abnormally large erythrocytes termed macrocytic anemia.

Certain drugs such as anticonvulsants and oral contraceptives can impair the absorption of folate.

VITAMIN B-12VITAMIN B-12Cobalamin is more commonly known as vitamin B12.

Vitamin B12 is composed of a complex tetrapyrrol ring structure (corrin ring) and a cobalt ion in the center.

Vitamin B12 is synthesized exclusively by microorganisms and is found in the liver of animals bound to protein as methycobalamin or 5‘deoxyadenosylcobalamin.


Functions- Needed for normal folate function

• DNA and red blood cell synthesis- Maintains myelin sheath around nerves

Food sources- Only animal foods: meats, liver, milk,

eggs Deficiency

- Pernicious anemia• Megaloblastic anemia + nerve damage

STRUCTURE OF VITAMIN B-12STRUCTURE OF VITAMIN B-12

CobalaminsCorrin ring contains central cobalt atom

Adenosylcobalamin Methylcobalamin


VITAMIN CVITAMIN C


Pernicious anemiaMegaloblastic anemiaNeuropathy: particularly degeneration of spinal cordUniversally fatalExtrinsic factor from liver

Patients were not producing enoughGastric acid to denature R proteinIntrinsic factor

VITAMIN CVITAMIN C Increases absorption of iron Influences serum cholesterol Affects immune system Affects synthesis of collagen Affects drug metabolism Protects DNA in sperm

VITAMIN C (cont)VITAMIN C (cont) Megadoses

- 1970 Linus Pauling - Vit C & common cold• recover more quickly

Possible effects of megadoses- Gout- Destruction of B vitamins- Breakdown of RBC

VITAMIN C (cont)VITAMIN C (cont)

Ascorbic Acid

VITAMIN C VITAMIN C Deficiency in vitamin C leads to the disease

scurvy due to the role of the vitamin in the post-translational modification of collagens. Scurvy is characterized by easily bruised skin, muscle fatigue, soft swollen gums, decreased wound healing and hemorrhaging, osteoporosis, and anemia.

Vitamin C is readily absorbed and so the primary cause of vitamin C deficiency is poor diet and/or an increased requirement. The primary physiological state leading to an increased requirement for vitamin C is severe stress (or trauma). This is due to a rapid depletion in the adrenal stores of the vitamin.

VITAMIN C (cont)VITAMIN C (cont)

CHAPTER 10 CHAPTER 10 MINERALSMINERALS

4% of the body’s mass is composed of 22 metallic minerals

Major and Minor MineralsMajor and Minor Minerals Minor Minerals

(< 100 mg/day)

- iron- zinc- copper- selenium- iodine- fluorine- chromium- molybdenum- manganese

Major Minerals (>100 mg/day)

- sodium- potassium- calcium- phosphorus- magnesium- sulfur- chlorine

• 4% of body mass consists of minerals

MineralsMinerals BIOAVAILABILITY

- HOW MUCH IS ABSORBED BY THE BODY• VITAMIN/MINERAL

INTERACTION

• FIBER/MINERAL INTERACTION

Where Do Minerals Come Where Do Minerals Come From?From?

Minerals occur freely in nature (rivers, lakes, oceans, topsoil, under earth’s surface

Minerals are found in root systems of plants and in the body structures of animals that consume plants and water

Best sources of minerals are animal products (because they are more concentrated in animal tissues than in plants)

Functions Functions of of

MineralsMinerals

Recommended Intake and Recommended Intake and Sources of MineralsSources of Minerals

Mineral supplements are generally not needed because most minerals are readily available in foods and the water supply

Exceptions include some geographic regions where the soil or water is deficient in a particular mineral- What regions are scarce in iodine?- What is iodized salt?- What is iron insufficiency?

-is required for the synthesis of the thyroid hormones

- plays an important role in the regulation of energy metabolism via thyroid hormone functions.

IODINE

Iodine- A major Deficiency Iodine- A major Deficiency Problem in the WorldProblem in the World

Swelling of thyroid gland known as goiter (iodine deficiency)

Hypothyroidism -lower metabolism, metal retardation, cretinism

20% of world pop is at risk

Goiter

Vitamin-Mineral Vitamin-Mineral InteractionsInteractions

There is synergism in consuming some minerals and vitamins together- Fe absorption is improved with

vitamin C (drink glass orange juice with Fe containing foods)

- Ca uptake is facilitated if Ca-rich foods are consumed with foods high in vitamin D

Fiber-Mineral InteractionsFiber-Mineral Interactions Consuming too much fiber (>35g daily)

decreases absorption of Ca, Zn, Mg, and Fe

These minerals become bound to dietary phytate and oxalate and are excreted in the urine and feces

What are phytate and oxalate? - fiberous compounds that bind minerals

• phytates found in coffee, grain fibers• oxalates found in chocolate, tea, coffee

CalciumCalcium The body’s most abundant mineral

(1.5 to 2.0% of body mass; 1400 g) Ca combines with P to form

hydroxyapatite, the crystalline structure of bones and teeth

Ionized, Ca serves these functions:• muscle contraction• transmission nerve impulses• activation of enzymes• blood clotting• fluid movement across membranes

What is Osteoporosis?What is Osteoporosis? When calcium is deficient, the bones

“give up” their Ca to try and restore the deficit. The bones literally become “hollow” or porous, leading to breaks and fractures

The hormone estrogen is linked to osteoporosis (because estrogen enhances Ca absorption; a decrease in estrogen no longer offers a protective effect)

OsteoporosisOsteoporosisBone Disease of Epidemic Bone Disease of Epidemic

ProportionsProportions 1.2 million fractures yearly 500,000 spinal fractures 230,000 hip fractures each year, 1.3 million osteoporetic women will

fracture one or more of their bones About 1 of 6 older men & 1 of 3 older women will

sustain hip fractures (death will occur in 20%) Often, x-rays don’t detect the disease until bone

loss reaches 30 to 50% of its total mineral content!

Progressive Progressive DiseaseDisease

30-50% bone loss by age 70 y

Shrinkage of spinal vertebrae

Who Gets the Disease?Who Gets the Disease? By age 50, men lose about 0.4% bone

each year; in women, the loss is about 0.8% starting at age 35 (double the loss 15 years sooner!)

During menopause, bone loss accelerates to between 1% to 3% each year. Thus, by age 60, a woman can lose about 15% of her bone mass, and by age 70, bone loss can be as much as 30%

Where Does The BoneWhere Does The BoneLoss Occur?Loss Occur?

Most occurs in the vertebrae (person shrinks in stature by up to 6 inches from age 45-50 to age 70).

The “spongy” bone (trabecular bone) loses its mineral content, causing the bone to crumble. The inside of the bone becomes honeycombed (like a beehive) and porous

Why is Dietary Calcium Why is Dietary Calcium Crucial?Crucial?

Shockingly, about 30% of college-age females consume only 400 to 500 mg of calcium daily (RDA = 1200 mg daily)

Calcium rich foods (dairy products) contain vitamin D and this increases Ca absorption into the bones

Adequate Ca intake, begun at an early age (6-14 years old), increases bone density

CALCIUM AND EXERCISE CALCIUM AND EXERCISE HELPSHELPS

1200 to 1500 mg Ca- sardines, pink salmon, ricotta cheese,

dried figs• calcium carbonate and calcium citrate can

help• meat, salt, coffee, alcohol inhibit Ca

absorption Exercise -weight bearing help

- weight training important for “bone fitness”

Sodium: How Much is Sodium: How Much is Enough?Enough?

is a key circulating electrolyte functions in the regulation of ATP-

dependent channels with potassium. These channels are referred to as

Na+/K+-ATPases and their primary function is in the transmission of nerve impulses in the brain.

Sodium: How Much is Sodium: How Much is Enough?Enough?

Excessive sodium intake increases fluid volume and peripheral vascular resistance- sodium-induced hypertension (occurs in 1/3 of

individuals with hypertension in U.S. and Japan) Recommended level = 1100 to 3300 mg/day

(average in U.S = 3000 to 7000 mg/day; amount actually needed = 500 mg/day)

Sodium plentiful in table salt, MSG, soy sauce, condiments, canned foods, baking soda, baking powder

Salt tablets for athletes?

IRONIRON

although considered a trace element, has a critical role in the transport of oxygen.

Iron is the functional center of the heme moiety found in each of the protein subunit of hemoglobin.

The function of iron is to coordinate the oxygen molecule into heme of hemoglobin so that it can be transported from the lungs to the tissues.

IRONIRON

IRONIRON 80% of Fe is heme (heme +

protein globin ---> hemoglobin Iron Deficiency Anemia - iron

isufficiency (low Hb - sluggishness, loss of appetite.

Inadequate Fe intake (30-50% of females Fe insufficient)

Other Functions of IronOther Functions of Iron Heme iron is an important component

of myoglobin, a storage and transport compound of oxygen within muscle cells (myoglobin contains about 5% of the body’s total iron stores)

Heme iron a constituent of cytochromes that aids energy transfer within mitochondria

Cytochromes transfer electrons (H+) during redox reactions in cellular respiration

Iron Deficiency AnemiaIron Deficiency Anemia Fact: Typical Western diet provides only 6

mg iron per 1000 calories of food intake Hemoglobin (Hb) reduced to low levels and

produces sluggishness, loss of appetite, reduced exercise capacity

Thus, a female who consumes 1700 kCal daily only consumes 10.2 mg iron daily

Recommended intake for females: 15 mg/d Recommended intake for males: 12 mg/d

Sports Anemia?Sports Anemia? Clinical anemia (12 g/100 ml

blood)

Fe loss is transient and occurs in early phase of training

Iron Status in FemalesIron Status in Females 30 to 50% of American women (young

children, teenagers, women of child-bearing age, and “athletes” are iron deficient

Consuming an additional 5 mg iron a day would would increase iron intake by 150 mg in one month. If 15-17% of this iron is absorbed, this would make an additional 15 to 25 mg available to help to counter the 5 to 45 mg iron loss during menstruation

Source of Iron ImportantSource of Iron Important Iron absorption varies depending on the source of

the iron (i.e., bioavailability depends on the source of the iron)

Vegetable sources: 2-20% of iron absorbed Animal sources: 10-35% of iron absorbed Are vegetarian athletes at risk for iron

insufficiency? What can you do to increase iron absorption?

- add foods rich in vitamin C to iron rich foods to increase their bioavailability.

- drink glass OJ with cereal; add sesame seeds to salad; add wheat germ to cereal. This produces 3-fold increase in nonheme iron absorption

Minerals and ExerciseMinerals and Exercise Sweat loss during exercise (1-5 kg

loss is common) - 1.5 - 8.0 g salt- Heat cramps - involuntary muscle

spasms

- Heat exhaustion - weak rapid pulse, low BP, headache, dizziness, sweating reduced

- Heat Stroke - sweating ceases, circulatory collapse, death

The energy content of a food is inversely related to it’s water content. What does this mean?

Foods high in water content are low in calories, and foods low in water content

are high in calories

Example: (cheese v watermelon)

WaterWater

calories

water

lo

hi cheese

melon

Foods High in Water ContentFoods High in Water Content(are low in calories)(are low in calories)

%Water kCal Lettuce 95.8% 3.7 Tomato, Squash, Pumpkin 93.7% 5.7 Cabbage 92.2% 6.5 Strawberries 91.5% 8.6 Watermelon 91.2% 8.9 Grapefruit 90.8% 9.1 Chocolate fudge 8.1% 115

Soft Drink Consumption Soft Drink Consumption in the United Statesin the United States

The average American consumes 1 gallon of soft drinks each week (52 gallons a year), or about 1 ton of soft drinks between the ages of 20 and 50!

One-third of soft drinks are diet drinks

Hydration TerminologyHydration Terminology Euhydration

- Normal daily water variation

Hyperhydration- Increased water content

Hypohydration- Decreased water content

Dehydration- Losing water

Rehydration- Gaining water

Body’s Water Compartments Intracellular fluid or ICF (62%) Extracellular fluid or ECF (38%)

- Blood plasma accounts for 20% of ECF (3 L)• When you sweat, the water comes from the blood

plasma (i.e., the ECF)• If you don’t replace the ECF volume by

consuming water on a regular basis, blood viscosity increases, placing a strain on cardiovascular function

• Other components of the ECF include lymph, saliva, fluids in eyes and joints, fluids secreted by glands, fluids in the intestines, fluids excreted by kidneys and skin, and fluids bathing nerves and spinal cord

Electrolytes and Body Electrolytes and Body WaterWater

ICF - low concentrations of Na+ and Cl-

- high concentrations of K+

ECF - high concentrations of Na+ and Cl- - low concentrations of K+

Water AbsorptionWater Absorption 2.0 Liters ingested daily

- Saliva, gastric secretions, bile and pancreatic and intestinal secretions contribute an additional 7 L each day

Of the 9 Liters ingested, not all is absorbed- Ingested solutions and foods (salt, AA,

sugar drinks) blunt water absorption

UrineUrine pH ranges between 4.5 to 8.0 High protein diets produce acidic urine CHO rich (vegetarian) diets produce

alkaline urine (is pH above or below 7.4?)

Color of urine produced by pigment urochrome, an end product of Hb breakdown

In disease states, smell of urine changes; fruity smell (acetone) in diabetes, and solutes in urine (glucose, RBC, WBC, proteins, bile pigments

Functions of Body WaterFunctions of Body Water Serves as body’s transport system Gas transport and gas exchange takes place

across moist surfaces Nutrients and gases are transported in

aqueous solution Waste products exit via urine and feces Water has heat stabilizing qualities (absorbs

large amounts of heat with minimal changes in Temp)

Fluids lubricate joints; prevents bone grinding Gives turgor to body tissues because water is

noncompressible

Water Balance -

No Exercise

Water Balance

with Exercise

Defend Against DehydrationDefend Against Dehydration Don’t remove “soaked” clothing—dry

clothes hinder evaporative cooling- Evaporation major physiologic defense- Evaporative loss of 1 L of sweat = 600

kCal of heat energy loss

Drink water regularly during physical activity, especially during events lasting 60 minutes or longer

What is the Primary What is the Primary Aim Aim

of Fluid of Fluid Replacement?Replacement?

To maintain To maintain plasma volume plasma volume so that circulation and so that circulation and sweating progress at sweating progress at

optimal levelsoptimal levels

Glucose PolymersGlucose Polymers What is a glucose polymer? (link of

10-15 glucose molecules) Sports drinks are popular because:

- low osmolarity (maltodextrins). Polymerized glucose solutions provide water and CHO at a faster rate than a drink of similar CHO content consisting of monosaccharides and disaccharides.

Generalized Summary:

Drink Cool Solutions, Drink Often, Choose the Brand Wisely

Gastric EmptyingGastric Emptying Fluids must be emptied from the

stomach before absorption in the small intestine.

Three factors influence gastric emptying:- Fluid temperature; cold water empties fastest

(41 degrees F)- Fluid volume; 8.5 oz every 15 min. Too much

slows gastric emptying- Fluid osmolarity; gastric emptying slowed when

fluid is concentrated >10%. Sugary solutions (4 - 8% should be goal for CHO concentration for exercise longer than 60 min)

Water Intoxication Water Intoxication (Hyponatremia(Hyponatremia))

Water intoxication refers to excessive water intake of more than 10 quarts a day

Causes significant dilution of the body’s normal sodium concentration

Symptoms include head-ach, blurred vision, excessive sweating, and vomiting. In severe cases, there is cerebral edema, convulsions, comatose, and death

Consume 400-600 ml (13 to 20 oz) about 10-20 minutes before performance

Exercise and HeatExercise and Heat Prevention is the most effective

way to control heat stress injuries- Acclimatization

- Water

- Salt

- Know when to exercise

Heat DisordersHeat DisordersHEAT CRAMPS

Cause: Prolonged exer in heat; negative NaSymptom: Tightening, cramps, low NaPrevent: Salt, acclimatization

HEAT EXHAUSTIONCause: Cumulative negative water lossSymptom: Exhaustion, hypohydration, flushed skinPrevent: Hydration before, during exercise

HEAT STROKECause: extreme hyperthermia, circulation failureSymptom: hyperpyrexia, lack of sweat, neurologic failure

Prevent: Acclimatization, water, minerals, no exercise

Activity And HeatActivity And Heat

ACSM Position Stand: Exercise and Fluid Replacement

1. Primary objective for replacing body fluid loss during exercise is to maintain normal hydration.

2. Important to consume adequate fluids during the 24-h period before an event and drink about 500 ml (about 17 0z) of fluid about 2 h before exercise to promote adequate hydration and allow time for excretion of excess ingested water.

3. To minimize risk of thermal injury and impairment of exercise performance during exercise, fluid replacement should attempt to equal fluid loss.

4. At equal exercise intensity, the requirement for fluid replacement becomes greater with increased sweating during environmental thermal stress.

5. During exercise lasting longer than 1 h, it is important to do the following:a. add CHO to the fluid replacement solution to maintain blood glucose concentration and delay the onset of fatigue

b. electrolytes (primarily NaCl; ) should be added to the fluid replacement solution to enhance palatability and reduce the probability for development of hyponatremia.

c. During exercise fluid and CHO requirements can be met simultaneously by ingesting 600-1200 ml/hr of solutions containing 4% to 8% CHO.

d. During exercise greater than 1 h, approximately 0.5 to 0.7 g of sodium per liter of water would be appropriate to replace that lost from sweating.

Water Loss and

Temperature

SUPPLEMENTS&

ERGOGENIC AIDS

Ergogenic-“tending to increase work”

An ergogenic aid is defined as “.. A physical, mechanical, nutritional, psychological, or pharmacological substance or treatment that either directly improves physiological variables associated with exercise performance or removes subjective restraints which may limit physiological capacity”

Nutritional Ergogenic Aids

• Caffeine Glycerol • Carnitine Phosphate

• Sodium Bicarbonate • Dichloroacetate

• Creatine • Branched chain amino acids

Examples of Ergogenic Aids• Warm-up • Caffeine ingestion • Carbohydrate ingestion• Liquid ingestion • Glycerol ingestion • Phosphate ingestion • • • Creatine ingestion • Blood doping • NaHCO3

- ingestion• Erythropoietin • Growth hormone • Testosterone

Nutritional Herbs/Supplements

During the last decade, the use of herbs as nutritional supplements has expanded significantly. Thus, knowledge of herbs, their purported beneficial effects, and possible negative side effects takes on added importance for athlete and others contemplating their use.

HERBAL AGENTSCommonly used herbal compounds

- Astragalus (Huang qi)- Bilberry (Vaccinium myrtillus) - Bee Pollen (Buckwheat pollen; Puhuang)- Chamomile - Echinacea (Echinacea purpurea)- Ephedra - Garlic (Allium sativum)- Ginseng, Asian (Pannax)- Ginseng, Siberian (Eleuthero Root)- Ginkgo Biloba (Maindenhair tree)

Commonly used herbal compounds (cont)Guarna (Paullinia cupana)Kava Kava (Piper methysticum)Milk Thistle (Silbum marianum)Glucosamine SulfateGrape Seed ExtractSaw Palmetto (Serenoa repens)St. John’s Wort (Hypericum perforatum)Witch Hazel (Hamamelis virginiana)YohimbeValerian

HERBAL AGENTS

Anabolic Steroids Structure and action

- Sterol structure similar to testosterone- Promotes protein synthesis

Stacking - Combining multiple steroid

preparations in oral & injectable form Pyramiding

- Progressively increasing the dosage

Anabolic Steroids Drug with a considerable

following- Its becoming increasingly popular

with more than just strength athletes

Effectiveness- Dosage is an important factor- Training volume accompanying

use

Changes from baseline in average FFM, muscle, fat, and strength over 10-wks of testosterone treatment

Examples of oral and injectable anabolic steroidsGeneric Name Commerical

NameForm Retail $ Black

Market $

OxymetholoneOxandroloneStanazololNandroloneDeconateAndrolone-D200

Anadrol-50OxandrinWinstrol VDurabolinDeca-DurabolinNeo-durabolic

Oral: 50 mgOral; 2.5 mgOral; 2 mgInject; 25 mg/mlInject; 25 mg/mlInject; 50 mg/ml

$115/100 tabs$420/100 tabs$100/100 tabs$275/ml vial$12/2 ml vial$12/2 ml vial

$200-500$600-1600$200-500$200-500$400-750$450-750

Life-shortening Effects of Exogenous Steroids Use in Mice

Anabolic Steroids Side effects and medical risks

• Cystic acne, “road rage,” peliosis hepatis, increased plasma lipoproteins

• In males: testicular atrophy & gynecomastia• In females: clitoral enlargement, squaring of the

jaw, lowering of voice

• ACSM Position Statement on Anabolic Steroids

Growth Hormone Genetic engineering comes to sports

- Human growth hormone• Produced in the Pituitary gland• Stimulates bone & cartilage growth• Enhances fatty acid oxidation• Reduces glucose & amino acid breakdown

- Excess GH may result in:• Gigantism• Acromegaly

- No unanimity among researchers

DHEA: A Worrisome Trend DHEA- Dehydroepiandersterone

- Steroid hormone produced by the adrenal glands Claims for DHEA

• Testosterone booster• Bolsters immune system• Preserves youth• Decreases fatigue & joint pain• Slows aging• Invigorates sex life

- An unregulated compound with uncertain safety

Androstenedione Claims:

- Stimulates production of endogenous testoterone

- Enables one to train harder- Increases muscle mass- Aids healing/recovery process

Research shows no effect of supplementation on basal serum testosterone or any training response in terms of muscle size & strength

Amino Acid Supplements for an Anabolic Effect

Claims:Boost body’s natural production of:- Testosterone- Growth hormone- Insulin-like Growth Factor – 1

Resulting in an increase in muscle mass and a reduction in fat mass

Creatine Supplement form - creatine monohydrate

- Important component of high-energy phosphates- Documented benefits in humans

• Improved muscular strength and power• Enables heavier lifting for greater overload

- Creatine loading• 20 –25 g/day

- Some research shows no benefit

Amino Acid Supplements

Stimulating an anabolic effectConsuming carbohydrate and/or protein immediately after resistance training may augment hormonal response to the training

Branched Chain Amino Acids

The main BCAA’s are leucine, isoleucine, and valine. These amino acids decrease the ability for tryptophan to cross the blood brain barrier, impeding the formation of seratonin and the perception of fatigue (central fatigue).

CaffeineImproved exercise

endurance

Stimulant to CNS

Diuresis

Incidence of cardiac arrythmias

Muscle glycogenolysis

Lipolysis

Caffeine• The most highly consumed drug in North America

and Europe

• IOC initially banned caffeine in 1962, then removed from list in 1972

• Today, urinary caffeine > 12 mg/L is an IOC infringement

• This urinary level requires > 13.5 mg/kg caffeine, where 1 cup coffee provides 80 mg

1012 mg/80 = 12.7 cups 330 mg/80 = 4.1 cups

(Assume 75 kg BW)

IOC banned dosage Ergogenic benefit

Warning About Caffeine Possible side effects:

• Nervous irritability

• Muscle twitching

• Psychomotor agitation

• Elevated HR & blood pressure

• Increased occurrence of PVCs

• Insomnia

Caffeine produced significantly faster split times

Effects of caffeine on high-intensity exercise results from facilitated use of fat as an exericse fuel, thus sparing CHO reserves

Chapter 9 vitamins and chapter 10 minerals

Health & Medicine

Transcript of Chapter 9 vitamins and chapter 10 minerals