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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
VITAMIN B2 (RIBOFLAVIN)VITAMIN B2 (RIBOFLAVIN)
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.
VITAMIN B2 (RIBOFLAVIN)VITAMIN B2 (RIBOFLAVIN)
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
VITAMIN B-6VITAMIN B-6
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.
VITAMIN B-12VITAMIN B-12
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 B-12VITAMIN B-12
VITAMIN CVITAMIN C
VITAMIN B-12VITAMIN B-12
VITAMIN B-12VITAMIN B-12
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
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