micronutrients 2008

7/29/2019 Micronutrients 2008

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Victor Tambunan

Fiastuti Witjaksono

Erwin ChristiantoDepartment of Nutrition

Faculty of MedicineUniversitas Indonesia


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References

Mahan LK, Escott-Stump S. Food & Diet Therapy12th ed., 2008

Gropper SS, et al.Advanced Nutrition and

Human Metabolism4th ed., 2005

Shils ME, et al. Modern Nutrition in Health

and Disease10th ed., 2006

Bowman BA, Russell RM. Present Knowledge in

Nutrition9th ed., 2006


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Organic substances

Needed in small amounts Function in specific metabolic processes

Maintain health & secure growth

Should come from diet (plants & animals)


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Natural vs. Synthetic Vitamins

Chemically identical

Bioavailability same

Bioavailability:the degree to which a substance becomesavailable to the target tissue
http://bariatricwellness.net/images/07092005_tablets.jpg


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Megadoses Vitamin

a dose at least 10 times greater than

the recommended intake

Seldom obtained from food alone

Readily available in pills


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Fat soluble:

Vitamins A, D, E, and K

Water soluble:

Vitamins B group and C


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Fat Soluble Water Soluble

Soluble in fat

Excess intake need to bestored

Excreted in urine & bile(little)

Deficiency symptomsslow to develop

Not absolutely necessaryin diet every day

Have precursor

Soluble in water

Minimal storage of dietaryexcesses

Excreted in urine

Deficiency symptomsoften develop rapidly

Must be supply in dietevery day

Do not have precursor


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THIAMIN

Functions

Thiamin pyrophosphate (thiamin

diphosphate, cocarboxylase):coenzyme in energy metabolism &

transketolation (HMP shunt)

Involve in the production & release of

acetylcholine


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Piruvate acetyl-CoA

NAD+ NADH + H+

CoA CO2

TPP

FAD

Glucose

Citric acidcycle

TPP: thiamin pyrophosphateFAD: flavin adenine dinucleotideNAD: niacin adenine dinucleotide

Oxidation of glucose

Oxidative decarboxylation


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Deficiency symptoms

Wet beri-beri: edema, cor bovinum

Dry beri-beri: paresthesia Infantile beri-beri: 25 months of age

Cerebral:

in alcoholism

Wernicke-Korsakoff syndrome


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Food Sources

Organ meats (liver, kidney, etc.)

Legumes

Whole-grain and enriched cereals &breads

Wheat germ

Potatoes


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RIBOFLAVIN

Functions

Part of two coenzymes: Flavin mono-nucleotide (FMN)

Flavin adenine dinucleotide (FAD)

Coenzyme in energy production fromoxidation of glucose, fatty acids, andamino acids


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Fatty acyl-CoA

acetyl-CoA

FAD

FADH2

NAD

NAD + H+

Citric acidcycle FAD: flavin adenine dinucleotide

NAD: niacin adenine dinucleotide


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Deficiency

Stomatitis angularis

Seborrheic dermatitis Cheilosis

Glossitis (magenta tongue)
http://www.aids-images.ch/slides/346,700,600,0,0.jpg


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Food Sources

Milk and dairy foods

Organ meats

Green leafy vegetables

Eggs

Enriched cereals and breads


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NIACIN

Nicotinic acid, nicotinamide

Can be synthesised from tryptophan

Function

Coenzymes:NADH, NADPH in carbohydrates, fattyacids, and amino acids metabolism


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Deficiency

Pellagra ---- 4 Ds (diarrhea, dermatitis,

dementia, and death) Tremors

Sore tongue (beef tongue)

Low blood or urine nicotinamide


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Food Sources

Fish

Liver

Meat Poultry

Milk

Eggs

Many grains

Peanuts

Legumes


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VITAMIN B6

Forms: pyridoxine, pyridoxal, pyridoxamine

Functions

Coenzyme pyridoxal phosphate (PLP)

in amino acid metabolism (transamination)

Synthesis ofneurotransmitters:

Serotonin Norepinephrine

Epinephrine g-amino butyric acid (GABA)

Synthesis of heme


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a-keto acid 1

Amino acid 1 a-keto acid 2

Amino acid 2

PLP

Transamination

PLP: pyridoxal phosphate


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Deficiency symptoms

Anemia Impaired cell-mediated immunity

Niacin deficiency

Glossitis, cheilosis, stomatitis

Seborrheic dermatitis

Deficiency may be precipitated by medicationse. g. antituberculosis drug, isoniazid (INH)

Tryptophan Niacin

PLP


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Food Sources

Chicken

Liver

Fish Egg yolks

Whole grain cereals

Potato Banana


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FOLIC ACID

Functions

Biosynthesis of purine & pyrimidine

Synthesis of the amino acidsmethionine, histidine, and serine

Formation of heme

Catabolism of histidine


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Deficiency symptoms

Megaloblastic anemia

Glossitis

GI disturbances

General weakness

Neural tube defects (NTD)


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Food Sources

Asparagus

Spinach

Wheat germ

Yeast

Legumes

Nuts

Liver

Kidney
http://cherryclafoutis.files.wordpress.com/2007/04/asparagus.jpghttp://www.urbanext.uiuc.edu/veggies/images/spinach.jpg


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VITAMIN B12

Functions

DNA synthesis Growth & cell division

Coenzyme: homocysteine methionine Metabolism of propionate, amino acids,

and single carbon (C)


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FH4: tetrahydrofolateSAM: S-adenosyl methionineCH3: methylPLP: pyridoxal phosphate


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Deficiency

Pernicious anemia

Enlarge bone marrow cells (megaloblastic)

Neurologic disorders

Hyperhomocysteinemia

Can develop in vegans (true vegetarians)

coronary heart disease risk


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Food Sources

Liver

Kidney

Milk & dairy foods

Meat

Eggs


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MINERAL

Inorganic substances, essential

Vital to maintain life, growth, & reproduction

Balance among them is crucial for health

Ash constituents when food is burned

4% of human body, includes 60 minerals

Exist as free ion or bound


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Macronutrient minerals (majorminerals):

required in the diet in relatively largeamounts

Micronutrient minerals (traceelements):

required in relatively small amounts


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Minerals essential for human nutrition

Calcium (Ca)

Phosphorous (P)

Potassium (K)Sulfur (S)

Sodium (Na)

Chloride (Cl)

Magnesium (Mg)

Iron (Fe)

Zinc (Zn)

Copper (Cu)Iodine (I)

Selenium (Se)

Manganese (Mn)

Chromium (Cr)

Molybdenum (Mo)

Cobalt (Co)

Major minerals Trace elements


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1. Components of essential body compounds

2. Cofactors in biological reactions

3. Facilitation of absorption, digestion, & transport

4. Maintenance of acid-base balance

5. Maintenance of water balance

6. Transmission of nerve impulses

7. Regulation of muscle contraction

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General Functions


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The most abundant mineral in the body

Functions Bone & tooth formation

Growth

Blood clotting

Influences many biochemical reactions


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Functions (cont.)

Ca is required for nerve transmission & regulationofheart muscle function

Second messenger in signal transductionsCa2+ is an integral part of the signaling systems

facilatated by calmodulin

Calmodulin:an intracellular calcium-dependent regulatoryprotein (Ca2+ receptor protein)


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Food Sources

Milk and milk products

Sardines

Clams

Oysters

Green leafy vegetables

Tofu
http://www.urbanext.uiuc.edu/veggies/images/spinach.jpg


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Functions

Mineralisation of bones & teeth

Energy released in CHOs, fats & proteinsoxidation adenosine triphosphate (ATP)

Integral part of DNA & RNA

Component of essential body compounds:

coenzyme thiamin pyrophosphate (TPP)


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Food Sources

Meat

Poultry Fish Eggs Milk & milk products Cereals Legumes Nuts

In general, good food sources ofprotein are alsogood sources ofP


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Major cation of intracellular fluid

Functions

Required:

For cell growth

In biochemical reactions, esp. those involvedin the release of energy from food

In the synthesis of glycogen & protein


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Food Sources

Fruits (especially banana)

Milk

Meat

Cereals

Vegetables

Legumes


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Stabilise the structure of ATP in ATP-dependent

enzyme reactions Cofactor for >300 enzymes involved in the

metabolism of food components & synthesis ofmetabolic products:

e.g. - Synthesis of fatty acids & proteins- Phosphorylation of glucose

Muscle relaxation

Functions


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Glucose Glucose 6-phosphate

ATP ADP

Mg2+

HEXOKINASE

GLUCOKINASE

Phosphorylation of glucose


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Food Sources

Nuts

Legumes

Cereals

Dark green vegetables

Milk

Tofu


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Functional Iron

Hemoglobin Myoglobin

Heme enzymes

Nonheme enzymes

Nonfunctional Iron

Iron storage compoundswithin the liver, spleen, &bone marrow:

Ferritin

Hemosiderin Transferrin


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Functions

Oxygen transport

Cofactor of enzymes:

Involved in energy release during nutrients oxidation

Conversion ofb-carotene retinol

Synthesis of purine, carnitine, collagen,neurotransmitters dopamine, serotonin, & norepinephrine

Formation of erythrocytes


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Citric acid cycle(Krebs cycle)


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Deficiencies

Anemia Low productivity

Low cognitive function

Prone to infection Body temperature regulation is disturbed

Excess

Hemosiderosis (liver)

Hemochromatosis (other tissues)
http://www.pathconsultddx.com/images/S1559867506708336/mmc2-sml.jpg


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Heme iron Iron that is combined

within heme groups

Largely derived fromhemoglobin & myoglobinmolecules within foods ofanimal origin

Absorbed 25% of dietary

iron

Nonheme iron Iron that is not bound within

the structure of heme

Found predominantly inplant foods

Absorbed only 5%

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Heme iron has higher bioavailability than nonheme iron


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Food Sources

Liver

Meat

Egg yolk

Legumes

Dark green vegetables

Shrimp

Oysters

Milk & milk products are devoid of iron
http://www.math.pitt.edu/~bard/bardware/popeye/spinach.gif


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Catalytic functions:

required for the biological function of >300 enzymes(zinc metalloenzymes) e.g. RNA polymerases, alkalinephosphatase, & carbonic anhydrase

Normal growth, reproduction, & immune system

Taste buds healthy appetite

Involved in stabilisation of protein & nucleic acidstructure

Functions


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Structural functions:

in structural zinc sites, or zinc fingers,

Zn2+ is coordinated by 4 amino acid side chains.

Linking of zinc fingers to corresponding sites on DNA

initiates the transcription process

& gene expression

O2

- H2O

2

SOD

(superoxide) (peroxide)

C, Cys: cysteineH, His: histidine

Antioxidant: constituent of superoxide dismutase (SOD)


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Deficiencies

Growth retardation Delayed wound healing Delayed sexual maturation Immune deficiencies Hypogonadism Impaired taste

& hypospermia (hypogeusia)

Skin lesions

Patients with type 1 & 2 diabetes:

hyperzincuria tends to with the severity of the disease


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Food Sources

Oysters & shellfish

Fish

Meat

Liver

Legumes

Milk

Wheat bran


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Roles in mitochondrial in energy production

involve in Cu-containing electron transportprotein

Part of Cu-containing enzyme SOD

Promotes synthesis of melanin & catecholaminesCu in ceruloplasmin role in oxidising iron

Synthesis of collagen & elastin

Functions


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Respiratory chain components in mitochondria


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Deficiency

Anemia

Neutropenia

Skeletal demineralisation

Hair & skin depigmentation Failure of erythropoiesis

Menkes syndrome(kinky-hair syndrome): hereditary.

Affected infants: retarded growth, defective hair

keratinisation & pigmentation, hypothermia,degenerative changes in aortic elastin, &progressive mental deterioration


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Food Sources

Shellfish Liver, kidney Meats

Chocolate Nuts Cereal grains Dried legumes Dried fruits

Cows milk: poor source of Cu


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Synthesis of triiodothyronine (T3) & thyroxine (T4)

Conversion of T4 T3, catalysed by Se-containing5-deiodinases

The metabolic action is through T3 in tissues

Thyroid hormones promote synthesis of enzymes & otherproteins to metabolic activity in tissues Thyroid hormones is essential for proper maturation of

the central nervous system (CNS)

Functions


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Deficiencies

Fetal & infant mortality

Neurologic deficit Cretinism: mental retardation, hearing & speech loss,

short stature, and spasticity

Intellectual impairment low IQ Reproductive damage

Hypothyroidism Goiter enlargement of thyroid gland

Less energetic & inefficient


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Food Sources

Iodized table salt

Seafoods: clams, lobsters, oysters,

sardines & other saltwater fish

The iodine content of cows milk&eggs isdetermined by the iodides in the diet of the animal

The iodides content in ofvegetables varies accordingto the iodine content of the soil


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Antioxidant: integral part of glutathioneperoxidase (GSHPx) break down H2O2

Constituent of the enzyme 5-deiodinases which

convert T4 (thyroxine) T3 (triiodothyronine)T3 is the active thyroid hormone

Functions


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2GSH

GSSG

H202

2H20

Se Glutathioneperoxidase

Enzymatic reaction catalysed by Se-containingenzyme, glutathione peroxidase (GSHPx)

GSH: reduced glutathioneGSSG: oxidised glutathione


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Deficiency

Keshan disease

cardiomyopathy in children

Kashin-Beck disease

preadolescent or adolescent osteoarthritis


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Food Sources

Brazil nuts Seafood

Kidney

Liver Meat

Poultry

Grains

Selenium content in food depends on Se contentin the soil &water


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Component of many enzymes, including: Enzyme in energy release metabolism Mitochondrial SOD Enzymes in CHO & lipid metabolism

Functions

Mn is associated with: Formation of connective & skeletal tissues Growth & reproduction


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Citric acid cycle(Krebs cycle)


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Food Sources

Blueberries

Whole grains

Legumes

Nuts

Tea

Fruit


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Potentiates insulin action influencesCHO, lipid, & protein metabolism

Functions

Deficiency

Insulin resistance & a few lipid abnormalities
http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2003/Williford/picturefrombook/Slide2.JPG


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Food Sources

Brewers yeast

Broccoli

Oyster

Liver

Potatoes

Whole grains

Chicken Bran

Fatty acids Amino acidsGlucose
http://www.dkimages.com/discover/previews/743/115919.JPG


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CO2 + H2O + Energy

Citric acid cycle

NiacinPotassium

Magnesium

RiboflavinNiacin

SulfurMagnesium

Vitamin B6Magnesium

Potassium

NiacinThiamin

Riboflavin

ManganeseIronMagnesiumCopper


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Recommended Dietary Allowances

(RDA)

Indonesian RDA:

Angka Kecukupan Gizi(AKG) 2004


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