Nutrition
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Nutritional terms:
Nutrition: is the science of food and the nutrients and other substances they contain,and of
their actions within the body (including ingestion, digestion, absorption, transport,
metabolism,and excretion).
Foods : product derived from plants or animals that can be taken into the body to yield energy
and nutrients for the maintenance of life and the growth and repair of tissues.
Nutrients : chemical substances obtained from food and use in the body to provide energy,
structural materials, and regulating agents to support growth , maintenance, and repair of the
body's tissues.
Nutrient can be divided in to:
1.Macronutrients: these are fat , protein , & carbohydrate which make the majority of our food.
2.Micronutrients: like vitamins and minerals , they so called because they required in very
small amounts.
Essential nutrients: nutrients that must be obtained from food because the body cannot make
them for itself in sufficient quality to meet biological needs.
Calories : unite by which energy is measured. Food energy is measured in kilocalories.(1000
calories equal 1 kilocalories).
Requirement : the lowest continuing intake of a nutrient that will maintain a specified
criterion of adequacy.
Deficient : the amount of a nutrient below which almost all healthy people can be expected
,over time, to experience deficiency symptoms.
Primary deficiency: a nutrient deficiency caused by inadequate dietary
intake of a nutrient.
Secondary deficiency: a nutrient deficiency caused by some thing other than an inadequate
dietary intake such as disease condition or drug interaction that reduce absorption, accelerates
use, or destroy the nutrients.
Nutritional assessment: a comprehensive analysis of a person nutritional status
Malnutrition : any condition caused by excess or deficient food energy or nutrient intake or by
an imbalance of nutrients.(mal=bad)
Under nutrition: deficient energy or nutrients.
Over nutrition: excess energy or nutrients.
Food guide pyramid :
It is a nutritional education guide , composed of 6 nutritional groups arranged in 4 levels inside
the pyramid starting from bottom up to the head.
1.bread , cereal, rice &pasta group
Number of servings 6-11 servings of bread or 4 spoons of rice or pasta (100 gram).
2.fruit group
One serving represent one apple or banana or any fruit according to the season (2-3 serving)
3.vegetable group
3-5 servings = (180-220 gm), each serving represent one cup of leafy vegetable or half cup of
sliced vegetable or 3/4 cup of juce.
4.meat group
3-5 servings , one serving represent 30 gm of meat , or one egg or 1/8 of medium sized chicken
, or 1/2 cup of cooked legumes.
5.milk group
3-5 servings, serving measured by cup and it is equal to 2-3 cups of milk daily or the same
amount of yogurt or 2-3 pieces of cheese.
6.fat, oil, sweets : use sparingly.
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Classification of foods:
There are many classification according to different criteria.
1.classification by origin
a. foods of animal origin
b. foods of plant origin
2. classification by chemical composition
Proteins , carbohydrates , fats , minerals , and vitamins
3. classification by predominant function
a. body building foods(milk, meat, fish, poultry)
b.energy giving foods (cereals, sugar , fat & oils)
c.protective foods ( vegetables ,fruit , milk)
4.classification by nutritive value
Cereals , legumes , fruits , vegetables , fat , oil
Proteins
It is a vital structural and working substances , composed of carbon , hydrogen , oxygen , and
nitrogen atoms arranged in to amino acids linked in a chain.there are 20 a.a , 9 of which the
body can not make; they are essential (Leucine , isoleucine , lycine,……).
Protein divided according to their content to essential a.a , they divided in to:
1.high quality protein: dietary proteins containing all the essential amino acids in relatively the
same amounts that human being require. They may also contain non essential a.a.
2.low quality protein : proteins that lack one or more of the essential.
In some cases one low quality protein can provide the essential a.a that the other lacks , when
this occurs that proteins are called complementary proteins.
Protein digestion and absorption : see the figure
Protein metabolism
Protein turnover and nitrogen balance go hand in hand , in healthy adults protein synthesis
balance with degradation and protein intake from food balances with nitrogen excretion in the
urine , feces and sweat. When nitrogen intake equal to nitrogen out put , the person is nitrogen
equilibrium or zero nitrogen balance.
If the body synthesis more protein than it degrades and add protein , nitrogen status become
positive. Nitrogen status is positive in infants , children , adolescent, and pregnant woman.
If the body degrades more than it synthesizes and loses protein , nitrogen status become
negative .nitrogen status is negative in people who are starving or suffer from other sever
stresses e.g burn , injuries , infections and fever , the body loses nitrogen as it breaks down
muscle and body proteins for energy.
Source :
1.animal source: meat, fish, poultry , cheese , eggs , yogurt , and milk. Animal source provide
high quality protein.
2.plant source : vegetable , nuts , seeds , grains , and legumes.proteins from plants tend to be
limiting one or more essential a.a .
Functions:
1.growth and maintenance , protein support the growth & repair of body tissues.
2. most enzymes and hormones are proteins in nature , so they facilitate chemical reactions
&regulate body process.
3.protein help to maintain acid-base balance of body fluids by acting as buffers.
4.help in production of antibodies that in activate foreign antigens so protecting the body
against disease.
5.provide energy when dietary CHO & fat is insufficient.
Daily requirement of protein is 1gm /Kg/day , extra proteins required in growing children ,
pregnancy , lactation , elderly , after surgery , sever burns , and during infection.
Carbohydrates (CHO)
Compounds composed of carbon , oxygen and hydrogen , that classified according to their
chemical composition in to:
1.simple CHO (SUGARS)
2.complex CHO .
simple CHO: include
a. monosacchride – single sugars which include:
glucose (blood sugar), fructose (fruit sugar) , galactose(found in milk).
The 3 monosacchride are important in nutrition , all have the same numbers and kinds of atoms
but different in structure.
b.disacchride –sugars composed of pairs of monosacchrides, each containing a glucose paired
with one of the three monosacchrides.
Sucrose (glucose +fructose), Lactose (glucose +galactose ) , maltose(glucose + glucose )
complex CHO: also called polysaccharide (composed of many monosacchrides linked
together) , include: starches , glycogen , and fibers.
1. glycogen: an animal polysaccharide composed of glucose , manufactured and stored in liver
and muscles as a storage form of glucose.
2.starches: plant polysaccharide composed of glucose, so when eat starch it will hydrolyzed in
to glucose and uses it as source of energy.
3.fibers: are the structural parts of plants and thus are found in all plant derived foodsvegetables, fruits, whole grains, and legumes. Diatary fibers differ from starches in that the
bonds between their monosacchrides cannot be broken down by digestive enzymes in the body
for this reason diatary fibers are often called non starch polysacchrides.
Source : fruit , honey , syrups , white sugar , vegetables , milk and milk products , grains ,
potatoes.
Daily requirements:
Minimum is 50-100 g/day ,it is recommended that half of one energy req. should be come from
CHO.
The body break down starches in to the disaccharide maltose , maltose and other disaccharide
(lactose & sucrose) are broken in to monosaccharide. Then monosacch.are convert mostly to
glucose to provide energy for cells' work. The fibers help to regulate the passage of foods
through GIT system .(see the figure)
FUNCTIONS
1.CHO regarded as a main source of energy , providing 4 kcals per gram.
2.CHO is essential for oxidation of fats .
3.as CHO provide the body by energy , they spare proteins for building and repair of body
tissues .
4.providing fibers:
Fibers have many beneficial functions, they absorbe water and thus increase the bulk of the
stool so reduce the tendency to constipation by stimulation intestinal movement, also they
making the stool soft (as they resist digestion , bacteria in large intestine emulsify fibers and
make stool soft).
They give protection against CA colon & stomach.
They are reported to reduce glucose level in diabetic patients.
They associated with reduced coronary heart disease ( it binds to bile salts and prevents its
absorption and thus reduce cholesterol level) .
Lipid
A family of compounds that regarded a concentrated source of energy ( 9 kcal/gm), it is nearly
double the energy provided by CHO &proteins.
Fats: are lipid that are solid at room temp.(25C or 77 F)
Oil : are lipid that are liquid at room temp.(25C or 77 F)
Lipid classified in to:
1.simple lipid : triglycerides
The predominant lipids both in food and body are triglycerides (glycerol + 3 f.a ). It can be
synthesis by human body .
2.compound lipid : phospholipids, lipoproteins phospholipids e.g lecithin
Phospholipids are important constituent of cell membrane , they are soluble both in water & fat
so they enable fat soluble substance include vitamins and hormones to pass easily in & out of
cells , also they act as emulsifiers in the body , helping to keep fats suspended in blood and
body fluid ( the food industry uses phospholipids as emulsifier to mix fat and water).
Lipoproteins can be classified as:
Chylomicrons : largest lipoprotein transport
3.derived lipid (sterol) : cholesterol. Present mainly in animal food , many vitally important
body compound are sterol , among them are bile acid , sex hormone (testosterone) , adrenal
hormones , vitamin D3 , as well as cholesterol it self.
Cholesterol synthesis in liver ,cholesterol harmful effect in the body occur when it forms
deposit in the arterial walls , these deposits lead to atherosclerosis , a disease that causes heart
attacks & storks.
Essential fatty acids(EFA) are those that cannot be synthesized by humans. They can be derived
only from food. The important EFA is linoleic acid , also arachidonic acid & linolenic acid.
Source : a.fatty meats, milk, cream, cheeses, egg yolk ,fish .animal fats are mostly saturated.
b. plant source: cooking oils (vegetable) , others include nuts, chocolate , and olives.
Function:
1.source of energy.
2.provide essential f.a.
3.cholesterol help in synthesis of steroid & bile acid.
4.carrier for fat soluble vitamins .
5.provide protection & support to internal organ & bone.
6.fat under the skin provide insulation against cold.
Daily requirement:
20-30% of total energy to be provided by fat , at least 50% of fat intake should consist of
vegetable oil rich EFA.
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Vitamins
Are class of organic compounds categorized as essential nutrients. They required by the body in
very small amounts.they do not provide energy but enable the body to use other nutrients.
Vitamins are divided into 2 groups:
1. Fat soluble vitamins : A,D,E,K.
2. Water soluble vitamins : B vitamins & vitamin C.
Fat soluble vitamins :
A,D,E,K.
These vitamins are insoluble in the watery GI juice , they require bile for their absorption , they
participate in different body activity but the excess amount are stored in liver & adipose tissue
and the storage amount re use if needed , thus people can eat these vitamins less than their daily
need for days, weeks, or months or years and also because of this fact ( Fat soluble vitamins
not excreted but stored ) , the risk of toxicity is greater than water soluble vitamins.
Vitamins A :
It is the first fat soluble vitamin to be recognized ; there are 3 different active form in the body :
retinol , retinal , & retinoic acid , and they are collectively called retinoids.
Animal foods provide retinylesters, a compounds that are readily digested &absorbed as retinol
in intestine.
Plant foods provide carotenoids (pigments) & the most important carotenoid is beta carotene
which can split to form retinol in intestine &liver .
The cell can convert retinol & retinal to the other active forms of vitamin A as needed .
Roles of Vitamins A ( functions):
1.promoting vision : it help to maintain crystal –clear out window
( cornea). Also it contribute to production of retinal pigments (rhodopsin); it is alight sensitive
pigment of the retina which is important in vision in dim light also it help to convert light
energy in to N impulses
(it mainly the role of retinal ).
2.paticipating in protein synthesis and cell differentiation (so it help to maintain the health of
epithelial tissue & skin), Vitamins A role in cell differentiation explain who vit.A may prevent
cancer.
(it mainly the role of retinoic acid ).
3.support growth , reproduction & bone development so when give vit.A supplement to
children , they gain weight & grow taller.
(it mainly the role of retinol ).
Vitamin A deficiency
If a person stop to eat vitamin A containing food, deficiency symptom would not appear until
after store are depleted ( this take 1-2 years in healthy adult but much sooner in growing child).
1. infection: susceptibility to infection is increased in vitamin A deficiency .
Measles is devastating disease , the severity o f illness often correlates with the degree of
vitamin A def. , death are usually due to related infection such as diarrhea & pneumonia , so
WHO recommended routine vit. A supplementation for all children with measles in area where
vit. A def. is a probable or where the measles death are high .
Vit.A supplement also protect against the complication of other life threatening infection
including malaria , lung disease & HIV infection.
2. ocular disease :
Night blindness : the retina does not receive enough retinal to regenerate the visual pigments
bleached by light .
Blindness: vit.A def. is the major cause of childhood blindness in the world, it caused by the
lack of vit. A in the cornea , blindness due to vit.A def. called Xerophthalmia , develop in
stages , at first , the cornea becomes dry & hard (Xerosis) , then the corneal xerosis can quickly
progress to keratomalacia , the softening of cornea that lead to irreversible blindness.
3.Keratinization of body outer surface , the epithelial cell change shape & begin to secret the
protein keratin (the hard inflexible protein of hair & nail ) So the skin becomes dry , rough &
scaly.
Rx : administration of massive dose(110 mg of retinol palmitate orally on 2 successive days).
All children with corneal ulcer should receive vit.A whether or not a deficiency is suspected .
The strategy which has been adopted by many countries against nutritional blindness , is to give
a single dose of 200, 000 IU of vit.A in oil ( retinol palmitate) orally every 6 m to pre school
children (1y-6y) and half the dose to children between (6m-1y).
Prevention :
1.improvement of people diet to ensure adequate intake of vit.A containing food.
2.treatment of contributing factor like respiratory tract infection , diarrhea & measles.
Vitamin A toxicity : hypervitaminosis A , mostly associated with supplement abuse.
Acute toxicity symptom , blurred vision , nausea , vomiting , vertigo, headache & muscle in
coordination.
Chronic toxicity symptom , reduced bone density , bone pain , hepatomegaly, teratogenic
effects.
Vitamin D
There are 2 form of vit.D
1.cholecalciferol vit.D3 is synthesized through the action of UV light on 7- dehydrocholesterol
(provit.D3) in the skin which is converted to previtamin D3 which is in active form which in
turn undergoes hydroxylation in liver to 25-hydroxyvit D3 on further hydroxylation in kidneys ,
the active vit.D is formed (1,25 dihydroxyvit.D3) .D3 stored mainly in liver & fatty tissue.
Because it synthesized inside the body , it regarded as a hormone(not nutrient)
2.ergocalciferol, is produced commercially by UV irradiation of ergosterol (plant steroid) in
mold & yeast. It doesn't occur naturally .
The predominant precursor of vit.D is the first one .
Source:
1.formed in skin by sun exposure.
2.from diet : fish , liver oils , fatty fish , egg &liver , also it can be obtained from fortified milk,
margarine & butter.
Function :
1.mineralization of bones & teeth (rises blood calcium and phosphorus by increasing absorption
from digestive tract) .
2.new studies suggest that it may protect against T.B, gum inflammation , & some cancer.
Daily requirement:
Full term baby 300-400 IU / day.
Premature baby 600-800 IU / day.
Pregnancy & lactation 800 IU / day.
Children & adult 400 IU / day.
Vitamin D deficiency :
In growing child , vit.D deficiency cause rickets which is usually observed in children at the
age 6m-2y . the disease characterized by growth failure , bone deformity , muscular hypotonia ,
tetany and convulsions due to hypocalcemia.
The bony deformities include curved legs, deformed pelvis, pigeon chest , Harrison's sulcus ,
rickety rosary & kyphoscoliosis.
The milestones of development such as walking & teething are
delayed.
2.osteomalacia: in adult, vit.D deficiency cause osteomalacia ( poor mineralization of bone)
characterized by softening of bones , symptom include bending of the spine and bowing of legs.
The disease more common in old females.
prevention :
1.educate the family to expose their children to sunlight.
2.giving periodic prophylactic doses of vit.D for young children (especially those who not
expose to sun light , cloudy or smoggy area).
3.drinking fortified food with vit.D especially milk .
vit.D Toxicity :
it called hypervitaminosis D , characterized by elevated blood calcium & calcification of soft
tissue e.g. blood vessels , lung, kidneys , tissues around joints.
Vitamin E
Other name alpha Tocopherol ( important antioxidant factor)
Source: polyunsaturated plant oils(margarines, salad dressings), green leafy vegetables, wheat,
whole grains, liver , eggyoulks, seeds, nuts, fatty meats.
It is easily destroyed by heat & oxygen
Requirement : 15 mg / day.
Function :
1.it act as antioxidant (defending lipid & other cell components against oxidative factors
damage so it share in stabilization of cell membrane ) ,
2.prevent RBC destruction (haemolysis).
3.involved in immune response & inflammation .
Deficiency
Dietary Deficiency is rare but it usually occur in those with malabsorption diseases, also occur
in those infant who born earlier ( premature) before transfer of vit .E from mother to the baby in
last weeks of pregnancy.
Deficiency cause mild haemolytic anemia.
Treatment : Vit.E supplements.
Toxicity : Vit.E is relatively non toxic.
Vitamin K
Vit.K occurs in at least 2 major forms – vitamin k1 and vitamin k2 .
Vitamin k1 found mainly in fresh gereen vegetable particularly dark green.
Vitamin k2 is synthesized by the intestinal bacteria . which usually provide adequate supply in
man.
Requirement :
Adult : 90-100 microgram/day , infant 2-2.5microgram /day.
Function :
1.Essential for blood prothrombin synthesis which is prompt blood clotting .
2.act as antidote for anticoagulant ( warfarin)
Deficiency :
Occur in long administration of antibiotics which inhibit normal intestinal flora that make vit.k.
Also deficiency occur in newborn infant because their intestine nearly sterile( some time giving
immediately after birth to prevent intracranial bleeding especially in premature baby ).
Deficiency symptoms include: Increase clotting time & bleeding tendency.
Toxicity : not known .
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Water soluble vitamins
B vitamins:
1. Thiamin (B1):
It is part of co-enzyme TPP (thiamin pyrophosphate) which is help in carbohydrate metabolism
, so thiamin play important role in energy production .
Source: the major source , whole grain , fortified or enriched grain , cereals ( rice)& nuts.
While meat, fish , eggs , vegetables & fruits contain smaller amounts.
Milk is important source of B1 in infants .
It is easily destroyed by heat. & it leaks to the water when boiled or blanched.
Requirements :
1.2 mg / day in male
1.1 mg / day in female
Deficiency:
1.beriberi disease (I can't I can't ): occur in 3 types
a.dry beriberi: characterized by peripheral neuritis & muscle wasting it is called neurological
beriberi.
b.wet beriberi: characterized by generalized oedema due cardiac failure (cardiac beriberi).
c. infantile beriberi: affect baby who breast fed by a thiamin deficient mother.it is usually fatal.
2.wernick's encephalopathy : ( seen often in alcoholics) is characterized by ophthalmoplegia ,
polyneuritis , ataxia , and mental deterioration , it occur in sever nutritional depletion.
Prevention:
Beriberi can be prevented by educating people to eat well balanced , mixed diets containing
thiamine rich foods.
Toxicity : not reported
Riboflavin (B2)
Is a member of vit. B group . it has a fundamental role in cellular oxidation . it is play role in
maintaining the integrity of mucocutaneous structure , also it is a part of a co- enzyme FAD
(flavin adenine dinucleotide) that involve in energy metabolism.
Source:
Milk products (yogurt,cheese), whole-grain, fortified, or enriched grain products, liver.
It is easily destroid by UV and irradiation.
Requirement : like vitamin B1
Deficiency : (a riboflavinosis )
Characterized by: sore throat , cracks and redness of corners of mouth(angular stomatitis),
painful , smooth ,purplish red tongue (glossitis), skin lesion covered with greasy
scale(dermatitis).
Toxicity : not reported.
Niacin (B3)
The name niacin describe two chemical structures: nicotinic acid & nicotinamide , nicotinic
acid easily convert to nicotinamide which is the major form of niacin in blood.
The body can make it from the a.a tryptophan .
Function :
1. it essential for CHO , fat & protein metabolism to produce energy.
2. play a role in normal skin , intestine, & nervous system.
3. it regarded as cholesterol lowering agent.
Source: milk , eggs , meat , poultry, fish , whole-grain, fortified, or enriched grain products, all
protein containing foods.
Deficiency
Niacin deficiency results in pellagra , the disease characterized by 4D's : diarrhoea , dermatitis ,
dementia and eventually death. In addition to angular stomatitis & glossitis.
Prevention
A good mixed diet containing milk and/or meat is regarded as an essential part of treatment
&prevention.
Toxicity
Usually associated with large dose of niacin supplement,the most common feature of toxicity is
niacin flush which characterized by painful flush , burning , tingling & itching sensation due to
dilatation of capillaries. Also toxicity cause nausea & vomiting .
Those consuming limited diet rich in corn products ( inflammatory bowel disease ) ,
alcoholism, liver disease , diabetes , peptic ulcer.
Pyridoxine (Vitamin B6)
Occur in 3 forms : pyridoxal , pyridoxine , and pyridoxamine .all of them can be converted to
the co-enzyme pyridoxal phosphate (PLP) which is the active form that play important role in
a.a &f.a metabolism.
B6 help to convert tryptophan to niacin and to serotonin (neurotransmitter )also it help to make
RBC.
Source : milk , liver , meat , egg yolk , fish , whole grain cereals , legumes & vegetables. It is
easily destroyed by heat .
Requirement: 1.3 mg/day.
B6 deficiency :
It associated with peripheral neuropathy .
depression , confusion , convulsion ( due to decrease neurotransmitter synthesis ).
Alcohol lead to destruction & loss of vit.B6.
INH(isonicotinic acid hydrazide) act as vit.B6 antagonist so B6 supplement must be given.
B6 toxicity :
Usually occur after taking more than 2g of B6 daily , it occur in form of neurological damage
causing numbness and muscle weakness .
Also toxicity occur in those take B6 supplement for carpel tunnel syndrome & sleep
disorder(seem to be in effective)& because Large dose taken for months to years irreversible
nerve degeneration may occur.
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Folate
Alternative name is folacin & folic acid , it is part of coenzymes THF (tetrahydrofolate) and
DHF(dihydrofolate) that used in DNA synthesis and therefore it is important in new cell
formation . for folate coenzyme to function , it needs to be activated by enzyme that requires
the help of B12.
Total body store are small & deficiency can occur in a matter of weeks.
Function
1.involve in DNA synthesis so it is important in new cell formation especially RBC in bone
marrow.
2.it reduce the risk of neural tube defects(spina bifida,anencephaly) , so it given routinely to
pregnant females in 1st trimester
3.play a role in brake down the homocysteine which seem to enhance the clot formation &
arterial damage so give protection against heart disease.t
4.it may prevent ca.pancreas & ca.breast.
Source : fortified grains, leafy green vegetables , legumes , seeds , liver.
Requirement : 400 microgram / day, the need increase during pregnancy & in growing children
.
Deficiency
It occur in: 1.in infant who were fed goat's milk which is low in folate
2.increase metabolic requirement as in pregnancy , cancer , infection such as chicken pox &
measles , burn …)
3.impaired absorption as in malabsorption syndrome .
4.drug interaction e.g. methotraxate (anticancer), phenytoin , aspirin , antacid.
5.alcohol & smoking.
It results in megaloplastic anemia , glossitis , cheilosis and gastrointestinal disturbance (
diarrhoea & abdominal destention). Severe folate deficiency may cause infertility & sterility .
Treatment: oral folic acid 5 mg /day for 3 weeks.
Toxicity
Excess consumption of folate fortified food or supplements mask vit.B12 deficiency
symptoms.
Vitamin B12(cobalamin)
Is organo-metallic compound with cobalt atom , it is closely related to folate (each depend on
other for activation), it is part of coenzyme methylcobalamin.
Vitamin B12 absorption needs intrinsic factor from the stomach and absorption occur in the
terminal ileum.
Function
1.it cooperates with folate in the synthesis of DNA so use in new cell formation .
2.help to maintain the myelin sheath that surrounds and protect nerves.
3.help to break down some fatty acids to aminoacids .
Requirments 2.4 microgram /day.
Source
Food of animal origin (meat , fish , poultry , milk , cheese , eggs) , fortified cereals.
Deficiency
Occur due to inadequate absorption , and rarely due to inadequate intake.
Vitamin B12 Deficiency is associated with megaloblastic anemia (pernicious anemia) ,
degeneration of peripheral nerves progressing to paralysis , sore tongue , loss of appetite,
constipation.
Toxicity : not reported
Vitamin C (ascorbic acid)
It is water soluble vit. , it is the most sensitive of all vitamin to heat.
Function
1.Vit.c is potent antioxidant
2. it is needed for the formation of collagen which provide support for blood vessels , bone ,
cartilage & connective tissue ( this explain why in vit C def. this supports fails , with the result
of local hemorrhage & bone fractures.
3.it reduce ferric iron to ferrous iron , facilitates the absorption of iron from vegetables.
4.act as natural antihistamine so useful in common cold.
5.assist in some hormone synthesis like thyroxin .
Source
Citrus fruits , dark green vegetable , tomatoes , potatoes , strawberries .
Requirement
Male : 90 mg /day
Female : 75 mg / day
Smoker need more vit . C because smoke contain oxidents
Deficiency
Lead to a disease called scurvy which characterized by swollen and bleeding gums ,
subcutaneous bruising or bleeding into the skin or joints, delayed wound healing , anemia.
Toxicity :
nausea , diarrhoea , headache .
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Water and minerals
Water makes up about 60% of adults body's weight .
Role in the body:
It assists the transport of nutrient and waste products throughout the body
participates in chemical reactions
Act as solvent for mineral , vitamins , amino acids , glucose & many other small molecule
Serves as shock absorber as it found around joints,and inside the eye also in spinal cord and in
pregnant lady in amniotic sac around the baby
Regulates body temperature.
To maintain water balance : intake from liquids , food , and metabolism must equal losses from
kidneys, skin , lungs & GIT .
The amount and type of water a person drinks may have a positive or negative health effects.
Water requirement : men : 3.7 L/day.
Women: 2.7L/day.
Minerals
In organic elements , it is vital for human health as it required for growth, repair and regulation
of vital body function.
It cannot destroyed by heat or air
It may lost from food when they leach into cooking water.
Minerals are divided into 2 group: major minerals and minor minerals.
major minerals:
named major because it found in the human in amount greater than 5 mg . sometimes called
macrominerals
Include: sodium , chloride , potassium , calcium , magnesium & sulfur.
Calcium : is the most abundant mineral in the body . 99% of body's calcium is in the bones
(&teeth) , where it play 2 roles :
1. it is an integral part of bone structure , providing a rigid frame that hold up the body up
right & serve as attachment points for muscles.
2. it serve as calcium bank , offering a readily available source of calcium when a drop in
blood calcium occur.
Ionized calcium in plasma has many other vital functions including coagulation of blood ,
muscle contraction , cardiac action , milk production in female , have a role in enzyme &
hormone metabolism .
It may protect against hypertension, diabetes and colon cancer.
Source:
It is found mainly in milk and milk products , egg , small fish with bones. It present in green
leafy vegetable & cereals but it is poorly absorbed from them because of the presence of oxalic
acid in green leafy vegetable and phytic acid in cereals, which make calcium oxalate & calcium
phytate (insoluble compounds).
Vitamin D, acid in stomach , lactose (in infants) all enhance calcium absorption.
High phosphorous intake , oxalate & phytate in diet , vit. D deficiency & lack of stomach acid
all inhibit calcium absorption.
Requirement :
Increase in pregnancy and growing children.
1000 mg/day (18-50y)
1200 mg/day (over 51 y)
Deficiency : when calcium intake is inadequate , blood calcium remain normal but this on
expense of bone so patient will suffer from stunted growth (in children) and bone loss (
osteoporosis in adult)
Toxicity : constipation , increase risk of urinary stone formation & interfere with absorption of
other minerals.
Phosphorous
It is essential for the formation of bone & teeth(about 85% of it found in combination with
calcium in bones & teeth).
Function
1.has vital role in mineralization of bone & teeth.
2.phosphorous salts present in all body cells as a major part of buffer system .
3.it is apart of DNA &RNA therefore it necessary for all growth process .
4.it assist in energy metabolism , ATP itself uses 3phosphate groups to do it's work.
5.it combined lipid to form phospholipid which is the major structural component of cell
membrane.
Source: all animal tissues (meat , fish , poultry , egg &milk)
Deficiency : dietary deficiency is rare because phosphate are present in all kind of food .
Deficiency Symptoms include : weakness & bone pain .
Toxicity : calcification of non muscular tissue , particularly the kidneys.
Sodium
is the main cation outside cell , it's found in all body fluid, so it's lost from the body thought
urine & sweat.
Source:
Table salt, soy sauce , moderate amount in meat , milk , bread & vegetables . large amount in
processed food.
Function
1. maintain normal fluid & electrolyte balance.
2. assist in nerve impulse transmission .
3. involve in muscle contraction .
deficiency
dietary deficiency is rare but it may occur due to vomiting , diarrhoea , and heavy sweating that
cause muscle cramps , mental apathy & loss of appetite .
toxicity : acute hypertension & oedema.
Chloride
Is the major anion outside cells & it associated closely with sodium.
Source:
Table salt,soy sauce , moderate amount in meat , milk , egg & vegetables . large amount in
processed food.
Requirement
2300 mg/day (19-50 yr)
2000 mg/day (51-70 yr)
1800 mg/day (> 70 yr)
Function
1.maintain normal fluid & electrolyte balance.
2.part of hydrochloric acid in the stomach , necessary for proper digestion .
Deficiency : do not occur under normal circumstances.
Toxicity : vomiting .
Potassium , K
Intracellular cation potassium , like sodium & chloride it is an electrolyte that plays an
important role in maintaining fluid balance.
Function
1.maintain normal fluid & electrolyte balance.
2.facilitate many reactions.
3.assist in nerve impulse transmission & muscle contraction .
Source : meats , milk , fruits , vegetables , grains & legumes.
Deficiency : a companied with dehydration due to diarrhea & vomiting , fluid loss , irregular
heart beat , muscular weakness , glucose intolerance.
Toxicity symptom : result from over consumption of k salts & from certain disease or
treatment , muscle weakness & vomiting.
Magnesium
Like calcium & phosphorus , magnesium supports bone mineralization human body contain 25
gm of magnesium of which half is found in the skeleton .
Function :
1.bone mineralization.
2.necessary for energy metabolism & synthesis of ATP .
3.it involved in muscle contraction and blood clotting , while calcium promote these
processes , Mg inhibit them . this dynamic interaction between the 2 minerals help in
regulate blood pressure & lung function.
4.it support normal function of immune system.
Source : nuts , legumes, whole grains , dark green vegetable , see food , chocolate , cocoa.
Requirement: men (19-30 yr) 400 mg/day
women (19-30 yr) 300 mg/day
Deficiency : rarely occur due to dietary insufficiency , it usually associated with chronic
alcoholics , liver cirrhosis , toxemia of pregnancy , protein malnutrition , kidney disorder &
prolong vomiting & diarrhea .
Symptom : tetany , impair CNS activity and may be responsible for hallucinations during
alcohol withdrawal .
Toxicity : although it is rare , but if occur it is fatal.
Lec:7
Trace minerals
Essential mineral nutrients found in the human in amount smaller than 5 mg . sometimes
called microminerals e.g. Iron , zinc , Iodine , Selenium , Copper , Manganese , Fluoride.
Iron
Iron is of great importance in human nutrition , the adult human body contains between 3-4
g of iron , of which about 60-70 percent is present in the blood (Hb iron) as circulating iron
& the rest as storage iron.
Function
Iron necessary for many function in the body including :
1.formation of Hb , that carry O2 in the body.
2.brain development & function .
3.regulation of body temperature.
4.part of the protein myoglobin in the muscle which makes O2 available for muscle
contraction.
5.serves as cofactor that accelerates the enzyme reaction.
.Requirments :
Men : 8 mg /day.
Women (15-45 yrs): 18 mg /day.
Iron absorption & metabolism
Iron in food ………….. mucosal cells in the intestine store excess iron in mucosal ferritin (a
storage protein) ………if the body need iron ………………. Mucosal ferritin releases iron
to mucosal transferrin (a transport protein ) , which hands off iron to anther transferrin(
blood transferrin) that travels through the blood to the rest of the body.
Blood transferring delivers iron to bone marrow which uses large quantities to make new
RBCs .
If thebody does not need iron ………..iron is not absorbed and is excreted in shed intestinal
cells instead. Thus , iron absorption is reduced when the body does not need iron.
The absorbed iron is transported as plasma ferritin and stored in liver , spleen , bone
marrow and kidney .
When the concentration of iron becomes abnormally high , the liver converts some ferritin to
anther storage protein , hemosiderin .
Source
They are 2 form of iron
Haem iron and nonhaem iron.
Haem iron : liver , meat , poultry and fish.
nonhaem iron : cereals , green , leafy vegetable , legumes , nuts , dried
fruits.
Haem iron is better absorbed than non-haem iron
Factors that enhance non-haem absorption
1.MFP(peptide released during the digestion of Meat , Fish , and Poultry) . it enhance the
non haem iron absorption when eaten at the same meal.
2.vit . C enhance the absorption by capturing the iron and converting the insoluble ferric iron
in foods to more soluble ferrous iron.
3.gastric acidity & some sugars.
Factors that inhibit non-haem absorption:
1. Phytates in legumes , grains and rice
2.Vegetable proteins in soybeans , legumes , nuts.
3.Calcium in milk .
4.Tannic acid in tea & coffee.
Iron deficiency
It is the most common nutrient deficiency that lead to iron deficiency anemia IDA
Three stages of iron deficiency have been describe
A. first stage , characterized by decreased storage of iron without any other detectable
abnormalities.
B. Characterized by a decrease in transport iron (s.iron falls)& and the iron carrying protein
transferrin increases (as adaptation measure) so the more transferrin and the less s.iron
will reflect the severity of deficiency .
C. Occur when the lack of iron limits Hb production . Hb and hematocrit values decline. It
is late indication for iron deficiency which may represented as iron deficiency anemia .
Treatment
People who are iron deficient may need supplements (ferrous sulphate) as well as iron rich
food and absorption-enhancing diet and avoid absorption-inhibiting diet.
Toxicity
The excess iron may cause hemosidrosis , a condition characterized by deposition of
haemosidren ( iron storage protein ) in liver , heart , joints , and skin causing their damage .
infection is common because bacteria grow on iron rich blood. So patient complain from
infection , fatigue , joint pain , skin pigmentation , organ damage.
Iron poisoning
Ingestion of large doses of iron containing supplements cause nausea , vomiting , diarrhea ,
palpitation , encephalopathy and liver failure .
Death in young children due to heart failure.
Zinc
Is present in all cells but the high concentration are found in muscle and bone. It is act as a
cofactor for more than 100 enzymes.
Function
1.zinc supports the work of numerous proteins in the body , such as the metalloenzymes
which involve in a variety of metabolic process including regulation of gene expression.
2.zinc stabilizes cell membranes .
3.it assists in immune function and in growth and development.
4.zinc participates in the synthesis , storage and release of insulin from pancreas.
5. it interacts with platelets in blood clotting .
6.affects thyroid hormone function
7.it is needed to produce active form of vit.A in visual pigments , and the retinol binding
protein that transports vit.A.
8.it is essential to normal taste perception , wound healing , the making of the sperm and
fetal development.
Source
Protein –containing food: red meats, shellfish , whole grains, some fortified cereals.
Deficiency
Is common in children from developing countries due to lack of intake of animal food, high
dietary phytate content, inadequate food intake and increased faecal losses during diarhoea.
Symptoms :Growth retardation , delayed sexual maturation , impaired immune function ,
hair loss , eye and skin lesion & loss of appetite.
Treatment : diet rich in zinc , zinc supplementation.
Zinc supplementation in combination with oral rehydration therapy has been shown to
significantly reduce the duration and severity of acute and persistent diarrhea.
Toxicity :
Dose over 50 mg cause vomiting , diarrhea , headache , copper & iron deficiency.