Physiology of Starvation

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DR. PARAS PAREKH

1ST YEAR RESIDENT

DEPARTMENT OF PHYSIOLOGY

B.J. MEDICAL COLLEGE



Starvation is the result of asevere or total lack of

nutrients needed for themaintenance of life.



Severe reductionin vitamin, nutrient and energyintake.

Most extreme formof malnutrition. In humans, prolonged starvation can

cause permanent organ damage andeventually, death.



Fasting is refraining fromeating and drinking, for certain

period of time. Can be done for a day toseveral weeks.



Used for thousands of years, fasting is one of

the oldest therapies in medicine

Many of the great doctors of ancient times

and many of the oldest healing systems have

recommended fasting as an integral method

of healing and prevention



Fasting has also been used in nearly every religion

in the world, including Hinduism, Christianity,

Buddhism, and Islam. Many of history's great

spiritual leaders fasted for mental and spiritual

clarity, including Jesus, Buddha, and Mohammed.

In one of the famous political acts of the last

century, the Indian leader Mahatma Gandhifasted for 21 days to promote peace



In ancient times, Starvation wasused as a DEATH SENTENCE.



On the basis of intake of food…

1) Dry fasting. Absolute Fast, Black Fast, and HebrewFast.Most extreme

Has spiritual rootsConsists of foregoing food and waterfor short periods.



2) Liquid fasting.

Fasting on liquids only.

Water fasting Simplest and perhaps the oldest form.Delivers the greatest level of

therapeutic benefit physically and in ashort period of time. Juice fasting

Extremely popular.Nutritional support in a pure andnatural form.

http://www.allaboutfasting.com/water-fasting.html

http://www.allaboutfasting.com/juice-fasting.html

http://www.allaboutfasting.com/juice-fasting.html

http://www.allaboutfasting.com/water-fasting.html



Foods

Protein Polysaccharides Lipids

Aminoacids Mono & Fatty acidsDisaccharides Glycerol

Glycolysis

Pyruvate



Acetyl CoA

NADHElectron transport

& Oxidative

O2 Phosphorylation

NH3 H2O ATP + NAD CO2

Citricacidcycle



During metabolism, first there is a hydrolysisof macromolecules to their subunits.

Conversion of subunits to acetyl CoA andproduction of a small amount of ATP andNADH.

Oxidation of acetyl CoA to water and carbondioxide

Considerable amount of ATP is produced.



Liver glycogen is first mobilised,

Gluconeogenesis from glucogenic amino acids

and later on from other substrates also.

Last for not more than 2 to 3 days.



Major part of energy is derived from Fats ofadipose tissue and remaining from Proteins.

Last longer,usually over two weeks becauseadipose tissue represents the largest amountof stored food.



Fat stores are almost exhausted so energy isobtained from the breakdown of tissue protein.

Cell substance will break up and cell metabolismis disrupted.

This stage last for less than one week and if

continued leads to death.



Time after eating

S o u r c e o f g l u c

o s e / e n e r g y

glycogen

gluconeogenesis, muscle

gluconeogenesis, other

fatty acid oxidation

food



Time after eating


o s e / e n e r g y

glycogen




food



Intestine

Muscle

Liver

Brain

Kidney

Gluconeogenesis

Ketogenesis

Ureagenesis

Glutamine

Alanine / PyruvateGlucos

e

Ketones

Urea

NH3

Ketones

Glycerol

AGLFat



Intestine

Muscle

Liver

Brain

Kidney

Gluconeogenesis

Ketogenesis

Ureagenesis

Glutamine

Alanine / PyruvateGlucos

e

Ketones

Urea

NH3

Ketones

Glycerol

AGL

Fat



CARBOHYDRATE

FATS

PROTEIN

WATER

EFFECTS OF STARVATIONON

BASIC NUTRIENT'S

METABOLISM



Hypoglycaemia

Depresses Insulin Increase Glucagonsecretion activity

Increases Gluconeogenesis Increase Glycogenolysis

Insulin/glucagon ratio decrease.



Increase in activity of glucogenicenzymes like pyruvate carboxylase,

FDPase, glucose 6-P-ase that increaseboth gluconeogenesis and glycogenolysis.

Starvation decrease activity of enzymeG-6-PD, thus reducing HMP shunt andlipogenesis from carbohydrate.



All this factors try tomaintain Blood sugar level asBrain and Red blood cellsrequire continuous supply of

Glucose in all condition.



10

20

30

40

I II III IV V

Exogenous

Glycogen

Gluconeogenesis

G L U C O S E U T I L I Z

E D

( g / h o r a )

Ruderman NB. Annu Rev Med 1975;26:248

I II III IV V

GLUCOSEGLUCOSE GLUCOSEGLUCOSE,

KETONES

GLUCOSE,

KETONES

FUEL FOR

BRAIN

LEGEND



Carbohydrate reserves are insufficient.

Fats of adipose tissue is largely

mobilised to the liver as FFA andoxidised for energy purposes.



Starvation increase the activities ofthe ‘Hormone sensitive lipase’, so there

is increase in lipolysis in the adiposetissue.

Lipolysis release two components:Glycerol and FFA.

Glycerol acts as a substrate forGluconeogenesis and joins thecarbohydrate pool.



FFA rise in the plasma from the veryfirst day of starvation and this rise isenhanced by muscular work, probablybecause of increased secretion ofcatecholamines from adrenal medulla

and sympathetic nerve ending.

As FFA level increase, ketogenesis is

stimulated and ketone bodies areformed.



Vital organs like Brain and Heart canutilize ketone bodies during prolongedstarvation for survival.



When fat stores are depleted andexhausted, proteins alone are availablefor energy purpose.

Tissue proteins are treated as ‘foodproteins’ , they are hydrolyzed to aminoacids to a larger extent.



Released amino acids are utilized for themaintenance of the structural and functionalefficiency of vital organs.

Amino acids undergo de-amination in the liverand the non-nitrogenous part helps in the

maintenance of blood sugar level bygluconeogenesis.

Nitrogen excretion in urine is an index of tissue

protein consumption.



During first few days, ECF is reduced due tostoppage of water intake and continuedobligatory losses.

On prolonged starvation,the ICF volume alsofall because of cellular breakdown while ECFshows a relative expansion due to the

subsequent shrinkage of cell mass that mayproduce oedema.



Cellular disintegration cause loss ofintracellular potassium thus reducing

total body potassium.

The need for drinking water is reduced

after few days due to relativeexpansion of ECF.



Mostly observed in animals, but some directobservation have been carried out onvolunteers and on professional fasting person.

During the first few days,craving for foods, at meal times.Later on this craving subsides

Desire for food vanishes.



Weakness gradually increases. Strong dislike to undertake any physical

or mental effort. Subject falls into a state of

semiconsciousness.

Sleep increases and respirationbecomes slower. Body weight is steadily lost. The daily

loss in man during the first 10 days, isbetween 1 to 1.5% of the original bodyweight.



Adipose tissue get thinned out andfinally disapper, visceral organs get

displaced.

Due to loss of subcutaneous fats skin

hangs loose with folds.

Vital organs lose the least weightwherease the less vital ones lose themost.



http://www.fasting.ws/juice-fasting/pic/diet-maintenance.jpg



Breaking the fast is harder thanfasting.

The longer the fast the more difficultit is to break correctly.

Start with fruits and raw vegetables insmall quantities and after three to fourdays gradually start your regular diet.

Avoid junk food for few days.



When breaking from water fasting, go

to a juice fast for two days or eatfruits like oranges, mangos or pears.

In severe condition glucose is startedintravenously.



Rest the digestive system Weight loss Allow for cleansing anddetoxification of the body

Promote greater mental clarity



lead to a feeling of physicallightness, increasing energy level

From past to at present fasting hasbeen a catalyst to a number ofrevolution.



Headache

Nausea

Muscle aches

Muscle cramps due to mineraldeficits such as sodium, potassium,calcium,magnesium, and phosphorus.

l d ld d l d



Blood pressure could drop, leading tofainting spells especially when you tryto sit up or stand after lying down.

Uric acid levels may rise, causing severeattacks of gout or a uric acid kidney

stone.

Ventricular arrhythmias, experienced

usually during long water fasts.



Deprivation of water along with foodfollows death in approximately 7 to 10

days time whereas food starvation in 3to 4 weeks or even longer depending onthe reserve of fats in the body.

Longest period of survival neverexceeds 9 to 10 weeks.



CLINICAL

ASPECTS-

PROTEIN ENERGYMALNUTRITION



The term protein energy malnutrition hasbeen adopted by WHO in 1976.

Highly prevalent in developing countriesamong <5 children; severe forms 1-10% &underweight 20-40%.

All children with PEM have micronutrientdeficiency.

It is most prevalent in South Asia and subsaharan africa.



There are two varities of PEM1) Marasmus2) Kwashiorkor.



The term derived from the Greek marasmos, which means wasting.

Inadequate intake of protein and calories and

is characterized by emaciation.

Represents the end result of starvationwhere both proteins and calories aredeficient.



Severe wasting of muscle & s/c fats Severe growth retardation Child looks older than his age

Alert but miserable Hungry Diarrhoea & Dehydration



Lack of physiological adaptation tounbalanced deficiency.

Body utilized proteins and conserve S/C fat.

Marasmus represents an adaptive responseto starvation, whereas kwashiorkorrepresents a maladaptive response tostarvation.



Oedema

Psychomotor changes

Growth retardation

Muscle wasting



Moon face

Hair changes

Skin depigmentation

Anaemia



Hypoglycemia Hypothermia Hypokalemia

Hyponatremia Heart failure Dehydration & shock Infections (bacterial, viral & thrush)



Guyton and Hall

Indian journal of Physiology.

Harpers textbook of Biochemistry.

Chatterjee-textbook of Biochemistry.

Journal of Biochemistry.

Physiology of Starvation

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