NUTRIENT INTERACTION Nutrient - PowerPoint Presentation

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NUTRIENT INTERACTION

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Nutrient

A chemical compound (such as protein, fat, carbohydrate, vitamins, or minerals) that make up foods. These compounds are used by the body to function and grow.

Nutrient can be classified as

Macronutrients

There are three macronutrients defined as being the classes of chemical compounds humans consume in the largest quantities and which provide bulk energy .These are organic nutrients like PROTEIN, FAT and CARBOHYDRATES.

Micronutrients

These are inorganic nutrients such as minerals and vitamins which are required by body in very small quantities.

Nutrient Interaction

It can be defined as the physical chemical interaction between nutrients, or between nutrients and other components of the diet or other compounds, including desirable or undesirable results.

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Carbohydrate –carbohydrate interaction

Carbohydrates are important nutrient which provide energy to our body .It is an organic compound made up by carbon ,hydrogen and oxygen.

Inter- relation between Fructose and Sucrose

When fructose is ingested as a part of the dissaccharide sucrose ,absorption capacity is much higher because fructose exists in a 1 : 1 ratio with glucose.

In addition ,serum galactose levels following galactose ingestion are reduced when accompanied by glucose.

Inter –relation between Carbohydrate – Fiber

FIBER is a type of polysaccharides which found in plants and it gives structure to plants.

There is a 2 type of fibers like soluble and insoluble fiber.

Soluble fiber such as pectin etc mixes with water to form gummy substances that coats the insides of the intestinal tract

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During digestion, wave-like currents caused by contractions of the intestinal muscles bring nutrients to the surface of the intestinal wall for absorption. After soluble fiber dissolves in water, however, it traps nutrients inside its gummy gel and slows down considerably while moving through the digestive tract. Inside the gel, nutrients are shielded from digestive enzymes and less likely to reach the wall of the intestines.

Dietary sugars like carbohydrates and starch are among the nutrients trapped inside this gel. Consequently, sugar is absorbed into the bloodstream more slowly, blunting the sharp spike in blood glucose typically experienced by diabetic patients after a meal. Fewer spikes in blood glucose lead to greater sensitivity to the action of insulin. Avoiding high peaks and low valleys in blood glucose places less stress on the pancreas and is important not only to diabetics but also to those who want to prevent the development of type 2 diabetes

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Glycemic Index

The

glycemic index

is a measure of the effects of carbohydrates in food on blood sugar levels. It estimates how much each gram of available carbohydrate (total carbohydrate minus fiber) in a food raises a person's blood glucose level following consumption of the food, relative to consumption of glucose.

Plasma glucose level rise 5-45 min after any meal that contains sugars or digestible starch and return to fasting levels 2-hours

later.White

bread has a

glycemic

index of 100 and other foods have a lower

glycemic

index.

Foods with a high

glycemic

index, such as processed starches and the sugar in soft drinks, break down into glucose and enter the bloodstream relatively quickly.

Unrefined, complex carbohydrates, on the other hand, have a low

glycemic

index and digest more slowly. Diabetic patients should consume food with a low

glycemic

index because rapid increases in blood glucose exacerbate overproduction of insulin by the pancreas and insulin resistance.

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The

glycemic

index depends on:

1.Composition and size of starch particles

Smaller the particle size more is the

glycemic

effect .Raw foods with large particles therefore have a lower effect on

glycemic

index.

2.Their digestibility

Presence of

amylopectin

that gets rapidly digested also has a greater

glycemic

effect whereas the amount of

amylose

which is digested slowly has low

gycemic

index.

3.Cooking methods employed

Foods cooked by boiling and long cooking process makes it easy to digest and reduces the particle size thus increasing the

glycemic

index.

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Carbohydrate –Protein Inter-relations

1.

Carbohydrate and Hormones

Glucagon

, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels.

The pancreas releases glucagon when

blood sugar

(glucose) levels fall too low. Glucagon causes the

liver

to convert stored

glycogen

into

glucose

, which is released into the bloodstream and also from non CHO substances like amino acids etc.

High blood glucose levels stimulate the release of insulin. Insulin allows glucose to be taken up and used by insulin-dependent tissues.

Thus, glucagon and insulin are part of a feedback system that keeps blood glucose levels at a stable level.

So, Glucagon is responsible for

gluconeogenesis

and

glycogenolysis

.

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Cortisol

It is a hormone produced by adrenal gland .

Its function is to increase blood sugar through

gluconeogenesis

; suppress the immune system; and aid in fat, protein and carbohydrate metabolism so , it is an overall catabolic hormone ,which decreases lean body mass and muscle mass and may increase energy expenditure.

Cortisol

withdrawal increase insulin sensitivity

interms

of increased glucose oxidation and decrease glucose production . This may include hypoglycemia in

adrenocortical

failure.

2.Protein sparing action

During fasting or starvation or insufficient carbohydrates and fats for fuel ,body stores of glycogen are

exhausted.Body

adapts to use of muscle protein to meet most of the need of glucose production ,mainly needed for brain , RBCs etc, and this is done by

gluconeogenesis

.

But to use protein instead of carbohydrates to give energy is not a wise contribution as the urinary nitrogen excretion increases during starvation.

If

carbohydreates

are sufficient, then protein can be spared of tissue building process

.

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3.Glucose and

Alanine

Alanine

plays a key role in glucose–

alanine

cycle between tissues and liver. In muscle and other tissues that degrade amino acids for fuel, amino groups are collected in the form of

glutamate

by

transamination

. Glutamate can then transfer its amino group through the action of

alanine

aminotransferase

to

pyruvate

forming

alanine

and α-

ketoglutarate

. The

alanine

formed is passed into the blood and transported to the liver.

A reverse of the

alanine

aminotransferase

reaction takes place in liver.

Pyruvate

regenerated forms glucose through

gluconeogenesis

, which returns to muscle through the circulation system. Glutamate in the liver enters

mitochondria

and degrades into

ammonium ion

through the action of

glutamate

dehydrogenase

, which in turn participate in the

urea cycle

to form

urea

.

The glucose–

alanine

cycle enables

pyruvate

and glutamate to be removed from the muscle and find their way to the liver. Glucose is regenerated from

pyruvate

and then returned to muscle: the energetic burden of

gluconeogenesis

is thus imposed on the liver instead of the muscle. All available

ATP

in muscle is devoted to muscle contraction

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4.Fiber and

Trypsin

Fiber i.e. cellulose has also been shown to reduce the

actvitiy

of human pancreatic

trypsin

in protein

digestion.This

is shown as slightly increased

faecal

loses of nitrogen on increased fiber diet . In addition amylase and lipase activity is also depressed.

5.

Maillard

reaction

When a reducing sugar is heated with protein , a

maillard

reaction occurs that reduces the availability of some amino acids , like lysine. The monosaccharide in intestinal lumen may influence rate of uptake of certain amino acids ,fructose seeming to accelerate this reaction e.g.

During milk processing or heat treatment ,milk sugar lactose react with free side chains of lysine residues to render it unavailable .

Under sever heating

conditions,in

presence of sugar ,food protein becomes resistant to digestion so that availability of amino acid is reduced.

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6.Enzymes and carbohydrate hydrolysis

When enzymes concerned with hydrolysis of carbohydrate are missing or inadequate, common symptom is osmotic diarrhea .This condition may arise because of congenital absence of appropriate enzyme required for digestion of lactose ,sucrose or maltose.

Inadequancies

of these enzyme may also be secondary to gut mucosal damage due to such condition as celiac

disoder

or protein deficiency.

7. Glucose and tryptophan

Amino acid uptake across the blood brain

barrrier

is influenced indirectly by serum glucose in that the insulin concentration is directly related to movement of tryptophan into brain.

The disorders fructose

malabsorption

and lactose intolerance cause improper absorption of tryptophan in the intestine, reduced levels of tryptophan in the blood

and depression.

8.Glucosamine and Collagen

Glucosamine (an amino monosaccharide found in chitin ,

glycoproteins

and

glycosaminoglycans

such as

hyaluronic

acid and heparin sulfate) provides the primary substrate for both collagen and

proteoglycan

synthesis.

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9.Genetic errors

Genetic errors may also occur in conversion of fructose and

galactose

.Absence of enzyme

fructokinase

in liver prevents fructose breakdown and is excreted in urine i.e.

fructosuria

.

Diminished activity of fructose -1-phosphate

aldose

in liver results in hypoglycemia and

hypophosphatemia

with associated vomiting.

Clinical forms of

glactosemia

occur as inborn errors of metabolism and result of enzyme

deficincies

.Deficient enzyme is galactokinase in which galactose is not phosphorylated.This may lead to cataract in otherwise normal subject .Also glucose-6-phosphate dehdrogenase deficiency result in inability to maintain glutathione in reduced form during exposure to drugs such as sulfonamides or some antimalarials ,leading to haemolysis or anemia.

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Carbohydrate – Fat Inter-relation

1.Conversion into fat

Glucose is a six-carbon sugar molecule and body first converts this molecule into two three-carbon

pyruvate

molecules through the process of

glycolysis

and then into acetyl

CoA

. When body requires immediate energy, acetyl

CoA

enters the Citric Acid Cycle creating energy molecules in the form of ATP. But when glucose intake exceeds then acetyl

CoA

begins the process of fatty acid synthesis becoming triglycerides that are stored in the fat tissues of body. These triglycerides are stored energy molecules which can be broken down later to give energy when need , for example, get up off the couch and go for a bike ride.

Regulation of Fatty Acid Synthesis

Fatty acid synthesis is influenced by foods which we eat and hormones we release. When blood glucose levels are high, such as after eating a sugary meal, body releases insulin. Insulin stimulates the formation of Fatty Acid

Synthase

, an enzyme that increases fat storage.

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On the other hand, polyunsaturated fatty acids decrease the formation of the Fatty Acid

Synthase

enzyme, implying that eating foods containing polyunsaturated fats may not lead to as much increased fat storage as eating sugary foods. In addition, when fat cells increase their fat storage, a molecule called

leptin

is produced.

Leptin

leads to decreased food intake, increased energy expenditure, as well as inhibition of fatty acid synthesis.

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2.Prevent ketosis

The primary function of CHO is to provide energy .However during low CHO intake ,fats are mobilized to meet the energy requirement of body . This result in increased plasma free fatty acids and

ketone

bodies .Hence, sufficient amount of CHO spares fats from being broken down

.

3.Chitin and Cholesterol

Chitin (a polysaccharide found in the exoskeleton of some invertebrates e.g. Insects ,crustaceans0 and

chitosan

, have

hypocholestrolemic

effect . The strong positive charge on

chitosan

binds negatively charged lipids blocking their absorption

.

4.Fiber and Lipid

Serum lipid concentration can be modified by insoluble fibers such as cellulose ,

lignin,chitin

and more soluble fibers because

Fibers bind

faecal

bile acid and increases excretion of bile acid-derived cholesterol.

Fiber prevents dietary fat and cholesterol absorption by binding bile acids or fats and lipids.

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Fermentable oligosaccharides and dietary fiber are converted by intestinal bacteria to short chain fatty acids, which lower blood lipids by mechanisms that are currently unclear.

So Fiber decreases the absorption of dietary cholesterol from the intestine.

Further ,fiber binds with bile salts and reduces their

enterohepatic

circulation.This

cause increased degradation of cholesterol to bile salts and its disposal from the body.

Carbohydrate-Mineral inter-relations

Carbohydrate and Zinc

Highe

fiber diet is associated with zinc deficiency .Zinc absorption may be enhanced by glucose and lactose intake

.

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Carbohydrate and Calcium

It is seen that lactose improves the absorption of calcium from the gut . Even in adults with lactose intolerance ,lactose probably improves Ca absorption. Sugars and organic acids produced by microbial fermentation of sugars in the gut increases the solubility of calcium salts and increases their absorption .

Fiber may decrease calcium absorption ,this process occurs if calcium intake is more than 30gm per day.

3. Carbohydrate and Iron

Wheat bran includes low serum iron levels as they contains

phytate

which inhibits iron absorption . In this regard iron absorption from unpolished rice is significantly worse then from polished rice.

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4.Phosphorus and Carbohydrates

Phosphorus plays an essential part in carbohydrate metabolism in

phoshoryalation

of

glycogen.Phosphorus

is an essential constituent of coenzyme I and co-

carboxylase

enzyme system in the oxidation of carbohydrate , fat and protein.

.

5.Copper and Fiber

Dietary fiber do not inhibits copper absorption.

6.Chromium and Carbohydrates

The high sugar diet enhanced urinary chromium losses

7.Magnesium and carbohydrates

Magnesium deficiency has been linked to insulin resistance and metabolic syndrome because

magnisium

is required for CHO metabolism.

Increased intakes of dietary fiber have been reported to decrease magnesium utilization in humans presumably by decreasing absorption.

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Vitamin- Carbohydrates inter-relations

Vitamin –C and Carbohydrate

Vitamin –

C has been found to affect the regulating CHO metabolism either at the level of rate of absorption of CHO from intestine ,or of glycogen level alteration of liver and other tissues . It has been found that in scorbutic animals ,there is a diminution of glutathione levels with simultaneously depression in insulin secretion. This is due to the reason as there is an increase in

dehydro

ascorbic level in tissues which may combine with

sulfydral

groups of glutathione making it unavailable for the protective role in beta cells of pancreas and causes diminished insulin secretion.

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There is a severe depression in

hexokinase

activity and in the turnover rate of

phosphorylated

intermediates of CHO metabolism in scorbutic conditions.

A depression in

phosphoglucomutase

and

phosphohexoseisomerase

activity with stimulation in glucose -6-phosphate

dehydrogenase

activity were

noted

.

The

depression in glycogen synthesis in scurvy was mostly due to the limiting availability of

uridine

triphosphate

and the diminished activities of

hexokinase

and

phosphoglucomutase

under vitamin-C deprivation . In scorbutic conditions, there is also a depression in the TCA cycle and electron transport chain

whee

V-C act as electron acceptor and its function is highly specific.

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2.Biotin and Carbohydrate

Replacing glucose in the diet with other carbohydrates of low molecular weight like

sorbitol

and fructose elevates the severity of biotin

deficiency.Since

glucose utilization is impaired ,it is likely that provision of other CHO, improves the energy supply.

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LIPID-LIPID INTER-RELATIONSHIPS

Lipids may be regarded as organic substances relatively insoluble in water ,soluble in organic solvents (

alcohol,ether

etc ) ,actually or potentially related to fatty acids and utilized by the living cells.

Lipids are the concentrated form of energy.

Lipid

lipid

interaction is that in which TRANS FATTY acids inhibit the

desaturation

and elongation of

linoleic

acid and alpha –

linolenic

acid to form long chain essential fatty acids .

Trans fatty acid -----

Linoleic

acid --------- alpha –

linolenic

acid----

Essential fatty acid

Trans fatty acids

The food industry incorporates fats and oils into margarines ,

biscuits,cake,chocolates

and other manufactures

products.Food

manufactures use fats and oils that have been

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altered by the process of

hydrogenation,i.e

. adding hydrogen

atoms to the double bonds in monounsaturated fatty acids and polyunsaturated fatty acids in order to increase the degree of saturation of fatty acids in the oils.

Hydrogenation changes the configuration of some monounsaturated fatty acids and polyunsaturated fatty acids.

Cis

fatty acids have two hydrogen atoms attached to the carbon on the same side of the double bond and molecule bends at the double

bond.In

trans fatty acids , the hydrogen atoms are placed on the opposite sides of the double bond and the molecule stays straight at the double bond.

Trans fatty acids behave biologically as saturated fats rather than like

cis

unsaturated fatty acids .The bulk of trans fatty acids in hydrogenated fats are monounsaturated fatty acid –

Eladic

acid which is trans equivalent to oleic acid.

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Most of the dietary intake of fatty acids is derived from margarine ,

dalda

and other foods manufactures from hydrogenated fats.

Saturated and short chain fatty acids

Stearic

acid is a saturated fatty acid with no double bond .

It lowers the HDL but does not raise serum cholesterol reducing both total and saturated fat.

Short chain fatty acids are organic

anoins

predominantly acetate , butyrate and propionate. In the

caecum

, these exist in the production of 70%, 20% and 10% respectively.

Short chain fatty acids are produced by the colonic bacteria from unabsorbed

carbohygrates

. They are utilized as a source of energy by large intestine and stimulate its mucosal growth . The fatty acids hydrolyzed from short chain fatty acids are transported to the liver as free acids via the portal vein. They enter the mitochondria of the liver cells and are

oxidised

rapidly.

Short chain fatty acids Carbohydrates Large intestine

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Protein- Lipids inter- relationships

Starvation Conditions

If

gluconeogenesis

were to

contiue

at accelerated rate during early starvation ,skeletal muscles would soon be exhausted. An adaptation in lipid metabolism occurs in long term starvation so that

ketone

bodies (

acetoacetate

, beta

hydroxybutyrate

) are formed.

Ketone

bodies cross blood barrier to provide energy to brain and thereby spare body protein from degradation .Production and utilization of these

ketone

bodies result in reduction in protein degradation and oxidation of amino acids . These adaptations help conserve both energy and amino acids and is reflected in output of nitrogen in urine , which is decreased from 12gms in early starvation to 3gms nitrogen per day by several weeks of starvation .

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When body fats stores are exhausted , body protein is again mobilized for energy by means of an increase in muscle protein degradation .This final increase in degradation of body protein cannot be sustained for long if feeding does not occur and death ensues.

2.Methionine and

choline

The most abundant phospholipids in eukaryotic cells are

phosphatidylcholine

and

phosphatidylethanolamine

. Both can be synthesized from

phosphatidylserine

or through alternative pathways that start with free

choline

or ethanolamine respectively. 3 methyl groups of

choline

are derived from amino acid

methionine

.

Choline

Phosphoatidycholine

/

phosphatidyethanolamine

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3. Glucagon and Lipid

Glucagon promotes fatty acid oxidation resulting in energy production and

ketone

body synthesis .

Fatty acid

___oxidation_______

ATP +

ketone

bodies

Fat – Mineral inter-relation

1. Fats and Calcium

An individual suffering from fat

malabsorption

shows decreased calcium absorption due to the formation of fatty acid soaps which are not absorbed and are excreted in

faeces

as ca soaps.

Fat intake has a negative impact on ca balance only during

steaorrhoea

. Ca forms insoluble soaps with fatty acids in the gut

.

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2.Lipids and Phosphorus

Phosphorus is bound with lipids to form

phospholipids,like

lecithin and

cephlain

, which are present in every cell membrane in the body

These are the integral part of cell structure and also act as an intermediate in fat transport and absorption.

3.Iron and Fats

Poor fat digestion leads to

steaorrhoea

which also leads to a decrease in iron absorption.

4.Fats and Sodium

Bacterial action on CHO and fibers in large bowel generates short chain fatty acids: acetate, propionate and butyrate. These are widely absorbed and stimulates sodium absorption.

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Fat – Vitamin inter-relation

1.Vitamin -c and Cholesterol

a) Ascorbic acid participates in hydroxylation of certain steroid hormones synthesis in adrenal

tissues.V

- C con. decreases in periods of stress when adrenal cortical hormone activity is high .

V-C

when

Adernal

cortical hormone

During periods of emotional , psychological stress , urinary excretion of V – C

inreacses

.

b) The rate limiting step of bile acid synthesis in liver involves the

Cholesterol

7- alpha-

hydroxylase

The activity of this pathway is reduced in V – C deficient animals and is associated with elevated plasma cholesterol con. This leads to

hypercholesterolemia.

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3. Vitamin –A and Fat

Retinoids

and

Cartenoids

are incorporated into micelles along with other lipids for passive absorption into mucosal cells of small intestines . These then are incorporated

chylomicrons

for transport

lymph

and eventually

blood stream

which then finally pass to

liver

and

tissues

.

The absorption of alpha ,beta, gamma ,carotene (

provitamin

A ) requires fat.

In the absence of fat in diet , they are not absorbed .

Rancid fats destroy the

vitamin A

and

beta carotene

present in the diet.

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2.V- D and Cholesterol

2 sterols

one in lipids of animals i.e

. 7-dehydrocholesterol

and one in plants

i.e

ergosterol

- serve as

precursor of V- D

And

7-dehydrocholesterol

under UV rays

cholecalciferol

(vitamin-D3).

Ergosterol

Ergocalciferol

(Vitamin D2)

Then these D2 and D3 require further metabolism to yield metabolically active form of 1,25

dehydroxy

vitamin D or

cacitriol

.

Dietary vitamin D is incorporated into other lipids into

micells

and absorbed with lipids in intestine. Inside absorptive cells, vitamin is incorporated into

chylomicrons

, enters lymphatic system and subsequently enters

plasma,where

it delivered to cells.

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4. Vitamin E and Fat

Tocopherols

act as antioxidant i.e. they can prevent the oxidation of various other oxidized substances such as fats and vitamin –A.

It is located in the lipid portion of cell membranes it protects unsaturated phospholipids of the membrane from oxidative degradation from highly reactive oxygen species and other free radicals .Vitamin E perform this function through its ability to reduce such

radicls

into harmless metabolites by donating a hydrogen to them . This process is called free radicals scavenging

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As a membrane free radicals scavenger, V – E is an important component of the cellular antioxidant

defence

system which involves other enzymes such as

SOD(superoxide

dismutases

), glutathione

peroxidases

(

GPxs

), GR ( glutathione

reductase

,

catalase

and

also non enzyme factors many of which depends on other essential nutrients. For

eg

–

GSHxs

, and TR depend on

on

slenium

status

etc . So, the antioxidant function of vitamin E can be affected by the levels of many other nutrients.

Fatty acids with 2 or more double bonds i.e. polyunsaturated fatty acids are abundant in cell membrane and have important

infulence

on membrane fluidity and function . However , their double bonds make them susceptible to oxidation by free radicals .

Fortunately ,

most V – E in body is found in cell membrane where it functions to protect polyunsaturated fatty acids from free radical attack

.V- E stabilizes free radicals and prevent it from reacting with adjacent polyunsaturated

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fatty acids.

Also plasma lipoproteins, like cell membrane , contain an abundance of lipid including proportions of polyunsaturated fatty acids .

They also contain fat soluble V- E which plays an essential role in protecting lipoproteins from oxidative damage.

This is particularly important in low density lipoproteins (LDL) because lipid peroxides can oxidize

apolipoprotein

B resulting in formation of

oxidatively

modified LDL.

apolipoprotein

B

LDL

This oxidized LDL accumulates in walls of arteries at greater rate than normal LDL which is non

oxidised

, thus accelerating development of

artherosclerotic

plaques

.

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Morover

, V – E is absorbed in manner similar to most other dietary lipids and requires fat digestion to be functioning normally.

The presence of fat in small intestine enhances V – E absorption because the products of triglyceride breakdown into gut promote the formation of mixed

micells

, the vehicle from which V – E is absorbed into the mucosal cell lining of the small intestine.

Lack of the bile acids or fat digestive enzymes damage to gastrointestinal wall or inability to synthesize

chylomicrons

which will decrease V – E absorption

.

Disease in which V – E absorption is reduced includes pancreatic diseases and sometime other genetic inability to make

chylomicrons

.

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5.

Vitamin K and Fat

Like other fat soluble vitamin absorption of V - K is also depends upon on minimum amount of dietary fat and on bile salts and pancreatic juices . The absorbed V – K is incorporated to

chylomicrons

in lymph and taken to liver , where are incorporated VLDL and subsequently delivered to

to

peripheral tissues by LDL.

V- K

Chylomicrons

(lymph --- liver )

VLDL Tissues (LDL)

6. Fat and

Choline

Choline

is a methyl rich essential component of animal tissues , where it is a structural unit of lecithin (i.e.

phosphatidylcholine

or phospholipids containing

choline

which is a part of bile where it emulsifies fats and is a part of lipoprotein also) and neurotransmitter acetylcholine. Thus

choline

is widely distributed in fats , existing predominantly in form of lecithin in eggs , liver,

soyabeans

, beef , milk and peanuts.

Choline

has several functions:

Slide40

As

phosphatidycholine

, it is a structural element of membrane.

A precursor to

spingolipids

( lipids esters attached to

spingosine

base rather than glycerol and present in nervous system of animals and membrane of plants and lower eukaryotes such as yeast)

A promoter to lipid transport

As acetylcholine , it is a neurotransmitter.

It functions as emulsifier in bile ,

thues

helping with absorption of fat i.e.

lipotropic

factor and prevents accumulation of fat in liver i.e. it prevents fatty liver.