Lipids serve many important functions in the body. They provide a major source of energy, act as carriers for fat-soluble vitamins, and help with the absorption of important nutrients. Lipids also provide structure and stability to cells as important components of membranes, and serve as precursors to hormones and other physiological compounds. In addition, lipids play roles in insulation, contour and stability of organs, energy storage, and transmission of nerve impulses.

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IMPORTANCE OFIMPORTANCE OF
LIPIDSLIPIDS
FUNCTIONS of Lipids (fattyFUNCTIONS of Lipids (fatty
acids)acids)

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 1.1. Energy source & help in transportation:Energy source & help in transportation:
 Lipids areLipids are good source of energygood source of energy & provide& provide
large amount of energy. It providelarge amount of energy. It provide 9 kcal/g9 kcal/g
approximatelyapproximately 38 kilojoules38 kilojoules/g fat utilized./g fat utilized.
 Lipids in food also act asLipids in food also act as carrier of fat-solublecarrier of fat-soluble
vitaminsvitamins..
 Lipids also make the foodLipids also make the food more palatablemore palatable &&
serve toserve to decrease its massdecrease its mass..

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 2.2. Satiety Value:Satiety Value:
 The dietary lipidsThe dietary lipids decreasedecrease gastric motility &gastric motility &
secretions & have asecretions & have a highhigh satiety value.satiety value.
 3.3. Anatomical stability:Anatomical stability:
 Body fat providesBody fat provides contourcontour to the body & alsoto the body & also
gives anatomicalgives anatomical stabilitystability to the organ liketo the organ like
kidneys.kidneys.

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 4.4. Energy ReservoirEnergy Reservoir::
 Fats (Fats (triglycerolstriglycerols) are good energy reservoirs) are good energy reservoirs
in the body.in the body.
 Adipose tissueAdipose tissue is the best suited for thisis the best suited for this
purpose due to itspurpose due to its very little watervery little water content &content &
high energyhigh energy content.content.
 5.5. Electric Insulator:Electric Insulator:
 Lipids act asLipids act as electric insulatorselectric insulators in the nervousin the nervous
tissue allowingtissue allowing rapid transmissionrapid transmission of actionof action
potential (depolarization waves or nervepotential (depolarization waves or nerve
impulses).impulses).

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 6.6. Important Cellular Constituents:Important Cellular Constituents:
 They take part in theThey take part in the formation of plasmaformation of plasma
membranemembrane present around the whole cellpresent around the whole cell
((GlycolipidsGlycolipids), nucleus & membrane around), nucleus & membrane around
different organs in the body.different organs in the body.
 7.7. As precursors:As precursors:
 Some lipids act as precursor of very importantSome lipids act as precursor of very important
physiological compounds. e.g.physiological compounds. e.g. cholesterolcholesterol isis
thethe precursorprecursor of steroidal hormones (adrenalof steroidal hormones (adrenal
cortex & gonadal hormones).cortex & gonadal hormones).

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 8.8. Prevention in absorption & loss of subst.Prevention in absorption & loss of subst.
 Presence of lipids like cholesterol & other inPresence of lipids like cholesterol & other in
the skin makes itthe skin makes it highly resistanthighly resistant to theto the
absorption ofabsorption of water-soluble substanceswater-soluble substances & also& also
to the action ofto the action of many chemicalsmany chemicals..
 Lipids prevent water evaporation from theLipids prevent water evaporation from the
skin;skin; without thiswithout this protection the amount ofprotection the amount of
daily loss of water would probably bedaily loss of water would probably be 15-2015-20
ltslts instead ofinstead of 300-400ml300-400ml..

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 9.9. Transmission of nerve impulses:Transmission of nerve impulses:
 Sphingosine-containing lipidsSphingosine-containing lipids have a role inhave a role in
the transmission of the nerve impusesthe transmission of the nerve impuses acrossacross
synapsessynapses as they form part of theas they form part of the receptorsreceptors..
 These lipids also concerned withThese lipids also concerned with blood groupblood group
specificityspecificity..
 10.10. Sterol derivatives:Sterol derivatives:
 Vitamin DVitamin D play an important role in theplay an important role in the
metabolism of calcium & phosphorous.metabolism of calcium & phosphorous.
 Bile acidsBile acids help in lipid digestion & absorption.help in lipid digestion & absorption.

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 11.11. Action on platelets:Action on platelets:
 The platelet-activating factor is a lipidThe platelet-activating factor is a lipid
((PlasmalogenPlasmalogen) that aggregates platelets & has) that aggregates platelets & has
many other functions.many other functions.
 12.12. Ceramides:Ceramides:
 Ceramide is an importantCeramide is an important second messengersecond messenger
whichwhich regulateregulate pathways such as the cellpathways such as the cell
cycle, aging etc.cycle, aging etc.

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 13.13. Terpenes:Terpenes:
 Vtiamin AVtiamin A – help in vision & epithelial– help in vision & epithelial
integrity.integrity.
 Vitamin EVitamin E (Tocopherol) – acts as lipid(Tocopherol) – acts as lipid
antioxidant.antioxidant.
 Vitamin KVitamin K – participate in blood coagulation.– participate in blood coagulation.

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 References and keys:References and keys:
 Dr.M.Rafiq, and Muashtaq Ahmad.Dr.M.Rafiq, and Muashtaq Ahmad.
 RapeseedRapeseed = oil seed plant of mustard family -Brasica napus= oil seed plant of mustard family -Brasica napus
 SpermacetiSpermaceti == waxy solid from sperm whales: a white waxy solid. Source: oil inwaxy solid from sperm whales: a white waxy solid. Source: oil in
the head of sperm whales and other cetaceans.the head of sperm whales and other cetaceans.
 Raney nickleRaney nickle = special form of nickel prepared by treating Al – Ni alloy with= special form of nickel prepared by treating Al – Ni alloy with
NaOH sol. Nickel is left in the form of spongy mass which is more powerfulNaOH sol. Nickel is left in the form of spongy mass which is more powerful
catalyst especially for hydrogenation.catalyst especially for hydrogenation.