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IMPORTANCE OF IMPORTANCE OF LIPIDSLIPIDS

FUNCTIONS of Lipids (fatty FUNCTIONS of Lipids (fatty acids)acids)

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1. 1. Energy source & help in transportation:Energy source & help in transportation:

Lipids are Lipids are good source of energygood source of energy & provide & provide large amount of energy. It provide large amount of energy. It provide 9 kcal/g9 kcal/g approximately approximately 38 kilojoules38 kilojoules/g fat utilized. /g fat utilized.

Lipids in food also act as Lipids in food also act as carrier of fat-soluble carrier of fat-soluble vitaminsvitamins..

Lipids also make the food Lipids also make the food more palatablemore palatable & & serve to serve to decrease its massdecrease its mass..

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2. 2. Satiety Value:Satiety Value: The dietary lipids The dietary lipids decreasedecrease gastric motility & gastric motility &

secretions & have a secretions & have a highhigh satiety value. satiety value. 3. 3. Anatomical stability:Anatomical stability: Body fat provides Body fat provides contourcontour to the body & also to the body & also

gives anatomical gives anatomical stabilitystability to the organ like to 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 this is the best suited for this

purpose due to its purpose due to its very little watervery little water content & content & high energyhigh energy content. content.

5. 5. Electric Insulator:Electric Insulator: Lipids act as Lipids act as electric insulatorselectric insulators in the nervous in the nervous

tissue allowing tissue allowing rapid transmissionrapid transmission of action of action potential (depolarization waves or nerve potential (depolarization waves or nerve impulses).impulses).

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6. 6. Important Cellular Constituents:Important Cellular Constituents: They take part in the They take part in the formation of plasma formation of plasma

membranemembrane present around the whole cell present 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 important Some lipids act as precursor of very important

physiological compounds. e.g. physiological compounds. e.g. cholesterolcholesterol is is the the precursorprecursor of steroidal hormones (adrenal of 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 in Presence of lipids like cholesterol & other in

the skin makes it the skin makes it highly resistanthighly resistant to the to the absorption of absorption of water-soluble substanceswater-soluble substances & also & also to the action of to the action of many chemicalsmany chemicals. .

Lipids prevent water evaporation from the Lipids prevent water evaporation from the skin; skin; without thiswithout this protection the amount of protection the amount of daily loss of water would probably be daily loss of water would probably be 15-20 lts15-20 lts instead of instead 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 in have a role in

the transmission of the nerve impuses the transmission of the nerve impuses across across synapsessynapses as they form part of the as they form part of the receptorsreceptors. .

These lipids also concerned with These lipids also concerned with blood group blood group specificityspecificity..

10. 10. Sterol derivatives:Sterol derivatives: Vitamin DVitamin D play an important role in the play 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 lipid The 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 important Ceramide is an important second messengersecond messenger

which which regulateregulate pathways such as the cell cycle, pathways such as the cell cycle, aging etc. 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.

Rapeseed Rapeseed = 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 in waxy 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 powerful NaOH sol. Nickel is left in the form of spongy mass which is more powerful catalyst especially for hydrogenation. catalyst especially for hydrogenation.