Fats

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Fats

  1. 1. Fats
  2. 2. Why do we need fats? • Contribute to texture and taste • Increase palatability of diet • For meeting the needs of essential fatty acids (linoleic acid n – 6 and linolenic acid n – 3) • Rich source of energy • Promote absorption of fat soluble vitamins • Impart a feeling of fullness and satisfaction and thus delay onset of hunger.
  3. 3. Essential Fatty Acids • Queen of Vitamins • Poly Unsaturated Fatty Acids (PUFA) • Linoleic acid (C18:2/n-6/PUFA) and α Linolenic acid (C18:3/n-3/PUFA) – must be present in a ratio of 5:1 to 10:1 • Omega 6 to Omega 3 (n6 : n3) ratio of 5:1 is desirable
  4. 4. Essential Fatty Acids • High Omega 6 and low omega 3 ratio as in ground nut, sunflower, safflower oils (56:1) can predispose to – free radical injury, – angiotoxicity, – impaired immune function, – reduced glucose tolerance, – increased platelet aggreagation and – albuminuria
  5. 5. Essential Fatty Acids • Omega 6 and Omega 3 ratio – In coconut oil, [PUFA is only 2%] but this ratio is <5:1 (but more MCTs) – In ghee it is 3:1 – Mustard oil 1.5:1
  6. 6. Essential Fatty Acids • Omega 3 or n-3 – In coconut oil, [PUFA is only 2%] but this ratio is <5:1 (but more MCTs) – In ghee it is 3:1 – Mustard oil 1.5:1
  7. 7. Long Chain Fatty Acids EFAs are converted to LCFAs by a series of chemical reactions called elongation and desaturation. • LCPs from n-6 series derived from linoleic acid are – arachidonic acid (ARA) and – adrenic acid (ADA). • LCPs from n-3 series derived from alpha linoleic acid are – ecosa pentanoic acid (EPA) and – decosa hexanoic acid (DHA).
  8. 8. Long Chain Fatty Acids EFAs are converted to LCFAs by a series of chemical reactions called elongation and desaturation. • LCPs are the building blocks of brain lipid. • Deficiency of LCPs may lead to comorbid conditions like dyslexia, dyspraxia and hyperactivity
  9. 9. Types of fat • Visible : – Fats that are used as such at the table or in cooking • Eg: Veg. oils, vanaspathi, ghee,butter etc. • Invisible : – Fats that are present as and integral components of different foods • Eg. : cereals, animal foods
  10. 10. Component of fat • Total should be 15 – 30 % and 1-3 % of calories should be from EFAs • Avg. Indian foods supply 25-30% calories as fat. Diets of young children and adolescents should contain only 25 g/d of fat • Not more than 10% of energy should be from essential fatty acids /SFA and 10% should come from MUFA and 10% from PUFA
  11. 11. Fatty Acids - Types • Saturated: Lauric acid (C12), Myristic acid (C14), Palmitic acid (C16) and Stearic acid (C18) – Animal fats – Short and medium chained saturated FAs are easily absorbed – Excess of MCTs can be atherogenic • Monounsaturated fats: – Oils from palm, seseme, groundnut, cotton seed, olive.
  12. 12. Fatty Acids - Types • Polyunsaturated fats: – Only in plant foods – All vegetable oils rich in Linoleic (n-6) – α- linolenic (n-3) is present only in mustard and soyabean oils and as invisible oil in legumes/pulses, mustard and fenugreek seeds (methi) & GLVs – Fish and fish oils provide biologically more active form of n-3 linolenic acid
  13. 13. Fatty acid compositions Item SFA % MUFA % PUFA % n6 n3 Coconut oil 92 6 1.6 0.4 Corn oil 13 25 61 1 Groundnut oil 18 49 33 0 Olive oil 14 8 1 Sunflower oil 11 20 69 0 Safflolower oil 10 13 77 0 Palmolein 40 48 11 1 HVO 76 19 3 2
  14. 14. SATURATED MONO UNSATURATED POLY UNSATURATED LINOLEIC (N - 6) LIONOLENIC (N-3) •Coconut •Palm kernel •Ghee •Butter •Vanaspathi •Red palm oil •Palmolein •Groundnut •Ricebran •Saseme Low: • Red palm oil •Palmolein Medium: •Groundnut •Ricebran •Seseme •Mustard •Soya bean
  15. 15. Medium Chain Triglycerides • C8 - C10 Fatty Acids • They are absorbed directly into the portal vein even during fat malabsorption.
  16. 16. Cholesterol • Essential component of body tissues and lipoproteins • Forms nearly 0.2 % of body weight • It has no calorific value • Hypercholesterolemia – esp. LDL predisposes to coronary heart disease • Heredity, smoking, sedentary habit, emotional stress, hormonal imbalance, diet, diabetes etc. predispose to hypercholesterolemia.
  17. 17. Cholesterol • Endogenous : Synthesized from 2 carbon fragments like acetate, acetic acid, acetyl CoA, etc. • Exogenous : Derived from food
  18. 18. Cholesterol • Excess cholesterol is converted to bile acids and excreted into intestine and eliminated as coprosterol • Dietary fiber reduced cholesterol level • Cholesterol is present in bound and free forms in a ration of 1:3 • Bound to esters of fatty acids or lipoprotein (LDL) cholesterol – 70% • That bound to alpha lipoprotein is high density lipoprotein (HDL) cholesterol – 30% • Small amounts - bound to very low density lipoproteins (VLDL) and rest to intermediate low density lipoproteins (ILDL) and very high density lipoproteins (VHDL)

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