Nutrition and Nutritional Biochemistry: Lipids
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Questions and Answers

What percentage of the body weight is lipids in a healthy 70kg person?

  • 5-10%
  • 30-40%
  • 20-30%
  • 10-20% (correct)

    • What is the caloric function of Triacylglycerol (TG)?

  • 10 Cal of energy / g
  • 9 Cal of energy / g (correct)
  • 7 Cal of energy / g
  • 4 Cal of energy / g

    • What is the main characteristic of Medium Chain Triacylglycerol?

  • Medium chain with 8-10 Cs (correct)
  • Very long chain with 20-24 Cs
  • Short chain with 4-6 Cs
  • Long chain with 16-20 Cs

    • Where are Medium Chain Triacylglycerol metabolized?

    <p>Liver</p> Signup and view all the answers

    Which of the following fatty acids are found in milk?

    <p>SFA range from C4 to C18</p> Signup and view all the answers

    What is the main classification of fatty acids based on their chemical structure?

    <p>Saturated, Monounsaturated, and Polyunsaturated</p> Signup and view all the answers

    What is the main characteristic of Polyunsaturated fatty acids (PUFA)?

    <p>Multiple double bonds</p> Signup and view all the answers

    What is the primary source of Medium Chain Triacylglycerol?

    <p>Coconut oil and Palm kernel oil</p> Signup and view all the answers

    Which of the following foods is a source of arachidonic acid?

    <p>Peanut oil</p> Signup and view all the answers

    What is the major monounsaturated fatty acid in our diet?

    <p>Oleic acid (C18:1n-9)</p> Signup and view all the answers

    What is the characteristic of oleic acid?

    <p>It has one double bond and is an omega-9 fatty acid</p> Signup and view all the answers

    What is the ideal ratio of omega-6 to omega-3 fatty acids in the human diet?

    <p>~1</p> Signup and view all the answers

    Which of the following is an example of an omega-3 fatty acid?

    <p>Alpha-linolenic acid (ALA 18:3n-3)</p> Signup and view all the answers

    What is the source of Docosahexaenoic acid (DHA)?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of a higher omega-6/omega-3 ratio on health?

    <p>It promotes the pathogenesis of many diseases</p> Signup and view all the answers

    What is the number of double bonds in Eicosapentaenoic acid (EPA)?

    <p>Five</p> Signup and view all the answers

    What is the main source of trans fatty acids in the diet?

    <p>Partially hydrogenated fats and fried foods</p> Signup and view all the answers

    What is the effect of omega-3 fatty acids EPA and DHA on triglyceride hepatic synthesis?

    <p>They lower triglyceride hepatic synthesis</p> Signup and view all the answers

    Which of the following fatty acids is not essential?

    <p>Oleic acid (cis18:1n-9)</p> Signup and view all the answers

    What is the reason why mammalian cells cannot convert omega-6 to omega-3 fatty acids?

    <p>They lack the converting enzyme, omega-3 desaturase</p> Signup and view all the answers

    What is the benefit of omega-3 fatty acids in terms of chronic inflammation?

    <p>They can fight chronic inflammation</p> Signup and view all the answers

    Which of the following oils is a source of oleic acid?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is a source of Linoleic acid (LA)?

    <p>Soy bean oil</p> Signup and view all the answers

    What is the number of double bonds in Alpha-linolenic acid (ALA)?

    <p>Three</p> Signup and view all the answers

    What is one way omega-3s can reduce chronic inflammation?

    <p>By reducing the production of cytokines as interleukin 6</p> Signup and view all the answers

    How do EPA and DHA reduce blood pressure?

    <p>By directly increasing K+ channels currents</p> Signup and view all the answers

    What is the typical range of reduction in triglycerides serum level by omega-3s?

    <p>15-30%</p> Signup and view all the answers

    What is the effect of omega-3s on 'good' HDL cholesterol?

    <p>Raise HDL cholesterol levels</p> Signup and view all the answers

    What is the effect of omega-3s on nitric oxide?

    <p>Promote the release of nitric oxide from endothelial cells</p> Signup and view all the answers

    What is the term for the amount of blood pressure in arteries during contraction?

    <p>Systolic blood pressure</p> Signup and view all the answers

    How do omega-3s reduce triglycerides serum level?

    <p>By reducing hepatic synthesis of VLDL and accelerating degradation of fatty acids and triglycerides clearance</p> Signup and view all the answers

    What is the benefit of omega-3s in reducing chronic inflammation?

    <p>Improving risk factors for cardiovascular diseases and heart stroke</p> Signup and view all the answers

    Study Notes

    Nutritional Aspect of Lipids

    • Lipids are present in the human diet and account for 10 to 20% of the body weight, with 90% of lipids stored in adipose tissues.
    • Lipids in the human diet come from animal and plant origins, consisting mainly of triacylglycerol, with some dissolved cholesterol and fat-soluble vitamins.

    Medium Chain Triacylglycerol

    • Medium chain triacylglycerol has a caloric value of 9 Cal/g, compared to 4 Cal/g for carbohydrates.
    • Medium chain triacylglycerol is used as an alternative source of fat energy, especially in cases where individuals are unable to digest or metabolize long-chain triacylglycerol.
    • Medium chain triacylglycerol is digested in the stomach, absorbed, and transported directly to the liver, where it is rapidly metabolized by beta-oxidation.
    • Medium chain triacylglycerol is found in coconut oil and palm kernel oil.

    Fatty Acids Classifications

    • Fatty acids can be classified into three categories: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA).

    Saturated Fatty Acids (SFA)

    • Major SFA in the diet include C14, C16, and C18, except in milk and coconut oil, where SFA range from C4 to C18.

    Monounsaturated Fatty Acids (MUFA)

    • Major MUFA in the diet is oleic acid (C18:1n-9).

    Polyunsaturated Fatty Acids (PUFA)

    • Major PUFA in the diet include linoleic acid (C18:2n-6) and alpha-linolenic acid (C18:3n-3).

    Omega-3 Fatty Acids Family

    • Omega-3 fatty acids include alpha-linolenic acid (ALA, 18:3 n-3), eicosapentaenoic acid (EPA, 20:5 n-3), and docosahexaenoic acid (DHA, 22:6 n-3).
    • Omega-3 fatty acids have three, five, or six double bonds, respectively.
    • Omega-3 fatty acids are essential and cannot be synthesized by the human body.

    Omega-6 Fatty Acids Family

    • Omega-6 fatty acids include linoleic acid (LA, 18:2 n-6) and arachidonic acid (AA, 20:4 n-6).
    • Omega-6 fatty acids have two or four double bonds, respectively.
    • Omega-6 fatty acids are essential and cannot be synthesized by the human body.

    Omega-9 Fatty Acids Family

    • Omega-9 fatty acids include oleic acid (18:1n-9), which has one double bond.
    • Main sources of oleic acid are olive, canola, avocado, and oilseeds.

    Ratio of Omega-6 to Omega-3 Fatty Acids

    • The ideal ratio of omega-6 to omega-3 fatty acids in the diet is approximately 1:1.
    • A higher ratio of omega-6 to omega-3 fatty acids has been linked to various diseases, including cardiovascular disease, cancer, osteoporosis, and inflammatory and autoimmune diseases.

    Trans Fatty Acids (TFA)

    • Main sources of trans fatty acids are partially hydrogenated fats and fried foods.
    • A small proportion of trans fatty acids also comes from ruminant animals (fat and whole milk).

    Effect of Dietary Lipid on Lipid Metabolic Pathways

    • Omega-3 fatty acids EPA and DHA decrease triglyceride hepatic synthesis and increase beta-oxidation in the liver.

    Benefits of Omega-3 Fatty Acids

    • Omega-3 fatty acids can reduce chronic inflammation by enzymatic competition for eicosanoids synthesis, reducing expression of cell adhesion molecules, and suppressing production of cytokines such as interleukin 6.
    • Omega-3 fatty acids can improve risk factors for cardiovascular diseases and heart stroke by:
      • Reducing blood pressure
      • Reducing triglycerides
      • Raising HDL cholesterol levels
      • Promoting release of nitric oxide from endothelial cells.

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    Description

    This quiz covers the nutritional aspects of lipids, including their caloric function, classification, and effects on metabolic pathways. It also explores the benefits of Omega-3 fatty acids.

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