the lipids triglycerides phospholipids and sterols l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
The Lipids: Triglycerides, Phospholipids, and Sterols PowerPoint Presentation
Download Presentation
The Lipids: Triglycerides, Phospholipids, and Sterols

Loading in 2 Seconds...

play fullscreen
1 / 36

The Lipids: Triglycerides, Phospholipids, and Sterols - PowerPoint PPT Presentation


  • 575 Views
  • Uploaded on

The Lipids: Triglycerides, Phospholipids, and Sterols. Chapter 5. Introduction. Poor health from fat consumption is seen when a person consumes either Too much fat Too little fat Too much of some kinds of fat Lipids = Fat Family of lipids Triglycerides (TG) (fats & oils)* Phospholipids

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Lipids: Triglycerides, Phospholipids, and Sterols' - maine


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
introduction
Introduction
  • Poor health from fat consumption is seen when a person consumes either
      • Too much fat
      • Too little fat
      • Too much of some kinds of fat
  • Lipids = Fat
    • Family of lipids
      • Triglycerides (TG) (fats & oils)*
      • Phospholipids
      • Sterols
chemist s view of fatty acids and triglycerides
Chemist’s View of Fatty Acids and Triglycerides
  • Lipids =
    • TG, Phosolipids, and sterols
  • Composed of C, H, and O
  • Have more C & H = supply more E per gram
  • Most are TG w/ glycerol backbones and three fatty acids (f.a.)
chemist s view of fatty acids and triglycerides4
Chemist’s View of Fatty Acids and Triglycerides
  • F.A. vary in C chain lengths, degree of unsaturation, and # of double bonds (d.b.)
  • Trans-fatty acids
chemist s view of fatty acids and triglycerides5
Chemist’s View of Fatty Acids and Triglycerides
  • Preview of lipids
    • Triglycerides: glycerol and 3 fatty acids
    • Fatty acids: even number of carbons
        • 4-24Cs; 18C most common in foods
        • Saturated or unsaturated
        • Mono or polyunsaturated
chemist s view of fatty acids and triglycerides6
Chemist’s View of Fatty Acids and Triglycerides
  • Fatty acids
    • Organic acid
    • Methyl group (CH3) at one end; acid group (COOH) at other
    • Usually even number of Cs
    • Saturation
chemist s view of fatty acids and triglycerides7
Chemist’s View of Fatty Acids and Triglycerides
  • Unsaturated
    • Monounsaturated f.a. :
      • Lack 2H atoms & have 1 d.b.
      • When most of the f.a.s are monounsat its called a monounsaturated fat
    • Polyunsaturated f.a.s (PUFA)
      • Lack 4 or more Hs & have at least 2 or more d.b.
      • When most of the f.a.s are polyunsaturated its called a polyunsaturated fat
chemist s view of fatty acids
Chemist’s View of Fatty Acids

Location of d.b.

    • Nearest the methyl end of the carbon chain
    • Assigned an Omega number
    • Omega- 3-polyunsat f.a.
      • Linolenic acid are essential f.a.
        • Soybean and canola oils, flaxseed, walnuts
    • Omega- 6-polyunsat f.a.
      • Linoleic acids are essential f.a.
        • Vegetable, i.e. sunflower, safflower, corn, and soy bean oils
  • Monounsaturated fatty acids
    • Omega-9 groups
      • Oleic acid most predominate in diet
        • Olive, canola oils
chemist s view of fatty acids and triglycerides9
Chemist’s View of Fatty Acids and Triglycerides
  • Triglycerides
    • Three fatty acids attached to Glycerol backbone
    • Formed via series of condensation reactions
    • Usually contain mixture of fatty acids
chemist s view of fatty acids and triglycerides11
Chemist’s View of Fatty Acids and Triglycerides
  • Degree of unsaturation
    • Firmness
      • Polyunsaturated fats
      • Saturated fats
      • Length of carbon chain
    • Stability
      • Sat fat is more resistant to oxidation
      • monounsat fat is slightly less susceptible to spoilage
      • Polyunsat fat spoils most readily
      • Protection from rancidity:
chemist s view of fatty acids and triglycerides12
Chemist’s View of Fatty Acids and Triglycerides
  • Degree of unsaturation
    • Hydrogenation
    • Trans-fatty acids
chemist s view of phospholipids and sterols
Chemist’s View of Phospholipids and Sterols
  • Phospholipids
    • Contain glycerol, 2 f.a. and a phosphate group with a molecule of choline
    • Solubility in fat and water
    • Emulsifiers in food industry
    • Roles
chemist s view of phospholipids and sterols16
Chemist’s View of Phospholipids and Sterols
  • Sterols
    • Food sources
      • Cholesterol
      • Plant sterols
    • Roles of sterols
      • Starting material for bile acids, sex hormones, adrenal hormones, and vit. D
      • Structural component of cell membranes
      • Liver produces 800-1500mg cholesterol per day
      • Atherosclerosis
lipid digestion
Lipid Digestion
  • Fats are hydrophobic
    • Tend to separate from watery fluids in GI tract
    • Digestive enzymes are hydrophilic
  • Goal of fat digestion
    • Dismantle triglycerides for body to absorb and use
lipid digestion19
Lipid Digestion
  • Mouth
    • Lingual lipase released by salivary glands
  • Stomach
    • Strong muscle contractions disperse fat into smaller droplets
    • Fat then exposed to Gastric lipase
lipid digestion20
Lipid Digestion
  • Small intestine
    • Cholecystokinin (CCK)
    • Pancreatic and intestinal enzymes
    • Phospholipids are hydrolyzed
    • Sterols are absorbed
    • Bile routes
    • Enterohepatic circulation
    • Soluble fibers are effective
      • in trapping some bile and
      • excreting it from the body thru the large intestine
lipid absorption
Lipid Absorption
  • Directly into bloodstream
    • Glycerol and short- & medium-chain fatty acids diffuse and are re-absorbed directly into the bloodstream
  • Lymphatic system
    • Larger molecules, Monoglycerides and long-chain f.a.s, form micelles that get reabsorbed, and are reformed into new triglycerides. With protein they are transported by chylomicrons
    • When packaged with protein it’s then transported so that cells all over body may select needed lipids
lipid transport
Lipid Transport
  • Lipid transport is made possible by a group of vehicles known as lipoproteins
  • Four main types of lipoproteins
    • Chylomicrons
    • Very-low-density lipoproteins (VLDL)
    • Low-density lipoproteins (LDL)
    • High-density lipoproteins (HDL)
health implications
Health implications
  • High LDL is associated with higher risk of heart attack and is known as a “bad” cholesterol
  • High HDL seems to have a protective effect and is known as “good” cholesterol
  • Factors that lower LDL and raise HDL
  • Genes influence lipopro activity
role of triglycerides
Role of Triglycerides
  • Provide the cells with energy
    • 9 kcalories per gram
  • Adipose tissue
    • Virtually unlimited ability to store fat energy in body
    • Secretes hormones
  • Skin insulation, shock absorption, cell membranes, and cell signaling pathways
essential fatty acids
Essential Fatty Acids
  • Linoleic acid – Omega-6 fatty acid
  • Linolenic acid – Omega-3 fatty acid
    • EPA & DHA-important for eyes, brain, and heart
  • Fatty acid deficiencies
    • Rare in US and Canada
    • Occur in infants and children with fat-free or low-fat diets
a preview of lipid metabolism
A Preview of Lipid Metabolism
  • Adipose cells store fat after meals
    • Lipoprotein lipase
    • Triglycerides reassembled inside adipose cells
  • Using fat for energy
    • Hormone-sensitive lipase inside the adipose cells hydrolyzes TG when needed for E
    • During fasting the body metabolizes fat, but requires CHO and pro for complete fat breakdown
    • Ketone bodies can be made from fat fragments
health effects of lipids
Health Effects of Lipids
  • Heart disease
    • Elevated blood cholesterol
      • Saturated fat
      • Dietary choices
      • Trans-fats
      • Dietary cholesterol
health effects of lipids32
Health Effects of Lipids
  • Heart disease
    • Monounsaturated fats
      • Replace saturated and trans fats
      • Reduces blood cholesterol
      • Dietary sources
    • Omega-3 fats
      • Benefits
      • Dietary sources
      • Omega-6 to omega-3 ratio
health effects of lipids33
Health Effects of Lipids
  • Cancer
    • Promotion rather than initiation of cancer
    • Dietary fat and cancer risk
  • Obesity
    • Cutting fat from diet reduces kcalories
recommended intakes of fat
Recommended Intakes of Fat
  • DRI and Dietary Guidelines
    • Diet low in saturated and trans fat
    • Diet low in cholesterol
    • 20 to 35 percent of daily energy from fat
  • AI set for linoleic and linolenic acids
  • Daily Values (DV) on food labels
    • Saturated fat and cholesterol
  • Risk of insufficient fat intake
from guidelines to groceries
From Guidelines to Groceries
  • Very lean and lean options of meat and meat alternative products
  • Fat-free and low-fat milk products
  • Wide variety of vegetables, fruits, and whole grains
  • Avoid invisible fat from high-fat cheese, baked & fried goods
  • Choose wisely from many available food products
from guidelines to groceries36
From Guidelines to Groceries
  • Fat replacers
    • Ingredients derived from CHO, pro, or fat
    • Replace fat in foods
    • Artificial fats offer sensory and cooking qualities but no kcalories.
      • Research on olestra supports its safety but it decreases the absorption of fat-soluble vits and may cause digestive distress in some
  • Read food labels
    • Total fat, saturated fat, trans fat, and cholesterol
    • Compare products
    • % Daily Value vs. % kcalories from fat