The%20Health%20Benefits%20of%20Fats

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The Health Benefits of Fats
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Quiz Yourself True or False

1. To lose weight, use regular, stick margarine
   instead of butter because it has 25 fewer
   kilocalories per teaspoon. T F
2. Egg yolks are a rich source of cholesterol. T F
3. Taking too many fish oil supplements may be
   harmful to health. T F
4. Increasing your intake of trans fats can reduce
   your risk of heart disease. T F

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How Did You Do?

1. False Regular stick margarine has about the same
   kcal/teaspoon as butter.
2. True Egg yolks are a rich source of cholesterol.
3. True Taking too many fish oil supplements may be
   harmful to health.
4. False The average American consumes about 1/3 of
   his/her daily energy intake from fat.
5. False Increasing your intake of trans fats may
   increase your risk of heart disease.

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A balanced picture of fats

• Is all fat bad for you?

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Dietary Lipids

• Triglyceridesthe major form of fat in food
• Phospholipidssimilar to triglycerides in basic
  structure contain phosphate containing groups
• Sterolsmainly cholesterol
• Fat-soluble vitamins (A, D, E, K)
• Some phytochemicals (carotenoids)

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Triglyceride Properties

• Concentrated source of energy (9 kcal/gm)
• Source of essential fatty acids
• Required for absorption of fat soluble vitamins
  by acting as a carrier in the small intestine
• Increase palatability and satiety value of foods
• Protection of organs and insulation

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Triglyceride
Composed of 3 fatty acid molecules bonded to a
glycerol molecule Composed of carbon, hydrogen,
oxygen
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Triglyceride Properties

• Contain less oxygen than carbohydrates so they
  contain more energy
• Insoluble in water Require emulsification by
  bile acids for adequate digestion

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Triglycerides Fatty Acids

• Fatty acids are composed of a chain of carbon
  atoms with a carboxyl (acid) group at one end.
• Hydrogen atoms are bonded to the carbons.
• Carbon chain length can vary.

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Fatty Acids The three types of fatty acids are
present in most food fats

• Saturated
• Animal fats (milk products, butter, meat)
• Coconut oil
• Palm and palm kernel oils
• Monounsaturated
• Olive oil
• Canola oil
• Peanut oil
• Safflower oil
• Polyunsaturated
• Most vegetable oils except palm kernel and
  coconut oils
• Nuts, seeds
• Chicken, turkey, fish

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Saturated Fat

• Saturatedno double bonds exist between carbons
  only single bonds between carbons
• Carbons are fully saturated with hydrogen atoms
  only single bonds exist between carbons
• Palmitic acid (16 carbons)the most abundant
  saturated fatty acid in foods

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Unsaturated Fatty Acids

• Monounsaturatedone double bond in the carbon
  chain
• Polyunsaturatedmore than one double bond in the
  carbon chain
• Short chain fatty acids 2 to 4 carbons
• Medium chain fatty acids 6 to 12 carbons
• Long chain fatty acids - 14 to 24 carbons

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Saturated fats

• Solid at room temperature
• Butter
• Lard
• Vegetable shortening (Crisco)
• Coconut oil
• Tend to raise blood cholesterol and increase
  heart disease risk. Can also increase insulin
  levels.
• Lowering dietary fat can lower cholesterol levels.

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Monounsaturated Fatty Acid

• One double bond exists in the carbon chain.
• Oleic acid (18 carbons, 1 double bond)the most
  abundant monounsaturated fatty acid in foods
• Oleic acid is an omega-9 fatty acid because the
  double bond occurs at the 9th carbon from the
  omega end of the molecule

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Monounsaturated Fatty Acids(MUFA) Properties

• Liquid at room temperature
• Olive oil
• Canola oil
• Tend to lower blood cholesterol if they replace
  saturated fat in the diet.

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Polyunsaturated Fatty Acids(PUFA) Structure

• More than one double bond exists in the carbon
  chain
• Linoleic acid (18 carbons, 2 double bonds)
• Linoleic acid is an omega-6 fatty acid because
  the double bond occurs at the 6th carbon from the
  omega end of the molecule. Its also known as an
  n-6 fatty acid.

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Polyunsaturated Fatty Acids(PUFA) Structure

• Another important PUFA
• Linolenic acid (18 carbons, 3 double bonds)
• Linolenic acid is an omega-3 fatty acid because
  the double bond occurs at the 3 rd carbon from
  the omega end of the molecule. Its also known as
  an n-3 fatty acid

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Polyunsaturated Fatty AcidsProperties

• Liquid at room temperature
• Most vegetable oils
• More chemically unstable
• Rancidity occurs more easily
• Tend to lower blood cholesterol and reduce heart
  disease risk.

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Food Sources of Fatty Acids

• Saturated
• Animal fats (milk products, butter, meat)
• Coconut oil
• Palm and palm kernel oils
• Monounsaturated
• Olive oil
• Canola oil
• Peanut oil
• Safflower oil
• Polyunsaturated
• Most vegetable oils except palm kernel and
  coconut oils
• Nuts, seeds
• Chicken, turkey, fish

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Essential Fatty Acids

• Two essential fatty acids
• Linoleic acid (an n-6 fatty acid)
• Linolenic acid (an n-3 fatty acid)
• They are called essential because they must be
  consumed to maintain good health.
• Both essential fatty acids are polyunsaturated.

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Essential Fatty AcidsGeneralFunctions

• Components of cell membranes
• Required for growth, reproduction, good skin
  integrity and wound healing
• Precursors of eicosanoids
• Eicosanoids are elongated (20C) highly
  unsaturated fatty acids
• Involved with reproductive functioning, immune
  system integrity, cell growth
• Optimize eicosanoids in the body by consuming a
  balanced ratio of essential fatty acids

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Linoleic n-6 Fatty Acid

• Unique properties
• Can reduce blood cholesterol and heart disease
  risk
• Does not reduce cancer risk
• Requirement Minimum of 3 of total kcal or a
  total of 60 kcal from linoleic acid. This amount
  is supplied by 1 tablespoon of soy oil.
• Typical American diet provides 7 of kcal as
  linoleic acid.
• Excessive intakes can suppress the immune system.
• Good food sources most vegetable oils, nuts,
  seeds, poultry, fish small amounts in egg yolk,
  whole grains.

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Linolenic n-3 Fatty Acid

• Unique functions and properties
• May be required for development of visual
  acuity
• Lowers blood triglycerides
• High intakes prolong bleeding time
• Anti-inflammatory properties
• Enhances the immune system
• May reduce heart disease and cancer risk In
  Japan, where n-3 fatty acid intake is much
  greater than in the US heart attacks are four
  times less common!

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Linolenic Acid

• Requirement Minimum of 0.5 of total kcal or a
  total of 10 kcal from linolenic acid. This amount
  is supplied by 1 tablespoon canola oil
• Good food sources flaxseed, English walnuts,
  canola oil, soy oil, ocean fish
• Also contained in egg yolk, dark green leafy
  vegetables, whole grains

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Linolenic acid

• The ratio of dietary linoleic and linolenic
• acids seems to be important for heart
• disease and cancer prevention.
• N-6/n-3 ratio tends to be high in the American
• diet (range from 101 to 501)
• Recommended ratio 41

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Ratio of Essential Fatty Acids

• Achieving a balanced ratio of essential FAs
  usually involves finding ways to increase
  linolenic acid
• Use primarily soy and canola oils (read food
  labels for these)
• Avoid hydrogenated oils (these lower the
  essential fatty acid content of vegetable oils)
• Avoid substituting reduced fat or fat free
  products for products containing linolenic acid
  (salad dressings)
• Maintain eggs in the diet
• Use some flaxseed
• Eat dark green leafy vegetables very often
• May include ocean fish in the diet

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Cis and Trans Fatty Acids

• 2 isomeric forms of fatty acids exist
• Cis and trans fatty acids have the same
  chemical formula, just a different configuration
  around the double bond.

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Cis and Trans Fatty Acids

• The TRANS configuration

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Cis and Trans Fatty Acids

• The cis configuration occurs most often in nature
• Trans configuration
• Occurs naturally in small amounts in some foods
  (beef, lamb, milk fat)
• Most trans FAs in foods are a byproduct of the
  industrial hydrogenation of vegetable oils.
  Hydrogenation adds hydrogens to unsaturated fatty
  acids to make them more saturated. This improves
  the stability of vegetable oils and makes them
  more solid at room temperature. In the
• process, the configuration of some double bonds
  changes from cis to trans. Hydrogenation is used
  in the production of margarine from oil.
• soybean oil
  soybean margarine

hydrogenation
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Trans Fatty Acids

• Americans eat about 5 g trans fat/day
• The problems with trans Fat
• Trans fatty acids do not relieve symptoms of
  essential fatty acid deficiency. In fact
  hydrogenation destroys some of the essential
  fatty acids in the oils. It also inactivates the
  vitamin K in the oil.
• Trans fatty acids act similarly to saturated
  fatty acids in raising blood cholesterol and
  insulin levels.
• Although the amount of trans fatty acid in most
  foods is less than the amount of saturated fatty
  acid, it is advisable to avoid them.

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Trans Fatty Acids (cont)

• Minimize intake of trans fatty acids by limiting
  intake of hydrogenated fats. Look for the word
  hydrogenated in the list of ingredients on the
  food label.
• Use vegetable oils and softer margarines as
  spreads and in recipes.
• Limit or avoid use of solid margarines, vegetable
  shortening (Crisco).
• Limit or avoid high fat commercial baked
  goodsdonuts, muffins, cookies, cakes.
• Limit or avoid restaurant fried foods, high fat
  foods.

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Summary- Types of Fats
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Why would it be undesirable to eliminatefat from
our diet?
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Answers

• We need essential fatty acids.
• Substrate for eicosanoid synthesis would be
  reduced.
• A fat free diet would greatly reduce the
  absorption of fat soluble vitamins and
  carotenoids.
• Fat provides a concentrated source of kcal.
• Eliminating fat would make it difficult to
  maintain a stable weight.
• Fat makes eating more pleasurable.

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How can we obtain a healthful balance offatty
acids in our diets?
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Graphics Microsoft Online, USDA Food and Nutrition Services Ingrid Adams, Ph.D., R.D. L.D. Associate Professor , Nutrition and Food Science, University of Kentucky Extension Specialist for Physical Activity and Weight Management Date February 27, 2015
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