1. Lipids FCS 342 Chapter 5

2. Outline Why we need fats in our diet Lipids, fats, and oils Major classes of lipids A closer look at fats: unsaturated, saturated, trans How to improve our diet Phospholipids and cholesterol Digestion of Fats Lipoproteins Dietary Fat Diet and disease prevention

3. Ask Yourself… 1. The body can store fat in virtually unlimited amounts. 2. Dietary cholesterol is found only in animal foods. 3. A person’s blood level of cholesterol is a predictor of that person’s risk of having a heart attack 4. For the health of your heart, the fat you should most avoid eating is cholesterol. 5. The more monounsaturated fats you consume, the better is it for your health. 6. Fruits are essentially fat-free. 7. In general, the softest margarines are the most polyunsaturated. 8. Polyunsaturated fat has the same number of calories as saturated fat. 9. All the foods you eat should contain less than 10% of calories from saturated fat. 10. No one is free of atherosclerosis.

4. Why Do We Need Fats? Dietary fat is one of the most misunderstood concepts in the field of nutrition  What do you know about dietary fats? Functions : provide energy, help to keep us warm, maintain cell membranes, part of various body constituents, provides padding & protection of vital organs

5. Lipids, Fats, and Oils…What’s the Difference? Lipids: organic substances that are relatively insoluble in water and soluble in organic solvents Fats: solid at room temperature  USUALLY solid  Examples? Oils: liquid at room temperature  USUALLY liquid  Examples?

6. Lipids, Fats, and Oils: Dietary Sources Dietary sources of fat  Oil, butter, margarine, and shortening  Meats, bacon, eggs, and nuts  Mayonnaise, salad dressings, and gravy  Cheese, ice cream, and whole milk Can you choose which are “healthy” and which are “unhealthy” fats?

7. A Primer on Fats The functions of fats in the body  Body’s main storage form of excess calories consumed  Primary energy source for body’s work during rest and for light to moderate activity Excess carbohydrate and protein can be converted to fat but not vice versa One pound of body fat supplies 3,500 calories

9. A Primer on Fats The functions of fats in foods  Provide concentrated source of calories  Provide satiety  Carry fat-soluble vitamins (A, D, E, and K)  Carry essential fatty acids  Contribute aroma and flavor FAT?

10. Major Classes of Lipids Lipids are compounds that include:  Triglycerides  Fats and oils  Major dietary source of fats  Phospholipids  Lecithin  Emulsifier and stabilizer  Contain a phosphate group  Sterols  Cholesterol  Fat soluble vitamins  A, D, E, & K

11. A Closer View of Fats Energy-yielding nutrients stored as fat  First broken into small molecules of carbon, hydrogen, and oxygen  These link together as chains (fatty acids), which serve as building blocks for triglycerides

12. Lipid Structures TriglyceridePhospholipid

13. A Closer View of Fats Chain Length and Saturation  Fatty acids differ in chain length and degree of saturation  Chain length: number of carbons, which affects water solubility  Longer chains : stronger, likely solid, stable at higher temperatures, less water soluble  Shorter chains : weaker, likely liquid, less stable at higher temperatures, more water soluble  Degree of saturation: number of hydrogen atoms bonded with the chain

14. A Closer View of Fats Saturated versus unsaturated fats  Saturated fatty acid has the maximum number of hydrogen atoms  Single carbon-carbon bonds  Typically solid at room temp  Unsaturated fatty acid has one of more points without a bonded hydrogen  Double bonds  Monounsaturated fatty acid (MUFA) has one point of unsaturation (“missing” hydrogen)  One double bond  Typically thick liquid or soft solids at room temp  Polyunsaturated fatty acid (PUFA) has two or more points of unsaturation  Two or more double bonds  Typically liquid at room temp

16. A Closer View of Fats Unsaturated Fats  Intake reduces risk of heart disease and cancer  “Mediterranean Diet”  Women who follow this have a considerably reduced risk of breast cancer  Individuals with diabetes have significantly improved blood glucose  When shopping…  Look for foods with LOW amounts of saturated fat and HIGH amounts of mono- and polyunsaturated fats

17. Activity! 1. Write down everything you ate and drank yesterday 2. Write down how much exercise you got yesterday, if any 3. How could you improve your diet/activity habits to reflect the Mediterranean Diet?  Write down what you could improve upon  Example: Order grilled fish instead of fried catfish at a restaurant

20. A Closer View of Fats The essential fatty acids  Fatty acids that must be supplied by the diet because our bodies cannot desaturate before omega-9  Linoleic acid (omega-6)  Linolenic acid (omega-3)

21. A Closer View of Fats Omega-6 versus omega-3 fatty acids  Omega-6 fatty acids: polyunsaturated fatty acids that have their endmost double bonds after the sixth carbon in the chain  Responsible for inflammation, blood clotting, constriction of blood vessels  Omega-3 fatty acids: polyunsaturated fatty acids that have their endmost double bonds after the third carbon in the chain  Responsible for dilation of blood vessels, reduction of inflammation and clotting  Enhance defenses against cancer and reduce inflammation in arthritis and asthma sufferers Arachadonic (n-6) & DHA (n-3):  In infancy: assist with growth, and development of eyes, central nervous system, and brain  Found in breast milk

22. A Closer View of Fats: 3’s and 6’s Omega-3 Food Sources Omega-6 Food Sources Nuts and seeds (walnuts, flaxseeds, chia seeds) Oils: corn, sunflower, safflower, cottonseed, and soybean Flaxseed oilMeat Fatty fishPoultry Fish oilsEggs

23. A Closer View of Fats: 3’s and 6’s …So why are we encouraged to increase our omega-3 (EPA & DHA) intake?  A typical American diet contains 11 – 30 times more n-6 than n-3 fatty acids  We eat so many processed foods and high fat meats  The presence of n-6 fatty acids slows conversion of n-3 fatty acids Why does dietary intake make a difference?  Competitive interactions  Dietary levels affective relative storage, mobilization, conversion, and action  Consuming preformed EPA & DHA is recommended because the accumulation in tissues is more effective when obtained directly from foods  Compounds made from essential fatty acids have an effect on immunity and cardiovascular health

24. A Closer View of Fats: 3’s and 6’s What’s the recommended intake?  Adequate Intakes (AIs):  n-6:  Females: 12 grams/day  Males: 17 grams/day  n-3:  Females: 1.1 grams/day  Males: 1.6 grams/day  Approximate recommended ratio of n-3 to n-6: 1:10 Dietary Guidelines for Americans & AHA Recommends:  Consume 2 servings of fish high in n-3 fatty acids per week  Potential harm for children and pregnant women: mercury content

25. A Closer View of Fats: 3’s and 6’s Essential fatty acid deficiency:  Irritated and flaky skin  GI problems  Compromised immune system  Poor wound healing  Slow growth for children  Physical and mental development impaired My Advice:  Eat more “real” foods….the fewer ingredients on the label, the better!  Cook for yourself so you control what goes in your food  Moderation is key!  Treat yourself occasionally, but don’t over-do it.

26. A Closer View of Fats Saturated Fatty Acids  Recall: no double bonds  Consuming foods high in saturated fat can raise LDL (bad) cholesterol and increase your risk of heart disease  Saturated fats occur naturally in many foods such as high-fat beef, lamb, pork, poultry skin, lard, 2% or whole-fat dairy products, palm and palm kernel oil, and coconut oil  Recommendations:  Dietary Guidelines for Americans:  <7% total kcals from saturated fat  For a 2000-kcal diet, how many grams of saturated fat is this?

27. A Closer View of Fats Saturated Fatty Acids  https://www.youtube.com/watch?t=92&v=OzRARdo09jg https://www.youtube.com/watch?t=92&v=OzRARdo09jg

28. A Closer View of Fats: Cis vs Trans Double bonds can occur as cis or trans in form Most occur as cis : hydrogens at double bond are on the same side, causing a kink in its form  Naturally occurring fatty acids Trans : hydrogens are on opposite sides, allowing the structure to be more linear (similar to saturated fats)  Most trans fats found in our diet comes from processed foods due to hydrogenation  More solid; increases shelf life

30. A Closer View of Fats: Trans Trans fatty acids:  Most blood cholesterol-raising type of fat  Even more than saturated fats  Trans fatty acids and saturated fats increase LDLs and decrease HDLs  Trans fats ↑ risk for heart disease  We have known since ~1970 that trans fats increase risk of heart disease  1999: became a topic of conversation  2005: FDA required labeling of trans fat on food items

32. …So how do I eat less “bad” fats? To cut back on your intake of saturated and trans fats,  Eat a dietary pattern that emphasizes fruits, vegetables, whole grains, low-fat dairy products, poultry, fish and nuts. Also limit red meat and sugary foods and beverages.  Use naturally occurring, unhydrogenated vegetable oils such as canola, safflower, sunflower or olive oil most often.  Look for processed foods made with unhydrogenated oil rather than partially hydrogenated or hydrogenated vegetable oils or saturated fat.  Use soft margarine as a substitute for butter, and choose soft margarines (liquid or tub varieties) over harder stick forms. Look for “0 g trans fat” on the Nutrition Facts label and no hydrogenated oils in the ingredients list.  Doughnuts, cookies, crackers, muffins, pies and cakes are examples of foods that may contain trans fat. Limit how frequently you eat them.  Limit commercially fried foods and baked goods made with shortening or partially hydrogenated vegetable oils. Not only are these foods very high in fat, but that fat is also likely to be trans fat. www.heart.org

34. A Closer View of Fats: Review Characteristics of fats in foods  The more unsaturated a fat, the more liquid it is at room temperature  Solid fats contain saturated fats, cholesterol, and/or trans fats  What are ways to prevent spoilage of oils containing unsaturated fatty acids?  Change the oil chemically by hydrogenation  Add an antioxidant, e.g., BHA or BHT  Refrigerate the product

36. Members of the Lipid Family: Phospholipids and Sterols Phospholipids: phosphorus-containing fats  Have a water-soluble head and fat-soluble tail  Function as an emulsifier  Are an important part of the cell membrane Sterols: large molecules with a multiple-ring structure  Example: cholesterol

40. Digestion of Fats Mouth: lingual lipase Stomach: gastric lipase Pancreas: pancreatic lipase Liver: synthesizes bile Gallbladder: stores and delivers bile Small Intestine: emulsification of fats (bile)

44. Lipoproteins Lipids are not water soluble Lipoproteins = protein + fat Lipoproteins help transport triglycerides & cholesterol in the watery body fluids (blood)  Considered “water-soluble vehicles” for lipids  Outer layer: protein  Hydrophillic  Inner layer: lipid  Hydrophobic

45. Lipoproteins Very low density lipoproteins (VLDL):  Origin: Liver  Made of triglycerides  Function: deliver fatty acids to cells Intermediate density lipoproteins (IDL):  Function: transports fatty acids Low density lipoproteins (LDL):  Function: transports cholesterol to tissues  High amounts in blood = increased risk of heart disease High density lipoproteins (HDL):  Function: brings cholesterol back to the liver to be excreted

47. Cholesterol Cholesterol resembles fat in structure and is needed by the body in order to function properly Cholesterol is produced by the body (mainly in the liver) and is consumed in the diet

48. Cholesterol In the body, cholesterol is used to:  Produce hormones  Absorb vitamin D  Assist in digesting food Our bodies make all of the cholesterol that’s needed to perform these vital functions

49. Types of Cholesterol Cholesterol cannot dissolve in the blood, so lipoproteins allow it to travel throughout the bloodstream in order to be transported to cells  Low-density lipoproteins, LDL-cholesterol  High-density lipoproteins, HDL-cholesterol

50. What is good and bad cholesterol?

52. LDL-Cholesterol LDL-cholesterol makes up roughly 60-70% of total cholesterol It is considered the “bad” cholesterol because:  LDL distributes cholesterol to tissues in the body  This is a vital function because our bodies need cholesterol in order to function properly, but when there is more cholesterol than is needed, it begins to build up in the arteries  This cholesterol build up, referred to as plaque, causes the arteries to narrow and harden

53. LDL-Cholesterol

54. HDL-Cholesterol HDL-cholesterol makes up roughly 20-30% of total cholesterol It is considered the “good” cholesterol because:  HDL removes cholesterol from tissues and brings it to the liver  The liver then removes this cholesterol from the body A low HDL-cholesterol level is a risk factor for heart disease

55. HDL-Cholesterol

56. How the Body Handles Fat “Good” (HDL) versus “bad” (LDL) cholesterol  What are possible causes of high blood cholesterol?  Inherited tendencies  Eating too much saturated fat and trans fat  Exercising too little  Carrying too much weight  Atherosclerosis is the underlying cause of most heart disease

57. How the Body Handles Fat “Good” versus “bad” cholesterol  What are leading risk factors for heart disease?  High LDL blood cholesterol level  Low HDL blood cholesterol level  High blood pressure  Cigarette smoking  Obesity and physical inactivity  Diabetes  An “atherogenic” diet

59. How the Body Handles Fat The trans fatty acid controversy—is butter better?  Trans fatty acid is formed when margarine is processed  Trans fats are man-made products  Trans fats are associated with  Higher “bad” LDL-cholesterol  Lower “good” HDL-cholesterol  Harvard University researchers attribute 30,000 deaths each year to trans fatty acids

61. Do you…Often Sometimes Rarely Trim or drain fat from meats, remove skin from chicken, and eat fish-based meals? 1051 Incorporate sources of healthy fats in your overall eating pattern? 1051 Eat high-fat foods such as bacon, sausage, fried foods several times a week? 1510 Limit whole eggs or egg yolks to seven per week?1051 Read food labels when shopping?1051 Choose low-fat or fat-free dairy?1051 Bake, rather than fry, foods?1051 Maintain a healthy weight (BMI)?1051 “Eat right” and make trade-offs when eating out?1051 Choose doughnuts, croissants, or sweet rolls for breakfast?1510 Choose reduced-fat or fat-free products when available?1051 Routinely add margarine, butter, salad dressing, and sauces to foods? 1510 Balance a high fat dinner by choosing low-fat foods for breakfast & lunch? 1051 Plan physical activity into your schedule most days/week?1051

62. Fat in the Diet Dietary fat is linked to several diseases  Certain types of cancer, heart disease, arthritis, and gallbladder disease Dietary Guidelines recommend  Limit intake of solid fats  Replace them with monounsaturated fat and polyunsaturated fat Olive oil has a good ratio of omega-3 fatty acids to omega-6 fatty acids

63. Sources of Solid Fat in American Diet…

64. Diet and Heart Disease Atherosclerosis  Narrowing of the arteries due to a buildup of cholesterol-containing plaque in the arterial walls  Self-accelerating process  Made worse by hypertension  Predictors include high LDL-cholesterol, low HDL- cholesterol, high blood pressure, smoking, obesity and physical inactivity

65. What is my risk of developing high cholesterol, atherosclerosis, or heart disease?

66. My Risk Different factors can lead to high cholesterol, including:  Non-Modifiable Factors  Family History  Age  Gender  Modifiable Factors  High LDL-cholesterol  Low HDL-cholesterol  High blood pressure  Cigarette smoking  Diabetes  Physical inactivity  Obesity

67. Family Tree Can you think of anyone in your family with high cholesterol? What about anyone with heart disease or anyone who’s had a stroke?

68. Family History The genes responsible for the amount of bad cholesterol (LDL) your body makes and how fast it is removed from your system can be passed down in families  This means that children, too, can have high cholesterol But, keep in mind that even if high cholesterol or heart disease does not run in your family, you can still develop it

69. Age The atherosclerosis process begins early in life

70. Gender Before the age of 50, more men typically have lower good cholesterol (HDL) and higher bad cholesterol (LDL) levels than women After the age of 50, more women typically have lower good cholesterol (HDL) and higher bad cholesterol (LDL) levels than men

71. Gender: Women

72. Estrogen helps raise good cholesterol (HDL)  This could be why premenopausal women are more protected against developing heart disease After menopause, though, good cholesterol tends to decrease while bad cholesterol increases  Hormone therapy is not recommended to replace estrogen in order to lower the risk of developing heart disease, as it has been proven ineffective

73. Dietary Pattern A diet low in fruits, vegetables, whole grains, lean protein, and low fat dairy and high in cholesterol, saturated fats, and trans fats can raise your bad cholesterol (LDL)  Dietary Cholesterol comes only from animal products  Liver, egg yolk, shrimp, whole milk products (butter, cream, cheeses)  Saturated Fat comes mostly from animal products  Fatty meats, chicken with the skin on, whole milk products, lard, coconut oil, palm oil  Trans Fat is man-made  Found in hard margarines and shortenings

74. Weight Status Being overweight or obese tends to:  Increase bad cholesterol (LDL)  Decrease good cholesterol (HDL)  Increase triglycerides  Increase risk of heart disease and stroke  Increase risk of all-cause mortality

76. Diet and Heart Disease Risk Factors OptimalBorderlineHigh Risk Total cholesterol170200 – 239>240 LDL cholesterol<7070 – 159160 – 189 HDL cholesterol>5040 – 49<40 Triglycerides<150150 – 199200 – 499 BMI18.5 – 24.925 – 29.9>30 Blood pressure<120 / <80120 – 139 / 80 – 89 >140 / >90

77. Fat Can Be Healthy Sources of omega-3 fatty acids  Oily coldwater fish: salmon, cod, farmed catfish, lake trout, herring, bluefish, sardines, albacore tuna, mackerel, and shellfish  Plant foods: flaxseed, chia, seed, canola oil, soy products, pecans, and walnuts FDA-approved claim  “…of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease”

78. Choose Fats Sensibly Ways to reduce fats in home-cooked meals  Use nonstick sprays for frying  Try reducing the fat in recipes a little at a time  Sauté vegetables in water, broth, or wine  Prepare broths in advance, refrigerate, and then skim off hardened fat  Prepare lean cuts of meat  Flavor sauces with herbs and spices  Spread jam on bagels or toast in place of butter

79. Fat Can Be Healthy What’s your meal mentality?  Mindset and practices of the Mediterranean region  “Eat slowly, preferably at regular times of the day, and in a pleasant environment”  Diet emphasizes olive oil; daily inclusions of cheese, yogurt, fruits, vegetables, and whole-grains; and minimal red meats and sweets  Physical activity  Social and emotional support  Allotted calories eaten earlier in the day  Other suggestions…  Eat less saturated and trans fats  Consume more complex carbohydrates and fiber

81. Eat Well Be Well: Nourish the Heart Tips for reducing heart disease risk by reducing contributory factors in the diet and increasing intake of protective factors 1.Become a savvy supermarket shopper by reading nutrition labels 2.Keep blood cholesterol at or below the recommended levels 3.Balance energy intake with energy needs

82. Ask Yourself… 1. The body can store fat in virtually unlimited amounts. T 2. Dietary cholesterol is found only in animal foods. T 3. A person’s blood level of cholesterol is a predictor of that person’s risk of having a heart attack. T 4. For the health of your heart, the fat you should most avoid eating is cholesterol. F 5. The more monounsaturated fats you consume, the better is it for your health. F 6. Fruits are essentially fat-free. T 7. In general, the softest margarines are the most polyunsaturated. T 8. Polyunsaturated fat has the same number of calories as saturated fat. T 9. All the foods you eat should contain less than 10% of calories from saturated fat. F 10. No one is free of atherosclerosis. T

83. Any Questions?