NURT 202 1nd Edition Lecture 10 Ch5 continued Lipid Digestion and Absorption goal is to convert triglycerides into fatty acids Body composed primarily of water and the gastrointestinal tract is mostly an aqueous environment Lipids are hydrophobic The digestion and absorption of lipids requires Bile Micelles Chylomicrons Mouth Minor digestion i e milk Lingual lipase Remove some fatty acids Stomach Additional digestion Gastric lipase Remove some fatty acids Small Intestine Phase 1 Micelle Formation Gallbladder releases bile into the SI Bile emulsifies large fat globules into smaller particles Micelles These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Phase 2 Digestion of Triglycerides Release of pancreatic lipase Triglycerides in the small micelles are digested by the pancreatic lipases In the Small Intestine Micelles diffuse into the intestinal mucosal cells Inside the mucosa cells Fatty acids are reassembly into triglycerides And Packed into lipids transport particles Lipoproteins Chylomicrons Chylomicrons enter the lymph Lipoproteins transport lipid compounds throughout the body Fatty acids cholesterol and other fat soluble vitamins Lipoproteins transport fat soluble nutrients from diet throughout the body The outer layer is composed of cholesterol phospholipids proteins Chylomicron Very low density lipoprotein VLDL From small intestine Dietary fats triglyc From liver Mainly triglycerides Low density lipoprotein LDL From liver bad cholesterol High density lipoprotein HDL From liver good cholesterol 1 Chylomicrons Location Made in the small intestine Size Largest and least dense Composition Mostly dietary triglycerides Function Carry digested fat from small intestine through lymph into bloodstream to cells to deliver triglycerides to cells 2 Very low density lipoproteins VLDL Similar to Chylomicrons but Location Made in the liver Size 2nd largest and 2nd least dense Composition Mostly triglycerides Function Deliver fat made in liver to cells 3 Low density lipoproteins LDL lethal Location Made in the liver Composition Mostly cholesterol Function Deliver cholesterol to cells Bad cholesterol High levels associated with heart disease 4 High density lipoproteins HDL heart healthy Location Made in the liver Size Most dense smallest Composition Mostly protein Function Remove cholesterol from cells tissues deliver to liver for recycling excretion Good cholesterol High levels associated with heart health Most lipids in the body are triglycerides stored in adipose tissue Cholesterol is used to make several hormones including estrogen testosterone Triglycerides are broken down to fatty acids and glycerol Fatty acids and glycerol used to produce ATP ATP energy 9 calories per gram fat for immediate energy Store fat in adipose tissue for energy later 50 000 calories in form of TGs in a lean man Carbohydrate storage limited Fat storage limitless OR Inadequate intake of essential fatty acids Omega 6 Omega 3 may result in Essential Fatty Acid deficiency Ratio of intake of W 3 to W 6 is important Americans generally consume too much w 6 compared to w 3 Increasing the intake of w 3 relative to w 6 Reduces blood clotting Reduces inflammation Lowers blood pressure Reduced risk of heart disease Heart Diseases Over 70 million Americans suffer from some form of cardiovascular disease CVD Studies show that diet and lifestyle affect the risk of developing cardiovascular disease heart disease Atherosclerosis Type of CVD Accumulation of lipids or fatty fibrous materials or plaques deposit in artery walls Poor elasticity reduced or blocked blood flow In BIG vessels e g aorta iliac coronary To prevent Heart Disease Replace saturated fats with unsaturated fats Regular consumption of omega 3 fatty acids Suppress inflammation Include fish in your Weekly Choices Eat Plenty of Plant Foods Rich in Fiber Rich in Phytochemicals Rich in Antioxidants Plenty Exercise and Weight Management Follow heart healthy dietary patterns Mediterranean diet Asian diet Limit intake of cholesterol trans fat and saturated fat Use low fat dairy Trim the fat from your meat and serve chicken fish don t eat the skin Cut your butter in half use soft rather than stick margarine Use beans instead of meat in your chili soups casseroles Increase the proportion of polyunsaturated and monounsaturated fats Use olive peanut or canola oil for cooking and salad dressing Use corn sunflower or safflower oil for baking Snack on nuts and seeds Add olives and avocados to your salads Increase intake of Omega 3 fats Bake flaxseeds into breads sprinkle on cereal or yogurt Add another serving of fatty fish e g mackerel lake trout herring sardines tuna or salmon Have a leafy green vegetable with dinner Add walnuts to salad or cereal