Triglycerides Phospholipids Sterols The Lipids Triglycerides Phospholipids Sterols

Triglycerides Phospholipids Sterols The Lipids Triglycerides Phospholipids Sterols

Bacon Everywhere? http://centernjlife.blogspot.com/2009/02/bobby-jindal-and-baconaise-through-eyes.html I’m not trying to be political, watch starting at 2:20 (till 3:45) for a profound “are you kidding me” moment on the state of nutrition in America.

Macronutrients: Our Main Questions What are they? What do they do in us? Where do they come from? Structure Digestion Metabolism and Storage Recommended Allowances Consequences of too much Consequences of too little Other Issues (substitutes, etc.)

Lipids: What are They?

Lipids: What are They? Saturated fat Unsaturated fat Polyunsaturated fat Monounsaturated fat But also, Cell membranes Myelination Cell signaling

Lipids: What do they do? Lipids in foods and in the human body fall into three classes Triglycerides ≈95% of all lipids in foods and the human body Phospholipids For example, lecithin Form the “walls of your cells” Sterols For example, cholesterol Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

Lipids: What do they do? Fat is the body’s major storage form of energy Fats pack tightly together without water Relative to carbohydrate, much more fat can be stored in a small space Gram for gram, fats provide more than 2x the energy of carbohydrate Making fat an efficient storage form of energy

Lipids: What do they do?

Lipids: What do they do?

Lipids: What do they do?

Lipids: Where do they come from?

Structure: Fatty Acids and Triglycerides Glycerol

Structure: Fatty Acids and Triglycerides glycerol + 3 fatty acids  triglyceride + H2O

Structure: Fatty Acids Length Saturated vs. unsaturated Point of saturation

Structure: Fatty Acid Length Stearic acid – 18-carbon, saturated

Structure: Fatty Acid Saturation Degree of saturation (how many) Saturated (0) fatty acid Monounsaturated (>1) fatty acid Polyunsaturated (>1) fatty acid

Structure: Fatty Acid Saturation Degree of saturation (how many) Saturated (0) fatty acid Monounsaturated (>1) fatty acid Polyunsaturated (>1) fatty acid

Structure: Fatty Acid Saturation Degree of saturation (how many) Saturated (0) fatty acid Monounsaturated (=1) fatty acid Polyunsaturated (>1) fatty acid

Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated Fats are like toothpicks, the straighter they are, the tighter you can pack them (and make them solid)

Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated Degree of saturation Affects the temperature at which the fat melts In general, the more unsaturated the fatty acids, the more liquid the fat is at room temperature In general, the more saturated the fatty acids, the firmer the fat is at room temperature

Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated Degree of saturation

Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated To determine if an oil you use contains saturated fats Place the oil in the refrigerator and watch for cloudiness Because it is solidifying The least saturated oils remain the clearest

Structure: Point of Saturation Location of double bonds Omega number Omega-3 fatty acid Omega-6 fatty acid How does the body use each differently?

There is more to it, if you’d like to look. http://www.time.com/time/magazine/article/0,9171,993419,00.html

Fish Oil and Heart Disease http://www.nytimes.com/2006/10/03/health/03fish.html

There is more to it, if you’d like to look.

Structure: Degree of Saturation and Spoilage Degree of unsaturation revisited Firmness Stability Oxygen breaks down carbon bonds and makes food rancid.

Structure: Degree of Saturation and Spoilage Rancid Fresh Oxygen breaks down carbon bonds and makes food rancid. Unsaturated fats are most stable. Polyunsaturated fats spoil more rapidly.

http://www.youtube.com/watch?v=4izMF8MXNgU

Triglycerides The food industry has come up with two solutions. Hydrogenation Turn unsaturated fats to saturated fats. It makes them more solid in your blood vessels. Trans fats. Reorient the double bonds to make them less susceptible to oxygen.

Triglycerides The food industry has come up with two solutions.

Hydrogenation

Cis- and Trans-Fatty Acids Compared

Where are Trans Fats: Partially Hydrogenated

Transition

Lipids: What are They Lipids in foods and in the human body fall into three classes Triglycerides ≈95% of all lipids in foods and the human body Phospholipids For example, lecithin Form the “walls of your cells” Sterols For example, cholesterol Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

Phospholipids

Phospholipids Phospholipids = 2 fatty acids + glycerol + a phosphorus-containing molecule Fatty acid is soluble in fat Phosphorus is soluble in water Phospholipids are emulsifiers A substance that mixes with both fat and water and permanently disperses the fat in the water Forming an emulsion

Phospholipids

Phospholipids

Cholesterol Strengthens Cell Membranes:

Cholesterol Strengthens Cell Membranes: But keep it in check

Lipids: What are They Lipids in foods and in the human body fall into three classes Triglycerides ≈95% of all lipids in foods and the human body Phospholipids For example, lecithin Form the “walls of your cells” Sterols For example, cholesterol Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

Sterols Large, complicated molecules consisting of interconnected rings of carbon atoms with side chains of carbon, hydrogen, and oxygen

Sterols The sterol cholesterol serves as the precursor for making bile Component of cell membranes Can be made by the body Not an essential nutrient Forms the major parts of the plaques that narrow arteries in atherosclerosis Vitamin D and sex hormones are also sterols

Sterols The sterol cholesterol serves as the precursor for making bile Component of cell membranes Can be made by the body Not an essential nutrient Forms the major parts of the plaques that narrow arteries in atherosclerosis Vitamin D and sex hormones are also sterols

transition

Fat DigestionOverview

Fat Digestion Small intestine Bile Produced by the liver Stored in the gallbladder Secreted in the small intestine Emulsifies fat

Fat Digestion

Lipid Transport

Lipid Transport Lipoproteins Chylomicrons VLDL = very-low-density lipoproteins LDL = low-density lipoproteins HDL = high-density lipoproteins

Lipid Transport Lipoproteins and health LDL vs. HDL

1. Fats are absorbed from the intestine as VLDL

As fats move through the blood stream, they drop off lipids.

3. As they do, they carry less lipid (making them higher in density) VLDL →LDL→HDL

4. If there is already lots of fat in the blood vessel, fat is not dropped off.

5. Fat gets dumped off anyway and sticks to the vessel wall, clogging arteries.

Lipoproteins and Heart Disease Risk →HDL The LDL and HDL difference LDL Larger, lighter, and richer in cholesterol than HDL Deliver triglycerides and cholesterol from the liver to tissues HDL Smaller, denser, and packaged in more protein than LDL Scavenge excess cholesterol and phospholipids from tissues for disposal ←LDL

Lipoproteins and Heart Disease Risk Elevated LDL concentrations in the blood are an indication of heart attack risk Why? Elevated HDL concentrations in the blood are associated with a low heart attack risk The difference is attributable to the proportions of lipids they contain and the tasks they perform The difference is not in the type of cholesterol they carry →HDL ←LDL

Lipoproteins and Heart Disease Risk Risk factors that cannot be changed Increasing age Being male Family history of premature heart disease

Lipoproteins and Heart Disease Risk Risk factors that a person can often control High blood LDL; low blood HDL High blood pressure Diabetes Obesity Physical inactivity Cigarette smoking Atherogenic diet Get more fiber

Wouldn’t It Be Nice To Have a List of Foods High in HDL and LDL Well, its not in your book, so we will have to make that list ourselves. 10 points. Find 5 foods high in HDL Find 5 foods high in LDL Submit it to me (handwritten is fine) I will assemble the list for us.

Translation: More fiber = less bile Less bile = less fat absorption

High-Fat Foods Seven Countries Study of healthy people Death rates from heart disease were strongly associated with diets high in saturated fats Death rates from heart disease were only weakly associated with diets high in total fat Finland & the Greek island of Crete were the two countries with the highest fat intake Finland had the highest rate of death from heart disease Crete had the lowest rte of death from heart disease

High-Fat Foods Finland vs. Crete Both consume 40+% of calories from fat Thus, total fat was not the culprit in heart disease Relative to Finland people in Crete had a diet High in olive oil Low in saturated fat Less than 10% of calories After an average follow-up of 46 months (almost four years), patients following the Mediterranean-style diet had a 50–70 percent lower risk of recurrent heart disease.

High-Fat Foods People naturally like high-fat foods As fat becomes less expensive and more available in a given food supply, people seem to choose diets providing greatly increased amounts of fat Fats carry many dissolved compounds that give foods enticing aroma and flavors Fat also lends a tenderness to foods such as meats and baked goods

Recommended Intakes of Fat DRI: 20% - 35% of energy intake Or, pick who you trust… DRI WHO AHA

Cutting Fat Cuts kCalories and Saturated Fat

High-Fat Foods Cook with olive oil Nibble on nuts Feast on fish But beware of mercury

High-Fat Foods Limit fatty meats, milk products, and tropical oils

High-Fat Foods Limit hydrogenated foods

Other Issues: Fat Substitutes Fat replacers Artificial fats Olestra

Olestra Fat replacers Artificial fats Olestra

High-Fat Foods Changing guidelines for fat intake