Summary  Diet is the collection of food consumed by an individual within a 24 hour period  Food nourishes the body, it contains nutrients that can be essential, nonessential, caloric or non- caloric  Nutrition is the study of how food nourishes and affects body function throughout the day and health over several years  The goal of eating should be to optimally fuel and nourish the body

 It is important to consume a healthy diet in order to promote health and prevent chronic disease  There are many factors affecting food choice Summary

 Carbohydrates are organic compounds classified as either simple or complex  They provide 4 Calories/ gram (except fiber, which is non- caloric)  They are the preferred fuel of the body  Consume 45-65% of Calories from carbs  Found in plant sources, except animal sources of milk & honey  Alcohol is a carb-like drug and provides 7 Calories/ gram Summary

 Protein is made of 20 amino acids categorized as essential & nonessential  Protein is also categorized as complete (high quality) and incomplete (low quality)  Complete: from animal sources  Incomplete: from plant sources  Combining plant proteins so that all the essential amino acids are present is complementation Summary

 The primary function of protein is tissue repair & maintenance  When used for energy, protein provides 4 Calories/ gram  Adults need 0.8 grams/ Kg body weight protein per day. Adults may consume 10-35% of Calories from protein. Summary

Lipids/Fats By Jennifer Turley and Joan Thompson © 2013 Cengage Module 1.4

Presentation Overview 1. Fats/ Lipids 2. Triglycerides 3. Fatty Acids 4. Phospholipids 5. Sterols Categories, Chemistry, Functions & Food Sources of:

Fats/ Lipids Composition: Lipids contain Carbon, Hydrogen & Oxygen  Lipids are organic compounds  Lipids are soluble in fat Categories of Lipids:  Triglycerides  Phospholipids  Sterols

Triglycerides (aka “dietary fats”)  Energy yield: 9 Calories/ gram  These are the only type of lipid that the body can convert to ATP (i.e. produce energy from)  Fats are the most calorically dense energy-producing nutrient

Triglycerides  Caloric density- Refers to the Calories yielded per weight of the substance  Triglycerides provide 9 Calories per gram (protein and carbohydrate  4 Calories/ gram alcohol Alcohol  7 Calories/ gram)

Triglycerides Glycerol + 3 Fatty Acids = a Triglyceride 3 units of water are released

Fatty Acids Dietary fats are defined by the composition of the fatty acids in the triglyceride 1. Saturated fatty acids (SFA)  no double bonds 2. Monounsaturated fatty acids (MUFA)  1 double bond 3. Polyunsaturated fatty acids (PUFA)  2 (or more) double bonds

Fatty Acids Stearic Acid Oleic Acid Alpha-linolenic acid

Fatty Acids Saturated Fatty Acids  found in animal products, hydrogenated vegetable fats, tropical oils (palm & coconut)  Solid at room temperature  More unhealthy than MUFA or PUFA Chemistry of Stearic Acid, a SFA

Fatty Acids Monounsaturated Fatty Acids  Primarily found in olive and canola oil, almonds & avocado  Liquid at room temperature  Healthier than SFA Chemistry of Oleic Acid, a MUFA

Fatty Acids Polyunsaturated Fatty Acids  Found in corn, cottonseed, safflower & sunflower oil  Liquid at room temperature  Healthier than SFA Chemistry of Alpha-Linolenic Acid, a PUFA

Essential Fatty Acids  Linoleic & alpha-linolenic acid  The body cannot make them, must get from diet  Found in plant oils and foods  Can develop deficiency symptoms/ characteristics if these are lacking in the diet

Essential Fatty Acids  Linoleic & alpha-linolenic acid  The AMDR levels for adults that will optimize health are:  5-10% of Calories from Linoleic Acid  % of Calories from Alpha-linolenic Acid  Linoleic Acid is an omega 6 fatty acid.  Alpha-linolenic Acid is an omega 3 fatty acid.

Trans Fatty Acids  Created in food processing when MUFAs and PUFAs are partially hydrogenated

Functions of Fats  Increases satiety value of a meal  Improves texture, flavor & aroma of food  Required for fat soluble vitamin absorption  Provides the body’s major energy stores  Cushions vital organs  Is an essential structural component of cell membranes  Provides insulation

Dietary Recommendations for Fats  AMDR: <7% should come from SFA. Limit trans fatty acids  All excess Calories consumed whether from carbohydrates, proteins, or fats are converted to fat & stored in fat cells  Fat is the storage form of energy in mammals

Phospholipids (lecithin)  Non-Energy Yield: 0 Calories per gram. Phospholipids are non-caloric lipid substances.  Sources: Lecithin is found in egg yolk and soy products and is the most common phospholipid consumed in the diet

Phospholipids (lecithin)  Functions 1. An emulsifier, which allows water soluble & fat soluble substances to mix (example: oil + vinegar) 2. Lecithin provides choline, which is a component of the neurochemical acetylcholine 3. Used to make cell membranes

Phospholipids (lecithin)

Phospholipids Includes 1) phospholipids, 2) cholesterol & 3) proteins In cell membranes: 12 3

Sterols Cholesterol is the most abundant dietary sterol  Non-Energy Yield= Non-caloric (0 Calories/gram)  Sources of Cholesterol 1. Exogenous: Get from diet. Cholesterol is made by animals  only found in animal foods & their by-products 2. Endogenous: Made inside the human body

Sterols Exogenous Sources:  Egg yolk provides ~275 mg each  Organ meats & crustaceans such as crab, shrimp & lobster provide ~190 mg per 3 ounces  Much smaller amounts are in the fat portions of animal meats & products like milk

Sterols Endogenous Sources:  Cholesterol is made inside the human body, primarily in the liver, from SFA  Usually about 1 gram (1,000 milligrams) of cholesterol per day is produced in the body

Functions of Cholesterol & cell membranes!

Dietary Recommendations for Cholesterol  Cholesterol can be deposited in the artery walls leading to plaque buildup & heart disease  To maintain heart health, the dietary recommendation is to limit intake to <300 mg/day  To improve heart health, limit intake to <200mg/day.

Summary  Fats/Lipids are organic compounds  Fats/Lipids are categorized as triglycerides, phospholipids, and sterols  Triglycerides provide 9 Calories/ gram  Triglycerides contain fatty acids that are categorized as SFA, MUFA, & PUFA  There are 2 EFAs  Triglycerides have many important functions

Summary  Consume 20-35% of Calories from fat & limit SFA to <7% of Calories  Phospholipids like lecithin, emulsify and help make up cell membranes and acetylcholine  Cholesterol is found in animal foods. It is not essential and can be made in the liver. It has many important functions in the body but intake should be limited to less than 300 mg/day. References for this presentation are the same as those for this topic found in module 1 of the textbook