ENERGY NUTRIENTS: THE BIG PICTURE WHY WE EAT FUNCTIONS FATS FAT, CARBS, PROTEIN

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1 ENERGY NUTRIENTS: FAT, CARBS, PROTEIN Angeline B. David, DRPH, MHS NAD Health Summit March 14, 2013 The science of cooking is not a small matter.... This art should be regarded as the most valuable of all the arts, because it is so closely connected with life. It should receive more attention; for in order to make good blood, the system requires good food. The foundation of that which keeps people in health is the medical missionary work of good cooking. {CG 372.1} Often health reform is made health deform by the unpalatable preparation of food. The lack of knowledge regarding healthful cookery must be remedied before health reform is a success. {CG 372.2} THE BIG PICTURE Foods are composed of: Fats Carbohydrates Proteins Vitamins Minerals Water Other compounds WHY WE EAT Energy (kilo/calories) to function Only 3 nutrients in food give energy (macronutrients) Fats! 1 gram! 9 calories Carbohydrates! 1 gram! 4 calories Proteins! 1 gram! 4 calories (alcohol)! 1 gram! 7 calories Other components are also important! FATS FUNCTIONS Provide 35-40% of calories in diet Support cell-to-cell communication Form structure of cell walls Provide insulation Serve as precursors (eg, hormones) Act as transporters

2 Decreased growth rate Skin and hair problems Inflammation Infertility DEFICIENCIES Kidney & liver abnormalities Fragile red blood cells Poor wound healing And more... BASIC INFO Cannot be dissolved in water Type of fat consumed is key Triglycerides and fatty acids Sterols: cholesterol (animal), phytosterol (plant) Lipoproteins transport fat: HDL, LDL Classified by number of double bonds Saturated! 0 double bonds Monounsaturated! 1 double bond Polyunsaturated! 2+ double bonds - Trans-fatty acids! 1 double bond removed (partially hydrogenated) FATTY ACID CLASSIFICATION FOOD SOURCES ESSENTIAL FATTY ACIDS Must be eaten because body cannot make these Only 2 are essential linoleic acid (n-6 or omega-6) alpha-linolenic acid (n-3 or omega-3) - Converted to EPA and DHA - Decrease triglyceride levels in blood Incorporated into most all cell membranes Compete with saturated fats! fluid membranes Play role in platelet aggregation, smooth muscle constriction, inflammatory response, cell growth, clot formation, asthmatic & allergic response Needed for brain development (perinatal, adolescence) and supports brain functions

3 ESSENTIAL FATTY ACID FOOD SOURCES Linoleic acid (essential omega-6) Eggs, poultry, cereals, vegetable oils, whole-grain breads, baked foods, margarine, breast milk Alpha-linolenic acid (essential omega-3) Canola oil, flax and flaxseed oil, walnuts, chia seeds leafy green vegetables, fatty fish, breast milk EPA (n-3) Fatty fish, fish oil, breast milk DHA (n-3) Algae oil, fatty fish, fish oil CHOLESTEROL Waxy substance Produced in liver of animals & humans Transported to & from tissues via lipoproteins Only dietary source is from animal foods (meat, eggs, dairy) Excess! plaque buildup in arteries! heart attack or stroke LIPOPROTEINS BLOOD LEVELS Transport molecules for lipids Produced mostly in liver HDL (high density lipoproteins) happy - high levels decrease risk of heart disease Clears cholesterol from tissues Increase with exercise & stop smoking LDL (low density lipoproteins) lousy - high levels increase risk of heart disease Carries fats from liver to tissues then becomes concentrated with cholesterol Lower by decreasing trans-fats & increasing omega-3 fats HDL happy LDL lousy Triglycerides Total cholesterol Optimal > 60 High risk < 40 (M) < 50 (F) Optimal < 100 High risk > 160 Normal < 150 High risk > 200 Optimal < 200 High risk > 240 Units in mg/dl FAT RECOMMENDATIONS CARBOHYDRATES Reduce saturated and trans-fat intake Substitute cholesterol with monounsaturated fats (eg, olive oil) Increase omega-3 fats

FUNCTIONS Provide about 50% of calories in diet Form structure of organs and cells Facilitates cell-to-cell communication Support gastrointestinal health (fiber) Provide sweetness in foods BASIC INFO

humans as glycogen in liver and muscles GOOD & BAD Complex Carbs Simple Carbs Class Starch & Fiber Sugars Digestion Effect on Blood Sugar Other Effects Food Sources Starch: slow Fiber: not digested

4 FUNCTIONS Provide about 50% of calories in diet Form structure of organs and cells Facilitates cell-to-cell communication Support gastrointestinal health (fiber) Provide sweetness in foods BASIC INFO Large family of naturally occurring compounds; few have dietary importance Stored in plants as: starches fiber: soluble and insoluble sugars: glucose, fructose, galactose, etc Stored in animals & humans as glycogen in liver and muscles GOOD & BAD Complex Carbs Simple Carbs Class Starch & Fiber Sugars Digestion Effect on Blood Sugar Other Effects Food Sources Starch: slow Fiber: not digested Stable Sustained energy & longer satiety Whole grains, beans, fruits, vegetables Quick Wide swings Increase risk of diabetes & obesity Refined sugars, grains, flours, etc DIGESTION & ABSORPTION Begins in the mouth via enzymes in saliva Broken down into smallest chemical form in the stomach and intestine Absorbed into bloodstream inside the small intestine Fiber is not absorbed Pancreas secretes insulin Transported to the liver or muscles for storage Excess is converted to fat GLUCOSE Primary source of energy for most cells Glucose transporter needed to take glucose into cells Some need insulin Main goals of glucose regulation Glucose balance in blood Provide sufficient glucose for brain function INSULIN Hormone made by cells in pancreas in response to glucose in bloodstream Helps to activate other cells for glucose transport Diabetes is excess glucose in the blood Type I diabetes: pancreas cells cannot produce insulin Type II diabetes: pancreas cannot produce enough insulin

5 DIETARY FIBER Found in plant foods Cannot be digested by humans 2 types: soluble and insoluble Type of fiber in foods are different, but in general: Fruits & vegetables have mostly soluble Grains & legumes have mostly insoluble HEALTH EFFECTS OF FIBER Modifies blood glucose levels after eating Lowers blood cholesterol levels Improves bowel function Assists in weight loss Possibly reduces risk of colon & breast cancer Overconsumption can lead to bloating, flatulence, binding of vitamins & minerals FOOD SOURCES OF FIBER Soluble fiber oats nuts & seeds legumes & beans apples & berries Insoluble fiber wheat, whole grains, brown rice, barley wheat bran carrots, celery, zucchini CARBOHYDRATE RECOMMENDATIONS 3 to 5 servings of fruits & vegetables per day 6 servings of whole grains & legumes per day 130 grams total carbs per day grams of fiber per day grams of soluble fiber Increase water intake Variety is the spice of life! PROTEIN FUNCTIONS Provide 10-35% of calories in diet Major structural component of all cells Act as enzymes and hormones Incorporated into membranes Transport molecules throughout body Precursors to other important molecules (nucleic acids, hormones, vitamins, etc)

BASIC INFO Nitrogen composes 16% of weight of proteins Amino acids are the building blocks of proteins 100 amino acids found in nature 20 can be used by humans AMINO ACIDS For nutrition: amino acid

premature infants, illness 5 are dispensable PROTEIN QUALITY Proteins differ in their ability to support growth Depends on availability and digestibility of amino acids in the protein Complete

6 BASIC INFO Nitrogen composes 16% of weight of proteins Amino acids are the building blocks of proteins 100 amino acids found in nature 20 can be used by humans AMINO ACIDS For nutrition: amino acid composition of protein is paramount Classification 9 are indispensable/essential - cannot be made by body 6 are conditionally indispensable - cannot be made sufficiently under some conditions, eg premature infants, illness 5 are dispensable PROTEIN QUALITY Proteins differ in their ability to support growth Depends on availability and digestibility of amino acids in the protein Complete protein - contains essential amino acids in adequate amount & proportion to support growth Meat, milk, egg, soy Incomplete protein - low in one or more essential amino acid; may sustain life but do not support growth Beans, peas, nuts, grains PROTEIN QUALITY Each protein food contains multiple amino acids Limiting amino acid - essential amino acid that is in the lowest proportion in the protein food Each food may have a different limiting amino acid Complementary proteins - 2 or more incomplete proteins yield a complete protein when combined eg, beans and rice PLANT-BASED PROTEINS

7 TRUE & FALSE Young & Pellett, 1994 Young & Pellett, 1994 High Fat Food Calories Grams Protein % Calories from protein Pinto beans, cooked, ~! cup Lentils, cooked, ~! cup Tofu, firm, ~! cup Brown rice, cooked, ~! cup White rice, cooked, ~! cup Whole wheat bread, 3 slices, ~! cup Oatmeal, cooked, ~! cup Potato, cooked without skin, ~! cup T-bone steak, ~ 3 oz Hamburger patty, ~ 3 oz Roasted chicken, white meat, ~ 3 oz Broccoli, cooked, ~ " cup Spinach, cooked, ~! cup Mushrooms, cooked, ~! cup PROTEIN RECOMMENDATIONS 0.8 grams of protein per kg of body weight 150 lbs 2.2 = 68 kg x 0.8 = 54.4 g pro Well-planned plant-based diet provides sufficient protein to support health Variety is the spice of life! angberda@gmail.com

Laura Kim, MGH Dietetic Intern March 17, 2015

Laura Kim, MGH Dietetic Intern March 17, 2015 Introduction Carbohydrates Fats Proteins Understand basic functions of each nutrient Identify food sources of carbohydrates, fats, proteins Create balanced