Lecture Notes-7
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•          Nutrition and Health-Introduction

•          You choose when, what, and how much to eat about 1000 times per year

•          Good nutrition contributes to a long and healthy life

•          Challenging: fighting evolution in modern times

•          Eat a VARIETY of foods in MODERATION

•          Good Web Sites for Nutrition

•          www.nutrition.gov

•          www.eatright.org

•          www.mypyramid.gov

•          www.fruitsandveggiesmorematters.org

•          www.americanheart.com

•          www.cancer.gov

•          www.cancer.org

•          www.foodallergy.org

•          www.ific.org

•          www.foodsafety.gov

•          www.win.niddk.nih.gov

•          www.webmd.com

•          www.www.vrg.org

•          www.nof.org

•          www.nationaldairycouncil.org

•          Nutrition and Health-Introduction

•          What prompts you to eat?

1.       Hunger: the physiological need to eat. Unpleasant sensation.

2.       Appetite: the psychological need to eat. May arise in response to the thought, sight or smell of food even when you do not physically need to eat.

•          Reasons for choosing specific foods:

1.       Personal preferences

•          You like them; they taste good

2.       Habit or ethnic tradition

•          Familiar; you always eat them

3.       Social pressure

•          Offered; feel you can’t refuse

4.       Availability

•          There and ready to eat

5.       Convenience

•          Too rushed or tired to prepare anything else

6.       Economy

•          Affordability

7.       Emotional needs

•          Gratification; makes you feel better for a while

8.       Values or beliefs

•          Religious tradition; environment; social; ethical, etc.

9.       Nutritional value

•          They are good for you (nutrients & energy balance)

      •          Nutrition: the study of nutrients and their effects on the body

•          Nutrients: substances obtained from foods and used in the body for growth, maintenance and repair

•          Essential Nutrients: those nutrients the body cannot make for itself and, therefore, must be obtained in the diet

•          Dietary Guidelines for Americans 2005

•          The deficiency diseases of the past (scurvy, rickets) have been replaced by poor nutrition and inactive lifestyles

•          Undernutrition: inadequate food intake causing disease or susceptibility to disease

•          Example: iron-deficiency anemia

•          Overnutrition (overeating): overconsuming food sufficiently to cause disease or susceptibility to disease

•          Example: obesity

•          Poor nutrition and inactivity (first seven) may cause:

•          Heart disease

•          Stroke

•          Hypertension

•          Dyslipidemia (elevated blood fats)

•          Type II diabetes

•          Overweight & obesity

•          Osteoporosis

•          Constipation

•          Diverticular disease

•          Iron deficiency anemia

•          Malnutrition

•          Some cancers

•          Low intake of foods and nutrients in U.S. population:

•          93% don’t get recommended amount of vitamin E

•          Women consume only a little over half the recommended amount of calcium

•          44% don’t get enough vitamin A

•          33% fall short on vitamin C

•          Iron deficiency-most common trace mineral deficiency

•          Men and women 10 grams/day short on fiber

•          54% not enough vitamin B6

•          33% not enough folic acid (B9)

•          63% not enough magnesium

•          75% not enough zinc

•          The Six Basic Nutrients:

•          Macronutrients (energy nutrients/calories):

•          Protein

•          Fat

•          Carbohydrate

•          Micronutrients

•          Vitamins

•          Minerals

•          Water

•          Protein

•          Recommended intake

•          ~15% of calories (10-35% range)

•          0.36 grams per pound body weight (54 gm - 150lb.; 72 gm – 200 lb.)

•          Energy-yielding (4 calories per gram)

•          Mostly during very long-term exercise or starvation

•          Tissues (muscle, bones, cartilage, skin)

•          Enzymes

•          Hormones

•          Antibodies

•          Made up of amino acids (C-H-O-N)

•          20 AAs

•          11 body can manufacture

•          9 essential

•          All AAs must be available at one time for the body to use protein for tissue building

•          The body cannot make partial proteins—only complete ones

                  Complete Proteins:

•          Contain all of the essential AAs

•          High-Quality Proteins:

•          Contains all essential AAs in proportion to need

•          Incomplete Proteins:

•          Does not contain all essential AAs in proportion to the body’s needs

•          The body cannot make partial proteins—only complete ones—vegans must combine proteins (“protein complementing”)  

•          Sources of Protein:

•          Animal sources of complete, high-quality proteins

•          Meat, fish, poultry, eggs, fish, cheese

•          Legumes (seed pods that split on two sides when ripe)

•          Dried beans, dried peas, dried lentils, peanuts, *soybeans, and *soy products

•          Grains

•          Oats, rice, barley, cornmeal, whole-grain breads and pastas

•          Nuts & Seeds

•          Walnuts, cashews, pecans, sunflower seeds, sesame seeds

•          Vegetables

•          Broccoli and dark, leafy green vegetables

*contains all essential AAs and add’l health benefits

•          Excess protein intake can cause:

•          Calcium excretion

•          Extra nitrogen excreted in the urine, straining kidneys

•          Carbohydrate

•          Carbohydrates include:

•          Simple Carbohydrates (sugars)

•          Complex Carbohydrates (starches; fiber)

•          Recommended Intake:

•           ~45-65% of diet should be carbohydrate

•          No more than 10-25% from simple sugars

•          The body’s most efficient source of energy

•          4 calories per gram

•          Preferred during high-intensity activities

•          Carbohydrates should be the primary source of energy because they are a major source of vitamins, minerals, fiber, and other nutrients good for health.                 

•          Most carbohydrates are plant based:

–        Grains, vegetables, fruits, legumes

•          Simple Carbohydrates (sugars):

–        Monosaccharides

•          Glucose (the body’s fuel)

•          Fructose (fruit sugar)

•          Galactose

–        Disaccharides

•          Sucrose (table sugar)

•          Lactose (milk sugar)

•          Maltose

–        All carbohydrates are broken down in the intestine and converted to glucose in the liver

–        Carbohydrates

•          Complex Carbohydrates:

–        Long chains of glucose units

–        Keep blood sugar level stable and help prevent heart disease, some forms of cancer, and other degenerative diseases

–        Starch: principal carbohydrate found in plants and vegetables

•          Grains, potatoes, fruits, vegetables, legumes

•          Most are nutritionally “dense”

•          Stored in muscles and liver in limited amounts

–        Glycogen: form of carbohydrate found in animals and humans (chains of glucose units)

•          Liver

•          Muscle

–        Carbohydrates

•          Fiber:

–        Mostly indigestible by humans-no calories

–        Holds water – provides intestinal bulk

–        Prevents infection of the appendix, helps control blood-cholesterol levels, reduces heart disease, diabetes, cancer and obesity risk

–        Makes stools softer—preventing constipation and other ills

–        Sources: plant foods, especially with their skins intact

•          Substitute with brown rice, whole wheat products, 100% bran breakfast cereals, whole grain pasta, beans, unpeeled fruits and vegetables

–        Recommendation: 30 gms of fiber per day (typical =15 gms)

•          Carbohydrates

•          Sugar Substitutes:

–        Sugar alcohols

•          Maltilol, sorbitol, xylitol, mannitol

•          Bacteria do not metabolize as easily—do not contribute to tooth decay

•          As many calories as sucrose, even if says sugar free

–        Artificial Sweeteners

•          Calorie-free—no calories

•          Saccharine (warning labels), aspartame

•          Fats

•          No more than 30% of calories should come from fat (with no more than 10% saturated/trans fats)

•          Present in triglyceride form

–        Glycerol—FA—FA—FA    Lypolysis    Glycerol   FFA   FFA   FFA  

•          Essential functions:

–        Concentrated energy source – 9 calories per gram

–        Transport fat-soluble vitamins

–        Insulate & protect body organs

–        Regulate hormones

–        Contribute to growth

–        Part of cell wall, nerve tissue

–        Important for healthy skin

–        Texture and flavor to foods

–        Provide satiety (feeling of fullness)

•          Too much fat can be harmful:

–        Obesity                               

–        High blood pressure

–        Stroke

–        Heart disease

–        Diabetes

–        Some forms of cancer

•          Types of Fats:

–        Saturated

–        Monounsaturated

–        Polyunsaturated

–        Plus:

–        Trans Fats

–        Cholesterol

•          Saturated Fat

•          Solid at room temperature

•          Raises level of LDL cholesterol and linked to heart disease and other degenerative diseases

•          Animal products (meat), butter, lard

–        Monounsaturated Fat

•          Liquid at room temperature

•          Peanuts, cashews, olives, avocados, olive oil, peanut oil, cottonseed oil, canola oil

•          Polyunsaturated Fat

–        Liquid at room temperature

–        Found in most vegetable oils, fish, margarine, walnuts, almonds, pecans, corn oil, sunflower oil, sesame oil, soybean oil

•          Fats

•          Trans Fats

–        Some monounsaturated fats and polyunsaturated fats can undergo hydrogenation during manufacturing, creating trans fats

–        Longer shelf life

–        Found in shortening, margarine, some crackers, and some nut butters

–        May carry as much risk as eating saturated fat

•          Cholesterol:

–        A type of fat

–        Some beneficial roles: digestion, membranes protecting nerve fibers, vitamin D, sex hormones

–        Too much in bloodstream – high risk of developing heart disease

–        High fat diet causes increased cholesterol (just as important as cholesterol intake)

•          Vitamins:

–        Zero calories

–        Organic

–        Smaller quantities

–        Powerful nutrients…deficiencies can be deadly

•          Cure diseases caused by deficiencies in the vitamin itself

–        Can overdose

–        Eating a variety of foods beneficial

•          Two Categories of Vitamins:

–        Fat-soluble Vitamins:

•          A D E K

•          Stored in fat cells

•          Can be toxic faster than water-soluble vitamins

•          Deficiencies less common than water-soluble vits

–        Water-soluble Vitamins:

•          C and B-Complex

•          Dissolve readily in water & excreted in urine

•          harder to be toxic

•          Deficiencies occur more quickly

•          Vitamins

•          Vitamins C, E, and beta carotene (vitamin A precursor) function as antioxidants.

–        prevent oxygen free-radicals from combining with other substances and causing damage

–        Protects cell membranes and DNA from damage—believed to prevent heart disease, cancer, and emphysema

•          Minerals:

–        Zero calories

–        Smaller quantities

–        Mostly facilitators of body processes

–        Inorganic

–        Major minerals (>5 grams) & Trace minerals (<5 grams)

–        Extremely toxic if large amounts

•          Calcium and Iron deficiencies common

–        Calcium:

•          osteoporosis

–        Iron: iron deficiency anemia

•          Too much iron can cause infections, tissue damage, liver damage

•          Consult physician before taking iron supplementation

•          Water

–        Zero calories

–        Essential for life

–        Major component of blood

–        Helps body use other nutrients

–        Aids in digesting food

–        Electrolyte balance

–        Lubricates joints

–        Temperature regulation

•          Eight to ten 8-ounce glasses of water a day

–        More if necessary

•          Cannot always rely on thirst

–        Drink before necessary

•          Color of urine is an indicator

•          1 ½ hours to effect tissues (muscle)

•          Phytochemicals / Phytonutrients

•          Phytochemicals (phytonutrients), phytomedicinals, and antioxidants are the essential nutrients of the 21st century and may have dramatic effects on future guidelines.

•          Nutrition Acronyms

•          DRI (Daily Reference Intakes):

–        New “Umbrella” Term. Amounts of nutrients that best support health…4 values:

–        RDA (Recommended Dietary Allowance):

•          Nutrient intake sufficient to meet needs of nearly all healthy people in age/gender group. Considered generous.  Aim for this intake.

–        EAR (Estimated Average Requirement)

•          Using population average, amount necessary to maintain a specific body function.

–        AI (Adequate Intake):

•          Used when evidence is insufficient to set an RDA. Aim for this intake when RDA is not set.

–        TUIL (Tolerable Upper Intake Level):

•          Safe, upper limit of a nutrient.

•          EER (Estimated Energy Requirement):

–        Dietary “energy” intake to maintain energy balance.

•          DV (Daily Value):

–        Condensed system used on food labels. Based on a 2000 calorie diet--% of nutrient’s daily recommended intake.

•          Daily Values and Food Labels

•          FDA requires all nutrients in a food to be listed on a label

•          Every label must include:

–        Common name of product

–        Name & address of manufacturer, distributor, or packer

–        Net contents of package (count, measure, or weight)

–        Ingredients listed in descending order, with most plentiful first

–        If the product makes nutritional claims, the product must contain ”Nutritional Information” on label:

–        Serving or portion size

–        Servings per container

–        Calories per serving

–        Carbohydrates (grams) per serving

–        Fats (grams) per serving

–        Vitamins, minerals, and proteins (% RDA) per serving

–        Amounts of 8 “indicator nutrients” – protein, vitamin A, niacin, thiamin, riboflavin, vitamin C, calcium, and iron

•          Consumer Safety - Foods

•          Primary Concerns:

–        Additives

–        Irradiation

–        Food-borne illnesses

•          Food Additives

–        Chemical agents added to processed foods to preserve, improve appearance, enhance flavor

–        Antioxidants

•          BA & BHT – keep oils & fats from becoming rancid

–        Emulsifiers

•          suspend flavor oils throughout the product improving flavor & appearance

–        Preservatives

•          Inhibit bacterial growth for longer shelf life

•          Radiation

–        Improve quality of fresh & processed foods

–        Gamma Radiation increases shelf life and kills microorganisms that might have contaminated

–        Does not make food radioactive

–        FDA approved

•          Food-borne Illnesses

–        Food contaminated with bacteria or parasites

–        Examples:

•          Meat: E,coli bacteria (5%)

•          Poultry: Salmonella bacteria (25%)

•          Refrigeration doesn’t kill—must cook thoroughly

–        Signs & Symptoms:

•          nausea, vomiting, abdominal pain, bloating, gas diarrhea

•          Typically 5-8 hours after eating, but sometimes 30 minutes-several weeks later

•          2/3 restaurants; 1/3 home

•          To Protect Yourself from Food-Borne Illnesses:

–        Check expiration dates on all meat, poultry, fish

•          Eat in next few days or freeze

–        Refrigerate perishable foods

•          Unfrozen food no longer than 3 days in refrigerator

•          Refrigerator 40 degrees or less

–        Never thaw foods on the counter

–        Wash utensils & cutting boards thoroughly

–        Sanitize cutting boards at least once per week

–        Avoid eating raw eggs

–        Do not share utensils & cutting boards between raw meats and raw vegetables

–        Cook all meat, poultry, and fish thoroughly

•          Pork & chicken juices run clear; no pink

•          Meat cooked at least medium rare—more caution with ground meat with no traces of pink

–        Do not leave cooked foods standing at room temperature for longer than 2 hours

–        Never place cooked meat on the same plate that held the raw meat

•          How to Choose Nutritious Foods

•          Need at least 40 vitamins & Minerals, Fiber , Phyotochemicals, Energy, etc.

•          Eat a VARIETY of foods in MODERATION

•          USDA Food Guide:

–        Can help design an adequate and balanced diet

–        Defines major food groups and suggests portions from each group

–        Conveys key nutrients from each food group

–        Most nutrient-dense foods are recommended

•          Help to control overweight and obesity

•          MyPyramid

–        Educational tool to illustrate Dietary Guidelines and USDA Food Guide

–        Can create individualized diet plan

•          Nutrient Supplements

•          Billions of dollars spent each year

•          No supplement can give you all the nutrients you get from food

–        Example: phytochemicals

•          Times when nutrient supplements are useful

–        Deficiency

–        Energy intake below 1500 calories/day

–        If you know your diet will temporarily not be good

•          Follow directions for supplement use as provided by your health care provider

•          Change your diet before relying on a nutrient supplement