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Lesson 3.1 : Recommendations in Nutrition

Lesson 3.1 : Recommendations in Nutrition. Evolution of the Human Diet. At the conclusion of this session you should have an understanding of: the important characteristics of the hunter gatherer diet and lifestyle

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Lesson 3.1 : Recommendations in Nutrition

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  1. Lesson 3.1 : Recommendations in Nutrition

  2. Evolution of the Human Diet • At the conclusion of this session you should have an understanding of: • the important characteristics of the hunter gatherer diet and lifestyle • the impact of the domestication of plants and animals on the human diet and lifestyle • the major changes in dietary composition through human history • the western diet in evolutionary perspective, and the health implications

  3. Paleolithic nutrition • Is this the type of diet for which humans are genetically programmed? • the human genome has changed little since paleolithic times • Behaviours and preferences which favoured survival of humans in the past may explain why diet and lifestyle have evolved as they have • maximising energy intake • minimising energy output • The therapeutic and preventive potential of the principles of the hunter gatherer diet (and lifestyle)

  4. Why study the evolution of the human diet? • Insights into: • health implications of our current diet and lifestyle • role of diet in the pathogenesis, prevention and treatment of a range of diet-related chronic diseases • CVD • type 2 diabetes • obesity • cancers

  5. HOW? • archeological record • plant analysis, DNA analysis, radiocarbon and other dating techniques • surviving hunter gatherer populations • Australian Aborigines • subsistence agriculture • nutrient analyses of edible components of uncultivated plant foods and non-domesticated animals • molecular genetics • wild progenitors of current staple foods

  6. Limitations • incomplete nature of archeological evidence • animal remains more robust than plant remains • large mammal bones most likely to survive • limitations of dating techniques • radiocarbon dating to 40,000 yr • recent hunter gatherers retreated to marginal locations • may not be typical of paleolithic times • PCR techniques - risk of contamination

  7. Key events in human evolution • Timeline years b.p. • Homo Habilis 2 million • Homo Sapiens 400,000 • Homo Sapiens Sapiens 100,000 • Agriculture 10,000 • Industrial revolution 200

  8. Transition to agriculture • Paleolithic times • focus on big game hunting • over hunting, extinction of large species • Shift to broader spectrum hunting and gathering • small game, fish and shell fish • more plant food, including seeds • grinding stones, mortars, pestles • Agriculture developed in locally rich locations, eg, Fertile Crescent

  9. The emergence of agriculture • developed independently in widely separated locations around the world • pressure on food supply • over hunting • climate change • population growth • sedentary communities in rich locales • role of humans in selecting plants and animals for domestication and in subsequent breeding programs • greater yields • capacity to support larger populations

  10. Plants already important in the diet selected to increase yield and improve palatability energy density fibre starch fat Animals gregarious, non-carnivorous selected to increase yield and manageability smaller size more fat greater milk output Plant and animal breeding

  11. The western diet • The consequence of human evolution • “Land of milk and honey” • high energy density • low energy output

  12. The western diet • The exception in human history • high energy density • reduced micronutrient density • excess available energy • high in saturated fat • high in refined CHO, low in fibre • high n-6/n-3 PUFA ratio • high Na, low K

  13. The ‘Mediterranean’ diet • Based on the Cretan diet, 1960’s • ‘modified fat’ rather than low fat • high proportion of monounsaturated fat (olive oil) • high intake of vegetables and fruit • vegetables consumed with olive oil • increases the bioavailability of lipid soluble phytochemicals such as carotenoids • legumes • fish • relatively low meat intake

  14. Diet-related diseases of western lifestyle • Obesity • Cardiovascular diseases • CHD, stroke, hypertension • Diabetes • Certain cancers • colon, prostate, breast • Osteoporosis • Non-infective bowel diseases

  15. Learn from history! Incorporate the best of traditional diets and cuisines hunter gatherer Mediterranean Asian Middle east Incorporate other features of traditional lifestyles Ecological sustainability Continue as before More and better ways of processing foods The illusion of great variety ‘Foodaceuticals’ Health claims Health consequences Evolution of the human diet: two future scenarios

  16. Wild fat 29% CHO 30% protein 13% fiber 11% Cultivated fat 59% CHO 7% protein 17% fiber 7% Nutrient composition of wild and uncultivated nuts Brand-Miller et al, 1998

  17. Nutrition • Deficiency Diseases are rare • Current Problems: • Excessive Calorie Intake • Nutrient Imbalance • Too much of a good thing!!

  18. RDAs • Recommended Dietary Allowances • Average amount of nutrients that should be consumed over time • 2 ways to meet RDA • Follow 7 Dietary Guidelines • Follow Food Guide Pyramid

  19. Nutrients 6 Basic Elements: • Carbohydrates • Fat • Protein • Vitamins • Minerals • Water

  20. Calories provided by: • Carbohydrates (1 gram: 4 calories) • Fat (1 gram: 9 calories) • Protein (1 gram: 4 calories) *1 gram of Alcohol provides 7 calories (non-nutritive/empty calories)

  21. Recommended % of calories to obtain from each macronutrient • Carbohydrates: 50 - 55% • 45% complex • 10% simple • Fat: 25 - 30% • 10% Monounsaturated • 10% Polyunsaturated • <10% Saturated • Protein: 15 - 20%

  22. Daily Reference Values (DRVs) • Recommended grams or mg for selected nutrients 2000 Calorie a day diet: • Fat: 65 grams • Cholesterol: <300 mg • Sodium: <2400 mg • Carbohydrate: 250 - 300 g • Fiber 20 - 30 g • Potassium: 3000 - 3500 mg

  23. Protein Functions: • Tissue growth/repair; forms parts of blood, hormones, enzymes, cell membranes Made up of amino acids (approx. 20) • 9 essential amino acids (must be supplied by foods)

  24. “Complete Protein • Contains all essential amino acids • Animal sources (careful with fats) • Combined plant sources • Plant proteins are incomplete • e.g. peanut butter sandwich is a protein complement

  25. How much protein is necessary? How much? • .8 grams per kilogram of body weight (wt in lbs/2.2) Excess Protein: • Converted to fat • Strains kidneys • Body excretes calcium

  26. Major Sources • Meat, poultry, fish, eggs, milk and milk products, dry beans and peas, nuts • Choose low fat sources!

  27. Carbohydrates • Functions: • Major source of energy • Essential for functioning of CNS

  28. Simple Carbohydrates • Sugars • Rapidly absorbed • Major sources: corn syrup, sugar, honey, "ose" endings

  29. Complex Carbohydrates *Starch: • Converts to glucose • Provides steady energy source *Glycogen: Storage form of glucose

  30. Sources Plant foods: • Grains • Tubers (potatoes) • Legumes (beans and peas)

  31. Fiber • Part of food that resists digestion • Insoluble fiber • Not digested by the body • Whole grains, wheat bran, skin of fruits & vegetables • Aids gastrointestinal function • Increases bulk in stool & prevents constipation • Reduces risk of colon cancer • Soluble fiber • Found in grains (oats), fruits, vegetables • Lowers cholesterol levels • Prolongs sense of fullness

  32. Fats Functions: • insulates • cushions organs • carries fat soluble vitamins • energy source • raw material for hormones

  33. Negative effects • Obesity • Increased cancer risk (breast, colon, uterus) • Gall bladder disease • Coronary disease (elevated cholesterol)

  34. Types of Fats • Saturated • mostly animal origin, egg yolks, lard, etc. • Polyunsaturated • safflower, corn oil • Monounsaturated • canola, olive oil • Omega-3 Fatty acids • fish oils from fish not supplements • *The less saturated the better!

  35. Cholesterol • Fat-like substance • Used to form cell membranes, hormones • Endogenous and exogenous sources • Carried by lipoproteins

  36. LDL and HDL • LDL: Low density lipoprotein • Most likely to cause atherosclerosis • HDL: High density lipoprotein • Removes excess cholesterol

  37. Cholesterol Lowering Tips • To Lower LDL • Lower saturated fat intake • Lower dietary cholesterol intake • To Raise HDL • Exercise • Quit smoking • Moderate alcohol intake

  38. Nicotine • Contributes to 30% of coronary deaths • Adversely affects LDL/HDL • Constricts blood vessels • Increases oxygen requirement • Increases blood viscosity • Linked with osteoporosis

  39. Vitamins • Organic compounds • Helpers of bodily processes • Fat soluble (A,D,E,K) • Water soluble (B vitamins, C) • Folate helps prevent neurological birth defects • Antioxidants (C, E, beta carotene) • Destroy free radicals

  40. Minerals • Inorganic • 7 Major minerals • calcium, phosphorous, sodium, potassium, sulfur, sodium, chloride, magnesium • Trace minerals • Very small amounts needed • 14 are essential to good health • iron, zinc • Be weary of mineral supplements! *Calcium and iron: especially important for women.

  41. Water • “The forgotten nutrient” • 8-10, 8-ounce glasses per day (minimum) • Alcohol, caffeine, increases need for H2O • Functions: • transport nutrients • carries away waste • regulates body temperature

  42. Health Related Fitness • Cardiorespiratory endurance • the ability to use oxygen for physical work • Muscular strength • ability to exert maximum force against resistance • Muscular endurance • ability of a muscle to exert sub-maximal force repeatedly • Flexibility • range of motion at a joint • Body Composition • amount of lean vs fat tissue in the body

  43. Aerobic Capacity • Decreases with age • Decreases rapidly when training is discontinued

  44. Benefits of Aerobic Exercise • Research has proven all of the following benefits: • Lowers LDL, triglycerides • Raises HDL • Improves body composition • Reduces BP • Platelets less sticky • Improves functioning of CV system • Stronger heart • Lowers resting heart rate

  45. Benefits of Aerobic Exercise • Helps control diabetes • Strengthens bones • Promotes joint stability • Reduces stress • Improves self-concept • Helps prevent lower back problems • Encourages other positive lifestyle changes

  46. Principles of Conditioning • Intensity: how vigorous Karvonen Formula THR= (MHR-RHR = HRR) X TI% + RHR MHR= 220-age; HRR= heart rate reserve • Choose intensity based on fitness level: Low: 60% Fair: 65% Avg: 70% Good: 75% Exc.: 80-90%

  47. Daily Routine • Warm-up • 5-10 minutes • Gradually elevate heart rate • Increase muscle temperature • Mild stretching • Exercise component • 20 to 30 minutes • Cool-Down • 5-10 minutes of Light activity • Returns blood from muscles back to heart for redistribution • Aids in removal of metabolic waste products • No cool down? Possible dizziness, fainting

  48. Frequency: How often? 3-5 days per week • Duration: 20-30 minutes • Intermittent activity is OK • Low intensity/longer duration is better for health enhancement!

  49. Hypertension • Silent Killer • No symptoms • Blood pressure: force exerted against arterial walls • Systolic: pressure when heart contracts • Diastolic: pressure in between beats

  50. Treatment • Weight loss • Smoking cessation • Reduce salt • Reduce alcohol • Potassium and calcium supplementation • Relaxation • Exercise • Medication

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