The Biology of MalnutritionThe cycle of malnutritionSlide 3Types of MalnutritionOvernutritionSlide 6Secondary MalnutritionSecondary Malnutrition- causative conditionsSlide 9Children with Intestinal Parasites (courtesy of WHO)Prevention of nutrient diversionSlide 12Micronutrient MalnutritionProtein Calorie MalnutritionRole of caloriesRole of proteinWhat happens to people when they have inadequate amounts of food and nutrients?Metabolic Response to StarvationSlide 19Slide 20Slide 21Slide 22Production of KetonesMetabolismSlide 25Slide 26Slide 27Slide 28Keyes StudyKeyes Study -DietSlide 31Keyes Study - ActivityKeyes Study – Body changesKeyes Study - AdaptationsSlide 35Slide 36Keyes Study – Physical signsSlide 38Keyes Study - recoveryStudy QuestionsThe Biology of MalnutritionThe cycle of malnutritionHow and where to break the cycle is the issueThe focus of intervention is now on the Lifecycle or life courseTypes of MalnutritionOvernutritionSecondary malnutritionMicronutrient malnutritionProtein Calorie malnutritionOvernutritionToo many calories leading to obesity, diabetes, hypertension and cardiovascular disease“Transition diets” now a consideration of WHO due to increase worldwide in chronic disease due to dietary changeOvernutritionOn a global basis 79 % of all deaths attributable to chronic disease are already occurring in developing countriesPublic health implications are “staggering”Overnutrition following fetal malnutrition has also been linked to chronic disease risk in adulthoodSecondary MalnutritionCondition that prevents proper digestion or absorptionOften accompanies and exacerbates other types of malnutritionSecondary Malnutrition- causative conditionsLoss of appetiteAlteration of normal metabolism during infection/fever HIV/AIDS Prevention of nutrient absorptionDiarrheal infection causing changes in GI epitheliumSecondary Malnutrition- causative conditionsDiversion of nutrients to parasitic agents themselvesHookworms, tapeworms, schistosome wormMalariaChildren with Intestinal Parasites(courtesy of WHO)Prevention of nutrient diversionSanitary waste disposal and clean water important in reducing secondary malnutritionPrevention of transmission of parasites and diarrheal diseasesHookworm acquired by walking barefoot over contaminated soilOther roundworm infections use oral-fecal routePrevention of nutrient diversionSoap an important factor in nutritional statusEducation of women extremely important in this regardMicronutrient MalnutritionDietary Deficiencies ofVitamin AIodineIronOthers: Zinc, vitamins D, C, and BsProtein Calorie MalnutritionMore food needed for normal growth, health and activityRarely have protein deficiency without caloric deficiency due to the nature of the food supplies exception seen with cassava and plantain as staplesRole of caloriesInvoluntary use: breathing, blood circulation, digestion, maintaining muscle tone and body temperaturePhysical activityMental activityFighting diseaseGrowthRole of protein For building cells that make up muscles, membranes, cartilage and hairCarrying oxygenNutrient transportAntibodiesEnzymes needed for most chemical reactions in the bodyWhat happens to people when they have inadequate amounts of food and nutrients?Metabolic changesPhysiologic changesPsychological changesMetabolic Response to StarvationHunger subsides after 2-3 daysDefecation ceases after 3-4 daysUrine output drops after 1 week in the majority of people to 100-700 ml/dayBlood glucose levels drop to 35 to 65 mg/dl without clinical signs of hypoglycemiaNausea occurs in about 1/3 from ketone production from body fat breakdownMetabolic Response to StarvationSerum electrolytes do not changeRenal conservation occurs promptlyRarely see low potassium in prolonged fastMetabolic Response to StarvationNegative nitrogen balance - 1st 5 to 7 days 12 to 15 grams of nitrogen per day is excreted in the urine (based on 1800 kcal daily needs)Skeletal muscle is catabolized to produce glucose (gluconeogenesis), using about 75 grams per day of protein•This is equal to ¾ lb of wet tissue per dayAbout 160 gm per day of body fat is also usedMetabolic Response to StarvationNegative nitrogen balanceGradually slows so that at about 1 month•2-4 grams of nitrogen is loss per day•Skeletal muscle catabolism decrease significantly–Only for cells that have to have glucose–Central nervous system–Red blood cells–White blood cellsMetabolic Response to StarvationGradual shift in metabolic fuelsFirst glucose is produced from protein breakdown to provide energyThen fat breakdown and metabolism provides ketones for all tissues except CNS, RBC and WBC•Brain will eventually use ketones but red blood cells have no mitochondria, so must use glucoseSerum fatty acid levels increaseSerum albumin is normal until late in starvationProduction of KetonesMetabolismMetabolic Response to StarvationHormonal changesPlasma insulin decreasesPlasma cortisol and growth hormone stay the same and glucagon increasesThese changes are responsible for the mobilization and oxidation of fat storesChanges in sympathetic nervous system and metabolism of thyroid hormone lowers basal metabolic rateMetabolic Response to StarvationWeight lossFirst week 0.7 to 1.3 kg per day, much of which is slat and water lossAfter the first week 0.3 to0.5 kg/dayBasal Metabolic Rate and Total Energy Expenditure decrease in prolonged starvationSee decreased activity, increased sleepDecrease in body temperatureClassic study by Keyes described physical and psychological changes during a period of semi-starvation.Traditionally used to describe what happens during dietingPerhaps should think about traditional stereotypes of the poor in relationship to the findings of this studyKeyes StudyImpetus: realization WWII would be over soon and food relief was going to be necessary – needed dataSubjects: 32 menConscientious objectorsAges 25.5 +/-3.5 yearsTime period:11/19/44 to 1/20/45Keyes Study -Diet12 weeks of baseline diet ad libNormal diet of 51% carbohydrate, 13% protein, 32% fat24 week semi-starvation diet12 weeks of rehabilitation (normal diet)Keyes Study24 week semi-starvation dietConsisted of food designed to represent the types of foods available in European famine areas – whole wheat bread, potatoes, cereals, considerable amounts of turnips and cabbage, token amounts of meat and dairy productsAbout 1600 kcal per day, 71% carbohydrate, 12% protein and 17% fatServed in 2 meals per day at 8:30AM and 5 PMKeyes Study