Bio Malnutrition p 1

7/31/2019 Bio Malnutrition p 1

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The cycle of malnutritionHow and where to break the cycle isthe issueThe focus of intervention is now on theLifecycle or life course


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Types of MalnutritionOvernutritionSecondary malnutritionMicronutrient malnutritionProtein Calorie malnutrition


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Overnutrition

Too many calories leading to obesity,diabetes, hypertension and cardiovasculardisease

Transition diets now a consideration of WHO due to increase worldwide in chronicdisease due to dietary change


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OvernutritionOn a global basis 79 % of all deathsattributable to chronic disease arealready occurring in developingcountries

Public health implications are staggering

Overnutrition following fetalmalnutrition has also been linked tochronic disease risk in adulthood


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Secondary MalnutritionCondition that prevents proper digestion

or absorptionOften accompanies and exacerbatesother types of malnutrition


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Secondary Malnutrition- causativeconditions

Loss of appetite

Alteration of normal metabolismduring infection/feverHIV/AIDS

Prevention of nutrient absorptionDiarrheal infection causing changes in GIepithelium


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Secondary Malnutrition- causativeconditions

Diversion of nutrients to parasitic agentsthemselves

Hookworms, tapeworms, schistosome wormMalaria


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Children with Intestinal Parasites(courtesy of WHO)


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Prevention of nutrient diversionSanitary waste disposal and clean waterimportant in reducing secondarymalnutrition

Prevention of transmission of parasites anddiarrheal diseases

Hookworm acquired by walking barefoot overcontaminated soilOther roundworm infections use oral-fecal route


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Prevention of nutrient diversionSoap an important factor in nutritionalstatusEducation of women extremely importantin this regard


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Micronutrient MalnutritionDietary Deficiencies of

Vitamin A IodineIronOthers: Zinc, vitamins D, C, and Bs


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Protein Calorie MalnutritionMore food needed for normal growth,health and activityRarely have protein deficiency withoutcaloric deficiency due to the nature of thefood supplies

exception seen with cassava and plantain asstaples


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Role of caloriesInvoluntary use: breathing, bloodcirculation, digestion, maintaining muscletone and body temperaturePhysical activityMental activityFighting diseaseGrowth


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Role of proteinFor building cells that make up muscles,

membranes, cartilage and hairCarrying oxygenNutrient transport

AntibodiesEnzymes needed for most chemical reactionsin the body


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What happens to people when theyhave inadequate amounts of food and nutrients?

Metabolic changesPhysiologic changes

Psychological changes


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Metabolic Response to StarvationHunger subsides after 2-3 daysDefecation ceases after 3-4 daysUrine output drops after 1 week in themajority of people to 100-700 ml/dayBlood glucose levels drop to 35 to 65 mg/dlwithout clinical signs of hypoglycemiaNausea occurs in about 1/3 from ketoneproduction from body fat breakdown


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Metabolic Response to Starvation

Serum electrolytes do not changeRenal conservation occurs promptlyRarely see low potassium in prolonged fast


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Metabolic Response to StarvationNegative nitrogen balance - 1 st 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 produceglucose (gluconeogenesis), using about 75grams per day of protein

This is equal to lb of wet tissue per day About 160 gm per day of body fat is also used


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Metabolic Response to StarvationNegative nitrogen balance

Gradually 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 cells


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Metabolic Response to StarvationGradual shift in metabolic fuels

First glucose is produced from protein

breakdown to provide energyThen fat breakdown and metabolism providesketones for all tissues except CNS, RBC andWBC

Brain will eventually use ketones but red blood cellshave no mitochondria, so must use glucoseSerum fatty acid levels increaseSerum albumin is normal until late in starvation


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Production of Ketones


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Metabolism


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Metabolic Response to StarvationHormonal changes

Plasma insulin decreases

Plasma cortisol and growth hormone stay thesame and glucagon increasesThese changes are responsible for the

mobilization and oxidation of fat storesChanges in sympathetic nervous system andmetabolism of thyroid hormone lowers basalmetabolic rate


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Metabolic Response to StarvationWeight loss

First week 0.7 to 1.3 kg per day, much of

which is slat and water loss After the first week 0.3 to0.5 kg/day

Basal Metabolic Rate and Total Energy

Expenditure decrease in prolongedstarvation

See decreased activity, increased sleep

Decrease in body temperature


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Classic study by Keyes described physicaland psychological changes during a periodof semi-starvation.

Traditionally used to describe what happensduring dietingPerhaps should think about traditional

stereotypes of the poor in relationship to thefindings of this study


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Keyes StudyImpetus: realization WWII would be oversoon and food relief was going to be

necessary needed dataSubjects:32 menConscientious objectors

Ages 25.5 +/-3.5 yearsTime period:

11/19/44 to 1/20/45


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Keyes Study -Diet 12 weeks of baseline diet ad lib

Normal diet of 51% carbohydrate, 13%protein, 32% fat

24 week semi-starvation diet12 weeks of rehabilitation (normaldiet)


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Keyes Study24 week semi-starvation diet

Consisted of food designed to represent the

types of foods available in European famineareas whole wheat bread, potatoes, cereals,considerable amounts of turnips and cabbage,token amounts of meat and dairy products

About 1600 kcal per day, 71% carbohydrate,12% protein and 17% fatServed in 2 meals per day at 8:30AM and 5 PM


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Keyes Study - Activity Assigned specific tasks such as generalmaintenance, laboratory assistance,shop duties and desk work about 15hours per week Educational programs, about 25 hours

per week Walked 35 km out-of-doors per week and were on a treadmill for hour


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Keyes Study Body changesBody weight decreased about 25%From mean of 69.4kg (BMI 21.4) to 52.6 kg

(BMI 16.3)Weight loss decreased progressively andnearly reached a plateau at the end of the

semi-starvation periodSubjects adjusted their energy expenditure toreach a balance after 24 weeks at 45% of thead lib diet


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Keyes Study - Adaptations

Adaptation accompanied by a loss of activetissue

Relatively high loss of lean body massBody fat loss made up about 1/3 of the weightchange


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Keyes Study - AdaptationsReduced activity costs were the mainpart of the energy savings

Decrease BMR due to less lean body massLess thermic effect of food due to lowerintake

Reduced body weight resulting in lesscaloric cost of physical activity


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Keyes Study - Adaptations Real adaptation

Reduction in tissue metabolism Decreased BMR

Reduction in physical activity


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Keyes Study Physical signs After about 3 months, participantscomplained of

FatigueMuscle sorenessIrritabilityHunger pains


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Keyes Study Physical signs After 3 months, participants

Exhibited a lack of

Ambition Self-discipline Poor concentration

Were often moody and depressedBecame less able to laugh heartily, sneeze andtolerate heatHeart rate and muscle tone decreased


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Keyes Study - recoveryWhen permitted to eat normally again,the desire for more food and a feelingof fatigue continued, even after 12weeks of rehabilitation.Full recovery required 33 weeks.


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Study QuestionsWhat are the implications of this researchto population groups with cyclical foodavailability?What might happen to the capacity towork with undernutrition?

Bio Malnutrition p 1

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