Introduction to Clinical Nutrition (Medical Nutrition Therapy)

Clinical Nutrition

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Purpose

To achieve or maintain good nutritional status

Patient Care

Team Approach (interdisciplinary)

Care Process

Patient-centered

Assessing Nutritional Status

Historical Information

Physical Examination

Anthropometric Data

Laboratory Analyses

Historical Information| Health History (Medical History)

risk factors for disease

food intake

conditions

emotional and mental health

Historical Information| Drug History

side effects of drugs to the patient

Historical Information| Socioeconomic History

purchasing power of the patient

Historical Information| Diet History

analyze amount of food taken

adequacy of intake

supplements that overlaps patient medication

Tools for taking diet history

24 hour recall

usual intake

food frequency questionnaire/checklist

food records

observing food intake

Physical Examination

* weight status
* mobility
* sighns of nutrient deficienies/ malnutrition
* fluid balance

Anthropometric Data

physical measurement of the body

indirect assessment of body composition and development

anthropos; metric

human; measure

Ideal Body Weight

person’s body composition has a good balance of lean body mass and fat tissue

Body Mass Index (BMI)

Weight (kg)÷height (m^2)

* Underweight <18.5
* Normal 18.5-24.9
* Overweight 25.0-29.9
* Obese Class 1 30 to < 35
* Obese Class 2 35 to < 40
* Obese Class 3 40 or higher

Skin-fold Measurements

* not used to assess or monitor weight status
* half of total body fat is directly under the skin
* measure in multiple sites

Skin-fold Measurement Sites

* Abdomen - next to the belly button (horizantal)
* Midaxilla - midline of the side of the torso (vertical)
* Pectoral - mid-chest, forward of the armpit (vertical)
* Quadriceps - middle of the upper thigh (vertical)
* Subscular - beneath the edge of the shouldder blade (vertical)
* Suprailiac - above the iliac crest of the hip bone (diagonal)
* Triceps - back of the upper arm (vertical)

Percent Body Fat

* Very Low Fat (skinny) - Men (7-10); Women (14-17)
* Low Fat (Thin) - Men (10-13); Women (17-20)
* Average (normal) - Men (13-17); Women (20-27)
* Above Normal (Plump) - Men (17-25); Women (27-31)
* Very High (Fat) - Men (>25); Women (>31)

Waist to Hip Ratio

* Abdominal ratio
* Measure body fat distribution and adiposity
* Waist - measured at the narrowest point under the last rib (cm)
* Hip - measures at the widest point of the buttock (cm)
* Waist Circumference ÷ Hip Circumference
* >/= 1 in men = obese; >/= in women = obese
* Men >102 cm waist cicumference = obese
* Women >88 cm waist cicumference = obese

Mid Upper Arm Circumference (MUAC)

* evaluate fat stores
* measure the arm, muscle mass, subcutaneous fat and bone
* estimates wasting of an individual

Mid Upper Arm Circumference (Children 1-5)

* Normal | >14
* Mild/moderate malnutrition | 12.5 - 14
* Severe malnutrition | <12.5

Mid Upper Arm Circumference (Adults)

* Normal | >/= 23 (male); >/= 22 (female)
* Malnourish | < 23 (male); < 22 (female)

Desirable Body Weight

* Infant: birth weight (gm) + age in mo. x 600
* 2 years and above (until 12): dbw (k) = age in years x 2 + 8
* Teens and adults: dbw (k) = height (cm) - 100 (if south asian or caucasian stop here)
* -10% (south east asian; + 3 tas -2)
* Amputees: dbw x % total weight of patient

Nutritional Assessment | Biochemical Analysis

* Serum proteins
* Nitrogen balance

Serum Proteins

* Estimate visceral protein reserve
* overall poor reliability due to complex factors
* Overall markers include
* total serum protein, albumin, tansferrin and total lymphocyte count
* due to long half live refleccts chronic malnutrition
* More sensistive markers due to shorter half live
* pre-albumin, retinol binding prtein, ceruloplasmin
* reflects acute changes in nutritional status

Nitrogen Balance

* Measure protein synthesis and breakdown
* protein intake is the sum of all nitrogen intake (enteral and peranteral)
* protein breakdown is measures by nitrogenexcretion in urine, feces, fistula etc.
* Calculations
* N intake = g protein / 6.25
* N output = (urine urea *urine volume/day(l)* 0.028) + losses (3-6g)
* Balance
* Positive = anabolism
* Negative = catabolism
* Mild 5-10 g
* moderate 10-15 g
* severe 15g

Metabolism

* sum energy expenditure of all bodily functions
* both voluntary and involuntary

Oxidation

part of the metabolic process in which your body processes food for fuel

Nutrition

science of how living organisms obtain and use food to support all the processes required for their existence

Nutrient

substance used by the body for growth, maintenance, and repair

Categories of Nutrients

* carbohydrates
* lipids
* proteins
* vitamins
* mineral
* water

Catabolism

* substances are broken down to simpler substances


* energy is released

Anabolism

larger molecules are built from smaller ones

Cellular Respiration

* oxygen using events take place within the cell to create atp from adp
* carbon leaves cells as carbon dioxide
* Hydrogen atoms are combined with oxygen to form water
* Energy produced by these reactions adds a phosphorus to ADP to produce ATP
* ATP can be broken down to release energy for cellular use

Metabolic Pathways

* Glycosis
* Krebs Cycle
* Electron Transport Chain

Glycosis

energizes a glucose molecule so that it can be split into two pyruvic acid molecules and yield ATP

Krebs Cycle

* produces cirtually all the carbon dioxide and water resulting from cell respiration
* yields a small amount of ATP
* splits carbon, hydrogen, oxygen bond to create ATP again
* combines carbon and oxygen to produce carbon dioxide (by product of krebs cycle)

Electron Transport Chain

* hydrogen atoms removed during glycosis and the krebs cycle are delivered to protein carriers
* Hydrogen is split into hydrogen ions and electrons in the mitochondria
* Electrons give off energy in a series of steps to enable the production of ATP
* Hydrogen ions + oxygen = water (by product of ETC)

Fat Metabolism

* handled mostly by the liver
* use fats to make ATP
* synthesize lipoproteins, thromboplastin, and choleterol
* release breakdown products to the blood
* body cells remove fat and cholesterol to buil membranes and steroid hormones

Use of fats for ATP synthesis

* broken down acetic acid = ammonia = uric acid = produce carbon dioxide and ATP

Protein Metabolism

* used for most cellular structures
* use rarely for fuels; for starvation
* ingested broken down to amino acids
* Cells remove amino acids to build proteins
* Synthesized proteins are actively transported across cell membranes
* Amino acids are used to make ATP only when proteins are overabundant

Production of ATP from protein

* Amine groups are removed from proteins as ammonia
* The rest of the protein molecule enters the Krebs cycle in mitochondria
* The liver converts harmful ammonia to urea which can be eliminated in urine

Role of the liver in Metabolism

* Several roles in digestion
* Detoxifies drugs and alcohol
* Degrades hormones
* Produce cholesterol, blood proteins (albumin and clotting proteins)
* Plays a central role in metabolism

Metabolic functions of the liver

* glycogenesis
* glycogenolysis
* gluconeogenesis

Glycogenesis

* glucose molecules are converted to glycogen
* glycogen molecules are stored in the liver

Glycogenolysis

Glucose is released from the liver after conversion grom glycogen

Gluconeogenesis

Glucose is produces from fats and proteins

Metabolic Functions of the Liver

* Fats and fatty acids are picked up by the liver
* Some are oxidized to provide energy for liver cells
* The rest are broken down into simpler compounds and released into the blood

Cholesterol Metabolism

most cholestorol is produced in the liver and is not from diet

Cholesterol

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Function

* structural basis of steroid hormones and vitamin D
* major buliding block of plasma membrane

Cholesterol Transport

* cholesterol and fatty acids cannot freely circulate in the bloodstream
* they are transported by lipoproteins (lipid-protein complexes
* Low - density lipoproteins (LDLs)
* High - density lipoproteins (HDLs)

Low-density lipoproteins (LDLs)

* transport lipid towards body cells
* increase storage of fat in cells
* should be low

High-density lipoproteins (HDLs)

* transport body cells to the liver
* fat from cell to be in liver to metabolize
* should be high

Body Energy Balance

* Energy intake = total energy output (heat + work + energy storage)
* most of our body fuel = create heat (60%)

Regulation of Food Intake

* body weight is usually relatively stable
* Energy intake and output remain about equal

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Mechanisms that may regulate food intake

* levels of nutrient in the blood - cravings = kulang vitamins
* hormones - pregnant = naglilihi
* body temperature - malamig = gutom
* psychological factors

Basic Metabolic Rate

amount of heat produced by the body per unit of time at rest

Factors that influence BMR

* Surface area – small body usually has higher BMR
* Gender – males tend to have higher BMR
* Age – children and adolescents have a higher BMR
* The amount of thyroxine produced is the most important control factor
* More thyroxine means higher metabolic rate

Total Metabolic Rate

* Total amount of kilocalories the body must consume to fuel ongoing activities
* increases with an increase in body activity
* must equal calories consumed to maintain homeostasis and maintain a constant weight