Nutritional Assessment

Nutritional Screening

the process of identifying characteristics known to be associated with nutritional problems

Nutritional Screening

May consists of a questionnaire, or interview, which identifies eating habits, food allergies and intolerance, dietary restrictions, special diets, recent weight loss, history of illness, and hospitalization.

person's nutriture

measured by anthropometric, biochemical, clinical, and dietary methods

Nutritional Surveillance

Is carried out by regular or periodic evaluation of measurements that can be used to indicate present as well as future changes in nutritional status.

Nutritional Surveillance

It involves monitoring activities and events that are expected to have a direct or indirect bearing on nutritional status.

A - anthropometric

B - biochemical

C - clinical

D - dietary measurements

Four General Methods Of Nutritional Assessment

NUTRITIONAL ASSESSMENT

to collect basic data on nutritional status of the population to be used as guide planning, formulation and modifications of action programs intended to improve the nutrition and health of the community/population

Anthropometric Assessments

Are inexpensive and easily obtained; are used useful to supplement other indicators of nutritional assessments; should be repeated on an individual to note the degree of change in nutritional status overtime.

Anthropometric Assessments

Height and weight are the most commonly performed measurements; actual current measurements should be used whenever possible, which are then compared with standards.

1. can detect early sub-clinical status of nutrient deficiency.

2. can identify specific nutrient deficiency.

3. are independent of the emotional and subjective factors.

Biochemical Assessment advantages

1. they are expensive and time-consuming

2. standards could vary with wide range

3. there may be problems in interpreting results

Biochemical Assessment disadvantages

Clinical Assessment

the physical examination (P.E.) of an individual for signs and symptoms suggestive of nutritional health and/or clinical pathology

signs

come late in the pathogenesis of a disease

biochemical tests

can detect early malnutrition states

Clinical examinations

conducted by the physician on anatomic changes that can be seen or felt in the superficial, epithelial tissues

Dietary Assessments - Retrospective

food recalls and food frequency questionnaire

Dietary Assessments - Prospective

food records are the most used method

Qualitatively

use of food pyramid or food groups as guide

Quantitatively

calculating specific nutrients and calories with the use of software, FCTs or food exchange lists

24 hour food recall

Detailed and supplements, along with portion sizes in common household measures is included.

24 hour food recall

This method is useful in screening or during follow-up to evaluate adaption of dietary recommendations.

24 hour food recall advantages

it is quick (takes about half an hour) and it can be used with any age group. Since it is retrospective, the patient does not modify his or her actual intake. The information can be obtained by interview, telephone, or by self-reporting.

24 hour food recall disadvantage

they rely on the memory motivation, and awareness of the person. It is limited to 24 hours of intake, which may be not typical of his/her daily diet

Food Frequency Questionnaire (FFQ)

is an easy form to follow, although it could be time-consuming, defending on the number of pages listing foods and beverages to study the food habits and choices of a person

Food Frequency Questionnaire (FFQ)

a questionnaire listing foods on which individuals indicate how often they consume each listed item during certain time intervals (daily, weekly, or monthly). Standard portion sizes are used and an estimate of nutrient intake is provided on the questionnaire

Food Frequency Questionnaire (FFQ)

cannot be used for quantitative analysis of daily diets

Semi-Quantitative Food Frequency Questionnaire (FFQ)

a food frequency questionnaire that assess both frequency and portion size of food consumption

Food Records

can provide more realistic picture of a patient's usual intake. All food items, beverages, snacks, and supplements are recorded by the patient, usually over a period of 3 to 7 days using household measures

Food Records

To assure accuracy, the patient must be trained with food models, measuring cups, or other measuring devices that will help ensure recording of proper or actual portion sizes.

Food Records

Cooking methods, recipe ingredients and description need to be recorded as detailed as possible. Respondents often fail to write down spices and seasonings & sugar.

Food Records

Certain medicines that have nutrient interactions or nutritional supplements should be recorded, if such information are important for a more accurate nutritional assessment.

Food Records

The recorder may be asked to monitor or write down locations, times, events, and feelings, state of appetite, to identify behavioral influences on diet intake.

Food Records

7-day food record is considered to be optimal for gathering this kind of information, because it includes weekends.

Food Records

Shorter periods like a 3-day record (two weekdays and one weekend day) may be acceptable.

energy

the capacity to do work

energy

all the vital processes of the human body require energy

calorimetry

the measurement of heat or energy produced by food of the body

Kcal

it is also the unit of measure of heat or energy derived from foodstuffs

kcal

The amount of heat required to raise the temperatures of one kg of water by one degree centigrade (or Celsius) at normal atmospheric pressure.

1 kcal =

1000 small calories (c)

joule

unit of energy in the metric system

1 c =

4.184 joules

direct method

measurement of the amount of energy expanded by monitoring the amount of heat produced inside a chamber large enough to permit moderate amounts of activity; makes use of bomb calorimeter or a respiration chamber as instruments to measure heat production directly

indirect method

measurements of the amount of energy expanded by monitoring the oxygen consumption and carbon dioxide production of the body over a period of time

Bomb calorimeter

direct method (1)

Bomb calorimeter

A well-insulated box-like container about a cubic foot in size, used to measure the heat produced by a known amount of food when it is burned inside.

Bomb calorimeter

An instrument that measures the heat energy released when foods are burned, thus providing an estimate of the potential energy of foods.

Bomb calorimeter

A weighted amount of food is placed in the chamber of the calorimeter and the instrument is immersed in water. When the food is ignited in the presence of oxygen, the increase in temperature of the surrounding water indicates the number of Kcal given off by the oxidation of food.

heat of combustion or gross energy value of food

When the food is ignited in the presence of oxygen, the increase in temperature of the surrounding water indicates the number of Kcal given off by the oxidation of food.

Respiration Chamber

A small, well-insulated room that operates on the same principle as the bomb calorimeter (i.e. heat is directly measured), used to measure energy expenditure in humans.

Respiration Chamber

The heat given off by the subject in the chamber is directly proportional to the energy expanded.

Energy Value of Food

This may be calculated from the carbohydrate, fat and protein content of food by applying the Atwater or physiological fuel values (PFV) which are 4,9,4 Kcal respectively, to these nutrients.

Energy Value of Food

indirect method (1)

Respiration Chamber

direct method (2)

Energy Value of Food

This may also be determined from the amount of oxygen used to burn a given amount of food.

1L of oxygen =

4.825 Kcal

Energy Expenditure of Humans

may be calculated from oxygen consumption

Energy Expenditure of Humans

indirect method (2)

closed circuit

The source of oxygen is known, such as e.g., the Benedict Roth

Respiration Apparatus; suitable for measuring energy expenditure at rest.

open circuit

the source of oxygen is outsider air; e.g., the Kofranyi-Michaelis

Respirometer; exhaled air is collected in a bag and analyzed for carbon dioxide; oxygen consumption is computed from the amount of CO2 produced; suitable for measuring energy expenditure during activity

Heart rate monitoring method

This continuous monitoring heart rate offers alternative way to estimate total energy expenditure in a free living subject; based on the strong positive correlation between heart rate and oxygen consumption and therefore energy release from food energy stores.

Heart rate monitoring method

This relationship can be explained by the fact that the O2 needed to release energy from food is transported through the blood.

Heart rate monitoring method

indirect method (3)

Heart rate monitoring method

Increased oxygen consumption requires increased blood flow, powered by increase in heart rate.

Doubly-labelled water technique

This based on the fact the hydrogen atoms of body water leave the body via the usual routes of water loss with urine , sweat, saliva and as evaporated water; while the oxygen atoms of the body of the same routes but also as carbon dioxide gas.

Doubly-labelled water technique

Subtracting the hydrogen losses from the oxygen losses provides a measure of carbon dioxide fluctuation which may be converted to energy expenditure.

Doubly-labelled water technique

indirect method (4)

Respiratory Quotient (RQ)

In respiration studies, both the amount of oxygen consumed and the amount of carbon dioxide produced are often measured.

Respiratory Quotient (RQ)

RQ= Volume of CO2 expired /

Volume of O2 expired

Respiratory Quotient (RQ)

indirect method (5)

Respiratory Quotient (RQ)

Indicates whether carbohydrate, fat, or protein, or what mixtures of these nutrients are being used for energy.

Carbohydrate = 1.0

Fat = 0.7

Protein = 0.8

RQ of energy - yielding nutrients if used as sole energy source:

RQ is usually 0.82

Under normal conditions and usual diet when both carbohydrate and fat are being used for energy

Energy intake

the amount of energy eaten by individual

Energy expenditure

the amount of energy used to maintain essential metabolic processes, muscle tone, voluntary and involuntary activities, and the thermic effect of food

energy intake = energy expenditure

the individual is said to be in a state of energy balance

energy intake > energy expenditure

the individual is in negative energy balance

(-) energy balance

It means that body tissues, particularly body fat, are being broken down (catabolism) to provide the needed energy.

(-) energy balance

growth failure in children; loss of weight in adults

a) Basal thermogenesis (basal metabolism)

b) Exercise-induced thermogenesis (physical activity)

c) Diet-induced thermogenesis (thermic effect of food)

components of energy expenditure

Basal Metabolism (BM)

The basic essential metabolic processes required by the body at rest.

Basal Metabolism (BM)

Energy expanded in the maintenance of metabolic process or vital processes (involuntary activities) such as respiration, circulation and maintenance of body temperature and muscle tones.

Basal Metabolic Rate (BMR)

The amount of energy required for basal metabolic processes per unit body weight per unit time (e.g., kcal/kg/hr).

Basal Metabolic Rate (BMR)

This constitutes at least 50% of energy expenditure.

Basal Metabolic Rate (BMR)

This is measured under standard conditions of room temperature and subject is in post-absorptive state (12 to 16 hours after taking food).

1 kcal/kg body

Male Adult BMR

0.9 kcal/kg body

Female Adult BMR

Resting Metabolism (RM)

This is similar to basal metabolism, but measured under actual (not standardized) conditions & subject does not have to be in post-absorptive state but not less than 2 hours after a light meal and after resting in a supine position for more than 30 minutes.

Resting Metabolism (RM)

This includes thermic effect of food

Resting Metabolic Rate (RMR)

This is the amount of energy required for the basal metabolic processes and thermic effect of food per unit weight per unit time; also called resting energy expenditure (REE).

Resting Metabolic Rate (RMR)

This includes for digestion and absorption, it is about 10% higher than the BMR.

Resting Metabolic Rate (RMR)

This is preferred over BMR in computing total energy expenditure and or requirement since individual does not have to be in post-absorptive state and measurement can be done under actual environmental conditions.

1) Body composition

2) Body size

3) Sex

4) Age

5) Growth

6) Endocrine Secretion

7) Nutritional status

8) Pregnancy and Lactation

9) Body temperature

10) Environmental temperature climate

11) Sleep

12) Physical or Muscular activity

13)Specific Dynamic Action or Thermal Effect of Food

14) Caffeine and Smoking

Factors Affecting BMR