Nutrition

Nutritional Status Assessment

Objectives
By the end of this lecture you be able to: Understand the related definitions. Remember how to evaluate the nutritional status; anthropometric measurements, dietary assessment; their types, uses, advantages &limitations.

Nutritional Status Assessment: The health condition of an individual is influenced by food consumption & utilization of the nutrients this require evaluation of nutritional status. It is essential for the diagnosis of different diseases It is the first step in the development of satisfactory plan for the nutritional care of individual or community (preventive or treatment of acute or chronic diseases).

The evaluation of nutritional status: includes: 1-Anthropometric measurements. 2-Dietary evaluation. 3-Clinical evaluation. 4-Lab. assessment. Each component has: its important strengths &limitations no single technique will provide a thorough assessment of nutritional status.


I-Anthropometric Measurements: It is the simplest most quantitative measure, by using the measurements of the body thickness to estimate fat & lean tissue mass. It is widely used in clinical practice. It can be expressed by Z-score (is the SD of the values from the median value of reference population). Uses: 1-Monitoring of normal growth. 2-Detecting nutritional health in well-nourished individual. 3-Detecting nutritional inadequacies or excess.

Advantages: It is simple safe inexpensive can be applied at the bed side. Limitations: It can detect only those nutrients abnormalities that result in measurable changes in body size or proportion.

The used measurements:*Weight.*Length (infants & young children) or height.*Head circumference (infant &young children).* Mid upper arm circumference.* Skin–fold thickness: triceps, supra-iliac, sub scapular skin–fold thickness.#Body size assessed by weight & SFT is closely related to food intake.

A-Body Wt.: It is convenient useful indicator for the nutritional status. Poorly nourished mother may deliver LBW infant & this child is at risk of low wt./age . *The wt. should be measured with minimal cloths by using: *a lever balance- type of scale. *Reference tables provide standard wt. for Ht., age & sex. *If the patient has edema at the time of weighing, the wt. may be falsely high.



B-Length & Height: In infants & toddlers (<2y), the length is measured in supine position with a fixed headboard & a sliding foot board.


In older children & adults the height is measured by using a horizontal arm that moves vertically on a calibrated scale. The person should be: ** erect ** without shoes ** heels together ** against a straight surface with the head level erect.

Field type of stadiometer

BMI: Is the ratio of weight in kilogram (with minimal clothing) to height (without shoes) in meter square. For both male &female. -BMI 20-24.9 is normal or desirable weight range -BMI 25-29.9 is low relative risk (over weight). -BMI 30-40 is moderate risk (moderate obesity) = grade I&II -BMI > 40 is high risk (morbid obesity)=grade III

C-Head circumference: It is a good index of brain growth( usually used for infants &children) as a screening for microcephaly ¯ocephaly ( standard procedure in pediatric practice). D-Mid- Arm muscle circumference( MAC): It can serve as a general index of nutritional status (reflect both caloric adequacy &muscle mass).

MAC is measured at the midpoint of the left upper arm by fiberglass flexible tape field work type called Shaker’s strip The value can be compared with reference graphs available for both sexes & all ages.**In case of PEM& negative N.B. include muscle wasting decrease muscle circumference.

Shaker strip for measuring MAC

If the color is red (MUAC below 11 cm), then the child is severely malnourished and need to immediately be taken to the nearest qualified health worker, health facility or hospital for assessment, treatment and follow up.
If the color is yellow (MUAC below 12.5 cm), then the child is moderately malnourished and needs assessment and supplementary foods (additional enriched food). If UNIMIX/CSB is not available, follow the guidelines on good complementary food listed fact sheet “The best foods for children under 5” years Green color (MUAC above 12.5 cm) means that the child is healthy and not malnourished. This child should continue to eat the good foods listed in fact sheet “The best foods for children under 5”

E–Skin- fold thickness (SFT): The skin fold consists of two layers of subcut. fat (without muscle or tendon) Measured by special calipers called Lange SF caliper (SFT measured for triceps, biceps, sub scapular &supra pubic).**A fold of skin in the posterior aspect of non dominant arm midway between shoulder & elbow in a relaxed position is grasped gently &pulled a way from the underlying muscle.**Average of 3 readings taken **compared to reference standard tables to assess the fat thickness. It is differ according to the age ( increase with the age), sex & ethnic origin.



Skinfold Calipers Measure Thickness of Subcutaneous Fat in Millimeters
Courtesy Dorice Czajika-Narins, PhD


II-Dietary assessment: Describe the dietary intake background which help to explain any observed clinical or biochemical abnormalities. 1-Twenty- four hour dietary recall : (one of the most common methods of dietary assessment) Advantages: it is easy require little effort from the patient to recall the intake.


Limitations: 1-The consumption in a single 24h. period may be not representative of current weekly or monthly intake. 2-Inaccurate data due to faulty memory 3-Quantitative errors in assessing how much has been eaten. 2-One-week dietary record : All foods & beverages ingested recorded with approximate quantities (assumptions of portion size) & actual time of consumption.

Advantages: more accurate used for consumption patterns which allow the medical professional to identify deficiencies, imbalances or excesses of nutrient intake. Limitations: Feedback is difficult Difficult to find cooperative subjects. 3-Weighed inventory: The subjects weigh & record all food prepared & waste food composition tables are used to estimate the nutrient intake from the records. Advantage: It does not rely on assumption of portion size.


4-Food frequency: Printed questionnaires are used the subjects or interviewer tick the category that approximates to their usual consumption of a list of foods. eg. never eaten, eaten once a month , once a week, daily intake. Used to assessing food groups. It is used usually in large surveys.


III- Clinical evaluation: General malnutrition may result from; a-Primary factors (deficient dietary intake) take dietary history. b-Secondary factors (defect in nutrients utilization), e.g. GI disorders, metabolic disorders take clinical history. Prolong malnutrition may cause the following sequence of events; 1-A general decrease in tissue levels of deficient nutrients. 2-A biochemical lesion such as altered activity of the enzyme dependent on a specific nutrient &/or accumulation of its metabolite by time. 3-Anatomical lesion. 4-Finally cellular disease.

Many of clinical S&S of malnutrition appear later (after weeks or months), s.t. there is sub clinical or marginal malnutrition but still the clinical examination provides impression of nutritional health. A-Medical History: Like history of chronic illness; *wt. loss or wt. gain; the physician can detect nutritional problem or assess the likelihood of developing nutritional defect in the future (strong family history of heart dis. check s. lipid level, & encourage the patient to decrease B.W.). *Social history; socioeconomic status, cultural & religious beliefs, housing situation,& social isolation. *Medication & supplements history.


B-Physical Examination: The physician looks for physical S&S (from nutritional point of view) but require confirmation of dietary data&biochemical testing. Physical appearance: pallor, emaciation &hair changes indicate long term energy deficit, loose dentures & loose clothes indicate recent weight loss, xanthoma or corneal arcus in some types of hyperlipidemia. Edema: following protein depletion& or V.B1 deficiency. Breathlessness: result from anemia.


Taste abnormality; Zn deficiency (also it is decrease with the age, drugs, smoking). Dermatitis; due to Zn def., E.F.A. def., V.B def. Mood changes; apathy & depression, patient with eating disorders& under nutrition. Obesity, wasting , can be observed easily. Special attention is given to the areas where signs of nutritional def. appears; hair, eyes, mouth, mucous membrane, tongue, teeth, thyroid, skin, skeleton, tendon reflexes, &neuromuscular excitability provide clues of presence or absence of nutritional defects.

IV- Laboratory Assessments: It can identify specific nutritional related abnormalities, e.g. anemia, (iron def.), protein def., biochemical tests, provide the 1st indication of nutritional abnormalities before clinical anthropometric changes occur. *Protein status: -In marasmus patient (caloric deprived) normal s.protein. -In Kwashiorkor patient (protein deprived) dec. s. prot. with normal MAC. *Vitamin& mineral status: assess the circulatory level (deficiency must be prolonged before blood level are affected).