Nutrition 5

ThiQar college of MedicineFamily & Community medicine dept.

Nutrition Lecture 5/ onlineThird stage by: Dr. Muslim N. SaeedApril 29th ,2021

Nutritional Assessment

Goals of nutritional assessment
1) To identify the presence and type of malnutrition.
2) To define health-threatening obesity.
3) To advise for suitable diets as prophylaxis against disease later in life.

Nutritional assessment includes the following:

• Clinical history.
• Physical examination.
• Screening tools.
• Anthropometric measures.
• Laboratory assessment.
• Measuring body composition.

1.Clinical history

• The timing and amount of weight loss:recent unintended weight loss of > 5% of usual weight should prompt efforts to diagnose the underlying disorder or social circumstance.
• Medical illnesses, e.g. DM, liver cirrhosis.
• Medications.
• Gastrointestinal symptoms: anorexia, nausea, vomiting, dysphagia, abdominal pain, diarrhoea.
• Diet habits: Eating fewer than two meals per day, following a prescribed diet, Food allergy or intolerance, Alcohol consumption, dietary supplement intake including vitamins, minerals and herbs, dental status.
• Social habits: eating alone, needing assistance in self-care.
• Economic status: having enough money for food.
• Mental status: especially the presence of depressive symptoms.


2. Physical examination

-It utilizes a number of physical signs,(specific & non specific), that are known to be associated with malnutrition and deficiency of vitamins & micronutrients.
-General clinical examination, with special attention to organs like hair, angles of the mouth, gums, nails, skin, eyes, tongue, muscles, bones, & thyroid gland.
-The physical findings of deficiency syndromes of vitamins, essential fatty acids, and trace metals.

-Only marasmus and cachexia syndromes are evident at examination.

-Loss of subcutaneous fat and skeletal muscle is manifested by sunken temples, thin extremities, wasting of the muscles of the hand, and, rarely, edema.
-Kwashiorkor in children is characterized by severe edema and a potbelly appearance from hepatomegaly and ascites.
-Detection of relevant signs helps in establishing the nutritional diagnosis.

3. Screening tools

- Investigators have made numerous attempts to combine various components of nutritional assessment, including clinical history, physical examination, anthropometry, and serum proteins, into a single score.
- Some of the more widely used tools include the following:
1) Subjective global assessment (SGA).
2) Nutritional risk index.
3) Mini-nutritional assessment.
4) Malnutrition universal screening tool.

Subjective global assessment(SGA)- SGA is highly predictive ofnutrition associated complications.1) Identifying malnutrition.2) Distinguishing malnutrition from a disease state.3) Predicting outcome.4) Identifying patients in whom nutritional therapy can alter outcome.

4. Anthropometric measures

1) Body weight
- Is a useful element in the physical examination, it is expressed as a relative value to evaluate the patient in relation to the healthy population.
- Weight and height are easily obtained, and standards for comparison have been established.
2) Body mass index (BMI)
- BMI has two valuable attributes:
• It is relatively independent of height.
• The same standards apply to male and female patients.
- BMI correlated with outcome better than weight and height.

Category

BMI Kg/m2

From

To
Severe underweight
15
15.9
Underweight
16
18.4
Normal (healthy weight)
18.5
24.9
Overweight
25
29.9
Obesity Class I (Moderately obese)
30
34.9
Obesity Class II (Severely obese)
35
39.9
Obesity Class III (Very severely obese)
40 and above


3) Upper arm anthropometry
- Triceps skinfold thickness (TSF) is the most practical technique to estimate body fat.
- Generally, a value lower than the 5th percentile is used to define abnormality.
- The principal value of the TSF measurement is to determine the arm muscle circumference (AMC) or arm muscle area.





- The AMC is a specific measure of protein-energy malnutrition if the 5th or 10th percentile is chosen as the cutoff point, and it is particularly valuable in patients in edematous states and in amputees, in whom weights are inaccurate or insensitive.

4) Waist and hip circumference

a) Waist circumference
- It is measured at the level of the umbilicus.
- It gives and indication of the degree of abdominal obesity.
b) Hip circumference
It is measured at the level of the greater trochanter.
c) Waist : hip ratio WHR
- To assess body fat distribution whether android (apple shaped, central, visceral, abdominal) obesity or gynecoid (pear shaped) obesity.


Waist : hip ratio (WHR) interpretation

5. Laboratory assessment

A) Serum proteins
1) Albumin
- Normal value (3.5 – 5.5 g/dl).
- It is the traditional standard for nutritional assessment.
It is used to separate the two principal forms of PEM.
Hypoalbuminemia is a strong predictor of risk for morbidity and mortality.
Serum Albumin increases in:
• Dehydration.
• Marasmus.
• Blood transfusions.
• Exogenous albumin.


Serum Albumin decrease in :
• Kwashiorkor
• Zinc deficiency
• Pregnancy.
• Nephrotic syndrome
• Burns
• Cancer
• Corticosteroid therapy

2) Other proteins (pre-albumin, transferrin, retinol binding protein)

These proteins do not reliably identify the presence and severity of the systemic inflammatory response any better than albumin, but they reflect the nutritional response more quickly when inflammation decreases.

* Transferrin:

Normal value (204 – 360 mg/dl).

B) 24 hour urinary creatinine

- Normally 500 – 1200 mg/day.
- Low value indicates muscle wasting.

C) Creatinine – height index (CHI)

It is determined by measuring 24 hour urinary creatinine excretion in relation to the patients height.
It indicates protein depletion.

D) Assessment of mineral deficiency

Mineral
Symptoms or signs of deficiency
Test
Calcium
Osteomalacia, tetany, arrhythmia
- Serum ionized Ca
- DEXA scan
Magnesium
Weakness, twitching, tetany,
arrhythmia, hypocalcaemia
- Serum Mg
- Urinary Mg
Iron
Microcytic hypochromic anaemia
- Serum Fe
- TIBC.
Zinc
Growth retardation, delayed sexual
maturation, alopecia, diarrhoea, mental status changes
- Plasma Zn
- Leucocyte Zn
Iodine
Hypothyroidism, goiter
- Urinary Iodine
-TSH
Phosphorous
Weakness, fatigue, haemolysis,
respiratory muscle insufficiency
- Plasma P


E) Assessment of vitamin deficiency: by measuring serum levels of vitamins and other investigations. (clinical features mentioned in lecture 3).
6) Measuring body composition:
• Anthropometry (weight, BMI, skinfold thickness, waist circumference).
• Underwater weighing.
• Bioelectrical impedance analysis (BIA).
• Dual energy X-ray absorptiometry (DEXA).
• CT scan, MRI.

End