Nutrition 4

• Malnutrition


  All deviations from adequate nutrition, including undernutrition (and overnutrition) resulting from inadequacy of food (or excess of food) relative to need (respectively)

  
• Malnutrition


  Encompasses specific deficiencies (or excesses) of essential nutrients such as vitamins and minerals

  
• Malnutrition


  Conditions such as obesity, although not the result of inadequacy of food, also constitute malnutrition

  
• Undernutrition


  The outcome of insufficient food of whatever kind caused primarily by an inadequate intake of dietary or food energy, whether or not any specific nutrient deficiency, such as iron deficiency anaemia, is present
• Undernourishment


  When food intake is continuously insufficient to meet the dietary energy requirements
• Undernutrition


  The result or outcome of undernourishment, poor absorption and/or poor biological use of nutrients consumed
• Assessment of undernutrition


  • Nutritional intake assessment
  • Nutritional status assessment

  
• Nutritional intake assessment


  Estimates the amount of food a person is eating and can be used to assess adequacy of the quantity of dietary energy (and protein) supply

  
• Nutritional status assessment


  Assesses the nutritional status of the individual or a representative sample of individuals within a population by measuring anthropometric, biochemical or physiological (functional) characteristics to determine whether the individual is well-nourished or undernourished
• A hierarchical model of the causes of undernutrition emphasizes the importance of repeated infectious episodes and poor care and neglect as determinants of undernutrition, in addition to the lack of adequate food

  
• Anthropometry


  The most frequently used method to assess the nutritional status of individuals or population groups. Measurements of nutritional anthropometry are based on growth in children and body weight changes in adults
• Benefits of nutritional status assessment

  • Immediate treatment
  • Development of healthcare programmes to meet community needs
  • Assessment of effectiveness of programmes
• Methods of nutritional assessment

  • Direct methods
  • Indirect methods
• Indirect methods


  Use community health indices that reflects nutritional influences
• Indirect methods


  • Ecological variables including crop production
  • Economic factors e.g. per capita income, population density and social habits
  • Vital health statistics particularly infant under 5 mortality and fertility index
• Direct methods


  • Anthropometric methods
  • Biochemical methods
  • Clinical methods
  • Dietary evaluation methods
• Anthropometric measurements


  Measurements of the variations of the physical dimensions and the gross composition of the human body at different age levels and degrees of nutrition
• Anthropometric measurements


  • Height/age ratio and weight/height
  • Mid-upper arm circumference
  • Head circumference
  • Skin fold thickness
  • BMI
  • Waist/hip ratio

  
• Advantages of nutritional anthropometry

  • Methods are precise and accurate, provided standardized techniques are used
  • Procedures use simple, safe and non-invasive techniques
  • Equipment required is inexpensive, portable and durable, and can be made or purchased locally
  • Relatively unskilled personnel can perform measurement procedures
  • Information is generated on past nutritional history
  • Methods can be used to quantify the degree of undernutrition (or overnutrition) and provide a continuum of assessment from under-to overnutrition
  • Methods are suitable for large sample sizes such as representative population samples
  • Methods can be used to monitor and evaluate changes in nutritional status over time, seasons, generations, etc.
  • Methods can be adopted to develop screening tests in situations such as nutrition emergencies to identify those at high risk
• Limitations of nutritional anthropometry

  • The relative insensitivity to detect changes in nutritional status following inadequacy of food over short periods of time
  • The inability to distinguish the effect of specific nutrient deficiencies (e.g. zinc deficiency) that affect growth in children from that due to inadequacy of food in general
  • The inability to pinpoint the principal causality of undernutrition, as the poor nutritional status may be the result of factors such as repeated insults owing to infections and poor care in children
  • The relative higher costs and organization required to obtain representative and quality data for the purpose of estimating numbers of undernourished

  
• Height/age ratio


  Appropriate height for given age

  
• Mid upper arm circumference

  Measured half-way between the acromion process of the scapula and the tip of the elbow (ulnar) with the arm hanging vertically and forearm supinated. Provides estimate of arm muscle area: reflects skeletal protein reserves
• Head circumference


  The measurement of the head along the supra orbital ridge (forehead) anteriorly and occipital prominence (the prominent area on the back part of the head). Useful in assessing chronic nutritional problems in children under two years old as the brain grows faster during the first two years of life
• Skin fold


  A skinfold caliper is used to assess the skinfold thickness, so that a prediction of the total amount of body fat can be made
• Triceps skin fold


  The most reliable one to assess, because oedema is not often seen in the upper arm. Measurements are less reliable in elderly people, due to their weak skin and muscles. Its thickness gives information about the fat reserves of the body, whereas the calculated muscle mass gives information about the protein reserves
• Body Mass Index (BMI)

  A measure for indicating nutritional status in adults. It is defined as a person's weight in kilograms divided by the square of the person's height in metres (kg/m2). Developed as a risk indicator of disease; as BMI increases, so does the risk for some diseases

  
• Waist/hip ratio


  A quick measure of fat distribution that may help indicate a person's overall health. People who carry more weight around their middle than their hips may be at a higher risk of developing certain health conditions
• Excessive body fat


  • Has an impact on disease and death
  • Is reasonably well related to adiposity

  
• BMI


  A risk indicator of disease; as BMI increases, so does the risk for some diseases
• Common conditions related to overweight and obesity

  • Premature death
  • Cardiovascular diseases
  • High blood pressure
  • Osteoarthritis
  • Some cancers
  • Diabetes
• BMI for children and adolescents


  • Calculated as for adults and then compared with z-scores or percentiles
  • Cut-off values that determine nutritional status are gender- and age-specific

  
• Waist-to-hip ratio (WHR)


  • A quick measure of fat distribution that may help indicate a person's overall health
  • People who carry more weight around their middle than their hips may be at a higher risk of developing certain health conditions
• According to the World Health Organization (WHO), having a WHR of over 1.0 may increase the risk of developing conditions that relate to being overweight, including heart disease and type 2 diabetes
• This may be the case even if other measures of being overweight, such as body mass index (BMI) are in normal range

  
• Healthy WHR


  • 0.85 or less for women
  • 0.9 or less for men
• Visceral Fat (VF)


  • The underlying culprit for cardiovascular diseases, type 2 diabetes, breast cancer, etc.
  • Can be estimated using expensive instruments like Bio Impedance Analyzer (BIA), DEXA scanner, etc.
  • Measurement of Waist-Hip Ratio (WHR) can be used as a proxy for VF
• Biochemical methods of assessment

  • Measuring a nutrient or its metabolite in the blood, faeces, urine or other tissues
  • Levels of nutrients and their metabolites in body tissues and fluids are a consequence of the variations in quantity and nutrient composition of food consumed and utilized by the body
  • Biochemical tests are sensitive to even small changes in nutritional intake and therefore, provide the earliest indication to malnutrition
  • Biochemical assessment also confirms clinical diagnosis of nutritional status and/ or risk for a disease

  
• Commonly used biochemical tests

  • Haemoglobin
  • HbA1c Glycation test
  • Urine analysis (for albumin and sugar)
  • Blood levels of lipoproteins and triglycerides
• Advantages of biochemical methods

  • Able to detect early changes in body metabolism and nutrition before the appearance of clinical signs
  • Accurate and reproducible
  • Useful to validate data obtained from dietary methods

  
• Disadvantages of biochemical methods

  • Expensive
  • Time consuming
  • Needs trained personnel and facilities