Nutritional Assessment

What is nutritional assessment and how can it be completed?

Nutritional assessment is a handy tool for the application of nutritional therapy. It is related to the individual’s (1) food and nutrient intake ( a diet history), (2) lifestyle, (3) medication intake, (4) social and medical history and (5) anthropometric, body composition and biochemical measurements. It includes both the screen in a grand assessment of the person’s nutritional status, the collection of data through the use of interviews, questionnaires and specially designed forms and the scientific analysis of the information obtained. These data are used to identify the nutritional status of the individual, to design the appropriate dietary therapy and to investigate the need for more significant nutritional support.

What information should be collected from a dietary history?

Taking a dietary history is a common method of evaluating food intake, and was devised by Burkein1947.Itcanbemadebytaking, through an interview, an informative dietary history of an individual or a group of people. This dietary history should provide all the data needed to evaluate the food andfluidintake.Itconsistsofa24-hour recall, a food frequency questionnaire and a three-day food record. Some of the most frequent and necessary information collected is: the usual dietary and meal plan, the number of meals, the usual meal size and the common amount of food, the usual location of eating, the consumption of ready-made meals, snacks and fast food, fluid intake, including the consumption of beverages and alcohol, possible food allergies, food preferences and the frequency of consumption.

What are the strengths and the limitations of the dietary history?

A dietary history can give the dietitian an accurate picture not only of a person’s normal food intake but also of the quality of that diet. However, the interview is a time-consuming process requiring well-educated interview-ers being able to collaborate successfully with interviewees in order both to generate accurate data about a person’s usual dietary intake and to be able to differentiate between the number and content of daily meals (daily meal plan).

What are the advantages and disadvantages of the 24-hour recall method?

The 24-hour recall is a simple method of direct nutritional assessment, which was first used by Wiehl in 1942. Using this method, it is easy to obtain the necessary information concerning the individual’s total food and fluid intake, for the previous day or previous 24 hours. It is a quantitative method and is based on the assumption that the intake described is typical of the daily food and drink intake of the individual. The advantages of this method are that it is easy, quick, to a large extent representative and does not need special equipment (e.g. scales). It does not need literacy and is less likely to alter eating behaviour, as are a latively minimal response burden.Themain disadvantages of this method are: (1) it is dependent on the memory of the individual and thus it is not advisable for individuals with decreased memory skills (older people and young children); (2) it does not provide accurate information when there is a day-to-day variation of the food intake; and (3) there is usually the tendency from the interviewees asked to declare incorrect food intake (either lower or higher than actual food intake), which may lead to statistical mistakes and unreal results (overestimation appears to be more frequent than underestimation for portion sizes). The role of a well-skilled dietitian or any other health professional involved in this method is essential in order to obtain the data accurately.

How do we select the appropriate method?

The selection of the appropriate method depends on the type of information to be collected. As there is no ideal method that could be used in all the cases and evaluations, each method addresses a different target group (e.g. different age, gender, social, educational group) or a different food or nutrient intake assessment. For the estimation of the actual nutrient intake of individuals or small groups of people for a certain period, food diaries or 24-hour recall are used. For the estimation of the mean dietary and nutrient in taking in a large population,repeated24-hour recalls or food diaries are used, while in the case of the estimation of the mean intake of a certain food item (e.g. specific type of fat, sweetener, fibre), by a small or larger population, a

Table F1 Classification of weight status by body mass index food frequency questionnaire is used instead. Finally, in the case of the evaluation of a population being in nutritional danger, repeated 24-hour recalls or a food frequency questionnaire are more commonly used. How can we calculate the body mass index and how should we use it? Is it always reliable? BMI is the most recommended classification of body weight and one of the simple stands most widely use met Horsforth estimation of body fat.Developed by the Belgian statistician Adolphe Quetelet, it can be calculated by a simple question, dividing the subject’s weight by the square of his/her height. BMI is typically expressed in either metric or imperial units and constitutes an indicator of the stores of body fat, is related to an increased danger of illness and mortality, for individuals. BMI classifiesindividuals as underweight, normal weight, overweight or obese.  Table F2  Classification of risk of diabetes (type 2), hypertension and cardiovascular disease associated with body weight. It can be also calculated in US/Customary units: BMI lb 703 / in.2, where ‘lb’ is the subject’s weight in pounds and ‘in.’ is the subject’s height in inches. Values of BMI lower than 25 are considered of normal weight. Individuals with BMI of 25–30 are considered overweight, while values over 30 present obesity. Persons with a BMI 18.5 have an increased mortality rate. It should be mentioned, though, that BMI is not directly correlated with the accumulation of body fat, and for this reason, there are exceptions (e.g. athletes, who have a very limited level of body fat and cannot be classified as overweight or obese like other adults).

Which anthropometric measurements are the most useful?

The term ‘anthropometric’ refers to comparative measurements of the body, which are used in nutritional assessments to understand human physical variation. The most useful measurements for infants, children and adolescents, which are used to assess growth and development, usually include

• length
• height
• weight
• weight-for-length
• head circumference (length is used in infants and toddlers, rather than height, because they are unable to stand).

The anthropometric measurements which are used for adults usually include

• height
• weight
• BMI
• waist/hip ratio
• percentage of body fat.

Is the waist/hip ratio a useful tool for nutritional assessment?

The measurement of circumferences of the human body, for example, the area of waist and hip, can be used in order to estimate the distribution of body fat and the danger of the development of certain diseases related to the central distribution of fat. The waist/hip ratio (WHR) is the ratio of the circumference of the waist to that of the hips and is calculated by measuring the waist circumference, just above the upper hip bone and dividing by the hip circumference at its widest part. In several, but not all observational studies, indexes of abdominal adiposities, such as the WHR and waist circumference (WC), predict coronary heart disease and strokes better than BMI, while an increased WHR is related with increased risk of stroke in women.

What are the highest healthy levels of the waist/hip ratio for men and women?

A WHR of 0.7 for women and 0.9 for men has been shown to correlate strongly with a general status of healthy, while values of WHR over 1.0 for men and over 0.8 for women are indicative of the presence of central obesity and increased risk of related diseases (associated with higher risk of diabetes and hypertension). WHRs above 0.95 for men or 0.8 for women indicate a heightened risk of heart attack (Table).

Is the measurement of wrist circumference a valuable measurement?

Wrist circumference is one of the measurements that have been proposed for the estimation of the size of the frame, which includes the width of wrist and knee and are considered valuable. However, the quotient of the height to the wrist circumference and the measurement of the width of the elbow are two of the more often used measurements of the frame’s size. The size of the frame (r) is measured through the following quotient: The classification of the frame’s size according to the guidelines of the American Dietetic Association is given in Table

Which biochemical markers are useful for nutritional evaluation?

Many different biochemical markers can reveal nutritional depletion and play an essential role in nutritional evaluation. As far as concerns the evaluation of vitamins and minerals levels in the body, this can be realised by the measurement of these or their products of metabolism, in the blood, the urine and other biological materials. Serum proteins seem to be useful markers of nutritional status.

Table F3  Classification of the size of the frame Serum albumin

The serum albumin level is an indicative marker, for the nutritional evaluation of a patient, although it has a relatively long half-life of 21 days. Patients with low serum albumin levels are in poor nutritional condition and at high risk of death.

Prealbumin

Malnourished patients, according to Subjective Global Assessment – a method of assessing nutritional status – have significantly lower levels of the real brain. Thus, determining the levels of the real brain can be a sensitive and cost-effective method of assessing the severity of illness, which can result from malnutrition in patients hoarecritica Keillor have a chronic disease and may allow for earlier recognition and intervention for hunger.

Serum creatinine

This protein is used as a nutritional marker, because of its relation to muscle mass.Meas using serum creatinine is a simple test, and it is the most commonly used indicator of renal function.

Serum transferrin

This is an iron-transport protein, which serves as a sensitive marker of total nutrition status and more specifically as a marker of iron deficiency. Serum transferrin receptor (sTfR) level is a new specific and sensitive indicator of tissue iron status and iron deficiency.

How can special nutritional requirements be identified?

Nutritional requirements are determined by a wide variety of factors. In order to identify special nutritional requirements and determine the extent to which the individual’s nutritional needs are covered, specific parameters and methods are used, which can provide all of the necessary data.The nutritional requirements assessment includes clinical assessment physical assessment biochemical/haematological assessment anthropometric and body composition assessment current dietary assessment. Many specialised methods are used by clinical dietitians for this purpose. Subjective Global Assessment (SGA) is one of the most popular and effective methods for the assessment of nutritional status and special nutritional needs.SGA class ificationisa comprehensive assessment technique and a valid screening tool for the prevention and treatment of, especially, malnutrition or undernutrition, in various patient populations.

How can we estimate protein requirements?

Protein is one of the main macronutrients that are essential for life and growth and vital for the structure and the metabolism of the human body. It is continuously broken down and synthesised (the homeostatic mechanism is known as protein turnover), but it cannot be stored, and thus there is a daily minimum requirement intake to maintain the body’s structure and function throughout life. In adults and on a daily basis, approximately 200–300g of protein or 3–4g protein/kg body weight is turned over. The protein contains nitrogen, and the daily protein requirements are related to the total amount needed to maintain nitrogen equilibrium and cover losses. A general estimation of the protein requirements is based on the current RNIs and RDAs for protein, which is, for the average adult, 0.75–0.8g/kg of body weight per day, while a more accurate estimation can be made by measuring the nitrogen excretion and total losses (via urine, faeces, fistulae or other losses).

How can we estimate carbohydrate requirements?

Carbohydrate is the main fuel for the human body and the most important dietary energy source, providing approximately 3.8kcal/g. The total carbohydrate requirements are usually expressed as a percentage (e.g. 45–60% for adults) of the total energy intake, according to the dietary reference values (DRVs) for the main nutrients, from which 39% should derive from starches, milk sugars and intrinsic sugars and not more than 11% from non-milk extrinsic sugars. At the same time, there are general recommendations for carbohydrate intake, in grams. Thus, the minimum daily recommendation for carbohydrate is 100g, in order to provide enough energy and avoid protein break-down, and the maximum intake is approximately 400g for the average adult.

How can we estimate fluid requirements?

Fluid requirements vary considerably between individuals and are influenced by various factors, related to the individual’s age, gender, level of physical activity, type of diet, the environmental temperature and the climate, the individual’s total fluid intake (from foods, water and beverages) and fluid output (kidney losses, respiratory, skin and gastrointestinal losses) and the general state of the individual’s health. Individuals should take no less than some fluids that cover the total losses and no more than the amount that can be excreted by the kidney function. It is recommended that the fluid intake should be at least 500–750ml greater than urinary losses, but it should be even greater in cases of high temperatures or the presence of burn or pyrexia or the case of any other reason of higher-than-normal losses. Generally and under normal circumstances, the fluid requirements can be estimated: children: 1.5ml/kg adults: 1ml/kg or 30–35ml/kg body weight.

What are the biochemical markers that determine dehydration?

Dehydration is a fluid imbalance caused by inadequate intake or excessive losses. There are different biochemical markers that can identify and reveal the presence of dehydration. These markers are: urea/creatinine ration, which should be 0.15 elevated levels of plasma sodium urine colour or specific urine gravity serum osmolarity.

Which categories of people are in danger of dehydration?

Hydration status,fluidbalanceandsufficientfluiddepletionareimportantfac-tors for the management to general health, and forth management to certain medical conditions and for the maintenance of physiological homoeostasis. Dehydration is linked to constipation, medication toxicity, renal failure, urinary tract infections, elevated body temperature, dizziness and general weakness. Those at risk of dehydration are: infants and young children, owing to poor intake or increased gastrointestinal losses older people or patients,owingtolowfluidintake, blunted thirst response or poor food intake (anorexia, depression) people with eating and/or swallowing difficulties people with undiagnosed (or uncontrolled) diabetes mellitus and burns patients patients receiving diuretic drugs and laxatives or people with the symptoms of diarrhoea and/or vomiting patients suffering from pyrexia (mostly older) people with a physical immobility.