Chapter 3.1
             Biochemical Parameters of Nutrition
             Emine M.Inelmen,Giuseppe Sergi
             Introduction                                              also been included under the umbrella of ‘under-
                                                                       nutrition’ [3, 4]. The vulnerable groups for under-
             Nutrition is an important factor in the aetiology         nutrition are infants, children, pregnant women,
             and management of several major causes of death           low-income families, hospitalised patients, cancer
             and disability. The nutritional status of a person is     patients and ageing adults.
             the result of a balance between the intake and the            Aetiologically,malnutrition should be regarded
             requirement of nutrients. Optimal nutritional sta-        as a geriatric syndrome, because of the multiple
             tus is achieved when sufficient nutrients are con-        factors, disease- and age-related risk factors, that
             sumed to support day-to-day body needs.This sta-          disturb the balance between nutritional need and
             tus promotes growth and development, maintains            intake [5].Malnutrition or nutritional deficiency is
             general health, support activities of daily living,       defined as a continuum starting with inadequate
             and assists in protection from diseases. Several          food intake, followed by decreased anthropometri-
             variables can influence the intake of food: eco-          cal and biochemical values. The diagnosis of mal-
             nomical, emotional, developmental and cultural            nutrition is generally based on objective measure-
             factors, dietary patterns, unbalanced self-imposed        ments of nutritional status, including assessments
             diets, anorexia, bulimia, etc. The intake of food         of oral energy intake, weight loss, anthropometric
             also varies in relation to many physiological situa-      data, cell-mediated immunity, biochemical param-
             tions, such as growth, pregnancy, breast-feeding          eters and body composition analysis [6].Although
             and physical activity.Dysphagia,dyspepsia,malab-          these indicators are epidemiologically useful,there
             sorption, loss of nutrients (vomit, diarrhoea,            is no gold standard; thus, nutritional evaluation
             wounds, fistulas, drainage, etc.), alterations in         tends to be overlooked [7–9]. Body weight, for
             metabolic and nutritional requirements, and drug          example, can be inaccurate if oedema, ascites or
             interactions can be present in different pathologi-       fluid balance derangements are present, resulting
             cal situations.                                           in falsely high body mass index [10]. Hence, atten-
                 Malnutrition can be the result of nutrition in        tion should be turned to combinations of different
             excess or in defect. Hyper-nutrition or hypo-nutri-       measurements to increase sensitivity and specifici-
             tion could be more appropriate terms. There are           ty [11]. Well-known clinical problems such as
             many definitions of the term malnutrition, which          dehydration and dysphagia are highly prevalent in
             vary significantly; this is one of the reasons for the    patients suffering from malnutrition, and initial
             heterogeneity in the epidemiological and clinical         screening should address these problems as well
             data [1].Hypo-nutrition or under-nutrition occurs         [12,13].
             when nutritional reserves are depleted and/or
             when nutrient intake is inadequate to meet day-to-
             day needs.It has been defined as a nutritional dis-       Nutritional Assessment in the Elderly
             order status resulting from reduced nutrient intake
             or impaired metabolism [2].It is used to describe a       The percentage of elderly persons is rising in most
             broad spectrum of clinical conditions ranging             countries around the world [14]. Ideally, people
             from mild to very severe. The state of impending          should survive to an advanced age, keeping their
             under-nutrition, or increased nutritional risk, has       vigour and functional independence,and morbidi-
      60     Emine M.Inelmen,Giuseppe Sergi 
             ty and disability should be confined to a relatively     ence values of the anthropometric measures are
             short period before death [15, 16]. Hence, a major       not always age-adjusted [9].Anyway, when malnu-
             challenge today is how we can improve overall            trition has been estimated using a combination of
             health and quality of life at older ages; if the aver-   at least one anthropometrical and one biochemical
             age age of onset of ill health remains unchanged,        variable,the sensitivity increases [27,28].
             an increased life span would mean for an individ-           The essential part of nutritional assessment in
             ual more years of ill health before death [17]. In       the elderly is an accurate medical history and a clin-
             fact, in an ageing population there are increased        ical evaluation. The medical history has to evaluate
             chronic disabilities and diseases [18], which are        particularly the dietary intake (the techniques are
             linked with loss of autonomy and health risks [14].      given below). It is important to look for the pres-
             So, it is important to study the factors that modu-      ence of acute or chronic diseases,infections,trauma
             late ageing; among these factors nutrition seems to      or stress in order to evaluate an increase of dietary
             have a very important role in health status and          requirements of the patient. Obtaining an accurate
             quality of life of elderly people [19]. Although the     medical history from an older person can be chal-
             available surveys show that healthy elderly people       lenging. Memory loss, cognitive decline and their
             generally have a good nutritional status, there is       consequences can limit its accuracy. Obtaining per-
             no doubt that the older population is at risk of         tinent data from the caregiver and from medical
             malnutrition [20], and that the nutritional needs        records is often necessary. The aim of the clinical
             and problems of this group differ from those of          evaluation is also to identify the signs of malnutri-
             their younger cohorts.                                   tion,which are given in Table 1.
                 Physical activity decreases with age and results        Another essential part of the nutritional
             in an overall lower caloric intake [21].                 assessment is the measurement of anthropometri-
             Furthermore, elderly persons may change their            cal parameters. These parameters are simple and
             eating habits because of health, social, or financial    not invasive: a meter and a plicometer allow the
             reasons [22].Almost half of the elderly population       necessary information to be obtained for an ade-
             is likely to experience olfactory dysfunction [23].It    quate nutritional evaluation.
             is widely assumed that taste and smell dysfunction          The biochemical parameters available for the
             adversely influence food intake, nutrition status,       nutritional situation have increased recently.
             and the occurrence of certain chronic diseases,          Unfortunately,most of these indexes are expensive
             confirmed by Schiffman [24].The loss of sight and        and not available in all laboratories. Besides, the
             hearing, or the presence of osteoarthritis affecting     results can often be influenced by factors that are
             mobility, may decrease the elderly person’s ability      independent from the nutritional condition of the
             to purchase and prepare food [25].                       patient. Hence, the basal parameters are still now
                 Nutritional assessment allows us to specify the      essential for the nutritional status of a person.
             nutritional needs and body reserves, as well as the         Therefore,nutritional assessment becomes cru-
             metabolic and immunological functions; it is             cial in the elderly population as progressive under-
             aimed at defining if the patient is well nourished,      nutrition occurs,often without being diagnosed.
             slightly or severely malnourished and if the aeti-
             ologies of the existing malnutrition will disappear,
             increase or decrease [26]. It consists of many dif-      Dietary Intake
             ferent tests: clinical, biochemical and anthropo-
             metric [9]. However, objective markers of nutri-         There are several difficulties in selecting a sample
             tional assessment often do not reflect physiologi-       of elderly people for a nutritional study. Some
             cal, physical, cognitive and emotional function [9].     authors [29] suggest the selection of ‘healthy’ eld-
             Moreover, nutritional assessment using objective         erly. Even if it is possible to obtain an almost
             markers is less reliable in the older subject because    homogeneous group, this is not a ‘real’ sample of
             metabolic changes, among others, affect some of          an elderly population, which is, on the contrary,
             the routine biochemical tests results,and the refer-     characterised by a high heterogeneity of subjects:
                                                                                                                     3.1 Biochemical Parameters of Nutrition      61
                Table 1.Clinical signs in malnutrition
                Hair                                    Thinness,sparseness,easy pluckability
                Face                                    Diffuse depigmentation,nasolabial seborrhea
                Eyes                                    Conjunctival xerosis,corneal
                                                        xerosis,keratomalacia,blepharitis
                Lips                                    Angular stomatitis,angular,scars,cheilosis
                Tongue                                  Magenta tongue,glossitis
                Gums                                    Spongy,bleeding
                Glands                                  Thyroid enlarged,parotid enlarged
                Skin                                    Xerosis,follicular hyperkeratosis,petechiae,ecchymoses,dermatosis
                Nails                                   Koilonychia
                Subcutaneous tissue                     Oedema
                Muscular and skeletral systems          Muscle wasting,osteomalacia
                Internal systems                        Hepatomegaly,listless,apathetic,mental confusion,irritability,sensory loss,
                                                        motor weakness,loss of balance
                Cardiovascular                          Cardiac enlargement,tachicardia
                self-sufficient, not self-sufficient and institution-                        In spite of their limitations, dietary surveys are
                alised [30]. Besides, nutritional examination in a                       the main tool for assessing nutritional habits,
                selected healthy elderly population would not                            establishing food policies, and creating awareness
                show variations in dietary patterns; in fact, they                       of nutritional needs [31]. Although biochemical
                try to maintain the food habits because of a reduc-                      tests have been widely accepted as an objective
                tion of the adaptation capacity with age [31].                           assessment of nutritional status,especially of mar-
                Elderly people’s associations with food are more                         ginal states, malnutrition and suboptimal nutri-
                emotional than those of younger adults; for some,                        tion can be adequately understood only in the
                food intake is the main event in the course of the                       light of dietary data on food consumption, meal
                day, often providing the only possibility of social                      patterns and methods of preparation [31]. Any
                contact [31]. The elderly have repeatedly been told                      method used for dietary surveys in the adult popu-
                that good food means good health [31].So,the eld-                        lation can, theoretically, be used for surveys in the
                erly may eat simply because they know they have                          elderly [31].
                to, even if they do not feel like eating, or they may
                eat because the food is delivered and throwing it
                away would be wasteful [32].                                             Survey Techniques for Assessment of Food
                     Another question is the continuing debate about                     Intake
                the use of reference parameters in nutritional stud-
                ies in the elderly. In fact, the value of dietary intake                 Dietary Records and Diaries
                data as an indicator of health status in an elderly                      The most widely used technique for the assessment
                population is debatable [32]. In a population with                       of food intake is keeping a record of food con-
                an increased number of physical and mental dis-                          sumption [31]. Ideally, food should be weighed
                abilities like the elderly, dietary assessment meth-                     before and after preparation, records kept during
                ods might be adapted or different methodologies                          the meal, and leftovers weighed again [31]. This
                might be developed [19]. An independent measure                          technique produces data that can be expressed in
                of the reliability of reported energy can be obtained                    quantitative terms,be converted into nutrients,and
                by calculating the ratio of energy intake to the rest-                   serve as the basis of clinical and biochemical
                ing metabolic rate (RMR) [33].                                           research [31].Investigators working with the elder-
      62     Emine M.Inelmen,Giuseppe Sergi 
             ly prefer the record system even if the food intake     items [38] and can be administered by a healthcare
             can be influenced by this process to such a degree      professional in less than 15 minutes. It involves a
             that the subject’s original food pattern can be         general assessment of health,a dietary assessment,
             changed.It is better to record dietary intake over a    anthropometric measurements, and a subjective
             period of three non-consecutive days with a ratio       self-assessment by the patient (Table 2). The
             of 5/2 between working days and holidays [34].          results of the MNA test classify the patient as well
                                                                     nourished, at risk for malnutrition, or malnour-
             Diet Histories                                          ished. The MNA test was shown to be 92–98%
                                                                     accurate.It is a simple,non-invasive,well-validated
             Several models of diet histories have been devel-       screening tool for malnutrition in elderly persons.
             oped,but the most common are the 24-h diet recall
             and the modified dietary history.
                The 24-h diet recall is characterised by the         Dietary Requirements for the Elderly
             evaluation of the quantity and quality of the food
             consumed in 24 hours before the interview. It is a      Nutrition may act in different ways: first, lifestyle
             simple method and is particularly indicated for         and nutritional habits of adulthood may con-
             wide samples [34] but requires a highly skilled         tribute to the age-related loss of tissue function;
             interviewer.                                            second,chronic degenerative diseases,such as ath-
                The modified dietary history is a classic            erosclerosis and cancer,appear to be influenced by
             method for evaluating the ‘usual diet’, that is the     nutrition; finally, since elderly people eat less, the
             diet for at least 6–12 months before the interview.     intake of some nutrients may fall below the recom-
             This method was validated in the elderly with the       mended dietary allowances (RDA) [39]. But, until
             record for 3 days, in which the participant is asked    now,most of the nutritional recommendations for
             to note all the foods and beverages consumed            the elderly have been derived by extrapolation
             daily; illiterate or handicapped subjects are helped    from data of younger adults [32, 39]. The contro-
             by a relative or a friend [35]. A sufficient concor-    versial point is the choice of two-thirds of the RDA
             dance between the two methods emerged from the          as a cut-off value for determining insufficient
             studies in the Italian population, even if the modi-    intake [32]. This could be incorrect because the
             fied dietary history overestimated the intakes [36].    chronic disease widespread in geriatrics might
                                                                     interfere with the dietary intake for groups of eld-
             Food-Frequency Lists                                    erly subjects [40].
                                                                        The US RDA for the elderly are set for people
             As in the diet history, the food-frequency method       aged over 51 years (with a reference body weight
             uses an interview, but the questions refer only to      of 65 and 77 kg and a reference height of 160 and
             items previously listed and do not require active       173 cm for women and men, respectively) [39].
             recall. The food-frequency checklists are simple to     Other countries have established their RDA for
             administer; they identify usual food intake rather      subjects over 60 years of age: the French RDA are
             than food consumption for specific periods, elimi-      set for people aged over 65 years (with a reference
             nating the variance associated with an individual’s     body weight of 60 and 70 kg for women and men,
             day-to-day changes in eating [37]. Food-frequency       respectively) [39]. In Bulgaria, the RDA are set for
             lists indicate only food patterns and can distin-       subjects over 90 years of age [41].
             guish adequate from inadequate diets.                      In Italy, the recommended nutrient levels
                                                                     (LARN) [42] are valid for a population up to 60
             Mini Nutritional Assessment (MNA)                       years old,while all the elderly are placed in a unique
                                                                     ‘geriatric’ group of age over 60. In a recent study of
             The Mini Nutritional Assessment (MNA) is a rap-         the Italian population aged 70–75 years,the authors
             idly administered, simple tool for evaluating the       [35] showed that in both genders energy and
             nutritional status of older persons.It consists of 18   macro-nutrient mean values were similar to LARN