Persistencia de déficits nutricionales tras la recuperación de peso a corto plazo
en adolescentes con anorexia nerviosa.
(Persistence of nutritional deficiencies after short-term weight recovery in adolescents with anorexia nervosa.)
FUENTE: PSIQUIATRIA.COM. 2003; 7(5)
J.Castro*; R.Deulofeu**; A.Gila*; J.Puig*; J.Toro*.
*Servicio de Psiquiatría y Psicología Infantil y Juvenil.
**Servicio de Bioquímica Clínica. Hospital Clínico Universitario de Barcelona.
E-mail: 16812jcf@comb.es
PALABRAS CLAVE: Déficits nutricionales, Anorexia nerviosa, Adolescentes.
KEYWORDS: Nutritional deficiencies, Anorexia nervosa, Adolescents.)
[otros artículos] [4/2/2003]
Resumen
Objetivos: Estudiar las alteraciones nutricionales en adolescentes con anorexia nerviosa y establecer si ciertas
deficiencias persisten tras la recuperación de peso a corto plazo.
Método: Sesenta y una paciente de entre 10 y 19 años ingresadas en una Unidad de Referencia para Trastornos
de la Conducta Alimentaria, que cumplían criterios diagnósticos DSM-IV para anorexia nerviosa fueron evaluadas
en el momento del ingreso y al alta hospitalaria tras la recuperación de peso. Se determinaron una amplia serie
de parámetros bioquímicos, nutricionales y hormonales.
Resultados: En el momento del ingreso no se encontraron deficiencias en las proteínas o lípidos, pero un número
elevado de pacientes presentaron alteraciones hormonales y déficit de ácido fólico eritrocitario y zinc. Tras la
realimentación, en el momento del alta, las alteraciones hormonales mejoraron de forma significativa (p<0,001).
Sin embargo, disminuyeron los hematíes y la hemoglobina (p<0,001) y el ácido fólico (p<0,05). El ácido fólico
eritrocitario y el zinc aumentaron pero no alcanzaron niveles normales.
Conclusiones: En una amplia proporción de adolescentes con anorexia nerviosa estaría recomendada la
administración de suplementos de ácido fólico y zinc durante la recuperación nutricional.La administración de
suplementos proteínicos y hormonales no parecen ser necesarios si se logra la recuperación de peso.
Abstract
Objectives: To study nutritional abnormalities in adolescent anorexia nervosa and to establish whether certain
abnormalities persist after short-term refeeding.
Method: Sixty-one patients aged 10 to 19 admitted to a Reference Unit for Eating Disorders between 1999 and
2000, with DSM-IV diagnosis of anorexia nervosa were evaluated at admission and at discharge. A range of
biochemical, nutritional and hormonal parameters were determined.
Results: At admission no protein or lipid deficiencies were found, although many patients presented hormonal
abnormalities, and red blood cell folate and zinc deficiencies.. Hormonal abnormalities reverted significantly
(p< .000) after renutrition. There were decreases in erythrocytes and hemoglobin (p< .000) and folic acid
(p< .05). Red blood cell folate and zinc increased but did not reach normal levels.
Conclusions: In a large proportion of adolescent anorexic patients supplementation of folic acid and zinc is
recommended although protein or hormonal replacement does not seem to be necessary.
Malnutrition in anorexia nervosa can be severe but assessment of nutritional status yielded inconsistent and
sometimes contradictory results. This may be due to heterogeneity in age and duration of disorder, or to small
sample size in some studies (1-4). Among the features most commonly described are anemia and leucopenia (5,
6) which appear to be related to bone marrow changes, though the mechanisms involved are not well known at
present (7).
However, these hematological abnormalities are not seen in all studies (8). Protein levels are also normal in many
cases (9), albeit in the low-normal range.
Impairment of micronutrient status, especially iron and zinc, is also frequent (10-13) but reports of highly
abnormal levels of vitamins (except for folic acid) are surprisingly rare (8, 9, 14). A thiamin deficit was found in
19% of a sample of adult anorexics (15), and it is common to find higher carotene concentrations (16, 17).
Nevertheless, many of these studies were carried out with adult anorexics of long duration and it is not clear
whether young adolescents, in whom the evolution time of the disorder is shorter, present marked biochemical
and nutritional deficiencies.
Endocrine abnormalities are also common in malnourished anorexia nervosa patients, especially low levels of
thyroid hormones (16, 18) and insulin-like growth factor-I (IGF-I) and its binding protein 3 (IGBP-3) (19-23).
Among the most frequent alterations in anorexia nervosa are abnormalities of the hypothalamic-pituitary-gonadal
axis, and impairment of gonadotropin secretion pattern, which is similar to that of the prepubertal stage (4).
The great majority of studies are cross-sectional, making it impossible to establish whether vitamins or other
micronutrients normalize after weight recovery or whether special nutritional supplements may be necessary (24).
In this respect, Rock and Vasantharajan (3) found a normalization of vitamin abnormalities in 13 patients with
renutrition in about 2-6 weeks. Caregaro et al. (22) found a prompt recovery of IGF-I in 20 adult anorexic
patients after short term weight increase. In a study of 33 eating disordered patients, McClain et al. (13) found
that zinc supplementation during hospitalization increased their plasma zinc level significantly in comparison with
patients without supplement. Nevertheless, no clear guidelines have yet been published for vitamins or trace
metals or other micronutrient supplementation in young patients with anorexia nervosa (25, 26).
The objective of the present study was to determine whether adolescent patients with short duration anorexia
nervosa have abnormal biochemical, nutritional and hormonal parameters and whether these alterations may be
reversed after short term weight recovery. The results of the present study will allow us to establish the rationale
for using vitamin or other micronutrient supplementation along with normal refeeding during hospitalization.
Method
Subjects and procedures
The group of patients comprised 61 children and adolescents aged 10 to 19 years who fulfilled the DSM-IV
diagnostic criteria (27) for anorexia nervosa. All patients were consecutively admitted to the Reference Unit for
Eating Disorders of the Child and Adolescent Psychiatry and Psychology Department of the Hospital Clínic
Universitari of Barcelona as inpatients between March 1999 and June 2000. Clinical characteristics were recorded.
Laboratory data were collected at admission and at discharge as part of the normal follow-up of anorexia nervosa
in our unit. Parents and patients were told why biochemical and hormonal parameters were being measured.
Study procedures were approved by the Ethics Committee of the Institution. Patients with concomitant disease
besides anorexia nervosa or those receiving hormonal therapy or any vitamin complex at admission were
excluded from the analysis.
During hospitalization all patients received a complete diet of about 1250 calories per day during the first days
which increased progressively to 2500 calories per day, but they did not receive vitamin or mineral supplements
or any hormonal replacement therapy. Treatment during admission is based on a multidisciplinary approach
combining biological management, nutritional rehabilitation, a behavioral program aimed to improve eating
patterns and weight, individual and group cognitive treatment, and individual and group parent counseling.
Laboratory test
The biochemical and hematological tests carried out at admission and at discharge included all standard
biochemical data, nutritional parameters, total proteins, prealbumin, ions (potassium, sodium, magnesium,
phosphorus, calcium, iron and zinc), vitamins (Vitamins B1, B6, B12, C, E, alfa and beta carotenes), folic acid,
and red blood cell folate, a complete hemogram including red blood cell count, hemoglobin, leucocytes and
platelet counts and endocrine parameters such as cortisol, triiodothyronine (T3), thyroxin (T4), thyrotropin (TSH),
IGF-I, IGFBP-3 and growth hormone (GH). All samples were taken in the morning. Gonadotropin levels were not
considered for the present study since they have been extensively studied elsewhere, and because 14 (24.1%) of
the female patients were still prepubertal.
Standard biochemical and hematological parameters were measured in an Olympus AU450 analyzer, (Cormedica,
Barcelona, Spain) using Olympus own reagents. Vitamin B12, and folic acid was measured by immunoassay using
an automated Immuno 1 system from Bayer (Quimica Farmaceutica Bayer, Barcelona, Spain). Vitamins B1 and
B6 were measured by HPLC using Chromsystems reagents (Chromsystems, Munich, Germany). Vitamin C, was
measured by HPLC by fluorimetric detection. Vitamin E and carotenes were also measured by HPLC using UV or
visible detection respectively. Hematological parameters were measured in an Advia hematology analyzer (Bayer,
Quimica Farmaceutica Bayer, Barcelona, Spain). Cortisol, HGH, IGF and IGFBP3 were measured by commercially
available radioimmunoassay as routinely measured at our institution.
Statistical analysis
Differences between mean initial values and follow-up measurements were analyzed using the Student's t test for
paired samples. The McNemar test was used to compare the incidence of abnormal parameters in the first and
second determinations. The level of statistical significance was p< .05. Statistical analysis was performed using
the SPSS package (28).
Results
General Characteristics
Mean age of patients was 14.9 years (SD=2.1), 58 (95.1%) patients were females and 3 (4.9%) were males.
Mean body mass index at admission was 15.3 (SD=1.3), and the mean percentage of weight loss was 23.1%
(SD=7.6). Mean period between the onset of the disorder (i.e., since the first weight loss) and admission was
15.3 months (SD=10.3). Fourteen (24.1%) female patients were prepubertal. The mean period of amenorrhea in
patients with secondary amenorrhea was 9.1 months (SD=7.7). Fifty-two (85.2%) were restrictive type and 9
(14.8%) were purgative. Table 1 shows patients data for anthropometric and demographic characteristics, ,
including weight gain and stay time. Treatment efficiency was shown by a signifcant increase in BMI after stay.
Tabla 1
Laboratory findings
Results for the biochemical, nutritional and hormonal parameters are shown in tables 2 and 3 as means ±SD. The
tables also present differences between admission and discharge
Tabla 2
Tabla 3
In general, hematological and basic biochemical parameters fell within normal ranges although many of them
were low to normal. At entry the only nutritional parameters with a mean level below reference values were red
blood cell folate and zinc. Of the hormonal parameters, IGF-1 and T3 also had mean scores below reference
values. Parameters in the low-normal range were total red blood cells, hemoglobin, iron, serum folic acid and
prealbumin. All other micronutrients were within normal ranges apart from folic acid and zinc, as mentioned
above.
Surprisingly, after short-term weight recovery, mean values of erythrocyte count, hemoglobin and folic acid
decreased significantly. In contrast, the concentrations of prealbumin increased and normalized; red blood cell
folate, and zinc also increased, but they did not reach normal values and the differences pre- and post- weight
recovery were not statistically significant. Among hormonal determinations, IGF-I, IGFBP-3 and T3 normalized
after weight recovery.
Prevalence of abnormal values
Although the majority of mean values were normal in this group of patients, some presented abnormal nutritional
and hormonal parameters (tables 4 and 5). For this analysis we only considered laboratory parameters for which
more than 2% of subjects presented abnormal levels at admission. The rest of the parameters listed in tables 2
and 3 were normal in more than 98% of subjects at both time points. Table 4 shows the percentages of subjects
with low nutritional and hormonal determinations at admission and at discharge. More than 80% of subjects had
low levels of T3, IGF-I and zinc at admission. More than 50% had low levels of red blood cell folate and more than
20% low levels of erythrocytes and plasma folic acid. The effect of refeeding was especially clear on T3 and IGF-1
and the percentages of patients with normal values for these parameters increased significantly. At discharge
abnormal levels of zinc and red blood cell folate remained in a substantial proportion of subjects and, surprisingly,
the percentage of patients with suboptimal levels of erythrocytes, hemoglobin and plasma folic acid increased.
Tabla 4
Table 5 shows the percentages of subjects with high levels of certain parameters at admission and at discharge.
In this case high levels of cortisol were found in 19% of subjects and high levels of alpha-carotenes in 20% but at
discharge the number of patients with these levels had decreased.
Tabla 5
Discussion
An increased prevalence of nutritional deficiencies can be considered the main issue of this study although no
basic biochemical abnormalities could be observed. Probably these findings are due to the fact that many
parameters are under strict homeostatic control and are unlikely to be altered without longer-term deficiencies or
till organ damage exist. In our study patients were very young and the duration of starvation or nutritional
restrictions were relatively short. Low levels of red blood cell counts, leucocytes and platelets have often been
reported in studies of anorexia nervosa patients (6) though not in all (8). In our sample, at admission there were
more patients with low levels of erythrocytes and hemoglobin than with low levels of leucocytes and platelets.
Furthermore, after short-term weight recovery, the percentage of patients with low leucocytes and platelets fell,
while the percentage of patients with low erythrocytes and hemoglobin rose. The plasma level of folic acid was in
the low-normal range and red blood cell folate was clearly below normal; these are factors that may have an
important role in the development of anemia. After refeeding, the percentage of patients with low red blood cell
folate was still very high and the percentage of patients with abnormal plasma folic acid increased, suggesting the
need for extra folic acid supplementation during renutrition. Other authors have pointed out the possibility of a
folate deficiency in adolescents with anorexia nervosa (29) and folate deficiency has also been related to
depressive symptoms in several psychiatric disorders, including anorexia nervosa (30). It seems that a
supplementation of folic acid may be appropriate for management of this group of patients. Although few subjects
had low serum levels of iron (11%), and the mean level was normal, though in the low range , iron
supplementation may be indicated in these patients to avoid deficit appearance during folic acid supplementation.
With the exception of folic acid, no absolute vitamin deficiency was seen in this study, again probably due to the
fact that the subjects were adolescents with short duration of the disorder. Other authors have not found vitamin
abnormalities in anorexia nervosa patients (8), and Rock and Vasantharajan (3) found suboptimal vitamin status
in 4 out of 13 patients, which normalized after short-term refeeding. Winston et al. (15) found a thiamin
deficiency in about 19% of 37 adult anorexic patients, but this was not the case in the present study. Serum
concentrations of alpha-carotene were high in 20% of subjects at admission. Other studies have found that alphacarotene levels were significantly higher in patients with a greater degree of eating pathology (31). The
percentage of subjects with high beta-carotene was lower than in other studies (17) although in our country mean
serum values of carotenes are lower than in other Caucasian populations (32).
Total protein levels were normal in all patients at admission and at discharge but prealbumin, the most sensitive
marker of protein depletion, was low in 16% of patients at admission a fact which is never found in healthy
adolescents . Only 3% of patients had abnormal prealbumin at discharge, demonstrating the efficacy of the
refeeding strategy for protein status . Rigaud et al. (9) concluded that protein markers are not sensitive to
malnutrition in anorexia nervosa, but this may have been because they considered only total proteins, and
albumin does not react so fast in this situation, due to the fact that prealbumin has a half life of 48 hours and
albumin of 19 days (33).
Zinc is a very important ion in many cell processes and also in brain homeostasis (34). The finding of such low
levels and the lack of recovery after the refeeding period suggests the need to accelerate zinc recovery with
supplementation. Other studies have found low levels of zinc in anorexic patients, which did not increase with
short-term renutrition if supplementation was not given (13) and it has been suggested that zinc deficiency may
be one of the factors that caused altered eating behavior, anxiety and depressive symptoms to persist (11, 12).
In other populations such as elite athletes, unusual nutritional habits may also lead to suboptimal zinc intake and
mild zinc deficiency (35). It is well known that zinc deficiency may induce anorexia, loss of weight, ageusia, hair
loss and mood changes.
The hormones most likely to present abnormalities seem to be T3 and IGF-I, as other studies have pointed out
(19,20,22,23)). With malnutrition they are low in the great majority of cases, but with weight recovery levels of
T3 and IGF-I reach normal values in the short term. Recovery of IGF-I may be related to bone formation and to
the improvement in bone mass (23, 36).
In summary, a great percentage of adolescent patients presented nutritional and hormonal abnormalities,
although none had severe vitamin deficiencies. It seems that the most persistent abnormalities after short-term
weight recovery in adolescents with anorexia nervosa are low levels of erythrocytes, hemoglobin, folic acid and
zinc.
Furthermore folic acid deficit may account for the persistence of anemia. Other abnormalities tend to normalize
fast after short-term refeeding, and therefore it does not seem advisable to add protein or vitamin
supplementations to the normal diet. The main conclusion is that extra supplements of folic acid, iron and zinc
could be beneficial to rapidly compensate deficits that cannot be recovered only with short standard nutrition
programs. These supplements may contribute to ameliorating anemia and folate and zinc deficiencies, and to
improve certain psychological abnormalities . Further controlled studies of the effects of these supplements on
both physical and psychological symptomatology would be of great interest.
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