Plasma and Erythrocyte Amino Acid Concentrations in Anorexia Nervosa

Abstract

Plasma and erythrocyte amino acid concentrations in seven female patients in the acute stage of anorexia nervosa were compared with values in the same subjects after refeeding, and with normal controls. We also compared these values with literature values from patients with protein-calorie malnutrition and prolonged starvation in an attempt to identify a biological indicator of severity and prognosis. Our data indicate: (1) Routine laboratory analyses that reflect protein status do not differentiate normal subjects from patients with anorexia nervosa. (2) The plasma aminogram in the acute stage of anorexia nervosa differs from normal, and differs from values reported for both protein malnutrition and prolonged starvation. (3) The Whitehead ratio clearly separates the acutely ill anorectic state from the treated state and from normal controls. (4) Both erythrocyte and plasma amino acid concentrations differ from normal in anorexia nervosa, but changes in erythrocyte concentrations are more obvious. (5) Erythrocyte glycine concentrations are unique, in that values were persistently elevated at all stages of illness in anorexia nervosa. (6) Erythrocyte-to-plasma amino acid ratios do not provide a biological index of severity and prognosis for patients with anorexia nervosa, in contrast to data reported for individuals with protein malnutrition.

Plasma amino acids in anorexia nervosa

“…This Plasma amino acids in anorexia nervosa D Moyano et al suggests an increased free radical generation and a probable adaptive scavenging effort of the antioxidant system to cope with it. The different results observed in cystine concentration and Met/Cys ratio in anorexic adults (Halmi et al, 1987) might be explained by different requirements for sulfur amino acids in adolescence, different habits and diets in diverse geographical areas, and also by the reduced number of anorexic adult females included in the study (Halmi et al, 1987).…”

“…This may occur due to an impaired activation of N-acetylglutamate synthetase which requires arginine, and in part to the insuf®cient synthesis of enzymatic proteins of the urea cycle owing to a reduced protein intake (Brusilow & Horwich, 1995). This observation, together with the signi®cant increase in absolute glycine values (Halmi et al, 1987), as well as in the Gly/Val ratio suggest that these patients restrict not only energy, as is commonly thought, but also proteins in their strictly selfcontrolled diets, resulting in an undernutrition similar to marasmus (Madruga et al, 1993). The low arginine concentration might also have other consequences, because this amino acid is a precursor for the synthesis of creatine and nitric oxide.…”

“…In our study and as stated also by other authors (Felig et al, 1969), lumping amino acids into essential and non-essential groups and calculating the ratio between these groups during starvation would fail to consider the divergent response of some amino acids. Therefore, the Whitehead ratio of non-essential/essential amino acids did not enhance interpretation as applied to our anorexic adolescents (Whitehead & Dean, 1964), although it did in another one dealing with adult anorexic patients (Halmi et al, 1987). The interpretation of the pattern of adaptive response of plasma amino acids to anorexia is dif®cult because it is the result of intermediary metabolism in visceral and peripheral tissues under the in¯uence of a range of hormones (Jackson & Grimble, 1990;Soliman et al, 1992).…”

“…Branched-chain amino acids are usually low in most malnourished states except for starvation and marasmus (Jackson & Grimble, 1990;Soliman et al, 1992). Alanine and glutamine are usually low in malnourished individuals (Hortin et al, 1994;Chin et al, 1992), but high-normal in anorexia and marasmus (Halmi et al, 1987;Soliman, 1992). Sulphur amino acids are generally low in malnourished individuals, but only cystine seems to decrease in anorexia, so the Met/Cys ratio is different to that in other malnutrition states (Roediger, 1995;Ghisol® et al, 1978).…”

“…The biochemical evaluation of the nutritional status is very useful at diagnosis and for the follow-up, allowing for a more speci®c identi®cation and treatment of de®cient factors which results in a shorter and more ef®cient recovery (Nussbaum, 1992;Madruga, 1993). However, in spite of being a severe nutritional disorder, it is associated with rather mild abnormalities of the classical parameters of malnutrition (Schebendach & Nussbaum, 1992;Halmi et al, 1987). Although amino acid and protein metabolism have commonly been considered to lie at the center of the metabolic complexities of severe undernutrition (Jackson & Grimble, 1990), few reports of amino acid patterns in anorexia nervosa have been published (Halmi et al, 1987;Schweiger et al, 1986;Schreiber et al, 1991).…”