Associations among the plasma amino acid profile, obesity, and glucose metabolism in Japanese adults with normal glucose tolerance.

Chisa Takashina,Noriko Oyama-Manabe,Ichizo Tsujino,Taku Watanabe,Daisuke Ikeda,Takahiro Sato,Yoichi M Ito,Hiroshi Ohira,Masaharu Nishimura,Asuka Yamada,Shinji Sakaue,Yoshinori Otsuka

doi:10.1186/s12986-015-0059-5

Chisa Takashina, Noriko Oyama-Manabe + Show 10 more

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https://doi.org/10.1186/s12986-015-0059-5

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Abstract

BackgroundAmino acids (AAs) are emerging as a new class of effective molecules in the etiology of obesity and diabetes mellitus. However, most investigations have focused on subjects with obesity and/or impaired glucose regulation; the possible involvement of AAs in the initial phase of glucose dysregulation remains poorly understood. Furthermore, little attention has been given to possible associations between the pattern/degree of fat deposition and the plasma AA profile. Our objective was therefore to determine the relationships between plasma AA concentrations and the type/degree of obesity and glucose regulation in Japanese adults with normal glucose tolerance.MethodsEighty-three subjects with normal glucose tolerance were classified as obese or nonobese and as visceral obesity or nonvisceral obesity. Correlations between the plasma levels of 23 AAs and somatometric measurements, visceral fat area (VFA), subcutaneous fat area (SFA), and 75-g oral glucose tolerance test results were analyzed.ResultsObesity or visceral obesity was associated with higher levels of branched-chain AAs (isoleucine, leucine, and valine), lysine, tryptophan, cystine, and glutamate but lower levels of asparagine, citrulline, glutamine, glycine, and serine (p < 0.04). Age- and gender-adjusted analyses indicated that VFA was positively correlated with tryptophan and glutamate levels, whereas VFA and SFA were negatively correlated with citrulline, glutamine, and glycine levels (p < 0.05). The fasting and 2-h plasma glucose levels or the homeostasis model assessment of insulin resistance were positively correlated with valine, glutamate, and tyrosine levels but negatively correlated with citrulline, glutamine, and glycine levels. The homeostasis model assessment for the β-cell function index was positively correlated with leucine, tryptophan, valine, and glutamate levels but negatively correlated with citrulline, glutamine, glycine, and serine levels (p < 0.05).ConclusionsThe present study identified specific associations between 10 AAs and the type/degree of obesity, and indices of glucose/insulin regulation, in Japanese adults with preserved glucose metabolism. With the growing concern about the increasing prevalence of obesity and diabetes, the possible roles of these AAs as early markers and/or precursors warrant further investigation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-015-0059-5) contains supplementary material, which is available to authorized users.

Highlights

Amino acids (AAs) are emerging as a new class of effective molecules in the etiology of obesity and diabetes mellitus
Little attention has been given to possible associations between the pattern and degree of fat deposition and the plasma AA profile
Using a detailed analysis of the indices of insulin resistance, sensitivity, and secretion derived from the 75-g oral glucose tolerance test (75-g Oral glucose tolerance test (OGTT)), this study identified significant associations between AAs and the development of aberrant glucose regulation in nondiabetic Japanese adults

Summary

Introduction

Amino acids (AAs) are emerging as a new class of effective molecules in the etiology of obesity and diabetes mellitus. Most investigations have focused on subjects with obesity and/or impaired glucose regulation; the possible involvement of AAs in the initial phase of glucose dysregulation remains poorly understood. Little attention has been given to possible associations between the pattern and degree of fat deposition and the plasma AA profile This is of clinical interest because visceral adipose tissue demonstrates a stronger association with metabolic disturbances and cardiovascular risks than subcutaneous adipose tissue [9, 10]. A community-based observational study documented that Asians have a lower BMI but a higher percentage of body fat than Caucasians [14] Based on these and other publications from around the world [15, 16], a definition for obesity specific to the Japanese population was proposed as BMI ≥ 25 kg/m2 [17], which differed from that for Europeans (BMI ≥ 30 kg/m2)

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