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Isocaloric carbohydrate deprivation induces protein catabolism despite a low T3‐syndrome in healthy men
Author(s) -
Bisschop P. H.,
Sauerwein H. P.,
Endert E.,
Romijn J. A.
Publication year - 2001
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.2001.01158.x
Subject(s) - endocrinology , medicine , carbohydrate , catabolism , excretion , carbohydrate metabolism , protein catabolism , hormone , chemistry , biology , metabolism , biochemistry , amino acid
Dietary carbohydrate content is a major factor determining endocrine and metabolic regulation. The aim of this study was to evaluate the relation between thyroid hormone levels and metabolic parameters during eucaloric carbohydrate deprivation. We measured thyroid hormone levels, resting energy expenditure (by indirect calorimetry) and urinary nitrogen excretion in six healthy males after 11 days of three isocaloric diets containing 15% of energy equivalents as protein and 85%, 44% and 2% as carbohydrates. In contrast to the high and intermediate carbohydrate diets, carbohydrate deprivation decreased plasma T 3 values (1·78 ± 0·09 and 1·71 ± 0·07 vs. 1·33 ± 0·05 nmol/l, respectively, P < 0·01), whereas reverse T 3 , T 3 uptake and free T 4 levels increased simultaneously compared to the other two diets. TSH values were not different among the three diets. Although dietary carbohydrate content did not influence resting energy expenditure, carbohydrate deprivation increased urinary nitrogen excretion (10·91 ± 0·67 and 12·79 ± 1·14 vs. 15·89 ± 1·10 g/24 h, respectively, P = 0·03). Eucaloric carbohydrate deprivation increases protein catabolism despite decreased plasma T 3 levels. Because it has previously been shown that starvation decreases plasma T 3 levels, resting energy expenditure and nitrogen excretion, these discordant endocrine and metabolic changes following carbohydrate deprivation indicate that the effects of starvation on endocrine and metabolic regulation are not merely the result of carbohydrate deprivation.