Tohoku J. Exp. Med., 2001, 193 (1)
Determination of Optimal Protein Contents for a Protein Restriction Diet in Type 2 Diabetic Patients with Microalbuminuria
TAKUMA NARITA, JUN KOSHIMURA, HIROYUKI MEGURO, HIROJI KITAZATO, HIROKI FUJITA and SEIKI ITO
Division of Geriatric Medicine, Akita University Hospital, Akita 010-8543
To establish the method by which the optimal dietary protein content for type 2 diabetic patients with nephropathy could be determined, dietary protein content was reduced in gradated steps and renal function was evaluated at the completion of each diet. Eight type 2 diabetic patients with microalbuminuria were examined in this study. Renal function, urinary albumin excretion rate (AER) and urinary excretion rates of prostaglandins were evaluated at the completion of each of three consecutive one-week dietary periods where the protein content was 1.2, 0.8 and 0.6 gkg Body Weight (BW)1day1 on the first, second and third week, respectively. Filtration fraction (FF), AER and urinary excretion rates of prostaglandin E2 and 6-keto-prostaglandin F1a significantly decreased in response to reduced dietary protein content from 1.2 to 0.8 gkg BW1day1. No additional decreases in FF, AER and urinary excretion rates of these two prostaglandins were obtained after the 0.6 gkg BW1day1 low protein diet period. The method evaluating renal hemodynamics at the completion of several consecutive one-week dietary periods was confirmed to be useful to determine the optimal protein contents in type 2 diabetic patients with nephropathy. The result showed that the optimal protein content in type 2 diabetic patients with microalbuminuria was 0.8 gkg BW1day1 and protein restriction of less than 0.8 gkg BW1day1 was not necessary for patients with this stage of diabetic nephropathy. A part of reasons in which FF decreased after reduced protein content in diet may be due to decreased prostaglandins production in the kidneys.
Keywords optimal dietary protein content; type 2 diabetes mellitus; microalbuminuria; diabetic nephropathy; prostaglandin
© 2001 Tohoku University Medical Press
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Tohoku J. Exp. Med., 2001, 193, 45-55
Address for reprints: Takuma Narita, Division of Geriatric Medicine, Bkita University Hospital, 111 Hondo, Bkita 010-8543, Japan.
e-mail: narita@med.akita-u.ac.jp