NUTRITIONAL EFFECTS OF DIETARY-PROTEIN RESTRICTION IN INSULIN-DEPENDENT DIABETES-MELLITUS

The effects of dietary protein deprivation in insulin-dependent diabet es mellitus (IDDM) have been investigated in a merely rudimentary fash ion in human subjects, Moderate dietary protein restriction of 0.6 g/( kg ideal body weight.d) over 3 mo in free-living IDDM patients produce s increased adiposity during weight maintenance and decreased muscle s trength. These effects might have been predicted from studies of prote in deprivation in diabetic subjects, indicating impairment of nitrogen retention, The clinical consequences of dietary protein restriction i n IDDM may be more complex than described to date, This is suggested b y the overriding paradox that the actions of insulin on protein synthe sis are inconsistent: among in vitro, animal and human in vivo models. The inconsistency and the observation that insulin deficiency in huma ns accelerates both proteolysis and protein synthesis imply that knowl edge about insulin, diabetes and protein metabolism in humans is inade quate and should be studied in increasing detail. Better understanding of the clinical consequences of dietary protein restriction in diabet es, both beneficial and adverse, is likely to come from future studies incorporating clinically relevant levels of insulin deficiency and pr otein deprivation into studies of bodily function, clinical outcomes a nd specific examination of the metabolism of individual proteins.