Changes in renal function during weight loss induced by high vs low-protein low-fat diets in overweight subjects.
BACKGROUND
Due to the high satiating effect of protein, a high-protein diet may be desirable in the treatment of obesity. However the long-term effect of different levels of protein intake on renal function is unclear.


OBJECTIVE
To assess the renal effects of high vs low protein contents in fat-reduced diets.


METHODS
Randomized 6 months dietary intervention study comparing two controlled ad libitum diets with 30 energy (E%) fat content: high-protein (HP; 25 E%) or low-protein, (LP, 12 E% protein). All food was provided by self-selection in a shop at the department, and high compliance to the diet composition was confirmed by measurements of urinary nitrogen excretion.


METHODS
65 healthy, overweight and obese (25<body mass index (BMI)<34 kg/m2).


RESULTS
Dietary protein intake changed from 91.1 g/d to a 6 months intervention average of 70.4 g/d (P<0.05) in the LP group and from 91.4 g/d to 107.8 g/d (P<0.05) in the HP group, producing changes in glomerular filtration rate (GFR) of -7.1 ml/min in the LP group and +5. 2 ml/min in the HP group (group effect: P<0.05). Kidney volume decreased by -6.2 cm3 in the LP group and increased by +9.1 cm3 in the HP group (P<0.05), whereas albuminuria remained unchanged in all groups.


CONCLUSIONS
Moderate changes in dietary protein intake cause adaptive alterations in renal size and function without indications of adverse effects.
Skov
A R
AR
Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Copenhagen, Denmark.
Toubro
S
S
Bülow
J
J
Krabbe
K
K
Parving
H H
HH
Astrup
A
A
D000293:Adolescent; D000328:Adult; D000419:Albuminuria; D015992:Body Mass Index; D018752:Diet, Fat-Restricted; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000652:urine; D009765:Obesity / Q000178:diet therapy*; D015431:Weight Loss
D004044:Dietary Proteins; D009584:Nitrogen