Sources of protein and polyunsaturated fatty acids of the diet and microalbuminuria in type 2 diabetes mellitus.

BACKGROUND: Albuminuria excretion rate above the reference range and below albustix positive proteinuria (20-199 microg/min) is known as microalbuminuria and has been associated with an increased risk of death and progression to renal failure. Besides hyperglicemia and high blood pressure levels, dietary factors can also influence albuminuria.

OBJECTIVE: To evaluate possible associations of dietary components (macronutrients and selected foods) with microalbuminuria in type 2 diabetic patients.

METHODS: In this cross-sectional study, 119 normoalbuminuric [NORMO; 24-h urinary albumin excretion (UAE) < 20 microg/min; immunoturbidimetry] and 62 microalbuminuric (MICRO; UAE 20-199 microg/min) type 2 diabetic patients, attending the Endocrine Division, Hospital de Clínicas de Porto Alegre (Brazil), without previous dietary counseling, underwent 3-day weighed-diet records, and clinical and laboratory evaluation.

RESULTS: MICRO patients consumed more protein (20.5 +/- 4.4 vs. 19.0 +/- 3.5% of total energy; p = 0.01) with a higher intake from animal sources (14.5 +/- 4.7 vs. 12.9 +/- 3.8% of total energy; p = 0.015) than NORMO patients. The intakes of PUFAs (8.6 +/- 2.9 vs. 9.7 +/- 3.3% of total energy; p < 0.03), PUFAs from vegetable sources (7.3 +/- 3.4 vs. 8.6 +/- 3.7% of total energy; p = 0.029), plant oils [0.2 (0.1-0.6) vs. 0.3 (0.1-0.9) mg/kg weight; p = 0.02] and margarines [3.3 (0-75.7) vs. 7.0 (0-51.7) g/day; p = 0.01] were lower in MICRO than in NORMO. In multivariate logistic regression models, adjusted for age, gender, presence of hypertension and fasting plasma glucose, intake of total protein (% of total energy; OR 1.104; 95% CI 1.008-1.208; p = 0.032) was positively associated with microalbuminuria. The intakes of total PUFAs (% of total energy; OR 0.855; 95%CI 0.762-0.961; p = 0.008), PUFAs from vegetable sources (% of total energy; OR 0.874; 95%CI 0.787-0.971; p = 0.012) and plant oils (mg/kg weight; OR 0.036; 95% CI 0.003-0.522; p = 0.015) were negatively associated with microalbuminuria.

CONCLUSIONS: In type 2 diabetic patients, the high intake of protein and the low intake of PUFAs, particularly from plant oils, were associated with the presence of microalbuminuria. Reducing protein intake from animal sources and increasing the intake of lipids from vegetable origin might-reduce the risk of microalbuminuria.