The Effects of Dietary Patterns on Urinary Albumin Excretion: Results of the Dietary Approaches to Stop Hypertension (DASH) Trial

Abstract

Dietary studies designed to decrease the urinary albumin excretion rate (AER) typically reduce protein by increasing lower protein plant foods and decreasing higher protein animal products. STUDY DESIGN: We evaluated AER while increasing protein intake in the Dietary Approaches to Stop Hypertension (DASH) Trial (randomized, parallel group, 8 week controlled feeding). SETTING & PARTICIPANTS: 378 individuals without diabetes with prehypertension or stage I hypertension. INTERVENTION: The DASH diet, 18% energy from protein, emphasizes, among other features, low-fat dairy products; and the fruit/vegetable (FV) and control diets, each with 15% energy from protein. OUTCOME: AER. MEASUREMENTS: We measured AER by using immunoassay and covariates at baseline and after 8 weeks. RESULTS: Baseline AER had a geometric mean value of 4.0 +/- 0.2 (SE) mg/24 h. In 285 participants with baseline AER less than 7 mg/24 h, AER was unchanged by diet treatment (geometric mean, 2.5 +/- 0.2 mg/24 h in the control diet, 3.0 +/- 0.2 mg/24 h in the FV diet, and 2.8 +/- 0.2 mg/24 h in the DASH diet). Conversely, in 93 participants with baseline AER of 7 mg/24 h or greater, end-of-feeding AER was lower in the FV diet (6.6 +/- 1.0 mg/24 h) than in the control (11.4 +/- 1.8 mg/24 h; P = 0.01) or DASH diets (11.7 +/- 1.6 mg/24 h; P = 0.005). The DASH and control diets were not different (P = 0.9). LIMITATIONS: Long-term AER change not studied. CONCLUSIONS: The decrease in AER after 8 weeks occurred in only those with high-normal baseline AER in the FV diet, in a pattern distinct from the blood pressure decrease. The DASH diet did not increase AER despite a 3% increase in energy from protein.