Lead investigator Dr. Pauline A. Swift from St. George's Hospital Medical Center, London stated that, "This study...contributes to the growing and compelling evidence that salt reduction reduces blood pressure and thus will reduce cardiovascular risk. "It also demonstrates for the first time that salt reduction reduces urine protein excretion, which in turn will reduce the risk of progressive renal disease and may also further reduce cardiovascular risk."

Dr. Swift and colleagues investigated the effects of reducing salt intake from about 10 grams per day to 5 grams per day in 40 nondiabetic black patients with hypertension. None of the subjects were receiving blood pressure lowering medications. With salt restriction, the mean blood pressure fell from 159/101 mm Hg to 151/98 mm Hg, the authors report. There were parallel falls in mean daytime and nighttime ambulatory blood pressures.

During the same interval, urine protein excretion declined by 18 mg per 24 hours and the mean urine protein to creatine ratio decreased from 6.6 mg/mmol to 5.7 mg/mmol, the results indicate.

Urine protein excretion did not correlate with blood pressure changes, the researchers note, but the change in urine sodium excretion correlated significantly with the change in urinary protein excretion.

Plasma renin activity increased from 0.1 ng/mL to 0.2 ng/mL with salt reduction, the investigators report.

"Groups with the highest cardiovascular and renal risk, such as diabetics or individuals with renal disease, might be expected to have the greatest personal benefits from salt reduction," Dr. Swift explained. "In terms of preventing cardiovascular deaths, however, all populations worldwide, should be encouraged to reduce salt intake, at least to the WHO recommended intake of 5 g/day."

Source: Diabetes In Control.com: Hypertension 2005;46:308-312.