Dr Rebecca Suckling, of St George's University of London, and colleagues looked at the effects of reductions in salt intake in patients with high normal BP.
They examined the impact of such an intervention on BP and urinary albumin excretion.
The study included 44 patients with type-2 diabetes or impaired glucose tolerance who were not on any medication for BP or diabetes.
In order to study the effect of salt reduction in a double-blind fashion, the researchers gave all the patients advice on how to reduce dietary salt intake to below 6g per day.
Patients then received either a placebo or salt-replacement tablets, which were designed to restore salt intake to pre-study levels.
After six weeks, patients switched treatments so that both groups received both interventions.
On average, patients achieved cuts in salt intake of 2.9g/day. This led to a drop in systolic BP of 4mmHg (from 135 mmHg) and in diastolic of 2mmHg (from 81mmHg) and an albumin-creatinine ratio reduction of 12 per cent.
Presenting the findings, Dr Suckling said: 'This suggests potential benefits of such a salt reduction for renal and cardiovascular disease, and certainly supports (the idea that) all diabetics should be on a reduced salt diet, to at least less than 6g, if not (lower).'