Can dietary changes reduce blood pressure in the long term?

Recent dietary guidelines for the prevention and treatment of hypertension emphasized a healthy eating pattern called the Dietary Approaches to Stop Hypertension (DASH) diet, in addition to avoidance of obesity, high salt intake, and excessive alcohol intake. Our new challenge is to examine the long-term efficacy and effectiveness of dietary change, including the DASH diet, on blood pressure in the general population, or in a high-risk population. We reviewed recent short-term and long-term studies, both observational and interventional, which investigated whether dietary change can reduce blood pressure.

The efficacy of several nutrients has been investigated in short-term trials (e.g. polyunsaturated fatty acids, including omega-3 fatty acids, and trans fatty acids), but no substantial effect of these nutrients on blood pressure has been proved, except for dietary fiber. The PREMIER trial showed the effectiveness of implementing the DASH diet for 6 months in addition to the established recommendations on lifestyle modification, but other long-term trials of dietary modification did not show sufficient blood pressure reduction. However, long-term observational studies have shown that a higher intake of fruit and vegetables and a lower intake of red meat (except fish) can prevent higher blood pressure increase with age.

More effective programs of dietary modification are needed to achieve greater reduction of blood pressure. Long-term studies of population-wide dietary interventions to decrease the blood pressure level of a whole population are also needed.