The first clinical study was called "DASH," and it tested nutrients as they occur together in food. Its findings showed that blood pressures were reduced with an eating plan that is low in saturated fat, cholesterol, and total fat, and that emphasizes fruits, vegetables, and low-fat dairy foods. This eating plan -- known as the DASH eating plan or DASH diet -- also includes:
- Whole-grain products
The DASH diet is reduced in red meat, sweets, and sugar-containing beverages. It is rich in magnesium, potassium, and calcium, as well as protein and fiber.
DASH compared three eating plans:
- A plan similar in nutrients to what many Americans consume
- A plan similar to what Americans consume but higher in fruits and vegetables
- The DASH diet.
All three plans included about 3,000 milligrams of sodium daily. None of the plans were vegetarian or used specialty foods.
Results were dramatic: Both the fruits and vegetables plan and the DASH diet reduced blood pressure. But the DASH diet had the greatest effect, especially for those with high blood pressure. Furthermore, the blood pressure reductions came fast -- within 2 weeks of starting the DASH diet.
The second study was called "DASH-Sodium," and it looked at the effect on blood pressure of a reduced dietary sodium intake as participants followed either the DASH diet or an eating plan typical of what many Americans consume.
Participants were randomly assigned to one of the two eating plans and then followed for a month at each of three sodium levels. The three sodium levels were:
- A higher intake of about 3,300 milligrams per day (the level consumed by many Americans)
- An intermediate intake of about 2,400 milligrams per day
- A lower intake of about 1,500 milligrams per day.
Results showed that reducing dietary sodium lowered blood pressure for both eating plans. At each sodium level, blood pressure was lower on the DASH diet than on the other eating plan. The biggest blood pressure reductions were for the DASH diet at the sodium intake of 1,500 milligrams per day. Those with hypertension saw the biggest reductions, but those without it also had large decreases.
Those on the 1,500-milligram sodium intake eating plan, as well as those on the DASH diet, had fewer headaches. Other than that and blood pressure levels, there were no significant effects caused by the two eating plans or different sodium levels.
DASH-Sodium shows the importance of lowering sodium intake, regardless of your eating plan. But for a true winning combination, follow the DASH diet and lower your intake of salt and sodium.