The DASH diet is designed to prevent the development of hypertension (high blood pressure) by modifying dietary patterns for life. It is meant to help shift one’s eating habits towards consuming delicious but healthy foods, and thus keep high blood pressure from developing.
This is primarily through reducing sodium intake by choosing the right foods and eating a range of foods that offer plenty of nutritional value and are rich in potassium, calcium and magnesium.
Several trials have been carried out to help identify and quantify the benefits of the DASH diet. These include:
Thus the DASH diet is not a crash or deprivation diet but one which allows for complete nutrition and long-term establishment of healthy eating. To reduce sodium consumption still further, a low sodium version of the DASH diet is also available. This reduces sodium to 1500 mg a day from the standard 2300 mg/day, which itself is a considerable improvement on the average American diet.
The DASH trial found that this diet brought about lower blood pressure and LDL cholesterol compared with the average American diet, either as such or with added fruits and vegetables. This trial included 459 adults and the DASH diet was compared with two others that had a daily sodium intake of 3000 mg.
The other diets represented the average American diet without and with added fruits and vegetables. However, none of the dieters followed a vegetarian plan or one which included foods that would not be eaten at some point by average Americans. The DASH diet had the most effect on reducing blood pressure, while the diet with added fruit and vegetables showed intermediate results. This was seen in individuals who had normal or elevated blood pressures.
The DASH-Sodium trial on the other hand had 412 subjects who followed either the DASH or a typical American diet. Daily sodium levels were set at high (3,300 mg), low-moderate (2,300 mg) and low (1,500 mg) respectively, in each of these diets. Sodium restriction was invariably found to reduce the blood pressure, but the effect was greater with the DASH diet. It could also be said that the DASH diet was even more effective with sodium restriction.
The PREMIER trial had 810 participants in three groups, the first whom received only advice but no counseling for behavior changes; the second were on an established treatment plan with counseling for six months; and the third with a plan, counseling and the DASH diet.
While the blood pressure was reduced in all three groups, the advice-only group had the least weight loss while the third group showed the most reduction in blood pressure and weight.