The Nurses' Health Study followed 88,517 female nurses, whose ages ranged from 34 to 59 at the beginning of the study in 1980. None of them had diabetes or cardiovascular disease at the inception of the study. They reported their typical dietary fare seven times over the course of the 24-year study, with each report reflecting their dietary habits from each previous year.
Researchers then analyzed their diets and assigned them a DASH score according to their intake of eight food and nutritional factors. The higher the DASH score, the better the diet. A high score meant a diet that included plenty of fruits, vegetables, nuts, legumes, and whole grains and consumption of low-fat dairy products in quantities close to the recommended dietary guidelines. Consumption of processed and red meats, sodium, and sweetened beverages led to lower scores.
In previous studies high DASH scores have been proven to lower both systolic and diastolic (top and bottom numbers, respectively) blood pressure readings, even in patients with high blood pressure. The DASH diet is also linked to a reduction in low-density lipoproteins (the bad LDL) cholesterol. Both these factors lead to a reduced risk of stroke and heart disease
