Eating a diet rich in fruits and vegetables and low in saturated fats can significantly lower the risk of heart attack for people with mildly elevated blood pressure, Johns Hopkins University researchers say.
The diet they examined, called the Dash diet (Dietary Approaches to Stop Hypertension),, was designed to lower blood pressure and cholesterol. In this new study, it reduced the risk of heart attack by almost 20 %, the researchers said.
Reduce fats, red meats and sugars
"Heart disease is an important cause of mortality and morbidity," said lead researcher Dr Nisa M. Maruthur, an assistant professor of medicine at Hopkins' School of Medicine. "Thus, adoption of the Dash diet should have important benefits on a public health scale."
The diet also calls for reducing fats, red meat, sweets and sugary beverages, and replacing them with whole grains, poultry, low-fat dairy products, fish and nuts. The eating plan is recommended by the US Dietary Guidelines for Americans and the American Heart Association.
For the study, published online in Circulation: Cardiovascular Quality and Outcomes, Maruthur's team studied 436 people with high blood pressure or borderline hypertension who were not taking blood pressure medication.
The participants were assigned to either the Dash diet; a 'typical' diet, which is low in important minerals and high in saturated fat, total fat and cholesterol; or a 'typical' diet plus more fruits and vegetables.
High blood pressure, or hypertension, is a major risk factor for heart disease, stroke, heart failure and kidney disease.
To determine their risk of having a heart attack over 10 years, the researchers used the Framingham Heart Study risk equation.
After eight weeks, the Dash dieters, who were eating nine to 11 servings of fruits and vegetables a day, had reduced their risk of heart attack 18% compared with those eating the 'typical' diet. They also saw their low-density lipoprotein ("bad") cholesterol levels reduced by about 7% and their systolic blood pressure lowered by 7 mm Hg.
While both whites and blacks benefited from the Dash diet, black participants had the greatest benefit, the researchers noted. Blacks on the Dash diet saw their heart risk decline by 22% over those on a typical diet, versus 8% for whites.
Those who ate the 'typical' diet plus fruits and vegetables reduced their risk of heart attack by 11% compared with those eating the usual fare.
"The problem with hypertension is that it really is a silent killer because you do not feel it," said Samantha Heller, clinical nutrition coordinator at the Centre for Cancer Care at Griffin Hospital in Derby, Conn. Millions of people have no idea their blood pressure is high and are walking around like "ticking time bombs," she said.
Those who know they are hypertensive do not always know what to do about it aside from taking medication, Heller added.
Diet tweaks can make the difference
"The good news is that with a few dietary tweaks, the risk of these diseases and their co-morbidities can drop considerably. For example, add a salad or side of vegetables with lunch. Have fruit for dessert. Make your mashed potatoes with olive oil and low-fat milk. Top your pizza with part-skim mozzarella, broccoli, spinach and mushrooms," she said.
"The Dash eating plan is a good way to go for people looking to lower their blood pressure and improve heart health," she said.
Another expert, Dr Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, said although the Dash diet has been shown to lower systolic blood pressure and total cholesterol levels, changing risk factors does not always translate to a reduction in actual heart disease.
"It is therefore essential to hold dietary modification and other forms of lifestyle modification to the same gold standard that statins and antihypertensive medical therapies have been held to," he said. What's needed are prospective randomised trials that demonstrate actual reduction in coronary heart disease events, Fonarow said.