BALTIMORE, MD - A new study suggests yet another reason for Americans to abandon
their current fatty diets in favor of one rich in fruits and
vegetables and low in saturated fat. Choosing these healthier options
appears to significantly reduce the long-term risk of heart disease
in patients with mildly elevated blood pressure, particularly African
Long known to reduce blood pressure and now recommended in national
guidelines, this healthier diet -- known as the DASH diet -- also
reduces heart disease risk, even in people who do not lose weight,
according to a Johns Hopkins study being published in the journal
Circulation: Cardiovascular Quality and Outcomes.
"One of the most noteworthy findings is the remarkable reduction in
heart disease risk among African Americans," says Nisa M. Maruthur,
M.D., M.H.S., an assistant professor of medicine in the Division of
General Internal Medicine at the Johns Hopkins University School of
Medicine and one of the study's authors. "African Americans in the
United States tend to have worse outcomes than whites from
cardiovascular disease, and here is one way they may be able to help
The DASH (Dietary Approaches to Stop Hypertension) eating plan
emphasizes fruits, vegetables and low-fat dairy products; includes
whole grains, poultry, fish and nuts; and is reduced in fats, red
meat, sweets and sugar-containing beverages.
Maruthur's research shows that subjects who ate the DASH diet likely
decreased their 10-year risk of coronary heart disease by 18 percent
over those who ate a more typical American diet; and by 11 percent
over those who ate a diet rich in fruits and vegetables but otherwise
similar to a typical American diet.
In African-American subjects, the decrease in 10-year risk of
coronary heart disease was even more pronounced: Those on the DASH
diet saw their risk decline by 22 percent over those on a typical
diet, compared to 8 percent for white subjects.
Compared to the study's control group, the DASH diet (with its nine
to 11 servings of fruits and vegetables a day) lowered blood
pressure, total cholesterol and LDL cholesterol as well as HDL
cholesterol. It had no effect on levels of triglycerides, fatty acids
also linked to heart disease.
The research was done using data from the DASH trial of the 1990s, in
which 459 people with elevated blood pressure not high enough to
require medication were sorted into three groups. Each group ate one
of three diets for eight weeks, the DASH diet, a diet rich in fruits
and vegetables but otherwise comparable to a typical diet, or a more
typical fatty American diet. All of the food was provided by
researchers, who carefully measured out portions and determined the
nutrient content of the meals being served. Using a risk assessment
calculator devised by the Framingham Heart Study, Maruthur's team was
able to estimate heart disease risk.
Maruthur says the reason that the diet likely reduces coronary heart
disease risk is that it reduces both blood pressure and blood
cholesterol levels, two independent risk factors for coronary disease.
One drawback of the study -- and most any study of lifestyle
interventions -- is that it relies on estimates for determining heart
disease risks in the long term. Researchers point out that it would
take too much time and money to follow people for the decades
required to see if the prescribed diet helps reduce actual heart
attacks and heart disease deaths.
For years, doctors and policy makers have talked about the
detrimental effects of the typical American diet on the nation's
health. Physician, advocacy and government groups have advocated for
widespread adoption of a diet similar to the DASH diet. But the
message, says Maruthur, still hasn't gotten through.
"It's no secret that we should be eating less saturated fat and more
fruits and vegetables," she says. "But how do we get the general
population to adopt the DASH diet? The public health benefits could
Lawrence J. Appel, M.D., M.P.H., and Steven T. Chen, M.D., M.P.H.,
co-authored the study.