D
Danish dietseeScandinavian diet
DASH diet
Definition
DASH stands for the Dietary Approaches to Stop
Hypertension. The DASH diet is based on DASH
Study results published in 1997. The study showed
that a diet rich in fruits, vegetables and low fat dairy
foods, with reduced saturated and total fat could sub-
stantially lower blood pressure. It is the diet recom-
mended by the National Heart, Lung and Blood
Institute (part of the National Institute of Health)
for lowering blood pressure
Origins
High blood pressure affects about one in four in
the United States and United Kingdom and is defined
as blood pressure consistently above 140/90 mmHg.
The top number, 140, is the systolic pressure exerted
by the blood against the arteries while the heart is
contracting. The bottom number, 90, is the diastolic
pressure in the arteries while the heart is relaxing or
between beats. The concern is the higher the blood
pressure, the greater the risk for developing heart
and kidney disease and stroke. High blood pressure
is known as the silent killer as it has no symptoms or
warning signs.
The DASH study by the National Lung, Blood
and Heart Institute (NHLBI), published in theNew
England Journal of Medicinein 1977, was the first
study to look at the effect a whole diet rich in potas-
sium, magnesiumand calcium foods, not supple-
ments, had on blood pressure.
The study involved 459 adults with and without
high blood pressure. Systolic blood pressures had to be
less than 160 mm Hg and diastolic pressures 80 to 95
mm Hg. Approximately half the participants were
women and 60% were African Americans. Three eat-
ing plans were compared. The first was similar to a
typical American diet—high in fat (37% of calories)
and low in fruit and vegetables. The second was the
American Diet, but with more fruits and vegetables.
The third was a plan rich in fruits, vegetables, and low
fat dairy foods and low fat (less than 30% of calories).
It also provided 4,700 mg potassium, 500 mg magne-
sium and 1,240 mg calcium per 2,000 calories. This has
become known as the DASH diet. All three plans
contained equal amounts ofsodium, about 3,000 mg
of sodium daily, equivalent to 7 g of salt. This was
approximately 20% below the average intake for
adults in the United States and close to the current
salt recommendations of 5–6 g. Calorie intake was
adjusted to maintain each person’s weight. These two
factors were included to eliminate salt reduction and
weight loss as potential reasons for any changes in
blood pressure. All meals were prepared for the par-
ticipants in a central kitchen to increase compliance on
the diets.
Results showed that the increased fruit and vege-
table and DASH plans lowered blood pressure, but the
DASH plan was the most effective. It reduced blood
pressure by 6 mmHg for systolic and 3 mmHg for
diastolic, those without high blood pressure. The
results were better for those with high blood pres-
sure–the drop in systolic and diastolic was almost
double at 11 mmHg and 6 mmHg respectively. These
results showed that the DASH diet appeared to lower
blood pressure as well as a 3 g salt restricted diet, but
more importantly, had a similar reduction as seen with
the use of a single blood pressure medication. The
effect was seen within two weeks of starting the
DASH plan, which is also comparable to treatment
by medication, and continued throughout the trial.
This trial provided the first experimental evidence that
potassium, calcium, and magnesium are important