has no restrictions but follows standard dietary guide-
lines for the general public.Precautions
Adding highfiberfoods to the diet should be done
gradually to avoid side effects such as gas, bloating,
and diarrhea. It is important to increase fluid at the
same time, as fiber drawswaterinto the bowel. High
fiber with inadequate fluid can cause hard stools and
constipation.
Increasing fruits and vegetables increases the
potassium content of the diet. For healthy people with
normal kidney function, a higher potassium intake
from foods does not pose a risk as excess potassium is
excreted in the urine. However, individuals whose uri-
nary potassium excretion is impaired, such as those
with end-stage renal disease, severe heart failure, and
adrenal insufficiency may be at risk of hyperkalaemia
(high levels of potassium in the blood). Hyperkalaemia
may cause cardiac arrthymias (irregular heart beat),
which could be serious. Some common drugs can also
decrease potassium excretion. Individuals at risk
should consult a doctor before staring the DASH diet,
as higher potassium intakes in the form of fruit and
vegetables may not be suitable. Care should also be
taken with potassium containing salt substitutes.Risks
Currently, there are no known risks associated
with the DASH diet. However, the long-term effects
of the diet on morbidity and mortality are still
unknown.Research and general acceptance
Studies over the years have suggested high intakes
of salt play a role in the development of high blood
pressure so dietary advice for the prevention and low-
ering of blood pressure has focused primarily on reduc-
ing sodium or salt intake. A 1989 study looked at the
response an intake of 3-12 g of salt per day had on blood
pressure. The study found that modest reductions in
salt, 5-6 g salt per day caused blood pressures to fall in
hypertensives.Thebesteffectwasseenwithonly3gof
salt per day with blood pressure falls of 11 mmHg
systolic and 6 mmHg diastolic. More recently, the use
of low salt diets for the prevention or treatment of high
blood pressure has come into question. The Trials of
Hypertension Prevention Phase II in 1997 indicated that
energy intake and weight loss were more important than
the restriction of dietary salt in the prevention of hyper-
tension. A 2006 Cochrane review, which looked at the
effect of longer-term modest salt reduction on bloodpressure, found that modest reductions in salt intake
could have a significant effect on blood pressure in
those with high blood pressure, but a lesser effect on
those without. It agreed that the 2007 public health
recommendations of reducing salt intake from levels
of 9-12 g/day to a moderate 5-6 g/day would have a
beneficial effect on blood pressure and cardiovascular
disease.
The effectiveness of the DASH diet for lowering
blood pressure is well recognized. The 2005 Dietary
Guidelines for Americans recommends the DASH
Eating Plan as an example of a balanced eating plan
consistent with the existing guidelines and it forms the
basis for the USDA MyPyramid. DASH is also rec-
ommended in other guidelines such as those advocated
by the British Nutrition Foundation, American Heart
Association, and American Society for Hypertension.
Although results of the study indicated that reduc-
ing sodium and increasing potassium, calcium, and
magnesium intakes play a key role on lowering blood
pressure, the reasons why the DASH eating plan or the
DASH-Sodium had a beneficial affect remains uncer-
tain. The researchers suggest it may be because whole
foods improve the absorption of the potassium, cal-
cium and magnesium or it may be related to the cumu-
lative effect of eating these nutrients together than the
individual nutrients themselves. It is also speculated
that it may be something else in the fruit, vegetables,
and low-fat dairy products that accounts for the asso-
ciation between the diet and blood pressure.
The Salt Institute supports the DASH diet, but
without the salt restriction. They claim that the DASH
diet alone, without reduced sodium intake from manu-
factured foods, would achieve the desired blood pres-
sure reduction. Their recommendation is based on the
fact that there are no evidence-based studies supporting
the need for dietary salt restriction for the entire pop-
ulation. The Cochrane review in 2006 showed that mod-
est reductions in salt intake lowers blood pressure
significantly in hypertensives, but a lesser effect on indi-
viduals with normal blood pressure. Restriction of salt
for those with out hypertension is not recommended.
There is continued call for the food industry to
lower their use of salt in processed foods from govern-
ments and health associations. These groups claim if
the reduction of intake to 6 g salt/day is achieved by
gradual reduction of salt content in manufactured
foods, those with high blood pressure would gain sig-
nificant health benefit, but nobody’s health would be
adversely affected. In 2003, the UK Department of
Health and Foods Standards Agency, several leading
supermarkets and food manufacturers set a target forDASH diet