Manual of Clinical Nutrition

Hypertension

Manual of Clinical Nutrition Management III- 66 Copyright © 2013 Compass Group, Inc.

Table III- 16 : Evidence Supporting Lifestyle Modifications to Manage Hypertension
Lifestyle Modification
Factor

Rationale

Adequate potassium
intake

Observational studies suggest that increased consumption of potassium is associated

with a lower incidence of stroke (17). High potassium intake may also be protective

against hypertension (2,13,22). The diet should emphasize the consumption of foods

rich in potassium, except when contraindicated (eg, patients who receive

angiotensin-converting enzyme inhibitors or who have renal insufficiency). The

JNC 7 does not specify a potassium intake level. However, the JNC 6 recommended a

potassium intake of 3,510 mg/day (90 mmol/day) from food sources such as fresh

fruits and vegetables. The latest DRIs for potassium have been increased to 4,500

mg/day for adults to provide a protective effect against hypertension (23).

Potassium intakes that do not meet the DRIs are associated with increased blood

pressure (Grade II) (12). The DASH eating plan, which significantly reduces blood

pressure, provides 4,700 mg/day of potassium based on a 2,000 kcal combination

diet (13,19,20,24). The Dietary Guidelines for Americans suggests that individuals who

have hypertension, African Americans, and middle-aged and older adults should

meet the potassium recommendation of 4,700 mg/day from food sources (21). The

best sources of potassium are fruits from vines, leafy green vegetables, and root

vegetables (21). Although meat, milk, and cereal products contain potassium, the

form of potassium in these foods is not as readily absorbed (21).

Adequate magnesium
intake

Because of its vasodilative properties, magnesium may have beneficial effects on

hypertension (17). However, no evidence suggests that patients should increase their

magnesium intake beyond the DRI (Grade II) (2,12,22). The DASH eating plan, which

significantly reduces blood pressure, provides 500 mg/day of magnesium based on a

2,000 kcal combination diet (24). Dietary patterns that do not meet the DRI for

magnesium may be associated with increased blood pressure (Grade II) (12).

DASH eating plan The DASH clinical study demonstrated that a diet (referred to as a combination diet)
that is rich in fruits and vegetables (five to ten servings) and low-fat dairy food and
reduces the intake of saturated fat (6%), total fats (<27% energy), and sodium
(<2,400 mg/day and 1,500 mg/day) significantly lowers blood pressure (Grade I)
(12,13,19-25). The DASH eating plan that limits sodium intake to 1,500 mg/day provides
the greatest blood pressure reductions (13,19). Following the DASH eating plan is
associated with an 8 to 14 mm Hg reduction in systolic blood pressure (13,19). The
DASH 2,000 kcal combination diet also provides 31 g/day of fiber (21). The JNC 7 and
the Academy of Nutrition and Dietetics recommend the DASH eating plan for the
treatment of hypertension (Grade IV) (2,12). The serving sizes from the Dietary Guidelines
for Americans are used as the reference guide in the DASH eating plan (21). The DASH
eating plan provides 2,000 kcal/day, however it can be modified to meet lower or
higher energy needs (26). (Refer to Tables III- 17 and III- 18 for details regarding the
DASH eating plan (23, 26).

Table III- 17 : DASH Eating Plan (26)

Food Group Daily Servings Serving Sizes Examples and Notes Significance to the

DASH Eating Plan

Grains and grain

products

Seven to eight One slice of bread

1 oz dry cereala^

½ cup cooked rice,

pasta, or cereal

Whole wheat bread,

English muffin, pita

bread, bagel, cereals,

grits, oatmeal, crackers,

unsalted pretzels and

popcorn

Major source of

energy and fiber

Select unsalted or

lower sodium

products