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Hypertension No Match for DASH Diet

U-M study shows drop in blood pressure after just 21 days

Hypertension was no match for the DASH diet during a University of Michigan Cardiovascular Center study in which patients with a certain type of heart failure were given heat-and-serve low-sodium (low-salt) meals for three weeks.

Tipped over salt shaker

Hypertension was no match for the DASH diet during a study in which patients with a certain type of heart failure were given heat-and-serve low-sodium (low-salt) meals for three weeks.

In just 21 days of following a low-sodium Dietary Approaches to Stop Hypertension (DASH) eating plan, patients with  “diastolic” heart failure saw a drop in blood pressure similar to taking an anti-hypertension medicine. Some patients were able to cut back on their diuretics and anti-hypertensives.

Diastolic heart failure (a type of heart failure that occurs even though the heart’s muscle-pumping function is not weakened), happens when the heart becomes stiff and does not relax enough between beats. This condition makes up more than half of older adults with heart failure, but has no standard treatment. University of Michigan cardiologist Scott L. Hummel, M.D., M.S, wondered if, based on animal studies, diet could make a big difference for these patients.

Study participants ate prepared meals that matched the DASH plan

The study included 14 heart failure patients, six with diabetes. Most of them were taking three or more blood pressure medicines, and 10 patients had a prior hospitalization for worsening heart failure.

All agreed to keep food diaries and eat only the meals prepared for them in the metabolic kitchen at the University of Michigan Clinical Research Unit. The meals, which could be picked up and heated at home, matched the DASH diet eating plan, which is high in potassium, magnesium, calcium and antioxidants and is recommended for hypertension treatment by the National Institutes of Health and the American Heart Association.

The study diet also contained a daily sodium intake of no more than 1,150 milligrams. That’s much lower than what adults in the United States usually eat – about 4,200 mg a day in men, and 3,300 mg a day in women.

“The key to reducing salt intake is making wise food choices. Only a small amount of sodium that we consume comes from the salt added at the table, and only small amounts of sodium occur naturally in food. Processed foods account for most of the sodium Americans consume,” Hummel says.

For example, a half-cup of fresh or frozen vegetables, cooked without salt, has 1 to 70 mg of sodium compared to a whopping 330 mg of sodium in a can of tomato juice. Just one meal from a fast food restaurant typically contains more sodium than AHA recommends for an entire day.

Weight loss an added bonus

Doctors have long known that the low-sodium DASH diet can lower blood pressure in salt-sensitive patients. The University of Michigan study, although small, showed the DASH diet can reduce blood pressure and oxidative stress in hypertensive patients with heart failure. As a bonus, patients in the study also lost an average of 3.8 pounds.

“Our work suggests diet could play an important role in the progression of heart failure, although patients should always talk to their doctor before making major dietary changes,” Hummel says.  “We’re excited to confirm these results in longer-term studies that also help us understand the challenges patients face when they try to improve their eating habits.”

Learn more

Check out a one-day DASH menu.

Download PDF: Your Guide to Lowering your Blood Pressure with DASH

Read the study: Low-Sodium Dietary Approaches to Stop Hypertension Diet Reduces Blood Pressure, Arterial Stiffness, and Oxidative Stress in Hypertensive Heart Failure With Preserved Ejection Fraction

The original article appeared in Hypertension, a journal of the American Heart Association.