Efficacy and Safety of the DASH Diet in Adults With Moderate Chronic Kidney Disease: Pilot Study

More than two-thirds of US adults with chronic kidney disease (CKD) have uncontrolled hypertension. Both hypertension and CKD are major independent risk factors for cardiovascular disease, which is the leading cause of death in the US. Fortunately, lowering blood pressure to recommended treatment targets not only slows the progression of CKD, but also improves cardiovascular outcomes. Controlling hypertension in this patient population, however, can be quite challenging. A lifestyle modification that effectively reduces blood pressure in both pre-hypertensive and hypertensive adults is the Dietary Approaches to Stop Hypertension (DASH) diet.

The purpose of this pilot study is to (1) determine the extent to which the DASH diet lowers blood pressure in hypertensive adults with moderate chronic kidney disease (CKD) (estimated glomerular filtration rate \[eGFR\] 30-59 ml/min/1.73m2) and (2) establish that the DASH diet can be safely consumed by this patient population.

During a 7-day run-in phase, participants will first consume a control diet similar in nutrient composition to the control diet of previous DASH studies. The control diet, which is a diet typical of most Americans, is reduced in servings of fruits, vegetables, low fat dairy products and relatively high in total and saturated fat. Immediately following the run-in phase, participants will receive the DASH diet during a 14-day intervention phase. Both diets will have the same sodium content and caloric intake will be adjusted for each participant to keep weight stable. All study meals and snacks will be provided.

Eligibility Criteria:
Inclusion Criteria:

* ≥18 years old
* eGFR 30-59 ml/min/1.73m2
* SBP ≥ 130 mmHg or DBP ≥ 80 mmHg
* willing to eat one meal on-site 5 days/week

Exclusion Criteria:

* baseline potassium \>4.6 mEq/L while not taking potassium supplements (if potassium is ≥ 5.0 while taking potassium supplements, a potassium of 4.6 or less must be demonstrated off supplements
* evidence of hyperkalemia (\>5.1 mEq/L) within last 6 months
* ≥ 0.5 mg/dl increase in serum creatinine in past 6 months
* albumin-to-creatinine ratio \> 200 mg/mmol
* insulin requiring or poorly controlled diabetes mellitus
* cardiovascular event within previous 6 months
* change in anti-hypertensive medications in last 2 weeks, or anticipated medication change during study period
* unwillingness to eat only study food for 21 day study period
* unwillingness or inability to discontinue vitamin and mineral supplements or antacids containing potassium, magnesium or calcium
* use of aldosterone antagonist
* use of oral corticosteroids
* alcohol intake \>14 drinks/week
* unstable doses of psychotropics or phenothiazine
* weight reducing medications
* use of medications for erectile dysfunction during study period
* pregnant, breast feeding, or planning pregnancy during study period
* chronic disease that may interfere with participation
* history of organ transplant
* any serious illness that would interfere with participation or make DASH diet unsafe
* planning to leave the area during the study period
* significant food allergies, preferences, or dietary requirements that would interfere with diet adherence
* investigator discretion for safety or compliance reasons