The DASH Diet for Adults With Uncontrolled Asthma

Inclusion Criteria: * Ethnicity: All ethnic groups * Body mass index (BMI) 18.5-39.9 kg/m2 * Suboptimally controlled asthma: * Diagnosis of asthma on the current medical problem list * Currently prescribed at least 1 medication for the treatment of asthma * Physiological evidence of asthma with demonstrable reversibility of airway obstruction, or a specialist's confirmation of asthma diagnosis based on chart review * Documented history of high asthma-related emergency and/or inpatient encounters or reliever medication usage * Asthma Control Test: total score \<20 or item score \<3 for any of the first 4 questions regarding symptoms (3-6x/week or more), nighttime awakening (1x/week or more), interference with normal activity (at least some of the time), and rescue medication use for symptom relief (2-3x/week or more) * Kaiser member for ≥1 year * PCP approval of study screening * Able and willing to enroll and provide written informed consent Exclusion Criteria: * Intermittent asthma, defined as either seasonal asthma or (daytime asthma symptoms \<2x/week and nocturnal symptoms \<2x/month and no use of long-term control medications) * Primary diagnosis of COPD (emphysema or chronic bronchitis) on the current medical problem list or suggested by baseline spirometry and smoking history * Previous diabetes (other than during pregnancy) or diabetes diagnosed as a result of fasting blood glucose or hemoglobin A1c levels obtained at screening * Previous cardiovascular disease: e.g., coronary heart disease, cerebrovascular disease, peripheral vascular disease, heart failure, or aortic aneurysm * Diagnosis of cancer (other than non-melanoma skin cancer) that is/was active or treated with radiation or chemotherapy within the past 2 years * Inflammatory bowel disease, colostomy, malabsorption, or major gastrointestinal resection * Diagnosis of bipolar or psychotic disorder or hospitalization for psychological or emotional problems within the last 2 years * Diagnosis of a terminal illness and/or in hospice care * Fasting LDL cholesterol \>190 mg/dL, triglycerides \>500 mg/dl, fasting blood glucose \>125 mg/dl * Significant liver enzyme abnormality as indicated by AST or ALT more than 2 times the upper limit of normal or a clinical diagnosis of hepatitis * Renal insufficiency (GFR\<60 ml/min) * Current use of insulin or oral hypoglycemic agents * Use of oral corticosteroids \>5 days/month on average * Current use of medications for treatment of psychosis or manic-depressive illness * Current use of prescription or non-prescription weight-loss products or any dietary/herbal supplements and unwillingness to discontinue; * Inability to speak, read, or understand English at the 6th-grade level or above * Inability to perform pulmonary function tests by spirometry in a consistent manner * DASH concordance index \>60% * Unwillingness to modify current diet * Current or planned participation in a structured program that overtly focuses on diet and nutrition * Planning to undergo bariatric surgery during the study period * Actively attempting to lose weight, or weight change \>15 lbs during prior 3 months * Consumption of \>21 alcoholic drinks per week, or \>=6 drinks on one occasion twice or more per week, or alcoholism as determined by the Alcohol Use Disorders Identification Test * Pregnant, lactating, or planning to become pregnant during the study period * No longer a Kaiser patient or planning to transfer care out of Kaiser or to move out of the area during the study period * Family/household member of another study participant or of a study staff member * Enrolled or planning to enroll in another research study that would limit full participation in the study or confound the interpretation of the study's findings * Investigator discretion for safety or protocol adherence reasons