Salt showdown: new study puts blood pressure to the test

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Phase 1: Salt Sensitivity Screening Inclusion: 1. Signed informed consent for the salt sensitivity test. 2. Systolic blood pressure between 110-159 mmHg and diastolic blood pressure between 70-99 mmHg. 3. Not taking any antihypertensive medication, or have had a stable antihypertensive regimen for the past three months and agree not to adjust their medication during the study period. 4. Able to comply with consuming the study-provided diet throughout the study period. Exclusion: 1. Special dietary requirements, such as allergies to common foods (e.g., eggs, seafood, peanuts), or conditions like asthma, irritable bowel syndrome, lactose intolerance, chronic kidney disease stage 4 or higher, history of gastrointestinal surgery, or special dietary needs due to other illnesses, surgery, or weight loss. 2. Diagnosed with chronic diseases: any malignancy with a life expectancy of less than one year; chronic heart failure, severe depression or other mental disorders, long-term bedridden status, or mobility limitations. 3. Experienced acute myocardial infarction or stroke within the past 6 months. 4. Acute illnesses such as upper respiratory tract infection, fever, or severe diarrhea that have not yet resolved. 5. Alcohol abuse. 6. Pregnant or breastfeeding women, or women planning to become pregnant. 7. Individuals who are deaf, mute, or have cognitive impairments that hinder communication. Phase 2: N-of-1 Trial Inclusion: 1. Classified as salt-sensitive or salt-resistant through the Phase 1 screening: 2. Salt-Sensitive (SS) Group: Participants with a change in mean arterial pressure (ΔMAP) ≥ 5 mmHg and in the upper 1/6 of the distribution of ΔMAP from the salt sensitivity test. 3. Salt-Resistant (SR) Group: Participants with a change in mean arterial pressure (ΔMAP) \< 5 mmHg and in the lower 1/6 of the distribution of ΔMAP from the salt sensitivity test. 4. Signed informed consent for the n-of-1 trial. Exclusion: 1. Failed to complete the salt sensitivity test as required, or consumed less than 80% of the study-provided meals during the salt sensitivity test (i.e., fewer than 34 meals over 14 days). 2. Experienced adverse events during the salt sensitivity test that, in the investigator's judgment, make it inappropriate to continue in the study.