Inclusion Criteria:
* Women ages 18-40 (female as defined biologically)
* Premenopausal as indicated by self-report of menstrual cycles.
* Trauma-exposed with or without PTSD. Diagnostic Criteria for both trauma exposure and PTSD will be obtained via clinical interview, medical records, and self-report.
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Diagnosis of major depression (MD).
* Comorbid Psychiatric Conditions: Participants with other anxiety disorders, and bipolar disorder without psychotic features, mild to moderate traumatic brain injury, and borderline personality disorder will be included.
* Medical records will also assist in the detection of current and lifetime comorbid psychiatric conditions.
* Any over-the-counter medications must be held for 24 hours before each testing visit.
The PTSD groups must meet DSM-5 diagnostic criteria for PTSD assessed via the CAPS 5 (at least 6 symptoms: 1 B, 1 C, 2 D, and 2 E), with a total severity score of ≥25:
We will enroll participants as long as they are stable on meds (no changes within the past 3 months). Many participants are often on psychiatric meds, but still have PTSD symptoms. It really isn't that this is an untreated sample. It is more than that it includes people actively symptomatic, regardless of current treatment. Participants will not be required to stop any psychiatric medications.
Exclusion Criteria:
* Non-biologically female people who may otherwise identify as women
* Individuals who are taking hormone replacement therapy.
* Pregnant, breastfeeding, or planning to become pregnant during the duration of the study
* Individuals taking any types of hormonal contraceptives.
* Self-reported Medical conditions: hypertension, diabetes, heart disease, vascular disease, ongoing illicit drug use, excessive alcohol use (\>2 drinks per day), hyperlipidemia, autonomic dysfunction, any serious systemic disease, gastrointestinal disorders
* Medications for PTSD or other cardiovascular diseases or any medication known to affect vascular function and central sympathetic output, such as antihypertensive medications (beta blockers, calcium channel blockers, angiotensin receptor blockers, angiotensin receptor inhibitors), corticosteroids, direct-acting vasodilators like nitrates and hydralazine, thyroid medications such as carbimazole, thyroxin.
* Psychiatric Comorbidities: Ongoing substance abuse will be excluded because of the sympathoexcitatory effect of illicit drugs such as cocaine and methamphetamines that exert a powerful pressor and direct sympathoexcitatory effect. A report of a minimum of 6 months of non-drug use (recovery) will be required for those who have a history of illicit drug use
* Psychotic and dissociative disorders will be excluded due to concerns regarding comprehension and adherence.
* The inability or unwillingness to abstain from nicotine use for at least 12 hours prior to physiologic studies (visits 1 and 2), to eliminate sympathoexcitatory effects of nicotine (half-life of 2 hours).
Any gastrointestinal complications, such as irritable bowel syndrome, and diseases such as celiac disease, irritable bowel syndrome. Any food allergy related to dietary nitrates. Any food allergy to nitrate-containing foods.