ABSORB (Amount of Blueberries So Older Adults Reap Benefits)

Acute Bioavailability of Berry Flavonoids and Impact on Inflammatory Biomarkers in Older Adults With Minor Depressive Symptoms: A Pilot Study

This randomized, cross-over, pilot study aims to compare preliminary impact of a standard dose of blueberry powder (24 g) vs a higher dose (48 g) on the bioavailability of flavonoids and inflammatory biomarkers in older adults with minor levels of depressive symptoms.

Blueberries are a rich source of anti-oxidants and dietary fiber, and are recommended to consume as a part of a healthy diet. Regular consumption of blueberries as a source of dietary antioxidants may be an effective way to lower inflammation in older adults, who commonly have higher levels of inflammatory markers. However, older adults typically have a decreased efficiency of nutrient absorption and may need a higher dose of blueberries to absorb enough of the flavonoids needed to reap their benefits on inflammation. Thus, it is important for preliminary studies to pre-determine an appropriate dose of blueberry flavonoids specifically for older adults. This study aims to evaluated the preliminary impact of freeze-dried blueberry powder consumption on flavonoid bioavailability and inflammatory biomarkers in older adults. This will be an individual-level, unblinded, randomized, cross over pilot study in 6 older adults with minor levels of depressive symptoms. Eligible participants will collect a 24 hour urine sample, and then come in for the baseline assessments and provide a blood sample. Next they will be randomized to consume either the higher dose (48 g/day, equivalent ~ 2 cups of fresh blueberries) or the lower dose (24 g/day, equivalent ~1 cup of fresh blueberries) for 3 days. After 3 days they will begin collecting a 24 hour urine sample, and come in to repeat the baseline assessments and provide a blood sample. After a two week wash out period, participants will repeat the same baseline and follow-up assessments while consuming the other powder.

Inclusion Criteria: Men and women aged 65 years and older Minor levels of depressive symptoms (center for epidemiological studies depression scale, ≥4 and <16 points) Exclusion Criteria: Unwilling to follow the study protocol Cognitive impairment (assessed via the telephone Montreal Cognitive Assessment) defined as individuals scoring <19) Self-reporting a history of major depression, bipolar, schizophrenia, or other psychotic or neurologic disorders Self-reporting of history gastro-intestinal diseases/conditions e.g., of bowel resection, inflammatory bowel disease/syndrome, Celiac disease Self-reporting immune disorders, e.g., rheumatoid arthritis, cancer, and other immunocompromising conditions Self-reporting history of type 1 or type 2 diabetes Self-reporting any history of substance or alcohol use disorder Allergy to blueberries Self-reporting use of anti-inflammatory (e.g., fish oil or non-steroidal anti-inflammatory drugs) or immune-suppressant drugs Are excessive tea or coffee consumers (e.g., >3 cups/day) Recent and consistent use of antibiotics or pro-biotics Currently taking or advised during the intervention to take anti-depressants Current homicidal or suicidal ideation (assessed via the P4 Suicidality Screener