The study investigators will recruit a generally healthy sample of 112 black and white adults
from Birmingham, AL to participate in a 28-day randomized, controlled feeding study.
Participants will be randomized to receive either the DASH diet or a standard American diet.
All meals will be provided by the study. Fecal samples will be collected at multiple time
points before, during, and after the dietary intervention and will be analyzed using PCR to
amplify the V4 region of the 16S rRNA gene and to sequence bases using the MiSeq platform.
Sequenced data will then be analyzed using QIIME. The investigators hypothesize that
participants receiving the DASH diet will have a greater increase in alpha diversity and
greater changes in abundances of CRC-associated microbes than participants receiving the
standard American diet. The investigators will also evaluate functional-level markers
including bile acid and short chain fatty acid (SCFA) production and inflammatory markers. If
the investigator's hypothesis is supported, they expect to see reduced production of
secondary bile acids (e.g., deoxycholic acid), greater SCFA production (e.g, butyrate), and
reduction in gut and systemic inflammation (e.g, calprotectin, IL-6) among participants
receiving the DASH diet compared to the standard American diet. The investigator's findings
will provide preliminary evidence for the DASH diet as an approach for cultivating a
healthier gut microbiota across racially diverse populations. These findings can impact
clinical, translational, and population-level approaches for modification of the gut
microbiota to reduce risk of chronic diseases like CRC.