When an individual is diagnosed with breast cancer, there is typically a delay before treatment begins. Katrine Whiteson, PhD, Samueli Scholar and associate professor of molecular biology and biochemistry, wants to know whether a high-fiber diet intervention within this crucial timeframe can help improve patients’ gut microbiomes – and therefore improve their treatment outcomes.
This year, Whiteson has been conducting the “Priming Breast Cancer Survivors for Success with High Fiber Diets to Promote Microbiome and Immune Health” study. Collaborators include fellow Samueli Scholar Angela Fleischman, MD, PhD, associate professor of hematology oncology in the UCI School of Medicine; Laura Esserman, MD, director of the Carol Franc Buck Breast Care Center at UCSF; Karen Lindsay, PhD, RDN, Early-Career Samueli Endowed Chair and registered dietitian nutritionist at the Samueli Institute; Karen Lane, MD, surgeon at UCI Health Pacific Breast Care Center; and technology company BiomeSense.
Study participants engage in a three-week regimen in which they record their daily food intake and submit 12 fecal samples and four fingerprick blood samples. Participants maintain their normal diet for the first week. For the next two weeks, they increase their fiber intake by consuming one daily serving of chia seeds or chia powder. Participants also complete pre-intervention, post-intervention, and one-year follow-up surveys.
Whiteson chose to work with people who have been off active therapy for a year or more, with the exception of hormone therapy. Before working with newly diagnosed patients, who are already facing a particularly stressful situation, she wanted to first gain insights from the successes and challenges of diet changes faced by people further in their cancer journey. Then, later down the line, she can leverage those learnings to optimize the diet intervention for patients in between diagnosis and treatment – a critical period that offers a unique opportunity for dietary changes to potentially influence treatment outcomes.
The study also offers optional virtual nutrition education classes, in which participants learn about more ways to increase their fiber intake and cook high-fiber recipes with Samueli Institute Executive Chef Jessica VanRoo. Recipes include Thai-spiced cashew quinoa salad, chocolate black bean cookies, and broccomole. Though these classes are not required, Whiteson said the turnout has been a success. Participants enjoyed sharing creative ways to use the chia seeds and appreciated having the opportunity to ask questions regarding bio sample collection and microbiome health. People even went deeper and asked about Dr. Whiteson’s insights on prediabetes and carbohydrates, she said.
“They’ve just been thrilled to have a chance to learn more,” Whiteson said.
Fiber is an essential component of a healthy diet. However, about 95% of people do not eat the recommended 25-30 grams per day. Bridging this dietary gap and understanding its impact on the microbiome is important, especially for cancer survivors, for whom treatment success and recurrence remain significant concerns.
Whiteson said she anticipates that the study will produce “one of the best longitudinal datasets in response to change for the microbiome.” As far as what she and her collaborators expect to see in the data, Whiteson pointed to one key area: “Usually when people eat more fiber, the bifidobacteria content of their gut microbiome increases.” She said she looks forward to seeing what else can be gleaned from the dataset.
Whiteson is hoping to set the stage for larger studies, and not just with breast cancer. She also wants to look at how a high-fiber diet intervention can affect cardiovascular disease, and more.
“What’s next is learning more about how the microbiome relates to treatment outcomes in breast cancer and learning more about how to help with dietary interventions to improve treatment outcomes,” Whiteson said.
