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Sarah Reyes, Ph.D. Candidate in Nutritional Sciences at Cornell University and NIH Predoctoral Trainee in Translational Research in Nutrition

Sarah Reyes received her B.A. in Interdisciplinary Studies – International Studies and Human Nutrition and her M.S. in Animal Science from the University of Idaho and is completing her Ph.D. studies in the Human Nutrition Program at Cornell University’s Division of Nutritional Sciences. Sarah is an NIH predoctoral trainee on a translational research in nutrition training grant of which, until recently, former ASN president Patrick Stover was the PI. Sarah has been an ASN member since 2009 and holds the position of Secretary for the International Society for Research in Human Milk and Lactation’s Trainee Interest Group, an ASN partner organization.

1. How did you first get involved in nutrition science and research?

I come from Idaho, a rural state with high rates of chronic diseases such as diabetes and hypertension. I originally wanted to become a physician because access to quality medical care in Idaho is relatively limited for poor and rural populations. I chose to study International Studies and Human Nutrition to give me breadth of knowledge that I thought would position me competitively for acceptance into medical school. However, the more I learned about the cycles of poverty and oppression in my International Studies courses and the power of nutrition and exercise to prevent and even treat chronic disease, I realized quickly that my passion was to empower people like me—the daughter of a mixed-race couple from a blue-collar family in poor, rural America—to prevent chronic disease. I became passionate about public health and how to disrupt the systems in place that sustain cycles of poverty and oppression. I recognized that my overlapping interests in basic science and public health could be a powerful tool to create evidence-based recommendations to empower disadvantaged and marginalized members of our society achieve better health outcomes. (At the time I wasn’t aware of the term translational research, but ultimately that’s what I pursued). My interest in nutrition, specifically, was inspired by my undergraduate courses which taught me that my grandmother’s type II diabetes and neuropathy were consequence of years of subsisting on a diet nearly void of fresh fruits and vegetables and eating too much white bread, white sugar, and white potatoes (I mean it was rural Idaho—yes, the stereotype applies).

2. Tell us about your current position and the research activities in which you are involved.

I’m a PhD candidate in the Division of Nutritional Sciences at Cornell University. Kathleen Rasmussen, ScD, RD is the Chair of my doctoral committee, and I collaborate with the laboratories of Anthony Hay, PhD, at Cornell University, Mark McGuire, PhD, at the University of Idaho, and Shelley McGuire, PhD at Washington State University. In the spirit of translational research, I was intent on using basic science to advance a public health initiative for my doctoral research. I was able to leverage my Chair’s interest in women’s real-life experiences with pumping and feeding expressed breast milk with the combined expertise in microbiology and lactation physiology of my collaborators. I was particularly interested in the discordance between the way expressed milk was collected in studies cited in current recommendations for handling and storage of expressed milk at home and the way expressed milk is collected in real-life. Specifically, most studies collect milk aseptically whereas real-life is messy. Women often have to pump their milk in less than ideal conditions such as in restrooms, vehicles, and other public spaces. Plus, expressed milk is often stored at multiple temperatures and poured into several different containers. My doctoral research has focused on characterizing and comparing the human milk microbiome in real-life conditions v. aseptic collection and identifying sources of and factors associated with bacterial contamination in expressed milk. We conducted a randomized trial to do this research and I’m just finishing up the analyses of this work. Our results not only fill a critical gap needed to improve existing recommendations for handling and storage of expressed milk at home, but it also opens up questions about how differential exposure to microbes from breast milk influence the infant gastrointestinal microbiome and health outcomes. I’m excited to share some of our results for the first time at Nutrition 2018!

3. You are a student at a prestigious university, a mother of two, and pregnant?! How do you do it?

I get that question a lot! In fact, I made a YouTube video of a day in my life to give others a glimpse of how I make it work. First, I have a fully supportive and loving husband, Paul Reyes. His commitment to helping me achieve this goal is undoubtedly a huge reason why I have been able to pull off school and kids simultaneously. My hat goes off to all the single, working moms out there. I don’t know how they do it! Second, having kids has pushed me to become more intentional about my goals, to prioritize my daily, weekly, monthly, and yearly tasks needed to accomplish those goals, and to manage my time so I can maintain the energy and enthusiasm needed to be productive over extended periods of time while still being present at home.

4. What do you feel are the biggest challenges facing nutrition researchers today? 

My biggest concern for nutrition researchers is public trust. Without trust, individuals will not heed recommendations. Especially where I’m from, many are leery of dietary recommendations because some have changed drastically over time (think cholesterol and eggs). Drastic changes in recommendations are perceived as “scientists don’t know what they’re doing.” Plus, policies enacted to ensure healthy eating is equitable (e.g., trans-fat bans, soda size restrictions in NYC, school lunch policies limiting access to sugary and salty foods) are seen as attacks on individual rights and freedoms, which fuels distrust in recommendations. I think a combination of the use of rigorous study methods to produce quality science along with nutrition scientists being more vocal on social and other media platforms can help improve public trust.

5. Is there anything else you’d like to tell ASN members, especially students?

Know what your objectives are and be intentional on dedicating time to those. Expose yourself to as many learning opportunities as you can to gain breadth of knowledge and experience. For example, take a short-course on equity either online, at your university, or at another university. Become involved in things that matter to you both professionally and personally! This will keep you enthusiastic and motivated about your research and help you live a healthier life. Stay open-minded and remain objective in your pursuit of science. Finally, find a good mentor and a good advocate. A good mentor will help you learn how to conduct rigorous science and sharpen the skills you need to meet your own personal objectives. An advocate is someone who is respected in your field that can help you find and avail on opportunities that will help you achieve your goals.

[Learn more about ASN student membership here]

Sarah Reyes’ primary interests are the developmental origins of health and disease and finding equitable solutions to empower disadvantaged and marginalized populations achieve better health outcomes. Sarah’s interests are focused on the mother-infant dyad and, in particular, the breastfeeding relationship. Most recently, Sarah’s work has focused on characterizing the bacterial communities in breast milk pumped in real-life conditions. Sarah has conducted research in mammalian and bacterial cell culture, biochemical analyses, epidemiology, and microbiome research. In addition to her research interests, Sarah is interested in opportunities to use her knowledge to serve others. She recently attended the Make the Breast Pump Not Suck Hackathon where she helped design a study to evaluate the efficacy of hand expression on milk volume for incarcerated women in New Mexico. Visit her video, A Day in the Life of a PhD Mom | Ivy League, Kids, and Pregnancy.

By Allison Dostal, PhD

Gastrointestinal problems are one of the most common unpleasant issues that we all experience at some time or another. But what if your upset stomach wasn’t just a passing discomfort? What if severe abdominal pain, cramping, fatigue, and diarrhea became more of your norm and less of a passing annoyance? For more than 1.4 million Americans, these symptoms typify their experience with inflammatory bowel disease (IBD), a disorder characterized by chronic inflammation of the gastrointestinal (GI) tract. The specific cause (or causes) of IBD remain unknown, but one leading hypothesis is that the bacteria that inhabit our GI system – termed the gut microbiome – play a central role. In this post, we’ll take a closer look at this condition and highlight research aimed at elucidating the impact of the microbiome in IBD development, progression, and treatment.

Characteristics, Diagnosis, and Treatment of IBD

Inflammatory bowel disease is unique in that its symptoms vary from person to person, and an individual’s own experience with their condition can differ markedly from another affected person. Most people are diagnosed with one of the two most common types of IBD, which are ulcerative colitis (UC) and Crohn’s disease (CD). The primary distinguishing factor between the subtypes is that in UC, symptoms are limited to the colon. In contrast, any part of the GI tract – from the mouth to the anus – can be affected in CD. In addition, UC only involves the innermost layer of the colon, while CD can extend deeper into the cell layers of the GI tract. Lastly, in CD, the inflammation can “skip”, leaving normal areas between patches of affected GI tract.

Making a clear IBD diagnosis isn’t always as easy as meeting – or not meeting – these criteria. There is no gold standard available for a clear-cut diagnosis, and 5-15% of cases do not meet strict criteria for either UC or CD. These patients fall into the “IBD type unclassified” (IBDU) group. And in up to 14% of patients, the diagnosis changes over time. Despite the difficulty in specific diagnosis, all subtypes of IBD have one strong feature in common: an abnormal response by the body’s immune system. The immune system is composed of various cells and proteins that usually protect our bodies from infection. However, in people suffering from IBD, the immune system reacts inappropriately, and mistakes benign or beneficial cells and bacteria for harmful foreign substances. When this happens, the immune system produces an inflammatory response within the GI tract and produces the symptoms of IBD. This adverse reaction is termed a “flare”, and can result in symptoms such as abdominal pain and cramping, diarrhea, fever, and blood in the stool. People with IBD often have deficiencies in vitamins, minerals and macronutrients stemming from loss of appetite, reduced food intake, and malabsorption from the GI tract. The lack of nutrients can lead to worsening of symptoms or development of new complications.

Treatment for IBD is centered around two goals: achievement of remission and prevention of flares. Anti-inflammatory drugs such as aminosalicylates and antibiotics are often the first line of treatment, and can be followed by corticosteroids, immunomodulators, and/or biologic agents. In severe cases, removal of the affected part of the GI tract is needed if a patient is not responsive to other treatments.

The Role of the Microbiome in IBD

In recent years, it has become clear that the microbes in our gut have a key role in IBD, but the bacteria involved and their associated functions remain largely unknown. An imbalance of the normal gut bactera due to loss or overabundance of certain species is important in the persistence of the inflammatory responses seen in IBD. The role of the gut microbiota in IBD pathogenesis has been demonstrated by studies showing that antibiotic use can reduce or prevent inflammation – antibiotics work by reducing the number and types of bacteria found in the gut, therefore killing microbes that are causing IBD symptoms. Also, results from studies with UC patients who underwent a transfer of stool collected from healthy donors – called a fecal microbiota transplant – had notable disease remission. However, results have not been consistent between studies, due to differences in populations studied, official diagnosis, treatment methods and doses, and methods of assessing study endpoints. Therefore, no consensus on the microbiome’s relationship to IBD has been reached.

Research Endeavors

As you can imagine, the combination of unpleasant, potentially severe symptoms and an uncertain diagnosis or treatment can result in significant stress on IBD sufferers, their caregivers, and health care providers. The scientific efforts dedicated to identifying causes and cures for IBD have rapidly expanded in recent years due to advances in technology that allow researchers to work toward refining a clear diagnosis, map specific gut bacteria associated with disease development and symptoms, and identify defined targets for therapy. One of these initiatives is the Crohn’s and Colitis Foundation of America (CCFA) Microbiome Initiative, which is dedicated to understanding the role of the gut microbes in IBD, IBD families, and disease flares. Thus far, there are 7 active projects and 30 published manuscripts stemming from the Initiative, which have determined that different subsets of IBD are characterized by signature bacterial compositions and that people carrying different IBD genes have different microbiome compositions, among other accomplishments.

Other organizations are also supporting IBD research endeavors, including the Kenneth Rainin Foundation, whose Innovator Awards program provides $100,000 grants for one-year research projects conducted at non-profit research institutions, and the NIH’s Human Microbiome Project, which has funded several projects aimed at genetic and metabolomic elucidation of risk for Crohn’s disease. Several randomized trials are ongoing at this time, and their results will inform future directions for diagnosis, treatment, and eventual resolution of IBD.

References

Borody TJ, Warren EF, Leis SM, Surace R, Ashman O, Siarakas S. Bacteriotherapy using fecal flora: toying with human motions. J Clin Gastroenterol.2004;38(6):475–483.

Bull MJ, Plummer NT. Part 1: The Human Gut Microbiome in Health and Disease. Integr Med. 2014 Dec; 13(6):17-22.

Crohn’s and Colitis Foundation of America:http://www.ccfa.org/

Swidsinski A, Weber J, Loening-Baucke V, Hale LP, Lochs H. Spatial organization and composition of the mucosal flora in patients with inflammatory bowel disease.J Clin Microbiol. 2005;43(7):3380–3389.

Tontini GE, Vecchi M, Pastorelli L, Neurath MF, Neumann H. Differential diagnosis in inflammatory bowel disease colitis: state of the art and future perspectives. World J Gastroenterol. 2015 Jan 7;21(1):21-46.

By Teresa L. Johnson, MSPH, RD

W. Allan Walker, MD, and Emeran Mayer, MD chaired a symposium during ASN’s Scientific Sessions and Annual Meeting on March 30 that considered the role the gut microbiome plays in human behavior.

Mark Lyte, PhD, MS, a professor at Texas Tech University, provided insights into aspects of gut-brain communication pathways. He introduced the idea that gut bacteria, as neuroendocrine organisms, are more interactive with their human hosts than previously believed. Lyte then pointed out that the gut is highly innervated, and information flows in a bi-directional but asymmetrical fashion between the gut and the brain, with as much as 90 percent of the information flowing from the gut. He suggested that neuroendocrine chemicals naturally present in foods might influence gut bacteria responses, and mechanisms that were previously considered immunological might be neuroendocrinal instead. The take-home message, Lyte said, was that these food-derived neurochemicals, when absorbed in gut, likely interact with the microbiota. In response, the microbiota produce neurochemicals that affect behavior and cognition in a sort of feedback loop. He cautioned that much of the data are correlational, and causation cannot be assigned.

Sarkis Mazmanian, PhD, California Institute of Technology, focused his remarks on specific molecular communications between the gut and brain. He explained that our bodies are in contact with trillions of microbes. “This microbial fingerprint has effects on many aspects of our biology,” said Mazmanian. He noted that in recent decades, the prevalence of autism spectrum disorder (ASD) has increased dramatically, and he presented data demonstrating that in rodents, maternal immune activation during pregnancy yields offspring with ASD and dysbiosis, suggesting a possible gut-microbiome-brain connection in ASD.

Premysl Bercik, MD, a gastroenterologist and associate professor at McMaster University, noted that while individuals with inflammatory bowel disorders commonly have abnormal gut function and low-grade inflammation, they also experience psychiatric comorbidities such as depression, stress, and anxiety. The trigger for this chain of events has not been identified, Bercik said, but some have hypothesized that infections or abnormal gut flora might be responsible. He then presented data from animal models that demonstrate the bi-directional communication between the gut and brain, and described recent research indicating that both microbial and host factors influence behavior.

Mayer, a professor at the David Geffen School of Medicine at UCLA, began his presentation with a historical perspective on the perceived gut-brain connection, which dates back several millennia. He then described notable limitations to using rodent models to study the gut-brain connection due to structural differences between rodent and human brains, and added that the germ-free mouse, a common model for understanding gut microbiome function, introduces many confounders into the research due to its altered metabolism. Mayer presented data that indicate that pre- and post-natal stress alters the gut microbiome in animals, as evidenced by both behavioral and biological changes, and he raised the idea that the gut microbial organization might influence brain structure. Attempts to modulate behavior with probiotics are promising, Mayer said, because intake blunts the reactivity of several internal organs, including those in the gut. Mayer concluded his presentation by cautioning that although enthusiasm to extrapolate findings from rodent models to human conditions including obesity, autism, and others is high, many questions remain about the role the gut microbiome plays in human health.