Castlewood Eating Disorder Treatment Center Blog

Serotonin, Fluid and Probiotics

Tammy Beasley, RDN, CEDRD shares her answers to two questions we received in response to her March Webinar. Join us the 2nd Tuesday of every month for her insightful updates about nutrition and dietetics in the field of Eating Disorders. “Does serotonin increase or decrease fluid in the gut?” This is another great question from a participant in Castlewood’s “The Gut Brain and Eating Disorders: Nutrition Therapy in the Healing Process” webinar but one without definitive answers in relationship to eating disorders specifically. Fact #1: Most of the body’s serotonin is found in the gastrointestinal tract and is known to regulate secretory, motility and sensory events in the gut.  Fact #2: If we eat something that is toxic or irritating to our gut, more serotonin is produced within the gut to increase the transit time and expel the irritant.  If serotonin regulates bowel function and movement as well as the expelling of food irritants, and fluid is a critical component of bowel movement and vomiting itself, it makes sense that a connection between eating disorder behaviors and resulting fluid imbalances exists but research specific to eating disorders is lacking. These are the questions that will open the door to future research, and the reason why the answers we discover will be so beneficial to the field of eating disorders in which gut and mental health are so intertwined. It’s important to know and also encourage our clients that a March 2016 published systematic review of gastrointestinal complications associated with anorexia nervosa suggests that most GI complications resolve with the refeeding and cessation of ED symptoms. (Norris ML, Harrison ME, et al. Gastrointestinal complications associated with anorexia nervosa: a systematic review. IJED 49(3): 216-237; 2016.) “What should we look for in a probiotic?” Most of the studies on probiotics are small in size, of short duration, and have significant design flaws. However, growing evidence is favoring Bifidobacterium infantis 35624 as the “probiotic du jour” showing most promise in regards to gut health. Best advice includes the following: Look for a probiotic with colony forming units (CFUs) in the billions, and check the expiration date to ensure viability. Popular choice favors refrigerated probiotics.  Depending on the condition, a standard dose of probiotic is between 1 and 5 billion live organisms daily. Probiotics can cause bloating and gas in some, and people with compromised immune systems, such as HIV/AIDS or who are taking medications that weaken the immune system, should avoid probiotics altogether. From an informal survey of respected physicians and dietitians currently practicing in the field of eating disorders, all recommend probiotic supplements to their clients and encourage food-based probiotics like yogurt (discussed in last month’s blog) as well. Be sure to join us for next month’s blog:  Practical Nutrition Education Tools to Neutralize Food Shame