Patients undergoing intensive conditioning regimens for HSCT who develop a period of cytopenia have an increased risk for developing a food-related infection from bacteria, yeasts, molds, viruses, and parasites. To help prevent food-related infections, many institutions have implemented some form of low-bacteria or low-microbial diet. Variations include sterile diet, well-cooked foods only, or a modified house diet which omits fresh fruits and vegetables from an otherwise regular diet. While the effect of a low-bacteria diet on preventing infection is unknown, HSCT patients who are neutropenic should avoid foods associated with increased infection risk. More studies are needed to determine the safety, efficacy, and necessity of a low-bacteria diet in this setting .

The Center for Disease Control (CDC) has developed a list of foods that an HSCT patient should avoid as well as food safety guidelines. These guidelines should be the building blocks that individual institutions can utilize to develop their own version of a low-bacteria diet. These guidelines include the use of separate cutting boards for raw meats and vegetables, meticulous hand hygiene after handling of raw meats, and cooking meats to the appropriate internal temperature for that product.

Foods patients should avoid include:

In general, some version of a low-bacteria diet should be followed for 2–3 months post-autologous HSCT; allogeneic patients should continue until at least day + 100. In the end, it is up to the patient’s provider to determine when the dietary restrictions can be discontinued .

Probiotics are under study for the management of a variety of medical conditions. Their use is gaining popularity by both the medical community and general population. Probiotics can be found in over-the-counter capsules or in foods such as yogurt, kefir, and fortified milk. Strong evidence has been found for probiotic use for the treatment of infectious diarrhea and prevention/treatment of antibiotic-induced diarrhea. Theoretically, probiotic use in the HSCT population could be viewed as a way to treat antibiotic-induced or radiation-induced diarrhea ; however, this could promote infectious complications in this immunocompromised population. While probiotics are being utilized to treat medical conditions in the immune competent population, there have been no studies done to evaluate their efficacy in patients undergoing HSCT. Without those data, the safety of probiotics in HSCT recipients is unknown and use should be avoided, recognizing the risk of bacterial translocation though the GI tract wall potentially resulting in systemic infection .

Water safety is also a concern for these patients. HSCT recipients should avoid using well water as water testing is performed too infrequently. If patients choose to use tap water, they should heed public health advisories on water safety. Use of a water filtering system or home distiller may reduce the risk for waterborne pathogens found in tap water. The filter “should be capable of removing particles ≥ 1 µm in diameter or filter by reverse osmosis.” Bottled water should be used with caution and checked to be sure that reverse osmosis, distillation, or 1-µm particulate absolute filtration is used to remove Cryptosporidium (patients may need to check with the bottler to see whether this has been done). Also, patients should be aware that the water used to make ice, tea, coffee, etc. must be free of Cryptosporidium (especially important if patients are not residing in their own homes) .

GVHD is a T-cell-mediated immunologic reaction of engrafted lymphoid cells against the host tissue that may involve major organs, most commonly the skin, GI tract, and liver typically occurring within the first 100 days (acute GVHD). Clinical symptoms seen in patients with acute GVHD of GI tract may include abdominal pain /cramping, diarrhea, dysphagia, nausea, and vomiting . Chronic GVHD (commonly identified after the first 100 days) may be seen in some patients with symptoms of weight fluctuation, xerostomia, stomatitis, anorexia , reflux symptom, and diarrhea. All of these clinical findings can lead to malabsorption, bacterial translocation across the GI mucosa, dehydration, and weight loss in a patient population already at risk for these complications .

GVHD of the GI tract is especially challenging. Nutritional assessment and support of patients with GVHD of GI tract may be difficult due to inaccurate output measurement (large volume diarrhea , incontinence, or mix of stool/urine) as well as fluid retention which could mask weight loss.

Nutrition therapy can range from bowel rest and TPN to a diet that is low in GI stimulants/irritants (i.e., caffeine, lactose, acid, fat, and fiber) based on the severity of their symptoms. For patients with acute GVHD who present with large volume watery diarrhea and GI cramping, bowel rest and TPN are the initial steps of nutrition therapy. Once signs and symptoms have begun to improve (decreased abdominal cramping and decreased stool output, typically < 500 ml per day), patients may start a limited isotonic clear liquid diet. Once stools start to become formed, and the patient reports minimal cramping, one could start a diet that is low fat (20–40 gm/day), low fiber, and lactose restricted, with a gradual advancement to regular diet as tolerated. Regular monitoring for tolerance to advancement of diet is important. Increased diarrhea, emesis, or abdominal cramping should warrant a return to the previous dietary restrictions. Patients should remain on TPN until tolerating adequate calories and protein. EN in the form of tube feedings can be entertained at this time. The addition of new foods and diet advancement will vary by patient based on symptoms and tolerance. In patients with long-term chronic GVHD of GI tract, low-fat diet education and pancreatic enzymes may be beneficial.

Because HSCT patients are predisposed to malnutrition related to the disease process and conditioning regimen toxicities, they should receive ongoing nutrition assessment throughout the HSCT process, including nutritional and medical histories, anthropometry, chemistry review, and assessment of additional factors that may interfere with the patient taking adequate nutrition (pain control, activity level, etc.). This information will assist in determining the nutrient requirement for individual patients.