Fermentation is a type of food processing or food preparation to make foods such as yogurt, kimchi (pictured), sauerkraut, and tempeh which contain live cultures or probiotics. Probiotics are the good bacteria found in the gut and help your body digest food. Learn more about probiotics from Harvard Medical School and the Cancer Dietitian.
Should you eat more fermented foods? A recent study shows that the answer may be yes. Fermented foods have long been a part of many cultures’ diets as fermentation is used to preserve food without refrigeration. Fermented foods have a plethora of bacteria that may be beneficial to increase the amount of good gut bacteria while lowering the amount of pathogenic bacteria. In particular, a study titled “Fermented Foods: Are They Tasty Medicines for Helicobacter pylori Associated Peptic Ulcer and Gastric Cancer?” looks at using fermented foods in prevention of Helicobactor pylori (H. Pylori) infection, one of the causes of gastric cancer.
The study examines the benefits of adding probiotics to the antibiotic treatment of H. pylori infection. Including probiotics can help prevent side effects from the antibiotics. The combination can also prevent the entrance of harmful bacteria into the body’s collection good bacteria. The researchers explain that previous studies have proven the benefits of natural probiotics contained within certain fermented foods such as kefir, yogurt, and sauerkraut. These foods contain beneficial bacteria, particularly Lactobacillus, that have anti H. pylori properties and reduce the side effects of antibiotic treatment of H. Pylori.
There is still some confusion of how consumption of fermented foods in certain cultures correlates with both high and low prevalence of gastric cancer in different regions. It appears there may be other factors at work such as genetics and the types of foods being fermented. Additionally, fermented food are usually not eaten alone but paired with other foods that may affect the risk of gastric cancer. Inclusion of high amounts of sodium into some cultures’ fermented foods, such as in Japanese and Korean foods, may be a factor in the high percentage of gastric cancer within these specific populations.
There is still much to be studied concerning the effects of fermented foods on good and bad gut bacteria, but evidence suggests that adding low-sodium fermented foods yogurt, kefir, and sauerkraut will be beneficial in creating healthy gut bacteria which could reduce the risk of bad gut bacteria linked to gastric cancer.
Author: Emily Vaughan, Senior Student in the Lipscomb University Didactic Program in Dietetics
A Note from PearlPoint Cancer Support:
Are fermented foods safe for everyone, even someone during cancer treatment? For most healthy people, low- sodium fermented foods may be part of a healthy menu each week. If you have food allergies or digestive issues, talk with your healthcare provider or registered dietitian before adding fermented foods to your lifestyle. For people who are immunosuppressed or are not well, especially during cancer treatment, some fermented foods may not be suggested. One example is Tempe (tempeh) products. Tempe (tempeh) is a fermented food made by the controlled fermentation of cooked soy beans with a Rhizopus mold. 
 Nair, Mydhily R. B. et al. “Fermented Foods: Are They Tasty Medicines forHelicobacter PyloriAssociated Peptic Ulcer and Gastric Cancer?“Frontiers in Microbiology7 (2016): 1148.PMC. Web. 3 Jan. 2017.
 Lampe, Johanna W. “Fermented Foods: Intake and Implications for Cancer Risk.” AICR’s 2013 Annual Research Conference on Food, Nutrition, Physical Activity and Cancer. Hyatt Regency Bethesda, Bethesda. 7-8 Nov. 2013. Presentation.