Researchers use postbiotic to ease acid reflux symptoms

A heat-killed probiotic bacterium has shown a benefit in cases of acid reflux, adding to the growing research linking probiotics and/or postbiotics in relation to this particular condition. 

The new research was published in the journal Nutrients. It was the work of a group of Japanese researchers associated with a medical school and cardiology clinic in Japan as well as employees of the Snowden Co., a Japanese manufacturer of pharmaceuticals, dietary supplements and beauty care products. The researchers acknowledge the support provided by Snowden, which included provision of the test material, though they claim Snowden did not fund the study. 

What's a 'postbiotic?'

“Postbiotic” is a term that is still applied to a number of different materials in the marketplace, even though a definition from the International Scientific Association of Prebiotics and Probiotics exists.  ISAPP defines a postbiotic as “a preparation of inanimate microorganisms and/or their components that confer a health benefit on the host.” 

The Japanese researchers were using a test material that aligns well with the ISAPP definition. They used a heat-killed probiotic strain identified as Lactobacillus johnsonii No. 1088 (LJ88), which is a proprietary Snowden Co. organism. The researchers noted that the heat-killed version is particularly attractive because of its longer shelf life. 

The researchers noted that both live and heat-killed LJ88 had previously elicited an anti-Helicobactor pylori activity both in vitro and in vivo. The presence of H. pylori in the stomach has been connected to gastric ulcers and other digestive issues, including acid reflux. 

An increasing amount of research in recent years has linked probiotics with beneficial effects on acid reflux. There is far less research linking postbiotics with these kinds of effects. 

Symptom severity judged with survey tool

To further elucidate the effects of heat-killed LJ88 (beyond a simple anti-H. pylori activity), the authors of the present study recruited 120 Japanese volunteers suffering from acid reflux symptoms, but who were otherwise healthy. The subjects were of both sexes and ranged in age from 21 to 63. The researchers used a tool called the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease (FSSG) to determine of the subjects’ symptoms were severe enough to warrant inclusion in the study. 

The FSSG is a survey tool that uses a scoring system to grade the answers to a series of questions such as “Do you get heartburn?” “Does your stomach get bloated?” and “Does your stomach ever feel heavy after meals?” There are 12 questions in all. The FSSG returns both a “total score,” which is more related to overall quality of life, and a “heartburn score,” which is related to the questions specifically mentioning heartburn.  

The subjects were divided into two groups who ingested the test material or a placebo for 6 weeks. They were instructed to maintain their standard diets and lifestyle habits in the interim. 

By the conclusion of the test the researchers noted that there was no statistically relevant change in the overall scores between the two groups. They noted that given the still unknown aspects of the gut-brain connection, there could be a high placebo effect in this kind of research. 

They also noted that they did not see the drop in the serum gastrin levels that they had expected with the use of the heat-killed LJ88. 

However, they noted that the heartburn score did improve significantly in the experiment group vs. placebo. 

Placebo effect possibly boosted by gut-brain link

Thus, they were confident in concluding that “the daily ingestion of heat-killed LJ88 (1 billion cells/day) for 6 weeks has beneficial effects on the temporal heartburn symptoms related to gastroesophageal reflux, and has no safety concerns.” 

However, it was clear that the researchers had hoped for more. The researchers noted that because of the brain-gut connection, the mental states of the subjects, which were not assessed in this study, could have had an outsized effect on the results. They suggested future studies could be conducted in which all the subjects had a common outside stressor, such as medical students during the season in which they take their academic tests, so that they all would be on more of a level playing field in terms of stress levels.