Dose-response effect of Bifidobacterium lactis HN019 on whole gut transit time and functional gastrointestinal symptoms in adults

Introduction Functional gastrointestinal symptoms are nonspecific conditions with no identifiable structural or biochemical cause [1] that often present concomitantly [2]. The burden of functional gastrointestinal symptoms is enormous as 42–69% of the population report at least one of these disorders [3,4]. Treatment is complicated by the non-specific presentation of symptoms and by the fact that 75% of people do not seek medical care when symptoms arise [5]. Therefore, management of functional gastrointestinal symptoms is generally self-prescribed and directed at treating individual symptoms. Despite acceptable short-term symptom amelioration with over-thecounter and homeopathic remedies in many cases, no known treatment for functional gastrointestinal symptoms is known to be safe and effective over the long term. Functional gastrointestinal symptoms are often associated with disturbed intestinal transit. Whole gut transit time (WGTT) significantly influences enterohepatic bile acid and steroid hormone circulation as well as colonic pH and short-chain fatty acid concentrations. Thus, it has been postulated that functional gastrointestinal symptoms may be Correspondence: Larry E. Miller, PhD, Sprim Advanced Life Sciences, 235 Pine Street, Suite 1175, San Francisco, CA 94104, Sprim, USA. Tel: . Fax: . E-mail: (Received 19 December 2010; accepted 25 April 2011) ISSN print/ISSN online  2011 Informa Healthcare DOI: 10.3109/.2011.584895 Scand J Gastroenterol Downloaded from by Danisco AS on 06/22/11 For personal use only. associated with an increased risk of gallstones, and possibly bowel and breast cancer, when presenting concomitantly with prolonged WGTT [6]. There is a clear need for treatments for functional gastrointestinal symptoms and intestinal transit disturbances that are safe, effective, and sustainable. There is a growing consumer interest in functional foods that can either promote the state of well being and/or alleviate symptoms of certain medical conditions. Probiotics may offer a promising alternative that can be offered in a food or dietary supplement format that is appealing to consumer preferences. Probiotics have been extensively studied in the field of gastroenterology and show potential for improving gastrointestinal symptoms and reducing WGTT [7–11]. However, the benefit of probiotic supplementation is believed to be strain specific and, therefore, clinical trials are required to confirm the safety and efficacy of individual strains. Bifidobacterium lactis HN019 is a probiotic strain for which many health benefits have been established, primarily related to immune enhancement [12]. B. lactis HN019 has also been shown to confer beneficial changes to the intestinal microflora [13] although no studies have examined the effects of B. lactis HN019 on functional gastrointestinal symptoms or WGTT. This study was designed to determine in a triple-blind, randomized, placebocontrolled trial if dietary supplementation of B. lactis HN019 can shorten WGTT and reduce the frequency of functional gastrointestinal symptoms in adults. Material and methods This single-center, triple-blind, randomized, placebocontrolled, dose-ranging study was conducted at Accurate Clinical Research (Houston, TX, USA). All research procedures performed in this trial were in strict accordance with a pre-defined protocol that was approved by all researchers. IntegReview Ethical Review Board (Austin, TX, USA) approved the study protocol on 11 August 2009 and participants provided informed consent before participation. This study is registered under ClinicalT number NCT. Trial design This was a single center, age- (25–50 years and 51–65 years) and gender-stratified, triple-blind, placebo-controlled, parallel-group, dose-ranging study with a 1:1:1 allocation ratio among three study groups. Participants Eligible subjects included males and fe