The Pure Probiotic Initiative: Probiotic Delivery Innovation

By Kelly C. Heim, Ph.D.

The clinical efficacy of a probiotic is contingent upon viability and function in the intestinal tract. To reach this destination, probiotics must prevail over multiple challenges in the upper digestive milieu. The first and most formidable adversity is the acidic environment of the stomach. As part of the body’s innate immune system, gastric acid serves as a first-line defense to destroy microorganisms. This rudimentary fact has raised a persistent question—can probiotics pass through the stomach intact?

Indeed, this question accounts for some skepticism in the medical community. In the realm of research, it has incited focused lines of investigation of gastric transit performance of various probiotics. Thus far, these studies have clearly asserted that probiotic organisms exhibit varying degrees of natural acid resistance, and the magnitude of this fortuitous attribute is dependent upon genus, species and strain.^‡1-3

Natural acid tolerance

Members of the genus Lactobacilli express a transporter that readily pumps acid protons across membranes. This maintains intracellular pH, lending intrinsic acid tolerance to most species of Lactobacilli. However, many Bifidobacteria lose viability at acidic pH values below 3.0.⁴ The extent of vulnerability varies considerably across species and strains. For example, Bifidobacterium lactis Bl-04 is exceptionally resilient, as more than 90% of cells will remain viable at pH 1.2 over a 2-hour period in simulated gastric fluid. However, under the same conditions, only 70-79% of Bifidobacterium longum Bl-05 survive.^‡5

Formulation with naturally hardy strains ensures that viable organisms reach the small and/or large intestine, where adhesion and colonization can ensue. This approach maximizes efficacy while circumventing the need for excipients. Through careful evaluation of data on specific strains, Pure Encapsulations selects only those that survive naturally at gastric pH over a physiologically relevant duration.^‡

Hypoallergenic intestinal delivery

Intestinal delivery technology remains an area of interest in probiotic product development. Historically, excipients required for enteric delivery have precluded integration into Pure Encapsulations’ product line. However, a recent innovation in acid-resistant capsule technology has provided a delivery option that meets the highest standards of purity. Featured in Probiotic 50B, this hypoallergenic, vegetarian capsule provides both protection from acid and targeted release. Remaining 85-99% intact at the low pH of the stomach, the capsule is an effective physical barrier against gastric acid. Upon entry into the more neutral intestinal fluid, dissolution occurs rapidly, releasing the live, active organisms (Figure 1).^‡

Formulation with naturally hardy strains ensures that viable organisms reach the small and/or large intestine, where adhesion and colonization can ensue. This approach maximizes efficacy while circumventing the need for excipients. Through careful evaluation of data on specific strains, Pure Encapsulations selects only those that survive naturally at gastric pH over a physiologically relevant duration.^‡

Figure 1. Percentage of ingredient released in simulated gastric fluids and intestinal fluids.6 After two hours in pH 1.2 simulated gastric fluids, less than 20% of capsule contents were released. After 60 minutes in pH 6.8 simulated intestinal fluids, more than 95% of capsule contents had dissolved.

Completing the journey

Once liberated in the intestine, the probiotic cells must fulfill two additional prerequisites to impart their health benefits. As with acid tolerance, their ability to withstand bile is strain-dependent. The five strains of Bifidobacteria and Lactobacilli in Probiotic 50B exhibit robust bile tolerance in vitro (Table 1). In addition, the strains effectively adhere to cultured intestinal mucosal cells. Epithelial adherence is critical because it precedes colonization, which allows beneficial shifts in intestinal ecology.^‡5

Table 1. Post-gastric performance  of strains in Probiotic 50B.  Data are derived from a compilation of supplier and published studies of simulated gastric and intestinal conditions at physiological pH.* *Survival in bile determined in vitro †Adherence determined in cell culture

A fundamental and decisive point of dietary supplement development is certainty that each ingredient can reach its site of action in the body. At Pure Encapsulations, innovations in probiotic product development continue to bring fully viable, functional organisms to every patient. This clinical reliability is a reflection of a long-standing commitment to excellence in sourcing, formulation, manufacturing and quality assurance.^‡

References

1. Tannock GW. A special fondness for Lactobacilli. Appl Environ Microbiol (2004) 70:3189-3194.
2. Jin LZ, Ho YW, Abdullah N, Jalaludin S. Acid and bile tolerance of Lactobacillus isolated from chicken intestine. Lett Appl Microbiol (1998) 27:183-185
3. Ronka E, Malinen E, Saarela M, et al. Probiotic and milk technological properties of Lactobacillus brevis. Int J Food Microbiol (2003) 83:63-74.
4. Corcoran BM, Stanton C, Fitzgerald GF, Ross RP.  Survival of probiotic lactobacilli in acidic environments is enhanced in the presence of metabolizable sugars.  Appl Environ Microbiol (2005) 71(6): 3060–3067.
5. Assay performed under a specific protocol that is available upon request.