Influence of a Delivery System on the Efficacy of a Probiotic Intervention

Overview

In the proposed work we will evaluate the efficacy of a probiotic bacterium (Bifidobacterium animalis subsp. lactis BB12) delivered in a yogurt smoothie (organism to be added before or after fermentation) or as a supplement (tablet) by assessing 1) bowel habits (transit time); 2) the ecology of the bacterial community in the GIT; and 3) immune status of healthy human volunteers. In addition to providing information about the relative efficacy of the delivery vehicles on probiotic function it will provide novel information about the influence of the yogurt smoothie alone (control) on all the parameters measured.

Probiotics (health-promoting bacteria) are often considered "functional ingredients" that act independently of the matrix used to deliver them to the human host. This thinking ignores the impact the delivery matrix (food or dietary supplement) may have on both the physiology of the probiotic organism and on the human host and is likely not true. Historically the most common "probiotic foods" have been fermented dairy products, particularly yogurts. Since yogurts are commonly understood to contain live "good" bacteria they are well accepted by consumers. However, increasingly over the last decade, probiotics are being added to non-dairy-based foods (juice, chocolate, cookies, etc) or consumed as supplements (tablets/capsules). While this expands the options for people to obtain probiotic organism, it is not clear whether probiotics delivered in these products are as efficacious as when delivered in a dairy food. In fact, the buffering capacity and nutrient composition of milk products may directly influence efficacy of the probiotic by increasing survival during passage through the gastrointestinal tract (GIT) and by modifying the physiology of the probiotic organism. In addition, fermentation products produced by the probiotic during manufacture of yogurt may also have an influence on the efficacy of probiotic bacteria. Our hypotheses are: 1. The vehicle used to deliver probiotic bacteria into the body influences the performance of the probiotic in vivo. Specifically, consumption of yogurt-based smoothie containing probiotic bacteria will result in greater decrease in fecal transit time, and have a greater effect on the composition of the fecal microbiota and on markers of immune status than the same probiotic bacteria delivered at the same level in the form of a dietary supplement (tablet). 2. Timing of the addition of probiotic organism to the yogurt smoothie (pre or post fermentation) will not change the efficacy of the probiotic with respect to the outcomes being assessed.