The Problem with “Promiscuous” Probiotic Blends

What makes a probiotic blend “promiscuous?” This is when a manufacturer throws in a lot of strains of organisms together without much thought or effort into their combined actions in the body. To make a combination more marketable- companies often think “more is better.” Unfortunately, “more” can be at best useless, and occasionally it can be harmful.

One example is the introduction of strains of yeast to a probiotic blend. Given the data to support the use of probiotic bacteria, why would anyone need to ingest more yeast? Many people are already sensitized to yeast, and may feel worse when taking these supplements. Some compromised patients risk acquiring fungemia from exposure to high dose live yeasts. Because yeasts are more difficult to eradicate than bacteria, this can become a dangerous situation for a sensitive person. One manufacturer touts the addition of 7 additional strains of yeast as a competitive edge, yet this includes strains that the scientific community is not even familiar with yet.

Another example is one company’s claim of “synergy” between its multitude of included strains. Synergy is defined as cooperative action and it is not a preferred state between microbial organisms. The truth is, no one really knows what happens when you put together a number of largely unstudied organisms into a blend. The most common result is mutual antagonism.

A better approach would be to ask, “What is the purpose of each strain included in this combination?” Species of bacteria within bifidobacteria and lactobacilli (genus) are well researched in their many beneficial effects on the large and small intestines, respectively. In addition, their safety is well established.

As a final reminder: if there are multiple strains in a product, there should be a clear purpose for each strain’s inclusion, and an expiration date needs to be listed for each.