When shopping for probiotics today you’ll see two mains types of probiotics available today:

1. Shelf Stable

Shelf stable probiotics are encapsulated typically through either freeze-drying or spray-drying technique . This involves a vacuuming process that sucks all the liquid and humidity out of the environment of the bacteria allowing for them to remain alive at room temperature. These techniques tend to have a longer shelf life compared to the “live” probiotics.

Some probiotics use double encapsulation methods in order to keep excess heat and moisture away from the bacteria. Many of these utilize this second encapsulation to supply the bacteria with fermentable fiber to provide them with nutrients. This has been shown in some research to increase the bacteria’s absorption into the intestine. 

2. Refrigerated

Refrigerated probiotics are live probiotics that are placed directly into capsules. These probiotics must be refrigerated to ensure the bacteria does not die due to excess heat, stress or humidity. The cold environment also helps to slow the bacteria down, so they do not starve from a lack of nutrients. Many refrigerated probiotics will be packaged with blister packs in order to keep them cold in the shipping process. Probiotics that aren’t freeze-dried or spray dried have a higher likelihood of being exposed to excess heat and/or humidity during the shipping process.

It’s worth noting that not all bacteria need to be freeze-dried or refrigerated in order to be packaged up. Certain strains of bacteria are extremely resistant, basically meaning they’re hard to kill. In this context, these bacteria can exist on a shelf for decently periods of time without issue and still be alive once consumed. 

The Consensus: 

Generally, I would recommend shelf-stable probiotics because they are believed to have a longer shelf life and are less susceptible to being exposed to “extreme” weather conditions.

Whether or not the probiotic makes its way into the large intestine depends on what the probiotic is encapsulated in. There are a number of encapsulations used for probiotics, most typically indigestible materials like cellulose or fermentable fibers. 

Cellulose

For most supplements I’d recommend avoiding cellulose, as humans cannot break down cellulose since we don’t produce the enzyme cellulase, which is necessary to do so. Cellulose in our body is not broken down unless the bacteria in our colon “feed” on it through fermentation.  This is beneficial in the case of probiotics because as you know you do not want the probiotic to be released in the stomach or small intestine or it can cause bacterial overgrowth in these locations. For this reason, probiotics encapsulated in cellulose make a very viable option for ensuring the bacteria make their way into the colon.

Fermentable Fibers

Fermentable fibers are again something I generally recommend avoiding when it comes to optimal health. This is because fermentable fibers, like cellulose, are indigestible by the digestive proteins in our stomach or small intestines. Unlike cellulose, fermentable fibers are easily fermented by the bacteria in our colon. This has a two-fold benefit, first it can help to feed the bacteria within the capsule, increasing their likelihood of surviving while in the capsule. Second, the fermentable fiber can help to facilitate these probiotics to make more permanent changes to your gut microbiome. A lot of the research on probiotics seems to show that they are only benefiting you, while you are taking them, after you stop taking them a lot of the time the microbiome seems to go back to its previous state.  The addition of fermentable fibers with the bacteria may be able to help make more permanent changes in your gut microbiome that last beyond the dose of probiotics. 

Short & Medium Chain Triglycerides

Short and medium chain fatty acids (triglycerides), also known as SCT's & MCT's respectively, have been shown to have a number of benefits in fighting "bad bacteria", improving the gut microbiome and the body's ability to use fat as fuel. MCT's in particular have been shown to have an anti-microbial effect, reducing the "bad bacteria" present in the colon. This is very beneficial when combined with probiotics as it increases the chances of making more long-term changes in your gut microbiome.