- Contains at least 10 different species of bacteria. The most well researched strains of beneficial bacteria are species within the genera Bifidobacteria, Lactobacteria, Propionobacteria, physiological strains of E. coli, Peptostroptococci, and Enterococci. The probiotic yeast Saccharomyces boulardii is another well-studied species that is frequently put into probiotic formulas, but it is a yeast and not a bacteria (don't get uptight about it being a yeast - the "Candida overgrowth" fad is not actually a problem, so there's very little risk of S. boulardii causing problems either).
- Contains at least 10 billion CFUs per pill.
- Make sure the label says something like, "potency guaranteed at time of consumption" or "potency guaranteed until expiration date". It should NOT say, "potency guaranteed at time of manufacture" because that means that after the pills leave the factory, there is no guarantee that any of the bacteria will remain alive by the time that you consume them. If there is no statement on the label about potency at all, then that is certainly not a high-quality product.
- The probiotics are encapsulated in such a way to protect them from stomach acid. Some companies created special enteric coating or fancy encapsulation techniques, which is great. But to make sure you're getting the most out of your probiotic it's best to take them at the end of the day when stomach acid is lowest, like right before bed, or with plenty of fiber and prebiotic starches, either with dinner or an evening snack. Taking probiotics with fermentable prebiotic fibers is what I try to do, because that ensures that when they reach the intestines those beneficial bacteria have the food that they need to survive in their new habitat.
- They must be either freeze-dried encapsulated and therefore shelf-stable (like Culturelle and BioKult) or refrigerated throughout the entire chain of transit and in the store. A probiotic has to be stored in one of these two ways or else potency is significantly reduced in transit and storage, and by the time it gets to you it may not be probiotic at all.
- Try to choose probiotics with the least amount of added fillers (like lactose). But some probiotics come with prebiotic fibers added in, and we call these synbiotics. These prebiotics often include inulin from roots like dandelion and burdock, or vegetable/fruit fibers and starches. Synbiotics are wonderful and you should preferentially buy these as long as you can tolerate FODMAPs alright. Synbiotics provide a little dose of the probiotics' preferred food source, complex carbohydrates that serve as prebiotic fiber to ensure that they have the food that they need to become established residents of your intestinal ecosystem.
- If probiotics with Lactobacillus species in them make your digestive symptoms worse, consider taking a soil bacteria based probiotic, like MegaSpore.
- Kids' formulas have fewer CFUs per capsule, and some aimed at infants or toddlers contain bacterial species known to be found specifically in the infant/toddler gut. However, the adult gut is so heterogeneous that we do not yet know enough formulate "men's" or "women's" or "senior" formulas. So it is perfectly fine for females to take "men's" formulas or males to take "women's" formulas. The differences between them are mostly marketing.
- Probiotic pills are great for acute situations when we need high doses of bacteria or when it is difficult to tolerate food-based probiotic species. But the BEST way to get in enough probiotic bacteria everyday is to eat live fermented foods like sauerkraut, kimchi, real yogurt, kefir, kombucha, etc. Eating fermented foods is the most traditional, sustainable, and cheapest way to make sure you ingest a diversity of probiotic species (most probiotic foods have greater species diversity than pills) on a regular basis.
- Eat dirty vegetables. If you have access to high-quality organic fruits and vegetables, don't wash them! Eat them with a little dirt still caked on them, if you know the soils from which they came are healthy. In the summer I either grow my own produce or I buy it from the farmers market, and I try to leave as much dirt on my carrots and kale as possible (without feeling like I'm chewing sand). Dirt is full of trillions of beneficial microorganisms that our species has coevolved with. It is only since our culture has become "over-civilized" and afraid of germs that our internal ecological diversity has waned, taking a huge toll on our health. The human animal needs to be constantly exposed to healthy soil in order to develop a healthy microbiome. Make sure your kids play in the mud, and eat a little too! A little dirt don't hurt!
- Have you kissed your dog today? No, really. You should. Having pets and being around farm animals is one of the most beneficial things you can do for your microbiome. Many studies have shown that kids who grow up on farms have much lower risks of developing diseases of modernity like asthma, allergies, and autoimmunity. Having pets is also beneficial, though to a lesser degree. Ensuring you have enough exposure to a wide range of non-human animals builds your immune system by swapping microbes with our animal friends.
Example of a GOOD brand - Garden of Life's Dr. Formulated line:
Example of a BAD brand - Nature's Bounty Controlled Delivery Probiotic CD: