With a growing number of probiotic products on the market today, I’m not surprised that more people are asking, “How can I make sure I choose the best probiotic supplement?”

I tell everyone who approaches me about this that the best way to support digestive health is first to add more probiotic foods, such as yogurt, sauerkraut, and kefir to your daily diet. But if you can’t eat those foods every day—or don’t care for their taste—then your best option is to take a probiotic supplement.

In my 20-plus years of research and writing about probiotics and digestive health, I’ve found that there are a few basic criteria on which to evaluate probiotic supplements when you’re deciding which one will work best for you. They are—

The specific probiotic strains included

The product’s packaging and delivery system

Product expiration dates

Money-back guarantee

The Specific Probiotic Strains Included

Many retailers would have you believe that the best probiotic supplement is the one with the most bacteria it (typically measured in colony-forming units, or CFUs).

However, the truth is that science doesn’t know yet if more bacteria are actually better for you. In fact, we still don’t even know for sure how many different strains of probiotic bacteria are in the gut to begin with. So sales pitches that say more is better are just that—sales pitches.

See a list of all articles about Gut Bacteria in the Gut Bacteria and Probiotics Index

My interpretation of the research to date has convinced me that it’s not the total number of bacteria in a product that is most important; it’s the number of different strains of bacteria it includes.

Because the different strains of probiotic bacteria have slightly different functions and are concentrated in various places along the digestive tract, probiotic supplements that contain multiple strains tend to be more effective overall than products containing an extremely high concentration of just one or two strains. This is because many strains work synergistically to influence our health. The whole literally is greater than the sum of its parts.

In my opinion, the best probiotic supplements will include at least these three most important strains:

L. acidophilus—This is the most important strain of the Lactobacillus species and, it readily colonizes on the walls of the small intestine. It supports nutrient absorption and helps with the digestion of dairy foods.

B. longum—Like L. acidophilus, B. Longum is one of the most common bacteria found in the digestive tracts of adults, and it helps maintain the integrity of the gut wall. It is particularly active as a scavenger of toxins.

B. bifidum—This strain, found in both the small and large intestine, is critical for the healthy digestion of dairy products. This is especially important as you grow older and your natural ability to digest dairy declines. B. bifidum also is important for its ability to break down complex carbohydrates, fat, and protein into small components that the body can use more efficiently.

Secondarily, I like:

L. rhamnosus—Known as the premier "travel probiotic," this strain can help prevent occasional traveler's diarrhea.

L. fermentum—This Lactobacillus strain helps neutralize some of the byproducts of digestion and promote a healthy level of gut bacteria.

Beyond these, the best probiotic supplement for you depends on your specific health concerns. The optimal choice for women, for example, is likely to be different than for men. Learn more about the different probiotic species and strains and their benefits.Product Delivery System and PackagingUnderstanding the different ways that manufacturers package and deliver probiotic supplements is perhaps the most important factor in choosing one, and that’s because it won’t matter which product you select if its delivery system doesn’t work.When I say “delivery system,” I mean the form in which the product is created and how that form enables the bacteria both to remain alive and healthy while on store shelves, and to reach the areas in your gut where they’ll be most effective.A probiotic supplement full of dead bacteria—or bacteria that die in a sea of stomach acid—is a waste of money.There have been a lot of advances in delivery systems in recent years, and it’s possible that by the time you read this, there will be something available that’s even better than the controlled-release tablet (or caplet) that is my current favorite. “Beadlet” technology is still viable, and capsule formulation has come a long way since the days when those pills were instantly obliterated by stomach acid.The best probiotic supplements will use delivery systems that ensure a significantly high percentage of bacteria will reach your intestines alive. Because this has become a notable selling point, look for details on the product’s packaging or marketing materials. A company that is willing to explain how their product works most likely has a product that will, indeed, work.Also look closely at how the product is packaged. Because probiotic bacteria are living organisms, their health can be affected by their environment.For example, you may remember a time when you had to refrigerate probiotic supplements. New delivery systems have mostly done away with that requirement, but you still need to protect the bacteria from too much exposure to light, heat, and moisture. Look for packaging that ensures these elements will have minimal impact. Thick, opaque bottles with desiccant pouches are most preferred, but there are some new styles of blister packs that also work well.

Expiration Dates

The supplement industry doesn’t require that products have expiration dates, so this bit of information can be telling when it comes to product quality.A stated expiration date on a probiotic supplement is the manufacturer’s promise that the bacteria in the product will remain active and potent—at the levels specified on the label—until that date. Usually the expiration date is based on formulation and stability testing data, which means a company is paying attention to those matters.The best probiotic supplements will display clearly labeled expiration dates. If you don’t see an expiration date on a product label, it should raise questions. Without expiration information, it’s impossible to know how long the bacteria in the supplement are expected to last. It could be a year, or it could be a week. Or the bacteria may already be dead—you have no way of knowing. Recently I’ve also noticed a trend of retailers forgoing expiration dates in lieu of stamps that guarantee potency on the date of manufacture.This is useless in my opinion, because all products should live up to their label claim when they leave the manufacturing facility. As a buyer, I want to know that the product will still be potent 3–4 months later (particularly if I’m buying a few bottles at a time).Don’t risk wasting your money on a product that may provide minimal or no benefit. Look for an expiration date. Along with the delivery system, it’s the best way to ensure that you’re getting the best probiotic supplement available. Money-Back GuaranteeFinally, always insist on this for any supplement you take, including your probiotic. Companies that truly believe in their products will stand by them.

Dr David Williams

So to summarise form my findings the best pro biotic I have found is