What are probiotics exactly?

The World Health Organization (WHO) defines probiotics as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.” Probiotics generally do this by improving or restoring the gut flora and stopping undesirable bacteria from overgrowing in the gut. Gut flora refers to the microorganisms (i.e., invisible to the naked eye) that naturally live in your digestive tract and are key players in your health. Two important roles microorganisms play in the body are protection of the immune system and aiding metabolism. Therefore, consuming probiotics can help strengthen the ability of your gut flora to improve your overall health.

I often see similar products labeled with “live active cultures.” Why is ‎that? What are cultures?‎

The terms probiotics and cultures are often used interchangeably. Live food cultures are microorganisms often used to ferment foods and beverages. Probiotics are live microorganisms that have been shown to have a positive health effect. Live cultures are essential for creating many of the foods known to be rich in probiotics, for example, your favorite cheese. At the same time, cultures are used to create other fermented products like beer, which is not considered rich in probiotics.

What foods contain probiotics?‎

Unpasteurized sauerkraut, miso-containing foods, kimchi, kefir, sourdough bread, and tempeh are all examples of fermented foods belonging to a category that contain “live active cultures” that are naturally rich in probiotics or may have added probiotics. Similarly, yogurt also contains probiotics, either naturally or added. Probiotics can also come in capsule, tablet, powder, and liquid forms to be consumed as a dietary supplement. Knowing the many health benefits probiotics can offer, food scientists are also looking at new ways to add probiotics to everyday products like cereals and granola bars.

How do I know my food contains probiotics?‎

While probiotics must be identified on dietary supplements, they are not always listed on food labels, so it’s helpful to know what foods are naturally rich in probiotics (see above!). If you’re buying yogurt for its probiotic benefits, it must not be pasteurized. Make sure the ingredient list includes live and active cultures. According to the National Yogurt Association (NYA), yogurt must have at least 100 million cultures per gram in order to display a “Live and Active Cultures” seal on the label. You may notice the ingredient list also provides details on what specific probiotics are in the yogurt. Basic cultures or probiotics used to make yogurt include Lactobacillus bulgaricus and Streptococcus thermophilus, although other probiotics are often added to help maintain the balance of bacteria needed to support a healthy digestive tract and immune system.

What is the meaning behind those italicized probiotic names?‎

Probiotics, also known as “good bacteria” are identified by genus, species, and strain names. If genus were to refer to a population, the species would refer to one family, and the strain would refer to one person in that family. If you were to look at the ingredient list on a container of probiotic yogurt and see Lactobacillus rhamnosus LGG, you would know this probiotic belongs to the genus Lactobacillus, and the species rhamnosus. The specific strain (i.e., “person”) is LGG. Manufacturers also tend to abbreviate the genus name (e.g., L. for Lactobacillus)to save space. Studies have shown that physiological benefits are strain-specific. Therefore, food companies pay close attention to the probiotic strain when developing the probiotic-enriched products on grocery store shelves.

If probiotics are considered live and active, aren’t they perishable? If so, ‎should I be refrigerating anything containing probiotics?‎

You should always consult the date labeling marked on packaged food products and dietary supplements. When it comes to refrigeration, while many probiotic supplements should be refrigerated to ensure their potency, other probiotics are less sensitive to temperature, light and moisture and are considered shelf-stable. In the case of dietary supplements, it is best to consult the manufacturer’s instructions.

What specific health benefits do probiotics offer?‎

Just as various nutrients support your overall health in different ways, certain groups of probiotics have proven to be more effective than others for treating specific conditions. For example, B. animalis subsp.lactis, B. longum, and S. cerevisiae may improve constipation, whereas Lactobacillus acidophilus and Lactobacillus bulgaricus may improve lactose digestion for those with digestive discomfort related to lactose digestion. It’s important to seek out credible sources for information on probiotics and specific health conditions. At the same time, note that each person has a unique gut flora, diet, and medication usage which may impact the efficacy of probiotics. One of the best things you can do is choose a probiotic from a reputable company.

How many probiotics should I be consuming?‎

There is no Acceptable Daily Intake (ADI) for probiotics, but probiotics must be consumed in sufficient amounts in order to experience their intended health benefits. Currently, probiotics must be listed on supplement labels by weight in milligrams (mg), which denotes the quantity of probiotics present at the time of manufacture. While this measure reveals some information about the amount of probiotic, it may not always accurately express the efficacy of the probiotic. A clearer indicator to look for is colony-forming units (CFU), which FDA allows companies to include on labels in addition to weight in milligrams. CFUs indicate the number of live and active cultures found in each serving of probiotic, so it is a significant gauge of how potent and effective the probiotic will be when consumed. Although higher CFU levels have been found to produce better results, it is important to remember that the effects of different probiotics often vary from person to person. Therefore, people may find probiotics to be effective at different CFU doses.