There’s been a lot of buzz around probiotics lately, but are the claims legitimate? A probiotic is simply a beneficial microorganism that may influence your health. They’re found naturally in fermented foods, sold in supplements and added to functional foods and beverages.
Insights into the $2 billion industry cite potential benefits for both digestive and skin conditions as top reasons for probiotics’ exploding popularity. Whether you get any benefit from these products may come down to the genus, species and strain.
What are probiotic strains?
When you look at the label on a probiotic supplement, you’ll see a list of the microorganisms it contains. Each microorganism is identified by a two-part name, such as Lactobacillus acidophilus, where Lactobacillus is the genus and acidophilus is the species.
Some species names may be followed by a number, which indicates the supplement manufacturer used a specific strain. Different strains have been associated with different health benefits in scientific studies, some of which may be unique to a particular strain.
What are the functional properties of specific species and strains?
The benefits associated with probiotics come not from the microorganisms themselves but the byproducts they excrete. For example, Bifidobacterium produce mainly short-chain fatty acids, while Lactobacilli produce lactic acid. Each byproduct affects your body – and your health – in different ways.
Because the gut microbiome is so complex, science has only identified a handful of strains within the known genera and species of probiotic microorganisms. Several strains have researched-backed benefits for specific health conditions.
For better bowel habits:
These strains have been shown to reduce gas in IBS patients, clear up occasional constipation and promote regularity†:
- Bifidobacterium lactis DN0173 010
- Bifidobacterium lactis HN019
- Escherichia coli Nissle 1917
- Lactobacillus casei Shirota
- Lactobacillus plantarum DSM 9843
For reducing digestive distress:
The beneficial yeast known as Saccharomyces boulardi is actually a strain of Saccharomyces cerevisiae and may reduce symptoms associated with†:
For improved mood:
Lactobacillus rhamnosus JB-1 supplementation may increase levels of GABA, a calming neurotransmitter than can help alleviate stress and anxiety.†
To support healthy cholesterol:
Some evidence suggests these strains may absorb cholesterol in the gut to support healthy cholesterol levels†:
- Lactobacillus acidophilus ATCC 314
- Lactobacillus reuteri NCIMB 11951
- Lactobacillus reuteri NCIMB 701089
Choosing a quality probiotic: What works?
Despite the popularity of probiotics, supplements are still unregulated. That means you can’t always know if the strains on the label are actually in the bottle. So, how can you choose the right probiotic supplement to address your health concerns?
The best probiotics will have:
- A guaranteed number of live CFUs (colony-forming units) at the end of shelf life
- Allergy-friendly ingredients
- Formulas without fillers or binders
You can find both refrigerated and shelf-stable probiotics that meet these criteria. If you have a specific condition for which probiotics may be beneficial, look for formulas that contain strain numbers associated with benefits for that condition.
Do any probiotic strains have side effects?
A word of caution: Some people do experience side effects from probiotics regardless of strain. Symptoms may include:
- Digestive discomfort
- Increased histamine levels
- Allergic reactions to supplement ingredients
Probiotics aren’t recommended for people with cancer or compromised immune systems, or for anyone requiring long periods of hospitalization. Supplementing with probiotics may cause infections in these cases.
Are multi-strain probiotics better?
Microbial diversity in the gut is often associated with positive health outcomes, so taking a multi-strain probiotic in which the various strains have similar or complementary benefits may be better than sticking to a single strain. Scientists don’t fully understand how various strains work together, but there may be synergistic effects that result in greater benefits than a single strain can deliver on its own.
However, because individual strains have been shown to confer unique benefits, there may be situations in which a single-strain supplement would be the right choice. Just be careful about mixing multiple single-strain supplements; this could lead to unwanted side effects.
Whether you decide on a single- or multi-strain probiotic, make sure there’s science to back up the manufacturer’s claims regarding the benefits. With all of the possible effects probiotics can have – positive and negative – it’s best to do some research and talk to your doctor before putting yourself on a supplement.
Supplementation appears to work best for addressing specific conditions, so you may not get any benefit from taking probiotics if you’re generally healthy. If you do decide to take one or more probiotic strains, ask your doctor about any possible interactions with your other medications and supplements. Stop taking the supplement if you experience any digestive discomfort or allergic reactions.
†These statements have not been approved by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent disease.