How do I Choose the Best Probiotic?

Probiotics are superb for promoting health – and when deciding to incorporate them into your health and self-care regimen, you may be a bit overwhelmed when you discover that unlike any other dietary supplement category, there are numerous types of specific probiotics with different scientifically shown functions in the body.

But that’s what makes probiotics so exciting – it truly is a whole new world, and a world of good at that. If you’re researching online or simply looking at probiotic products, you will see a host of multi-syllabic Latin names often (but not always) followed by what looks like a secret code of capital letters and/or numbers.

You may also hear about probiotic “strains” which may be quite confusing. To understand what you are looking at, let’s use “Lactobacillus paracasei CNCM I-1572” as an example. You see “Lactobacillus” a lot. You also see “Bifidobacterium.” Each designates the genus, underneath each genus is the species. In this case, paracasei. Each species has a family of strains, and in keeping with our case, the strain here is CNCM I-5272. More precisely, describes one source, “probiotic strains are genetic subtypes of species. Each probiotic strain has a different effect in the body.”

You will often encounter products that do not specify the exact strain, just the genus and species, and often that’s OK. But when you get into seeking which probiotic is best for you, you may want to learn more about each species family member (strain) and how it has been shown via clinical research to affect a system such as digestion, or condition, such as cholesterol profile.

Often, the most challenging part of shopping for probiotics is selecting the most effective strain or combined strains in a product for what you hope them to accomplish. Keep in mind, however, unlike what some brand marketers may want you to believe: there’s no such thing as a “one-size-fits-all” strain of probiotic.



Species of Lactobacillus are the foundation of good gut health. These friendly bacteria make themselves at home primarily in the small intestine.

Lactobacillus plantarum
When you hear that fermented foods are outstanding sources of probiotic bacteria, it’s primarily because sauerkraut, kimchi and other cultured foods are abundant in the species Lactobacillus plantarum. It’s known for its extraordinary capability of surviving stomach acids. Because L. plantarum helps to reduce gut permeability, it’s suitable to consume for protecting against uncomfortable digestive symptoms like gas and bloating, and discomfort caused by leaky gut. L. plantarum helps keep the body healthy and supports the immune system in fighting against harmful pathogens through helping the body absorb essential vitamins and minerals that may otherwise be excreted. As a result, it’s one of the best “general” probiotic strains available, and one that many people benefit from soon after starting to take it.

Strain specific: L. plantarum 299V has been shown to reduce pain, bloating and improve constipation of irritable bowel syndrome (IBS). In one study of 40 individuals with IBS, researchers found that all those in the probiotic group reported resolution of abdominal pain in the four-month study.

Lactobacillus gasseri
This species is found primarily in human breast milk, so it would make sense that it is a powerful protector in the body. Several strains have also been investigated for weight management benefits.

Strain specific: Lactobacillus gasseri BNR17 has been shown to possess typical characteristics of probiotics including acid resistance, bile tolerance, and antimicrobial activity in lab tests. The ensuing animal tests uncovered the fat oxidation mechanism of L. gasseri BNR17, and the clinical trials conducted in two medical centers, including Seoul National University Hospital, verified the human body fat reduction effect.

In one 12-week study 57 participants were given either a placebo or BNR17 and had measurements of body fat, weight, among others at four week intervals. At the 12th week, a slight reduction in body weight was noted in the BNR17 group and decreases in waist and hip circumferences were more pronounced in the BNR17 group than those in the placebo group.

Lactobacillus rhamnosus GG
If you are prone to bouts of diarrhea from traveling, or antibiotic therapy, the species L. rhamnosus GG may be one of your best probiotic therapy options; as it fights pathogens in the gut and assists in the digestion of lactose. L. rhamnosus GG was first identified only in 1983 and is considered, according to one source, to be “one of the most studied probiotics, with research showing that it could alleviate rotavirus diarrhea in children, prevent atopic dermatitis, protect against urinary tract infections, and improve symptoms of irritable bowel syndrome.”

Strain specific: Lactobacillus rhamnosus GG (ATCC 53103) can be useful during winter when we’re stuck inside in proximity to others and don’t get much fresh air. In the case of upper respiratory health, one study showed this strain exerted inhibitory activity against a variety of bacterial species, including streptococci.

Lactobacillus brevis
L. brevis helps to enhance immune function and can boost cellular immunity, which may help to fight against free-radicals and other health disruptors. It’s also been shown to increase production of BDNF (an important hormone for brain health).

Strain specific: One study showed that Lactobacillus brevis OG1 produced bacteriocin, which itself exhibited inhibition of a wide spectrum of pathogenic and food spoilage microorganisms. Specifically, L. brevis OG1-produced bacteriocin inhibited E. coli NCTD 10418 and Enterococcus faecalis.

Lactobacillus acidophilus
L. acidophilus is the most recognized species as it has been sold for decades; it primarily was found in health food store refrigerators. This species produces lactic acid by breaking down carbohydrates, notably lactose found in milk and dairy. L. acidophilus is an ideal strain for those who have irritable bowel disorders and it is known to help fight pathogenic bacteria and help lessen symptoms of bacterial vaginosis. L. acidophilus is one of the most effective probiotics that support healthy digestion, and the species is known to help synthesize Vitamin K.

Strain specific: L. acidophilus DDS-1 has been shown in healthy adults (aged 18 to 75 who complained of lactose intolerance symptoms, to improve abdominal symptom scores (cramping, diarrhea and others) compared to placebo during an acute lactose challenge.

Lactobacillus paracasei
L. paracasei is a powerful immune-enhancing probiotic species. Some research has shown it does so by enhancing natural killer (NK) cell activity, lymphocyte proliferation and antibody production.

Strain Specific: L. paracasei CNCM I-1572 — also known as LP-DG™ — is the subject of more than 20 human clinical studies where it has been shown promote healthy immune and digestive functions. One trial of 40 individuals with IBS who took L. paracasei LP-DG™ exhibited modulated gut microbiota structure/function and reduced immune activation (IBS is an autoimmune disorder).

Lactobacillus reuteri
This species tends to favor colonization in the intestine as well as the oral cavity. One study showed that it decreased the oral bacteria that cause tooth decay. It’s also thought to help the digestive system. It is resistant to acid and bile, and strains in this species have been shown to promote oral and cardiovascular health, especially in women.

Strain specific: L. reuteri NCIMB 30242 or LRC™ can promote cardiovascular wellness by helping to manage healthy cholesterol levels. One trial of 127 individuals who consumed either L. reuteri NCIMB 30242 or placebo for nine weeks showed reduced LDL-cholesterol by 11.6%, total cholesterol by 9.1%, and non-HDL-cholesterol by 11.3%.


Bifidobacteria colonizes primarily in the large intestine, also known as the colon. Bifidobacteria are known to help produce thiamine, riboflavin, Vitamin B-6, and Vitamin K. and some research has suggested that bacteria in this genus may also synthesize folic acid, niacin, and pyridoxine. 

Bifidobacterium bifidum
One of the better-known species of probiotics, B. bifidum may be an effective choice for those who are susceptible to allergies. Further, it is known to be a part of the skin’s microbiome and thus can support healthy structure and function of the skin.

Strain specific: Bifidobacterium bifidum MIMBb75 has been shown to be effective for symptoms of irritable bowel. In one study of 122 individuals with IBS, B. bifidum MIMBb75 was found to reduce the global assessment of IBS symptoms by −0.88 points when compared with only −0.16 points in the placebo group. According to the researchers, this strain also significantly improved the IBS symptoms pain/discomfort, distension/bloating, urgency and digestive disorder.

Bifidobacterium longum
Another common species of Bifidobacterium is B. longum. This is one of the very first beneficial bacteria that colonizes the sterile GI tract in newborns; and it is abundant in human breast milk. B. longum stimulates proper immune response and microbial balance by ensuring pathogenic bacteria cannot adhere and colonize.

Strain specific: Bifidobacterium longum BL999 is well-tolerated in infant formula. One study combining this strain with prebiotics (galacto-oligosaccharides and fructo-oligosaccharides) showed that the infants who consumed the synbiotic formula had fewer incidences of constipation and upper respiratory infections than the control group during the seven-month period.



This “encapsulation” of probiotics species and just one strain under each is only one tree in the magical forest teeming with probiotic life. Once you begin to understand the basics, learning more about strains and the research on them is much easier, and helps you choose the best probiotic for your needs.


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