Two species of bacteria—Lactobacillus and Bifidobacterium—are the most commonly used probiotics, but other species are also used.

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With the latest research showing that the benefits of probiotics extend far beyond digestion, the question is not whether you should be taking probiotics, but which probiotics, how much, and how often. As discussed in a previous post, probiotics are live microbes that help the healthy bacteria residing within you to thrive and by doing so they improve many aspects of health. When consumed as food or supplements, the best probiotics can improve digestive health, enhance immune function, squelch allergies, and more.

The best probiotic supplements will list the strain, including genus, species, and letter/number designation

There are many beneficial probiotics from which to choose. Two species of bacteria—Lactobacillus and Bifidobacterium—are the most commonly used probiotics, but other species are also used. As discussed in part 1, each probiotic is officially identified by its strain—its genus, species, and letter/number designation. While all probiotic strains, by their very definition, promote health, each particular strain is thought to have its own set of specific effects in the body.

Choosing the best probiotics supplements means matching the strain to your particular condition

To get the most benefit from your probiotic, you need to choose a high-quality supplement containing the strains most likely to treat your personal condition. With hundreds of strains of Lactobacillus, Bifidobacterium, and other species being studied, as well as a dizzying array of probiotics on store shelves (often containing numerous species and strains in widely varying amounts), choosing the best probiotic  supplements and knowing how to take them for your particular condition can be difficult.

What are the best probiotics supplements that have been clinically researched, found to be effective, and are available to consumers?

While it is not possible to comprehensively review all the well-researched and high-quality probiotics strains here, the following is a short list of some of the best probiotic supplements in terms of the most highly researched strains, their brand names, the companies that sell them, the health conditions for which they were found effective, and the recommended therapeutic dose:

List of some of the best probiotic supplements by strain:

Lactobacillus rhamnosus GG, which is known as Lactobacillus GG and is sold under the brand name Culturelle®, is a well-researched strain of lactobacillus that has been shown to be effective for numerous conditions. Most of the research on Lactobacillus GG has been performed in children and infants. It has been shown to prevent eczema[1], prevent and treat diarrhea[2], treat abdominal pain associated with IBS[3], and decrease upper respiratory tract infections (the common cold) in children attending day care centers.[4] The typical dose used in studies in children is 10 billion colony-forming units (CFU) once per day. Adults can take 10 billion CFU twice per day. The length of time you should take this dose depends on the condition but is typically one to three months. It is safe to take indefinitely.

VSL#3 is the brand name of a combination probiotic supplement sold by the pharmaceutical company Sigma Tau. VSL#3 is a mixture of proprietary strains of the following species:

• Streptococcus thermophilus
• Bifidobacterium breve
• Bifidobacterium longum
• Bifidobacterium infantis
• Lactobacillus acidophilus
• Lactobacillus plantarum
• Lactobacillus paracasei
• Lactobacillus delbrueckii, subspecies bulgaricus

VSL#3 is a well-researched probiotic and is very potent. It is sold in a regular-strength (450 billion CFU per sachet) as an over-the-counter probiotic supplement and is also sold as a prescription in double-strength form. Most of the VSL#3 research has been conducted in adults with the autoimmune condition ulcerative colitis and it has been found to significantly improve colitis symptoms in the majority of patients.[5] The therapeutic dose for ulcerative colitis is very high, up to 3,600 billion CFU per day. VSL#3 has also been studied in adults with IBS, but while it was found to reduce bloating by 39% in one study[6] and flatulence by 25% in another[7], it did not improve abdominal pain or other IBS symptoms. If you have IBS characterized by abdominal bloating or bad gas, this probiotic is worth a try as a 30-day treatment, taking ½ to one sachet per day. If you have ulcerative colitis, it is recommended you work with your healthcare practitioner to determine a proper VSL#3 dosing schedule in which you slowly ramp up the dose. VSL#3 has also been found to enhance the healing of stomach ulcers and to prevent diarrhea associated with taking antibiotics or undergoing chemotherapy.

Lactobacillus plantarum 299v, a powerful, well-researched strain of lactobacillus found in “UltraFlora™ Intensive Care” by Metagenics and in “Digestive Health Probiotic” by Nature Made is one of the best probiotics for the symptoms of IBS, especially for reducing the frequency and intensity of both abdominal pain and bloating [8]. It has also been shown to help normalize the frequency of bowel movements in those with IBS. The therapeutic dose is 10 billion CFU per day, but higher doses may be even more helpful at ameliorating IBS symptoms. Lactobacillus plantarum 299v has also been found to improve loose stools and nausea associated with taking antibiotics.

Bifidobacterium lactis HN019 is a specific strain of bifidobacterium which has been found to help speed up the frequency of bowel movements as effectively as fiber, simultaneously improving symptoms of constipation, irregular bowel movements, and flatulence.[9] The most effective dose in this study was 17.2 billion CFU per day, but lower doses may also be effective for constipation. Bifidobacterium lactis HN019 has also been found to boost the functioning of immune system in studies, increasing the numbers of lymphocytes and natural killer cells in the blood.[10] It may therefore be helpful in reducing the incidence of common infections, but this has not yet been studied in clinical trials. Some of the best probiotic supplements containing this strain are ProbioMax DF™ by Xymogen and in UltraFlora™ Acute Care by Metagenics.

Bacillus coagulans, formerly known as lactobacillus sporogenes, is another well-searched probiotic. This particular type of probiotic is very hearty and needs no refrigeration. A patented strain of Bacillus coagulans (GBI-30, 6086) sold as Digestive Advantage® Intensive Bowel Support by Schiff was found to be safe and effective for the relief of abdominal pain and bloating for patients with IBS.[11] Another probiotic by Schiff, combining this strain of Bacillus coagulans with natural digestive enzymes, was also found to improve gastrointestinal symptoms in adults with intestinal gas-related symptoms (abdominal pain, distention, flatulence) but no gastrointestinal diagnosis, such as IBS, to explain the symptoms.[12]

Start with a trial of some of the best probiotic supplements matched to your condition

The probiotic strains discussed above are a good place to start if you feel overwhelmed by the vast array of probiotics on the market and want an easy way to choose only the best probiotic supplements. There are plenty more well-researched probiotic strains and combinations, so this list is by no means meant to be a comprehensive one. The majority of the probiotics listed above are high-potency formulations which are generally not meant to be taken long-term (more than three months), although, with their excellent safety records, probiotics  could be taken indefinitely in almost all cases.

[1] Lancet. 2003 May 31;361(9372):1869-71.

[2] BMJ. 2007 Aug 18;335(7615):340.

[3] Pediatrics. 2010 Dec;126(6):e1445-52.

[4] Clin Nutr. 2010 Jun;29(3):312-6.

[5] Am J Gastroenterol. 2005 Jul;100(7):1539-46.

[6] Aliment Pharmacol Ther. 2003;17:895-904.

[7] Neurogastroenterol Motil. 2005 Oct;17(5):687-96.

[8] World J Gastroenterol. 2012 August 14; 18(30): 4012–4018.

[9] Scand J Gastroenterol. 2011 September; 46(9): 1057–1064.

[10] Am J Clin Nutr. 2001 Dec;74(6):833-9.

[11] Postgrad Med. 2009 Mar;121(2):119-24.

[12] BMC Gastroenterol. 2009 Nov 18;9:85.

Originally published in 2013.