Probiotic Strains, Species and Definitions

Major Species of Probiotics


There are two important probiotic strains that are essential for health. They include the Lactobacillus species and the Bifidobacterium species. When selecting a probiotic supplement, be sure to choose one with both. Additionally, each species of contains several beneficial strains. The best probiotic supplements will carry at least 10 strains. In this section, you’ll find descriptions for the two major species as well as several strains within those species. Each are beneficial for your gut and overall health.

Lactobacillus Species

Lactobacillus is one of the most important probiotic species. This is a type of bacteria with multiple strains in the genus. They live in in the digestive, urinary, and genital tracts of humans. Lactobacillus is responsible for producing lactase which is an enzyme that breaks down lactose (sugar in milk). It is also responsible for carbohydrate fermentation within the gut. This process also produces lactic acid which creates an acidic environment within your gut to ward off unwanted microorganisms that thrive in an alkaline environment.

The lactobacillus species consists of several strains. Anti-inflammatory and anti-cancer activities are some of the potential therapeutic properties. Following are some of the most important strains with their benefits:

  • Lactobacillus Acidophilus. Lactobacillus acidophilus is one of the most widely known strains. As a vital bacterial strain for proper function of the human body, L. acidophilus plays an important role in digestive health and immune function. Women who supplement with this probiotic may experience a substantial reduction in unpleasant digestive issues, including bloating, gas, diarrhea, IBS, lactose intolerance, and leaky gut syndrome. L. acidophilus also has anti-allergy benefits and the ability to support the immune system so it can better fight off infection.

    Absorption of nutrients is made easier with Lactobacillus Acidophilus. Immune, urinary, and genital tracts health – especially vaginal health in women – may be boosted.

  • Lactobacillus Casei. Overall digestion, cholesterol lowering, diarrhea control are some of the benefits of Lactobacillus Casei.

  • Lactobacillus Lactis. This probiotic strain is mostly used for diarrhea and treating chronic bowel inflammation.

  • Lactobacillus Paracasei. By boosting the immune system and energy levels, this is one of the best strains added to probiotic supplements as it’s the key to digestive function. Research has shown that Lactobacillus Paracasei may also help in fighting infections. Liver health is also promoted with this probiotic strain.

  • Lactobacillus Plantarum. A unique probiotic that offers exceptional benefits to women. This probiotic strain produces natural antibiotics that can target infection and help increase overall immunity. L. plantarum is also widely renowned for its ability to reduce the symptoms of digestive issues such as IBS. In one research trial, 95% of participants experienced a substantial reduction in IBS-related symptoms with supplementation of L. plantarum. This probiotic can also reduce flatulence, lower permeability of the intestine, and fight off pathogens in the digestive tract.

    Overall digestion and immune health benefits can be obtained from Lactobacillus Plantarum. Lactobacillus Plantarum has also been shown through studies to help with gastrointestinal side effects commonly associated with antibiotics.

  • Lactobacillus Rhamnosus. As a key contributor to digestive, bladder, and vaginal health, Lactobacillus rhamnosus plays a vital role in women’s health. This particular strain of probiotic has an anti-inflammatory effect within the body, and it is able to inhibit the growth and adhesion of various harmful pathogens that can lead to infection. L. rhamnosus can also help to prevent yeast infections in the vagina and reduce the risk of women contracting bladder infections.

  • Lactobacillus fermentum. As medical technology advances, issues that affect the aging population have become an important topic of discussion when it comes to healthy living and quality of life. Studies have shown that the probiotic strain of Lactobacillus fermentum assists with the function of antioxidant enzymes and can boost immune response. The increased immune ability from supplementation with this probiotic helps the person to resist a number of types of infection and can contribute to a healthy aging process. Additionally, women can receive benefit from L. fermentum supplementation as studies have shown it can reduce the colonization of harmful bacteria and yeast in the vagina.

  • Lactobacillus bulgaricus. For many women, digestive issues can have a detrimental effect on their daily quality of life. Over the last several decades, research has continued to support the positive effect that specific probiotic strains have on managing symptoms of common intestinal conditions. Lactobacillus bulgaricus is a widely studied probiotic that has been shown to have a number of benefits when taken regularly. In addition to increasing overall immune function, this probiotic can decrease common symptoms of IBS, improve leaky gut syndrome, and help women manage their cholesterol levels.

  • Lactobacillus gasseriiBacterial vaginosis is the most commonly diagnosed urogenital infection in women of pre-menopausal age. Typically, this infection occurs when pathogens are more prevalent than the naturally protective lactobacilli organisms. There are several types of lactobacillus strains that contribute to vaginal health, and L. gasserii is an essential component to the body’s natural defenses. Medical research has shown that when lactobacilli are the dominant microbe in the urogenital system, yeast and other pathogens experience inhibited growth.

  • L. reuteri. Well-known for its role in women’s health, Lactobacillus reuteri is an essential bacteria to balance a number of different body systems. Like most probiotics, L. reuteri plays a key role in intestinal and digestive health, and numerous studies have shown improvement of unpleasant digestive symptoms with regular supplementation of probiotics. Additionally, this specific strain has been linked to the control of vaginal yeast and prevention of bladder infections - common issues that women face.


Bifidobacterium Species

Another major probiotic species is Bifidobacterium. Like the Lactobacillus series, it contains several strains in its genus. In humans, they inhabit the gastrointestinal tract, the vagina of women, and the mouth. It covers the walls of your colon to help ward off invasively harmful bacteria and microorganisms such as yeast. Bifidobacterium also produces lactic acid which provides up to 70 percent of the energy required by the cells that line the walls of your colon. This process naturally protects you’re gastrointestinal tract. Production of Vitamin B-complex and Vitamin K are also produced from Bifidobacterium.

Like the Lactobacillus species, Bifidobacterium boosts your immune system. It consists of several beneficial strains:

  • Bifidobacterium Bifidum. When you were born, this probiotic strain made up 95% of your intestines and protected you from germs. Bifidobacterium attaches to the lining of your colon to help you digest sugars. It also protects your blood from germs and toxins with nutrient absorption and overall digestion. Occasional diarrhea relief is also another benefit. Recent studies have shown this particular strain to reduce the incidences of colds and flu.

  • Bifidobacterium Breve. This powerhouse strain helps alleviate bloating, gas, diarrhea, and constipation. It also inhibits E. coli and suppresses candida (yeast) which can make you very sick.

  • Bifidobacterium Lactis. This strain is one of the most versatile and hardest working as it supports healthy cholesterol levels, eases ulcerative colitis, and combats the effects of Celiac disease.

  • Bifidobacterium Longum. Impressively, Bifidobacterium Longum benefits your body by helping gastrointestinal discomfort caused by stress and attenuating anxiety.

  • Bifidobacterium infantis inhabits the intestinal tract of both children and adults. Research has shown that increased numbers of B. infantis in the digestive track can boost women’s natural defense mechanisms against the common culprits of an IBS flare. This powerful probiotic has also been found to produce beneficial acids that have the potential to reduce the prevalence of harmful colon bacteria. This can be particularly useful for women who suffer from symptoms of Irritable Bowel Syndrome (IBS). 


Other Species


Streptococcus thermophilus. This is a well-researched strain of probiotics that can have a number of positive health benefits for women. Like most probiotics, S. thermophilus can improve digestive concerns that include diarrhea, leaky gut, and symptoms of IBS. This strain also produces lactase which can aid in the digestion of dairy for those with a sensitivity to lactose. In addition to the digestive relief found with this probiotic, those who take it may experience increased immune function which leads to a greater resistance to common infections.



Lactobacillus Series


Bifidobacterium Series


Bifidobacterium Infantis


Vaginal Microbiota and the Use of Probiotics


Lactobacillus fermentum’s immune benefits show ‘potential to augment healthy aging’


Lactobacillus Bulgaricus Probiotic Information


Streptococcus thermophilus: A Healthy Probiotic Strain


What is Probiotic S. Thermophilus?


Acidophilus Facts & Benefits


Researched Benefits of L. Plantarum


Probiotics for Women’s Health: The Story of Lactobacillus Rhamnosus GR-1 and Lactobacillus Reuteri RC-14's_Health:_The_Story_of_Lactobacillus_Rhamnosus_GR-1_and_Lactobacillus_Reuteri_RC-14


10. Oral use of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women.