Many of us have turned to probiotics to help us balance our gut microbiome and boost our good gut bacteria. One type, the lovely Lactobacillus, has long been employed as a traditional probiotic (think fermented dairy products,) and more recently as commercially available supplements in combination with other probiotic strains. Still, what strain is individually good for you? Here, we delve deeper into specific Lactobacillus strains, giving you an overview of their therapeutic abilities and where you can find them.
Some of the most extensively studied and widely used probiotic strains of bacteria are members of the Lactobacillus genus. These make up a major part of the larger lactic acid bacteria group, which are Gram-positive and produce lactic acid during carbohydrate fermentation1,2. The metabolic versatility of this genus results in an ability to colonise a variety of habitats such as plants, animals, and raw milk, thus making it the largest of the Lactobacillaceae family with over 100 species and subspecies2.
The Lactobacillus group is large, highly diverse, and shows great variation
The versatility of Lactobacillus and their ability to colonise various niches is reflected in the large phenotypic and genotypic variation within the genus. Due to their diversity, attempts to classify the genus into phylogenetic groups have often been revised, but here are the main established groups2,3:
- L. acidophilus — Species from the acidophilus group play an important role as starter cultures in dairy and vegetable fermentation (e.g., L. helveticus and L. delbrueckii, respectively). Some other strains play a key role in the gut microbiome to benefit human health and nutrition.
- L. casei — The most well-known species are L. paracasei and L. rhamnosus, which are commonly found in cheeses. L. paracasei and L. caseiare also commensal within the animal/human gastrointestinal (GI) tract.
- L. plantarum — Subspecies from this group are considered food-grade because of its long and documented history of safe use in fermented foods such as in dairy, meat, and vegetable products. These have also been shown to survive gastric transit and colonise the gut to live beneficially within the GI tract.
- L. reuteri — At least 6 species within this group can be isolated from sourdough. One supspecies, L. fermentum, has also been isolated from vegetable and dairy ferments. Members of this group are also known to produce the antimicrobial compounds reuterin and reutericyclin, which have potential applications in food preservation and as probiotics.
- L. buchneri — This large and heterogenous group are mostly linked to food fermentation, such as vegetable fermentation, sourdough, and kefir grains.
It’s no surprise, then, that these bacteria have been used for decades in food production. The acidic conditions created from the production of lactic acid, and its ability to produce antimicrobial bacteriocins, lends to its capability for food preservation – fermented vegetables and meats are a good example of this2. Lactobacillus are also able to produce exopolysaccharides and certain aroma compounds to enhance the flavour, texture, and nutrition of low-fat products, which makes it ideal for use as starters or complementary cultures for several cheese varieties, sourdough breads, and in wine and beer2,4.
Lactobacillus are extensively used as probiotics in food
Though Lactobacillus also exist commensally within normal gut microbiomes, the ingestion of certain strains as probiotics can boost their benefits. In short, Lactobacillus probiotics can contribute to a balanced microbial ecosystem by aiding nutrient digestion and absorption, metabolise indigestible compounds, inhibit pathogens, and stimulate the immune system5,6. Those from the acidophilus group in particular are extensively studied and known to contain probiotic strains.
Though lactobacillus also exist commensally within normal gut microbiomes, the ingestion of certain strains as probiotics can boost their benefits.
Dairy products are the most common food carriers of probiotics, most of which contain L. acidophilus, L. gasseri, L. helveticus, L. johnsonii, L. (para)casei, L. reuteri, L. plantarum, L. rhamnosus, L. fermentum2. In the supermarket, you can find them in pasteurized milk, ice cream, fermented milks, cheeses, baby feed milk powder, and probiotic yoghurt – there are many non-dairy versions, think coconut and soy-based yoghurts etc!
Lactobacillus probiotics also show evidence of therapeutic behaviour in many pathologies
Various studies show that a number of illnesses and pathologies can be induced when a healthy microbial equilibrium becomes imbalanced from the lack of these commensal bacteria7. This phenomenon, termed dysbiosis, is particularly associated with illnesses in the GI.
Numerous studies, both in vitro and in vivo, have shown that prolonged administration of Lactobacillus (as supplements) can prevent or reverse adverse effects from dysbiosis by positively modifying the population of the gut microbiome8. An overview of the strains, their associated therapeutic effects, and possible food carriers are described in the table below.
|L. acidophilus||Irritable Bowel Syndrome (IBS), radiation- and antibiotic-induced diarrhea, necrotizing enterocolitis, vulvovaginal candidiasis, hepatic encephalopathy, serum cholesterol and lipids||Yoghurt, fermented soy products (miso, tempeh)|
|L. delbrueckii bulgaricus (L. bulgaricus)||Antibiotic and C. difficile-associated diarrhea, immunomodulation||Yoghurt (in combination with Streptococcus thermophilus)|
|L. johnsonii||H. pylori carriage, modulation of allergic disorders, UV-induced skin damage||Fermented dairy products|
|L. reuteri||Mediating pathogen resistance (reuterin and reutericyclin compounds used in food preservation), immunomodulation, diarrhea, respiratory infections||Sourdough, vegetable and dairy ferments|
|L. reuteri 55730, L. reuteri 17938||Infant colic|
|L. reuteri atcc 17938, atcc 4659||Necrotizing enterocolitis|
|L. reuteri 6475, L. reuteri 23272||Colitis, osteoporosis|
|L. casei strain Shirota, L. paracasei B21060, L. paracasei ST11, L. casei DN-114001||Diarrhea induced by antibiotics, C. difficile, Norovirus, norovirus gastroenteritis||Fermented foodstuffs (e.g. wine, kimchi, pickle), fermented or raw dairy (e.g. cheese)|
|L. Paracasei subsp. paracasei F19, L. casei subsp. DG||Diverticulitis|
|L. paracasei B21060||IBS|
|L. casei||Necrotizing enterocolitis, diabetes, major depressive disorders|
|L. casei strain shirota||Prevention of high-fat diet-induced insulin resistance, chronic kidney disease, upper respiratory tract infections|
|L. plantarum 299v||IBS, cardiovascular disease risk, acute pancreatitis sepsis, respiratory tract infections, facilitating iron absorption, inflammatory suppression||Vegetable, meat and dairy products|
|L. plantarum TENSIA (DSM 21380)||Antimicrobial and antihypertensive properties, lowering BMI and lipid levels|
More and more evidence show the beneficial effects that lactobacillus probiotics have on health and nutrition. If you’re interested in how they might help your health, GUTXY’s microbiome testing kits give personalised recommendations for the specific probiotic strains that work just for you.