Species Spotlight: Lactobacillus paracasei


OK, first thing is first--let’s get the pronunciation of the species’ surname correct: para-kay-see-eye.

Its famous cousin, L. acidophilus, gets all the attention, it seems. But L. paracasei is an upcoming rock star of the probiotics world. It has been studied wide and deep, and has been found to provide beneficial impact on several areas of human health.

L. paracasei is part of the Lactobacillus casei group (LCG), which also includes L. rhamnosus. These, according to researchers, represent some of the most studied species due to their commercial, industrial and applied health potential. They have also been found to produce many bioactive metabolites which can confer host benefits when consumed.

Genetically, “All L. paracasei strains (except strain Lpp125) have a 7-gene cluster with the pilin-specific spaBCA genes, and all have the spaDEF genes; this suggests that all L. paracasei strains have the potential to synthesize pili which may play a role in mucus binding, adhesion or biofilm formation.” Primarily, this means that L. paracasei helps reinforce the healthy structure of the GI tract, notably its protective layers that thwart incoming invaders and non-essential matter.

L. paracasei is a species that is composed of gram-positive lactic acid bacteria. Other strains in this vein include 87:002, BS1060 and CNCM 1-1572 (alternatively known as LP-DG®). L. paracasei strains are indeed being scrutinized more in the lab and in living organisms; they are increasingly found to exert more than one benefit—L. paracasei seem to be adept multitaskers.

For example, LP-DG® has immunostimulatory properties, promotes intestinal homeostasis (healthy balance), reduces inflammation and vanquishes invading pathogenic bacteria.

As another example, the strain NTU 1010 and its fermented byproducts are effective for managing blood pressure, cholesterol and immunomodulation and alleviation of allergies.

Boosting Immune Activity

Members of the L. paracasei family are particularly adept at supporting immune function as well as digestive function, via a wide range of actions. Of particular reassurance to parents, one randomized controlled study showed that administration of L. paracasei (CBA L74) in milk or rice reduced and even prevented common infection diseases in children attending daycare. The authors believed the probiotic helped stimulate both innate and developed immunity.

More detailed mechanistic studies were performed in mice to reveal how L. paracasei strains impacted and interacted with immune cells. For example, one study showed that L. paracasei (NTU 101) helped the mice overcome E. coli infection through downregulating expression of toll-like receptors on macrophages and pro-inflammatory cytokines, inhibiting inflammation, which modulated the immune response. Another investigation showed that mice that were administered the same strain showed significantly enhanced lymphocyte and antibody production.

Another pathogenic bacteria, salmonella, meets a challenge in L. paracasei. One study showed that L. paracasei CNCM I-4034 enhanced innate immunity, reducing pro--inflammatory cytokines and chemokines in the human intestine containing salmonella.

Among 85 strains of L. paracasei studied for immunomodulation, one strain, L. paracasei MoLac-1, most strongly induced expression of interleukin-12. This glycoprotein helps fight infection by functioning as a “bridge between the early non-specific innate resistance and the subsequent antigen-specific adaptive immunity,” according to the study authors.

Improvement of GI Function

We are not only what we eat, but what we absorb, and digestion is the critical foundation of good health. L. paracasei (among many other probiotic species) works exceptionally well to balance digestive function.

First, it was found to improve the populations of microflora residing in the gut. L. paracasei KW3110 was shown to increase the number of Bifidobacteria and Lactobacilli. Even after one week post-supplementation, this strain was still found in 50% of the volunteers. Its relative, L. paracasei LC01 was shown to inhibit fecal E. coli and increase members of the genera Lactobacillus and Bifidobacterium, suggesting a beneficial effect on bowel function in young adults.

In mice, colonization by L. paracasei NCC2461 was shown to induce changes in the metabolic profiles of all intestinal tissues (except for the colon), which is “consistent with modulation of intestinal digestion, absorption of nutrients, energy metabolism, lipid synthesis and protective functions,” the authors concluded.

In addition, probiotics such as those in the L. paracasei species can help improve the structure of the intestinal barrier, which ensures that what needs to be absorbed into the bloodstream is—and what isn’t, is kept out. For example, one study investigated how L. paracasei 01 in a fermented milk affected the intestinal epithelial (lining) cells. Specifically, this strain exhibited significant protective effects. The authors write, “The protecting mechanisms [of L. paracasei] involve promoting intestinal epithelial cell growth and intestinal epithelial integrity to strengthen the intestinal barrier against chemical and inflammatory stimuli-induced damage. Inhibition of inflammatory cytokines and chemokine … also contributes to the beneficial effects of this product on epithelial function.”

The intestines can become inflamed from various causes, one such being inflammatory bowel disorders (IBS, Crohn’s, diarrhea, etc.). Of the inflammatory bowel disorders, IBS alone affects approximately between 10 and 15% of adults. Noting that previous studies have shown specific probiotics may relieve symptoms and promote balance in cases of inflammatory bowel disorders, researchers looked at L. paracasei ST11 (CNCM 1-2116), already known to be a potent strain with immune modulation abilities. In this study of mice with colitis, the researchers concluded that strains of L. paracasei “harbor worthwhile in vivo immunomodulatory properties to prevent intestinal inflammation.”

Interestingly, in those individuals taking proton-pump inhibitors (antacids) that induce uncomfortable bowel symptoms, L. paracasei F19 supplementation was shown to prevent onset of bloating, flatulence, abdominal pain and imbalanced bowel activity. This particular strain was also researched for its impact in individuals with uncomplicated diverticular disease; here, the study team found that the strain combined with a high-fiber diet “is effective in reducing abdominal bloating an prolonged abdominal pain” in these individuals.

And, as any irritable/inflammatory bowel disorder will induce diarrhea and constipation, L. paracasei strains have been studied specifically for their effects in these issues as well. As part of a synbiotic formula, L. paracasei B21060, was shown to be effective in a placebo-controlled trial of 55 children with acute diarrhea.

On the opposite end, 80% of study participants who consumed artichokes enriched with L. paracasei experienced satisfactory relief of symptoms of constipation.


L. paracasei strains have been widely studied and have more “super powers” than what’s tallied here; and these will presented in a future blog. In the meantime, you can find L. paracasei easily available online and in stores. LP-DG® for example, is available as a micro-shot in two formulas, one for immune boosting and one for digestive support.

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