SuperSpecies Profile: Lactobacillus acidophilus

In the worlds of models, stars and heroes – adding “super” as a prefix denotes an exalted class which all aspire to reach but only few do. Believe it or not, the same phenomenon occurs among probiotic species.

There are quite a few superspecies – those with a dizzying number of studies – in vitro, animal and human clinical trials that collectively prove benefit to the human host when consumed. They have gold-standard documentation, characterization, and history of use.

The first superspecies in a coming series is Lactobacillus acidophilus – this is the one that has the longest history of being available as a dietary supplement (there were days when it was primarily sold in capsules and found only in store refrigerators). In general, L. acidophilus creates lactic acid by breaking down carbohydrates, such as lactose found in milk and other dairy foods.

Since those days, L. acidophilus and all of its probiotic relatives have come a long way.

Taxanomy in Brief

As a quick refresher, because probiotics are living entities, they are classified in a system called taxonomy.

It all starts on top with LAB – or lactic acid bacteria -- under which is housed numerous genera within the order of Lacobacilliales, characterized as acid tolerant (others in the order are Enterococcus, Lactobacillus and Streptococcus – all known to reside in the human gut). Lactobacillus is the most comprehensive of the LAB genera with 185 species total!

Bacteria are a world unto their own (as are plants, minerals, fungi and animals). In the world of probiotics, the genus comes first in naming – eg, Lactobacillus, Bifidobacteria -- followed by the species, such as acidophilus. If we look at it like generations, the genus is the grandparent, the species is the parent and the strains are the children of the species and grandchildren of the genus.

Probiotic products (foods and supplements) can be primarily grouped into two categories based on characteristics. One shows stability in products, resistance to bile, tolerance to low pH, antimicrobial production, and adherence to colon lining cells. The other group includes probiotics that have specific health condition benefits such as reducing cholesterol, mediation of immune response and more.

Top L. acidophilus Strains

There are Lactobacillus acidophilus strains that have mountains of research, compared to others, which only have foothills, and others still that haven’t yet erupted.

Lactobacillus acidophilus DDS-1: This strain, first discovered by probiotic research pioneer Dr. Khem Shahani in the late 1950s, was named by him to represent the Department of Dairy Science Number One. Dr. Shahani was intrigued by DDS-1’s ability to exhibit outstanding growth.

DDS-1® has more than 35 years of clinical research (and more ongoing). This clinically supported strain, according to its manufacturer, is “one of the few strains clinically shown to be well-tolerated in virtually all age groups.” It also is unique in that it produces acidophilin, a compound that has been shown to inhibit proliferation of pathogenic bacteria such as E. coli, salmonella and others.

Overall, according to one source, when taken as a dietary supplement, the strain DDS-1 “produces a substance that balances gut bacteria, thereby supporting a healthy gastro-intestinal tract. In addition, DDS-1 helps maintain cholesterol levels already within a healthy range, produces lactase to help reduce lactose intolerance, and manufactures the B vitamins B12, folic acid, and B6 while colonizing the intestinal tract.”

Recent studies of DDS-1 show some condition-specific support. One mouse study, for example, demonstrated that this strain can benefit the elderly gut/digestion. Aging mice that consumed the strain showed that it positively modulated the gut microbiota, which thus improved their metabolic conditioning.

In another study, when tested head to head against three other strains (Bifidobacterium animalis ssp. lactis UABla-12, L. plantarum UALp-05 and Streptococcus thermophilus UASt-09) in several parameters – digestion, adhesion, cytokine release and cell viability, DDS-1, according to the authors, “demonstrated superior survival rates, good adhesion capacity and strong immunomodulatory effect under different experimental conditions.”

This strain has been shown to be potentially useful for individuals who are lactose intolerant. DDS-1, when compared to other strains of L. acidophilus, produces more lactic acid as well as an enzyme, beta-galactosidase, that assists in the breakdown of the lactose into the tolerable sugar galactose that is absorbed and metabolized for energy as glucose is. Further, individuals with lactose intolerance exhibited low levels of beta-galactosidase.

Relatedly, researchers who performed randomized, double-blind, placebo-controlled, crossover study on adults with lactose intolerance sought to determine the impact of four weeks of DDS-1 supplementation on symptoms when given a six-hour lactose challenge at the study’s end. The team found that the probiotic group had statistically significant reductions in symptoms (cramping, diarrhea, and vomiting) compared to those in the placebo from the challenge.

Lactobacillus acidophilus LA-5: Lactobacillus acidophilus (LA-5®) is a well-characterized and well-documented probiotic strain with more than 150 published studies and 60 clinicals.

This gut-colonizing bacterium is an important member of the GI microbiota and has been shown to help protect against incoming pathogens that would be opportunistic to adhere and flourish, causing illness. One study showed that LA-5 acts effectively to vanquish enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection.

Other studies show numerous health impacts when combined with BB-12 (note: this topic will be explored in a later blog). And one investigation successfully integrated L. acidophilus LA-5 in fruit-based ice cream. The researchers wrote, “Results show the presence of a sufficient number of viable organisms [LA-5] in the product for the 10-week period, which would be beneficial to consumers.” This is an example of how food manufacturers are combining good taste in desirable convenience foods with ingredients that provide health benefits.

Lactobacillus acidophilus NCFM: The L. acidophilus NCFM® strain was first identified in the early 1970s at the North Carolina Food Microbiology (NCFM) lab at North Carolina State University, and now has more than 45 clinical trials showing its potent ability to support GI health. This strain is often combined with Bifidobacterium lactis Bi-07 in clinical trials.

Several clinical trials have demonstrated that supplementing with L. acidophilus NCFM (also in combination with Bifidobacterium species) can produce health benefits. For the millions of people dealing with the intensely uncomfortable symptoms associated with functional bowel disorders (FBD), a long-term solution that dramatically reduces bouts and symptoms intensity would be highly welcome. One team sought how the combination featuring L. acidophilus NCFM would fare. The double-blind, placebo-controlled clinical trial gave NCFM along with Bifidobacteria lactis Bi-107 twice daily or placebo for 8 weeks and found that those in the probiotic group experienced improvement in symptoms such as bloating, and those in the irritable bowel syndrome subgroup (33) also reported symptomatic improvements. The authors write that the results support “the role of intestinal bacteria in the pathophysiology of FBD and the role for probiotic bacteria in the management of these disorders.”

Another study showed NCFM’s potential use for healthy young children who may be susceptible to catching a cold in winter. Children (in daycare and school) are known to be afflicted with higher numbers of colds than older kids and adults; and worse, they tend to “share” with their families.

In this double-blind, placebo-controlled study, 326 children aged 3 to 5 took either Lactobacillus acidophilus NCFM or L. acidophilus NCFM combined with Bifidobacterium animalis ssp. lactis Bi-07, or placebo twice daily for 6 months.

Compared to the placebo group, single and combination probiotics reduced fever incidence by 53.0% and 72.7%, coughing incidence by 41.4% and 62.1%, and rhinorrhea incidence by 28.2% and 58.8%, respectively. Additionally, the children taking the probiotics overall had fewer school absences and reduced use of antibiotics.

Lactobacillus acidophilus is a potent probiotic useful for replenishing and sustaining the beneficial microbiota to restore balance. There’s a reason that it shares nomenclature with stars and heroes—this one is a true superstrain!

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