There are many different kinds of probiotic supplements today, largely because there are so many different types of beneficial bacteria that reside within your gastrointestinal tract. As part of your foundation program, we recommend staying with the two most common and proven genras lactobacillus and bifidobacterium. Here are some of the following types of beneficial bacteria commonly supplied today in probiotic supplements.

Lactobacillus acidophilus–Many studies confirm the safety and efficacy of this bacteria for prevention of infectious diseases and favorably altering the intestinal microflora balance, inhibiting the growth of harmful bacteria, promoting good digestion, boosting immune function, and increasing resistance to infection. The lactobacillus is widely used in many probiotic supplements. Lactobacillus primarily works in the small intestine. This one should be part of every supplement program. Be sure to read our shopping guide so that you can be sure you purchase a strain that is known to colonize in the human gastrointestinal tract.

Lactobacillus bulgaricus–These friendly bacteria help reduce severity of childhood intestinal diseases, including diarrhea. This bacteria is found commonly in yogurt, and considered safe.

Latobacillus plantarum–This microorganism, prevalent in nearly all plant life, was identified in the human body during a study at Sweden’s Lund University on the species of lactobacilli residing in the human gastrointestinal tract and subsequently those that are most implantable. In one part of the study, subjects ingested a variety of strains to determine which had successfully implanted. Five species persisted at least one day after administration, with Lactobacillus plantarum being the most dominant. Numerous studies have been conducted to document its health benefits and safety.

Lactobacillus brevis–To characterize and select lactobacillus for properties that would make them a good alternative to the use of antibiotics to treat human vaginal infections, 10 lactobacillus strains belonging to four different lactobacillus species were analyzed for properties relating to mucosal colonization or microbial antagonism (adhesion to human epithelial cells, hydrogen peroxide production, antimicrobial activity towards Gardnerella vaginalis and Candida albicans and co-aggregation with pathogens). Three strains (including Lactobacillus brevis) “showed optimal properties and were, therefore, selected for the preparation of vaginal tablets,” say researchers from the Institute of Microbiology, University La Sapienza, Roma, Italy.“ The selected strains adhered to epithelial cells displacing vaginal pathogens; they produced high levels of [hydrogen peroxide], coaggregated with pathogens and inhibited the growth of G.vaginalis.” Additional studies confirm that this strain can induce programmed cell death in leukemic cells. This L. brevis is considered safe, as noted by its inclusion on the Food and Drug Administration’s generally recognized as safe (GRAS) list for microorganisms used in production of foods.

Lactobacillus caucasicus–Kefir dates back many centuries to the shepherds of the Caucasus Mountains, many of which live to be happily active at over 100 years of age. They discovered that fresh milk carried in leather pouches would occasionally ferment into an effervescent beverage. For most of recorded history, kefir was scarcely known outside the Caucasian Mountains. Kefir received renewed interest in the West when it was found to be a useful therapeutic treatment for patients in sanitariums. Traditionally, microflora in kefir include Lactobacillus caucasicus.

Lactobacillus fermentii–Although little information is available on this particular bacteria, it is known to play a role in vitamin B12 metabolism; it is included on the FDA’s GRAS list.

Lactobacillus helveticus–A considerable amount of research has been conducted to study the health benefits of fermented milks. Research on the health effects of a pasteurized sour milk, which is fermented by a starter culture containing Lactobacillus helveticus as the predominant microorganism, indicated clear evidence for the involvement of fermented compounds that have antihypertension properties via angiotensin-I converting enzyme inhibitory peptides. Again, this bacteria has centuries of traditional use in fermented foods, testifying to its absolute safety. Researchers from the Key Centre for Applied and Nutritional Toxicology, Melbourne, Australia, note, “Members of the genus Lactobacillus are most commonly given safe or generally recognized as safe (GRAS) status.

Lactobacillus leichmannii–Several studies have been conducted on the natural microbiological flora of sourdoughs from around the world. For German sour rye,the dominant lactobacilli included L. leichmannii. The lactobacilli secrete an antibiotic cycloheximide, which “sterilizes” the dough since it kills many (but not all) pathogenic organisms. Traditional uses confirm its safety.

Lactobacillus lactis–This probiotic bacteris has been shown to be inhibitory to spoilage bacteria in foods at refrigeration temperatures. This is primarily due to its production of hydrogen peroxide. In fact, this beneficial bacteria “can exert inhibitory action on E. coli O157:H7 at refrigeration temperatures and it may be possible to add the lactobacilli to poultry carcasses in the early stages of processing (i.e., chill tank) to exert control of this pathogen,” note researchers. It is commonly found in the human intestinal tract. The FDA considers L. lactis (now considered a member of the bifidobacterium family) to be GRAS.

Lactobacillus casei–Discovered at least as early as 1935, this organism has been used by the Japanese food company Yakult Honsha in commercial products in Japan since 1955. L. casei been shown to implant well in the gastrointestinal tract in human trials, according to N. Yuki of the Yakult Central Institute for Microbiological Research, Tokyo, Japan. This has beneficial effects on cholesterol when studied in the laboratory. It has GRAS status.

Bifidobacterium bifidum–This probiotic bacteria has excellent immune-strengthening properties, especially for children, according to researchers at the Infectious Disease Department, Children’s Hospital of Buffalo, State University of New York. It is GRAS.

Bifidobacterium longum, Bifidobacterium infantis–Probiotic bacteria which offer many health benefits. These are GRAS. Note: There are other probiotic bacteria which are used in probiotic supplements and are GRAS.