Selection criteria for probiotic supplements

Townsend Letter for Doctors and Patients, Feb-March, 2003 by Dr. S.K. Dash

All probiotic products are not alike and do not have similar nutritional and therapeutic values. The name probiotic does not mean anything unless it contains the right strain, in the right amount, in the right formulation and in the right condition (viable) for the intended use.

For this reason one needs to know the strain, its viability, implantation criteria, and other features and health benefits.

Strain Selection

Lactic acid bacteria have a long history of safe use in dairy products. However, some probiotic supplements now contain bacteria, which have no record of safe use in humans or even animals. There are instances of probiotic supplements containing soil bacteria that are not normal inhabitants of the human gastrointestinal tract. These cultures may potentially be pathogenic. It is imperative to select bacteria for incorporation in probiotic supplements that are on the GRAS (Generally Recognized As Safe) list. For example, Lactobacillus acidophilus species and some Bifidobacterium species are considered GRAS. Safe, proven cultures are your first and most important criteria for selection.

Any new bacterial culture that has no history of prior safe use in humans should be subject to toxicological studies prior to incorporation in any probiotic supplements. The bacterial strains used in a superior probiotic supplement should play an important role in:

* Colonization within the intestinal, respiratory and urogenital tracts

* Cholesterol metabolism

* Inhibiting carcinogenesis, directly or indirectly, by stimulation of the immune system

* The metabolism of lactose, the absorption of calcium and the synthesis of vitamins

* Reduction of yeast and vaginal infection

* Constipation and diarrheal diseases

* Gastritis and ulcers

* Acne and skin problems

Additionally, the culture should adhere to the intestinal walls and proliferate. The probiotic strain must be proven to survive stomach acids in live human subjects. And of course, it should produce natural antibiotics, lactic acid and hydrogen peroxide and inhibit pathogenic bacteria such as:

Bacillus subtilis

Serratia marcescens

Bacillus cereus

Proteus vulgaris

Bacillus stearothermophilus

Escherichia coli

Streptococcus faecalis

Salmonella typhosa

Salmonella schottmuelleri

Streptococcus faecalis var liquifaciens

Shigella dysenteriae

Streptococcus lactis

Shigella paradysenteriae

Lactobacillus lactis

Pseudomonas fluorescens

Lactobacillus casei

Pseudomonas aeruginosa

Lactobacillus plantarum

Staphylococcus aureus

Lactobacillus leichmannii

Vibrio comma

Klebsiella pneumoniae

Sarcina lutea

Source: us Patent #3,689,640 In Vitro Antibacterial Activity of DDS-1 Lactobacillus Acidophilus.

Not all strains of Lactobacillus acidophilus and other probiotics are acid-resistant. Selecting acid-resistant strains of L. acidophilus and other probiotics is the key to the success of the probiotic supplement. It is important to remember that enteric coating of bacteria is a poor and unproven substitute for actual acid resistance. Stay away from enteric coated cultures for a few reasons. One is that no studies show that they work. In nature these cultures are not enteric coated. The process of coating these live cultures with a protective layer may in fact kill them or reduce their viability. If these cultures are supposed to get into the intestinal tract on their own and be acid resilient, the whole process of enteric coating is suspect.

Probiotic Supplements with Multiple Bacteria

Some probiotic supplements now contain several different cultures; many of these bacterial cultures have no safe use history in human health and nutrition. These bacteria may be antagonistic to each other and may alter the gut flora in an undesirable way. So it should not be believed that if one bacterium is good, numerous cultures combined together are even better. To the contrary, a few select cultures have been proven beneficial and almost all the others are yet to be proven.

L. acidophilus and Bifidobacterium species are normal inhabitants of the human gastrointestinal tract and are GRAS. Probiotic formulations containing these beneficial bacteria along with prebiotic fructooligosaccharides (FOS) are considered safe and offer many health benefits described earlier.

Manufacturing

The manufacturing process used to produce microorganisms for use in probiotic supplements plays an important role in the viability of the culture. The medium, the temperature and other associated factors influence the viability and identity of the microorganisms. If the probiotic supplements do not contain the same microorganisms with the same viability, they will not offer the same, consistent, good results. Also make sure that the probiotic culture has not itself been contaminated with other harmful bacteria during manufacturing process and packaging. Make sure the company manufacturing the product has a strong history of providing proven safe cultures.

Viability

The viability of probiotics is not only strain-dependent but is also influenced strongly by their physiological and chemical environment. For example, probiotics in liquids including milk and yogurt, do not normally survive longer than a few weeks.