Among nutraceutical suppliers, much attention is given to scientifically identifying, validating and consistently delivering the health benefits of botanical extracts and other bioactive compounds. These principals also are being applied to probiotics, defined by Guarner & Schaafsma1 as "living microorganisms, which upon ingestion in certain numbers, exert health benefits beyond inherent basic nutrition." Advances in genome research will lead to a future in which probiotics will consistently deliver desired health benefits.
In 1907, Nobel Laureate Eli Metchnikoff put forth the theory that intestinal colons contain putrefactive bacteria and that by consuming fermented milk, lives would be longer and more disease-free.
Today, good scientific evidence exists to support the ability of probiotics (whether living) to increase a body's resistance to enteric pathogens, speed recovery from antibiotic-associated diarrhea, reduce hypertension, and assist with lactose digestion. Great scientific evidence supports their ability to stimulate the immune system and improve urinary and vaginal tract health.2 The gastrointestinal tract is, in fact, the most powerful immunological organ in our bodies.
Backed by extensive investigation, most of the scientific community accepts probiotic benefits. However, there is not yet unequivocal proof that these roles occur. Science must go to the next level in which research is subjected to the rigors of pharmaceutical cause-and-effect relationships of double-blind placebo studies with validated markers and validated outcomes.
To validate the probiotic concept, the molecular mechanisms and active components responsible for these organisms' benefits must be defined.3 Clinical studies should be performed that relate specific bacterial characteristics with the physiological or health-based outcome. This means making comparisons between a probiotic culture, with a particular property (e.g., adhesion), and its variant, deficient in that property (e.g., no adhesion), to determine its functionality in the GI tract (e.g., colonization potential).
The continual development and commercial introduction of new probiotic strains present new challenges to the scientific community. Thus, the question arises as to "who's who" in these new cultures and what is their molecular taxonomy. For example, what we use to think of as Lactobacillus acidophilus is now known to be a mix of six different species. One is still considered Lactobacillus acidophilus but others include L. johnsonii and L. gasseri, which are commonly found in humans and are considered to evoke "acidophilus-like" probiotic properties.
In one study, we examined 20 consumer products claiming to contain L. acidophilus and sequenced their 16S DNA gene to make a true identification. Only eight contained the organism they claimed. Others included organisms such as L. gallinarum or delbrueckii or Pediococcus pentosaceus. Bottom line, no product should be on the market today that doesn't have what it claims.
On a positive note, when the eight acidophilus cultures were fingerprinted, all had very similar genetic content. This means that as good scientific information is developed, it should positively impact everyone selling products with L. acidophilus.
Advances in genetic research allow us to study intestinal flora in vivo (in the body) like never before. The DNA from microorganisms in fecal material can be isolated, amplified, and fingerprinted. Using these fingerprints, we can identify the bacteria present and monitor the changes in this microflora after changing a diet or adding a probiotic culture.
The future of probiotics may include the novel uses of these organisms. For example, we know that some probiotic cultures can adhere to mucosal intestinal cells and that close interaction promotes stimulation of the immune system. As this relationship is better understood, it is likely that probiotic strains will be developed to move beyond their current role as immune-enhancers to be delivery vehicles for bioactive compounds, such as vaccines, enzymes, antimicrobials, and bioactive peptides.
On the Web: PROBIOTICS
- See the site on articles on emerging and antibiotic resistant pathogens
Center for Disease Control information on emerging diseases
Article reviewing Ewald's theory on diseases and microbes
More on Ewald's theory and the potential for plagues
- See the site on National Digestive Disease information on ulcers