Beneficial bacteria are considered the most commonly consumed functional foods worldwide. Though not well understood by most modern Americans, foods fermented with beneficial bacteria, such as yogurt, cheese, Kefir, and sauerkraut,
have been a part of our diet since ancient times. Another term for beneficial bacteria is “probiotics.”

According to research, fermented foods were expected to prolong the life span of Europeans as early as the 1800s. Today, numerous scientific studies demonstrate that probiotic bacteria and foods fermented with beneficial organisms have a variety of health benefits.

PROBIOTIC BASICS
There are hundreds of different bacterial species inhabiting the human gut; the composition of which varies from one person to another depending on diet, age, medication, stress levels, andphysiological conditions.

Among the hundreds of bacterial species in the human digestive tract, some are potentially disease-causing, while others—known as probiotics—are friendly. The term probiotics is derived from the Greek word meaning “for life,” which is in direct contrast to the more familiar term “antibiotics.” Though there is no current standard definition, probiotics can be defined as: “Viable organisms in a supplement or food form that exert health effects on the host when consistently ingested.”

Probiotics are found in fermented or fortified foods, and also in supplements. To qualify as probiotics, the organisms must meet the following criteria:

HEALTH EFFECTS OF PROBIOTICS
Friendly probiotic organisms protect the host in many ways. Among its many numerous benefits, probiotics are particularly extraordinary for people who: consume little fiber or fermented foods, take antibiotics, experience repeated intestinal or vaginal infections, or travel frequently. For those who simply want to maintain their well-being or strengthen their intestinal immune system, probiotic products are something to strongly consider.

SAFETY
Probiotics, especially those belonging to Lactobacillus and bifidobacterium genera, have a good safety record. There have been no reported drug-probiotic interactions. However, not all the species have the same influence on the host, and people with different physiological status or conditions will have various responses to organisms. There have been some isolated incidences in which beneficial bacteria have become infectious. Probiotics should not be recommended to people with compromised immune systems or with conditions prone to infections. People with these conditions should consult their physician before taking probiotic supplements or fermented foods.

SELECTING PROBIOTIC SUPPLEMENTS
Probiotic organisms are very sensitive to temperature and moisture. They are usually unstable when not refrigerated or exposed to moisture. Unless a product is specially manufactured with a systematic control procedure, such as strain selection, fermentation medium and environment, drying, encapsulation, and coating, it should be refrigerated. Consumers should question products claiming “no refrigeration needed,” and ask for the documentation from the manufacturer.

Another issue is whether to take a probiotic product with a single strain or mixed strains. Since numerous microorganisms cohabitate in the human intestine and each probiotic strain is unique, there is a trend toward recommending supplementation with mixed strains.

The suggested dose of live bacteria is three to four billion daily, but may vary with a person’s physiological conditions. Probiotics are also available in fermented foods, such as yogurt (especially yogurt with three bacterial strains), acidophilus milk, capsules, tablets, powder, and liquid.

EXAMPLES OF THE POSITIVE EFFECTS AS WELL AS SUPPORTING STUDIES AND CLINICAL TRIALS OF PROBIOTIC USE INCLUDE:

1) REDUCING ANTIBIOTIC-ASSOCIATED INFECTIONS AND DIARRHEA
Millions of antibiotic prescriptions are written annually for treating infection-related conditions. Diarrhea is a common side effect of antibiotic treatment. Antibiotics are broad-spectrum killers that destroy both detrimental and beneficial bacteria residing inside the intestinal tract. Since detrimental bacteria tend to develop a resistance to antibiotics quickly, they can grow uncontrolled, resulting in further infections. Probiotics such as L. acidophilus, B. longum, and Saccharomyces boulardii are very promising in preventing and reducing antibioticassociated diarrhea (AAD) caused by Clostridium difficile, Staphylococcus, Klebsiella, and Candida species. Probiotics suppress the growth and propagation of pathogens. Hence, they reduce the incidence of severe diarrhea.

2) REDUCING THE INCIDENCE AND SEVERITY OF INFECTIONS AND DIARRHEA
In a double-blind, randomized trial with children attending day care, research observed that children who consumed milk fermented with Lactobaciullus (rhamnosus) GG daily had significantly fewer days of absence from day care due to illness. There was also a reduction in the number of children suffering from respiratory infections with complications, as well as a reduction in antibiotic treatments for respiratory infection supplementing with products containing probiotics compared to the control group.

3) MAINTAINING INTESTINAL MICROFLORA BALANCE BY DISPLACING OR DILUTING INTESTINAL PATHOGENIC FLORA BY:
• Directly inhibiting the detrimental bacteria in the intestine by competing for nutrients and residing space
• Creating an unfriendly low-pH environment for detrimental bacteria by producing organic acids, such as lactic, acetic, and propionic acids
• Producing natural antibiotics, such as acidolin, acidophilin, bulgaricin, and plantaricin (bacteriocines) and other substances that inhibit the growth of pathogens

4) DECREASING TOXIC OR CARCINOGENIC METABOLITES AND CANCER RISK VIA THESE MECHANISMS:
• Enhancing natural killer cytotoxicity
• CD8 positive T lymphocytes
• Degrading potential carcinogens

5) MODULATE IMMUNE RESPONSE
Probiotic bacteria modulates the host defense mechanisms by affecting both non-specific and modulating gut-associated immune function. More and more studies show that there is a correlative or suggestive link between immune modulation and enhanced protection by probiotic bacteria.

6) ALLEVIATING LACTOSE INTOLERANCE
The inadequate amounts of the lactose-digesting enzyme beta-galactosidase in the intestinal tract can cause diarrhea, abdominal cramping, bloating, and other discomforts. This condition is known as “lactose intolerance” or “lactose maldigestion.” Fermented milk products, such as yogurt, can improve lactose digestion. Heat-treated yogurt tends to be less effective than fresh yogurt. In addition, fermented foods with probiotic bacteria tend to be more effective than probiotic supplements alone.

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ABOUT THE AUTHOR
Peilin Guo, M.S., R.D., is the Vice President of Functional Foods, Clinical Research, and Asian Market Development for Jarrow Formulas, headquartered in
Los Angeles, CA. She has developed a variety of nutritional and dietary supplements and holds a U.S. patent on a product for improving intestinal health.