What are probiotics?

Probiotics are live bacteria and yeasts that are called the “good” microorganisms because they benefit the body, specifically the digestive system, by helping digest food, destroying disease-causing microorganisms, and producing vitamins. Probiotics available in some foods and dietary supplements are similar to the probiotics that exist naturally in your gut.

What do probiotics do?

The body does not need the addition of food and supplements that contain probiotics to be healthy. However, food and supplements that contain probiotics assist the job of the "good" bacteria that are already present in your gut. Probiotics may help keep you healthy by:

  • Decreasing the number of "bad" bacteria in your gut that can cause infections or inflammation (swelling).
  • Stabilizing the digestive tract’s barriers against “bad” bacteria, or producing substances that hinder their growth.
  • Replacing the body's "good" bacteria that have been lost, for example, when you take antibiotics.
  • Restoring the body's "good" versus "bad" bacterial balance, which then helps to keep your body functioning properly.

What are some examples of probiotics?

  • Probiotics that are naturally found in your intestines include: Saccharomyces boulardii (a yeast) and bacteria in the Lactobacillus and Bifobacterium families of microorganisms. (Outside of the body, Lactobacillus acidophilus is the probiotic that is found in some yogurts.)
  • Foods that contain probiotics include: some juices and soy drinks; fermented and unfermented milk; buttermilk; some soft cheeses; miso; tempeh; kefir; kimchi; sauerkraut; many pickles; and yogurt (probably the most well-known food product that contains probiotics).
  • Supplements: Dietary probiotic supplements -- which are available in capsules, tablets, powders and liquid extracts -- each contain a specific type of probiotic. These products are available at health food and natural food stores, vitamin shops, and other stores. As an example, one commonly used supplement is Acidophilus, which is available from several supplement manufacturers.

What medical conditions are probiotics used for?

Probiotic supplements may be useful in treating and preventing inflammatory digestive tract conditions such as pouchitis (which affects people who have had their colons removed), inflammatory bowel diseases (such as ulcerative colitis and Crohn's disease), and chronic (long-term) stomach inflammation and ulcers caused by the Helicobacter pylori bacterium.

Probiotics may also be helpful in treating constipation, irritable bowel syndrome, acid reflux, and spastic colon; shortening the duration of infectious diarrhea; and reducing the recurrence (return) of bladder and colorectal cancer. Probiotics are also being studied as a method of boosting the immune system

Some studies suggest that yogurt is helpful in preventing diarrhea (a common side effect of treatment with antibiotics). It has also been shown to prevent or treat urinary tract infections and vaginal yeast infections in women.

Other conditions and situations for which probiotics are being studied include:

How safe and effective are probiotics?

Because probiotics already exist naturally in the body, probiotic foods and supplements are generally considered safe. They may trigger allergic reactions, and may also cause mild stomach upset, diarrhea, or flatulence (passing gas) and bloating for the first few days after starting to take them.

People who have weakened immune systems (on chemotherapy, for example), the critically ill, those who have had surgery, and very sick infants should use probiotics with caution, because infection has been occasionally reported.

In terms of effectiveness, keep in mind that unlike medications, dietary supplements do NOT need to be approved by the FDA. This means that manufacturers can sell supplements simply with "claims" of safety and effectiveness.

At this time, researchers are undecided if probiotic supplements are effective. Some say they are, others believe that they offer no benefit whatsoever. It also remains unclear which probiotics (or combination of probiotics) work to treat certain diseases. Some studies have shown positive results, but more research is needed to confirm that probiotics are safe and effective.

Always talk with your doctor (or pediatrician) before taking a supplement or giving one to your child. Supplements might interfere with medicines you may be taking. If you are pregnant or breast feeding, check with your doctor before taking any supplement.

Do probiotics need to be refrigerated?

Several probiotic strains are very fragile and need to be protected from elements that will slowly reduce their viability, including heat, oxygen, light and humidity (to name a few).

It is important to know whether the probiotic you take should be refrigerated. Most commonly used probiotic bacteria, such as Lactobacillus acidophilus, casei, Bifidobacterium bifidum, adolescentis, breve, longum and Saccharomyces boulardii are some of the most fragile, and are very sensitive to light, heat, moisture and oxygen. These probiotic bacteria strains need to be refrigerated so that they remain viable until they are consumed and the person derives full benefit.

There are strains that do not need to be refrigerated. One is known as Bacillus subtilis, a “soil-based organism” (SBO). This probiotic species has a shell that naturally protects the cell’s core (protecting these cells from acidic environments in the stomach and upper intestines) until it reaches the desired location. These SBO probiotics remain viable regardless of refrigeration and without the need for artificial encapsulations or coatings that other probiotics may require.

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