Probiotics: The good bacteria

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Probiotics contain beneficial or “good” bacteria. These “good” bacteria are normally found in the body and exist in the digestive tract, (stomach, small intestine and large intestine), to aid in our digestion. They also compete with and inhibit harmful, disease-causing bacteria, helping to maintain a proper micro-organic balance in your intestinal tract.

Friendly bacteria are important from the moment of birth on. A newborn baby has essentially no digestive bacteria but within a few hours bacteria and microbes begin to colonize in the digestive tract. L. acidophilus in the mother’s vagina inoculates the newborn as he/she passes through the birth canal and provides protection from other bacteria as well as assisting with the baby’s digestion and production of vitamins. The Bifidobacteria are concentrated in breast milk and passed onto the nursing newborn, greatly decreasing the possibility of serious infection during infancy. In this way, human beings usually start life with a relatively balanced and healthy intestinal tract.

A decrease in levels of good bacteria in our systems over time can be caused by medications, poor diet, stress or intestinal infections. Antibiotics kill bacteria, both the bad and the good. High-dose antibiotics or multiple courses of antibiotics can result in low levels of good bacteria. This sometimes results in the development of diarrhea while taking antibiotics. The use of probiotics to reduce or eliminate diarrhea during or after taking antibiotics is scientifically supported and some pediatricians are now making the recommendation of probiotic supplements when writing prescriptions for antibiotics.

There is also some evidence to show that probiotics are beneficial in reducing the severity of eczema in infants and young children. The Mayo Clinic recently gave probiotics a green light rating and stated that there are studies supporting the potential for probiotics to have a positive effect on general health. Specifically, a reduction in severity of a cold or flu, diarrhea (including traveller’s diarrhea) and eczema.

Probiotics can be a beneficial addition to a healthy diet in both children and adults and does not have to be expensive or difficult. Homemade yogurt is a terrific option and can be mixed with fresh fruit or honey for a great taste. For treatment of specific health concerns, supplements are a better, short-term option and a visit to your naturopath or physician can provide guidance.

Read the label

If the product contains probiotics, look for these key features on the packaging so you know what you’re getting.


Probiotic strains are classified as either resident or transit. Resident strains are those commonly found in the human digestive tract and bacteria from supplements containing these strains are able to re-establish in the intestinal tract. Transit strains pass through the system and do not re-establish themselves. Certain transit strains do have strong abilities to fight infection. Look for multiple species from either the Lactobacillus or Bifidobacteria family including both resident and transit strains.

Expiration date

In order to be beneficial, the bacteria have to be LIVE cultures. An expiration date is helpful since many probiotic species are affected by time, heat and oxygen, and it’s important that the live cell count at the time you use the probiotic is equal to what is stated on the package. The more processed the food is, the more difficult it is to keep cultures viable. The best quality probiotic supplements need refrigeration to keep the bacteria cultures viable.

Serving dosage

Probiotics are measured in billions per serving or dosage. A minimum of two billion live bacteria is recommended to maintain good bacteria levels in the digestive tract. This dosage can be consumed daily from foods such as yogurt, cheese, miso, tempeh and some soy beverages. High quality sources of these foods are good options for supporting good digestion and  health. For specific situations such as post-antibiotic use, treatment of diarrhea or eczema, the minimum dosage is 10 billion live bacteria. The best source for this higher dosage is in supplement form. Powder form is most stable, must be kept refrigerated and is easily mixed into food and/or drinks. This level of probiotic is also available in suppository, capsule or tablet form. There are also probiotic drinks available at specialty drug stores or health food stores.

Originally published in ParentsCanada magazine, March 2011.

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