Probiotics: Our Friends on the Inside, Part I
Volume 18 Issue 27 2010-07-09
Move over, E.coli, listeria, and salmonella. We’re talking friendly bacteria here. Specifically, we’re talking about those good, or probiotic, bacteria that reside in the human digestive and vaginal tracts.
What are these micro-organisms? The word probiotic means “for life”; in other words, they are important for human life and health. And in the light of the positive scientific research pouring in, you’d have to concur that these bacteria were suitably named.
What, when, and where?
For centuries, we’ve known that milk transformed into yogurt or other substances (like kefir) through lactic acid fermentation. But it wasn’t until the 20th century that the exact reason for this became known: probiotic bacteria were responsible. Metchnikoff, the Russian scientist behind this discovery, determined that the probiotic bacteria involved in the milk-to-yogurt transformation actually “seeded” the intestines with beneficial bacteria. This seeding, he said, caused the positive health effects resulting from consumption of fermented milk products.
He wasn’t too far from the truth.
The deep, dark secret
In the average person’s digestive system, there are approximately five hundred different types, or species, of micro-organisms that colonize there. (Nice thought.) As you’d expect, some of these micro-organisms, like probiotics, are peaceful; others, like Candida (yeast), are not. For intestinal health, you need to have a higher percentage of the good probiotic bacteria than yeast, fungi, or other unpleasant micro-organisms. Why? Because having an overabundance of good bacteria means that the good squeeze out the bad. It’s like musical chairs: if the probiotics have most of the seats, the harmful organisms have nowhere to live.
In addition, an abundance of probiotic bacteria in the intestines has many scientifically validated advantages. For example, it helps those with irritable bowel syndrome; prevents ulcers; reduces allergies; prevents traveller’s diarrhea and chronic diarrhea; improves immunity; and promotes superior absorption of trace minerals, including co-production of vitamin K (a vitamin necessary for blood clotting).
But for many of us, if the good bacteria aren’t outnumbering the bad, we suffer from some (or all) of the following symptoms: gas, bloating, headaches, poor bowel function (including irritable bowel syndrome), fatigue, yeast infections, skin disorders, and allergies, to name a few.
What are their names?
The word probiotic is a general term, similar to how we describe ourselves as human beings. But there are many types, which live in different areas of our bodies and perform different functions. Probably the best known, and best studied, probiotic is Lactobacillus acidophilus, often nicknamed “acidophilus”. L. acidophilus is a primary resident in the small intestine (the first part of your intestine; it attaches to your stomach).
Also common are the Bifidobacteria, which love the climate of the large intestine. They are also one of the main probiotics that pass through human breast milk to a nursing baby, conferring probiotic protection on the baby. Other probiotics include Lactobacillus rhamnosus (often found in the vaginal tract, helping to prevent vaginal infections), Lactobacillus reuteri (ulcers, beware), and Saccharomyces boulardii (protects against traveller's diarrhea).
So what do I ...
The good news is that if you do lack enough probiotic bacteria, they are easy to incorporate into your diet. Grandma always said that yogurt was good for you, and she really was right. Other fermented foods, like kefir, fresh sauerkraut (not in the cans or jars, since these have been heat-treated), miso, and tempeh, also often carry certain probiotic strains from the fermentation process. The goal is one to two servings a day of a fermented food to help maintain a healthy digestive system.
However, there’s a catch. Yogurt and fermented foods may do the trick for you and help you maintain your health, but if you already have a digestive disorder, the good bacteria strength in fermented foods just isn’t enough. You’ve got to flood the good bacteria back into you in order to change things around.
For instance, if you have dysbiosis (gas and bloating following meals), the bad bacteria outcompete the good probiotics. Just eating yogurt (including the so-called probiotic yogurt) won’t give you the chance to overcome this. Could you expect your car to drive halfway across Canada without sufficient gas? In the same way, a couple servings of yogurt won't give your body enough fuel to drive the good bacteria into action to overtake the bad.
In the next instalment of “Health Matters,” we’ll explore how many probiotics to take to counteract digestive disorders. We’ll also investigate some funny quirks of these bacteria, and discuss cautions, including whether they should be used while taking antibiotics.
Katie D’Souza is an AU graduate and a licensed naturopathic doctor. She currently lives in Ontario.
The information contained in this article is for personal interest only; it is not intended for diagnosis or treatment of any condition. Readers are always encouraged to seek the professional advice of a licensed physician or qualified health care practitioner for personal health or medical conditions.
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