All About Probiotics

by Ryan Andrews, May 3rd, 2010.

Precision Nutrition

What are probiotics?

Who could forget Élie Metchnikoff? Don’t know him? He’s only considered the inventor of probiotics. He came up with a theory that aging  is caused by toxic bacteria in the gut; to prevent this, he drank sour milk every day. He was born in 1845 and made it to 71, so he may have been on to something.

The term probiotic comes from the Latin or Gree pro, “before, forward”, and bios, or “life” — thus probiotics are life-promoting. In this case, we use the term probiotics to refer to beneficial bacteria.

We have billions of friendly bacteria living in our digestive tract. If you extracted all of the microbes that live in your body, you’d have over a quart of sludge. Each person’s bacterial flora may be as unique as fingerprints.

Friendly bacteria help us digest our food and absorb nutrients effectively. In a sense, we don’t actually digest many components of our food — the bacteria digest it.

The probiotic bacteria used in commercial products today are largely members of the generaLactobacillus and Bifidobacterium.

Check out a food or supplement with probiotics and the label might say something like “Lactobacillus rhamnosus GG.”

The first name that appears is the genus (Lactobacillus).

The second name designates the species within the genus (rhamnosus).

The third name or number that appears is the specific strain within the species (GG).

currant quart All About Probiotics

Why are probiotics so important?

To understand why probiotics are important, we first need to understand how valuable beneficial bacteria are to our health, and how prevalent they are in our bodies.

What do gut bacteria do?

In our gut, good bacteria can displace bad bacteria and influence our overall health, metabolism, digestion, and body composition.

Gut bacteria are involved in immunity and help to ensure our immune system doesn’t have an itchy trigger finger (think food sensitivities).

Gut bacteria also:

  • help synthesize B and K vitamins
  • enhance gastrointestinal motility and function
  • enhance digestion and nutrient absorption
  • obstruct the growth of “bad bacteria” and other pathogens
  • help metabolize other plant compounds/drugs
  • produce short-chain fatty acids (SCFAs) and polyamines
  • produce coagulation and growth factors
  • produce cytokines (cell signaling molecules)
  • help regulate intestinal mucus secretion and ultilization
  • help regulate blood flow to the viscera

Uhmm… how much are in there anyway?

Imagine how many cells you must have making up your body. Zillions, right? Well, imagine 10 times that. That’s how many bacteria we have.

Our internal bacterial environment is very lively and complex. Scientists estimate that we have over 50 genera of bacteria that provide over 500 different species! There’s a party in our tummies!

Some researchers even suggest that our bacteria are like an entirely distinct organ — a “microbe organ” that is nearly as big and important (if not more so) than the liver.

good bad bacteria All About Probiotics

Thus, given the extent of bacteria’s roles, and the importance of these good bacteria to proper physical functioning, it’s important for us to help keep a healthy bacterial environment.

Probiotics can help replenish and nourish this internal supply of good bacteria.

Adequate consumption of probiotics can help to eliminate abdominal pain, gas, bloating, reflux, allergies, nausea, food poisoning and vomiting. Probiotics may even alleviate irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and dermatitis. You guessed it – this means they are anti-inflammatory.

What you should know

What causes intestinal dysbiosis?

While our intestinal bacteria are pretty tough little critters, their health can be compromised. The most common causes of poor gut health are:

  • medication use, especially antibiotics
  • stress (stress hormones may encourage bad bacteria growth)
  • poor diet (e.g. sugar, preservatives, alcohol, processed foods, over-eating, inadequate fibre)
  • aggressive medical therapies such as radiation or chemotherapy
  • over-consumption of animal-based protein, especially highly processed (e.g. luncheon meats)
  • poor gut motility (which can be caused by the above factors)

One important feature of a healthy GI ecosystem is balance. When good bacteria flourish, bad bacteria and other micro-organisms such as yeasts and fungi are pushed out.

And speaking of diet, if you eat animal foods, the gut health of the animal is important too. When animals used for meat/dairy consume pre- and probiotics, they have healthier guts and bodies.

What makes probiotics?

Most often, probiotics are created via fermentation. Friendly bacteria are all around us — you’re soaking in them! — so fermentation simply collects them and gives them a nice place to grow. Fermentation organisms produce alcohol, lactic acid, and acetic acid, preservatives that retain nutrients and prevent spoilage.

Probiotics are found in yogurt, buttermilk, kefir, sauerkraut, kimchi, and bacterially cultured cheese. Traditional methods of meat preservation (such as the curing of salami) also use fermentation of Lactobacilli to preserve the food, although arguably industrially produced cured meats no longer have health benefits.

Benefits of fermentation

Fermentation not only bumps up good bacteria but helps eliminate anti-nutrients. When grains, seeds and tubers are soaked, sprouted and/or fermented, we disable anti-nutrients. This is good. It means:

  • The food is more digestible (think tempeh instead of soybeans or yogurt instead of milk)
  • The food has more minerals (thanks to less phytates)
  • The food has more protein (thanks to less protease inhibitors)

And vitamin B12 is a product of bacterial fermentation. So, fermenting can create a reliable form of this nutrient.

Most tea is fermented. Fermentation intensifies the stimulant properties of the leaves and produces black and oolong varieties. Green teas are the unfermented leaves of Camellia sinesnsis.

As with all products containing living bacteria, probiotic products must be cooled during storage. If heated, they won’t survive. This includes pasteurization.


Prebiotics help keep probiotics alive. We don’t digest prebiotics, which come mainly from oligosaccharides (complex starches), but probiotics love them.

Inulin and fructo-oligosaccharides (FOS) are common prebiotics. You’ll get them from legumes, fruits and whole grains. They are abundant in the food supply (assuming you eat real food). Oh, another prebiotic is galacto-oligosaccharide (GOS), found in human breast milk. Hooray for breastfeeding.

merchandizer 64893 154x300 All About Probiotics

An example of a prebiotic supplement

Prebiotics Probiotics
What are they? Inulin
Fructo-oligosaccharides (FOS)
Galacto-oligosaccharide (GOS)
Polyols like lactulose and lactitol
Certain species and strains of:Lactobacilli
Food sources Barley
Honey and agave
Bacteria:Certain yogurts including dairy/coconut/soyKefir including dairy/non-dairyButtermilkSauerkraut (make sure it’s fermented and not just soaked in vinegar)Pickles (make sure they are fermented and not just soaked in vinegar)

Bacterially fermented cheeses


Yeasts, molds, and fungi


Soy sauce



Mould-enhanced cheese (e.g. blue cheese)

Potential benefits May improve GI health and nutrient absorption by nourishing good bacteria May improve GI health and systemic immunity

Summary and recommendations

Probiotics seem to improve overall health, metabolism, immunity, digestion, and body composition. They may even help alleviate inflammatory conditions.

Getting probiotics from food:

  • If you are healthy, aim for 1-2 servings of probiotic rich foods each day (use the food source list above). If you’re hoping to prevent or alleviate a medical problem, you may need to increase the dose.

Getting probiotics from supplements:

  • Supplemental doses are typically expressed in billions of live organisms. Between 3 and 5 billion would be a starting dose. This could be increased to 10 billion if you are hoping to alleviate a specific health concern. Take with food/drink and use a reputable brand.

Getting prebiotics from food:

  • If you are healthy, aim for 2-3 servings of prebiotic rich foods each day (use the food source list above).

Getting prebiotics from supplements:

  • 2-4 grams of FOS per day can help to feed healthy gut bacteria and keep things balanced. Supplementing pre- and probiotics at the same time might be a good idea.

Take note:

You may actually feel worse before you feel better since bacteria release toxins.

Immune-compromised individuals can develop infections from probiotic microbes – be cautious if you are taking immunosuppressive drugs, if you have AIDS, if you are receiving radiation or chemotherapy, and/or if you are in the hospital.

Extra credit

Probiotics are not digestive enzymes. Digestive enzymes are like chemical grinders that chew up substances and break them down for us so we can absorb them. For example, we can’t absorb big chunks of protein, so our body uses proteases — protein-breaking enzymes — to break them down into smaller parts that we can digest.

Even dead probiotics appear to have beneficial effects.

It appears that using probiotics during pregnancy is safe.

Together, all of the microbes in your body weigh about 3 pounds – more than your kidneys.

Side effects of antibiotics include diarrhea, yeast infections and oral thrush.

four bacteria All About Probiotics

Don’t these bacteria look friendly? (From


Keith L. The Vegetarian Myth. Flashpoint Press. 2009.

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Kristen’s Raw

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Ellix Katz S. Wild Fermentation. Chelsea Green Publishing Company. 2003.

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IFIC. Food Insight

Society for General Microbiology (2008, April 4). Prebiotics — The Key To Fewer Food Poisoning Stomach Upsets — And Healthy Farm Animals. ScienceDaily.

Ramakrishna BS. Probiotic-induced changes in the intestinal epithelium: implications in gastrointestinal disease. Trop Gastroenterol 2009;30:76-85.

Dugoua JJ, et al. Probiotic safety in pregnancy: a systematic review and meta-analysis of randomized controlled trials of Lactobacillus, Bifidobacterium, and Saccharomyces spp. J Obstet Gynaecol Can 2009;31:542-552.

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2 thoughts on “All About Probiotics

    • Yes very much so!!
      Green tea is touted as one of the healthiest drinks on the market, with a whole host of health benefits.  But why is it so good for us?

      Health Benefits of Green Tea

      Many health benefits have been associated with regularly drinking green tea.  These include:

      eliminating free radicals within the body
      absorbs and blocks cholesterol
      decreases the levels of cholesterol in the blood and prevents the process of oxidisation creating bad cholesterol
      helps prevent heart related conditions within the body
      works to normalise blood pressure levels
      helps to fight bacteria and viruses
      improves the condition of the intestines by blocking bad bacteria and increasing levels of good bacteria
      helps to detoxify the body
      helps to stabilise diabetes
      can assist in weight loss
      slows the ageing process
      helps to strengthen the immune system
      The Antioxidants in Green Tea
      Green tea is such a powerful drink because of the antioxidants it contains.  The antioxidants that are responsible for most of the health benefits of green tea are called polyphenols and these are considered to be the most effective of all the antioxidants.  Green tea is particularly rich in a subgroup of polyphenols called catechins, containing between fifteen and thirty percent of catechin content. 

      There are four main catechin substances – EC, ECg, EGC, and EGCG, with EGCG or epigallocatechin gallate being the most powerful.  EGCG is an antioxidant that is approximately 25 to 100 times more powerful than vitamin C or vitamin E.  EGCG has been shown to inhibit the growth of cancer cells, kill cancer cells without hurting healthy tissue, lower the levels of bad cholesterol, and also to help stop abnormal blood clots from forming. 
      How Green Tea is Processed

      Green tea is processed differently to other forms of tea.  For green tea, the leaves are steamed immediately after picking before being rolled and dried, and this stops the EGCG compound from being oxidised and lost.  By contrast, black teas are made from tea leaves that are withered by exposure to the air before being fermented, and this causes EGCG to be converted into other, less effective, compounds.
      So keep drinking it!!


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