You have certainly heard by this time that probiotics are our friends and good to have populating our guts. You likely have also heard that antibiotics kill these beneficial microbes which then need to be replaced—usually by taking some very expensive capsules. This may or may not be completely effective and the fault is not with the capsules. What ‘they’ generally fail to tell you is that you also need to support your beneficial microbes (the contents of those expensive capsules) with their preferred food. Yeah, you have to feed your microbes the right food. We call the food of probiotics ‘pre-biotics’. To understand why the right food matters when trying to reestablish beneficial microbes it helps to understand how microbes compete for real estate there:

  1. Use of nutrients: those who can make use of available nutrients flourish. A diet high in fiber (a prebiotic) benefits probiotics. A diet high in sugar benefits harmful microbes including yeasts.
  2. Access to intestinal cells: if they can stick to the cells of the intestines, they get to stay around longer. In other words, "location, location, location" the mantra of real estate both externally and internally.
  3. Production of antimicrobial chemicals: some bacteria produce their own antibiotics (chemicals that inhibit growth of other bacteria). Their by-products of digestion can also act in adverse ways against their competitors. For example: probiotics digest fiber whose digestive by-product is acids similar to vinegar--and yeasts don't like an acidic environment.

 So, as points 1 and 3 indicate, foods high in fiber encourage probiotics to take up residence while foods high in sugar help harmful yeasts take up residence. What you eat determines which microbes choose to reside within and help—or harm—you health. More evidence that we are indeed what we eat!

As stated, prebiotics are the foods upon which probiotics live. Essentially, they live in symbiotic harmony with their host by living off the parts of the foods the host is unable to digest. In so doing, they provide ‘waste products' such as the vitamins B12 and K. Fiber is the main food source for beneficial bacteria.

 Probiotic top ten list of favorite Prebiotics are:

  1. Fruits / Vegetables--including the skins
  2. Trail Mix: prebiotic convenience food
  3. dark berry juices
  4. Herbs and spices (source of phenols)
  5. Whole Grain Sourdough Bread
  6. Oats
  7. Legumes
  8. Tea
  9. Red Wine
  10. Dark Chocolate and Cocoa Powder

Along with the probiotics themselves and their prebiotics (their food), there is a third element: metabiotics--the metabolic by-products of probiotics. The most important of these metabiotics are Short-Chain Fatty Acids (SCFAs). If you heat foods containing probiotics, the probiotics die. Dead probiotics can not populate the internal environment. But, metabiotics remain after heating and are still beneficial in promoting a healthy digestive tract. They do so by:

  1. creating an environment most favorable to probiotics -- Candida albicans and other yeasts can not grow well in the presence of SCFAs.
  2. they nourish the cells of the lining of the colon, promoting the integrity of the intestinal wall.
  3. they signal the immune system to limit inflammatory responses both in the gut and through influencing T-cells throughout the body.

Food sources of probiotics and their metabiotics are:

  1. yogurt
  2. kefir
  3. aged cheeses (aged more then 6 months)
  4. fermented foods such as pickles, saurkraut, kimchi, sourdough bread, miso, etc.
  5. kombucha

Unless you are fermenting at home: be aware there is a difference between fermented pickles and sauerkraut and the vinegar processed versions most commonly sold in stores. Your whole-foods store or co-op may have access to raw sauerkraut and fermented pickles. Asian markets are good places to find kimchi and other fermented foods. Kombucha is a fermented tea beverage which contains from nine or perhaps more varieties of probiotics. You can find it bottled in stores (G.T. Daves or Synergy) or you can brew it at home.