There are more than 400 different species of bacteria in the human digestive tract. The most important of these are Lactobacillus acidophilus and Bifidobacterium bifidum. They are called probiotics, the opposite of antibiotics, because they aid in creating a healthy balance of microflora in the gut. The primary use of probiotics is to restore the normal flora in the intestines that often occurs because of poor diet or the use of antibiotics. They do this first by competing with other organisms for nutrients. They secrete lactic acid and acetic acid that decrease the pH of the vagina and intestines, making the environment less favorable for the pathogenic bacteria to thrive. Antibiotics can alter the bacteria in the gastrointestinal tract, decreasing the numbers of healthy bacteria and causing diarrhea. Probiotics, taken during or after antibiotic therapy, can reduce or prevent this effect.

Probiotics produce certain antimicrobial compounds that kill some of the undesirable pathogens in the intestines, including yeasts, virii and bacteria. The associated decrease in the production of potentially cancer-causing toxins by the unfavorable microorganisms may help decrease the incidence of colon cancer. Probiotics also make certain vitamins needed by the body including folic acid, vitamin B6, niacin and vitamin K.

When large doses of probiotics are first taken, mild gastrointestinal symptoms may occur and flu-like symptoms may also occur within 3 days. Low counts of Lactobacillus and Bifidobacterium, with an increase in less desirable bacteria in the intestines can cause gas, diarrhea, constipation, mucosal irritation and contribute to the development of allergies. As the number of undesirable bacteria increases, the absorption of certain nutrients, including the B vitamins, decreases, leading to the possibility of deficiencies. Symptoms of toxicity from taking probiotics are rare.

If supplementation is needed, start by taking at least 1-10 billion viable L. acidophilus or B. bifidum cells daily divided into 3 or 4 doses. Take them on an empty stomach or at least 30-60 minutes before eating. Take 15-20 billion viable organisms daily to prevent diarrhea from antibiotic therapy. Generally you should use products that contain a mixture of live organisms and have an expiration date on the label. Extreme heat or freezing can kill the live cells. Food sources of probiotics include yogurt and milk with live cultures.

Problems with Lactobacillus administration include the failure of organisms to adhere to the intestinal mucosa or to survive damage from gastric acid and bile. The acidophilus sweepstakes has led to the search for newer and better strains for medical uses.

Supplements of fructooligosaacharrides (FOS) promote the growth of Bifidobacteria. Bifidobacteria use the fiber from foods such as fruits, vegetables, legumes and grains to make short-chain fatty acids, including butyrate. Butyrate is an important source of energy for the cells lining the colon and promote a healthy colon. The recommended dose of FOS is 2-3gm per day. Foods containing fructooligosaacharrides include onions, asparagus, garlic and Jerusalem artichokes.

Many years ago, food preservation was accomplished through lacto-fermentation, a process that adds a host of beneficial microorganisms to food, making them easier to digest and increasing the healthy flora in our intestinal tracts. Because fermentation is an inconsistent process, commercial food processors developed techniques like pasteurization (which kills all microorganisms) to help standardize more consistent yields.

Sadly, modern culture has sacrificed many of the advantages of traditionally fermented healthy foods for faster and cheaper methods of mass production. Increases in viruses, intestinal parasites and chronic health problems are warning signs that it’s time to return to the use of traditionally fermented foods.

The living cultured foods commercially available include some brands of kefir, yogurt, miso, sauerkraut and a pickled Chinese cabbage called kimchee.