Probiotics and Prebiotics
Probiotics and Prebiotics
Gabe Mirkin, M.D.
There are two absorption systems in your body. Food that is easily
broken down is absorbed into your upper intestinal tract. If you
cannot absorb a particular food, it goes to the lower intestinal
tract (colon), where bacteria in your colon ferment it to smaller
products that can be absorbed.
Your colon is loaded with good and bad bacteria. Bad bacteria such
as clostridia that are kept in check by good bacteria. If you take
an antibiotic that knocks off the good bacteria, the clostridia can
overgrow and cause diarrhea.
The good bacteria break down soluble fiber to form chemicals such as
short chain fatty acids that are absorbed into your bloodstream and
travel to your liver where they block the liver from making
cholesterol and help to prevent heart attacks. These short chain
fatty acids also reduce inflammation, so they help to control the
bloody diarrhea and ulcers caused by Crohn's disease. They also
reduce swelling and pain of arthritis, diabetes and psoriasis, and
some studies show they may even improve your immunity to help you to
If you wish to encourage the growth of good bacteria in your colon,
you have two choices: probiotics or prebiotics. Probiotics are
living microorganisms, the good bacteria, that live in the colon and
reduce inflammation and help prevent and treat Crohn's disease,
psoriasis, arthritis, and perhaps even certain types of cancers.
Prebiotics are nondigestible food ingredients that cannot be
absorbed in the upper intestinal tract and travel to the colon where
they serve as a medium to encourage the growth of the good bacteria.
Live-culture yogurt is a readily available source of good bacteria.
However, the lactobacilli that are in live cultures of yogurt will
not colonize in your intestines, so they disappear if you stop
eating yogurt every day. Most yogurt products do not contain live
cultures; read the labels carefully.
One strain of good bacteria that has been studied extensively and
has been shown in controlled scientific studies to have the ability
to colonize in the intestines is called lactobacillus GG. It was
isolated from intestines of humans by two professors at Tufts
Medical School named Sheldon Gorbash and his colleague named Golden,
hence the name lactobacillus GG. They have patented their product
and make a lot of money from it.
Several studies show that Lactobacillus GG can help control the
frequency and severity of infectious diarrhea in children. Diarrhea
that is often caused by taking antibiotics can be prevented by
taking either Lactobacillus GG or Saccharomyces boulardii with the
antibiotics. A probiotic preparation (VSL=3 - 6 g/day) that uses a
combination of three species of Bifidobacterium, four strains of
Lactobacillus and one strain of Streptocccus has been shown to
maintain remission in ulcerative colitis as well as in preventing
the postoperative recurrence of Crohn's disease. Taking probiotic
compounds is well tolerated and safe.
Prebiotics are found in certain foods that are not completely
absorbed in your upper intestinal tract pass to your colon and form
the food that encourages growth of the good bacteria. Soluble fiber
is the part of these foods that is most likely to encourage the
growth of good bacteria. Prebiotic supplements are available, but it
is easier and cheaper just to eat plenty of the foods that provide
this benefit. Good sources of soluble fiber are whole grains, beans,
seeds, vegetables and nuts.
The use of probiotics in gastrointestinal disease. Canadian Journal
of Gastroenterology, 2001, Vol 15, Iss 12, pp 817-822. KL Madsen.
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