The human body is a walking ecosystem. Although we do not usually think
of ourselves in this way, the fact is that we are “home” to trillions
of microorganisms that live on and inside us. We are actually made up of
90% bacteria cells (100 trillion) and only 10% animal cells (10 trillion).
Every person harbors more microorganisms in their gastrointestinal tract
than there are people in the world, or have been in all of history. The
gums, teeth, hair, and skin are also richly populated with many types of
Although some of the microorganisms inside us may be harmful, the vast majority
are not. In fact, they are necessary for good health. Human beings have
evolved with these microorganisms, and we have developed a symbiotic relationship
with them. For instance, beneficial bacteria in the intestines help digest
foods, create vitamins (such as B-12 and K), and inhibit the growth of disease-promoting
pathogenic bacteria. Without these beneficial or probiotic microorganisms,
as they have now come to be called, we could not survive.
Throughout history many peoples have traditionally eaten certain cultured
and fermented foods that are rich in beneficial microorganisms and can increase
digestive strength and general health. For instance, fermentation with lactic-acid
forming bacteria, including Lactobacillus acidophilus, is one of
the oldest methods of making cultured foods such as yogurt and sauerkraut.
In ancient days, this process was inadvertently initiated in milk and vegetables
using the organisms naturally present in the raw food, the air, or on utensils.
Today, genetically-selected starter cultures are used commercially, and
the industry for foods and supplements that contain probiotic organisms
is rapidly growing. Many scientific studies over the last 50 years have
shown that probiotic organisms can improve the nutritional quality of foods,
as well as produce antibiotics, anticarcinogens, anticholesteremic substances,
and substances that break down and recycle toxins for their human host.
In keeping with the analogy of the body as an ecosystem in itself, the rich
supply of microorganisms in the intestines have been given a special name:
the intestinal microflora, or IM as I will call it for short. The
IM is an amazingly complex mixture, containing an estimated 400-500 different
species of bacteria (at least 17 families and 50 different genera of bacteria).
Among these many species, there may be dozens, or even hundreds, of different
genetic variants or biotypes. All areas of the gastrointestinal tract contain
bacteria, but the colon is by far the most heavily populated. The upper
small intestine is mostly sterile, but the lower small intestine and stomach
have limited numbers of various species of microorganisms, depending on
conditions there. The mouth and vagina also harbor a rich microflora, which
probably plays a role in the health of these areas of the body, too.
Why are there so many different species and biotypes of microorganisms in
the intestines? Well, if you think of the IM as a very basic physical link
between our bodies and the external environment, it begins to make sense.
The purpose of the diversity of the IM is to be able to adapt to the great
diversity of environments that our bodies may come into contact with. **Studies
show that the predominant species or biotypes of bacteria in the IM are
constantly changing. The IM is a swarming, evolving world of bacteria that
is continually responding to changes in diet, climate, microorganisms in
the environment, and other factors that have yet to be determined. Thus,
if we are forced through necessity or climate to subsist on a certain kind
of food that we cannot digest very well, then the make-up of the microflora
will change so that it can produce the enzymes needed to help us extract
the nutrients we need from that food.
For example, most people in the United States would not do well eating large
quantities of lichens. However, the Laplanders from Scandinavia are known
to eat certain lichens, and can gain nourishment from them. Similarly, if
you eat a great deal of meat, or if you eat a high-cellulose diet, your
IM will adapt accordingly. So you can see that the IM must be considered
a very important homeostatic mechanism in the body, helping us to survive
and even thrive in varying environmental conditions.
Benefits of Probiotic Organisms
There are two ways to approach the subject of the probiotic organisms that
constitute the IM. One way is to look at the positive roles that
these organisms play in the body. The other is to study factors that negatively
affect or harm them. To start on a positive note, let’s look first at the
benefits of having abundant probiotic organisms in the body.
Below I have gathered information on eight main points of interest. These
are the major benefits of adding probiotic organisms to the diet, whether
in a pure form such as L. acidophilus supplements, or in the form
of traditional fermented and cultured foods.
Please note that some of the benefits discussed below have been definitively
established, while others seem likely but have yet to be proven beyond a
shadow of a doubt. In particular, certain benefits, such as lowered risk
of irritable bowel syndromes or a cancer-protective effect, have been suggested
by laboratory and clinical tests in Europe and Japan, but have yet to be
verified by thorough double-blind studies in both animals and humans. Some
of the needed research is already under way, while some of it still waits
to be done.
The Benefits of Maintaining a Healthy Indigenous Microflora or Probiotic
1. Boosting the Immune System
2. Inhibiting the Growth of Pathogenic Organisms
3. Prevention of Diarrhea from Various Causes
4. Cancer Prevention
5. Reduced Risk of Inflammatory Bowel Disease
6. Improved Digestion of Proteins and Fats
7. Vitamin Synthesis
8. Detoxification and Protection from Toxins
Microflora Formation in Infants
The formation of the IM begins at birth. As the infant passes through the
birth canal, she or he is “inoculated” with microflora from the
mother’s vagina (Midtvedt, et al, 1988). Later, breast-feeding provides
bacterial and immugenic substances that create a simple flora of Bifidobacteria,
a genus of beneficial lactic-acid producing bacteria especially common in
infants and babies, such as B. bifidum, B. infantis and B.
longum, and a few other beneficial anaerobic bacteria. This early IM
influences the development and composition of the final, adult IM. Significantly,
studies show that a formula diet can allow potentially pathogenic bacteria,
such as clostridia and anaerobic streptococci, to proliferate in an infant’s
digestive tract. It has also been found that the addition of cow’s milk
to an infant’s diet can have negative effects in that it can decrease the
numbers of Bifidobacteria in the intestines and increase the pH and
numbers of bacteroides, which are sometimes considered to be a less (Drasar,
et al, 1986). Thus, once again, so-called “improvements” over
breast-feeding may not, in fact, be improvements at all!
End of sidebar
Negative Side Effects of Antibiotics
There is no question that antibiotics are invaluable medicines. In emergency
situations–such as in the case of a child on the verge of death from meningitis–antibiotics
are literally life-savers. Even in many less extreme situations, they can
be extremely valuable. Nonetheless, antibiotics are too often overused in
current medical practice–with marked negative side effects, one of the
greatest being damage to the intestinal microflora.
The effects of a weakened IM, for reasons explained previously, can be quite
detrimental. Once probiotic organisms have been destabilized and stripped
off the walls of the intestines, potentially pathogenic organisms such as
Candida albicans, Staphylococci, and Clostridium difficile
have much more opportunity to proliferate. This can lead to infection, sepsis,
diarrhea, and colitis (Hill, 95). Significantly, these conditions usually
coincide with a reduction in the number of L. acidophilus in the
intestines (Lidbeck, et al., 1988).
The conclusion one should draw from the research cited is not that antibiotics
should be discarded, but that their use should be minimized. Also, when
their use is essential, it is best at least to combine them with probiotic
supplements to maintain the IM. Below I explain five simple steps to take
to reduce the risk of side effects from antibiotics.
Ways to Minimize the Side Effects of Antibiotics
1. Avoid unnecessary use of any antibiotic.
2. Use antibiotics for as short a period as possible.
3. Use narrow-spectrum rather than broad-spectrum antibiotics.
4. Always take probiotic microflora supplements.
Many of these, including ones containing Lactobacillus spp., have
been shown in studies to minimize the unwanted side effects of antibiotic
therapy, such as diarrhea (after Hooker and DiPiro, 1988).
Commonly Asked Questions About Probiotic Supplements
Now that you are more familiar with the benefits of probiotic supplements,
you may be interested in trying one of the commercial products which are
available in most natural food stores. The following information on commercial
products came from a number of sources including a review of the available
scientific literature, my own personal experience, and from a conference
on Probiotics sponsored by the National Nutritional Food Association (NNFA).
This conference brought together some of the acknowledged experts in the
field, including Dr. K.M. Shahani, probably one of the world’s leading authorities
Why bother to take a probiotic supplement at all? Remember that besides
antibiotics, a number of common environmental influences can strongly affect
our resident microflora, including
- Chlorine and other bacteriocidal chemicals which are often added to
city drinking water
- Chicken and other commercial meats will likely contain residues of antibiotics
added during their growth in pens and other unhealthy living quarters
- Pesticide and herbicide residues may be present in various fruits and
- Excessive sugar, fat, red meat and refined foods in the diet may promote
undesirable species in the IM
Raw vegetables contain natural compounds which may inhibit the implantation
- Alcoholic beverages inhibit the implantation of probiotics
Today, a wide variety of probiotic supplements are available in several
- Powder–introducing measuring devices (spoons, etc.) into the powder
may lead to contamination; more susceptible to moisture and oxygen than
capsules and tablets
- Capsules–may be the most desirable way of taking probiotic supplements;
more protected from contamination, oxygen, and moisture
- Tablets–protected from contamination, moisture, and oxygen better than
powder, but the heat produced during the tableting process may damage organisms
- Liquid–studies show that many liquid supplements are weak, and some
contain few, if any, organisms; if fresh and of good quality, they can be
useful for douching and gargling and are more pleasant to take than capsules
or tablets for some people; an alternative: try opening a capsule or two
and mixing it in distilled water for a more potent liquid dose
- Dairy products that contain added organisms–dairy products containing
lactobacillus and other probiotic organisms provide a mild dose of probiotics
and perhaps help lactose-intolerant people digest it.
When evaluating a probiotic product, questions such as what kind of product
is best, how long to take it, when to take it, do the organisms really implant
in the colon, and what benefits they have are often asked. Although the
experts don’t always agree on these points, there is enough agreement to
offer the following answers, probably the best information on the subject
available at this time.
Commonly-Asked Questions about Probiotic Products
(Taken from the scientific literature, my own experience, and mostly from
the NNFA Probiotics Conference.)
When should I take the product? Before meals? Between meals?
Most experts feel that first thing in the morning on an empty stomach
(when stomach acid is at its lowest levels) or just after meals, when the
food can buffer the acid.
How much is best to take?
For therapeutic benefits, about 4-10 billion viable organisms/day is
What species are best? Is a mixed-species product better or a single
species (like Lactobacillus acidophilus)
The main species used in probiotic supplements are L. acidophilus,
L rhamnosus, L. bifidus, L. casei, L. plantarum,
Bifidobacterium bifidum, Streptococcus faecium, and others (Sandine,
et al 1972, Speck 1976).
This is a controversial question, and not easy to answer. Some experts (like
Dr. Shahani) feel that Streptococcus faecium is an excellent probiotic
species and can be taken alone, or with other microorganisms. Some feel
that only Lactobacillus acidophilus and bifidobacterium should
be used. My experience tells me that because traditional fermented foods
contain a variety of organisms, a mixed species supplement is best. On the
other hand, many people get excellent results from single species products.
My suggestion is to try both kinds and see what results you get–ultimately,
you are the best judge.
Can I trust the product to deliver what it says on the label?
Tests show that there are some excellent products on the store shelves,
and some poor-quality products. Experience and talking with owners or supplement
staff in natural foods stores will usually provide helpful guidance. Above
all, don’t be afraid to ask questions about any companies products. They
should be able to provide tests and hard facts about the species that they
have, the potency, when it was manufactured and so forth. I will also suggest
that you don’t buy any product unless it has the manufacture date right
on the bottle. All of these products, especially lactobacillus and bifidobacterium,
lose a lot of potency after 4-10 months.
Should the product be refrigerated? Some products say yes, some no.
Products last longer when they are refrigerated. Many of the experts
I have heart on the subject say that the best products are ones that are
refrigerated. Only species like Streptococcus faecium does not need
Indications for Probiotic Supplements
1. Maintaining the Probiotic Flora during antibiotic treatment
Begin taking immediately, take up to 2x recommended dose during antibiotic
therapy, then follow product label.
Long-term use can help promote regularity.
Short-term or long-term use can help prevent diarrhea.
4. During pregnancy
Probiotic supplementation during pregnancy can promote regularity and support
nutrition during this important time. A probiotic supplement during breast
feeding may also be helpful.
5. Programs for infants and young children
Supplementation with bifidobacteria may help support immunity, help establish
a strong probiotic flora, protect against diarrhea and other bowel disorders.
6. Counteracting Infections
Urinary tract infections (cystitis)
Lactobacillus supplementation may help prevent recurrent infections.
A probiotic supplement taken regularly may help prevent chronic infections.
Gum and tooth infections
Take a probiotic supplement and rinse the mouth regularly with a solution
of 1 capsule of lactobacillus supplement to 3 ounces of water.
Vaginal infections (Clamydia, Trichomonas, Candida)
Take a probiotic supplement containing lactobacilli and douche regularly
with a solution of acidophilus, made same as above.
7. Irritable bowel syndrome
Long-term use of a lactobacillus or mixed-species supplement may help prevent
irritation and other symptoms of irritable bowel syndromes.
8. Chronic gas
After beginning a new probiotic supplementation program, one may find that
above normal amounts of gas are produced for a short while (up to a week).
This condition will normalize and gas may be reduced or relieved.
Ease into a probiotic program by taking 1/2 the recommended amount for a
week or two.