PROBIOTICS: IT’S THAT “GUT FEELING”

Published in Radius Magazine, Winter 2010

Back in 1907, a scientist named Elie Metchnikoff observed that peasants living in the Balkans appeared to have longer and healthier lives than other societies and postulated that it was because they consumed fermented milk products (i.e., yogurt). He theorized that the putrefactive processes in the intestines produced toxins that caused degeneration of the body and by ingesting certain “good” bacteria found in yogurt, these toxins could be negated.

Today, research is showing that Metchnikoff was correct in many ways. In fact, it is well recognized that our intestines contain an enormous amount of bacteria that are beneficial to not only the intestines, but to our general health as well. These “good” bacteria (also referred to as normal intestinal “flora”) are now known to have numerous health functions, as seen in Table 1.

One particularly important benefit is maintaining immune function. Approximately 80% of our immune protection takes place in the gut, which is important in sustaining a barrier against harmful substances that we ingest from our environment. In fact, infants do not have a fully developed immune system and it is thought that breast feeding prevents many allergies and infections because the mother’s milk contains these good bacteria.

TABLE 1
KNOWN FUNCTIONS OF “GOOD” INTESTINAL BACTERIA

Improve digestion Improve absorption of nutrients
Improve immune function Help move and remove waste
Production of B vitamins Repair/turnover of intestinal wall cells
Influences secretion of hormones Prevents yeast overgrowth
Prevents overgrowth of “bad” bacteria (including antibiotic-resistant),
parasites, fungi.

Enter Probiotics
Unfortunately, our lifestyles have changed dramatically over the past century regarding hygienic measures, diet, living standards, usage of medical drugs, use of preservatives, sterilized foods and chlorine in our drinking water, all of which can affect our normal flora adversely. Refrigerators and freezers have replaced the natural processes of food fermentation that produced good bacteria. Antibiotics in healthcare, agriculture, and in household products (such as toothpaste and deodorants) are detrimental to and can destroy these beneficial microorganisms. Additional factors that can harm our normal flora include infection, chemotherapy, radiation, and surgery.

It is now being recognized that such a decrease in intestinal flora can cause not only gastrointestinal medical problems, but also negatively affect our general health. It would thus make sense that by replacing the good bacteria that has been harmed or reduced, our guts can begin to function normally again and these medical conditions can be resolved or prevented. That is the purpose of probiotics, which are supplements or food sources that contain these good bacteria. Probiotic literally means “for life” and initial research now supports the possible benefits of taking them in various medical conditions (see Table 2).

TABLE 2
MEDICAL CONDITIONS THAT MAY BE RESPONSIVE TO PROBIOTICS

Infectious diarrhea Irritable bowel syndrome (IBS)
H pylori infection (ulcers) Tooth decay, periodontal disease
Vaginal Infections Daycare-acquired stomach/lung infections
Skin infections Lactose intolerance
Viral gastroenteritis Atopic dermatitis (eczema) in children
Endstage liver disease Boost immune system (colds/flu)
Colon cancer preventative HIV enteropathy
Prevent urinary infections Infection with C difficile
Pouchitis Reduce recurrence of bladder cancer
Inflammatory bowel disease (IBD) (e.g., Crohn’s disease, ulcerative colitis)

What Exactly Is In A Probiotic?
There are numerous types of good bacteria living in our guts. In general, there are two groups: bacterial (lactobacillus, bifidobacterium, streptococcus) and yeast (saccharomyces). Within each of these groups are numerous species and within each species are multiple strains, each of which may have separate functions. Different probiotic products contain either a single strain or various combinations (see Table 3).

In addition, there are foods that contain probiotics, referred to as functional foods. Some naturally contain beneficial bacteria and others have them added. Although most yogurts contain natural flora, many yogurt products may not contain the important species or the bacteria is destroyed in the manufacturing process. Activia, DanActive and Align are specific probiotic-added yogurts that are advertised widely and are found in most grocery stores. Other foods that contain good bacteria include sauerkraut, fermented and unfermented milk, foods that are “pickled”, miso, tempeh and some juices and soy beverages.

TABLE 3
SOME COMMON PROBIOTIC FORMULATIONS

Probiotic GI (Lactobacilli acidophilus and casei; Bifidobacteria bifidum and lactis; Strep.
Thermophilus)
Allipro (Lactobacilli acidophilus, rhamnosus, salivarius and plantarum, Bifidobacteria bifidum)
Culturelle (Lactobacillus GG)
VSL #3 (Lactobacilli casei, plantarum, acidophilus, and bulgaricus; Bifidobacterium longum,
breve and infantis; Strep. thermophilus)*
Probiotica (Lactobacillus reintera)
Flora-Q (Lactobacillus acidophilus)
Floraster (Saccharomyces boulardii)
Activia (Bifidus regularis)
DanActive (Lactobacillus casei)
Align (Bifidobacteria infantis)

*Must be refrigerated

Which probiotic is most effective?
Obviously, there are many different probiotic combinations (also referred to as bacterial “cultures”) as well as single strains, so how do you know which one to take? Although specific benefits have been demonstrated for some strains, many of the actions and benefits of our intestinal flora have yet to be fully determined.

Additional factors can also dictate the benefits you receive. For one, cultures must remain stable during storage; many have to be refrigerated to survive and die off quickly if not. Furthermore, probiotics must be delivered primarily to the small or large intestines, where most of their beneficial functions occur. Some formulations will not survive the passage through the stomach and bile acids.

There are also many forms of probiotics, such as the liquid yogurt products. To improve stability, many cultures are freeze-dried into powder, capsule or tablet form, which improves the chances for the bacteria to survive the passage to the small/large intestines. Many of the pharmaceutical products are in gelatin capsules, but they contain 10-15% water which decreases stability and viability of the cultures. Products that have regulated disintegration (primarily tablets and capsules) are usually the best, since this continuously exposes the intestinal system to viable bacteria.

There is also a matter of the quantity of bacteria in the probiotic product. This can vary from 1 billion to 450 billion per capsule or dose. This varies so much because each species has different characteristics, some are stronger than others, some are destroyed more easily either before being ingested or while traveling through the intestine, some medical conditions require larger amounts of bacteria, and differing amounts are needed depending on where the bacteria end up (e.g., the large intestine requires higher counts than the small intestine).

What this means is that the initial amount of bacteria in the product may not correlate with its eventual benefits. What is most important is how many bacteria are available at the time you take the product. Be aware that many probiotic products do not deliver enough good bacteria to have a beneficial effect. In 2006, ConsumerLab.com evaluated 13 popular products and found that 9 out of the 13 had low levels of viable bacteria (less than 1 billion) at the time of purchase.

Thus, the effect of the supplement is influenced by the choice of bacteria, the amount of bacteria, the quality, viability and stability of the bacteria and how the bacteria is distributed from the mouth to the intestine. Unfortunately, there is no easy way to know which formulation will work for you and often, you just have to try different brands to see which works the best. In general, I recommend non-refrigerated tablets or capsules that contain several different strains of bacteria (see reference below).

What About Prebiotics?
Prebiotics are complex carbohydrates that are sometimes taken with probiotics to boost their effectiveness. Prebiotics are not broken down by enzymes in the stomach or small intestines, so they can reach the large intestine in viable form. They then stimulate the growth and activity of added probiotic bacteria as well as the normal flora already in the colon. Although some products contain both prebiotics and probitoics, prebiotics can be taken separately by taking additional supplements (such as fructooligosaccharide [FOS], inulin or allicin) or adding bran, psyllium, or germinated barley foodstuffs (GBF) to your diet. In fact, these prebiotic-containing foods are often recommended if you have IBS or IBD. Many other foods contain natural prebiotic carbohydrates as well, including most fruits, barley, garlic, onions, whole grains, leeks and honey.

Safety
There are little to no side effects or concern about taking probiotics. The most common side effect is flatulence, which can improve on its own or by changing to a probiotic that contains different bacteria. However, it is not known whether probiotics can harm people who are immune-compromised, so they are not recommended in such conditions.

The Future
The first proven beneficial probiotic was developed in 1983 (called Lactobacillus GG), yet the researchers could not get either pharmaceutical companies or academic medical centers in the U.S. to become interested in further studies. It is only now that alternative medicine has demonstrated the wide ranging benefits that conventional medicine has decided to investigate these supplements.

Even so, most people are not waiting for the research. In our country, spending on probiotics nearly tripled from 1994 to 2003. In Japan, the world’s leader in probiotic usage, probiotics are available in vending machines to a much greater extent than soft drinks. In Spain, DanActive outsells Coca Cola. In Europe, many physicians now routinely give probiotics to patients who take antibiotics.

Until more research is done, however, it will be difficult to know exactly which strains and which formulations will help which conditions the best. At this time, definitive claims cannot be made that probiotics are effective against specific diseases, but we can say they have a beneficial effect on our health as a whole.