You Get What You Pay For - Sometimes.
Probiotics ("pro-life") are supplements of beneficial organisms. Why would someone want to intentionally swallow a bunch of bacteria? Many consumers have become aware of some of the health benefits associated with such a practice. I believe the most common reason probiotics are purchased and consumed relates to their beneficial effect on gastrointestinal health. The average person has an estimated 100 trillion bacteria, weighing 2-3 pounds, residing in the intestinal tract. There are hundreds of species (researchers stopped counting after they got to 500), some good, others not so good for us. These intestinal bacteria are collectively referred to as the intestinal flora.
The intestinal flora has a multitude of functions. It can be thought of as an organ of the body (its metabolic activity rivals that of the liver). Most cancer-causing chemicals are not carcinogenic until acted on by intestinal bacteria. On a positive note, "good" intestinal bacteria detoxify carcinogens. They also produce vitamins and improve absorption. Many beneficial dietary constituents and nutritional supplements are not active until metabolized by the intestinal flora. The intestinal flora influences immune function, hormone levels, mood, energy production...all of the body's organs and functions. The state of your intestinal flora is one of the greatest influences on your overall health.
There are two basic guidelines I use in recommending probiotics. First, I sometimes have patients take a specialized stool test to measure the levels of different families of bacteria present in the intestinal tract and their metabolic byproducts. If there are low levels found, this is a reason to supplement.
Secondly, and probably more importantly, I recommend probiotics to achieve a specific effect. For example, if a person is taking a course of antibiotics (which disturbs the natural balance of intestinal organisms and can produce diarrhea) I might recommend a beneficial yeast called Sacchromyces boulardi. It is very effective for this application and I have seen it stop diarrhea almost immediately.
The strain of bacteria called Lactobacillus GG was found to reduce the development of allergy and atopy in children whose mothers took this supplement during pregnancy. This bacteria is a good choice for a pregnant woman to consider when there is a family history of allergy.
Lactobacillus acidophilus NCFM supplementation was found to reduce the frequency of the common cold and influenza. It has also been found to relieve pain from diverticulitis as effectively as morphine! There have been more than 50 studies done on this particular organism.
Lactobacillus plantarum 299v has been demonstrated to have a number of cardiovascular benefits. Supplementing this bacteria, believe it or not, has been found to lower LDL cholesterol, fibrinogen, systolic blood pressure, insulin, leptin, and markers of inflammation, and free radical activity.
To reinforce my point, What are you trying to accomplish by taking a probiotic? It is important to supplement with a strain of probiotic that has been demonstrated to have a specific physiological effect that you are looking for. If the bacteria are described on the label with general terms such as "acidophilus" or "bifidobacterium" it is most likely a worthless product. The specific strain must be identified by name.
The strain of bacteria should have research that it survives stomach and bile acid and adheres to the intestinal lining.
When it comes to probiotics, is more better? Yes and no. You do want to have a large number of organisms per dose (billions to hundreds of billions of organisms). On supplement labels, the potency of the bacterial probiotic should list numbers of organisms or colony forming units per dose. This is much more meaningful than listing the potency by weight.
I don't think you need to choose a product with the greatest number of strains of bacteria. The greater the number of strains, the lower the levels of each individual strain (and therefore its therapeutic effect). To think that a many-strain product will replace what is normally present in the intestinal tract just doesn't add up; you're not going to find a 500+ strain product. Also, when a number of strains are present in one product you have to wonder whether their levels will be negatively effected by competition among them during the shelf-life of the supplement.
When I find, on lab testing, low levels of many families of bacteria, I will recommend a prebiotic formula. Prebiotics are types of carbohydrates that "good" bacteria feed upon. If you feed the good bacteria, they increase in numbers and metabolic activity. Prebiotics can increase levels of many strains of intestinal bacteria at once. Biotagen is a very good prebiotic supplement.
Many people I speak with choose supplements based on price. That is a big mistake. The most expensive supplement is the one that doesn't work. Perhaps more so with probiotics than any other class of supplement, quality varies tremendously from one brand to the next.
A study examined the actual contents of 11 different Lactobacillus acidophilus supplements. Upon laboratory analysis it was found that only two of these products contained Lactobacillus acidophilus - and these did not have as much as they claimed on the label. The other nine products had strains of lactobacillus other than acidophilus and some were contaminated with Enterococcus and Clostridium.
I once had a product assayed that had lactobacillus acidophilus on the label. The laboratory found none in the product. Then I also had Ultra Flora Immune Health from Metagenics assayed. It contained the levels of Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07, which it claimed on the label. This is one of the probiotics I recommend most.