PROBIOTICS - do they make the GRADE?

There are books on this topic.  I am going to just give you an overview
1.  Making the Grade
2.  The probiotic microorganisms
3.  Important health effects of probiotics
4.  Safety of probiotics
5.  Types of foods with probiotics

MAKING THE GRADE
For an organism to be considered a probiotic (and by extension, a probiotic food), it needs to have a positive effective on health in humans (not just rats!).  In addition, it should be safe and nontoxic.  The studies done have to be on the specific organism, not on a related species, because close "relatives" do not always have the same physiologic effect in humans.  Other values that have to be taken into consideration include the number of viable organisms ingested to have the health effects and are they still effective at the end of the expiration date.  And don't forget the age, health, gender and race of the person taking the probiotic can affect whether or not something works.

PROBIOTIC MICROORGANISMS

These organisms meet the following criteria:  they are are not toxic or pathogenic, are originally from the guts of healthy people, and can pass through the stomach without losing their effectiveness before they get to the intestines.

Lactobacilli -bacteria found in abundance in the gut of humans
Bifidobacteria - another group of bacteria found in abundance in the normal human gut.

Other probiotic organisms that are found in normal humans but in smaller amounts include some forms of enterococci, streptococci, lactococci,  and some yeast.

HEALTH EFFECTS
The intestine is extremely involved in the immune system both through how it breaks down the foreign bodies that enter into it (food included) as well as its extensive lymphoid system.  The balance of the different organisms in the intestine will change the pH, the production of substances that kill or allow the growth of different types of bacteria and weaken or strengthen the barrier of the intestinal mucosa.  This is where the probiotics are able to enhance health.
There are many scientific studies that try to measure the health benefits.  Some are done well, some are poorly done, some are difficult to do, and some are waiting to be done.  As it now stands, based on the good studies, the scientific community generally accepts that probiotics do the following:
1.  Decrease the symptoms of lactose intolerance
2.  Prevent or reduce both rota virus and antibiotic-caused diarrhea.
3.  Increase remission periods in people with inflammatory bowel disease

There are some studies that show conflicting reports, and the effects are only in certain groups:
1.  Some regulation in gut motility (improvement in some groups with irritable bowel syndrome)
2.  Improvement or resolution of allergies and atopy in infants, but not older patients

And then in some studies things work in the lab, but so far not in people
1.  Cancer prevention
2.  Decrease cholesterol and protection for heart disease

SAFETY
Probably the best way to think about this is that lactic acid bacteria and bifidobacteria have been used for millenia and have been safe.  Also, when they have actually been looked at, there is no evidence that probiotic products are riskier than are similar products that do not have probiotics added to them.  Also, studies done on patients with leukemia and HIV who were taking probiotics did not have increase infections with lactobacilli.

TYPES OF FOODS
Probiotic foods are different from probiotics in that that have to continue to maintain their efficacy throughout production and shelf life.  They also have to be something that you want to buy which means that they look and taste good for most people.

Fermented Milk Products
Yogurt is the most popular type of probiotic food.  Many yogurts on the market actually do not fit the criteria of being a probiotic.  They do not have live cultures, or do not have the organisms that qualify as probiotics.
Hard cheese is difficult to produce as a probiotic, although fresh cheese is easier.  Unfortunately, the manufacturing process of any cheese tends to kill off the bacteria.  To date all the studies testing the effects of the cheese were done in animals and there are no  marketable cheeses so far.

Other potential foods include ice cream and other sweets, but that kind of defeats the purpose in my mind.  Vegetables have not been tested.  There is some talk about spraying probiotics on salami, but no testing so far.  There have been some studies of probiotic milk powder, but no information on its stability and efficacy.  It could be used in powdered milk, formula etc. if it is successful.


BOTTOM LINE ON PROBIOTICS
Probiotics have scientifically been shown to be safe and have a positive health effect, but not as extensively as what has been claimed in the lay press.  At this point, the only way to get it in food is through yogurt.

On to PREBIOTICS in the next blog.