Probiotics vs. Prebiotics — What You Need to Know
by Natasha Trenev
Probiotics are deﬁned as “live microorganisms which when administered in adequate amounts confer a health beneﬁt on the host,” or, as we like to think of them, simply beneﬁcial microbes, most often of the bacterial kind. Prebiotics are deﬁned as “a substrate that is selectively utilized by host microorganisms conferring a health beneﬁt,” or simply thought of as the food source for the probiotics.
Prebiotics are a class of simple carbohydrates that are non-digestible by humans and are found naturally in foods such as leeks, asparagus, chicory, Jerusalem artichoke, garlic, onion, wheat, banana, oats, as well as soybean. However, you would need to consume a large quantity of these foods for them to have any useful prebiotic effect.
Prebiotics are designed to feed the probiotic supplements and encourage their growth and to feed the bacteria already found in our gut. It sounds like it makes common sense to combine them so you have the total package of the probiotics and the food they need to survive and thrive. Unfortunately, that’s only half of the story.
Prebiotics Feed the ‘Bad’ Bacteria, Too
Prebiotics are designed to provide the beneﬁcial bacteria in your GI tract with a food substance that encourages their growth. However, when you take a prebiotic, you have no control over which bacteria are beneﬁting and proliferating because of it. Therefore, you may be feeding the bad bacteria along with the good bacteria. Scientiﬁc evidence has shown that by taking a prebiotic, we are also encouraging yeast growth and the growth of potentially harmful bacteria such as Klebsiella, E. coli, and Salmonella. Klebsiella has been identiﬁed as one of the “big three” gram-negative pathogenic bacteria with growing antibiotic resistance in the United States and abroad.
If the balance of bacteria in your gut is already unhealthy and skewed in favor of bad or potentially pathogenic bacteria, taking a prebiotic may just help these species proliferate and make the balance worse.
Prebiotic Side Effects Can Be an Issue
In addition, studies have shown that one commonly used prebiotic known as Fructooligosaccharide (FOS) actually can impair the intestinal barrier (this is exactly what most people are trying to prevent by taking probiotics in the ﬁrst place). And you might be shocked to know that the list of side effects associated with FOS include diarrhea, abdominal rumbling, bloating, cramping and excessive ﬂatulence. Many people take probiotics to help with digestive upsets, so why would they want to add on a prebiotic with known side effects like this?
Another commonly used prebiotic is called inulin. Inulin is a complex sugar found and extracted from the roots of various plants. Researchers from the University of Helsinki and the University of Montana studied mice fed with inulin prebiotic diets, and discovered shifts in the total bacterial community, including the discovery of previously unknown bacterial strains. Other studies have reported the increased potential for intestinal tumors and colon cancer in mice fed inulin supplemented diets. These studies strongly suggest a negative aspect to the use of inulin as a prebiotic.
The Intrinsic Supernatant
All probiotics are live organisms that require nourishment in order to survive and ﬂourish, and what sets some probiotics apart from the rest is knowing if they contain their own intrinsic supernatant or not. During the process of making probiotics, the live bacteria must be provided with a nutritionally-balanced food base formulation that is speciﬁcally selected for each bacteria strain to optimize the potential health-promoting properties of the bacteria. This food source allows them to grow, multiply and thrive. As the bacteria grow, not only do they transform this surrounding ‘food’ (aka culturing medium) into an active and very essential byproduct known as the supernatant, but they also produce and release very powerful active substances like hydrogen peroxide and acidophilin and vitamins into the supernatant. These byproducts then enhance the health properties of the probiotics.
The supernatant becomes the natural food source and therefore the natural prebiotic speciﬁc to the probiotics being grown. The problem is, during the manufacturing process, many companies exclude this important growth medium in favor of collecting higher numbers of bacterial cells into their ﬁnal product. It’s an added expense to include the intrinsic supernatant in the ﬁnal probiotic product. However, the beneﬁt to the consumer is that probiotics that include the intrinsic supernatant (aka growth medium) are carrying their own food source with them so there is no need to combine them with additional prebiotics. Since the supernatant already provides speciﬁcally designed food for the good bacteria, there is no need to add ﬁllers such as FOS or inulin to these probiotics.