Fundamental Knowledge – Differentiating Probiotics from Prebiotics
When choosing nutritional supplements, it is important to separate marketing jargon from scientific language. This empowers you to make informed health decisions. Probiotics and prebiotics are both advertised to improve gut health, but what are they and how do they work?
Probiotics are defined by the World Health Organization as “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host.” Nobel Prize winner Élie Metchnikoff recognized a correlation between long-lived Eastern European peasants and their heavy consumption of fermented dairy products. Studies have generally recognized that the colonization of the gut ecosystem by healthy bacteria contributes to good health by reducing intestinal pH and preventing infections from harmful bacteria.
However, regulatory agencies have called into question the effectiveness of increasing probiotic consumption to improve gut health. Much of this criticism stems from the fact that probiotics are live bacteria and in order for them to confer health benefits, sufficient numbers must survive the journey from the mouth, through the stomach, and into the colon. Generally, most probiotic bacteria die before they reach the colon.
Prebiotics are fundamentally different from probiotics. Prebiotics are not alive, but are actually the indigestible parts of our diet that are fermented by gut bacteria. Quite simply, prebiotics are food for probiotics – and for other healthy bacteria already residing in the colon. The term prebiotic was originally defined in 1995 by Marcel Roberfroid to be “non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacterial species already resident in the colon.”
Unlike probiotics, prebiotics naturally resist digestion, ensuring that they are available to exert beneficial effects in the colon. In fact, a recent study suggests that supplementation with prebiotics alone (without probiotics) is sufficient to renew the gut microbiome in the elderly.
Perhaps this is not surprising. Imagine the following analogy:
Your gut microbiome is a garden where the bacteria, including probiotics, are flowers. In a dry garden, planting more flowers (consuming probiotic supplements) will not improve the appearance of the garden because it will not improve the moisture content of the soil. In fact, those new flowers will likely suffer as well. But imagine that prebiotics are like water to the garden. Irrigating the microbiome garden with prebiotics allows existing plants to flourish, bloom, and spread the seeds for even more flowers.
In other words, consuming prebiotics allows your endogenous microbiome to flourish and may also provide food for probiotics, helping to ensure you maximize the benefits of your supplements.
It is ultimately up to you, the consumer, to experiment with different probiotics and prebiotics to achieve your desired gut health goals. Fortunately, consumers can take comfort in knowing that these products are incredibly safe and they can adjust dosages as they see fit, allowing for flexibility and adaptation to many of life’s other challenges.