AUTHOR: Dr. Jason Bush

The concept of an ecosystem rich in diversity evokes thoughts of dense forests whose canopies cover thousands of birds, mammals, reptiles, and insects.  While difficult to imagine, a similarly diverse ecosystem exists inside our digestive tract, also known as the gut.  Here, hundreds of species of bacteria reproduce, exploiting nutrition that resists the body’s digestion and functionally interacting with the colon cells.  Understanding how bacterial diversity in the gut relates to good digestive health may help you decide which probiotics and prebiotics are best for you.

The growth of healthy gut bacteria is determined by the foods we consume, especially foods or supplements containing prebiotics.  But the idea that eating prebiotics increases healthy bacteria implies that all healthy bacteria simply eat prebiotics.  This is misleading because it doesn’t take into account the ecological system in which these organisms live.  It may also lead to confusion in which probiotic supplements to use.

Only certain bacteria have the ability to ‘eat’, or obtain energy from, prebiotics.  Think of these primary bacteria as specialized predators capable of capturing prebiotic prey.  Perhaps most surprisingly, primary bacteria do not provide the most important health benefits associated with the gut microbiome – these come from ‘scavenging’ secondary bacteria.

When prebiotics are first broken down, the primary bacteria consuming them ‘eat’ only a portion of the prebiotics.  In other words, when primary bacteria consume prebiotics, they leave a lot of leftovers.  Importantly, these leftovers supply food to other species of bacteria, an event known as cross-feeding.  Remember, these secondary bacteria confer important health benefits.

Returning to the concept of the forest ecosystem, wolves successful in hunting a deer feed themselves, but numerous birds also benefit by feeding on whatever the wolves leave behind.  Those scavengers might not survive if the number of wolves decreased.  However, the presence of numerous other predators (and therefore other sources of ‘leftovers’) in the diverse forest ecosystem means that the population of scavenging birds is not threatened.  Diversity in the forest ecosystem is the key to resisting environmental challenges.

Diversity in gut bacteria is similarly essential:  Without primary bacteria to break down prebiotics and supply food to secondary bacteria, the body misses out on important health benefits.  Even worse, a bacterial ecosystem lacking diversity allows harmful opportunistic bacteria to grow and spread in the gut.  Furthermore, gut microbiome diversity is under constant stress from environmental factors, such as diet, illness, and especially antibiotics, making loss of diversity a serious health concern.

Fortunately, the gut microbial ecosystem is resilient and despite the loss of healthy bacteria due to medicine, dietary changes, or even age, revitalizing the ecosystem is simple and easy.  While supplementation with probiotics may help, research shows that the consumption of prebiotics is sufficient to return diversity and balance to the gut microbiome ecosystem – at all levels.  Prebiotic supplementation is also a good way to prevent the loss of microbiome diversity.

For those suffering from digestive issues, especially those that are age-related, prebiotic supplementation offers a straightforward, drug-free way to renew your gut microbiome diversity and enjoy the benefits of a balanced ecosystem.