The Microbiome: A Mega-Field That’s Just Getting Started

We are on the edge of something big, yet microscopic. Emerging research about the microbiome is hitting media outlets from large newspapers to small blogs. Consumers are eager to learn more and to harness the health benefits of this field. Unfortunately, the small amount of existing research, and a flood of media coverage, leave the topic of the microbiome vulnerable.  Fortunately, much research has been conducted in the past 10 to 15 years to clue us in on what’s on the horizon for the microbiome.

So what exactly is the microbiome? Let’s first talk microorganisms—what actually makes up the microbiome. Microorganisms include bacteria, fungi and viruses. These organisms can be found throughout your body. The largest microbial community resides in the gastrointestinal (GI) tract. You may have heard it referenced as "microbiome," the "microbiota" or the "microflora." The microbiome is densely populated. It has about 3.3 million genes (versus the human genome at 23,000 genes). Our bodies maintain a symbiotic relationship with these microorganisms: We feed them, and they provide us with essential health functions.

Some of these health functions are well-studied and others are unknown. For instance, we understand that a disruption in the gut microbiome, or dysbiosis, is associated with inflammation, metabolic diseases and autoimmune diseases. This inflammation is further associated with chronic diseases. We also know that we can set the stage for a healthy gut early in life.yogurt

This brings us to the question of how we can positively influence our microbiome. It’s no surprise that we have seen an increase in the amount of products featuring probiotics and prebiotics. But what exactly are these "biotics?" Probiotics introduce health-promoting microbes to the gut.  Prebiotics provide nutritional support for microbes already in the gut (or introduced through probiotics). Some examples of microbiome-promoting probiotics include Bifidobacterium, Streptococcus, and Lactobacillus. Naturally fermented foods including kefir, buttermilk, yogurt, kimchi and tempeh contain the highest amount of live, active cultures. It's important to remember that some foods that claim to contain "live, active cultures" may not have a enough quantity of probiotics to induce health benefits.

honeyPrebiotics result in specific changes in the composition and/or activity of the GI microbiome. They provide a food source for the beneficial bacteria. Inulin, polydextrose, fructooligosaccharides (FOS) and galactooligosaccharides (GOS) are common examples of prebiotics. Inulin, FOS, and GOS are found in foods such as bananas, honey, leeks, onions and garlic. Also, many fortified foods and beverages contain prebiotics to aid in digestion.  Some other dietary sources of prebiotics include Jerusalem artichokes, raw chicory root, raw leeks, dandelion greens and some legumes.

All around the world we see differences in microbiomes between people and even across cultures. This is due to dietary, environmental or other factors such as genetics. So probiotics and prebiotics affect us all in different ways. Because everyone has a unique community of microorganisms, we also do not know which prebiotic and/or probiotics will best help our inidividual microbiomes. Moreover, identifying a "best in class" strain to influence our microbiome is challenging and needs more research.

Lastly, probiotic and prebiotic health claims have not been approved by the FDA and the European Food Safety Authority. But does this mean these microbiome-supporting foods should not be encouraged? And how can we move forward with such limited information? To start, we can come to terms with what we do and don’t know and stay abreast of the most current research to help inform scientific and regulatory decision-making.

Bottom Line: What defines a healthy microbiome has not yet been identified. But the evidence surrounding the consumption of prebiotics and probiotics is strong enough to encourage incorporation of more of these foods. Although we do not have all the answers on the gut microbiome, we have quite a bit to "chew" on for now to impact health. 

Jana Wolf, dietetic intern, contributed to this piece.