These days, it seems like prebiotics are all over the news. Every article has some new claim regarding prebiotics: they heal your gut, they boost your mood, they prevent disease. Why the prebiotic pandemonium? Are prebiotics really as amazing as they’re made to appear?
The Prebiotic Defined
And what does “prebiotic” even mean? Nope, it isn’t just a fancy term for fiber. A prebiotic is something in your food that can’t be broken down by your digestive system, can be broken down by your gut bacteria, and helps gut bacteria work or grow (1). In short, prebiotics act as “microbiome fuel” and help certain microbial members thrive! While many prebiotics are dietary fibers, not all dietary fibers are prebiotics, as there are some types of dietary fiber that even our mighty gut bacteria can’t break down (2). Not all prebiotics are fibers either – the group includes non-fiber products such as human breastmilk sugars, and could potentially include micronutrients found in cocoa, coffees and teas (1). Many unprocessed, plant-based foods (such as bananas and garlic) contain microbe-pleasing prebiotics (3).
What Qualifies as a Prebiotic?
Typically, food chemicals attain prebiotic status by being used as sources of gut bacteria energy and so allowing their numbers to grow (1,4). This can help the general health of their kind hosts (us!) in several ways. For one, more “good” bacteria can mean less “bad” bacteria, as there is less room for “bad” bacteria to grow (5,6). Bacteria also release many important byproducts when breaking down undigestible stuff in our food (7). One such byproduct is short-chain fatty acids (SCFAs), can inhibit inflammation and feed your colon cells (8). Only certain types of gut bacteria can effectively break down certain prebiotics to create certain beneficial byproducts (7), so it’s important to diversify your prebiotic-packed diet.
The Health Benefits of Prebiotics
Though research focuses much more on dietary fiber than on prebiotics, ingesting this “microbiome fuel” could help combat several health maladies. Prebiotics may increase immune system function in a number of ways, from increasing levels of immune system signals (9) to potential improvement of responses to flu vaccines (10,11). Certain prebiotics are also thought to lower triacylglycerols (12), fats found in your blood that correlate with metabolic syndrome and heart disease (13). Non-human studies suggest that eating prebiotics could guard against gut infections by blocking disease-causing bacteria from attaching to and growing in the intestine (14,15). One human study suggested that they may also reduce tumor growth in colorectal cancer when combined with probiotics (16). However, prebiotics may not help all GI tract issues – effects on irritable bowel syndrome (IBS) and Crohn’s have been mixed (17).
Prebiotics and the Brain-Gut Connection
Prebiotics may affect not just your body, but your brain as well. Prebiotic consumption can increase levels of chemical messengers (neurotransmitters) and important neural proteins in rats (18,19), implying that consumption could affect brain function. Several human studies have suggested that prebiotics may improve memory and cognition (17,20,21). The effects on mood, however, are less clear. While gut health is known to affect the brain (22), current research suggests that prebiotics themselves don’t ease depression or anxiety symptoms (23), though more studies are likely needed.
Prebiotics are amazing. While they may not affect every aspect of wellness, they can boost your health and make your gut microbes happy too. Keep eating plenty of fruits and veggies to fuel your gut, and you! And make sure to take your digestive enzymes so you can properly absorb all the nutrients from those fruits and veggies!