Probiotics vs. Prebiotics: What’s the Difference?
Written by: Audrey Clement, RD
What are probiotics?
Probiotics are live microorganisms (bacteria/yeast), and when consumed in adequate amounts, can offer particular health benefits. They can be found in supplements and food sources. They are also living in our gut.
How do probiotics work?
There are multiple ways in which probiotics work to benefit our health. Many probiotics form SCFAs (short chain fatty acids) which strengthen our gut barrier to reduce the invasion of bad bacteria. Probiotics also aid in the synthesis of vitamins and enhance nutrient absorption. Many people will say that probiotics alter your gut which is not entirely accurate. They rather work to outcompete harmful microbes.
How can probiotics improve my health?
The most well established benefits of probiotics include improved immunity and digestive health. If you suffer from digestive issues such as uncomfortable bloating, irregular bowel movements, poor digestion of specific nutrients (lactose found in dairy), then a probiotic supplement can be helpful. Evidence also supports that probiotics can support brain function, cholesterol levels, weight loss, and overall metabolic health.
How can I get more probiotics in my diet?
Probiotics can be found in food sources and through supplements. Food sources of probiotics are called fermented foods. These foods include kimchi, sauerkraut, kombucha, kefir, yogurt, miso, tempeh, etc. Be mindful that not all fermented foods provide an effective dose of probiotics to support certain health benefits. Heat treatments used frequently in food processing can inactivate or remove live microorganisms. A great example of this is sourdough bread. Because the bread is baked, it will not contain microorganisms in the final product. Just because certain fermented foods may not contain the required levels of probiotics to elicit health benefits, does not mean that these foods cannot improve your health status. The food you eat is the most important component in supporting your gut health. Eating an abundance of fibrous foods and reducing intake of refined processed foods is the best place to start.
Example scenario of when to use a supplement:
I just came off an antibiotic and have been experiencing diarrhea for about a week. I have never struggled with irregular bowel movements before and nothing about my diet has recently changed. I eat at least 3 vegetables and 2 fruits per day and try to use whole grains when I can. I limit my intake of fast food and other highly processed foods.
Example scenario of when to use a food first approach:
I only go to the bathroom every 3 days. My diet primarily consists of processed meats and refined carbohydrates. I do not regularly eat fruits and vegetables.
What to look for when choosing a supplement:
Supplements should clearly define the genus, species, strain, and dose. Example: Lactobacillus (genus) acidophilus (species) NCFM (strain). Optimal dose of probiotic supplement should be between 1-10 billion CFU (colony forming units). The dose should align with the amount to elicit the targeted health benefit. Anything less may not be effective and anything more may not benefit you further. Work with a dietitian or medical provider to determine which probiotic would be best for the symptoms you are experiencing.
What are prebiotics?
Prebiotics serve as a food source for bacteria that is already in your gut (probiotics). Prebiotics include fermentable carbohydrates, polyphenols, and phytochemicals. To clarify, prebiotics can only be found in carbohydrate foods. The most studied prebiotics are in fermentable carbohydrates such as inulin, fructooligosaccharides, and galactooligosaccharides. Common food sources of prebiotics include: artichoke, leek, onion, garlic, bananas, whole wheat, asparagus
How do prebiotics work?
Prebiotics are not digestible and are utilized by microorganisms instead. Bacteria will metabolize prebiotics and produce byproducts which are linked to beneficial health outcomes.
How can prebiotics improve my health?
Prebiotics work to support digestive health, immune function, bone density, weight loss, blood sugar control, cholesterol levels, and reduced infections.
Prebiotics vs. fiber
Prebiotics are fiber but not all fiber is classified as prebiotics. Fiber provides health benefits but to be considered a prebiotic, the fiber must be utilized by microbes. Eating a diet rich in fiber will likely support adequate prebiotic intake.
Sample day of eating to support gut health:
Breakfast: Eggs with onion, peppers, avocado and whole grain toast
Snack #1: Greek yogurt containing probiotics and mixed berries
Lunch: Chickpea chicken salad on a whole wheat wrap topped with shredded cabbage and sauerkraut with an apple on peanut butter on the side
Snack #2: Smoothie with kefir, banana, spinach, and protein powder
Dinner: Roasted chicken with asparagus and sweet potato