If you’re curious (we certainly are), you may have come across the topic of postbiotics, which are starting to be available in supplement form.
The science of postbiotics – including what they are, how they work, and whether to take a pill – is still in its infancy. Scientists don’t know much yet. We’ll get into that. But to understand what we know about postbiotics, you need to understand the basics of microbiome science, so we’ll start there.
The gut microbiome is made up of communities of different microbes – mostly bacteria and yeast – that live in the lining of our digestive tract. This microbiome develops and changes throughout our lives: our first microbes usually originate from our mothers during the process of vaginal birth and breastfeeding, and we acquire more of them during childhood, mostly from the food we eat. Genetics also play a role. In adulthood, the gut microbiome tends to stabilize, but it can still be altered by certain life habits, such as diet, as well as disorders such as stress, travel, antibiotic use, and certain prescription medications.
In a healthy microbiome most of these microbes are good for us or are somewhat neutral. They live in harmony with our bodies and perform functions that we cannot perform on our own, such as digesting certain foods and producing certain nutrients. Microbes that are not so good for our body beneficial usually control them because they compete for space in our bodies. Some disruptive events can lead to overgrowth of these not-so-good microbes, resulting yeast infections and conditions like excessive growth of bacteria in the small intestine (SIBO).
(Our bodies also have microbiomes outside the gut: We have microbial communities almost everywhere, like skin, mouth, and vagina.)
Although they often consist of bacterial species similar to those naturally present in the microbiome, probiotics are live and active cultures grown in a facility with the specific purpose of modulating the natural microbiome in the body. You find them most often in capsules. Some of them require cooling; others are stable on shelves. The types of microbes present in probiotic supplements vary. If you are taking probiotics for a specific purpose, the type you are taking is important: Like the microbes that are naturally found in your gut, the microbes in probiotics perform different functions in the body.
Probiotics are measured in colony-forming units or in active fluorescent units, not by volume or weight. CFU and AFU count the number of viable microbes per serving – which usually drops in the billions. Expect to see CFUs more often than AFUs: AFUs take advantage of newer, more accurate technology and include microbes that may not be included in the CFU (if the microbe is active but cannot be used, the CFU does not count), but not particularly often. A higher number of CFUs or AFUs is not necessarily better. The best dose of any probiotic strain is the one that has shown results in scientific studies.
The microbes in probiotics are transient, meaning they pass through the body and do not usually form permanent colonies in the gut. That’s why it’s important to take probiotics consistently – the probiotics you’re taking today won’t last long.
If you’re looking for a probiotic that will cover all of your bases, Seed’s Daily Synbiotic is a great option. Researchers from Seed have done their homework: Daily Synbiotic contains twenty-four clinically researched strains of probiotics, many in amounts that have been shown to be effective in scientific studies. Each serving of two capsules contains 53.6 billion AFU. That’s a lot, so if you’re new to probiotics, start with one capsule a day until your body adjusts. (This supplement also contains prebiotics, which we will cover below.)
A prebiotic is any compound that feeds bacteria in the gut. Usually, fibers that our bodies would not otherwise digest, such as inulin and certain oligosaccharides, are the ones that thrive in bacteria. This process is part of the reason we primarily have gut microbiomes. We do something good for them by providing them with food and a place to live, and they do something good for us by supporting various functions in our body, such as digestion and immunity. (In biology, this kind of reciprocity is called a symbiotic relationship.)
Prebiotics occur naturally in many plant foods; if you eat a diet rich in fruits, vegetables, and whole grains, you will probably take a lot of prebiotics from food alone. If you want extra support, you can look for a supplement that contains prebiotics. (Contact your doctor first: for people with certain bowel disorders, such as SIBO, prebiotic supplements can worsen symptoms.)
Pairing probiotic and prebiotic supplements can be helpful. Science suggests that prebiotics can help improve the viability of probiotics as they break through the gut. Some groups have begun to use the word “synbiotic” to describe a supplement that contains both prebiotics and probiotics, such as Seed’s Daily Synbiotic.
To summarize: congenital intestinal microbes and probiotics are active bacteria and yeasts. These bacteria and yeasts thrive by eating prebiotics. Postbiotics are what is left after these prebiotics are digested and fermented in the intestines.
The science of postbiotics is a field in the making and development. Most scientific research on postbiotics has been published in the last decade, and unlike prebiotics and probiotics, there is still no consensus on what is a postbiotic and what is not. For now, the word “postbiotic” is an umbrella term that represents all types of functional compounds that have been metabolized and fermented by microbes in the gut. Some can have significant benefits for our health and potential applications in medicine, while others may be just waste products. There are exciting things – resident goop dietitian Thira Burns believes that postbiotics may be the next big thing in food science. “We already know that eating fermented foods is good for the gut,” Burns says. “Postbiotic research can help us discover why.”
Like prebiotics and probiotics before them, some postbiotics are starting to be available as supplements. We want to be completely clear: scientists still don’t know if there is a full benefit to taking postbiotics as supplements, and we haven’t explained how and why these compounds work the way they work in the body. If you are looking for a supplement that contains a postbiotic, it is important to ask questions and research before buying. Some postbiotics have shown functional results in research settings and may be worth a try if these research results are consistent with your health goals. For example, there is fermented yeast with food EpiCor, which is considered a postbiotic and has been studied because of its connection with a healthy immune system. Because of that research, we included EpiCor in the formulation for Perfect Attendance, our immune support. And short chain fatty acids butyrate– a compound commonly found in the gut as a postbiotic – has been studied to support healthy bowel function.
This article is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis or treatment and should never be relied upon for specific medical advice. To the extent that this article contains the advice of a physician or physicians, the views expressed are those of the cited expert and do not necessarily represent the views of the goop.