Welcome to Nutrition Bites. The no nonsense podcast where you get the truth about food so you can eat what you want, and be healthy. I’m your host Maggie and welcome to the series. Despite its reputation as a goopy and gross place, our gut hosts an incredibly complex world of microorganisms. With such a big influence on how we feel, trying to create a healthy microbiome is a goal for many. On the menu today, pre- and probiotics.
For most of my life I suffered with a sensitive stomach. One day I would feel sick because I ate too many grapes, the next, because I didn’t eat enough of them. The following week I would have a new food to blame, and on and on it went. For many years I just thought this was something I had to live with - a biological bad roll of the dice. It turns out that most of my digestive issues were due to stress, not some culinary culprit. But it took years to find that out, and that’s because up until a decade ago our guts were largely ignored in health science. I mean digestion is a pretty gross process, and if I had to choose something to research I wouldn’t select the one related to poop. But in the mid 2000s the gluten-free movement helped popularise investigating gut health. Now we know that you can’t have a healthy gut without making sure the local microbial residents of your digestive tract are also happy. And two ways to encourage a merry microbiome are by taking pre- and probiotics. But these terms often elicit a lot of confusion - not just their difference but what they even do. So let’s find out more.
Bacteria, viruses, and fungi may conjure up scary images of damp basements and rotting fruit but the truth is, it is estimated we have more microorganisms living in our body than we have cells that make us, us. Not to get all philosophical, but that kind of means our bodies are less like vessels for our soul and more like a planetary home to a bunch of microbes. Spooky right? Now the vast majority of our body’s tens of trillions of microorganisms, live in our digestive system, and their populational mix is as unique as our fingerprints. Hundreds of different strains of microorganisms call our gut home, and scientists strongly believe that this demographic mix influences our metabolism, hormones, immune system and mental health. Our microbiome contains both “good for us” and “not good for us” microorganisms, but so long as a specific balance is met, we stay healthy. But in situations where there are more “bad” bacteria or yeast than the good guys, it ain’t a pretty picture. An imbalance in our gut microbiome can cause temporary issues like diarrhoea and are also hypothesised to contribute to long-term conditions like bowel disease, obesity, and cardiovascular disease.
Because of how important the microbiome is to our health, people have become increasingly interested in curating, and maintaining, the right mix of microbe populations. Almost like a real-life, internal, version of Neopets - the classic 2000s virtual pet game which I was obsessed with. Except when it comes to your body’s microbes you have trillions of little pets to take care of. And this is where pre and probiotics proclaim to help. When taken in specific amounts, both of these products can have a positive health effect on our body. But what exactly do they do?
As defined by the International Scientific Association for Probiotics and Prebiotics (because there is a society for everything), prebiotics are substances that act as food for the good microorganisms in our gut. Our diet heavily influences the health of our microbiome. After all, what we feed ourselves is also eaten by the microorganisms in our digestive tract. Studies have shown that eating a lot of highly processed foods can lower the number of “good” bacteria in our gut. While on the flip side, eating a diet full of fibre, fruits, veggies and legumes, supports our digestive health. And prebiotics help support in an even more specific way.
Prebiotics are compounds in food that promote the growth or activity of good microorganisms in our gut. They are most often a type of fibre, and are naturally found in foods like garlic, onions, apples, kidney beans and chickpeas. These days, prebiotics can also be extracted from plants or synthesised from sugar, making them an ingredient easily added to foods or dietary supplements. You’ve likely seen, and probably eaten, prebiotics such as inulin, also labelled as chicory root, which is often used in high-fibre granola bars and cereals. Now the difference between prebiotics and regular fibre can be a bit blurry but this is the main distinction. Fibre is a type of carbohydrate that may be fermented by our gut microbes, but also may just pass right by and help with other bodily functions like keeping us regular. Prebiotics on the other hand, are a type of fibre that selectively fuels specific, good-for-us microbes. Think of this targeted effect as like a secret, bougie menu item for our gut’s VIPs.
But what happens after these good bacteria and yeasty boys feast on prebiotics like the students of Hogwarts during the holidays? Well first, and most obvious, they help promote the growth of beneficial bacteria in our gut, which keep the balance between good vs bad strains in check. Second, when these good bacteria eat prebiotics they produce specific compounds that are beneficial for our health. Research has shown that special small molecules, called short chain fatty acids, are produced when bacteria ferment prebiotics. These specific molecules act as messengers to other organs in our body, helping to moderate our appetite, metabolism, blood sugar, and immune system. Scientists have also discovered that prebiotics can directly help improve bowel habits, and increase the absorption of some minerals from food. Because of all these combined effects, many researchers think that prebiotics could help prevent, or manage, conditions like osteoporosis, diabetes, colon cancer, and IBS. Pretty big clout for a type of fibre if I may say so. But here’s the catch. We are still at a point in research where it’s difficult to be prescriptive with prebiotics. To date, there is no official recommendation for prebiotics and they’re more so seen as a “nice to have” component of your diet, rather than a “need to have”.
Fortunately for the gut geeks out there, probiotic research is a little further along. And for those who have yet to be educated by Jamie Lee Curtis’ Activia yogurt commercials, probiotics are live microorganisms that can have a positive effect on our health when consumed in specific amounts. Probiotics are particularly helpful in cases where someone's microbe mix is out of whack. In order to reestablish a healthy microbiome, the body only needs a few good guys to start re-growing, and probiotics can act as that new colony starter kit. Similar to prebiotics, probiotics are also present in foods we eat - fermented foods in specific. If you recall Episode 8 of the podcast, fermented foods utilise live microbe cultures to transform the taste, texture and composition of foods and drinks. In fact, probiotics were first discovered thanks to fermented foods. In the late 1800s a scientist deduced that the long life expectancy of the poor, rural people of Bulgaria was due to the “good” bacteria present in their daily fermented milk. In addition to fermented foods, probiotics can also be found in supplements or used as ingredients in foods like yoghurt.
Research into probiotics has been going on for a while, with evidence suggesting that they can produce vitamins and helpful enzymes (like lactase), and more importantly, assist with issues related to immune and digestive health. In particular, research shows that probiotics can help reduce certain types of diarrhoea, improve mild symptoms of IBS, and decrease vaginal infections - an organ which has its own unique microbial environment. The details of how probiotics help these issues is still not exactly clear but the big picture idea is that it’s all about restoring balance after disruption to the microbiome mix. Both yeast infections and antibiotic-associated diarrhoea are caused by not enough “good” microbial strains in their respective organs. So by taking a probiotic containing specific good-guy microorganisms, our sensitive microflora populations can bounce back to normal. What’s important to remember though is that not all probiotics are created equal. For example, only certain species and strains can be used to alleviate diarrhoea from antibiotic use, and if you don’t take the right probiotic, well then you are quite literally shit out of luck. So how do you know which ones to take?
Unfortunately this is the big ticket question that everyone would like the answer to - including many health care providers. So far, scientists have only linked a couple of probiotics with a known health effect - like lactobacillus acidophilus as a preventative treatment for yeast infections. But for all the other more buzzworthy effects of probiotics, from weight loss to glowing skin, very little is known. And that’s not without good reason - probiotic research is really difficult.
For one, it’s hard to study the effects of specific species and strains on our health when the amount of microorganisms in a probiotic supplement is so tiny. Compared to the quantity of microbes in our gut, taking a probiotic is like adding a single drop of water to the Atlantic ocean. Most supplements, and foods or drinks with probiotics, contain about 1 billion CFUs (the unit for counting bacterial cells) per strain. Even if a probiotic pill contains 12 different strains that’s still only 0.01% of the approximate 100 trillion microorganisms in your body. Not only does this make it extremely difficult to attribute any health effects to a probiotic, but it also makes permanent changes impossible. Probiotics only cause temporary changes to our microbiome populations, rarely lasting more than a few weeks. Their role is to seed the growth of microorganisms with reduced populations, and once their volume is revived, there’s little use left. This is why many scientists don’t recommend probiotic supplementation if you have a healthy microbiome. It’s just really not going to change much at all.
Another factor as to why the health effects of probiotics are not as wide-ranging as we’d expect, is because the actual quantity of live microorganisms delivered to the organ of interest is much lower than we think. Our bodies are an incredibly scary destination for microbes - which is a good thing, most of the time. Take our stomach acid for example. It’s designed to destroy and kill almost anything alive that we eat. So regardless of the amount of a probiotic you take, it’s really difficult to determine the exact quantity that survived their journey. This quantity conundrum also extends to fermented foods. For one, we have no idea how many live microbes were used in the making of a product. And two, depending on the processing of the food or drink, you may end up with dead microorganisms in the end with no probiotic effect at all.
But let’s not dwell in the dark place for too long, because there is a lot to be excited about in this field. It’s an area of research with a lot of interest and funding. Just a few days ago a group of scientists announced a new way to deliver probiotics more effectively to our gut, essentially bypassing death by stomach acid. And while prebiotics is a much newer field, having only been classified in the mid-90s, their popularity is also increasing. Today you can find so many products with prebiotics from granola bars to cereals to sodas and sparkling waters.
But before you go too koo-koo for kombucha, there are a few tips I’d like to share to help guide you on your venture into the world of pre- and probiotics. Although there is no recommended quantity of prebiotics you should eat, some organisations suggest setting a target of 5 grams of prebiotic fibre a day. Now that can be difficult to determine if your source is whole veggies and beans, but it’s something to keep in mind if you are buying a food or drink with added prebiotics. When it comes to probiotics, there is also no set daily amount, but in general you should be aiming to consume at least 1 billion CFUs per species listed in the product. Any less and it will almost certainly do nothing for you. As for the types of probiotics to keep your eye on, choose a food or supplement with at least one of the 3 most commonly studied genuses: bifidobacterium, lactobacillus and saccharomyces. Aka biffy the gut slayer, tic-tac-lacto and sacred sacchro. Now if you prefer to get your microbes from fermented foods, look for labels that include the words “live” or “active” cultures to make sure you’re actually reaping the probiotic benefits of these funky foods.
When it comes to recommendations for improving gut health, most experts suggest getting good sleep, eating lots of fibre, and keeping your stress levels in check (easier said than done). But pre- and probiotics can have a place too. Sure, they are both more “nice to have” not “need to have” additions to a diet (especially if you are already healthy), but there are really no negative effects of consuming these products, so why not give them a go? You can try focusing on eating foods naturally high in prebiotics, or perhaps choose a granola bar with prebiotics on your next grocery trip. Similarly, you can add probiotic yoghourt or more fermented products in your diet. Supplements are also available too, just don’t spend too much money on them - after all, we don’t even know how much they help. At the end of the day, you have trillions of little microbes sharing your body, so you may as well be a good host and keep them happy.
That’s been the bite for today. Stay hungry.