Are you wondering how to keep your gut bacteria happy while on the low FODMAP diet? Then prebiotics might be the answer! Many foods that are high in prebiotics are also high in FODMAPs – this is why the reintroduction phase of the low FODMAP diet is important. However, there are plenty of low FODMAP prebiotic foods you can enjoy.
What are prebiotics? And How Are They Different to Probiotics?
Probiotics are defined as “live microorganisms (bacteria) that, when administered in adequate amounts, confer a heath benefit on the host” (1). These probiotics can include lactobacillis & bifidus found in yoghurt.
In contrast prebiotics are food for our good gut bacteria. Prebiotics are when the food itself provides nourishment for the bacteria in the gut and include specific types of fibre (2). The non-digestable carbohydrates (prebiotics) that are in the foods we eat, travel through our digestive system to our large intestine, where they are then fermented (eaten) by our gut bacteria. This fermentation can cause gastrointestinal symptoms like gas and bloating.
The low FODMAP diet restricts the intake of many high prebiotic foods (like garlic and onion) because it limits the consumption of fructans and galacto-oligosaccharides (GOS), which are known to cause gastrointestinal symptoms (3). Over time these restrictions of high FODMAP prebiotic foods can cause our gut microbiome to change, and this is why you are encouraged to reintroduce high FODMAP foods. If you are in the elimination phase of the low FODMAP diet, it can be beneficial to seek out low FODMAP foods that contain prebiotics.
8 Low FODMAP Prebiotic Food Sources
1. Buckwheat Groats / Kernels
Although buckwheat sounds like it belongs to the wheat family, it is actually a fruit seed grain related to rhubarb. It is classified as a cereal grain and it is low FODMAP in small serves. Buckwheat is also a wholegrain and it contains prebiotic properties (4). If you are in the USA you can enjoy a ¾ cup serve of cooked buckwheat, if you are outside of the USA then test your tolerance to a ¼ cup serve (5).
Recipe idea: Try buckwheat porridge!
2. Rhubarb
Accredited practising dietitian, Joanna Baker, recommends rhubarb as it is high in fibre and contains prebiotics. Rhubarb is a tangy tasting vegetable, which is often mistakenly classified as a fruit! Just make sure you don’t eat rhubarb leaves as they are poisonous.
Recipe ideas: Create a strawberry and rhubarb crumble, or top your rice cakes with stewed rhubarb and raspberries.
3. Banana (unripe)
Another easy to access prebiotic food is banana (6). Bananas actually contain small amounts of inulin (which by itself is high FODMAP), however the amount of inulin is low enough to fall within the low FODMAP threshold providing the banana is unripe. Be mindful that ripe bananas are high FODMAP for fructans. Unripe bananas also make a great low FODMAP snack.
Recipe idea: Try making frozen banana bites for a tasty treat.
4. Common or Red Cabbage
Cabbage is known for being high in fibre but it is also beneficial for our gut bacteria as it contains prebiotics (7). Both common and red cabbage are low FODMAP in one cup serves and are a great way to meet your daily fibre needs. My favourite is purple cabbage (I love brightly coloured foods!).
Recipe ideas: Try shredding some cabbage into your next low FODMAP coleslaw, or roasting it with some olive oil.
5. Kiwifruit
Kiwifruit are an awesome low FODMAP food… they are high in fibre (2 kiwifruit a day is a great first line treatment for constipation), full of nutrients like vitamin C, K, E, potassium, and magnesium, and they are packed full of prebiotics (8 9 10). Kiwifruit also taste fantastic, making them an easy prebiotic to add into your everyday diet.
Recipe idea: Try adding 2 small kiwifruit to your low FODMAP muesli and top with lactose free yoghurt.
6. Fennel bulb
Not sure what fennel bulb is? It is a highly aromatic vegetable that has a slightly sweet, and a little bit spicy anise flavour. Fennel bulb is easy to cook with and according to Monash University it contains high levels of prebiotics (5). Just watch your serving size as it is low FODMAP at ½ cup serves, and then becomes high FODMAP at 1 cup serves (5).
Recipe idea: Shred fennel bulb into your salad, braise it in the oven with chicken or fish, or puree it into soup!
7. Canned lentils
Lentils are a fantastic source of dietary fibre, protein, and prebiotics (11 12). While on the low FODMAP diet, canned lentils contain the least amount of FODMAPs and can be safely enjoyed in ½ cup serves (5)
Recipe idea: Try mixing canned lentils into soups, stews, or ground beef (mince) based dishes to increase fibre and protein.
8. Small serves of high FODMAP foods
Sweet corn, snow peas, and savoy cabbage are all high FODMAP foods that contain prebiotics (11). Luckily for us, these high FODMAP foods also have safe low FODMAP serving sizes (5). This means you can include a small serve of these foods in your low FODMAP elimination phase diet. Just remember to only have one safe serve of a high FODMAP food at a time.
Recipe ideas: Try mixing sweet corn into carrot & corn fritters, or add snow peas or savoy cabbage to your next stir-fry.
Final Thoughts
There are plenty of low FODMAP foods that contain prebiotics, so make sure you eat a wide range of low FODMAP foods each day to keep your gut bacteria happy!