What are prebiotics and probiotics?
Fermentation as a preparation method has been around for centuries. Fermentation occurs when beneficial bacteria and yeast break down the natural sugars in food, producing lactic acid, enzymes and probiotics in the process. This increases the nutrient content, beneficial bacteria and makes it more digestible (for example, the gluten content in sourdough bread is more tolerated because it has been fermented, this excludes coeliacs). This fermentation process is important for our gut health as it increases our gut diversity. The gut microbiome plays a central role in metabolic, immune, and neurological function, when gut bacteria ferment indigestible fibres from dietary fibre rich foods, they produce short-chain fatty acids, compounds known for their anti-inflammatory properties. Research has found that reduced microbial diversity and lower SCFA production are linked to disturbances in mood. One systematic review of 15 studies found a strong link between reduced microbial diversity and mental disorders such as depression, anxiety and bipolar disorder.
A well-known analogy is to think of your gut like a garden, an ecosystem that needs to be taken care of in order to thrive and grow the right plants and to decrease the risk of having too weeds overtaking. The soil is your gut lining, it protects you, absorbs nutrients and keeps everything moving smoothly. The good and bad bugs in the garden are your gut bacteria, we need a balance of both to thrive, these microbes help digest foods, produce vitamins and support our mood. Water and sun are our fibre and hydration, just like plants need nourishment from sun and the rain, the gut needs fibre from plants and adequate amounts of water to keep things moving properly and not get stuck. Fertilisers are the prebiotic rich foods, these feed the probiotics (good bacteria) found in the gut to keep a good balance within. Weeds growing in the garden represent sugar, stress, alcohol, ultra processed foods, these can throw the gut off balance and cause inflammation, it’s okay to have weeds but we need the right support to not let them overpower the good gut bacteria. Taking care of our inner environment is key to a glowing external environment.
Before diving into fermented foods, it’s important to know the difference between prebiotics and probiotics.
What are prebiotics?
A type of fibre that cannot be digested by the body. These feed the probiotics. When we eat and break down the fibre, this forms short-chain fatty acids that are absorbed into our bloodstream and contribute to anti-inflammatory functions.
Prebiotic food sources
- Garlic, onions, leeks
- Asparagus
- Banana
- Seaweed
- Most fruits + vegetables
- Beans + whole grains such as wheat, oats and barley
What are probiotics?
Bacteria that live in the gut and benefit our body. These live microbes, including bacteria and yeast, are found in fermented foods and supplements.
Probiotic food sources
- Kombucha
- Kefir
- Pickled vegetables (i.e. pickled cornichon, onions)
- Sauerkraut
- Tempeh
- Kimchi
- Miso
- Coconut yogurt with live active culture
For most people, the first step to increasing your gut microbiome isn’t through supplementation, you can take a food-first approach to build that diversity. Fermented foods are the most well-known gut-friendly foods, full of beneficial bacteria from their live cultures, and these probiotics are fed by the prebiotic foods listed above.
But not all "fermented" products on shelves are equal, here’s what to look out for when choosing them:
- Watch out for pasteurised or shelf-stable products (they don’t always contain live bacteria). Choose unpasteurised versions or check the fridge section
- Look for “naturally fermented” on the label
- Check for “live active cultures” on the label
- If vinegar is the first ingredient on the jar of pickles, they’ve been pickled (which is great) rather than fermented. Ferments are just salt and water
- Look out for flavoured kombucha. Some kombuchas have a lot of added sugar which can reduce the fermented benefits. Check for “raw” or “unpasteurised”.
Beyond choosing the right fermented foods, here are a few other habits to support an optimal environment for increasing your gut diversity:
Increase daily fibre whole foods intake
- Eat the rainbow: include a wide variety of plant foods
- Reduce intake of processed foods including refined fats and sugars
- Consume fermented foods
- Avoid high consumption of alcohol and smoking
- Avoid over-usage of antibiotics and medications
- Maintain a constant sleep routine
- Daily exercise routine
A few tips to increasing your gut diversity this week with fermented foods:
- Start this week by including 1–2 tbsp sauerkraut daily in your meals
- Include at least 2 fully plant-based meals this week
- Add miso paste into your sauces
- Alternate your current yogurt to coconut yogurt (with live bacteria)
- Include apple cider vinegar with “the mother” in your salad dressings
A note on individual tolerance: The goal is to include a variety of fermented foods consistently as part of a balanced diet. However, tolerance is highly individual. Some people may experience symptoms or need to limit certain fermented foods due to individual health conditions or sensitivities, such as suspected histamine intolerance or SIBO. If fermented foods trigger symptoms or you have a health condition, it’s a good idea to speak with a nutritionist to find what works best for you!