Heard of zymology? Me either, until I started doing a bit of digging around on the benefits of including fermented foods regularly in the diet. Fermented foods are the result of zymology (or fermentation); the process of converting carbohydrates to alcohols and carbon dioxide or another organic acid, using bacteria, yeasts or a combination of the two. Fermented foods are a great source of prebiotics – organisms that promote the growth of good bacteria in the gut; and probiotics – live microorganisms that can colonise the gut and increase the numbers of good bacteria in the gut. Our gut bacteria are present in their trillions (!) and are the gatekeepers of our immune system and overall health. Most people are aware of probiotics present in yoghurt and while we are familiar with the terms acidophilus bifidus, some are a little less clear of other food sources of these organisms which play such an important role in our health. This is a very brief overview of the what, why, how and when of fermented foods and gut bacteria.
Gut health is important for overall health full stop, as 70% of body’s immune response originates from here. It’s not just about digestion, our gut is like our body’s armour shield against the environment, and the integrity of the gut lining is important in terms of protecting our system from proteins, toxins or foreign bodies that could trigger an immune response and cause inflammation. Children get their first exposure to immune boosting bacteria when they are born vaginally; in fact research shows that children who are born via caesarean have lower levels of good gut bacteria and are at higher risk of obesity, allergies and the development of chronic conditions later in life as their immune system doesn’t have the right bacteria to evoke an appropriate immune reaction.
Gut bacteria are responsible for breaking down compounds in food that could be harmful (carcinogens), synthesising b-vitamins (biotin, folate) and vitamin K, and help absorb minerals such as calcium, magnesium and iron. They also convert non-digestible carbohydrate (CHO) to short chain fatty acids (SCFA) acetate, propionate and butyrate, which provides energy and are beneficial to lining of the gut by stimulating the growth of cells that form the inner lining of the colon. In addition, butyrate has anti-inflammatory effects that can increase insulin sensitivity and may be useful in treating digestive-related conditions such as irritable bowel syndrome (IBS) and Crohns disease.
The inflammation that results from an imbalance of bacteria in the gut may contribute to development of many chronic conditions – both physical and mental health. Often people think that problems in the gut are evident only with digestive issues. Not so. When this imbalance leads to the intestinal tract becoming permeable, substances leak into our bloodstream and trigger an immune reaction – this contributes to the development of a range of conditions from autoimmune disease, to depression, obesity, skin disease. Leaky gut isn’t always obvious in terms of gut symptoms – but can be skin rashes (eczema, psoriasis) , anxiety, fatigue, joint pain, acne and fibromyalgia.
Lifestyle factors contributing to an imbalance of gut bacteria include the use of antiobiotics and other medications such as ibuprofen, a poor diet that is high in processed refined carbohydrate and industrial seed oils and low in nutrients; chronic stress (physical, mental and environmental), chronic infections and small intestinal bacteria overgrowth (SIBO). This is an overgrowth of bacteria in small intestine (instead of colon, where it belongs) – causing malabsorption of proteins, fats, fat soluble vitamins, b-vitamins and other micronutrients important for immune health.
So why fermented products? Research has shown their usefulness in improving intestinal tract health, enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients and decreasing the prevalence of allergy in susceptible individuals due to the availability of prebiotics and probiotics. Some common food sources are listed below. This isn’t an exhaustive list, but some found in the health food store or (in some instances) your supermarket include:
- Water kefir
- Dairy kefir
- Sauerkraut (raw, in refrigerated section – not Edgells canned variety)
- Kim chi
- Yoghurt high in cultures
- Raw apple cider vinegar
- Fermentable fibres in foods: fruits, vege, starches, nuts, seeds: this helps maintain the good bacteria that help produce SCFA.
Fermented vegetables aren’t for everyone, however. If you have a histamine intolerance (due to a reduction in enzymes responsible for breaking down histamine) then it’s best to avoid these. Fermented foods contain histamine, and the accumulation of this in the gut can trigger an immune reaction and mimic allergic reactions.
Those with an inability to digest foods containing FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) intolerance – an inability to break down these carbohydrate types lactose, fructose in fruit, coconut products, sweeteners and sugar alcohols (found in sugar free chewing gum). In addition, it’s best to avoid these if you have severe gut dysbiosis, until there is a better balance of good bacteria.
An easy way to add these into your diet would be to start the day with a tablespoon of raw apple cider vinegar in water, add a tablespoon or two of fermented vegetables to lunch and/or dinner, and for people including dairy in their diet, consume yoghurt that has live cultures or is a kefir-style yoghurt. While you can get yoghurt that contains sugar along with probiotics, it makes little sense to me to consume this as a way to promote good gut bacteria, given that sugar can trigger the growth of the bad guys. If you’re new to the idea of fermented food, it is a good idea to start adding these in slowly – perhaps roll with one of the ideas above and build on that. Too much can trigger further gut distress, particularly if you’ve got some nasties taking up space in your gut.
In addition, if you do have IBS or inflammatory bowel disorder, non-starchy vegetables high in insoluble fibre can further irritate an inflamed gut. These include: Greens, whole peas, (any peas), green beans, kernel corn, bell peppers, eggplant, celery, onions, (and the family), brassica (cabbage, Brussels, broccoli, cauliflower). Take care when eating these and ensure you cook them thoroughly to aid digestion, and don’t eat these on an empty stomach. Including vegetables that are higher in soluble fibre (ie carrots, pumpkin, potatoes, kumara, parsnips swede and beetroot) can also be useful.
As with anything, a whole food diet is a great foundation for healthy gut bacteria – and no amount of sauerkraut will offset the potential damage of a poor diet devoid nutrients. So fight the good fight and clean up your diet first and foremost.