Fermented foods have been in the spotlight recently as more and more consumers learn about their various probiotic health benefits. Fermentation is a process where natural, microorganisms such as yeast and bacteria break down the starches and sugars in foods. It is an ancient technique that is believed to have been developed 9000 years ago to help our ancestors preserve food, as well as improve flavour and reduce the risk of food poisoning. It's also been found to offer an array of health benefits including improved immunity, better digestion, and weight loss. This is mainly due to fermentation promoting the growth of beneficial bacteria, also known as probiotics (1). Key benefits of fermented foods: Digestive health Fermented foods can have an immense benefit on gut health primarily due to their high levels of probiotics. Research has shown us that probiotics can lessen the uncomfortable symptoms of some common digestive disorders such as irritable bowel syndrome (IBS) (2). A 2007 study that focused on 274 patients who suffered from IBS found that consuming 125 grams of a yogurt-like fermented milk everyday improved their IBS symptoms, including reducing bloating and improving stool frequency (3). Other studies have discovered that fermented foods may also lessen the severity of IBS symptoms including diarrhea, gas, and constipation (4, 5). Also, fermentation makes food easier to digest. It helps break down and destroy compounds called ‘antinutrients’ that can prevent us absorbing vitamins and minerals. These antinutrients (including phytates and lectins) are naturally found in many foods including nuts, seeds grains, and legumes (10). Immune health Firstly, many fermented foods are rich sources of vitamin C, zinc, and iron. These three micronutrients are proven to strengthen the immune system (8). Research has also demonstrated that consuming probiotic rich foods may also help people to recover faster when ill. This is because bacteria that live in the gut have a significant impact on the immune system and can even reduce the risk of infections such as the common cold (6, 7). Furthermore, recent studies have shown us that when there are changes to the bacterial communities in a person’s gastrointestinal system, this can lead to increased inflammation and immune imbalance. Some researchers believe bacteria changes in the gut are a major reason for the rise in many autoimmune diseases around the world (8). Weight loss and metabolic health Some research has shown a link between specific probiotic strains such as Lactobacillus rhamnosus and Lactobacillus gasseri, with weight loss and reduced abdominal fat (11, 12). A 2012 study showed that Lactobacillus rhamnosus CGMCC1.3724 (LPR) supplementation helped obese women to achieve sustainable weight loss (11). In 2013 research demonstrated that consumption of the probiotic strain Lactobacillus gasseri (LG2055), had a significant lowering effect on abdominal adiposity (fat) (12). Common fermented foods: The list of fermented foods is extremely long but some common fermented foods that are popular today include sauerkraut, miso, kefir, kimchi, tempeh, probiotic yogurt and kombucha. There are no official guidelines telling us how often to consume fermented foods, however most experts agree that including 1-3 servings in your everyday diet is going to be beneficial to health (1). References: 1. Bell V, Ferrão J & Fernandes T, (2017). Nutritional Guidelines and Fermented Food Frameworks. Foods;6(8):65. 2. Hoveyda N et al, (2009). Systematic review and meta-analysis: probiotics in the treatment of irritable bowel syndrome. BMC Gastroenterol; 9:15.3. Guyonnet D, Chassany O, Ducrotte P, Picard C, Mouret M, Mercier CH, Matuchansky C, (2007). Effect of a fermented milk containing Bifidobacterium animalis DN-173 010 on the health-related quality of life and symptoms in irritable bowel syndrome in adults in primary care: a multicentre, randomized, double-blind, controlled trial. Aliment Pharmacol Ther;26(3):475-86.4. Dimidi E, Christodoulides S, Fragkos KC, Scott SM, Whelan K, (2014). The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr;100(4):1075-84.5. Guarino A, Lo Vecchio A, Canani RB, (2009). Probiotics as prevention and treatment for diarrhea. Curr Opin Gastroenterol;25(1):18-23.6. King S, Glanville J, Sanders ME, Fitzgerald A, Varley D, (2014). Effectiveness of probiotics on the duration of illness in healthy children and adults who develop common acute respiratory infectious conditions: a systematic review and meta-analysis. Br J Nutr;112(1):41-54.7. Guillemard E, Tondu F, Lacoin F, Schrezenmeir J, (2010). Consumption of a fermented dairy product containing the probiotic Lactobacillus casei DN-114001 reduces the duration of respiratory infections in the elderly in a randomised controlled trial. Br J Nutr;103(1):58-68.8. Wintergerst ES, Maggini S, Hornig DH, (2007). Contribution of selected vitamins and trace elements to immune function. Ann Nutr Metab;51(4):301-23.9. Belkaid Y, Hand TW, (2014). Role of the microbiota in immunity and inflammation. Cell;157(1):121-141. 10. Gupta RK, Gangoliya SS, Singh NK, (2015). Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. J Food Sci Technol;52(2):676-84.11. Sanchez M, (2014). Effect of Lactobacillus rhamnosus CGMCC1.3724 supplementation on weight loss and maintenance in obese men and women. Br J Nutr;111(8):1507-19. 12. Kadooka Y et al, (2013). Effect of Lactobacillus gasseri SBT2055 in fermented milk on abdominal adiposity in adults in a randomised controlled trial. Br J Nutr;110(9):1696-703.