Updated: Apr 15
We hear so much about fermented foods these days and how including them in our diet may help to support the gut microbiome. This microbiome is a diverse community of good bacteria inhabiting our intestines, so necessary for good health. These microflora create a protective lining in the intestines, guarding it against pathogens such as Salmonella and E. coli. The fermentation of food and beverages has been used by many traditional cultures for hundreds or thousands of years as a way to promote good health and to preserve food. Modern food production methods such as refrigeration, pasteurisation, and canning have caused a decline in fermented and probiotic-rich foods in our diet, and recent research shows us that the gut microbiome may in fact be supported by including fermented foods in our diet (1).
What is fermentation? There are two main types of fermentation; acid fermentation (such as lactic acid or acetic acid fermentation), and alcohol fermentation (where the sugars are converted into ethyl alcohol). For the health benefits mentioned in this article, I am referring to acid fermentation. Lactic acid fermentation is a metabolic process by which glucose and other six-carbon sugars such as sucrose and lactose, are converted into energy and lactate (or lactic acid), found in lacto-fermented foods. This refers to the Lactobacillus species of bacteria, so beneficial to our health. Lacto-fermentation is an anaerobic process (no oxygen is required), whereas acetic fermentation refers to starches, sugars and alcohols being converted into acid acid aerobically (with the presence of oxygen).
7 Health benefits of fermented foods and probiotics
A healthy microbiome may impact not only on our digestion but also on our skin health, mood, immunity, hormone balance, metabolism, and nutrient absorption (1).
1. Improved digestion Probiotic bacteria may have preventative and therapeutic effects against Irritable Bowel Syndrome (IBS), inflammatory Bowel Disease (IBD) and Helicobacter pylori infection (2) and studies have also shown improvements to intestinal permeability, otherwise known as leaky gut (3). 2. Healthy skin Many studies also show a link between leaky gut and skin conditions such as acne and rosacea, so we know that good gut health is directly related to healthy skin. 3. Improved mood One particular study showed that probiotic bacteria such as Lactobacillus rhamnosus may boost our mood by generating the neurotransmitter gamma-aminobutyric acid or GABA. This amino acid has a calming effect on the brain, and in particular on the areas in the brain that are over active in anxiety disorders and depression (4). Including fermented foods in the diet is thought to reduce social anxiety disorder. 4. Supports immunity Fermented foods may increase antibody production, reduce allergies, and stimulate immune cells, therefore strengthening the immune system (2). 5. Supports hormone balance As probiotic bacteria in fermented foods may benefit the gut lining, this in turn can help to balance your hormones. They may improve production of hormones such as insulin, leptin and ghrelin. 6. Increases metabolism By regulating the appetite and reducing sugar and refined carbohydrate cravings. 7. Increases nutrient absorption The probiotic bacteria in fermented foods are thought to synthesise and enhance the bioavailability of nutrients in our food. Fermentation with lactic acid bacteria increases folic acid, niacin (B3) and riboflavin (B2) in yoghurt and milk kefir (2). While you can take a probiotic supplement to have the same effect, it seems that fermented foods may be a better source long-term, and better still, you can easily and affordably make many of them yourself. ** Note that fermented foods may cause unwanted digestive symptoms for some people, depending on their current state of health. It may be better to address health conditions such as Candida albicans, or other gut related issues, before consuming fermented foods. Always monitor how you feel after consuming fermented foods and drinks, as what works for one person may not work for the next. Different types of fermented foods Different fermented food and drink products include:
miso (a Japanese seasoning paste made from fermented soy beans)
sauerkraut (German style cabbage)
kimchi (Korean style cabbage)
yoghurt (dairy or non-dairy)
kefir (milk or water based)
kombucha (made from sweet tea)
tempeh (Indonesian style fermented soy beans).
Other less known fermented food products include:
fermented vegetables or pickles
apple cider vinegar (with the mother)
natto (Japanese fermented soy beans)
beetroot kvass (a Russian fermented tonic)
Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):16050-5
Parvez, S. et al., 2006. Probiotics and their fermented food products are beneficial for health. Journal of Applied Microbiology, 100(6), pp.-1185
Singh, K.N.C. et al., 2014. Immune response and intestinal permeability in children with acute gastroenteritis treated with Lactobacillus rhamnosus GG: a randomized, double-blind, placebo-controlled trial. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 58(8), pp.1107–15. Available at: http://cid.oxfordjournals.org/content/58/8/1107 [Accessed September 2, 2015].–1185.
Messaoudi M, Lalonde R, Violle N, Javelot H, Desor D, Nejdi A, Bisson JF, Rougeot C, Pichelin M, Cazaubiel M, Cazaubiel JM. Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Br J Nutr. 2011 Mar;105(5):755-64.