Fermented foods and beverages are getting increasingly popular. you’ll now find kombucha on tap in bars, sour bread in cafes and more sorts of yoghurt, sauerkraut and kimchi in your local supermarket.
But what are the guts health benefits and will you be including them in your diet? this is often an inventory of fermented foods, which are foods produced or preserved by the action of microorganisms. during this context,
fermentation typically refers to the fermentation of sugar to alcohol using yeast, but other fermentation processes involve the utilization of bacteria like lactobacillus, including the making of foods like yoghurt and sauerkraut. The science of fermentation is understood as zymology.
Many pickled or soured foods are fermented as a part of the pickling or souring process, but many are simply processed with brine, vinegar, or another acid like juice.
Fermented foods are a part of the human diet for hundreds of years, and were initially produced as how to preserve foods, improve flavour and eliminate food toxins. Today, more people are turning to those foods for his or her potential health benefits. More read
What are fermented foods?
Fermented foods are foods and beverages that have undergone controlled microbial growth and fermentation.
Fermentation is an anaerobic process during which microorganisms like yeast and bacteria break down food components (e.g. sugars like glucose) into other products (e.g. organic acids, gases or alcohol). this provides fermented foods with their unique and desirable taste, aroma, texture and appearance. Read Holistic medicine
There are thousands of various sorts of fermented foods, including:
cultured milk and yoghurt
- fermented sausage.
Most foods are often fermented from whole foods like vegetables, fruits, cereals, dairy, meat, fish, eggs, legumes, nuts and seeds.
While these foods are nutritious in their original form, through fermentation, they need the potential to hold additional health benefits – especially once they contain probiotics and prebiotics. More Read
What are probiotics?
Many people know probiotics as ‘good’ or ‘friendly’ bacteria for the gut, with Lactobacillus and Bifidobacterium being the foremost well-known. Probiotics are live microorganisms or bacteria that provide a health benefit to the physical body 4, 5. Read Apple Cider
Experts believe that the majority of strains from commonly studied species, like Lactobacillus and Bifidobacterium, benefit the gut by creating a more favourable gut environment. They also agreed that probiotics support a healthy system, however, some strains could also be simpler than others.
Several other benefits like supporting organ health (e.g. lungs, reproductive, skin) and mood are promising, but there’s not enough evidence to mention that each one probiotic have these effect. Read EHR
Many fermented foods contain probiotics because they’re added or they naturally occur within the food. for instance, Lactobacilli maybe a probiotic strain that’s commonly found in yoghurt and naturally lives on the surface of some foods like vegetables and fruit.
this suggests that not all fermented foods contain probiotics, especially many commercially produced foods that are pasteurized, which kills any bacteria (along with their associated health benefits). More Read
What are the advantages of fermented foods?
Fermented foods have historically been valued for his or her improved time period and unique taste, aroma, texture, and appearance. They also allow us to consume otherwise inedible foods. for instance, table olives must be fermented so as to get rid of their bitter-tasting phenolic compounds.
Many health benefits are related to fermented foods, including reduced risk of disorder, high vital signs, diabetes, obesity, and inflammation. they need also been linked to raised weight management, better mood and brain activity, increased bone health,
and better recovery after exercise 1, 3. When watching heart health, probiotics may help to decrease total and LDL (LDL) cholesterol however the evidence for this is often still very limited 8.
One explanation for all of those effects is that the production of bioactive peptides, vitamins, and other compounds produced by the microorganisms involved in fermentation and have key roles within the body, like blood health, nerve function, and immunity. Read about Health
It’s important to recollect that these health benefits are likely hooked into the sort of fermented food and microorganisms involved. for instance, yogurt consumption has been related to a reduced risk of type 2 diabetes 9-11, while fermented milk that contains Lactobacillus has been related to reduced muscle soreness 12.
How am i able to eat more fermented foods?
Although fermented foods may sound fancy, the practice of fermentation is really simple and affordable. It only requires a couple of ingredients and when done reception, can prevent tons of cash while adding variety, new flavors, and interesting textures to your diet.
Vegetables like cabbage, beetroot, radish, turnip, and carrots are a number of the simplest foods to ferment reception because the bacteria living on the surface do the fermenting for you.
Try making your own sauerkraut, kimchi, and pickled seasonal vegetables, including prebiotic-rich foods like onion and garlic to feature flavor and additional health benefits.
Kimchi – fermented cabbage recipe
Pickled vegetable recipe
This is an excellent thanks to experiencing the advantages of fermented foods while including more vegetables in your diet.
Despite fermented foods being nutritious foods, there’s no single food that improves our heart health – it’s our overall diet.
Fermented foods are best eaten within the context of a heart-healthy eating pattern that emphasizes vegetables, fruit, whole grains in situ of refined grains, legumes, nuts, seeds, and oily fish.
The sourdough starter culture is produced through the fermentation of flour by carboxylic acid bacteria and yeasts, that originate from the flour and surrounding environment. Making the sourdough starter takes on an average of seven days and involves replenishing the microbes with fresh flour and water daily.
Once the starter is prepared, a little portion is added to the sourdough base ingredients to initiate the sourdough fermentation process—this method is usually mentioned as “backslapping”.
Unlike standard bread, which is produced through a rapid yeast-only fermentation process, the symbiotic sourdough fermentation of both bacteria and yeast is assumed to enhance bread quality, including texture, flavor, nutritional content, and shelf-life, and replace additives.
During fermentation, microbial and enzymatic-led conversions of cereal carbohydrates, proteins, lipids, and phenolic compounds occur. The microorganisms and enzymes’ activity are interlinked; for instance, carboxylic acid bacteria end in a pH reduction, modulating the activity of cereal enzymes and solubility of substrates (e.g., gluten), and successively the enzymes can provide substrates to permit the expansion of microorganisms.
The microbial content of the sourdough starter depends on the normal practices used and, therefore, not only the taste and texture, but the nutritional profile of the ultimate product can vary considerably.
generally, several species within the Lactobacillus, Leuconostoc, Weissella, Pediococcus, and Streptococcus genera are identified in sourdough starters. Lactobacillus species are the foremost prevalent, and Lactobacillus sanfran siscensis may be a key bacterium isolated from most starters.
baker’s yeast is that the most abundant yeast species, followed by Candida Milleri, C. Humilis, Saccharomyces exiguous, and Issatchenkia Orientalis. Only limited data exist on the microbial composition of sour bread, likely thanks to the impact of warmth during baking, with just one study showing a gene copy number of seven to 10 log gene copies/gram of sour bread.
The mechanisms through which sour bread may confer health benefits are primarily through the impact that the sourdough process has on the nutritional content of bread. for instance, the sourdough process can lower the bread’s content of non-digestible oligosaccharides fructans and raffinose (types of FODMAPs), leading to the bread being better tolerated by patients with IBS.
this alteration within the carbohydrate content occurs thanks to the degradation of oligosaccharides by the sourdough microorganisms, especially the yeasts baker’s yeast, and Kluyveromyces Marian.
Sourdough and its constituent microorganisms have also been suggested to exhibit anti-microbial, anti-hypertensive, and cholesterol-lowering properties, however, these are supported in vitro studies examining the impact of sourdough-extracted bacteria, instead of baked sour bread
Sourdough Bread in Gastrointestinal Health and Disease
Several studies have examined the impact of sour bread on gastrointestinal function and disorders. during a double-blind, cross-over RCT, 17 healthy adults were randomized to consume one meal of two sourdough croissants or 2 brewer’s yeast croissants, followed by resonance imaging analysis of gastric emptying.
the entire gastric volume was significantly reduced by 11% and hydrogen production by 30% following sourdough croissants compared to brewer’s yeast croissants ]. Abdominal discomfort, bloating and nausea were significantly milder, suggesting sourdough croissants are better tolerated than brewer’s yeast croissants.
additionally, a really small randomized cross-over trial of seven participants reporting minor gastrointestinal symptoms showed a significantly different exhaled breath volatile compound profile following sourdough bread compared to wheat bread enriched with bioprocesses rye bran, however, the impact on gastrointestinal symptoms wasn’t measured. this means that the potential health effects of sourdough bread may indeed be mediated by the gut microbiota.
Traditional kefir, which originates from the Caucasus, maybe a fermented milk drink with a creamy texture, sour taste and subtle effervescence. it’s produced by adding a starter culture termed “kefir grains” to exploit.
Kefir grains contain symbiotic lactose-fermenting yeasts (e.g., Kluyveromyces Maximus) and non-lactose fermenting yeasts (e.g., baker’s yeast, Saccharomyces uni sports), also as lactic and ethanoic acid-producing bacteria, housed within a polysaccharide and protein matrix called kefiran.
Lactic acids, Flavour-generating components (e.g., acetaldehyde), ethanol and CO2 are all by-products of fermentation and contribute to the organoleptic properties of kefir.
A dairy-free version of kefir also exists, called water kefir, which may be a fermented beverage made from water, sugar and water kefir grains, which contains bacteria and yeasts, albeit different to the normal kefir starter cultures. there’s very limited evidence on water kefir and, therefore, this section focuses on traditional kefir only.
A wide range of microbial species is identified in kefir grains, commonly including Lactobacillus Brevis, L. Paracasei, L. Helveticus, L. Kefiranofaciens, L. Plantarum, L. kefir, Lactococcus Lactis, Streptococcus thermophiles, Acetobacter Lovaniensis, Acetobacter Orientalis, baker’s yeast, S. uni sports, Candida Kefyr, Kluyveromyces Maximus and Leuconostoc mesenteron ides.
Following fermentation, the microbial composition of kefir may change. for instance, although not a predominant Lactobacillus species within the kefir grain starter culture, L. kefir can represent 80% of all Lactobacillus species within the final fermented beverage.
The Food and Agriculture Organisation (FAO) and therefore the World Health Organisation (WHO) suggest that kefir grains should contain a minimum of 107 colony forming units (CFU)/g microorganisms and the final product should contain a minimum of 104 CFU/g of yeast.
Several in vitro studies have investigated kefir’s antimicrobial activity, which is attributed to competition with pathogens for available nutrients, also because of the production of organic acids, bacteriocins, CO2, peroxide, ethanol and diacetyl.
In vitro studies have shown that kefir exhibits antimicrobial activity against Candida albicans, typhoid bacillus, Salmonella Enterica, Shigella sonnei, Escherichia coli, Bacillus subtilis, Enterococcus Faecalis and Staphylococcus aureus.
Fermentation-derived bioactive peptides produced from casein are shown to stimulate the system in animal models, while kefiran reduced ovalbumin-induced cytokine production during a murine asthma model. In vitro and animal studies have also suggested potential anti-oxidative, anti-hypertensive, anti-carcinogenic and cholesterol-and glucose-lowering effects of kefir.
The impact of kefir and its constituent microorganisms on the gut microbiota has been investigated in several in vitro, animal and human studies.
Although not yet confirmed in vivo, several strains isolated from kefir are shown to stick to human enterocyte-like Caco-2 cells, indicating a possible ability to colonise the human gut.
Kefir, or its constituent strains, have also been shown to possess a substantial impact on the gut microbiota population with increases in Lactobacillus, Lactococcus and Bifidobacterium concentrations, and reductions in Proteobacteria and Enterobacteriaceae concentrations, being demonstrated in numerous animal studies.
Furthermore, one study found higher concentrations of Firmicutes, Bacteroidetes and Prevotella, also as a better stool weight and stool water, in mice, administered Lactobacillus Kefira notations (but not kefir per se), a standard strain found in kefir grains, compared to regulate. additionally,
a study showed that kefiran increased stool weight and moisture in rats, during a dose-responsive manner, compared to regulate, suggesting a possible beneficial effect in constipation.
The abundance of yeasts within the alimentary canal is additionally altered following kefir consumption; a study during a high-fat diet-induced obese mouse model showed that those that ingested 0.2 mL kefir had a significantly greater number of stool total yeasts and Candida kefir compared to regulate mice.
In humans, a study in 45 people with inflammatory bowel disease showed that a kefir-specific strain, Lactobacillus kefir, was identified in most participants’ faeces 4 weeks following 800 mL/day kefir consumption, and a big increase in total stool Lactobacillus abundance was found compared to regulate (no kefir) in patients with Crohn’s disease.
Kefir in Gastrointestinal Health and Disease
Several studies are administered in humans investigating the effect of kefir consumption on gastrointestinal function and dysfunction. Kefir has been suggested to be tolerated by people with lactose malabsorption since it contains β-galactosidase expressing bacteria (e.g.,
Kluyveromyces maximum), which hydrolyses lactose, thus reducing lactose concentrations within the drink. Kefir contains 60% more β-galactosidase than plain yoghurt, while a 30% reduction in lactose content has been shown in kefir compared with unfermented milk.
Despite reportedly greater β-galactosidase concentrations in kefir than yoghurt, a little cross-over randomised controlled trial (RCT) in 15 people with lactose malabsorption showed that although kefir produced a significantly lower breath hydrogen concentration compared to exploit.
it had been similar following kefir and plain yoghurt, suggesting that kefir and plain yoghurt improved lactose digestion to an identical degree Kefir also led to a significantly lower flatulence severity compared to exploit, but no differences were seen for flatulence frequency, abdominal pain and diarrhoea.
Overall, this study suggests kefir leads to lower flatulence severity than milk and is also tolerated as yoghurt, in people with lactose malabsorption.
Several non-randomised studies have also explored the impact of kefir in constipation (Table 2). A non-randomised cross-over study in 42 hospitalised patients with constipation and mental and physical disabilities showed that 6 g of lyophilized kefir had no impact on laxative use, stool consistency and stool volume compared to regulate dry milk.
however, the number of patients not requiring any laxatives was higher 12 weeks following the kefir intervention compared to baseline (Table 2). Another small non-randomised, uncontrolled trial in 20 people with functional constipation showed that 500 MLS of kefir for 4 weeks significantly increased stool frequency, improved bowel satisfaction score and reduced gut transit time compared to baseline.
Considering the tiny sample and limitations in study design (difference in kefir form, no randomisation, uncontrolled, limited use of validated procedures), further high-quality trials are required to determine the impact of kefir on constipation.
In summary, there’s only very limited evidence on the effectiveness of most fermented foods in gastrointestinal health, with the bulk of studies being of inferiority.
Kefir is that the fermented food most ordinarily investigated in terms of its impact on gastrointestinal health, with evidence suggesting it’s going to be beneficial for lactose malabsorption and H. pylori eradication.
No human studies are conducted on the impact of kombucha, tempeh, and kimchi on gastrointestinal health. it’s worth noting the problem in undertaking and replicating fermented food studies given the many variabilities of cultures and ingredients present even within food categories, which can partly explain heterogeneous findings.
To conclude, there’s insufficient evidence to work out the impact of fermented foods on gastrointestinal health and disease.