Long consumed by humans, fermented food has been a dietary staple for thousands of years.
But why has fermented food always enjoyed such popularity?
Was it just a way to preserve food before refrigeration was available, or is there more to it than that?
This article will take a look at the health benefits of fermented food and how it may affect our gut health.
What Are Fermented Foods?
Fermentation of food is for preservation and to encourage the growth of beneficial enzymes and bacteria.
One of the most traditional ways of fermenting food is to use the lacto-fermentation process. In very simple terms; the process starts by soaking vegetables in either water or salted water.
Soon after, harmful bacteria present on the vegetable die while the good bacteria survive.
Following this, the good bacteria convert the natural sugars present in vegetables into lactic acid. As a result, lactic acid levels rise and preserve the food.
This process has many benefits; it helps improve both the nutrient profile and digestibility of the food. In addition to this, fermentation creates good bacteria and enzymes that benefit our health, preserve the food, and create new flavors.
All our ancestors had these foods in their diet; Europeans consumed cheese, sauerkraut, wine, and yogurt. In Asia; kimchi, natto, and various fermented fish recipes remain popular after centuries of consumption.
The Lost Tradition of Fermented Food (in the West)
Countries in the far east such as Japan and Korea always experience long, scorching summers and bitterly cold winters.
Fermentation was necessary to preserve their fresh produce. Vegetables would quickly go bad in summer, and die in winter.
Of course, Korea and Japan are two of the biggest economies in the world. They have access to modern consumer electronics. Every house has a refrigerator and they no longer need cultured vegetables.
But they still ferment their food, and they are still enjoying the health benefits of eating fermented food every single day.
1East vs West
In Western countries, it is very different.
For one thing, we tend to use canning processes and chemical preservatives to keep our food fresh.
Our way of preserving food puts convenience first, but when it comes to health, it doesn’t hold a candle to traditional methods.
Several studies over recent years have also linked chemical preservatives to allergic reactions, asthma, intestinal damage, and many other health problems (7).
Unfortunately, though, the majority of consumers have a desire to continue buying packaged foodstuffs from supermarkets.
Seemingly, they value convenience above all despite being aware of the potential dangers (8).
As a society, we have indeed lost the art of fermentation. Worse still, we tend to indulge in lifestyle behaviors that are detrimental to our gut health.
5 Health Benefits of Eating Fermented Food
We are only recently re-discovering the importance of gut health and probiotics, and at this stage no-one can really say how important (or not) they might be.
However, here is a list showing five health benefits of fermented foods that we do know of.
2Fermented Foods Improve Gut Health and Microbiota Balance
Our gut is an integral yet overlooked predictor of overall health.
I’m sure you know that what you eat plays an important role in your health, but in addition to that; you can only get nutrients from foods that you can actually digest.
If you’re not digesting food properly, then you can be eating a healthy diet and it won’t matter.
This is where fermented foods are beneficial.
When you consume fermented foods, beneficial probiotics (otherwise known as ‘good bacteria’) enter your digestive system.
Bacteria such as lactobacillus and bifidobacterium both produce lactic acid and support the optimal breakdown of food during digestion. The good bacteria from fermented foods help us to digest food, destroy bad bacteria, and aid in the manufacture of vitamins (13).
Additionally, the ratio between good and bad bacteria in our gut play a role in the development (or prevention) of many health issues.
The research in this area is very raw but it’s a fast emerging field.
3Fermented Foods and Diabetes Risk
Fermented foods have a connection to diabetes in several ways.
For example, fermented foods contain lacto-fermented carbohydrate, making them pre-digested. This makes them much less taxing to the pancreas and overall digestive system.
Additionally, fermented foods contribute to a healthy gut microbiota.
On this note, there is some interesting research in regard to gut health and type 2 diabetes.
- A 2012 study analyzed gut microbial DNA from 345 individuals and found that each participant with type 2 diabetes had an imbalanced gut flora, a decrease in beneficial bacteria and an increase in ‘opportunistic pathogens’ (17).
- A study back in 2010 investigated this by analyzing 36 adult males, 18 of whom had type 2 diabetes. There was a richer variety of beneficial bacteria in the non-diabetics across the group (18).
Further research suggests that intestinal microbiota plays a large role in the prevention of metabolic dysfunction in humans.
We can see the same negative changes in bacterial diversity in both obesity and diabetes. Evidence shows that feeding a high-sugar western style diet for 8 weeks creates an altered gut microbiota (19, 20).
The gut microbiota may also play an important role in preventing diabetes-related ‘complications’ such as foot ulcers, atherosclerosis, and diabetic retinopathy. This is suspected to be through the further development of T2D as a result of an imbalanced microbiota’s contribution to inflammatory component (21).
It is worth remembering that refined carbohydrates and simple sugars have strong links to both T2D and an imbalanced gut flora.
Foods that contribute to a healthy microbiome are fibrous pre-biotic vegetables that feed good bacteria; these include foods like leafy greens, garlic, onions, carrots, leeks and chives (22).
5Fermented Foods Increase Resistance to Harmful Bacteria
Fermented food consumption leads to greater antimicrobial activity in the gut.
This is through the production of beneficial microbes that defend against pathogens and bad bacteria.
Some of these microbes are even capable of removing procarcinogens and alleviating allergy symptoms (23).
As well as this individual impact microbes make, they also stimulate the immune system.
6Fermented Foods and Mental Health
You might not imagine the link between fermented food and your mental health, but recent studies show a strong connection.
Lack of dietary fermented foods has links to:
- Increased levels of anxiety
- Difficulty processing emotions
- Social withdrawal
A healthy gut microbiome is essential for optimal well-being and your mental health is no exception.
There are a wealth of studies in this area and some recent research indicates that:
- Higher frequency of fermented food consumption is associated with less anxiety (27).
- The probiotic Bifidobacterium decreases anxiety-like behavior in mice (28).
- Lactobacillus bacteria appears to have an effect on the central nervous system (CNS) and reduces stress hormones, lessening the effect of anxiety and depression (29).
- In several controlled studies, groups supplementing probiotics had improvements in anxiety and depression versus placebo. Additionally, stress hormones were lower (30).
- In a randomized, double-blind controlled study, participants took lactobacillus or a placebo for two months. The results showed that in those taking the lactobacillus, they had a much higher level of the bacteria in their gut. They also had a significant decrease in anxiety compared to the placebo (31).
- A study last year took fecal samples from 46 patients with major depressive disorder (MDD) and 29 from healthy individuals. The samples from those with MDD had a higher amount of harmful bacteria and a lower amount of beneficial bacteria (32).
7Fermented Foods and Obesity
A gut microbiome with an imbalance of good and bad bacteria has strong associations with obesity.
Extensive research exists in this area and much of it shows the beneficial impacts of fermented food.
The staple food of Korea, Kimchi, comes in two varieties; fresh and fermented.
Both are popular, but in controlled studies comparing the two, fermented kimchi showed a much more significant effect on weight reduction and decreasing body fat percentage (33).
A 2015 study investigated the influence of the gut microbiota on obesity, metabolic syndrome, and gastrointestinal disease.
The diagram below shows how the authors of this study differentiated between altered microbiome states and health impacts.
The study presented findings explaining how colonies of beneficial gut bacteria are protective against obesity.
Additionally, they found evidence linking early childhood exposure to antibiotics with obesity. It’s common knowledge that antibiotics adversely impact the population of our microbiome (34).
Another study that investigated the differences between ‘obese’ and ‘lean’ microbiomes found that there were clear differences between the two.
The ‘obese microbiome’ had an increased capacity to harvest energy from food (35).
Best Fermented Foods
Now that you know the benefits of fermented foods, perhaps you’re wondering how to incorporate them into your diet?
Here is a list of some fermented foods that may help you.
Maybe the world was blind to kimchi 5 years or so ago. But these days, almost everyone has heard of the Korean fermented cabbage and rightly so – it tastes great and improves your health.
Kimchi is a fermented vegetable. To make it, cabbage is seasoned with fish sauce, red pepper flakes, garlic, ginger and salt, and then left to ferment.
Kimchi Health Benefits
Kimchi is regarded as having anti-obesity, anticancer, probiotic and antioxidative properties.
The effects of kimchi can be attributed to the wide range of beneficial compounds created by the fermentation of garlic, ginger, fish, and cabbage (36).
This traditional German food is known and loved throughout Europe.
Similar to Kimchi, the major ingredient of sauerkraut is cabbage. But that’s where the similarities end.
On the positive side, mking sauerkraut is much easier. The cabbage is simply layered, covered in salt, and then left to ferment.
Sauerkraut Health Benefits
Sauerkraut is rich in vitamins A, C, K and B-vitamins, as well as a wide range of essential minerals (37).
Regular consumption of sauerkraut has links to many health benefits; research is ongoing into the impact sauerkraut has on reduced incidence of cancer and allergic reactions.
Many researchers believe fermented cabbage is healthier than raw or cooked cabbage, and it contains an anti-cancer compound, but more research is needed (38).
Who doesn’t love cheese? If you’ve tried raw cheese you’ll appreciate the fuller flavor and probiotic content.
What is Raw Cheese?
Raw cheese is simply cheese that hasn’t been pasteurized.
During the pasteurization process, dairy is exposed to high heat which kills beneficial bacterial strains and enzymes contained in the milk/cheese.
Raw Cheese Health Benefits
Cheese contains a range of beneficial bacterias that high temperature destroys when heated to 47/48°C, hence raw cheese retains this benefit while pasteurized cheese does not (39).
Yogurt is one of those rare foods that almost everyone agrees about. It has numerous documented health benefits.
What is Yogurt?
Yogurt is a dairy food prepared from fermented milk. Beneficial bacterial strains added to the milk start the fermentation process.
Yogurt comes in several varieties; ideally, choose plain yogurt and stay away from the low-fat versions full of sugar.
Yogurt Health Benefits
Yogurt is particularly high in calcium and phosphorus and contains beneficial probiotics.
Based on a survey of 41,436 men, yogurt was consistently and inversely associated with type 2 diabetes risk (40).
Additionally, in a prospective study of 45,214 volunteers, yogurt consumption showed a significant inverse association with colorectal cancer (41).
Some people dismiss the importance of fermented foods, viewing them as an unnecessary addition to our diet.
However, the reliance on fermented foods by our ancestors around the world hints at their historical value.
Our understanding of the gut microbiome is only in its infancy and new information is rapidly emerging.
But based on the current science; I would say fermented foods can play an important role in any diet.
A balanced gut flora has positive links to immunity against a wide range of health conditions.
Lastly, eating small amounts of cultured vegetables each day can introduce millions of beneficial bacteria into our gut.