Fermented Foods & Gut Health: What Does the Science Say?
Fermented foods are becoming increasingly popular for improving gut health. We often hear about their beneficial effects, but what exactly falls under this food category? What is fermentation? Do all fermented foods contain live microorganisms? And why are they important?
Let's look at the science behind fermented foods and why not all are created equal.
What is fermentation?
In simple words, fermentation or fermentation is the process that occurs when certain types of microorganisms change the composition of our food and drinks.
Humans have been fermenting foods for years to enhance flavor or shelf life. Today, we know that these live microorganisms are beneficial for gut health , as they can produce vitamins and also potentially have an anti-inflammatory effect.
What are the different types of fermentation?
There are two typical methods. Foods can be fermented naturally, known as “wild fermentation” or “spontaneous fermentation,” where the microorganisms are naturally present in the raw food or processing environment. This is the case with sauerkraut, kimchi, and certain fermented soy products.
Foods can also be fermented by adding starter cultures, often referred to as “culture-dependent fermentations,” for example, yogurt, cheese, wine, beer kefir, kombucha, and natto.
What is the definition of fermented food?
According to ISAPP (The International Scientific Association for Probiotics and Prebiotics), an expert panel was convened to clarify the term 'fermented'; fermented foods and beverages are " foods produced through desired microbial growth and enzymatic transformations of food components ".
This definition includes foods that are made by fermentation but may not necessarily have the live microbes when we eat them. This means that even if the microbes are inactivated or removed during some of the processes, these products still fall into the category of fermented foods.
A clear example of this is leavened breads, where the baking process inactivates the microorganisms, or some beers and wines, where the microbes are removed from the final product.
Not all fermented foods are the same
There are probably countless different fermented foods consumed worldwide. Although the formal definition of fermented foods is very broad, it is important to take into account some practical aspects in order to choose those that benefit our gut health the most.
But one question is whether all of these items are equally beneficial: Is it the same to eat yogurt, kimchi, sauerkraut, or drink kombucha?
How should I choose between fermented foods?
Here are three basic aspects you should take into account when choosing what to buy:
1. Do fermented foods contain live microorganisms?The most important thing is whether the fermented foods contain live microorganisms when they are to be consumed. The key is to read the ingredients list and look for statements such as “contains live and active cultures.” Some products will also list the microbial strains they contain. The claim “the food is made by fermentation” does not guarantee the presence of live organisms.
2. Watch out for added sugar
Unfortunately, many products that we normally consider “healthy” contain higher amounts of added sugar that exceed recommended limits. This can be the case with flavored yogurts or versions of kombucha that we find on supermarket shelves.
Here again, it is a good idea to read the ingredients list and choose products with natural, low sugar or sugar-free content.
Don't be fooled: sugar can be named in different ways, such as corn sugar, dextrose, fructose, glucose, high fructose corn syrup, invert sugar, isoglucose, maltose, molasses, or sucrose, to name a few.
3. Try fermenting at home
Despite the rumors, fermentation is not that complicated. It requires a little preparation, and then the microbes do all the hard work.
If you want to experiment, you can start with one of the simplest fermented foods at home: sauerkraut. It's easy to make, requires very little special equipment, and tastes delicious.
