Steamed Foods, the protagonist in Microbiome Care and Diet



Cooking every day can be annoying for some people even if you want to practice Microbiome Care. Also, even if it's good for our health, eating salads every day can make us tired of it.

But steamed food may be the right answer for those of you.


Some people may think that steaming food is time-consuming, but once you get used to it, it is surprisingly easy.

Moreover, from the standpoint of taking care of the microbiome, steamed food has advantages that make it worthwhile to continue, even if it is a bit tedious.

Today, we KINS unravel the secrets of steamed foods.


Why steamed foods are perfect for Microbiome Care


Do you know the three golden rules we should remember when caring for the microbiome?

Steamed food is the perfect cooking method that meets these three points of microbiome care.

Let's start by reviewing the golden rules of Microbiome Care.


It refers to taking in good bacteria themselves to improve the intestinal environment.

Fermented foods such as Kimchi, yogurt, Nukazuke (Japanese pickles), miso(soy paste), and soy sauce are rich in lactic acid bacterium and other kinds of the microbiome.



For good bacteria to increase more in the intestines, we need to feed them.

Therefore, nutrients such as soluble dietary fiber and polyphenols are necessary. 

In particular, we recommend taking plenty of soluble fiber, which is found in vegetables, beans, grains, seaweed, and mushrooms.

Remember that to grow good bacteria, we need to take not only the microbiome but also the food for them.


Don't be in the microbiome's way.

In addition to taking in the microbiome and soluble fiber to feed them, there's another rule that must not be forgotten. 

That is to avoid the foods that tend to feed the bad bacteria.

Do you usually eat much white sugar, oily food, and red meat?

If your diet is biased toward sweets, excessive fat, and red meat, you might increase the bad bacteria.

When the bad bacteria predominate in the intestines, the good bacteria will be interrupted from exerting their full potential.

Steamed food can meet the three golden rules of Microbiome Care.

Unlike deep-fried or stir-fried dishes, you don't use oil when cooking steamed foods. By reducing fat, you can fulfill the important points of Microbiome Care and lose weight.

In addition to them, heating softens the vegetables and allows you to consume more vegetables than to eat them as a salad without cooling the body.

When combined with fermented seasonings such as miso(soy paste) and soy sauce, you can make a dish that fulfills the three golden rules of Microbiome Care.



Steaming increases the nutritional value


You may have already understood that steamed food is perfect for Microbiome Care and diet.

But steamed food has even more excellent properties than we have mentioned.

That is, steaming increases the nutritional value of food. 

One paper comparing the nutritional value of raw broccoli cooked in two different ways (steamed/boiled) found that boiled broccoli had about 20% less vitamin C than raw. 

On the other hand, there was virtually no change in the amount of vitamin C in broccoli when it was steamed according to this study.


Moreover, the number of polyphenols, which feed the microbiome like soluble fiber, was found to be increased by a factor of 1.6. 


Isn't it amazing that you can increase the number of polyphenols just by steaming?


Also, Flavonoids and phenolic acids, which are excellent antioxidants, were found to increase.


Polyphenols are functional ingredients that reduce active oxygen and are ideal to take daily for health care.

In addition, from the viewpoint of Microbiome Care, it is an important food for the microbiome that increases Bifidobacterium.


Why does steaming increase polyphenols?

You may know that most cooking methods reduce nutrients. 

Among that, it's an interesting fact that steaming can increase polyphenol.


One study suggests that the steaming process destroys the linkages between polyphenols and proteins and causes polyphenols to be extracted.

Although there is no definite theory yet, steamed foods may hold more secrets than we can imagine.


Yet another study found that steaming changes not only the number of polyphenols but also dietary fiber.


One study looked at the change in fiber content in 29 different vegetables after steaming.  As a result, they found an increase in fiber in 20 vegetables.

The amount of increase was different for each vegetable, but broccoli, Brussels sprouts, carrots, onions, celery, radish, and zucchini showed an increase for example.


Moreover, we want to mention the fact that it was the soluble dietary fiber increased by steaming.

There are two types of dietary fiber; soluble and insoluble, and soluble dietary fiber is particularly important for Microbiome Care.

Soluble dietary fiber, like polyphenols, is food for good bacteria, and we at KINS recommend an active intake of soluble fiber. They are indeed partners for our Microbiome Care!

So, we can say steamed foods are the perfect cooking method to take care of our microbiome and our health.



The Vegetables Ideal for Steamed Foods


We have mentioned that steaming increases soluble dietary fiber, an important component of Microbiome Care.

Among them, of particular note are broccoli and Brussels sprouts.

In these vegetables, steaming more than doubled the amount of soluble dietary fiber.


In addition, celery, fennel, and radish, which may be used relatively infrequently in cooking, showed a three-fold increase. 

Fennel is a fragrant herb that is perfect for making "herb steam" by placing it in a steamer with fish and vegetables.


Other increases in soluble fiber were also found in carrots, pumpkins, artichokes, and cauliflower.

We can increase the Microbiome-Care power of many very familiar vegetables by steaming them.



Traditional steaming methods make the difference.


These days, many people use microwave ovens to steam food. However, using a microwave oven is different from using a steamer.

Heating in a microwave oven heats food to a very high temperature in a short period.

Of course, this allows the food to cook thoroughly in a short time, and is perfect for busy people.


However, that ultra-high temperature conversely damages vitamins, polyphenols, and other nutrition.

Therefore, even if that steamed food looks the same, using a microwave oven is less effective for Microbiome Care.

On the other hand, if you use a steamer or bamboo steamer, there is less decrease in many nutrients such as chlorophyll, vitamin C, protein, and soluble sugars.

Of course, microwave ovens help us when we're busy, but it would be nicer to incorporate more old-fashioned tools such as steamers or bamboo steamers into our daily lives.


Other research has also shown that steamed food is the most nutritious compared to other cooking methods such as boiling, frying, and deep-frying.

This is because, unlike other cooking methods, ingredients are not exposed to oil or water during the cooking process.


Importance of raw ingredients

Polyphenols are destroyed by heating at high temperatures, such as in a microwave oven. This problem can be solved by steaming, but in fact, extremely low temperatures also affect the nutrients in vegetables.

One study of frozen Brasenia schreberi(aquatic plant) showed a decrease in polyphenols.

In addition to polyphenols, studies have also shown that freezing vegetables for long periods have reduced vitamin C content.


Year-round frozen pumpkins, garland chrysanthemums, sweet potatoes, and other vegetables, vitamin C, carotene, and other nutrients have been decreased. Although freezing does not cause a rapid decrease, it does not seem desirable to keep vegetables frozen for long periods.


Freezing ingredients is certainly convenient. However, we should say fresh vegetables are the best way to get the full nutritional benefits.


Sulforaphane, your ally in Microbiome Care 

Have you ever heard of sulforaphane?

It is a nutrient found in steamed broccoli sprouts and other food and is a phytochemical that helps increase the body's detoxification and antioxidant capabilities.

Sulforaphane also has a strong antioxidant effect that fights bad bacteria in the intestines.

In other words, it is a reliable ally in Microbiome Care!


The precursor of sulforaphane (the state before it is produced) is glucoraphanin.

Therefore, taking glucoraphanin is also effective for Microbiome Care.

One paper investigated what happens to the content of such glucoraphanin when they are heated and cooked. And again, we found the benefits of steamed foods.


In a study, they examined how much glucoraphanin remained in raw broccoli cooked in various ways, and they found the following results


Steaming: 95

Microwave: 37

Boiling: 60

Stir-fry: 44%

Fried: 47%


As shown above, while most cooking methods reduced glucoraphanin by about half to less than half, as much as 95% remained, undestroyed, in the case of steaming.

In particular, compared to microwaving, the same broccoli is calculated to contain 2.5 times more glucoraphanin.

Polyphenols, soluble fiber, and glucoraphanin.....

Steaming seems to be an ideal cooking method that provides the necessary nutrients for Microbiome Care.



Steamed foods can help you Microbiome Care and lose weight


We have explained how steamed foods are amazing not only to protect the nutritional value of the food but also to enhance it. 

If you are on a diet, you may prefer to eat a low-calorie, nutrient-dense, vegetable-based diet.

But eating a large amount of salad for every meal can be tiresome and make your body cold.

Steamed dishes are a great way to consume plenty of vegetables for those of you. We are sure that you already know that it is a healthy cooking method that does not require oil.


We at KINS recommend using seasonings, such as olive oil, instead of white sugar or chemical seasonings for Microbiome Care.


If you have been eating fatty foods, if you don't like salads that cool you down, if you want to feel full even with low calories, or if you want to take care of your microbiome and lose weight at the same time, you should try warm steamed food to keep your body in balance.





Characterization of fructans and dietary fibre profiles in raw and steamed vegetables

Effect of Year-Round Storage on Vitamin Content in Frozen or Freeze-Dried Vegetables and Fruits

Changes in polyphenol content of Brasenia schreberi during heating and freezing

Mariantonella Palermo, J Sci Food Agric;2014 The effect of cooking on the phytochemical content of vegetables

Jennifer L Kaczmarek J Nutr Biochem,2019 Jan,Broccoli consumption affects the human gastrointestinal microbiota

Laura Lavefve,Food Funct,2020 Jan 29,Berry polyphenols metabolism and impact on human gut microbiota and health