Building up intestinal flora - with the golden rule of nutrition (including daily plan)

The most important rule of a gut-healthy diet

One of the most important basic rules for a healthy diet is to eat as colorful as possible - ideally as colorful as a rainbow every day! And this does not refer to colorful gummy bears or artificially colored yogurts. Rainbow nutrition is about something else: natural vegetables and fruits such as orange carrots, green spinach, red tomatoes, blueberries, as well as nuts, seeds, herbs, and legumes. But why is this actually so important and when can we speak of a diverse diet?

Why is plant diversity so important for the gut?

1. Diversity promotes the abundance and strength of beneficial gut bacteria in the microbiome

Our gut is home to millions of microorganisms that live in symbiosis with humans. We feed them with valuable fibers, and in return, they help us defend against pathogens and provide important energy for our intestinal cells. Our gut flora consists of a variety of different strains of bacteria, each digesting something different. If the diet is very one-sided and therefore always provides the same nutrient profiles, not all strains of bacteria are fed. Consequently, the diversity of bacteria in the gut decreases, which is essential for our health.

On the other hand, a diverse plant mix provides various nutrients and fibers, promoting a wide diversity and proliferation of protective bacteria.

The good news is: Our microbiome is influenced daily by our diet. This means that by increasing your intake of vegetables and other foods, you can already positively influence your microbiome within a few days. In a study, participants were given 24 different plant-based foods to eat over several days, significantly more than usual. The result was that within this short period of time, the abundance of beneficial gut bacteria measurably increased. Among them, for example, bacteria from the group of Firmicutes, which convert fiber into short-chain fatty acids such as butyric acid. Although butyric acid may not sound delicious, it is exactly that for our intestinal cells. Butyrate is one of their most important sources of energy and is essential for the health of our intestines, such as for an intact intestinal barrier. A large part of our immune cells also reside in the gut, and they too benefit from an adequate amount of short-chain fatty acids.

2. More secondary plant compounds for gut health

The positive influence of a diverse diet is not only based on the variety of vitamins and trace elements. The more different types of fruits, vegetables, herbs, etc. we eat, the more different vitamins, trace elements, antioxidants, and especially secondary plant substances we absorb. Secondary plant substances are the color, scent, and flavor compounds in plants. 100,000 of them are known so far, with 5,000 to 10,000 of them coming from our foods. For example, allicin gives garlic its smell and the carotenoid lycopene gives tomatoes their red color.

The most important secondary plant compounds include:

• Carotenoids (such as beta-carotene, astaxanthin, zeaxanthin, lycopene in carrots, pumpkin, or tomatoes)

• Chlorophyll (found in green leafy vegetables such as spinach and chard)

• Flavonoids (found in yellow, red, and blue fruits and vegetables)

• Glucosinolate (for example in broccoli, red cabbage, and kohlrabi)

• Phytosterols (found in nuts, legumes, soy)

• Polyphenols (e.g. resveratrol in grapes)

• Saponin (found in legumes, oats, asparagus)

• Sulfide (in onions and leeks)

Together with vitamins and trace elements, they determine the health value of plant-based foods. The immune system located in the gut can particularly benefit from the immunomodulating function of secondary plant compounds, as stated by the German Nutrition Society on their website¹. Researchers suspect that they influence the balance of gut bacteria and improve the barrier function of the intestines, which in turn affects the development of inflammation.

Secondary plant compounds pass undigested into the colon and serve as food for the intestinal bacteria. They have a prebiotic effect. The resulting short-chain fatty acids provide energy to the cells of the intestinal mucosa and lower the pH of the colon, creating an acidic environment that in turn prevents the colonization of pathogenic bacteria in the intestine.

Numerous observational studies confirm a connection between secondary plant compounds and our well-being on various levels. However, these positive results do not apply to isolated substances. Besides high concentration, the composition is crucial. Only when secondary plant compounds are preserved in their natural environment can they have an effect on the organism. Therefore, diverse consumption of fruits, vegetables, legumes, nuts, and seeds as suppliers of secondary plant compounds is recommended and also has a preventive effect on the gut and health!

3. Plant diversity ensures our nutrient supply

You eat two apples and three carrots daily? That's a good start, but scientists recommend that in a week there should be at least 25 different plant-based foods. Researchers know very well why such a variety of vegetables, fruits, and herbs keeps us healthier than always consuming the same types. Whether broccoli, apple, or raspberry: each type contains its own spectrum of nutrients and specific phytochemicals that complement each other. No single food can provide us with all essential nutrients, which is why even eating cabbage vegetables all day is not healthy. Only a colorful diet provides us with all the beneficial substances that the plant world has to offer.

25 per week: How to achieve natural diversity for the gut

Eat the rainbow: Eat as colorful as possible every day!

A good rule of thumb is to aim for 25 different types of fruits and vegetables per week.

This may sound like a lot at first, but with a few tips and our daily plan, it will definitely be easier for you to eat more diversely and thus positively influence your microbiome.

• Eat according to the season: If you follow nature, it automatically leads to eating a more colorful diet.

• Eat a variety of foods within a color group: When you think of "orange," don't just think of carrots, but also sweet potatoes, mangoes, and pumpkins. Instead of always choosing tomatoes, opt for beets, pomegranates, and red bell peppers.

• New shopping habits: Automatically, we tend to always choose the same types of vegetables in the produce section. Next time you go shopping, why not try out new types of vegetables and fruits, including those you have avoided so far!

• A dish as a rainbow: Make a salad or a bowl for a colorful treat - and you have covered the whole color palette with one meal!

• Daily 5-7 servings of fruits and vegetables: Increase your daily intake of fruits and vegetables to three to five servings of vegetables and two servings of fruits, with one serving being roughly equivalent to a handful.

Add some color to your shopping basket and enjoy the full variety of colorful meals!