How food affects your child’s health and immune system

Hi Carina! Let’s start with an obvious question: gut flora – what are they?

That’s a good question! Gut flora, or gut microbiota, is a term for all microorganisms that live in our digestive tract. Bacteria make up the majority of our gut flora, and healthy flora in a healthy person contain a large number of different bacteria. Bacteria have previously had a bad reputation, which is completely undeserved. Sure, there are bacteria or microorganisms that are bad for us – those that cause food poisoning, tonsillitis and other infections – and we would prefer not to have them. But recent research shows that the vast majority of bacteria are good and important for us. Researchers have actually started viewing our microbiota as a separate organ that is at least as important as our brain and heart. An imbalance in our gut flora can lead to a number of diseases, such as obesity, cancer, cardiovascular diseases, allergic diseases, autoimmune diseases and even depression.

Is it true that our gut flora are also important for our immune system?

Yes, that’s correct! Research has shown that the microorganisms we have in our gut flora can affect our immune system. The fact is that approximately 70% of our immune system is located in our digestive tract. The bacteria produce, among other things, substances that fight inflammation in the body, and this is very important, as inflammation is the cause of many chronic diseases. In fact, our digestive tract communicates with almost every other organ in our body.

So why are children’s gut flora so important?

When children start eating solid food, their bacterial diversity increases drastically, and it is at this stage that we probably have the greatest chance to influence developments. The period up to the age of 3 is the most important period in life when it comes to establishing gut flora. And why is that so important, you may be wondering? Well, the role played by the various microorganisms includes ensuring that our immune system matures in the right way. After the age of 3, our gut flora are already established and will largely accompany us throughout life. But that doesn’t mean it is too late to do something if you have older children or are an adult, because lifestyle and diet continue to be important for our digestive tract (and the rest of our body) throughout our life.

In what way does the type of food we eat impact our gut flora?

There is one thing in particular that has a major impact in determining which microbes end up living in a child’s digestive tract, namely the food that we eat. Just as plants need the right nutrition and good conditions to thrive, our gut bacteria are also dependent on the right nutrition. There is a lot of research indicating that what we eat directly affects our gut flora and determines which bacteria will thrive in our digestive tract, and there is also evidence that a less varied diet, a lot of ready-made food and a low intake of fruit and vegetables are all factors that inhibit the development of our gut flora. Instead, what our gut bacteria need is FIBRE. Dietary fibre is a general term for carbohydrates that are not broken down in the small intestine but are instead transported, undigested, to the large intestine to “feed” our gut microbiota.

So what types of food should parents choose for their children?

The key to maximising our sources of fibre is to have a varied diet. Examples of the types of food that contain fibre include fruit and vegetables as well as legumes such as beans and lentils. These types of food are called PRE-biotics because they stimulate the growth of the beneficial bacteria in our digestive tract. One more thing: There are different types of fibre! Fibre from asparagus can stimulate the growth of one type of bacteria, while the fibre found in a sweet potato can promote a completely different type of bacteria. In other words – the more different types of fibre you consume into your body (and your digestive tract), the better.

So when you start introducing solid food to your child, try to include different types of fibre-rich food. Children of this age are usually very receptive to various vegetables and legumes. Try making homemade porridge with different types of cereal, such as oats, quinoa, millet or buckwheat. Use coarse-grain products that contain much more fibre than fine-grain products. Replace white pasta with whole grain pasta. Buy brown rice instead of white rice. Eat more legumes, such as lentils, chickpeas and beans. Not only are they rich in protein and nutrients, they also contain lots of good fibre.

But what should parents do if they have a child who doesn’t want to eat vegetables or legumes?

I myself had a 2-year-old who sometimes only wanted to eat bread and pasta, so I completely understand the frustration of parents in such a situation! My advice is: try not to give up, and don’t place unnecessary pressure on yourself or your child. The day will suddenly come when your child is once again interested in more varied food, and in the meantime you can perhaps find ways to add more fruit or vegetables to your child’s diet without him or her noticing. If you are making pasta sauce, for example, you can try adding some lentils and vegetables, such as mushrooms, onions and spinach. Blending the sauce can be a good idea if your child refuses to eat individual pieces of vegetable. Smoothies can also work well. Add fresh or frozen berries, mango, banana, kale and various seeds. Frozen vegetables such as squash, cauliflower and avocado have a very neutral taste and are perfect for a smoothie. I usually pour any leftover smoothie into ice cube moulds that I keep in the freezer – they are always popular with the kids! And last but not least: Invite your kids to help you with the cooking, and let them choose a new type of fruit or vegetable when you’re at the supermarket, one that they haven’t tasted before. Talk about different types of food and how important it is that we not only feed ourselves, but also our good and hard-working bacteria that do their best to keep us healthy!

If we reverse the question – are there any types of food that are directly bad for a child’s health and immune system?

I would say that our gut bacteria’s least favourite type of food is probably ultra-processed food. In other words, food that is industrially produced and heavily processed, with ingredients that are not typically used in home cooking. Ultra-processed food contains many substances that are added to aid its taste, texture and appearance: artificial colouring, flavour enhancers, emulsifiers and preservatives. Typical examples include pastries with a long shelf life, sweet breakfast cereals, cheap sausages, chicken nuggets and other finished products, margarine, energy bars, ready-made desserts and puddings. Surveys from the USA, Norway and several other countries show that more than half of the food bought by most people can be categorised as highly processed goods. Because microbiota research is so new, there is still much that we do not know, but research studies suggest that the use of preservatives and additives in ready-made food disrupts our microbial community. It is therefore my recommendation that people should reduce their intake of ultra-processed food.

If parents are concerned that their children are not getting enough variety in their diet, is it a good idea for them to give their children food enriched with probiotics?

That’s a good question! Although the research literature regarding human microbiota has exploded in the last decade, there is still much that we do not know, and there is no convincing research to suggest that probiotics have a beneficial effect on healthy children. The biggest problem, however, is the dubious quality of the studies performed, which often have shortcomings. Different studies have used different bacteria compositions, and few people have been included in the studies. While we wait for clear research results, my advice to parents is to give their children prebiotics, which are available in abundance through food. The research is quite clear in this regard.

Carina’s best tips on how to promote the development of good gut flora in your child:

• Allow your child to taste many different kinds of food, in order to increase microbial diversity. This is particularly important for children under three years of age.
• Try to introduce a variety of breads and cereals at an early age, preferably based on different types of cereal such as wheat, barley, rye and oats. But introduce fibre gradually, as too much fibre can cause children to experience constipation or diarrhoea.
• Start offering your child vegetables at an early age. Does your child refuse to even touch a vegetable? Don’t give up – keep putting vegetables on the table, but don’t nag your child about eating them. Try putting one type of vegetable in each bowl so that your child can make his or her own choice. Perhaps you can vary things by introducing new vegetables that your child has not tried before, and it could help if you cut them in a fun way or let your child help set the table (if he or she is old enough). Anything that increases your child’s interest and engagement is positive. However, you should take care not to give your child excessive amounts of leafy greens before he or she is one year old.
• Don’t forget legumes, such as lentils, peas and chickpeas. They can be varied in terms of different textures, which may make it easier for your child to accept them.

Please note that all information above is based on Swedish recommendations.