Tedros A. Ghebreyesus, director general of the World Health Organization (WHO) has launched a message that is going around the world. The message is related to the importance of having good habits and a healthy diet in order to be healthy and with good immunity when facing the coronavirus crisis (COVID-19) . When it comes to good habits, it includes: being physically active, avoiding alcoholic or sugary drinks, not smoking, and taking care of mental health. These are the basic premises to seek good health and a good state of the immune system.
Relationship between gut microbiota and immunity
We know that there are several factors that influence the implantation of a correct intestinal microbiota . Some of these factors are: genetics, the type of delivery, the type of breastfeeding, the use of antibiotics, the infection by different pathogens and, of course, the type of diet we eat.
The food plays a key role in regulating the intestinal microbiota . Therefore, food also influences the regulation of our immune system.
How is the relationship between the immune system and the gut microbiota produced?
In the intestine we have more than 1 kg of microorganisms that play an important role in the functioning of our body. If everything works properly, there is a symbiosis where host and guest benefit from each other . For example, there are some bacteria that participate in the production of enzymes, vitamins such as vitamin K and some of the B complex and act together with intestinal mucus, as a barrier against pathogens. Basically, it is a coexistence that must be very careful.
To achieve a good relationship, the first thing our intestinal and immune cells have to do is be able to recognize whether microorganisms are good or bad . In this way, they can learn to fight against those that pose a threat to our health. How ?: Triggering an inflammatory process in response .
The inflammatory response of the immune system
In our intestinal microbiota there is a “physiological” inflammation mediated by beneficial Immunoglobuins A. This inflammatory response must be increased when the entry of a pathogenic microorganism is detected , in order to fight with it. This occurs, for example, in the case of gastroenteritis that usually improves without the need for medication.
It should be noted that the immune system works in a very complex way. Sometimes an inflammatory immune response can be so exaggerated that we need anti-inflammatory treatments to regulate it. This can happen in hospitalized COVID-19 patients who are already receiving antiviral medications. However, it is important to emphasize that this part of immunity is more related to genetic predisposition than to the intestinal microbiota.
Food and intestinal microbiota
You may be wondering what type of food our intestinal microbiota needs to function properly. Its main food is fiber and some types of carbohydrates present in various foods of plant origin. These act as good prebiotics, so they should be the protagonists in your diet. For this reason, we encourage you to promote the consumption of vegetables, legumes, fruits, whole wheat products, nuts and seeds . These foods are not only related to the prevention of chronic diseases such as obesity, diabetes or cardiovascular diseases but also to the implantation of an adequate intestinal microbiota. This is important, because a healthy microbiota will strengthen our immunity. In other words, these plant foods are good for our own cells as well as for the cells of our microbiota.
In relation to proteins and fats, these must be provided in their proper measure. An excess of these macronutrients enhances the growth of microorganisms that are not so friendly to our intestines. Ultra-processed foods or foods with excess additives are those that will negatively affect the intestinal microbiota.
Could probiotics or prebiotics help prevent COVID-19?
Currently, there is no evidence that probiotics, prebiotics or symbiotics reduce the risk of COVID 19 infection. However, microbial dysbiosis was identified in some people, with a significant decrease in intestinal probiotics. For this reason, it is likely that the use of prebiotics or probiotics may be beneficial, although more research is required to establish dosages and criteria for use.
What nutrients should I pay more attention to to improve my immune system?
We must bear in mind that there are some nutrients that contribute to the proper functioning of the immune system. The main ones are: vitamin A, vitamin B6, B9, B12, vitamin C, vitamin D, vitamin E, copper, iron, selenium and zinc. However, by themselves, they will not eliminate the risk of infection or cure the disease. The European Food Safety Authority (EFSA) concludes that isolated consumption of these nutrients is unlikely to be associated with a lower risk of infection.
As a general guide, we can say that carrots and orange vegetables are rich in vitamin A and blue fish is rich in vitamin D . Vitamin C is present in all foods of plant origin; especially in peppers, citrus fruits, kiwi… Spinach and very green vegetables are rich in Vitamin B6 and Vitamin B9, as are dried soybeans and legumes. Wheat bran is rich in magnesium. Fish and shellfish are rich in vitamin B12, iron, selenium, and zinc. Dairy products are rich in calcium, and when fermented, they provide some probiotics. Including these foods in our daily diet ensure the supply of all the necessary nutrients to have a good immune system .
A healthy and balanced diet as a base
Therefore, the general recommendation is to maintain a balanced and healthy diet . This means that it is made up of 70% food of plant origin and completed with food of animal origin. As a guide, we can use the plate method . In case of eating an omnivorous diet, it would be the correct way to provide all the necessary nutrients described to improve our immunity and our microbiota. Both are feedback.
Although it is known that there are no foods that can prevent infecting us with COVID-19, trying to maintain a strong immune system can help us modulate the response to any infection. Also, maintaining a normal body composition will help us better regulate immunity. This is because excess body fat, as in obesity, increases the inflammatory process and encourages the implantation of an altered microbiota. The same happens with a sedentary lifestyle or the consumption of toxic substances such as alcohol or tobacco.
The importance of food hygiene as prevention of COVID 19
Finally, we must remember that maintaining good hygiene practices during the purchase, handling, cooking and preservation of food will avoid cross contamination and the risk of contracting any infection. Keeping your hands always clean is being key in this whole process.