A presentation by the WHO shows that approximately 9% of people who have been infected with the coronavirus develop new allergies, while around 12% report an increase in reactions to existing allergies. These reactions can be to medications or other substances. Link to the presentation WHO.
Food allergies and intolerances in long COVID
Many individuals with long COVID report significant changes to their bodies after contracting the virus. Alongside the familiar symptoms of fatigue, difficulty concentrating and breathing problems, some patients have noticed a common occurrence: foods that were previously tolerated suddenly cause discomfort. Others find that existing allergies or intolerances have worsened, or that new ones have developed.
But is there any medical information on this? How can this issue be classified?
Observations from the everyday lives of those affected
Similar reports come up again in self-help groups, forums and conversations with those affected:
- New intolerances to certain foods
- stronger reactions to already known allergens
- Complaints after eating, such as
- gastrointestinal problems
- skin reactions (itching and redness)
- headaches, dizziness
- worsening fatigue
Reactions to foods rich in histamine, such as mature cheese, tomatoes, alcohol, and ready-made products, are particularly common.
Histamine is a messenger substance produced by the body which, among other things, increases the permeability of blood vessels and irritates nerves. This can cause symptoms such as swelling, itching, skin redness or headaches. It is important to note that not every reaction to foods rich in histamine is automatically an allergy. Often, these are intolerances or hypersensitivity reactions.
Further information on histamine, its symptoms and foods that contain it can be found on the website of the Swiss Histamine Intolerance Interest Group: SIGHI
What research has to say
Research into long-term effects of the virus continues apace, particularly about the immune system. It is now clear that the virus can have a lasting impact on immune function.
One mechanism under discussion concerns mast cells. These cells form part of the immune system and act as an early warning system. They contain various messenger substances, including histamine, which is released when they are activated.
Experts suspect that infection with the coronavirus can lead to immune system dysregulation. This could cause mast cells to become excessively or inappropriately activated, resulting in increased histamine release. This could explain why some people react more strongly to certain foods or develop new allergy-like symptoms following a Coronavirus infection.
In addition, changes to the intestine and intestinal barrier are being discussed, which could further influence food tolerance. However, large, definitive studies on newly emerging food allergies in long COVID are currently lacking. At present, much of the evidence comes from smaller studies and clinical observations.
Why does nutrition play a role in long-term effect of the virus?
Nutrition is more than just food. It affects inflammation, energy levels and overall well-being. This is especially true in the case of long-term effects of the virus, where fatigue is one of the most common and debilitating symptoms.
Looking beyond the horizon, we can see an interesting parallel with other chronic diseases, such as multiple sclerosis (MS). MS is also a chronic disease for which fatigue is a central symptom. The Swiss MS Registry, for instance, has investigated which dietary patterns can positively impact fatigue. Link to article
Of course, MS and long COVID are not the same thing. Nevertheless, some basic considerations can be applied to both:
- A low-inflammatory diet
- Eating regular, balanced meals
- Avoiding foods that cause personal intolerances
- Adequate fluid intake
These aspects may also benefit people with long-term effects of the virus, especially when dealing with fatigue and general exhaustion.
What can those affected do?
If you suspect that certain foods are exacerbating your symptoms, the following steps may help:
- Keep a food and symptom diary
- Make changes gradually rather than radically
- Seek medical advice in case of severe or unclear reactions
Important: Since diet can affect well-being, self-diagnosis or severely restrictive diets should not be undertaken without professional guidance.
