When it comes to the flu and other viral infections, our body's ability to fight them can depend on how much cholesterol we get into our diet! In fact, a diet high in cholesterol increases inflammation in the lungs and worsens the course of the disease. This emerged thanks to a very recent scientific research published a few weeks ago in The Journal of Immunology by an American team (Louie et al, J Immunol, May 2022).
Cholesterol, benefits and risks
Cholesterol is considered the enemy of our heart but, when not in excess, it is essential for our body. In fact, cholesterol is part of the cell membranes, participates in the synthesis of hormones and vitamin D and ensures the proper functioning of the immune system. Most of the circulating cholesterol is produced by our body which requires only a small part of cholesterol from food. This is why in recent years, in light of this statement, the impact of dietary cholesterol on the health of the cardiovascular system has been significantly reduced. However, if this is true for the heart, it seems that the same cannot be said for the immune system and our ability to cope with external threats, especially if they are of a viral type. Previous studies had been able to suggest a link between cholesterol and defenses. In particular, high circulating cholesterol values were associated with a greater risk of sepsis in the case of a viral infection caused by the flu. Not only that, the use of drugs to lower cholesterol has improved survival in the event of flu, new coronavirus and sepsis. However, the link until now was unclear and nothing was known about the role of dietary cholesterol.
Foods rich in cholesterol and inflammation
To understand the role of dietary cholesterol on the body's ability to cope with external threats and viral infections, American scientists performed a laboratory study on a population of mice. One part of the mice was given a standard diet, the other part a standard diet with the addition of cholesterol. After 5 weeks the mice came into contact with the influenza A virus. What emerged was that the mice that had eaten the diet with the addition of cholesterol had more serious consequences regarding the disease and greater loss of weight. The explanation for what was observed is that the lungs of mice that had taken in a higher amount of cholesterol had a higher level of inflammation even before the viral infection.
Therefore, the immune system was already weak and with an excessive level of pro-inflammatory substances. And, more importantly, the harmful effects of the high-cholesterol diet were also observed up to 5 weeks after the mice resumed eating the standard diet without cholesterol additions.
Here is further proof of the importance of a healthy and varied diet that is not too high in cholesterol. Foods rich in cholesterol are eggs, especially the yolk, but also cheeses, butter, shrimp, pork and beef. With this we are not saying that it is necessary to eliminate these foods from our diet, but only that it is important to be aware of what we are eating and not to overdo it with this type of food during the same day.