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High Cholesterol Diet Increases Lung Inflammation, Making Influenza and Other Infections More Severe

Updated: Aug 31

JAMES MESCHINO, DC, MS, ND

Source: Journal of Immunology (May 2022)



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Have you ever wondered why some people who get infected with the influenza virus develop life-threatening complications and other people infected with the same virus have only mild symptoms? Well, there are many explanations for this, including differences in nutritional status, co-morbidity issues (like having diabetes), or having a weakened immune system due to the aging process or the use of certain medications. But some new research published in the Journal of Immunology in May 2022, has shown that eating high cholesterol foods appears to be a major factor in promoting more severe infections, especially in the lungs.


As the researchers point out, previous studies on humans have shown a link between high-fat diets and elevated blood cholesterol with increased susceptibility to infection and lowered immune response. For example, obesity is a well-known risk factor for severe diseases in COVID-19 and influenza. We also know that high serum cholesterol levels can lead to a higher risk of sepsis in influenza infections.


The 2022 study has now shown us “how” high cholesterol diets are likely linked to worse outcomes for people who develop these infections. This study showed that feeding mice a high cholesterol diet significantly increases the severity of influenza A viral infection compared to mice fed a low cholesterol diet.


The high cholesterol foods stimulated the immune cells, especially in the lungs, to overproduce inflammatory cytokines, leading to the notorious cytokine storm that is often the final and life-threatening step that occurs in severe influenza and COVID infections. We know that preventing cytokine storm is an important way to prevent major complications of COVID-19 and influenza infections.


So, this animal model helps to explain what we have observed in human cases of influenza and COVID-19, where higher cholesterol blood levels increase the risk of having more serious, and life-threatening outcomes. In fact, in the mouse model, even before the introduction of the influenza virus the high cholesterol diet alone was already producing inflammatory changes in the lungs. It was in, some respects, preparing the lungs for a more adverse reaction should a virus show up at some point down the road. The researchers stated, “our data collectively show that dietary cholesterol increased morbidity in influenza-infected mice. The response appeared to be a result of an aberrant immune response occurring in the lungs rather than an effect of the virus itself.


These results demonstrate the need to consider how host factors contribute to disease outcome.” The word host means your body and the internal environment of your body. This means that your body’s internal environment largely determines the severity of the symptoms you’ll experience if you contract one of these viruses. Eating high cholesterol foods is one of the factors that create an internal environment that enables certain viruses to produce more severe and serious infections. I have suggested for a long time that eating high cholesterol foods is very undesirable. Of course, having high blood cholesterol is strongly linked to cardiovascular disease – the number one killer in our society. But high cholesterol foods are dangerous for other reasons, and now we see their detrimental effects on the increasing risk of more severe and life-threatening infections. So, for many reasons, I suggest you avoid eating high cholesterol foods, which include foods such as:


  • Egg yolks

  • Organ meats (liver, kidney, brains)

  • Any milk of yogurt above 1% milk fat

  • Butter

  • Cheese

  • Ice cream, cream, sour cream- all high-fat dairy products essentially, including ghee (clarified butter)

  • Red Meat (Beef and pork products)

  • Many pastries, which often contain butter, cream, and/or egg yolks.

  • And be careful with too much shellfish

I have included the references for this information in the text below.



References

  1. Dietary cholesterol worsens inflammation, sickness in mice with influenza. ScienceDaily. https://www.sciencedaily.com/releases/2022/05/220519164853.htm

  2. Allison Y. Louie, Joseph Tingling, Evan Dray, Jamal Hussain, Daniel B. McKim, Kelly S. Swanson and Andrew J. Steelman. Dietary Cholesterol Causes Inflammatory Imbalance and Exacerbates Morbidity in Mice Infected with Influenza A Virus. Journal of Immunology, 2022 https://pubmed.ncbi.nlm.nih.gov/35577367/