A Potential Nutritional Link in Long-COVID


I recently read an article about how researchers have developed a computational model to predict the likelihood of long-COVID, analyzing over 6,500 blood proteins. The study, published in Science, compared blood samples from COVID-19 patients and healthy individuals, identifying significant protein differences. The study suggests that specific proteins, especially those related to immune response, blood clotting, and inflammation, are critical biomarkers for diagnosing and managing long-COVID, which is characterized by more than 200 symptoms, including brain fog, fatigue, and chest pain, that can persist long after a SARS-CoV-2 infection.

The finding is an interesting one. However, many of those symptoms share a common thread. Similarly, I think that sometimes, especially in these situations, we should appeal to Occam’s Razor. It seems that this finding merely adds evidence to something I have been pondering for quite some time. It seems to me that a recurring theme has emerged concerning long-COVID. Have you noticed that various nutritional deficiencies might affect the persistence and severity of long-COVID symptoms?

The Role of Nutritional Deficiencies in Long COVID

If you research long-COVID, you will likely find a variety of specific deficiencies common in COVID and long-COVID patients, such as vitamins K, C, D, and B12, calcium, magnesium, zinc, omega-3, iron, and copper. The predictive models are telling, and they allude to an interesting theme. Nonetheless, these deficiencies are significant, considering their roles in immune function, inflammation regulation, and overall health. However, the correlation between these deficiencies and the increasing popularity of certain dietary fads raises questions about the role of modern dietary habits in long-COVID susceptibility. This is to suggest that perhaps the fads are wrong – as they usually are. Only now, we should probably view them as quite dangerous.

Understanding the Protein-Amino Acid Relationship

In my opinion, the protein discovery only adds fuel to this fire. The study in question found several differences in the blood of people with long-COVID compared with those without it, including an imbalance in proteins involved in blood clotting and inflammation. Specifically, they found that people with long-COVID showed lower levels of antithrombin III, a protein that prevents blood clots, and higher levels of thrombospondin-1 and von Willebrand factor, proteins linked to clot formation, compared to healthy individuals and those fully recovered from COVID-19. Additionally, they found that CD41 protein expression on white blood cells was lowest in healthy individuals and highest in those with long-COVID for 12 months. A strong theme seems to be screaming at us.

Surely, I can’t be the only one seeing this. At least, I sure hope that I’m not. Considering the common deficiencies we see, along with this finding specifically, I think we need to look at this a little differently because the theme seems relatively simple. Consider the idea that cysteine, methionine, and glutathione are linked to the changes observed in long-COVID, either directly or indirectly. This fact is quite telling, but it makes sense. After all, they have very specific roles in protein synthesis, immune function, inflammation, blood clotting, and oxidative stress. Understanding these connections is vital as they might provide insights into the pathophysiology of long-COVID and potential therapeutic targets. I’ll explain.

Methionine, an essential amino acid, is crucial for producing cysteine, a semi-essential amino acid with a critical role in forming disulfide bonds in proteins. However, cysteine is also necessary for synthesizing glutathione, a potent antioxidant that is vital in reducing oxidative stress and regulating inflammation and immune responses. Both cysteine and methionine are sulfur-containing amino acids. Methionine is essential in the diet and can be converted into cysteine in the body. However, both amino acids are important for the immune system’s function. This is to say that changes in their levels can affect the immune response, an essential aspect of long-COVID.

Let me be clear. Cysteine is critical for synthesizing various proteins, including antithrombin III, thrombospondin-1, and von Willebrand factor. Disruptions in cysteine availability can potentially affect the synthesis and function of these proteins. Methionine metabolism is involved in the inflammatory response, and abnormal methionine metabolism might contribute to inflammatory conditions. Since long-COVID is associated with a state of chronic inflammation and altered clotting (as evidenced by changes in proteins like thrombospondin-1 and von Willebrand factor), the role of methionine and cysteine in these processes might be very significant. This also provides some interesting insight into glutathione.

We know that glutathione depletion is a dominant mechanism of the immunothrombosis cascade. We also know that COVID-19 patients have increased oxidative stress, oxidant damage, and glutathione deficiency. However, glutathione is composed of glutamate, cysteine, and glycine. These come from very specific sources. Moreover, a deficiency can present itself with many of the symptoms being discussed.

Glutathione plays a crucial role in reducing oxidative stress, which is an imbalance between free radicals and antioxidants in the body. Long-COVID is often associated with increased oxidative stress, so the role of glutathione becomes crucial in mitigating this. Of course, it is also involved in detoxification processes and in regulating the immune response. Well, long-COVID is characterized by prolonged immune dysregulation, where glutathione likely plays a vital part in either mitigating or exacerbating these effects, depending on its levels and activity.

This theme is present in the CD41 finding as well. The expression of proteins like CD41 on white blood cells can be influenced by oxidative stress and the body’s antioxidant status. As glutathione is a key antioxidant, its levels and efficacy could potentially influence the expression of such proteins and the overall behavior of immune cells in long-COVID.

This is to say that an imbalance in these amino acids can disrupt the synthesis of proteins involved in critical bodily functions, such as the coagulation cascade. Incidentally, this disruption can lead to abnormal blood clot formation and contribute to chronic inflammation. In the context of long-COVID, such imbalances could potentially exacerbate or misregulate inflammatory responses, leading to a prolonged illness.

The Broader Picture: Diet and Nutrient Absorption

When considering this theme, it is crucial to consider the therapeutic implications of nutrients like magnesium, vitamin D, and B12 in treating and managing COVID-19. These nutrients align with the emerging theme of dietary influence on the disease’s severity. However, other studies support this idea. For instance, studies have shown a significant correlation between vitamin D deficiency and COVID-19 severity. Patients lacking sufficient vitamin D levels were 14 times more likely to experience severe or critical COVID-19 symptoms than those with adequate vitamin D levels.

Similarly, emerging research indicates that combined magnesium and vitamin D supplements may protect against COVID-19 infection. Interestingly, magnesium, known for its anti-inflammatory properties, may enhance the efficacy of vitamin D, thereby contributing to a more robust immune defense against the virus. Additionally, vitamin B12, which typically comes from a very specific source, is involved in red blood cell formation and neurological function and might also support the body’s ability to combat COVID-19 by aiding in maintaining optimal physiological functions during the infection.

Granted, these are just a few examples, and there are plenty of others that I could share, but again, there is an underlying problem and a very pronounced theme here. What do all of these findings have in common? It seems to me that the commonality is that the best sources of these nutrients are currently being demonized and avoided or not being absorbed due to rampant gut health issues related to inflammation, compromised intestinal lining, or microbiome dysfunction. Of course, avoiding these foods only exacerbates deficiencies in these critical nutrients. Getting sick is only going to make it worse. However, the problem might actually be much bigger.

The deficiencies in these sulfur-based amino acids, essential for many bodily functions, are exacerbated by modern agricultural practices, which have led to depleted sulfur content in soil, plants, and animals. This, in turn, affects human nutrition. At the same time, people are told that supplementing is worthless (which isn’t true). So, the question becomes, where are these individuals supposed to get the nutrients they need to overcome severe illness if they avoid supplementation, avoid the foods they need, or if the food they consume is nutrient deficient in the first place?

There is a reason that specific fad diets result in nutrient deficiencies. Similarly, it seems that a diet lacking copious amounts of animal products and fruits or a diet that is high in anti-nutrients, refined carbohydrates, and sugars can significantly hinder protein creation and deplete vital nutrients in the body. Hence, it seems evident that any illness would likely be both severe and prolonged. Accordingly, it seems the first step in giving the body a chance is to improve nutritional literacy. Therein lies another problem.

The Challenge of Nutritional Education in Healthcare

I have written about this before, but one of the significant barriers to addressing this issue is the lack of appreciation for nutrition and nutritional status. Of course, another barrier might be the fundamental misunderstanding of what “omnivorous” or “anti-nutrient” might mean for humans. This likely stems from the lack of applied nutrition education in medical training or in general.

For my point here, it is important to note that most physicians are not thoroughly taught about the nuances of nutrition and its impact on health, particularly conditions like long-COVID. Similarly, much of the research available began their studies with flawed assumptions about what “healthy” means. This gap in knowledge presents a specific challenge for healthcare professionals attempting to address nutrition-related health conditions in their patients. Of course, this is a scary proposition when you consider that patients are encouraged to talk to their physician about their dietary habits, especially concerning disease.

Closing Thoughts

Granted, I acknowledge that diet alone may not be the sole factor in long-COVID cases. However, Occam’s Razor suggests that it is likely a massive one that shouldn’t be ignored, and the evidence seems to be mounting regarding a potential link between nutritional deficiencies and prevention, as well as the severity of long-COVID symptoms. After all, isn’t it interesting that those sufficient in these nutrients don’t seem to have these issues? A holistic approach, incorporating a better understanding of nutrition (that abandons popular misconceptions) and its impact on health, seems crucial in managing and potentially mitigating long-COVID cases. This perspective also appears to shed light on the importance of dietary choices and underscores the need for greater nutritional literacy among healthcare providers.

If you want to learn more about the diet element of this theme, I encourage you to read Nature’s Intent.

Dr. Robertson is a health researcher and educator, not a physician. The information provided here is not medical advice, a professional diagnosis, opinion, treatment, or service to you or any other individual. The information provided is for educational and anecdotal purposes only and is not a substitute for medical or professional care. You should not use the information in place of a visit, call consultation, or the advice of your physician or other healthcare providers. Dr. Robertson is not liable or responsible for any advice, course of treatment, diagnosis, or additional information, services, or product you obtain or utilize. IF YOU BELIEVE YOU HAVE A MEDICAL EMERGENCY, YOU SHOULD IMMEDIATELY CALL 911 OR YOUR PHYSICIAN.