Immune Support through Food
This year has increased our awareness about health and wellness, especially as the dominant conversation evolves around COVID-19. One thing that we each can do during this pandemic is direct our attention towards ways that we can build our immune system to prevent infections, or at very least, support our body's response and recovery rate. The primary focus currently is wearing a mask, practicing physical distancing, and proper personal hygiene. While all of these modalities may, or may not, be effective at flattening the curve, we have a personal responsibility of self-care to help promote a healthier immune response. Nutrition, supplements, herbs, and lifestyle can all be critical players in boosting your immune system.
The journal of Nutrients published an article on the role of diet and nutrition and strengthening the immune system in May of this year (Iddir et al., 2020). To have an optimally functioning immune response, we have to provide the body with the adequate nutrients it needs. For example, the body requires sufficient protein stores to produce antibodies for fighting infections (1). Amino acids, the building blocks of protein, can influence the immune response as well. For example, arginine found in lean meats, nuts, and seeds can aid in the production of nitric oxide by macrophages and many other immune cells that help prevent pathogen replication (2, 3). Glutamine, another amino acid found in meat, seafood, cabbage, and eggs, is a source of energy for the cells involved in the immune response (2).
Foods that are higher in glycemic index (quickly increases blood sugar) produce oxidative damage and inflammation, putting the body in a highly inflamed state (1). Trans fats and the overconsumption of specific saturated fats may also lead to inflammatory conditions. Complications of COVID-19 are thought to be induced by the hyper-inflammatory response from the body triggered by the viral replication (1). Having chronic inflammation in the body dysregulates the immune system and increases the risk of infection as well as increase the risk of complications (1). Aside from COVID-19, inflammation is a contributing factor to many other co-morbidities such as cardiovascular disease, diabetes, and strokes.
Many biomarkers can determine a person's level of inflammation, but one that has recently gained attention for COVID-19 prognosis is the cytokine interleukin 6 (IL-6). A meta-analysis of COVID-19 complications and IL-6 levels demonstrated that people that experienced more severe illness and increased mortality risk had IL-6 levels three times higher than those that did not (4). The drastic spike in IL-6 is the "cytokine storm" that many people were posting about at the beginning of COVID-19. Reducing this cytokine is currently being investigated as a potential drug therapy treatment (4). Diets high in trans fats, certain saturated fats, and sugar increase the production and secretion of IL-6 while polyunsaturated fatty acids, like omega-3 rich fish, and fiber may lower IL-6 levels (5). Mind you, IL-6 is a normal inflammatory response in acute inflammation states, but chronically elevated levels become problematic.
The name of the game for promoting a functioning immune system is reducing inflammation and inflammatory triggers, as well as reducing oxidative stress. Including fruits and vegetables that are rich in colors can provide phytonutrients, plant chemicals with potent antioxidant and anti-inflammatory properties. Quercetin, for example, is a nutrient found in apples and onions that studies indicate can decrease viral infectivity and intracellular viral replication (1). Carotenoids, like seen in carrots, reduce inflammation and oxidation, as well as provides immune-boosting support when converted to vitamin A (1). Also, polyphenols and other plant nutrients can act as prebiotics for our microbiome, meaning food for your gut bugs. In the next blog post, I will touch on what the science says about the role the microbiome plays in our immune system and COVID-19.
Acute inflammation is a normal response of the immune system to harmful stimuli. But when the body is in a state of chronic inflammation, the immune response becomes dysregulated by multiple pathways. One of the paths, as it relates to this article, is by causing a zinc deficiency. Zinc is an essential micronutrient required for the development and function of immune cells (6). Zinc has antiviral effects that many studies report being due to the ability to suppress viral replication (6). Increased inflammation and IL-6 levels can contribute to a deficiency of zinc (7). Yet being deficient in zinc can cause the immune system to become dysfunctional, igniting an inflammatory immune response (8). What came first, the chicken or the egg? Nevertheless, zinc is essential, and its role in the immune response doesn't go unnoticed. Did you know that chloroquine acts as a zinc ionophore, pushing zinc into the cells (9)? Foods rich in zinc include pumpkin seeds, oysters, red meat and poultry, beans, and seafood.
At the beginning of the pandemic, I wrote an article on my speculation of vitamin D deficiency being a potential risk factor for severe infection (you can find that article here). Vitamin D plays a protective role in respiratory tract infections (6). There are vitamin D receptors located in the majority of immune cells, which suggests a role in immune function. How vitamin D reduces viral risk is unknown, as vitamin D contributes to many parts of the immune system. Still, the fact remains adequate vitamin D levels reduce the risk for viral infections (6). Many studies are underway on vitamin D status and COVID-19 risks. There is a correlation with higher infection rates in countries more north of the equator with typical low vitamin D status (10). We are getting ready to head into winter, folks. Now is the time to have your primary care physician to screen your vitamin D levels. We get most of our vitamin D through sun exposure, but some food contains trace amounts like fortified foods, fish, and mushrooms.
The examples provided above are just a glimpse into the role food and nutrients can play on the immune system. Stress, physical activity, and sleep patterns are also influential components for the immune response, and there is room for more discussion on each of these topics. The biggest take away I want my readers to understand is that our body requires specific nutrients to function correctly. When we are discussing ways to stay healthy and happy, we can't ignore the basic biological necessities – good food, real food. While this invisible monster has wreaked havoc on our lives, there are things that we can do for ourselves. It is time to take back our power and opt-in for natural self-care.
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Resources:
|1| Iddir, M., Brito, A., Dingeo, G., Fernandez Del Campo, S., Samouda, H., La Frano, M.R., & Bohn, T. (2020). Strengthening the immune system and reducing inflammation and oxidative stress through diet and nutrition: Considerations during the COVID-19 crisis. Nutrients, 12(1562). DOI:10.3390/nul2061562
|2| Childs, C. E., Calder, P. C., & Miles, E. A. (2019). Diet and Immune Function. Nutrients, 11(8), 1933. https://doi.org/10.3390/nu11081933
|3|Tripathi P. (2007). Nitric oxide and immune response. Indian journal of biochemistry & biophysics, 44(5), 310–319.
|4| Grifoni, E., Valoriani, A., Cei, F., Lamanna, R., Gelli, A., Ciambotti, B., Vannucchi, V., Moroni, F., Pelagatti, L., Tarquini, R., Landini, G., Vanni, S., & Masotti, L. (2020). Interleukin-6 as prognosticator in patients with COVID-19. The Journal of infection, 81(3), 452–482. https://doi.org/10.1016/j.jinf.2020.06.008
|5| Maggio, M., Guralnik, J. M., Longo, D. L., & Ferrucci, L. (2006). Interleukin-6 in aging and chronic disease: a magnificent pathway. The journals of gerontology. Series A, Biological sciences and medical sciences, 61(6), 575–584. https://doi.org/10.1093/gerona/61.6.575
|6| Gasmi, A., Noor, S., Tippairote, T., Dadar, M., Menzel, A., & Bjørklund, G. (2020). Individual risk management strategy and potential therapeutic options for the COVID-19 pandemic. Clinical immunology (Orlando, Fla.), 215, 108409. https://doi.org/10.1016/j.clim.2020.108409
|7| Liuzzi, J. P., Lichten, L. A., Rivera, S., Blanchard, R. K., Aydemir, T. B., Knutson, M. D., Ganz, T., & Cousins, R. J. (2005). Interleukin-6 regulates the zinc transporter Zip14 in liver and contributes to the hypozincemia of the acute-phase response. Proceedings of the National Academy of Sciences of the United States of America, 102(19), 6843. https://doi.org/10.1073/pnas.0502257102
|8| Wong, C. P., Rinaldi, N. A., & Ho, E. (2015). Zinc deficiency enhanced inflammatory response by increasing immune cell activation and inducing IL6 promoter demethylation. Molecular nutrition & food research, 59(5), 991–999. https://doi.org/10.1002/mnfr.201400761
|9| Xue, J., Moyer, A., Peng, B., Wu, J., Hannafon, B. N., & Ding, W. Q. (2014). Chloroquine is a zinc ionophore. PloS one, 9(10), e109180. https://doi.org/10.1371/journal.pone.0109180
|10| Biesalski H. K. (2020). Vitamin D deficiency and co-morbidities in COVID-19 patients – A fatal relationship?. Nfs Journal, 20, 10–21. https://doi.org/10.1016/j.nfs.2020.06.001