It seems that vitamin C, vitamin D, and zinc are among the most talked about nutrients in relation to COVID-19. I already delivered the truths about vitamin C & D in terms of their true power in preventing or treating this virus, but let’s take a look at zinc.
Zinc is a trace mineral that is essential for growth, development, and managing the complexity of the immune system. It is found throughout all systems, organs, and tissues of the body. The World Health Organization (WHO) estimates that up to 31% of the world is deficient in this mineral, but the National Center for Biotechnology Medicine (NCBI) estimates <15% of zinc deficiency exists in the United States.¹
The functions of zinc include:
- RNA synthesis and gene expression
- Cofactor to more than 300 enzymes
- Aid in alcohol metabolism
- Immune function
- Protein synthesis
- Stabilizes cell membranes
Sufficient zinc levels can reduce the risk for premature births, all-cause mortality, and stunted growth in children. In addition, zinc supplementation can decrease the duration and severity of child diarrheal episodes and Acute Lower Respiratory Infections (ALRI).¹ As we now know, COVID can cause both upper and lower respiratory infections, so zinc supplementation could potentially reduce the duration and severity of a viral-induced infection.
In a study conducted in 2019 in Thailand, children suffering from ALRI who were administered 30mg of zinc/day recovered 1 day faster and were released 3 days earlier from the hospital than the placebo group. A similar study carried out with Indian and Bangladesh children resulted in similar conclusions- less severe cases and a shorter stay in the hospital.²
The mechanism by which zinc supplementation improves the symptoms of ALRI is unknown. Theoretically, zinc is essential for protein synthesis and cell growth, and it plays a critical role in maintaining the integrity of the immune system and respiratory cells during inflammation mucosal resistance.²
Zinc can possibly be protective against COVID symptoms, specifically for those at risk, by reducing inflammation, aiding in breaking up and clearing mucus build up, and modulating the immune system’s response. However, more isolated studies must be done to confirm its effects. When I say isolated, I am referring to studies that do not supplement with other nutrients simultaneously because it would be impossible to determine which nutrients had a positive, negative, or no effect on the patients. Zinc dosing must be the independent variable in future treatment studies.
So how do we protect ourselves against zinc deficiency?
According to the USDA, “the recommended dietary allowance (RDA) for adult men and women is 11 mg/day and 8 mg/day of zinc, respectively”. Like most other vitamins and minerals, zinc can easily be obtained through the diet and/or a multivitamin.
Dietary sources of bioavailable zinc include:
- Organ meats
- Enriched breakfast cereals
Bioavailable means that your body can appropriately and effectively digest, absorb, and process said nutrient. Zinc may also be found in whole grains and legumes, but the zinc is not as abundant or bioavailable in these foods. With that said, since quality zinc is mostly found in animal-sourced foods, those who are vegan may need to supplement to specifically address this lack of mineral absoprtion.
The Upper Limit (UL) for zinc is 40mg/day. However…
Supplementation with doses of zinc in excess of the UL is effective to reduce the duration of common cold symptoms. The use of zinc at daily doses of 50 to 180 mg for one to two weeks has not resulted in serious side effects.³
Just like vitamin C, zinc has been shown to alleviate cold and flu symptoms, which makes sense because these effect the respiratory system. The long-term supplementation of zinc can lead to copper deficiency, but this is not common. Please consult with your physician or child’s primary care pediatric physician before supplementing with zinc.
To wrap up the COVID & Nutrition series…
While vitamin C, vitamin D, and zinc can all arm the body’s immune system with virus weaponry, these nutrients do not provide immunity or prevention of contracting this virus. They can alleviate the severity of signs and symptoms, as well as the duration of an infection should one ensue. Please consult with your doctor before deciding to supplement. Food and drug interactions may occur for those with conditions or taking herbal remedies or medications.
Keep in mind that eating a well-balanced and nutrient-dense diet can set you up for an improved health outlook. While I do not want to condone using the phrase, “boosting your immune system”, eating foods or supplementing with vitamin C, vitamin D, and/or zinc can potentially alleviate symptoms associated with the cold, flu, and respiratory infections. Stay safe, and be happy and well, my friends!
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Photo: HOTZE Health & Wellness Center.; 2017. https://www.hotzehwc.com/2017/07/foods-boost-testosterone/. Accessed May 21, 2020.
1. Wessells KR, Brown KH. Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting. PLoS One. 2012;7(11):e50568. doi:10.1371/journal.pone.0050568
2. Rerksuppaphol S, Rerksuppaphol L. A randomized controlled trial of zinc supplementation in the treatment of acute respiratory tract infection in Thai children. Pediatric Reports. 2019;11(2). doi:10.4081/pr.2019.7954
3. Zinc. Linus Pauling Institute. https://lpi.oregonstate.edu/mic/minerals/zinc. Published January 1, 2020. Accessed May 21, 2020.