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Supplements, Vitamins and Coronavirus

Updated: Oct 8, 2021

Covid-19 continues to make headlines and be at the forefront of the conversation on a daily or weekly basis. As time goes on, we learn more about this virus, how it's spread, and what we can do to protect ourselves and others. Unfortunately, because there is still so much to learn, and we're not certain about treating coronavirus, finding answers can prove challenging.


n October of this year, I attended the virtual Food and Nutrition Conference and Expo given by The Academy of Nutrition and Dietetics. I was excited to participate in the session titled "The Role of Nutrition in Supporting the Immune System Relative to Coronavirus," given by Simin Nikbin Meydahi, DVM, Ph.D.

It can be challenging to weed through all of the nutrition information available about how specific vitamins and supplements affect the outcomes once a person has coronavirus. Hence, I wanted to hear about studies that were current and relevant to my clients. The following is a summary of the findings of Dr. Meydahi's work. All of the information and slides were authored by her.

When it comes to immunity, nutrition plays a significant role in improving one's ability to fight disease. It is becoming more critical than ever. Factors such as obesity, aging, and malnutrition impact one's ability to resist infection and virus' severity. According to Dr. Mydan, 13% of the world's population is obese, and 8.5% is over 65. In some developed countries, the obesity rate may be as high as 20% and is expected to reach as high as 40% by 2050. Both aging and obesity can make people more susceptible to disease and impair the response to the vaccine.


Before we get started, I would like to point out that although we know that a deficiency in specific vitamins may contribute to an impaired immune response, providing a higher than adequate vitamin dosage does not mean that it will have the opposite effect. In other words, megadosing on vitamins can be detrimental and does not translate into an improved immune response to disease. I've seen some people recommend a higher than usual dosage of specific vitamins, and I can't entirely agree with that. Stick with the amount you see on the label and eat foods high in that particular nutrient.


Vitamin E supplementation (200 IU) in the elderly has been shown to improve immune system function and improve vaccine efficacy. In other age populations, a larger dose of Vitamin E helped to reduce inflammation and strengthen disease response. The same was also confirmed in the flu virus, cold viruses, and pneumonia. Do you need to supplement? It depends. It is always better to get adequate vitamins from food, but if you fall into a high-risk category for coronavirus, a supplement might be a good idea as long as it's okay with your doctor. The recommended dosage for adults is 15 milligrams per day.


Zinc plays a significant role in immunity, and a deficiency predisposes people to higher rates of infection. Zinc supplementation can improve the response to infection when there is a deficiency. Those in the elderly population with low zinc levels had more pneumonia and prolonged illness duration. All people will benefit from supplementation if levels are low, especially in preventing and fighting respiratory infections. Some studies show zinc supplementation may fight the common cold, but it was dependant on the type of Zinc utilized. Surprisingly, deficiency occurs in young and older adults in both developed and underdeveloped countries. One reason may be that your body doesn't store Zinc, so you need to eat enough every day to ensure you're meeting the daily requirements. Men should be getting 11 mg of Zinc per day, and women require 8 mg. Children, teenagers, and the elderly are the most at risk of being deficient. Meat, nuts, shellfish, legumes, and seeds are high zinc foods, and if you're lacking or don't get enough of these foods daily, a supplement may be a good idea if approved by your doctor.

Vitamin D

Low vitamin D is linked to a higher risk of upper respiratory tract infections, but more research needs to be done in this area to prove this definitively. However, this vitamin does help increase antibacterial proteins and potentially reduce the risk of autoimmune disease. Because vitamin D is synthesized in the skin from sunlight, and I happen to live in the upper Midwest where the sun doesn't come out much in the winter, I recommend a supplement to many of my clients, especially if they don't eat dairy foods. The recommended amount is up to 2000 I.U. Per day for adults. Opt for a vitamin D3 supplement that you can get over the counter.

One study indicated that people with severe covid-19 may have a lower level of vitamin D and may benefit from supplementation. However, the number of subjects was small and other factors might have been at play. More studies need to be done, and I'm sure we'll see more research in this area as we continue to examine effective treatments for covid.

Vitamin C

This vitamin is essential in adequate supply to initiate an effective immune response. Vitamin C is a water-soluble vitamin present in many of the common foods we eat, especially citrus fruit. It appears that supplementation may be beneficial in those with low vitamin c status. Other factors that could increase the need for vitamin C are stress, smoking, and other diseases. There is not enough evidence for vitamin C supplementation to prevent pneumonia and other respiratory infections in the overall population. However, if one doesn't get enough from food, a supplement may aid in fighting coronavirus. The recommended daily amount is about 90 milligrams per day.

Some reports indicate IV vitamin C may help those with Covid 19, and clinical trials are currently underway in China and Italy, and some doctors use them in the United States. No published studies are indicating its effectiveness; however, there has been some success. This is an exciting research area and may be one of the future treatments for the virus. We'll have to wait and see but in the meantime, get your vitamin C daily,


Quercetin is a plant flavonol and is found in many fruits, vegetables, leaves, seeds, grains, onions, and kale. You can buy it in supplement form over the counter. Computer modeling identified Quercetin as an antagonist to coronavirus and may also have anti-inflammatory effects, especially those relevant to respiratory infection. I recommend a supplement in the standard dosage to those who don't eat a diet high in the foods listed.


Obesity can lower the T-cell response while increasing the inflammatory response when infected with the coronavirus. Obesity may impair the immune response to the flu virus as well. Patients with higher BMI had a significantly higher likelihood of going on a ventilator and experience much more severity with coronavirus.

As obesity rates continue to rise in the U.S., this should be a wake-up call that we need to do our best to address this growing problem. Several experts in obesity medicine are doing a great job exploring new research into this area, and we have learned a lot in the last few years. Even with a 5% weight reduction, clinically meaningful results may follow. Interestingly, fruits and vegetable supplementation (8-9 servings ) mitigates obesity-induced inflammation and T-cell (immune cells) suppression. This is more proof that a plant-based, high produce diet which follows the Mediterranean style of eating may have a positive health impact.

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