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NMU 165 – Vitamin C, Neutrophils and NETs in Life-Threatening Respiratory Tract Infections

Nutrition / Natural Medicine Update No 165 (May 28, 2020)

with Dr. James Meschino


Topic: Vitamin C, Neutrophils and NETs in Life-Threatening Respiratory Tract Infections

Source: Multiple Peer-reviewed Medical and Scientific Journals (see references below)


In this update, I want to give you some background as to the importance of vitamin C in supporting our immune cells, called neutrophils, as they go about the business of protecting us from developing respiratory tract infections and their potential complications. Under normal conditions, neutrophils are the most numerous circulating immune cells in the bloodstream. They are part of the body’s Innate immune system, which means that throughout millions of years of evolution neutrophils have evolved not to require any priming to fight and destroy incoming disease-causing viruses or bacteria. They immediately recognize them as a threat to the body and they spring into action immediately to destroy these potential invaders. They have the inherent ability to migrate to tissues where hostile viruses or bacteria are present whereupon, they engulf and destroy dangerous viruses and bacteria on contact (including coronaviruses). How do they do this? After ingesting or engulfing the virus, neutrophils secrete anti-microbial agents that either pierce a hole through the virus to cause it to burst or they kill the virus by generating virus and bacteria-killing free radicals.

Now here is the catch. To effectively migrate to the location where hostile viruses are present in the body (i.e. the lungs) neutrophils require ample amounts of vitamin C. They also require ample amounts of vitamin C to ingest viruses and to generate the free radicals they use to kill viruses and bacteria. As such, neutrophils have special pumps in their outer layer skin (membrane) that literally pump vitamin C from the bloodstream into the interior of the neutrophil.

As a result, neutrophil concentrations of vitamin C are higher than blood levels of vitamin C, as neutrophils largely depend on vitamin C for their infection-fighting capabilities. Studies show that 200 mg per day of vitamin C ingestion is enough to optimize neutrophil vitamin C levels in young healthy people, which maintains a minimum blood vitamin C level of 50umol/L (and that is the vitamin C blood level you want to maintain over your lifetime – at or above 50umol/L). In individuals over 60, it appears that 1000 mg per day is required (500 mg in two divided doses is best) During a respiratory tract infection neutrophil vitamin C is depleted very rapidly and at least 2,000 mg per day (divided dosages of 500 mg per dose) is required to maintain more optimal neutrophil function to help fight a viral or bacterial infection. As the scientific literature states, “gram doses of vitamin C are required once an infection has taken hold, due to increased requirements for the vitamin. Gram doses of oral vitamin C have been shown to provide peak plasma ascorbate concentrations of greater than 150 µmol/L”, which is desirable in cases where a person is fighting an infection. This can involve daily doses of vitamin C of 4,000 to 6,000 mg per day, or higher. If vitamin C is not replenished via oral supplementation or via intravenous means, neutrophils begin to contribute to the infectious process as much as they try to fight the infection.

When neutrophils are not provided with adequate amounts of vitamin C, they release into the bloodstream fibrous strands called NETs (Neutrophil extravascular traps). Although NET’s can also trap and destroy viruses, they also trigger other immune cells to create a cytokine storm, which greatly increases the inflammatory response that often leads to organ failure and the formation of abnormal blood clots and hypercoagulation of the blood. These are often the final and fatal steps that occur in advanced respiratory infections and sepsis that causes organ failure throughout the body, especially impacting the heart, kidney, and liver. Some recent studies have shown that providing patients with sepsis with vitamin C supplementation or intravenous vitamin C, in gram doses, has shown promising results in preventing death in a significant number of patients, vs the control group.

In my view, it makes no sense to wait until you have an advanced respiratory tract infection or sepsis before considering vitamin C therapy. To optimize neutrophil function and to prevent the formation of NETs from neutrophils it makes sense to support your neutrophil function by ingesting 200-1,000 mg per day, at least, if you are currently healthy. At the first signs of a respiratory tract infection, regardless of the cause, ingesting 500 mg of vitamin C, 4 times per day, as a minimum dosage, has been shown to support neutrophil function in fighting infections and help prevent the secretion of NETs into the circulation, which can otherwise trigger a life-threatening cytokine storm, blood clots, and subsequent organ failure and death.

I have included the scientific references to support these facts in the text below. When it comes to supporting critically important neutrophil function, optimal vitamin C intake is the key.


1. Bozonet SM and Carr AC. The role of physiological vitamin C concentrations on key functions of neutrophils isolated from healthy individuals. Nutrients June 2019. 11,1363.









Eat Smart, Live Well, Look Great,

Dr. Meschino

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