Vitamins are an integral component of our health and longevity. Their function in biochemical and physiological processes helps ensure we maintain energy, protection from illness, and well-being throughout our lifetime. 

Since the emergence of COVID-19, the search for a medication that minimizes viral symptoms has become the forefront of research. This brings the fighting power of vitamin C into the spotlight.  

Over the years, therapeutic interventions have been tested to assess the role of vitamin C in people suffering from certain conditions. This introduced the concept of high dosing vitamin C for the treatment of diabetes, atherosclerosis, the common cold, stroke, heart disease, chronic fatigue, fibromyalgia and even cancer (1 ). And now brings into question the application of vitamin C to treat COVID-19 positive patients.

What is Vitamin C?

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that we require to maintain adequate health and fight off infection and illness. It helps in the formation of cartilage, absorption of iron, wound healing, and contributing to our immune health.

As an essential nutrient that cannot be synthesized within our bodies, certain dietary considerations must be in place. Some high dietary sources include citrus fruits, green leafy vegetables, red and green peppers, strawberries, cantaloupe, and fortified cereals. For those who are not getting their daily requirements through diet alone, the National Institute of Health has recommended supplementing 90 mg/day for men and 75 mg/day for women (2) – more on this in a moment!

How Vitamin C Influences Our Immune Health 

Among all the vitamins and minerals necessary for maintaining adequate health, vitamin C is the key player in proper immune functioning. It’s fighting power against illness and infection is accomplished in the following 4 ways:

 

1. Vitamin C as an Antioxidant 

Free radicals, which are formed when oxygen splits into single atoms with unpaired electrons, can be incredibly harmful to our health. They’re linked to conditions such as cancer, atherosclerosis, Alzheimer’s Disease, Parkinson’s Disease, etc. These reactive oxygen species accumulate in our bodies from metabolism, and exposure to air pollution, pesticides, toxic metals and ultraviolet light, causing oxidative stress and chronic inflammation in the body (3).

 

Vitamin C functions as an antioxidant by donating an electron to free radicals to neutralize them. Balancing the number of free radicals to antioxidants helps to reduce this oxidative damage to the cells throughout our bodies. This neutralization helps to support our bodies’ natural defences and minimizes the inflammation and damaging effects of oxidative stress (4). 

2. Vitamin C as a Cofactor 

The activity of an enzyme can be optimized under certain conditions. For instance, having the support of a cofactor during a reaction can help to stabilize the biochemical transformation of the product and increase the overall reaction rate. 

As a cofactor, vitamin C activates the enzyme that builds collagen – a protein found in skin, bones, and connective tissue – providing strength and protection for our body against injury. It also assists in the synthesis of certain hormones that help control the cardiovascular response to infections (5). 

3. Vitamin C as a Mast Cell Stabilizer

As a vitamin closely linked to our immune system, it plays a role in controlling certain white blood cells. One of which include mast cells, which help to protect our bodies from illness and infection. These cells release an organic compound known as histamine. Upon activation, histamine boosts our local immune response by causing inflammation in the area of need. A common trigger of mast cell activation is the presence of virus (but not limited to that). Unfortunately, disorders involving over-production or over-activation of mast cells leads to too frequent or too high release of its products (oftentimes leading to histamine intolerance). Mast cells line the respiratory tract, and when activated mucous and swelling can occur. There are mast cells and histamine receptors throughout the body, so that symptoms may be evident outside of the respiratory tract as well. Mast cells are present in the brain, GI tract and skin, for example, causing local or more widespread inflammation when histamine is released. Suffice to say an over-reactive immune response may provoke numerous health problems down the road, including chronic inflammatory diseases.

Vitamin C helps to control our immune response through mast cell stabilization. By limiting mast cell activation in the lungs and upper respiratory tract , vitamin C decreases bronchial hypersensitivity experienced during a common cold, shortens the duration of a cold, minimizes the symptoms experienced during a cold such as sneezing, runny nose, and cough, as well as preventing pneumonia (6).

4. Vitamin C as a General Immune Booster

 

Generally speaking, this essential vitamin plays a crucial role in our immune defences. It’s linked to having a direct effect against infectious agents such as bacteria, viruses, and possibly cancerous cells. It assists in the following ways (7)(8):

– Contributing to our immune defences by supporting and directly stimulation cellular functioning of both the innate and adaptive immune system 

– Supporting epithelial barrier function to prevent pathogen entry, important in gut and respiratory health

– Affects migration of macrophages to areas of infection and/or cell damage 

– Assists white blood cells (such as neutrophils) with the destruction of microbes

– Enhances differentiation and proliferation of B- and T-immunity cells, part of our adaptive immune system. Learn more.

– Required for apoptosis (programmed cell death) and clearance of neutrophils from a site to reduce potential tissue damage

Applications of Vitamin C

 

In order to maximize the benefits that vitamin C provides, taking the required daily dose is only one piece of the puzzle. The other piece relies on our bodies’ capacity to utilize it. The amount of a substance (such as medication, vitamins, or minerals) that enters our circulation when first introduced into the body that has an active effect is known as bioavailability. 

The way we consume vitamin C can make a difference in how much our bodies will absorb and subsequently use it. Let’s check out the top dosing mechanisms of vitamin C and how it influences its effects on our bodies.

Water-Soluble Vitamin C

The most commonly used method for consuming vitamin C is through natural sources in the food we eat. Often times people are not achieving their daily requirements which are where synthetic supplements come in. This can be in the form of powders, chewable tablets, or non-chewable tablets – all of which are water-soluble in nature. Research has discovered a minimal difference in ascorbic acid bioavailability between natural and synthetic versions (9). 

To optimize the amount of vitamin C absorbed and utilized you need to take into consideration two key features:

1. Transporters influence bioavailability.

To sufficiently absorb and utilize Vitamin C, we must rely heavily on the activity of transporters throughout our digestive tract to allow their entry into the bloodstream. However, transporters can become oversaturated when too much of one thing is being metabolized.

2. Saturation depends on health status

Individuals who are healthy and non-smokers are able to achieve sufficient intake through diet alone, provided it contains high quantities of vitamin-rich sources. For the diseased and smoking population, diet alone may be insufficient. This is due to an inadequate recycling process preventing repletion of the Vitamin C, which is a necessary process carried out by red blood cells in humans since we cannot make it the way other mammals can. Also important is presence of much more oxidative stress in these groups, which needs to be dealt with through higher intake often through supplementation (10). RDAs (Recommended Dietary Allowances), as referenced by many, do not provide the full picture and cannot be relied upon in the clinical setting of chronic disease management.

Based on individual needs, some people may require a different dose or method of dosing to optimize their absorption and utilization of vitamin C.

Liposomal Vitamin C

In the effort to improve the bioavailability of certain active drugs, they can be inserted inside a fatty particle known as a liposome. Unlike water-soluble vitamin C, liposomal versions reduce the ascorbic acid break-down in the gastrointestinal tract, slow its release and ultimately enhance its absorption (11). This helps to improve vitamin C bioavailability without compromising its potency. 

When considering this form of supplementation, you should make sure it’s well-sourced. A good product should be able to bind together the lipid and ascorbic acid when exposed to water in the small intestines. This ensures more of the active ingredient is utilized by the body rather than being excreted in the urine. 

Intravenous Vitamin C

Although oral administration of vitamin C is the most common supplementation method, it may be less effective than intravenous (IV) administration, depending on the clinical context. IV administration of ascorbic acid provides 100% bioavailability in the body.

IV vitamin C has been used in cancer treatments in conjunction with chemotherapy, with some disagreement. In high doses of 75-220g, it becomes an oxidant – as opposed to its antioxidant function in lower doses – some say contributing to cancer protection. As an oxidant, vitamin C can interact with oxygen and iron to create hydrogen peroxide (H2O2). This interacts with immune cells to kill foreign pathogens, including potentially cancer cells (12). 

IV dosing has been researched over the years to gain more insight into the benefits of high dose vitamin C, its implications for fighting both bacterial and viral infections, and use in chronic illnesses. The high dose helps to limit cytokine recruitment, which is a characteristic response of Acute Respiratory Distress Syndrome (ARDS) seen in late stages of COVID-19 (13). Overall, it improves physiological function in adults by decreasing oxidative stress (14). 

What does this all mean?

The recent outbreak of COVID-19 has encouraged researchers to shine more light on vitamin C in therapeutic interventions. Its benefits are recognized in many forms of treatment settings. In oral preparations and at lower doses its activity as a powerful antioxidant helps neutralize reactive oxygen species (ROS) which are a byproduct of most infectious agents. When using oral preparations at home, bioavailability into tissue compartments is shown to be enhanced with liposomal versions when compared to water-soluble powders and/or capsules.

The best bioavailability is seen in a clinical setting with IV infusions. Considerations for IV administration can be made for more critical cases. In severe COVID, a treatment every 6 hours for up to 7 days in the ICU setting has been recommended for managing the “cytokine storm” that is involved in ARDS, as mentioned. In other diseases, such as for Fibromyalgia and Chronic Fatigue Syndrome, it may be employed once or twice a week. The Myer’s Cocktail employed by some Functional Medicine physicians, with other micronutrients added, is an example. A key principle then: customizing dose, frequency and route of administration depending on the case at hand, so that Vitamin C in medicine can be applied for a variety of needs.

Taking the initiative to boost your immune system is essential in times of stress and uncertainty. Research continues to reinforce the positive implications of taking vitamin C and although it’s only one of many ways to contribute to a healthy, happy immunity, it’s usually very safe and can be an effective place to start!

PLEASE NOTE: The ingestion of large doses of ascorbic acid is contraindicated in cases of renal insufficiency, chronic hemodialysis patients, unusual forms of iron overload, and oxalate stoneformers. Consult with your physician before proceeding.

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