Vitamin C (Ascorbic Acid); Impact on Health and Cancer

Vitamin C or ascorbic acid.  One of the most readily recognized nutrients likely on the face of the earth, associated with prevention and treatment of the common cold.  However, could there be more to this nutrient?  Is vitamin C more important and possibly more protective to your overall health than what we have been led to believe?  Let’s take a look as I reminisce on my early days of research and vitamin C.

Vitamin C, Health, and Cancer
Vitamin C, Health, and Cancer

Vitamin C is a substance that we are all familiar with and often the first fruit acknowledged is the orange.  In the days of pirates and ocean voyages for extended periods of time, the ship crew would often succumb to a disease called Scurvy, which is due to a vitamin C deficiency.  In later voyages, in order to prevent the disease, ships were often readily stocked with various fruits in order to maintain adequate intake by the crew.  Despite the low recommended levels for daily consumption to prevent Scurvy, this vitamin poses much potential for overall health and possible disease prevention.  The concept of ingesting larger doses on a daily basis was explored by many physicians in the past with one notable individual being a chemist by the name of Linus Pauling.

Vitamin C is created internally in most animal and plant species with the exception of humans, apes, monkey, bats, guinea pigs and some birds and fish.  It is however, required by all animals and plants in several enzymatic and metabolic reactions, whether if it is synthesized or not.  If it is not synthesized, as in the case of humans, consumption through the diet or via supplementation is essential.  The one exception to this is in animals that do naturally synthesize the vitamin, is the concept of supply and demand, as in the case of critical disease or injury. In those situations, essentially supply is not meeting demand and the disease is essentially consuming more vitamin C that can be produced.  This idea holds true for humans and primates as well, despite dietary or oral supplementation.

Ascorbic Acid (vitamin C) acts as a reducing agent or antioxidant in the body, helping to neutralize free radicals.  It is also a cofactor in the formation of collagen, which is a vital component of almost every supporting tissue in our body from the skin, tendons and extracellular matrix.  Due to its relation to collagen formation, vitamin C is essential for proper wound healing and tissue repair. Vitamin C has also been shown to potentially enhance overall immune function and even impact circulating levels of histamines, as seen in allergies.

The RDA for vitamin C is 90 mg per day, while the dose needed to eliminate Scurvy is 45 mg.  It has been noted that intakes of between 100-200 mg daily are associated with reduced risk of cardiovascular disease, cancer and cataracts in people. Oral absorption is generally thought to be about 70-90% at normal levels, but actually drops to around 30% with increasing doses. Higher doses of vitamin C consumption have been associated with a decreased risk of cardiovascular disease, overall reduced risk of all risk mortality and increased life expectancy.

Vitamin C when taken orally has limitations on peak blood levels due to absorption, tissue accumulation and excretion.  In other cases, there are limitations on blood levels due to increased demands as seen with certain diseases. Oral consumption is generally limited to 1-3 grams at a time, due to limited absorption and saturation of the intestinal tissue, which causes an osmotic type of diarrhea in most patients.  High end consumption of vitamin C should be cautiously in those human patients with a genetic condition called glucose 6 phosphate deficiency and in patients with nocturnal hemoglobinuria.  There is also a very low risk of oxalate stone formation in those predisposed to the condition and a potential for worsening of iron overload in patients with hemochromatosis or those that receive constant blood transfusions.

Linus Pauling was one of the most noted researchers regarding ‘mega dose’ vitamin C therapy and advocated doses ranging from daily intake of 1000 mg to over 50 grams per day.  His recommendation was to split the daily dose into multiple doses, in order to maximize absorption over time.  Pauling was an advocate for tailored dosing regimens for each patient, dependent on their condition, which was determined by bowel tolerance.  The theory was that once the patient developed the osmotic diarrhea or abdominal distress associated with complete tissue saturation, he recommended that they then reduce that dose until the clinical signs were eliminated, which then determined their daily needs.  For some patients, this dose was very high, while in others it was much lower.  In cases of more serious disease, such as with cancer, often the dose was found to be quite high.  The explanation was often related to be due to excessive consumption by the body by the disease course itself, dictating an increased need.

Therapeutic Value of Vitamin C

Vitamin C is involved in many cellular and enzymatic processes within the bodies of every animal species, including humans, pets and horses.  As mentioned above, it is a potent antioxidant helping to control oxidative stress and the damage inflicted upon cellular DNA.  It is also invaluable for production of collagen, which helps in maintaining tissue strength and wound repair. Vitamin C is also helpful for maintaining a healthy immune response.

Vitamin C has been found helpful in many aspects during and after surgical procedures to help the patient to recover from oxidative damage and encourage faster wound healing. As a veterinarian, I have noted that many of our surgical patients underwent an oxidative imbalance during the course of the procedure, in which free radical levels became elevated with antioxidant reserves low or depleted.  I have found that if we supplemented with vitamin C before, during and after the procedure, the recovery rate was much better for the patient.  Despite this important observation, most of my colleagues were disinterested.

Increased daily intakes of vitamin C, ranging from 200-500 mg /day in people were associated with a lower risk and mortality associated with cardiovascular disease.  Vitamin C, taken in higher doses of 500-2,000 mg /day were also associated with a reduced total cholesterol, LDL and triglycerides, however HDL levels were not impacted.  Higher serum levels of vitamin C were also associated with a reduced risk of stroke. Higher daily intakes of Vitamin C have also been shown to help dilate blood vessels, which may improve cardiac tissue circulation and potentially reduce blood pressures.

Vitamin C therapy brings new possibilities into cancer management.  Malignant forms of cancer often spread or metastasize through destruction of the extracellular tissue, which contains collagen.  Another aspect to cancer is that an enzyme, hyaluronidase, is often increased, which allows for collagen destruction.  Vitamin C helps to rebuild collagen and support the extracellular tissue, but it has also been shown to inhibit hyaluronidase.  High blood levels of ascorbate have also been shown to be toxic to various cancer cell lines through the formation of hydrogen peroxide (H2O2) and formation of free radicals, which damage and kill the cancer cells.

According to the Linus Pauling Institute, in the Nurse’s Health Study, pre-menopausal women with a family history of breast cancer that consumed an average of 205 mg/day of vitamin C, had a 63% reduced risk of breast cancer.  In the Swedish Mammography Cohort, overweight women who consumed an average of 110 mg/day had a 39% lower risk of breast cancer as compared to the same group that consumed an average of 31 mg/day.

Other areas that has shown some interesting data include the use in other forms of cancer including lymphoma, stomach, colon and bladder cancer.  Many of these forms of cancer, including stomach and bladder are often associated with carcinogenic nitrosamine compounds that are consumed via the diet and lifestyle factors.  Vitamin C has been shown to inhibit the formation and activity of nitrosamine compounds, thus providing a means of protection against the cellular damage induced.  In other areas of research, higher daily intakes of vitamin C have been connected with a decreased incidence of cataract formation and reduction of the clinical signs of gout, due to lowering of serum Uric Acid levels.  Higher serum levels of vitamin C have also been shown to be beneficial in cases of osteoarthritis due to increased collagen deposition, reduction of proteoglycan degradation and even reduction of pain.

It is to be noted that routine usage of Estrogen based birth control medications and aspirin have been shown to be associated with lowered serum levels of vitamin C, thus creating a need for supplementation especially in those individuals.

Intravenous High Dose Vitamin C Therapy:

One means of getting around the oral limitations and bioavailability is through the administration of vitamin C or ascorbate through intravenous injection.  IV vitamin C therapy is able to achieve blood levels 70x that of oral dosing due to bypassing the limitations on absorption.

High dose vitamin C therapy has been explored for many years and initially became popular with physician Fred Klenner, based out of North Carolina, beginning back in the 1940’s.  Dr. Klenner reported using doses up to 700 mg/kg of bodyweight in humans to help manage many types of physical ailments ranging from allergic reactions, to shock to cancer, all with good results with improved patient outcome.

The Myer’s cocktail was soon a popular treatment regimen and still used today in many non-traditional practices.  This formulation often delivers high doses of vitamin C and other macronutrients in an IV solution to the patient over a course of a few hours.

Intravenous vitamin C doses can range from 10-500 grams, dependent on the patient size and condition being managed.  As you can see, the dose level is much higher than those used traditionally via the oral route.  Through the use of high doses of vitamin C intravenously, one is able to achieve very high serum levels that can demonstrate profound effects on cellular function.  In terms of cancer therapy, there are many reports of IV vitamin C usage with good outcomes in terms of patient recovery and overall health.  The high doses achieved have been shown to actually have a pro-oxidant effect, instead of antioxidant impact, targeting various cancer cells and increasing cell death but not impacting normal, healthy cells.

As a veterinarian, we often used high dose IV vitamin C therapy in our patients, including pets and horses.  For a short period of time, we followed our companion animal surgical patients and found, through the use of blood assays, that many of these patients became unstable with high levels of free radicals and depleted antioxidant scores.  This finding was more common in older patients, but also found in younger pets undergoing routine procedures.  In the more serious cases, such as acute traumas or other illness, the levels were more noticeable and often correlated with poorer recovery rates and outcomes.  It soon became a normal procedure to administer high dose IV vitamin C to those patients while undergoing a surgical procedure.  In the end, the patients seemed to do much better throughout the procedure but also appeared to recover much easier for the long term with better outcomes.  Those seeking more information on IV vitamin C usage in companion pets can click this link.

All of this information was gathered on a personal interest basis while in private practice with no findings published due to lack of overall interest from the veterinary journals.

As you can hopefully see from this information, Vitamin C is an important nutrient found in the diet at low levels, but can potentially help to impact health when the daily intake is increased. The take home point is that even in those species that do produce vitamin C, there is a supply and demand situation occurring.  In times of severe or chronic illness, supplies can be quickly depleted, which then can negatively impact health.  Through supplementation, levels can be increased and demands can be met with very little risk of toxicity. As with many other nutrients, vitamin C is needed by the body.  If the levels are depleted, then health is at risk on many levels. Despite the species (human, pet or equine), research has shown many benefits to increasing the daily intake of vitamin C.  The ultimate question lies in the dose utilized and based on the bowel tolerance described by Pauling, this is an individual based situation and hard to determine exactly.


All my best,

Tom Schell, D.V.M.

Nouvelle Research, Inc.

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