What is Vitamin C and what does it do in the body?

Vitamin C, or ascorbic acid, is an essential nutrient, meaning that our body does not produce it on its own and it must be obtained from the diet. Vitamin C is only found in fruits and vegetables and it is highest in fresh, uncooked food. It is also one of the least stable vitamins, and cooking can destroy much of this vitamin in foods. 

Vitamin C is readily absorbed from the intestines, normally around 80-90% of what is ingested through food. It is used up by the body in about 2 hours and then is usually removed from the blood in around 3-4 hours. Some vitamin C is stored in the body, mainly in organs with high metabolic activity such as the adrenal glands, the pituitary gland, the brain, the eyes, the ovaries, and the testes. This stored vitamin C totals around 30mg per pound of body weight. Around 200mg of dietary intake a day is needed to maintain body stores, and more is needed if you smoke, drink alcohol, are under stress, have allergies, are elderly, or have diabetes. 

 

 

In the body, vitamin C is a required cofactor for collagen production. Vitamin C works as a coenzyme to convert proline and lysine to hydroxyproline and hydroxylysine, both important to the structure of collagen. Collagen, and therefore vitamin C, is needed to give support and shape to the body, to help wounds heal, and to maintain healthy blood vessels. 

 

 

Vitamin C also plays a role in the metabolism of tyrosine, folic acid, and tryptophan. Vitamin C is needed to convert tryptophan into 5-HTP, which is the precursor to serotonin. Vitamin C also helps convert folic acid into its active form, tetrahydrofolic acid. Tyrosine needs vitamin C to form the neurotransmitters dopamine and norepinephrine.

Vitamin C also stimulates adrenal function and the release of epinephrine (adrenaline) and norepinephrine, the stress hormones. Prolonged stress can thus deplete vitamin C levels in the adrenals and in the blood. Vitamin C is also needed for thyroid hormone production, and cholesterol metabolism by increasing its elimination. 

Vitamin C is also a powerful antioxidant, meaning it helps prevent the oxidation of water-soluble molecules that would otherwise create free radicals, which can lead to cellular injury and disease. The recycling of vitamin C between its reduced form, ascorbate, and oxidized form, ascorbyl radical, is important for maintaining the body’s supply of vitamin E. It is also needed for the regeneration of glutathione. Vitamin C also indirectly protects Vitamin A, and some of the B vitamins from oxidation. 

 

 

Vitamin C is also a detoxifier and can reduce the side effects of drugs such as cortisone, aspirin, and insulin. It may also reduce the toxicity of heavy metals such as lead, mercury, and arsenic. 

Vitamin C has also been shown to stimulate the immune system. This paired with its antioxidant function may help in the prevention and treatment of infection and disease. Vitamin C may activate neutrophils (a type of white blood cell), it may increase the production of lymphocytes, which are important for antibody production and in coordinating cellular immune functions. In high amounts, Vitamin C may increase interferon production, which can activate the immune response to viruses. It may also decrease histamine production, which makes it useful for allergies. 

 

What are some causes of Vitamin C deficiency?

Vitamin C is used up more rapidly under stressful conditions, with alcohol use, and with smoking. Other conditions and substances that either reduce absorption or increase utilization of Vitamin C include fever, viral illness, antibiotics, cortisone, aspirin and other pain medications, environmental toxins like DDT, petroleum products, and carbon monoxide, exposure to heavy metals, and sulfa antibiotics, which increase elimination of vitamin C from the body by 200-300%. Smokers with poor diets and people with inflammatory bowel disease are more likely to have lower vitamin C levels in their blood. 

Scurvy is the disease that results from extreme vitamin C deficiency. It is a disease characterized by lack of energy, gum inflammation, tooth decay, and bleeding problems. In the 1700s, researcher James Lind discovered that lemon juice could cure and prevent scurvy, so lemons and limes were given to the British Navy sailors daily. Other cultures used powdered rose hips, acerola cherries, or spruce needles, usually as teas, to prevent scurvy. 

 

 

There is a type of scurvy called “rebound scurvy” that occurs when a mother takes high levels of vitamin C (at least 2-3 grams) while pregnant. Vitamin C crosses the placenta, so the baby can get used to higher vitamin C levels in utero and thus feel deficient after birth if they are not breastfed by the mother taking the same amount of vitamin C as she took during pregnancy. This is not a huge concern since the mother simply needs to continue taking vitamin C or the baby can be supplemented with liquid vitamin C. 

Early signs of deficiency include poor resistance to infection, very slow wound healing, easy brusiing, tiny hemorrhages in the skin, general weakness, loss of appetite, and poor digestion. With worse deficiency, symptoms can include nosebleeds, sore and bleeding gums, anemia, joint tenderness and swelling, mouth ulcers, loose teeth, and shortness of breath. 

What is Vitamin C used for?

Vitamin C is used for the prevention and treatment of the common cold and flu. It produces a positive immunological response to help the body fight bacteria and viruses. Vitamin C also helps counteract the side effects of cortisone therapy and may thus counteract the decreased cellular immunity experienced with immune suppressive drugs. Since vitamin C supports adrenal function and the production of adrenal hormones epinephrine and norepinephrine, it can help the body handle infections and stress. For a little more detail on vitamin C related to stress and digestion, check out our blog post: Digestion 101-Physio and Pathophysiology-Part I. Its adrenal supporting function as well as its thyroid support through stimulating the production of T4, a thyroid hormone, may make vitamin C helpful for problems of fatigue and slow metabolism. 

 

 

Due to vitamin C’s role in immunity, its antioxidant effects, its role in adrenal support, and its role in collagen production, vitamin C may be helpful in treating a wide range of viral, bacterial, and fungal infections as well as inflammatory problems. Vitamin C has been used successfully for viral conditions such as colds, flus, hepatitis, herpes simplex infections, mononucleosis, measles, and shingles. Vitamin C can also be used to support problems due to general inflammation from microorganisms, irritants, and decreased resistance such as cystitis, bronchitis, prostatitis, bursitis, osteo- and rheumatoid arthritis, and some chronic skin problems. Regarding arthritis, Vitamin C may improve the integrity of membranes in joints. In gout, vitamin C may improve the elimination of uric acid through the kidneys.

Vitamin C may also be useful for relief of back pain and pain from inflamed vertebral disks, as well as the inflammatory pain that is sometimes associated with rigorous exercise. 

Vitamin C may be useful for asthma because it may relieve the bronchospasm caused by noxious stimuli or when a tight-chested feeling is experienced during exercise. 

Vitamin C’s relation to collagen means that it may support the body cells and tissues to bring more rapid healing to injured or aging tissue. It is thus used for problems of rapid aging, burns, fracture healing, bedsores, and other skin ulcers as well as to speed wound healing after injury or surgery. It is recommended to take vitamin C before and after the surgery to accelerate healing. Vitamin C is also recommended pre and post surgery because it supports the adrenals and immune response to help the body defend against infection, and improve the ability to handle the stress of the surgery. Peptic ulcers also appear to heal more rapidly with vitamin C supplementation and can have great benefits. To read more on peptic ulcers and glutamine, see our glutamine monograph. 

Vitamin C can also be used to aid those withdrawing from drug addiction to substances such as narcotics and alcohol as well as nicotine, caffeine, and sugar. High levels of vitamin C may decrease withdrawal symptoms from these substances and increase the appetite and feeling of well-being. Thus, vitamin C may also be helpful with depression and other mental problems associated with detoxification during withdrawal. Vitamin C can also reduce the effects of pollution through its antioxidant effects, detoxifying effect, and adrenal and immune support. 

Vitamin C can also support constipation because it is a natural laxative. Vitamin C also may support iron-deficiency anemia because vitamin C aids in the absorption of iron in the gastrointestinal tract. In diabetes, vitamin C may support the utilization of blood sugar to support healthy blood sugar levels. 

 

 

 

Vitamin C may have a role in the prevention and treatment of atherosclerosis and thus in reducing the risks of heart disease. Vitamin C has been shown to reduce platelet aggregation, which can reduce the formation of plaque and clots. It also has a triglyceride and cholesterol reducing effect and may help to raise the HDL as well. 

Although there has not been significant enough research on the efficacy of Vitamin C and cancer treatment, the studies conducted thus far and the research into the role of vitamin C in some cancer pathways may make vitamin C a promising addition to a cancer support program. Additionally, its antioxidant, immune supportive, interferon support, and tissue health and healing support may make it a positive influence in cancer treatment and prevention. 

Vitamin C can be used to support symptoms of tinnitus, especially somatic tinnitus, which is connected to physical movement or musculoskeletal tissues. To read more about tinnitus and Vitamin C’s potential role in symptom management, check out our blog post: Tinnitus. 

Vitamin C may also help to prevent eye diseases. Vitamin C may prevent age-related macular degeneration from worsening. Some studies have shown that people with higher levels of vitamin C have a lower risk of developing cataracts. 

 

 

Vitamin C, especially when taken with flavonoids, can be helpful for people who are prone to bruising because vitamin C helps strengthen the blood vessels. Flavonoids, which will be discussed in the forms of vitamin C section as well, help enhance the benefits of vitamin C through improving bioavailability and supporting its antioxidant and anti-inflammatory effects. Flavonoids also help strengthen capillaries, which may help reduce bruising. 

Vitamin C may also be useful for acne due to its anti-inflammatory properties. Vitamin C may also reduce cutaneous lipid peroxidation and P. acnes replication. 

Other clinical uses of vitamin C can include anemia, arthritis, asthma, atherosclerosis, bruising, bursitis, cancer prevention, cataract prevention, cervical dysplasia, chemical exposure, colds, depression, diabetes, fatigue, flu, gallbladder disease, gingivitis, glaucoma, gout, hepatitis, herpes infections, high cholesterol and triglycerides, hypertension, immune suppression, infertility, peptic ulcers, periodontal disease, skin ulcers, surgery recovery, and varicose veins. 

What are the available forms of Vitamin C?

Vitamin C with bioflavanoids is a form of vitamin C that includes bioflavonoids. Bioflavonoids, also known as Vitamin P, are usually found in the same foods as vitamin C and are its water-soluble companions. Natural forms of vitamin C with bioflavonoids have been shown to be more effective than synthetic forms of vitamin C without bioflavonoids in equivalent amounts. Bioflavonoids were named vitamin P because they improve the capillary lining’s permeability and integrity, including the passage of oxygen, carbon dioxide, and nutrients through the capillary walls. 

 

 

 

Bioflavonoids help in the absorption of vitamin C and protect the vitamin C molecule from oxidation to improve and prolong its functioning in the body. Thus, bioflavonoids are also involved in maintaining the health of collagen. Bioflavanoids may also help reduce the amount of histamine released from cells. Bioflavanoids are mainly used to increase the bioavailability and efficacy of vitamin C. By themselves, they are supplemented for problems where improved capillary strength is needed as well as for asthma, allergies, bursitis, arthritis, eye problems secondary to diabetes, and as protection from the effects of radiation. 

Options for Vitamin C with flavonoids include Vitamin C with Flavonoids Thorne, and Bio C Complete Arcana. 

The Bio C Complete Arcana is also a buffered form of vitamin C. Buffered vitamin C means that it comes with minerals that help buffer the digestive effects that can affect people when higher doses of vitamin C are taken. Essentially, buffered vitamin C is easier on the digestive system. A tablet option for this form is Ultra Potent C Metagenics. A powder option for buffered Vitamin C is Buffered C Powder Thorne. 

Another form is Liposomal Vitamin C. This is vitamin C covered in a phospholipid complex to help reduce the digestive issues that can be associated with vitamin C intake, and to increase the bioavailability of the Vitamin C. Options for Liposomal vitamin C include Liposomal Vitamin C Dr. Mercola for a capsule form, and Vitamin C Liposomal Quicksilver for a liquid form. 

For a food based vitamin C, try Amla-C Professional Health Products. Amla berry naturally has a high content of vitamin C and it also contains naturally occurring bioflavonoids. 

Another option for vitamin C combined with bioflavonoids and other ingredients for specific allergy support is Aller-C Vital Nutrients. This type of vitamin C is combined with bioflavonoids, isoquercetin, and bromelain to help combat histamine in the body. 

Since vitamin C is used up every 2 hours and takes 3-4 hours to be removed from the blood, it is suggested to take vitamin C supplements at 4-hour intervals rather than once a day. 

What are food sources of Vitamin C?

The best-known food sources of vitamin C are citrus fruits, including oranges, lemons, limes, tangerines, and grapefruits. The fruits with the highest content of vitamin C are citrus fruits, rose hips, acerola cherries, papayas, cantaloupes, and strawberries. Vegetable sources include red and green bell peppers, broccoli, Brussels sprouts, tomatoes, asparagus, parsley, dark leafy greens, and cabbage. Sprouts can be a good source during winter and early spring when not as many fresh fruits and vegetables are available. Other sources include capsicum, kiwis, black currants, sweet potato, red currants, pineapple, mangoes, satsumas, turnips, artichokes, avocados, leeks, okra, peas, tomatoes, broad beans, parsnips, and rhubarb. 

 

What are contraindications of Vitamin C?
Possible contraindications include kidney disease patients taking medications with aluminum such as phosphate binders because vitamin C can increase the absorption of aluminum from aluminum containing medications. Vitamin C’s antioxidant effect may reduce the effect of chemotherapy drugs. Taking vitamin C with oral contraceptives or hormone replacement therapy may increase estrogen levels. Vitamin C could reduce the effect of warfarin, statins, niacin, and protease inhibitors.

 

What are the side effects of taking Vitamin C?

Vitamin C is not stored appreciably in the body and most excess amounts can be eliminated rapidly through the urine. However, taking over 10 grams of vitamin C daily can lead to some side effects. Diarrhea is the most common side effect and usually the first sign that the body is saturated with Vitamin C. Other side effects include nausea, dysuria (burning upon urination), and skin sensitivities. Hemolysis of red blood cells could also occur with very high amounts of vitamin C. 

There is some concern that higher levels of vitamin C intake could cause kidney stones, specifically calcium oxalate stones since increased oxalic acid clearance through the kidneys occurs with vitamin C metabolism. However, this is very rare and there is little research evidence to support this. However, if you are prone to kidney stones or gout, you may want to exercise caution with Vitamin C. You can also supplement magnesium in amounts between half and equal to that of calcium intake to reduce the risk for calcium based stones. 

 

 

References

Haas, E.M. (2006). Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine: 21st Edition. Ten Speed Press. 

Hechtman, Leah. (2019). Clinical Naturopathic Medicine: Second Edition. Elsevier.

MayoClinic Staff. (2023, Aug 10). Vitamin C. MayoClinic. https://www.mayoclinic.org/drugs-supplements-vitamin-c/art-20363932

Murray, M.T. & Pizzorno, J. (2021). Textbook of Natural Medicine: Fifth Edition. Elsevier. 

Murray, M.T. & Pizzorno, J. (2012). The Encyclopedia of Natural Medicine: Third Edition. Atria. 

Mussa, A., Mohd Idris, R. A., Ahmed, N., Ahmad, S., Murtadha, A. H., Tengku Din, T. A. D. A. A., Yean, C. Y., Wan Abdul Rahman, W. F., Mat Lazim, N., Uskoković, V., Hajissa, K., Mokhtar, N. F., Mohamud, R., & Hassan, R. (2022). High-Dose Vitamin C for Cancer Therapy. Pharmaceuticals (Basel, Switzerland), 15(6), 711. https://doi.org/10.3390/ph15060711