Is it possible to overdose on Vitamin C?
Questions on what daily intake of ascorbic acid is considered to be an "overdose" come up on a regular basis. While less informed sources dismiss the possibility of a Vitamin C overdose or toxicity based on ascorbic acid being water-soluble, they seem to forget that even water-soluble nutrients interact with other nutritional elements as synergists or antagonists, and as such are capable of enhancing or inhibiting their benefits and functions. Since these interactions are relative to the levels of all the other nutrients Vitamin C interacts with, and since these levels vary from one patient to the next, it is not possible to establish a universal Vitamin C overdose amount, or specific Vitamin C side effects that apply to everyone. At the same time, while the potential to clinically overdose on Vitamin C does exist, it is quite rare and not expected to occur at the 250 to 1,000 mg adult intake level considered average for those that regularly self-supplement.
However, as demonstrated with several examples below, the effect of a regular, daily overdose of Vitamin C is not an acute event as experienced with a deadly, toxic substance, but a gradual change in mineral ratios, or the progressive lowering of other essential elements, which over time can result in the development of moderate to serious medical problems. An acute medical event can still arise though following a substantial Vitamin C overdose, where too much ascorbic acid lowers an already deficient nutrient even more, resulting in acute deficiency symptoms of that nutrient, or where an excessive intake of Vitamin C triggers acute gastrointestinal symptoms. (see bottom of this page for Vitamin C overdose signs and symptoms).
The effect of high doses of Vitamin C on Copper, Zinc, Manganese, and Calcium:
There are individuals whose copper levels are on the low side. Being unaware of the antagonistic effectof Vitamin C on copper, they may feel a cold coming on and start to take a few thousand mgs of Vitamin C,causing copper levels to drop to a point of becoming deficient, and provoking an inflammatory response.
Acute conjunctivitis (Pink eye), or blepharitis (inflamed eyelids) triggered by copper deficiency following ashort course of very high ascorbic acid intake, is a classic example of how taking too much Vitamin C canactually cause, or worsen an infection. Chronic conjunctivitis (or blepharitis) can occur when higher copperstores are gradually depleted following the practice of regularly overdosing on Vitamin C. It can also developsecondary to overdosing on other copper antagonists, such as Sulfur (MSM, glucosamine sulfate), or Zinc.
Nutritional excesses and deficiencies - including Vitamin C overdose - can be one of the less-obvious toestablish non-viral, bacterial, or allergenic causes for inflammatory eye disorders or other medical issues,although higher doses of Vit C & A may be required in the nutritional treatment of infectious conjunctivitis.
In another chronic copper deficiency / Vitamin C overdose example, a young boy was brought into my officeto investigate the reason why his leg bones were soft and becoming increasingly malformed. It turned outthat his father was giving him 2,000 mg of Vitamin C per day from an early age, which resulted in a severe,long-term copper deficiency. Reducing his ascorbic acid intake to more reasonable levels corrected thecondition. 100 mg - 250 mg of Vitamin C is sufficient for most young children to meet basic requirements. Vitamin C lowers Zinc directly, and it lowers it indirectly by supporting Iron absorption, so while a higherintake of ascorbic acid would likely benefit those suffering from some forms of anemia, leukemia, left-sidedovarian cysts, or from prostatitis, the same higher Vitamin C intake would worsen certain liver conditions(hemochromatosis), benign prostatic hypertrophy, or more serious kidney diseases (renal failure). Larger amounts of Vitamin C lower Manganese levels and aid greater insulin production in those capable ofproducing insulin, which may be beneficial for Type II diabetics, but it would worsen those with hypoglycemictendencies that exhibit low sodium, since sodium slows insulin response, so a very high intake of Vitamin Cwould create larger insulin spikes. By lowering manganese, very high doses of Vitamin C also affect (lower)glycogen stores in the liver.
Manganese has some control over the liver's ability to break down estrogen, so too much Vitamin C can affectthe length of the menstrual cycle and worsen low estrogenic-types of PMS. On the other hand, congestiveliver disease, resulting in higher estrogen levels, will benefit from higher doses of Vitamin C by reducing thesymptoms of high estrogenic-types of PMS, while at the same time reducing the risk to develop estrogen-sensitive (estrogen receptor-positive) types of cancer or fibroid tumors that may develop as a result of alifelong higher mean average level of estrogen. Calcium metabolism is much affected by Vitamin C intake. Patients who suffer from calcium overloadbenefit from supplementing larger daily amounts of Vitamin C because they prevent calcium from calcifyingsoft tissue. Low stomach acid levels are also a common side effect of elevated calcium, for which a higherVitamin C intake is beneficial as well.While the right amount of ascorbic acid increases bioavailability of calcium, very high intake of Vitamin C, if not needed, will eventually put extra demands on calcium stores (bone) and result in calcium deficiency,which can lead to osteopenia, or eventually osteoporosis.
While excessive intake of Vitamin C is reflected in deficient cellular levels of calcium, serum calcium levelsremain unaffected as they are not suitable to measure dietary calcium requirements, so a Vitamin C overdoseis rarely suspect of being the potential cause of numerous calcium deficiency-related side effects such as leg cramps (left-sided only, unless magnesium is also low), light, restless sleep or insomnia, anxieties, increased daytime fatigue, joint pains (more so left-sided), brittle nails with vertical ridges due to low calcium ratios, or increasingly horizontal, groove-like ridges as a result of prolonged, severe deficiency.
It is not uncommon to find copper and zinc levels to be excessively high, making Vitamin C an ideal remedy to lower both, however the large dosages needed can at the same time significantly reduce calcium levels (unless they are high to begin with) to the point of seriously accelerating bone loss. To lessen side effects, one could choose buffered Vitamin C, such as calcium ascorbate or sodium ascorbate (if the kidneys can handle the extra sodium), or simply making sure that adequate calcium is supplemented at the same time.
Some of my patients requiring very large doses of Vitamin C have also taken a small amount of Nickel, which has helped reduce Vitamin C requirements considerably, and with it the detrimental effects of higher dosages of ascorbic acid on the rest of the system (such as possibly lowering calcium too much). While Vitamin C and Vitamin E exhibit synergistic properties in regard to antioxidant activity, unless the one supplemented is truly deficient, increasing its intake also increases the requirements of the other, otherwise a pseudo-deficiency of the other, and a ratio conflict, or balance problem with nickel takes place, which can change vasodilating or vasoconstrictive properties of the coronary arteries. While this poses no problems for the average, healthy individual, it can be detrimental for those suffering from angina-related conditions. (see also Acu-Cell "Nickel & Cobalt" which discusses the relationship of nickel to Vitamin C and Vitamin E).
The above graph illustrates what percentage of the population will enjoy optimal benefits from supplementingextra Vitamin C - not counting dietary sources of Vitamin C. These amounts are based on average, cellularrequirements of Vitamin C, which go beyond the recommended deficiency-preventive RDA/DRI minimum intake.Instead, they take into account the synergistic and antagonistic effect of all other nutrients that interactwith Vitamin C as well, to encompass a much wider scope of disease prevention. However, even optimal requirements tend to fluctuate under specific medical circumstances and may needto be adjusted to meet extra cellular demands (e.g. with injuries, high stress situations, hormonal changes,viral / bacterial infections, or dietary factors such as food binges [chocolate], resulting in copper overload). How much Vitamin C should one supplement?
Vitamin C supplemental requirements not only vary from one person to the next, but they vary for the sameperson over a lifetime. Unfortunately, the optimal dosage of Vitamin C - just like the optimal dosage formany other nutrients - can usually only be established when one has the resources to measure their actualrequirements.The "Bowel Tolerance Challenge" - recommended by some doctors - to determine the optimal intake ofVitamin C by ingesting increasing amounts of ascorbic acid until diarrhea sets in, then reducing Vitamin Cto a tolerated dose, only measures one's tolerance to the type of ascorbate, and the amounts used, but itdoes not reflect optimal Vitamin C intake to achieve optimal benefits.
If uncertain what one's actual requirements are, 500 mg of Vitamin C / day is universally considered to besafe, mostly free of side effects, and covers minimum requirements, even though that amount will not be anoptimal dosage for a large portion of the population.If a daily multi-vitamin/mineral pill is taken, it may be best to just use a basic brand with as many essentialingredients as possible, but not much higher than the RDA / DRI, despite the fact that this may also notprovide optimal amounts of nutrients. The reason is simply that no brand is able to provide all essentialnutrients in their optimal configuration for an individual, so mega dosages not only create the potential forside effects, but also the possibility of creating ratio-induced pseudo-deficiencies of any nutrients left out. Randomly overdosing or megadosing on single nutrients (including Vitamin C) creates a risk of significantlyimbalancing one's system, and it makes little difference whether or not water-soluble vitamins such asVitamin C, or B-Vitamins are used. While excessive intake of fat-soluble vitamins, as well as overdosing onany number of minerals can be toxic, even water-soluble nutrients can cause side effects, or do an amazingamount of damage when regularly overdosed on during their sometimes short journey through the body. Any time a single nutrient is supplemented at excessive amounts, one is really dealing with a much morepowerful drug-like effect. And although this has a greater potential to help a medical situation, it equallyhas the potential of making a particular medical condition worse, or even create new ones if inappropriatelyused. Supplementing above-RDA / DRI amounts of Vitamin C will most certainly have a positive effect onpeople's general health, however the decision to megadose on Vitamin C (> 5,000 mg) - or any othernutrient - should at least be supported with some valid reasons or clinical evidence. In most cases, it isthe synergistic effect of several similar nutritional compounds that yield the best results because of theirmore food-like attributes, and their lesser chance of provoking side effects.
Being educated about nutrition and trying to improve one's health is highly commendable, but at the sametime it also helps to have a medical professional check out what all that supplementation is actually doingto one's system.
Vitamin C supplementation during Pregnancy and Nursing:
If pregnant women take higher amounts of Vitamin C, it is advisable to reduce their Vitamin C intake to between 250 - 500 mg per day shortly (one to two weeks) before delivery, otherwise the baby will become Vitamin C-deficient after birth until the body adapts to being "cut off" from a higher supply of Vitamin C while in the womb. This is not necessary if the baby is breastfed, because it will continue to receive the higher amount of Vitamin C from breast milk. However when the time comes to wean the baby, the same routine needs to be followed, where the mother will have to reduce a higher intake of Vitamin C to that lesser amount to prevent the baby from temporarily becoming Vitamin C-deficient.
Ascorbic Acid, or Vitamin C is an essential nutrient that Humans, as well as Apes and Guinea pigs mustobtain from dietary food sources. Most other animals produce ascorbic acid in the liver from glucose, and inmuch higher amounts than we get from our diets today. Vitamin C is found mostly in fruits and vegetables, where the highest concentrations are in fresh, raw foods,while whole grains, seeds, or beans contain very little Vitamin C, except when they are sprouted, which raisesthe ascorbic acid content. Similarly, animal foods contain almost no Vitamin C, although raw fish providesenough ascorbic acid to prevent Vitamin C deficiency symptoms (listed below). Vitamin C is water-soluble andone of the least stable vitamins. Cooking counters the benefits of Vitamin C by destroying much of it in food,and it is easily oxidized in air and sensitive to light. Being mostly contained in the watery part of fruits andvegetables, Vit C is also easily lost during cooking in water, so the steaming of vegetables minimizes its loss.
Rutin and Hesperidin are the main flavonoids / bioflavonoids - or accessory nutrients - that form anascorbic acid or Vitamin C complex. Both function synergistically with Vitamin C to benefit numerous healthissues which are addressed further below.
Ascorbic acid was isolated from lemons in 1932, following the discovery that its deficiency causes scurvy.[76]It was first written about circa 1500 B.C. and described by Aristotle in 450 B.C. as a syndrome characterizedby lack of energy, tooth decay, gum inflammation, and bleeding problems. A high percentages of sailors withthe British navy and other fleets used to die from scurvy until James Lind discovered that the juice of lemonscould cure and also prevent the disease. The ships then routinely carried limes for the sailors to consumedaily, and thus these sailors became known as "limeys." Only about 10 mg of Vitamin C is necessary toprevent scurvy.
Ascorbic acid is used up more rapidly with alcohol use, smoking, and under stressful conditions. Otherfactors that increase Vitamin C requirements include viral illness and fever, Aspirin and other medications(sulfa antibiotics, cortisone), environmental toxins (DDT), and exposure to heavy metals such as mercury,lead, or cadmium. Vitamin C is involved in the formation and maintenance of collagen, which is the basis ofconnective tissue found in capillary walls, skin, ligaments, cartilage, vertebral discs, joint linings, bones andteeth. Collagen, and thus Vitamin C, is needed for wound healing and to maintain healthy blood vessels. Vitamin C helps the absorption of iron (particularly the vegetable, or non-heme form), so it is helpful foriron-deficiency anemia. Other conditions that benefit from ascorbic acid metabolism include diabetes (forinsulin production), certain cases of male infertility, as well as arteriosclerosis, atherosclerosis, cataracts,glaucoma, and musculoskeletal degeneration (mostly by Vitamin C keeping calcium soluble and preventing itfrom calcifying soft tissue).
Vitamin C helps thyroid hormone production and the metabolism of folic acid, tyrosine, and tryptophan, andit stimulates adrenal function and the release of norepinephrine and epinephrine, which are stress hormones.However, prolonged stress depletes Vitamin C in the adrenals and decreases blood levels. Ascorbic acid isimportant in cellular immune functions, where it is beneficial for bacterial, viral, and fungal diseases.At higher amounts, Vitamin C may decrease the production of histamine, thereby reducing allergy potential.A combination of very high doses of Vitamin C + Vit E + Vit B12 has been found effective in lessening thesymptoms of shingles (herpes zoster), provided they are all taken at the earliest onset of the attack. ¤ Vitamin C Synergists:Nickel, Iron, phosphorus, germanium, selenium,tin, Vitamin A, adrenals, [cobalt, Vitamin B15]. DRI (RDA):0 - 6 months6 - 12 months1 - 3 years4 - 8 years9 - 13 years14 - 18 years
19 - 30 years31 + years
pregnantlactating
smoking Therapeutic Range: 250mg - 50,000mg+ UL: 400mg - 2,000mg
Best time to take Vitamin C: Morning to evening, in divided doses, preferably with the 3 main meals.
"Nickel & Cobalt" provides additional information on Vitamin C and its interactions with Vitamin E, B12, & B15._________________________________________________________________________________
Cellular / Intracellular Attributes and Interactions: Low Levels / Deficiency - Symptoms and/or Risk Factors: Scurvy, slow wound healing, anemia, easy bruising, micro-hemorrhages, nosebleeds, shortness of breath,fatigue, gastrointestinal problems, frequent infections, dermatitis, chronic gingivitis, impaired formation andmaintenance of collagen, impaired multiple hormonal functions, increased risk for various cancers, arthritis,reduced insulin production, some types of male infertility, vascular degeneration, depression, gallstones. High levels / Overdose / Toxicity / Negative Side Effects - Symptoms and/or Risk Factors: Diarrhea, abdominal cramps, high stomach acid, increased urination, insomnia, irritability, PMS, joint pains,calcium deficiency, osteoporosis, headaches, hypoglycemia, weakness, anemia, reduced estrogen, reducedprogesterone, reduced prolactin; may increase infections by causing copper or zinc deficiency._________________________________________________________________________________ Vitamin C Food Sources:Citrus fruit, green peppers, sweet and hot peppers, potatoes, spinach, parsley, cabbage, broccoli, Brusselssprouts, turnip greens, rose hips, black currants and other berries, kiwi, tomatoes, horseradish, watercress. ¤ Males40 mg AI50 mg AI15 mg25 mg45 mg75 mg
90 mg90 mg
120 mg Females40 mg AI50 mg AI15 mg25 mg45 mg65 mg
75 mg75 mg
80 - 85 mg115 - 120 mg
110 mg Vitamin C Antagonists:Manganese, zinc, calcium, Vitamin E,copper, [cobalt, Vitamin B12], estrogen.Optimal Vitamin C intake chart_________________________________________________________________________________ 2014 Dietary Reference Intake (DRI) - Recommended Dietary Allowance / Intake (RDA / RDI) forAdults, Children, Pregnancy & Nursing - Adequate Intake (AI) - Tolerable Upper Intake Level (UL)
est time to take Vitamin C: Morning to evening, in divided doses, preferably with the 3 main meals.
"Nickel & Cobalt" provides additional information on Vitamin C and its interactions with Vitamin E, B12, & B15._________________________________________________________________________________
Cellular / Intracellular Attributes and Interactions: Low Levels / Deficiency - Symptoms and/or Risk Factors: Scurvy, slow wound healing, anemia, easy bruising, micro-hemorrhages, nosebleeds, shortness of breath,fatigue, gastrointestinal problems, frequent infections, dermatitis, chronic gingivitis, impaired formation andmaintenance of collagen, impaired multiple hormonal functions, increased risk for various cancers, arthritis,reduced insulin production, some types of male infertility, vascular degeneration, depression, gallstones. High levels / Overdose / Toxicity / Negative Side Effects - Symptoms and/or Risk Factors: Diarrhea, abdominal cramps, high stomach acid, increased urination, insomnia, irritability, PMS, joint pains,calcium deficiency, osteoporosis, headaches, hypoglycemia, weakness, anemia, reduced estrogen, reducedprogesterone, reduced prolactin; may increase infections by causing copper or zinc deficiency._________________________________________________________________________________ Vitamin C Food Sources:Citrus fruit, green peppers, sweet and hot peppers, potatoes, spinach, parsley, cabbage, broccoli, Brusselssprouts, turnip greens, rose hips, black currants and other berries, kiwi, tomatoes, horseradish, watercress. ¤ Males40 mg AI50 mg AI15 mg25 mg45 mg75 mg
90 mg90 mg
120 mg Females40 mg AI50 mg AI15 mg25 mg45 mg65 mg
75 mg75 mg
80 - 85 mg115 - 120 mg
110 mg Vitamin C Antagonists:Manganese, zinc, calcium, Vitamin E,copper, [cobalt, Vitamin B12], estrogen.Optimal Vitamin C intake chart_________________________________________________________________________________ 2014 Dietary Reference Intake (DRI) - Recommended Dietary Allowance / Intake (RDA / RDI) forAdults, Children, Pregnancy & Nursing - Adequate Intake (AI) - Tolerable Upper Intake Level (UL)
Vitamin C / Ascorbic Acid:by Dr. Ronald Roth_________________________________________________________________________________
General recommendations for nutritional supplementation: To avoid stomach problems and improve tolerance,supplements should be taken earlier, or in the middle of a larger meal. When taken on an empty stomach orafter a meal, there is a greater risk of some tablets causing irritation, or eventually erosion of the esophagealsphincter, resulting in Gastroesophageal Reflux Disease (GERD). It is also advisable not to lie down right aftertaking pills. When taking a large daily amount of a single nutrient, it is better to split it up into smaller dosesto not interfere with the absorption of other nutrients in food, or nutrients supplemented at lower amounts.
