Vitamin C was the first vitamin identified as a critical nutrient for human life; in the middle of the eighteenth century, James Lind discovered that citrus was critical to prevent and treat scurvy in the British fleet. From this humble beginning, vitamin C has gone from critical nutrient to alleged cure-all, good for everything from colds to cancer.
How true all these claims are is debatable.
Effects of Vitamin C
Proven effects of vitamin C include antioxidant properties; helping form collagen’s connective tissues; helping produce hormones that regulate your metabolism; acting in many different cellular reactions; and in some mysterious way, combating the effects of physical stress.
The adrenal glands store up vitamin C — the only part of the body that does. When the body is under physical stress, vitamin C is released along with adrenalin. Among the stressors that cause this reaction: burns, extreme temperatures, toxic heavy metals, chronic use of certain medications (like aspirin, barbiturates, and oral contraceptives), and smoking. this may be due to the release of immune system cells at these times. Immune system cells create free radicals while they fight off infection, which act on the invaders with an oxidative burst; vitamin C may help neutralize free radicals after the burst, a sort of biological cleanup crew.
Vitamin C is also known to help your body absorb and make use of other vitamins.
Unproven effects ascribed to vitamin C include curing the common cold and preventing cancer and other diseases that may be caused by free radicals. Studies on whether vitamin C cures colds have come back with inconclusive results. We do know that vitamin C acts as an antihistamine, easing cold symptoms like stuffy nose, and that it can work to clean up free radicals left over that might otherwise prolong your illness.
It is possible that diseases caused by free radicals can be prevented by taking vitamin C. However, these claims are still being tested, and it may take some time for real results to come back.
Linus Pauling’s Vitamin C Experiments
Linus Pauling, the famous Nobel Prize for Physics winner, was a true believer in vitamin C. He conducted a number of experiments and decided that the true test for proper vitamin C dosage was to overload the body until toxic effects — diarrhea, for instance — became evident. The highest dose up to that point, he believed, was the proper dose for that person.
In most people, the toxicity level turned out to be 2000-3000 milligrams, or two to three grams, daily. Pauling tested higher doses on sick people. His finds were startling: very sick people, especially end-stage cancer sufferers, could take up to a KILOGRAM of vitamin C before showing toxic effects. He didn’t do further studies on whether the doses were helpful, probably
becuse he wasn’t prepared or able to do a rigorous study.
Effects of Too Much Vitamin C
Vitamin C overdosing is safer on your body than water overdosing; even with its negative effects, you are unlikely to kill yourself with vitamin C. Too much vitamin C can give you diarrhea, abdominal cramps, and nausea, but not death.
There are, however, other negative effects if you take too much vitamin C. If yu’re being tested for diabetes, too much vitamin C can give you false positive or false negative results. Anticlotting medication can be neutralized by large doses of vitamin C.
Large doses of vitamin C can also cause kidney stones in those who have kidney disease, gout (or even tendencies toward it), or genetic abnormalities that make it difficult to break down vitamin C. Because vitamin C enhances iron absorption, it can prove extremely harmful to anyone who has an iron overload.
Some other effects with vitamin C toxicity include headache, fatigue, insomnia, hot flashes, rashes, and urinary tract problems.
Anyone taking high doses of vitamin C who then discontinues or reduces his intake should do so gradually. Overloading vitamin C can cause your body to adapt by accelerating metabolism and elimination of the vitamin, so if you abruptly stop taking it you could inadvertently cause a temporary vitamin C deficiency.
Safe Effective Doses
The FDA has set up certain levels as safe effective dosage for vitamin C. A meager 10 milligrams per day prevents scurvy. Thirty milligrams is enough to support metabolism.
For men, the FDA recommendation is 90 mg/day; for women, 75 mg/day.
This recommendation changes depending on other circumstances. For instance, if you smoke, men should take 125 mg/day, and women should take 110 mg/day. Because this is the free-radical clearing dose, it’s also a good target for when you’re sick. Still, this is only about 160% of the standard RDA. It isn’t unusual for supplements to include doses as high as 1000 mg — about ten times the RDA.
The FDA believes that in normal circumstances, your body can’t absorb more than 200 mg/day effectively, and 2000 mg/day is as much as any adult should consume daily in the normal course of things. At 3000 mg/day, adverse effects will probably appear.
The Least You Should Know
Water-soluble, so take with a full glass of water.
Adult RDA: 75-90 mg daily for most people
Max recommended: 2000 mg/day (disputed by some)
Must be taken daily for good health; the body does not carry large reserves.