How much vitamin C do you need?
The government’s Recommended Daily Allowance (RDA)—90 milligrams (mg) of vitamin C per day for adult men and 75 mg per day for adult women—is enough to prevent scurvy, a potentially fatal disease in which the body literally falls apart due to vitamin C deficiency. (Vitamin C is needed for making collagen, an essential component of the connective tissue that holds the body together.)
But vitamin C does a great many more things in our bodies than help us make collagen. In fact, it probably does more to keep you well and vital than any other molecule you can put into your body.
Vitamin C is essential to:
- repair of injury
- immune function
- our ability to handle stress
- healthy hormone activity
- healthy neurotransmitter function
- energy production
- iron utilization
- nitrous oxide functions (which help with energy and also with healthy blood pressure)
- healthy bone formation, and
- optimal brain function
And to top it all off, vitamin C is the most important water-soluble antioxidant you can ingest and helps to recycle glutathione, the key antioxidant produced by the body. As a potent antioxidant vitamin C has a protective effect on DNA, RNA, and all of our cells, tissues and body functions.
As a result, vitamin C experts have recommended up to 6,000 mg (6 grams) as a MINIMUM daily intake, with MANY TIMES that amount under a variety of conditions including stress, illness, and wound-healing.
You may be surprised to learn that all humans have a genetic defect! Almost all animals—with the exception of guinea pigs, fruit bats and primates, including chimpanzees, monkeys and humans—have enzymes that convert common glucose (blood sugar) into vitamin C. Four enzymes in all are required. We have three of them but not that crucial fourth.
When other animals ingest, say, a cancer-causing toxin (a carcinogen) their bodies immediately synthesize 10, 20, and even 50 times as much vitamin C as normal to meet the increased need. Scientists have observed that humans try to synthesize more vitamin C under these same conditions by activating the three relevant enzymes that we have, but without that fourth enzyme, it’s a no-go.
Our need for vitamin C escalates dramatically whenever we ingest any type of toxin, or when we’re wounded, get an infection, or undergo significant stress, but unlike most animals, we can’t manufacture it.
Nobel-prize winning scientist Linus Pauling based his estimation of our need for vitamin C on animal studies. For example, a goat weighing 110 pounds will normally make over 9,000 mg (9 grams) of C a day. That would translate into about 13 grams a day for a 154-pound human.
We generally recommend at least 3-6 grams daily, but your own body can tell you how much you need. Taking too many causes' gassiness, stomach rumbling and ultimately diarrhea. In other words, the body will eliminate what it doesn’t need.
TAKING VITAMIN C TO BOWEL TOLERANCE
Beyond Health recommends that almost everyone takes vitamin C (powder) for bowel tolerance.
Start out with a small amount and very gradually increase it at your own pace, gradually taking a little more each day.
Vitamin C loses its effectiveness relatively quickly, so take small amounts frequently rather than large amounts less frequently, at roughly equal intervals throughout the day.
Vitamin C can be taken with or without food. Many people find it easiest to take some upon awakening, some with each meal, and some before going to bed at night.
If at any time along the way, you get abdominal discomfort: a rumbling stomach, excessive gas, or diarrhea, go back to the amount you reached before you encountered problems. Use this as your maintenance dose.
Whereas most people tolerate 6-20 grams/day, there have been cases where 50 and even 100 grams have been needed to reach bowel tolerance. The ability to tolerate such large amounts means these large amounts are needed.
Similarly, if you are coming down with any kind of infection, your body requirements for vitamin C go way up. At the first sign of a cold or flu, take ½-1 gram of C every hour or even every half hour, and you can usually nip that virus in the bud.
This may require 20 to 50 grams, or, although rarely, even more.
If you are unable to prevent the cold or flu, continue the same frequent doses of vitamin C, and your recovery will be much, much quicker.
Because your body will eliminate what it doesn’t need, taking large amounts of vitamin C is very safe unless you have a rare condition called hemochromatosis in which iron accumulates abnormally AND as long as you’re taking a very pure vitamin C, free from contaminants. “Food grade” is considered acceptable by some; “USP grade” by others. But we weren’t satisfied until we purified our vitamin C three times past USP grade. You can’t buy a more pure vitamin C than that!
- Maxfield L. Vitamin C Deficiency. National Institutes of Health National Library of Medicine. Last update July 4, 2022.
- Wright JW. The “big picture” of vitamin C: The human genetic defect that makes supplementing with this nutrient vitally important. Nutrition & Healing, January 2012, pp. 4-6.
- Fonorow O. Introduction to Hickey S. and Roberts H. Ridiculous Dietary Allowance: An open challenge to the RDA for vitamin C. Copyright Dr. Steve Hickey, 2004. (Owen Fonorow is the co-founder of the Vitamin C Foundation.)