Vitamin C: How Much Is Enough?

How much Vitamin C do we really need?

The RDA for vitamin C is set at 90 mg a day for men and 75 mg daily for women. Besides supporting immune function, this vitamin improves heart health, is a building block for collagen needed for skin, gastrointestinal and joint health, and has been shown to kill certain cancer cells among other functions.

Additionally, besides getting vitamin C from food sources, you can either take it orally in supplement form or have it administered intravenously. How you get it determines how much you need. When taken orally, which is typically the way most of us get it, intestinal absorption among other factors determines how much is actually concentrated in your blood. It’s also important to note that stress depletes vitamin C and who isn’t under stress these days? Taken intravenously bypasses digestion and absorption is more effective.

According to cardiovascular research scientist and doctor of pharmacy, James DiNicolantounio, optimal doses can be as high as 1,250 mg twice daily and while even 2.5 grams daily doesn’t necessarily produce full saturation, it still may have benefits.

Keep in mind that vitamin C is a water soluble vitamin so it is not stored in your fat cells. This is why it must be taken on a daily basis. Also some of what you take is excreted. Research has shown that bioavailability was effective and complete for a single 200 mg. dose. In those tested no vitamin C was excreted below a 100 mg. dose. So the conclusion was reached that the minimum effective dose should be 200 mg daily. The optimal dose will likely be much higher.

For example: you would need to take 1,250 mg. of vitamin C twice a day to achieve 80 μm (μm represents concentration in the blood); and 5 grams (5,000 mg) a day to achieve 250 μm. So even taking 2.5 grams daily doesn’t necessarily result in fully saturated vitamin C blood levels. Also it is important to note that it is more effective to take it in divided doses throughout the day rather than one large dose to get the best results.

Years ago I had bio-impedance testing done that revealed my body required much more vitamin C than I was currently taking. And I thought I was taking a lot! Increasing my intake in divided doses to 4,000 mg. daily has helped me get some serious gum issues under control. When I am fighting off a cold or exposed to someone who is, I typically increase that to 1,000 mg. per hour throughout the day for a day or two.

Many naturopathic doctors recommend taking vitamin C throughout the day until you reach bowel tolerance, that is until you begin to experience diarrhea, and then back off a bit to the effective amount for you.

My suggestion is to pay attention to your body and use vitamin C daily. It isn’t stored so you won’t overdose on it as you can with fat soluble vitamins. Particularly during cold and flu season, it’s important to get enough daily.