HOW MUCH VITAMIN C DO YOU NEED?

Report #6787 4/21/96

The latest research shows that Linus Pauling was wrong. A recent report in the Proceedings of the National Academy of Sciences shows that the optimal dose of vitamin C is closer to 200 mg per day, not 4000.

Blood levels of vitamin C were first depleted by placing men on a diet that contained fewer than 5 milligrams of vitamin C pe day. Then the men continued their vitamin C deficient diet and took vitamin pills ranging from 30 to 2500 mg of vitamin C each day. White blood cells were saturated at 100 mg per day and couldn't take in any more vitamin C and blood fluid was saturated at 200 mg per day. Beyond 100 mg per day, the volunteers excreted huge amounts of vitamin C in their urine showing that their bodies couldn't retain that much.

At 1000 mg per day, breakdown products of vitamin C called oxalates and those of nucleic acids called urates, started to accumulate in the urine. Each can cause kidney stones in susceptible people. Large doses of vitamin C can also cause liver and heart damage in people who have an inherited condition that causes them to take in too much iron.

This study shows that you can get all the vitamin C that your can keep by eating each day, any one of 2 oranges, 2 grapefruits, 2 peppers, 2 kiwi fruits, 2 cups of broccoli or brussels sprouts or drinking 2 glasses of cranberry juice. Besides, you will also meet your needs for other vitamins, minerals, fiber and phytochemicals that are found in all fruits, vegetables, whole grains and beans.

By Gabe Mirkin, M.D., for CBS Radio News