Many of the health institution in the world, including The Committee on Diet, Nutrition, and Cancer, took a stand against use of vitamin C supplements to meet it’s recommendations.

I think that scientists who take this position have one of two reasons. One is a very good one. But the other, in my opinion, is not so good.

The studies that tie vitamin C to cancer prevention usually link foods containing vitamin C rather than the vitamin itself to reduce risk of cancer. There is always the possibility that it is something else in these foods, rather than the vitamin C, that is protecting our health. If this is the case, people who take a vitamin C pill rather than eat vitamin C-containing foods will miss the unknown protective substance. Personally, I think that it is probably the vitamin C itself that is protective, though I also believe that other substance in these same foods may have anti-cancer ability.

Of  course, ideally we should get our vitamin C from foods. But some people just don’t care for vegetables, which supply almost 40 percent of the vitamin C in the industrial countries diet. And some parents have tried, but failed, to to convince their children to eat more fresh fruits and vegetables.

I simply cannot see withholding a moderate vitamin C supplement when this is the case. I think it is unscientific to advocate a diet that contains 200 mg of  vitamin C a day, yet oppose a supplement of this amount for those people who do not eat eat foods rich in vitamin C.

I know that there is a long history of opposition to vitamin supplements. Unfortunately, it has become an automatic response among some nutritionists. I cannot go along with it though, because sometimes it doesn’t make sense.

Can Vitamin C Hurt?

For all the noise that has been made about vitamin C supplements, you would think there were dead bodies lined up next to bottles of vitamin C.

I learned from many research  that in high doses some nutrients can cause more side effects than some drugs. At high doses, a vitamin such as nicotinic acid (a version of the vitamin known as niacin) really is a drug. But when it came to vitamin C, the research led me in a different direction. Try as I might, I could only conclude  that vitamin C was one of the least toxic substances in the pharmacy.

First, I would like to tell you that, in general, the amount of vitamin C that has been reported to cause problems in some people is far beyond the level you would get by eating a diet  rich in fruits and vegetables. But even at high doses, toxic effects appear to be the exception rather than the rule.

But I would like to mention four problems that have been linked to very high doses of vitamin C:

1. Kidney stones and aggravation of gout,

2. Destruction of vitamin B-12,

3. Complications from lack of the enzyme G6PD,

The Kidney Connection

It is true that high doses of vitamin C may speed formation of kidney stones. I have my own experience in this case, when I got the first kidney stones disorder in 1994. This side effect may occur mostly among people who are especially prone to kidney stones. Remember, though, that not everyone who teds to develop kidney stones knows it.

How much vitamin C did it take to bring on kidney stones or the early signs of stones? According to some researches  I learned, this problem has been seen in people taking 4 or more grams of vitamin C every day.

The same process that make kidney stones more likely to form may also worsen gout. People who are susceptible to gout should also take note of these findings.

About Destruction of Vitamin B-12

It is also possible, but probably not likely, that vitamin C may destroy some of the vitamin B-12 in food.

Two decades ago, two scientists put together some laboratory equipment to mimic digestion. They reported that under these “test-tube” conditions, a 500 mg supplement of vitamin C destroyed a high percentage of the vitamin B-12 in food.

When another scientist directly studied this issue in human subjects, the results were different. This researcher examined vitamin B-12 levels in the blood of people who had been taking at least 500 mg of vitamin C daily. He found that only three of the ninety people tested had low levels of vitamin B-12. These three, all fifty to sixty years of age, had been taking a minimum of 1000 mg of vitamin C with each meal for more than three years.

There is one more fact to note:  scientists believe that less vitamin B-12 will be destroyed if the vitamin C is taken two or more hours after eating.

If You Have G6PD Deficiency

High doses of vitamin C can be fatal for you. I found a case that a man who had been given 80 grams of vitamin C for two days as a treatment burns. He died a few weeks later.

It turned out that this patient had a deficiency of the enzyme G6PD. It stand for glucose-6-phosphate dehydrogenase. As its name implies, this enzyme is used in metabolism of glucose, a type of sugar.

Although this man had been given enormous amount of vitamin C, scientists are concerned that others with G6PD deficiency may be sensitive to smaller amounts. If you have this condition, you should be aware of this concern.

About 10 percent of  Afro-American males have mild G6PD deficiency. A smaller percentage of black females are affected, as are a few Caucasians. Screening tests for this condition are readily available.

Regarding the story of vitamin C and cancer, please click here.