Vitamin C Supplements: Who Needs Them and How Much Is Too Much

The NIH Office of Dietary Supplements says most people here get enough vitamin C from food and drinks. It also says a real shortage is rare in the United States and Canada.

That is the line the shelf never prints. A whole aisle is built on a gap that most shoppers do not have.

Fruit and vegetables are the best sources. Citrus fruit and its juice, red and green pepper and kiwifruit carry a lot. Broccoli, strawberries, melon, baked potato and tomato carry some.

There is a real list and it is short. People who smoke, or who live with smoke, because smoke raises how much the body needs. People who eat a very small range of food. And people with some health conditions, such as poor gut absorption, some cancers, and kidney disease that needs dialysis.

MedlinePlus adds that people who are pregnant or nursing need more. It says to ask your provider what amount is right for you. It also notes that the body cannot make vitamin C and does not store it. That is why it has to arrive most days.

If none of those fit you, the honest answer is that your plate is already doing the work.

Too much brings loose stools, nausea and stomach cramps. Very high intakes can rarely lead to kidney stones. And in hemochromatosis, which makes the body store too much iron, high doses can make that worse.

The upper limit is the part people miss. It counts every source, food and drinks as well as pills. So a fortified drink and a multivitamin are already on your tally before you open a new bottle.

The National Institute on Aging puts the rest of it plainly. Do not assume more is better. Too many pills, or one nutrient at a very high strength, can do harm. Research so far suggests large doses of antioxidant pills will not prevent chronic disease. And the FDA does not approve supplements for safety or benefit before they are sold.