Vitamin C is probably the best known of all the vitamins, not only for what it does to promote health but also for its availability in foods. Most animals can manufacture their own vitamin C, but humans can't. That's why it's important that we eat a variety of C-containing foods to keep our stores optimum.

Vitamin C is important for many reasons. Its antioxidant properties protect cells from damage. It's vital for synthesizing collagen, the protein that helps reinforce connective tissue, which holds everything in place in our bodies. It boosts the immune system and helps your body make certain hormones.

The ability of Vitamin C to increase iron absorption has been recognized for years, which is one of the reasons we recommend drinking juice with your breakfast cereal. Vitamin C's involvement in protection against colds is still being studied. Certainly, though, drinking juice during illness is not going to hurt, especially if it also contains the B vitamins.

The best food sources of vitamin C are citrus, strawberries and kiwi. Most, but not all, fruits and vegetables contain some amount of this amazing vitamin. Unfortunately, the ascorbic acid found in foods high in vitamin C can sometimes cause sensitivity in young children, usually in the form of a rash. This doesn't mean that your toddler will always have a problem with these foods, but he may need to temporarily avoid them. Usually, the offending foods are citrus juices and strawberries, while many of the other fruits and vegetables are easily tolerated.

While vitamin C is readily available, deficiencies sometimes occur. The first signs of a deficiency are usually bleeding gums and frequent bruising. Healing in general is also slower. Serious deficiency is called scurvy, which affects the bones and teeth and causes a severe lack of energy and, possibly, depression.

Vitamin C toxicity is actually more of a concern than deficiency. When it was announced that vitamin C might be a cure for the common cold, people started taking megadoses. However, excessive ascorbic acid can cause the formation of kidney stones and may also alter their antioxidant properties, making them harmful.

Pregnant women should not take large amounts of supplemental vitamin C. Between daily prenatal vitamins and a healthy variety of fresh fruits and vegetables, there is no reason why any pregnant woman should need to take additional vitamin C at all.

The problem with taking large supplements of C during pregnancy is that babies can develop scurvy-like symptoms after delivery, when this supply is no longer available. We call it pseudo-deficiency: it's not an actual deficiency, but it mimics one as the baby's body continues to look for those high doses. Pseudo-deficiencies do not cause the alarm that an actual case of scurvy would, but they are still a concern.

There are many products on the market that claim exceptional levels of vitamin C, and most of these are safe in moderation. As with any supplement or herb, caution should be used when taking them. Remember, they're still considered chemical substances in your body and can offset the delicate balance of your body chemistry.