Redundant Supplementation
While vitamins are important for proper operation of the human body, a well-balanced diet rich in vegetables and fruits provides more than enough of the daily requirement of vitamins. Taking additional vitamins is mostly a superfluous endeavor that wastes time and money. In certain circumstances, taking excessive amount of vitamins may even be harmful to your child's health.
Who Needs Vitamin Supplements?
Only a select group of people need to take vitamin supplements. This small population includes pregnant women, breastfeeding mothers, premature infants, older individuals, and children with specific medical conditions, such as cystic fibrosis and other rare digestive disorders. Some people need special vitamin supplementation while they're taking certain types of medications, such as isoniazid (a medication used to treat tuberculosis). Your physician will recommend and prescribe such vitamins when the situation warrants it.
The official statement from the American Dietetic Association should send a clear message to all parents: “The best nutritional strategy for promoting optimal health and reducing the risk of chronic disease is to wisely choose a wide variety of foods.” Dieticians do not recommend supplemental vitamins, and neither do doctors.
While medical professionals do not recommend that children follow a strict vegetarian diet, some cultural and religious practices make this type of diet necessary. It is possible to maintain a balanced intake of nutrients while following these restrictive diets, but it takes a wealth of nutritional knowledge and advanced menu planning to achieve it. If your child is a strict vegetarian, consult your doctor or a dietician before starting vitamin supplementation.
Too Much of a Good Thing
Just because vitamins are essential for the body doesn't mean your child should take a lot of them. Too much of a good thing can be a bad thing. Most pediatricians do not recommend that healthy growing children take a daily dose of vitamins. Just as excessive water can damage your brain, excessive amounts of vitamins can cause serious toxicity.
Fact
Scientist Linus Pauling promoted the belief that 75 percent of all cancers could be cured or prevented by high doses of vitamin C. No scientific studies have ever confirmed this hypothesis. He also claimed that by taking large quantities of vitamin C, people could cut their chance of catching a common cold in half. This belief has never been endorsed by any reputable scientific or medical organization.
For instance, taking too high a dose of vitamin A can cause swelling of the brain and death. Excessive amounts of vitamin C can trigger the formation of kidney stones. You should never indiscriminately supplement your child's diet with vitamins, especially when you are using more than one vitamin source.
Lack of Regulation
You might expect the government to have a tight control over vitamins and other supplementations sold in health-food stores, but this is not the case. Vitamins are technically not medications, so the FDA does not have jurisdiction over their safety and distribution. What makes the matter even worse is that these supplements can be obtained without a prescription, so misuse (either unintentional or purposeful) can run rampant.
Most of these supplements do not undergo the vigorous clinical testing that all prescription medications are required to go through before they receive government approval. Furthermore, their purity and efficacy are not regulated at all. Some may be overly potent, while others can lack any active ingredient.
Alert!
Just because these supplements are not medications does not mean they are harmless. Many supplements are proven to be able to alter chemicals in the brain and elevate blood pressure. Some herbal supplements can be just as potent as prescription medications, and their effects may be harmful for some children.
Due to this lack of oversight, most pediatricians do not recommend that children take over-the-counter vitamins. If your child has a medical condition that requires him to take additional vitamins, the physician will actively prescribe them to you. It's not worth the risk to take chances with these unregulated chemicals.

