I used to think that if a child moves from a typical diet to a "healthier diet" more based on whole foods, that they would get more vitamins and minerals because often a restricted diet (like a gluten free diet, a casein free diet or a vegetarian diet) contains more healthy foods. But there are several factors at work which cause this not to be the case. First, when you remove a food group, like wheat or dairy, you are also removing a source of supplementation, because both wheat flour and milk are fortified with vitamins. Even though cereal is totally junk food, it is fortified and in many cases contains a third of the vitamins you need for the day. So when you remove this mainstream food, you are also removing vitamins from the child's diet.
In addition, although a child may be eating healthy food, you really don't know what they are absorbing. Although it would seem like food sources would be the best way to get these important vitamins and minerals, if children are deficient in one mineral they can have trouble absorbing another. So you might know you are low in iron, eat red meat, but not absorb iron because you are low in copper, which is necessary to absorb the iron.(2) Also, some vitamins (like B6 and B12) which are critical for brain function are synthesized in the gut by beneficial bacteria. We have evolved to create these vitamins ourselves so our brains don't starve when we can't get them from food sources. But, if bad bacteria takes over the gut and there isn't the right balance of bacteria these vitamins cannot be created. In addition, the stress of toxins use up these B vitamins quickly.(3) In this case supplementation is necessary. And finally, food is generally less nutritious than it was years ago.(4)
We were fortunate to have a lot of access to nutritional testing when my son was sick which led us toward supplementation and better health.
I didn't know how important a multivitamin was at the time. But it was obvious to me that my 18 month old son was desperately low on vitamins--his brain and body were starving. He had gone from the 90% of weight at 12 months to the 6% of weight at 17 months and his iron level was below 10 (normal was above 40.) An alternative test showed that he was low on B12 and a doctor friend ordered me to go directly to the pediatrician and get a blood test for B12, homocysteine and methylmalonic acid. His B12 level was 324 (there was no normal range for kids under 5 and normal for adults was above 200) but there was a note on the test that a percentage of people had problems with levels between 200 and 400. And his methylmalonic acid level was elevated indicating a low B12 level despite being in a the so-called "normal" range.
I stumbled upon the Nutristart multivitamin at Whole Foods, which my son took for almost three years. He began to speak after B12 with folic acid from the vitamin shop. And he grew more alert and functioned better when I gave him probiotics. Not everyone has such a response to vitamins, but children whose brains are starving for nutrients can have dramatic responses to supplementation. In other cases, kids systems are such a mess that they are unable to break down vitamins. This was the case with my daughter until we discovered she had a thyroid problem.
Which is why I recommend trying samples of vitamins to see how your child reacts and trying a different product if they have a bad reaction to a particular vitamin. Everyone is different and what works for my children might not work for your children. Food sources are the best place to get vitamins and minerals, but a multivitamin with minerals like Nutristart Multivitamin Powder or Hero Multivitamin with Minerals is insurance that they have the necessary nutrients to absorb nutrition from the food they are eating.
(1)from Vegetarian Diets: Advantages for Children:
"Consuming foods rich in vitamin C, such as orange juice, with iron-rich foods enhances the absorption of iron. Some foods are naturally rich in both iron and vitamin C, such as broccoli, Swiss chard, and other dark green leafy vegetables. Other good iron sources include iron-fortified cereals, enriched bread, pasta, rice, soybeans, chickpeas, and blackstrap molasses. Dairy products are extremely low in iron and may interfere with iron balance, especially in very small children."(2) http://www.whfoods.com/genpage.php?tname=nutrient&dbid=53
(3) The Best Vitamins for Removing Toxins
From Should You Give Your Child a Multivitamin:
"A recent survey found that children between ages two and eighteen receive only about 40% of the daily value for vitamin A, 30% of the daily value for vitamin E, and 60% of the daily value for magnesium. The average American child also consumes insufficient quantities of other essential nutrients including iron, zinc, and vitamin B6. Although these deficiencies are not pronounced, if they are not corrected, over time they can rob a child of reaching his or her full potential as they impair growth, hinder immune defenses, and produce a wide range of shortcomings that are associated with marginal deficiencies. "
(4) "Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999" (J. Am. Coll. Nutr. 23: 669-682,2004) studied 50-year changes in U.S. Dept. of Agriculture food composition data for 13 nutrients in 43 garden crops-vegetables plus strawberries and three melons. Study found apparent declines in median concentrations of six nutrients: protein -6%, calcium -16%, phosphorus-9%, iron-15%, riboflavin-38%, and vitamin C about -20%. nutrient-dense foods.