Can children vitamins cause hyperactivity in them
No. A 3 yo kid is just normally full of energy.
You need to study some books about nutrition so you know a few things. It is quite rare for children to need vitamin supplements, but by the time they are teenagers (in USA) calcium and magnesium deficiencies are common. You have to learn the business yourself because nutrition is a young science, not well studied yet, and there is a flood of folk remedies that are just dumb. Your only defense is to learn the subject yourself. These books are old but still the most popular introduction:
The average parent quite likely believes that “vitamins are a safe and easy way to give children ‘nutritional insurance.’” However, a study published in the Canadian Medical Association Journal shows that “overdoses of multiple vitamins can pose more of a risk to young children than the nutritional problems they’re supposed to prevent,” says the news service Canadian Press. The study indicated that parental misconceptions as to the value of vitamins was a leading cause of overdose. It is a common mistake to think that if something does you some good, a lot of it will make you a lot better. Talk to your doctor./
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