Walter is a 5-year-old boy who lives in the united states. based on the research, if he has a nutritional problem it is most likely to be calcium deficiency.
The most common nutrient deficiencies among young children in the U.S. are calcium, iron, magnesium, potassium and vitamin E. It has been documented that the two most standard nutritional deficiencies seen in normally healthy children in the United States are iron and vitamin D deficiencies.
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