The infant/child with SPD should never be Iron, Vitamin B, or Magnesium deficient.
Having said all this, you would typically need to have a blood test done to determine Iron, Vitamin B or Magnesium levels in the body. I was unfortunate in that I could never expose Hein-Chris to the trauma of drawing blood. He simply did not (and still does not) have the emotional and physical resources to cope with the pain and fear. It would only reinforce his belief that everything on earth is dangerous.
I had to guess he might be suffering Iron, Vitamin B and Magnesium deficiencies based on what I saw him eat. The infant/child with SPD will often not tolerate a balanced diet. While you might be able to convince/bribe/force/coax an infant/child without SPD to eat a variety of foods (healthy foods children typically don’t like), the infant/child with SPD will not be swayed. In most cases they simply cannot tolerate the smell, taste and texture of the food, making it physically impossible to consume. It is not an act, and parents with infants/children without SPD will not get it. I don’t blame them. I can hardly understand it myself, but it is a stark reality in the life of an infant/child with SPD. Make peace with it.
My strategy was to:
I never discussed this strategy with Hein-Chris’ paediatrician. My decision to use supplements was based on my own research and instinct - and the dosages were such that there was no risk to Hein-Chris. However, talk to your paediatrician about these supplements before administering them - especially if your infant/child is taking medication of any kind.