So much of development is tied to proper nutrition.
Our son has food allergies and oral-motor difficulties with solid foods, which makes it difficult to ensure that he's getting all the nutrition he needs. So, we've consulted with a chiropractor nutritionist who suggested a nutrition test called a Pediatric ION (Individual Optimal Nutrition) profile. The test measures essential minerals, vitamins, fatty acids, and amino acids, among other things and recommends supplements based on these test results.
We recently received the test results and will be adjusting his supplements based on his individual needs. I like this because it tells us exactly what his body needs, so we're not supplementing unnecessary items.