I would start with a good multi designed for kids with ASD like Klaire Labs Vitaspectrum, Kirkman Super Nu Thera, or Brainchild Nutritionals Spectrum Support. With the omega 3's look for a 2:1 EPA:DHA ratio and some practitioners recommend a 5:1 or even 7:1 ratio. My DD takes 2 of the Coromega packets daily per our biomed dr. That is slightly less than 2:1 but it's close. We have also seen good responses to Behavior Balance DMG, Coenzyme Q10, and acetyl-l-carnitine. She has had mild improvement on the methyl B12 injections but we haven't yet decided whether to continue those past the end of the research study she's currently doing on the shots.

Try www.houston-enzymes.com. Really good info on enzymes and autism.

A good enzyme, probiotic, omega 3, and cod liver oil regimen has been very beneficial to my grandsons health and attentiveness.

I have a 4.5 years old son.These usplement helped us he is more like a regular kid,less tantrum..I give multi vitamin like a candy.,Eye quazen q fish oil,behaveral balance vermont liquid( this is b vitamin complex),grape seed extract liquid 3 drop every day,and colostrum (from kirklandlab,this 3 times better and safe from flue shot)..When he take a shower I put himalayan salt in the bath tube for detox,and I also put lavender oil a few drops as a natural calmer...