My immune system hasn't really changed as far as catching colds - I still catch them the same as before.
One thing that has changed is in recent bloodwork it was found that I am vitamin D deficient. So weird because I drink a minimum of 2 glasses of NF milk a day, sometimes more. Either in a latte in the morning or I make my oatmeal with milk and have more milk later. I also take a multi vitamin and sporadic calcium. My surgeon advised me to take 50,000 units of vit D a week for two months to catch up. I'll be honest, I haven't been becaue taking that much even spread out during the week really upsets my stomach. So, now that the sun is out, I've been spending more time outside trying to get it that way. And now that I know I'm deficient, I have had symptoms of the deficiency. I just didn't realize what was causing it.