Boosting Immune System

[stasher]

Does anyone know good ways to boost your immune system? I have 2 children, ages 2 1/2 years and 6 1/2 months old, and they get colds all of the time. My infant has had 4 colds since he was born. We have been vegan for 2 years now and eat pretty well. We take multi-vitamins and get exercise every day. It's getting very frustrating because I thought eating a vegan diet would keep us from getting sick and that's not happening. Also, I thought babies who are breastfed aren't suppose to get sick too often and my baby has been sick 4 times already. Right now they are battling a bad cold - cough, congestion, and running nose. Luckily they've never had a serious infection that needed antibiotics, but they've had there share of bad colds.

My mother-in-law swears by garlic - is there a kid's garlic supplement?
What is the best vegan multi-vitamin for adults and kids?

Should we cut out all wheat products?
We don't eat much sugar, maybe a little bit in maple syrup with pancakes on the weekends and a little sugar in condiments.
Should we completely eliminate sugar?

I was thinking of trying a raw diet, but I'm not sure if I could do it - I think it might be too time-consuming (I'm so busy with the 2 and so tired b/c I'm not getting any sleep) and too much raw veggies may bother my infant (through my milk). Has anyone nursed a baby and been on a raw diet?

I appreciate any suggestions you may have.

Thanks,
Shelly