Do you seem to catch every virus that is going around? I used to and I'd be sick for weeks every time. Recently, I realized that for the past two years, I've only had two colds per year. And this last winter, the two colds I had only lasted three days each. This is a huge change for me and I can only think of two things that I've been doing differently. One is taking an Emergen-C packet every day and the other is making smoothies with whey protein powder.
I had no idea whey protein was an immune booster until I saw it on my canister of protein powder. I looked it up online and, sure enough, it is known to support the immune system. You can read an article that explains the how and why of it HERE.
Making a low-cal fruit smoothie with protein powder is easy. I put one cup of fruit in a blender, add a teaspoon of sweetener (I use fructose but I'm trying to switch to Stevia), 3/4 of a scoop of whey protein, a tablespoon of almonds (for some healthy fat) and about a half cup of water. You can also use milk or soy milk if you like your smoothies creamier. It's a delicious way to boost your immune system and it's good for your muscles too.