7 Things You Don't Know About Colds

You've been told that drinking milk doesn't cause a sick person to make more mucous and that the phlegmy feeling you may notice is the liquid temporarily coating your irritated throat. Still, you figure there's no harm in easing up on the dairy until your nose has stopped running—or until cold season is over. This strategy really won't help, says Collins, and it could backfire. She explains that the vitamin D in milk can also boost your energy while your body is fighting off pathogens, and the liquid will keep your tissues hydrated. What's more, vitamin D spurs cell growth and helps keep your immune system working optimally—potentially preventing you from getting sick in the first place. Those who are still firmly anti-milk (for whatever reason) can get their vitamin D from fish like swordfish, salmon and tuna, or from fortified orange juice or cereal.