Since time immemorial, people have known that the cold weather brings more frequent colds, and now, (as of 2015) humanity finally knows why.
It's because your nose is cold!
A colder nasal cavity simpy renders you're immune system less effective in the main place viruses lay dormant in the body, the colder temperature means slower chemical reactions. https://news.yale.edu/…/cold-virus-replicates-better-cooler…
So now, along with making sure you're getting plenty of sleep, Vit C and Zinc, you can add the nose warmer to your cold prevention and amelioration regime ;)
(picture from www.nosewarmer.com)
Foods to boost your immune system
Fruit (not citrus), organ meats, starchy vegetables (potatoes with skin left on)
Tomatoes, citrus fruit, red capsicum, broccoli, kiwi fruit
Sunflower seeds and oil, healthy oils, almonds, peanut butter
Whole grains, legumes, nuts, seeds, leafy greens
Oysters, beef, crab, poultry, beans, nuts, pumpkin seeds, wholegrains