Dairy products can thicken phlegm and worsen cold, although it may not have this affect on some. Try and see how it works. Foods that contain processed sugars, alcohol and refined carbs can increase blood sugar levels and inflammation, which in turn reduces white blood cell count, making it difficult for your body to fight the infection.
These foods can worsen your cold or flu within an hour. Here is how what you need to stay away from.
Processed Sugars: Anything loaded with sugars like soda, juices and artificially flavored drinks can cause inflammation and weaken the body’s white blood cell count, which reduces resistance towards foreign organisms.
Dairy: If you have a cold then dairy products can thicken existing phlegm so try and avoid it as much as possible. It may not have this effect on some, so try a bit and see how things work.
Alcohol: Like sugar, alcohol causes inflammation and reduce WBC efficiency. Avoid drinking and stick to broths and fresh juices.
Refined Carbs: They breakdown into sugar and increase blood sugar. This again makes it difficult for your body to fight off and infection.
Read more here – 4 Foods That Will Make Your Cold Or Flu Worse In An Hour