I have started taking Vitamin D in the hope it would boost my immunity against catching colds.
I do take issue with the posters who say Cod Liver Oil is bad. My husband has Ankoloysing Spondolitis (sorry not sure of spelling) arthritis of the spine. This first came on when I first knew him age 29. Sometimes he could hardly walk for the pain. He read about cod liver oil and started to take it off of the spoon. Within 3 months the pain had gone and he has taken it every day since and he is now 70 years old.