The human body is marvellously equipped to cope although anyone reading this probably has a few body systems that aren't obliging! I know mine doesn't, BUT common sense things such as making sure your body has all the fuel, right ingredients etc to do its best is crucial. A balanced diet incorporating vitamins and minerals in recommended daily intakes is ideal. Some of our foods don't contain all the vits and mins they should, so being aware of what might be missing and what might need a top-up is good. This is not medical advice, just basic nutrition. Check out everything with your team but I am sure they will not have a problem with you taking Vitamin A and D which our bodies tend to be short on in the winter. These along with essential nutrients such as selenium and glutathione are key for fighting infections.
There are a handful of foods that naturally contain glutathione, including asparagus, avocado, cabbage, Brussels sprouts, spinach, broccoli, garlic, chives, tomatoes, cucumber, almonds, and walnuts. Some of those contain selenium also. It is interesting that one of the reasons put forward by scientists to explain why the elderly are more vulnerable to respiratory infections is that Vitamin a, D, and Glutathione are often only present at very low levels. Happy chomping! Stay healthy!