When on chemo they have pretty strict guidelines about what vitamins you can take. Some interfere with the chemo drugs. You'll need talk to the oncologist or pharmacy first.
Before starting chemo, my PCP ran a nutrition panel to see if there were any nutritional deficiencies. She wanted to add a supplement, we ran it past the oncologist and the oncology pharmacist to make sure it would be compatible with the chemo protocols. Adding in things, without knowing it they are needed, can cause other issues, as it can throw other things out of balance. Just help her to keep making the best healthy choices regarding diet, hydration, and getting in physical activity.
I found the chart in the book by Dr. Kristi Funk very helpful (Breasts: The Owner's Manual). It details various foods, why we should be adding them to our diet, and how much we need to get the benefits. The book was in our local library, but I enjoyed it, and ended up buying a used copy on Ebay. Hugs!
Please check with her doctor. A pharmacist checks her home med list for interactions. You don’t want to undermine the effectiveness of chemo.
Run that by the Oncologist’s nurse as she may also be able to recommend other vitamins to take also or say which ones not to use.