Taking dietary supplements full of antioxidants could help cancerous tumors grow

Recommended reading on this includes "Do You Believe in Magic" by Dr. Paul Offit, the Director of the Vaccine Education Center and professor of pediatrics at Children's Hospital of Philadelphia (certainly one of the best children's hospitals in the world).

Here is the actual paper: https://www.jci.org/articles/view/169671

As usual, the title is not accurate, as there is no "fuel".

What happens is that the antioxidants, including vitamin C, stimulate the tumors to grow blood vessels.

The tumors with better blood vessels grow faster.

So the antioxidants that are good for you are also good for tumors. Therefore they must be avoided whenever cancer is identified and you have to take medication that is bad for you, but hopefully even worse for tumors.

Some anti-tumor medication has precisely the purpose to prevent the growth of blood vessels. This may stop the growth of the tumor, but it is also obviously bad for your other blood vessels, so it can be used only to gain time until some other form of treatment becomes feasible.

When my mother in law (RIP) was going through treatment for lymphoma, the doctors did in fact advise against taking supplements. Because -- either doing nothing (waste of $$), doing "something" that could likely discourage cell death and therefore maybe cancer, or doing... who knows what? because under-regulated and studied.

Chemo is rough, for sure.

I was advised not to take supplements or antioxidants during chemo.

"The healthier you are, then so too is your cancer." was something that threw me off a bit.

Edit: just to be clear, at the point in which you already have cancer, the most important treatment is the science of chemotherapy. Antioxidants can in turn “strengthen” tumor cells (just as they do regular cells) and cause chemo resistance/refractory.