In my view the information in the link is, at best, very simplistic.

Its presenter trained as a chiropractor but he seems to know very little about cell biology. All of the usual convenient villains are there, the evils of Big Pharma, vaccines are bad and so on

I wonder if he has been told about Brca-1 and Brca-2. These are two proteins which, when present in mutant form, increase the chances of a woman getting breast cancer and ovarian cancer. Some women, when learning that they have inherited one of these protein, choose to have their ovaries removed and a double radical mastectomy.

The Rb gene product is another example. When present in mutant form this often leads to an eye cancer (retinoblastoma) which has a very good prognosis.

This is personal for me. A dear friend of mine died from colon cancer secondary to Crohn's Disease. I doubt if she would have been impressed if a well-meaning amateur had told her that all she had to do was make her immune system strong (whatever that means) by taking supplements.